Processes and systems for carbon-negative and water-positive hydrogen production

Abstract

The disclosed technology provides a process for producing hydrogen that is renewable, has negative carbon intensity, and is associated with net water production. The hydrogen is economically, environmentally, and socially superior to traditional hydrogen produced via steam reforming of natural gas or electrolysis of water. Some variations provide a process for producing carbon-negative hydrogen and optionally activated carbon, including feeding biomass to a first heating vessel or heating zone to produce dried biomass and a first recovered water stream; feeding the dried biomass to a second heating vessel or heating zone to pyrolyze the dried biomass and produce a biocatalyst and biogas; feeding the biocatalyst, the first recovered water stream, and the biogas to a third heating vessel or heating zone for biocatalytic conversion, thereby producing H, CO, and optionally activated carbon; and recovering the hydrogen.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 477,764, filed December 29, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to processes, systems and apparatus for converting biomass to hydrogen or activated carbon with low carbon intensity. [Background technology]

[0003] Both carbon and hydrogen have traditionally been produced from fossil feedstocks. Fossil feedstocks include natural gas, oil, coal, and lignite. Historically, carbon in the form of charcoal has been produced by the slow pyrolysis of large amounts of wood in a simple batch process with no emissions controls. Traditional charcoal production technologies are energy inefficient and highly polluting. Historically, hydrogen has been produced by steam reforming of natural gas. Due to the increasing economic, environmental, and social costs associated with fossil feedstocks, renewable resources have become attractive alternatives to fossil sources for the production of both carbon and hydrogen. Summary of the Invention [Means for solving the problem]

[0004] Some variations provide a process for producing carbon negative hydrogen, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating under effective biocatalytic conversion conditions and water-gas shift conditions, thereby producing H and CO; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; (f) recovering the H2 from a third heated vessel or heated zone, wherein the H2 is carbon-negative hydrogen characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0005] As used herein, "biocatalyst" is defined as a carbonaceous material that catalyzes the biocatalytic conversion of biogas into reduced gases. Biocatalyst does not refer to enzymes, yeast, or bacteria for fermentation or enzymatic reactions.

[0006] In some embodiments, a first portion of the biogas is fed to a third heating vessel or heating zone. In other embodiments, no biogas is fed to the third heating vessel or heating zone. When some biogas is fed to the third heating vessel or heating zone, effective biocatalytic conversion conditions in step (c) can result in biocatalytic conversion of the biogas, where the biocatalytic conversion of the biogas is catalyzed by a biocatalyst. There can also be non-catalytic / homogeneous biocatalytic conversion of the biogas, or biocatalytic conversion catalyzed by ash or metals present in the reactor walls or stream.

[0007] In some embodiments, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of the biocatalyst itself. In certain embodiments in which a portion of the biogas is fed to a third heating vessel or heating zone, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of the biogas as well as biocatalytic conversion of the biocatalyst. The biocatalytic conversion of the biogas can be catalyzed by the biocatalyst prior to conversion to a reducing gas.

[0008] In some embodiments, the process further comprises recovering a portion of the biocatalyst from step (b) as a biogenic carbon by-product.

[0009] In some embodiments, the process further includes separating a second recovered water stream from the biogas (e.g., using a condenser). The second recovered water stream can be supplied to a third heating vessel or heating zone to perform biocatalytic conversion of the biocatalyst. The second recovered water stream can be supplied to a third heating vessel or heating zone to perform water-gas shift of CO to produce additional H. In certain embodiments in which a first portion of the biogas is supplied to a third heating vessel or heating zone, the second recovered water stream can be supplied to a third heating vessel or heating zone to perform biocatalytic conversion of the biogas.

[0010] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are one common physical unit that is reused in steps (a), (b), and (c).

[0011] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are arranged sequentially in a continuous process.

[0012] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone operate countercurrently to the solid and gas phases, respectively.

[0013] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each vertical, solids, downflow vessels.

[0014] In some embodiments, the first heating vessel or heating zone contains a substantially inert gas. Additionally or alternatively, the second heating vessel or heating zone can contain a substantially inert gas. In certain embodiments, the second heating vessel or heating zone contains less than 0.1 vol% oxygen.

[0015] The first heating vessel or heating zone operates at a drying temperature, for example, from about 100°C to about 400°C. The second heating vessel or heating zone operates at a pyrolysis temperature, for example, from about 300°C to about 900°C. The third heating vessel or heating zone operates at a biocatalytic conversion temperature, for example, from about 600°C to about 1200°C.

[0016] In some embodiments, the first portion of the biogas is fed to a third heating vessel or heating zone, and step (c) achieves a conversion of the biogas to reducing gas of at least 50% or at least 90%, where the conversion is calculated based on the biogas entering the third heating vessel or heating zone.

[0017] In some embodiments, step (c) achieves at least 25% or at least 50% conversion of biocatalyst to reducing gas, where this conversion is calculated based on the biocatalyst entering the third heated vessel or heated zone.

[0018] In some embodiments, at least a portion of the CO is recycled within the process. CO recycling can enhance the extent of the water-gas shift reaction, thereby making it available, for example, to produce additional H from CO and HO.

[0019] In some embodiments, CO2 is produced in step (c), and at least a portion of the CO2 is recycled within the process. CO2 recycling can be performed to reduce the reactivity of the environment in the previous step, such as in a first heating vessel or heating zone. CO2 recycling can be performed to increase the steam velocity in the previous step. CO2 recycling can be used to improve the extent of the dry reforming reaction, thereby producing additional H2 from CO2 and hydrocarbons (e.g., pyrolysis oil). In certain embodiments, CO2 drives the dry reforming of biogas or biocatalysts to produce additional reducing gas.

[0020] In some embodiments, the carbon intensity of carbon-negative hydrogen is less than -3,000 kg COe per metric ton of H. In particular embodiments, the carbon intensity of carbon-negative hydrogen is less than -10,000 kg COe per metric ton of H.

[0021] In some embodiments, the process is a water-positive process characterized by a net water production of greater than 0 kg HO per kg H. The net water production can be, for example, at least 3 kg HO per kg H, or at least 6 kg HO per kg H. In preferred embodiments of a water-positive process, no water is added to the process. Rather, the process utilizes water that enters with the biomass and water produced in chemical reactions during pyrolysis of the biomass.

[0022] In some embodiments, the process further includes supplying the metal oxide and H or CO to a fourth heating vessel or heating zone operating under effective metal oxide reducing conditions to reduce the metal oxide to pure metal or less reduced metal oxide. Optionally, a biocatalyst can also be supplied to the fourth heating vessel or heating zone, where the biocatalyst reacts with the metal oxide to form pure metal or less reduced metal oxide. In certain embodiments, the biocatalyst, rather than a reducing gas, is supplied to the fourth heating vessel or heating zone. As used herein, "less reduced metal oxide" refers to a metal oxide product that is partially reduced compared to the starting metal oxide reactant, but not as reduced as a zero-valent metal.

[0023] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are arranged sequentially in a continuous process.

[0024] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone operate in countercurrent flow with respect to the solid and gas phases.

[0025] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are each vertical, solids, downflow vessels.

[0026] In some embodiments, the dried biomass is pelleted prior to step (b). Alternatively or additionally, the biocatalyst can be pelleted prior to step (c).

[0027] In some embodiments, the biocatalyst is a 14 C / 12In a preferred embodiment, the biocatalyst is at least 90% reproducible as determined from measurements of the C isotope ratio. 14 C / 12 It is fully reproducible as determined from measurements of C isotope ratios.

[0028] In some embodiments, the biocatalyst contains at least about 50 wt% fixed carbon. In certain embodiments, the biocatalyst contains at least about 80 wt% fixed carbon.

[0029] In some embodiments, the biocatalyst is about 200 ml 2 / g~about 2000m 2 / g. The biocatalyst surface area is at least about 400 m 2 / g, at least about 800m 2 / g, or at least about 1200 m 2 In certain embodiments, the biocatalyst surface area can be about 500 m / g. 2 / g~about 1500m 2 / g.

[0030] In some embodiments, a portion of the reducing gas is combusted in a power generation unit to generate electricity, which can be used within the process or exported as an electrical by-product.

[0031] Another variation provides a process for producing carbon negative hydrogen and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing (i) a reducing gas comprising H and CO, and (ii) activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H2 and the activated carbon from a third heated vessel or heated zone, wherein the H2 is carbon-negative hydrogen characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0032] In some embodiments, the first portion of the biogas is fed to a third heating vessel or heating zone. In other embodiments, the biogas is not fed to a third heating vessel or heating zone.

[0033] In some embodiments where a portion of the biogas is fed to a third heating vessel or heating zone, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of the biogas, where the biocatalytic conversion of the biogas is catalyzed by a biocatalyst. There can also be non-catalytic / homogeneous biocatalytic conversion of the biogas, or biocatalytic conversion catalyzed by ash or metals present on the reactor walls or in the stream.

[0034] In some embodiments, the effective biocatalytic conversion conditions in step (c) cause the biocatalytic conversion of the biocatalyst.

[0035] In some embodiments, the effective biocatalytic conversion conditions in step (c) result in the biocatalytic conversion of the biocatalyst as well as the biocatalytic conversion of the biogas. The biocatalytic conversion of the biogas can be catalyzed by the biocatalyst prior to conversion to a reduced gas.

[0036] In some embodiments, the process further comprises recovering a portion of the biocatalyst as a biogenic carbon by-product, wherein the biogenic carbon by-product produced in step (b) is different from the activated carbon produced in step (c).

[0037] At least a portion of the activated carbon can be recycled to the first heating vessel or heating zone, the second heating vessel or heating zone, the inlet of the third heating vessel or heating zone, or combinations thereof.

[0038] In some embodiments, the process further includes separating a second recovered water stream from the biogas (e.g., using a condenser). If a portion of the biogas is fed to a third heating vessel or heating zone, the second recovered water stream can be fed to the third heating vessel or heating zone to perform biocatalytic conversion of the biogas. Alternatively or additionally, the second recovered water stream can be fed to a third heating vessel or heating zone to perform biocatalytic conversion of the biocatalyst. Alternatively or additionally, the second recovered water stream can be fed to a third heating vessel or heating zone to perform water-gas shift of CO to produce additional H.

[0039] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are one common physical unit that is reused in steps (a), (b), and (c).

[0040] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are arranged sequentially in a continuous process.

[0041] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone operate countercurrently to the solid and gas phases, respectively.

[0042] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each vertical, solids, downflow vessels.

[0043] In some embodiments, the first heating vessel or heating zone contains a substantially inert gas. In some embodiments, the second heating vessel or heating zone contains a substantially inert gas. In certain embodiments, the second heating vessel or heating zone contains less than 0.1 vol% oxygen.

[0044] In some embodiments, the first heating vessel or heating zone operates at a drying temperature of about 100°C to about 400°C. In some embodiments, the second heating vessel or heating zone operates at a pyrolysis temperature of about 300°C to about 900°C. In some embodiments, the third heating vessel or heating zone operates at a biocatalytic conversion temperature of about 600°C to about 1200°C.

[0045] In some embodiments in which the first portion of the biogas is supplied to a third heating vessel or heating zone, step (c) achieves a conversion of the biogas to reducing gas of at least 50% or at least 90%, where the conversion is calculated based on the biogas entering the third heating vessel or heating zone.

[0046] In some embodiments, step (c) achieves at least 25% or at least 50% conversion of biocatalyst to reducing gas, where this conversion is calculated based on the biocatalyst entering the third heated vessel or heated zone.

[0047] In some embodiments, at least a portion of the CO is recycled within the process. CO recycling can enhance the extent of the water-gas shift reaction, thereby making it available, for example, to produce additional H from CO and HO.

[0048] In some embodiments, CO2 is produced in step (c), and at least a portion of the CO2 is recycled within the process. CO2 recycling can be performed to reduce the reactivity of the environment in the previous step, such as in a first heating vessel or heating zone. CO2 recycling can be performed to increase the steam velocity in the previous step. CO2 recycling can improve the extent of the dry reforming reaction, thereby being utilized to produce additional H2 from CO2 and hydrocarbons (e.g., pyrolysis oil). CO2 can be used to drive dry reforming of biogas or biocatalysts to produce additional reducing gas.

[0049] In some embodiments, the carbon intensity of carbon-negative hydrogen is less than -3,000 kg COe per metric ton of H. In particular embodiments, the carbon intensity of carbon-negative hydrogen is less than -10,000 kg COe per metric ton of H.

[0050] In some embodiments, the activated carbon is assigned a carbon strength of less than 0 kg CO2e per metric ton of activated carbon. In certain embodiments, the activated carbon has a carbon strength of less than -1,000 kg CO2e per metric ton of activated carbon.

[0051] In some embodiments, the process is a water-positive process characterized by a net water production of greater than 0 kg HO per kg H. The net water production can be, for example, at least 3 kg HO per kg H, or at least 6 kg HO per kg H. In preferred embodiments of a water-positive process, no water is added to the process. Rather, the process utilizes water that enters with the biomass and water produced in chemical reactions during pyrolysis of the biomass.

[0052] In some embodiments, the process further includes supplying the metal oxide and H or CO to a fourth heated vessel or heating zone operating under effective metal oxide reducing conditions to reduce the metal oxide to pure metal or less reduced metal oxide. Optionally, a biocatalyst can also be supplied to the fourth heated vessel or heating zone such that the biocatalyst reacts with the metal oxide to support the formation of pure metal or less reduced metal oxide.

[0053] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are arranged sequentially in a continuous process.

[0054] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone operate in countercurrent flow with respect to the solid and gas phases.

[0055] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are each vertical, solids, downflow vessels.

[0056] In some embodiments, the dried biomass is pelleted prior to step (b). In these or other embodiments, the biocatalyst is pelleted prior to step (c).

[0057] In some embodiments, the activated carbon is pelletized after step (f)m, regardless of whether any material was pelletized earlier in the process.

[0058] In some embodiments, the biocatalyst is a 14 C / 12In certain embodiments, the biocatalyst is at least 90% reproducible as determined by measuring the C isotope ratio. 14 C / 12 It is fully reproducible as determined from measurements of C isotope ratios.

[0059] In some embodiments, the activated carbon is 14 C / 12 In certain embodiments, the activated carbon is at least 90% renewable as determined from measurements of the C isotope ratio. 14 C / 12 It is fully reproducible as determined from measurements of C isotope ratios.

[0060] In some embodiments, the biocatalyst contains at least about 50 wt% fixed carbon, eg, at least about 80 wt% fixed carbon.

[0061] In some embodiments, the activated carbon contains at least about 60 wt% fixed carbon, eg, at least about 90 wt% fixed carbon.

[0062] In some embodiments, the biocatalyst is about 200 ml 2 / g~about 2000m 2 / g. In various embodiments, the biocatalyst surface area is at least about 400 m 2 / g, at least about 800m 2 / g, or at least about 1200 m 2 In certain embodiments, the biocatalyst surface area is about 500 m 2 / g~about 1500m 2 / g.

[0063] In some embodiments, the activated carbon is about 400 ml 2 / g~about 4000m 2 / g. The activated carbon surface area is at least about 500 m 2 / g or at least about 750m 2In certain embodiments, the activated carbon surface area can be about 500 m / g. 2 / g~about 1000m 2 / g.

[0064] In some embodiments, a portion of the reducing gas is combusted in a power generation unit to generate electricity, which can be used in the process, exported to the power grid, or otherwise sold, or a combination thereof.

[0065] Another variation provides a process for producing a carbon negative reducing gas and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing a reduced gas and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering the reducing gas and activated carbon from the third heated vessel or heated zone, wherein the reducing gas is a carbon negative reducing gas characterized by a carbon intensity of less than 0 kg COe per metric ton of reducing gas.

[0066] Another variation provides a process for producing carbon negative CO and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing CO, H, and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering CO and activated carbon from the third heated vessel or heated zone, wherein the CO is carbon negative carbon monoxide characterized by a carbon intensity of less than 0 kg CO2e per metric ton of CO.

[0067] In some variations, the carbon negative hydrogen product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating under effective biocatalytic conversion conditions and water-gas shift conditions, thereby producing H and CO; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H from the third heated vessel or heated zone, wherein the H is carbon-negative hydrogen characterized by a carbon intensity of less than 0 kg COe per metric ton of H.

[0068] In some variations, the activated carbon product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing a reduced gas and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering the activated carbon from the third heating vessel or heating zone, wherein the activated carbon is assigned a carbon intensity of less than 0 kg CO2e per metric ton of activated carbon.

[0069] Another variation of the present invention provides a system for producing carbon-negative hydrogen, the system comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and a biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; a third heating vessel or heating zone configured to (i) receive a biocatalyst, (ii) optionally receive a first portion of the biogas, and (iii) produce H and CO, the third heating vessel or heating zone being in fluid communication with the second heating vessel or heating zone and comprising means for recovering H; a thermal oxidizer configured to oxidize at least a portion of the biogas to generate heat, the thermal oxidizer in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated and capable of producing carbon-negative hydrogen, characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0070] In some systems, a third heating vessel or heating zone is configured to receive the first portion of the biogas and convert a portion of the biogas to H2 and CO.

[0071] The system may further comprise a separation unit configured to separate the second recovered water stream from the biogas. The third heating vessel or heating zone may comprise an inlet for receiving the second recovered water stream.

[0072] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are spatially arranged sequentially such that operation of the system is sequential.

[0073] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate countercurrently with respect to the solid and gas phases, respectively.

[0074] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical, solids, downflow vessel.

[0075] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone each comprise an internal vessel lining.

[0076] The system may further include a fourth heating vessel or heating zone configured to reduce the metal oxide to pure metal or a less reduced metal oxide using H or CO. Alternatively or additionally, the fourth heating vessel or heating zone may be configured to reduce the metal oxide to pure metal or a less reduced metal oxide using a biocatalyst. In such a system, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone may be spatially arranged sequentially to enable operation of the system to operate sequentially.

[0077] The system can further include a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

[0078] The system may further include a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

[0079] In some systems, a power generation unit is configured to combust a portion of the biogas to generate electricity, and the power generation unit can be configured to power components in the system that require a power source.

[0080] Yet another variation provides a system for producing carbon negative hydrogen and activated carbon, the system comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and a biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; a third heating vessel or heating zone configured to (i) receive a biocatalyst, (ii) optionally receive a first portion of the biogas, and (iii) produce H, CO, and activated carbon, the third heating vessel or heating zone in fluid communication with the second heating vessel or heating zone, the third heating vessel or heating zone comprising a means for recovering H, and comprising a means for recovering the activated carbon; a thermal oxidizer configured to oxidize a second portion of the biogas to generate heat, the thermal oxidizer in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated and capable of producing carbon-negative hydrogen, characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0081] In some systems for producing both hydrogen and activated carbon, a third heating vessel or heating zone is configured to receive a first portion of the biogas and convert a portion of the biogas to H and CO.

[0082] In some systems for producing both hydrogen and activated carbon, the system can further include a separation unit configured to separate the second recovered water stream from the biogas. The third heating vessel or heating zone can be configured with an inlet for receiving the second recovered water stream.

[0083] In some systems for producing both hydrogen and activated carbon, a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone are spatially arranged sequentially to allow operation of the system to operate sequentially.

[0084] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate countercurrently to the solid and gas phases, respectively.

[0085] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical, solids, downflow vessel.

[0086] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone each comprise an internal vessel lining.

[0087] In some systems for producing both hydrogen and activated carbon, the system can further include a fourth heating vessel or heating zone configured to reduce metal oxides to pure metals or less reduced metal oxides using H or CO. Alternatively, or additionally, the fourth heating vessel or heating zone can be configured to reduce metal oxides to pure metals or less reduced metal oxides using a biocatalyst. In such systems, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone can be spatially arranged sequentially to enable operation of the system to operate sequentially.

[0088] In some systems for producing both hydrogen and activated carbon, the system may further include a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

[0089] In some systems for producing both hydrogen and activated carbon, the system may further include a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

[0090] In some systems for producing both hydrogen and activated carbon, a power generation unit is configured to combust a portion of the biogas to generate electricity, which can be configured to power components in the system that require a power source. [Brief explanation of the drawings]

[0091] [Figure 1] 1 is a simplified block flow diagram of a process for converting biomass feedstock to carbon-negative hydrogen and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units. [Figure 2] 1 is a simplified block flow diagram of a process for converting biomass feedstock into a carbon-negative reducing gas and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units. [Figure 3] FIG. 1 is a simplified block flow diagram of a process for converting biomass feedstock to carbon-negative CO and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units. [Figure 4] 1 is a simplified block flow diagram of a process for converting biomass feedstock into carbon-negative hydrogen using biocatalytic conversion and water-gas shift, according to some embodiments. Dotted lines indicate optional streams and units. DETAILED DESCRIPTION OF THE INVENTION

[0092] This specification describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, enabling one skilled in the art to make and use the disclosed disclosure. These and other embodiments, features, and advantages of the present disclosure will become more apparent to those skilled in the art from a reading of the following detailed description taken in conjunction with the accompanying drawings.

[0093] To enable technical disclosure, various explanations, hypotheses, theories, speculations, assumptions, etc. are disclosed. This disclosure does not assume that any of these are actually true. The explanations, hypotheses, theories, speculations, or assumptions in this detailed description are not to be construed in any way as limiting the scope of the disclosure.

[0094] Moreover, the headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed embodiments.

[0095] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, anywhere a product is produced, the process can be controlled to produce more than a single product; for example, where a "carbon-metal ore particulate" is produced, a "plurality of carbon-metal ore particulates" can be produced. This is also true for compositions including a single component. For example, where a composition includes a carbon-metal ore particulate, the composition can include a plurality of carbon-metal ore particulates.

[0096] Unless otherwise indicated, all numbers expressing reaction conditions, stoichiometries, concentrations of ingredients, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations that can vary depending, at least on particular analytical techniques.

[0097] As used herein, the term "about" means ±20% of the indicated range, value, or structure, unless otherwise indicated.

[0098] As described herein, any concentration range, percentage range, ratio range, or integer range should be understood to include any integer value within the recited range, and fractions thereof (such as integer tenths and hundredths), where appropriate, unless otherwise indicated. Also, any numerical range described herein is understood to include any integer within the recited range, unless otherwise indicated.

[0099] As used herein, "ranging from about or a range therebetween," for example, "ranging from about X, Y, or Z or a range therebetween," includes "at least X up to Z."

[0100] As used herein, "biogenic" refers to materials (feedstocks, products, or intermediates) containing elements such as carbon that are renewable over time scales of months, years, or decades. Non-biogenic materials can be non-renewable or renewable over geological time scales of centuries, thousands, millions, or even longer. For example, traditional fuel sources, such as coal and petroleum, are non-renewable and not biologically derived. Biogenic materials consist essentially of biological sources. Those skilled in the art will understand that naturally sourced or naturally derived biogenic materials can contain trace amounts of non-biogenic materials. Furthermore, the processes disclosed herein can be used with non-biogenic materials, although with less significant beneficial environmental impact.

[0101] 12 C. 13 C. 14 There are three naturally occurring isotopes of carbon, C. 12 C and 13 C is stable and exists in a natural ratio of about 93:1. 14C is produced by thermal neutrons from cosmic radiation in the upper atmosphere, transported to Earth, and absorbed by biological materials. 14 Although C accounts for a very small proportion, it is radioactive with a half-life of 5,700 years and can therefore be detected by radiometric measurements. 14 Because it does not absorb C, 14 The amount of C is one of the methods used for radiometric dating of biological material.

[0102] Plants fix carbon from the atmosphere through photosynthesis 14 Animals absorb C when they eat plants or other animals that eat plants. 14 C into their bodies. Therefore, living plants and animals 14 C and 12 The ratio of carbon to carbon dioxide is the same as that of atmospheric CO2. When an organism dies, the exchange of carbon with the atmosphere stops, and therefore new carbon dioxide is released. 14 After that, radioactive decay occurs in the organism. 14 C gradually decreases. This effect is the basis of radiocarbon dating.

[0103] Fossil fuels such as coal are primarily made from plant matter deposited millions of years ago. 14 Since it is several thousand times the half-life of C, 14 The carbon dioxide has virtually completely decayed. Fossil fuels were also originally produced by living organisms, so they are less dense than the atmosphere. 13 C is depleted. Therefore, carbon from fossil fuels is less available than carbon from living organisms. 13 C and 14 Both C are depleted.

[0104] This difference between the carbon isotopes of recently extinct organic matter, such as renewable resources, and the carbon isotopes of fossil fuels, such as coal, allows one to determine the source of the carbon in a composition, specifically whether the carbon in the composition was obtained from a renewable resource or a fossil fuel, or in other words, whether a renewable resource or a fossil fuel was used to produce the composition.

[0105] Biomass is a term used to describe biologically produced or living matter. Biomass refers to the mass of living organisms, such as plants, animals, and microorganisms, or, from a biochemical perspective, cellulose, lignin, sugars, fats, and proteins. Biomass includes both above-ground and underground plant tissues, such as leaves, twigs, branches, and stems, as well as the roots of trees and rhizomes of grasses. The chemical energy contained in biomass is obtained from solar energy using the natural process of photosynthesis, in which plants absorb carbon dioxide and water from their surroundings and use energy from sunlight to convert them into sugars, starch, cellulose, hemicellulose, and lignin. Biomass is useful because it essentially stores solar energy. Biomass is the only renewable carbon source.

[0106] As used herein, the term "comprising" is synonymous with "including," "containing," or "characterized by" and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. "Comprising" is a term of the art used in claim language to indicate that a specified claim element is essential, but that other claim elements can be added and still form a structure within the scope of the disclosure. "Comprising" also provides a basis for "consisting of" or "consisting essentially of." For example, if a formulation "comprises X, Y, Z," the formulation can consist of X, Y, Z, or consist essentially of X, Y, Z.

[0107] As used herein, "consisting of" excludes any element, step, or ingredient not specified. When the phrase "consists of" appears in a clause in the body of a claim rather than immediately following the preamble, the phrase "consists of" limits only the elements recited in that clause and does not exclude other elements from the claim as a whole. As used herein, the phrase "consisting essentially of" limits the claim to the specified elements or method steps and those that do not essentially affect the claimed subject matter.

[0108] As used herein, a "derivative" is a compound, molecule, or ion obtained from another substance by chemical reaction.

[0109] As used herein, "high carbon," as in "high carbon biogenic reagent," indicates that the biogenic reagent has a higher carbon content than the feedstock used to produce the high carbon biogenic reagent. A high carbon biogenic reagent can contain at least about half of its weight in carbon. For example, a high carbon biogenic reagent can contain at least about 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 wt% carbon, or any number in between.

[0110] As used herein, "high-carbon biogenic reagent" describes a material that can be produced by the disclosed processes and systems. No limitations on carbon content or any other concentration should be implied by the term itself, but only with reference to specific embodiments. For example, when a low-carbon feedstock is subjected to the disclosed processes, the product is a high-carbon biogenic reagent that is very rich in carbon (high carbon yield) compared to the starting material, but still has a relatively low carbon content (low carbon purity), containing up to about 50 wt% carbon.

[0111] As used herein, the terms "include," "having," and "comprise" are used interchangeably and such terms and variations are intended to be interpreted as open-ended.

[0112] As used herein, a "metal ore" is a metal-containing material in which the desired metal is not present in pure elemental form, but rather as a metal oxide, metal sulfide, metal nitride, metal carbide, metal boride, metal phosphide, or another form of the metal.

[0113] The use of the word "or" in connection with a list of two or more items encompasses all of the following interpretations of that word: any of the items in the list, all of the items in the list, and any combination of the items in the list. Furthermore, the phrase "at least one of A, B, and C, etc." is intended in the sense that one of ordinary skill in the art would understand that convention. For example, "a system having at least one of A, B, and C" includes, but is not limited to, A only, B only, C only, A and B together, A and C together, B and C together, or A, B, and C together, etc. In instances where a convention similar to "at least one of A, B, or C, etc." is used, such construction is generally intended in the sense that one of ordinary skill in the art would understand that convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, or A, B, and C together, etc.).

[0114] As used herein, "pellets" is synonymous with "briquettes" and can refer to pellets, briquettes, pellet / briquettes, or similar terms, all of which refer to agglomerated bodies rather than loose powders. For convenience, the term "pellets" is used generically. The geometry of pellets is not limited to spherical or nearly spherical. The geometry of pellets can be spherical (round or ball-shaped), cubic (square), octagonal, hexagonal, honeycomb / honeycomb, elliptical, oval, cylinder-shaped, rod-shaped, loaf-shaped, pillow-shaped, random, or a combination thereof.

[0115] As used herein, "pyrolysis" is the thermal decomposition of a carbonaceous material. In pyrolysis, less oxygen is present than is required for complete combustion of the material, such as up to about 10%, 5%, 1%, 0.5%, 0.1%, or 0.01% of the amount of oxygen (on an O2 molar basis) required for complete combustion. In some embodiments, pyrolysis is carried out in the absence of oxygen.

[0116] As used herein, a "reagent" is a material in the broadest sense. For example, a reagent can be a fuel, a chemical, a material, a compound, an additive, a blend component, or a solvent. A reagent is not necessarily a chemical reagent that causes or participates in a chemical reaction. However, a reagent can be a chemical reactant that can be consumed in a reaction. A reagent can be a chemical catalyst for a particular reaction. A reagent can cause or participate in adjusting the mechanical, physical, or hydrodynamic properties of a material to which it can be added. For example, a reagent can be introduced into a metal to give it particular strength properties. A reagent can be a substance of sufficient purity (in the present context, usually carbon purity) to be used for chemical analysis or physical testing.

[0117] As used herein, "renewable hydrogen" does not take into account the renewable nature of hydrogen contained in the water (HO) reactant, which can be used to react with carbon or CO to produce H, 2 H / 1It is determined by the correlation between the H isotope ratio and the recyclability of the starting material. 2 H / 1 The H isotope ratio correlates with the renewable potential of hydrogen, 2 H / 1 A higher H isotope ratio indicates a higher renewable hydrogen content.

[0118] As used herein, "total carbon" is the sum of fixed carbon and non-fixed carbon present in volatile matter. In some embodiments, component weight percentages are absolute values ​​and are assumed to be absolute unless otherwise specified. In other embodiments, component weight percentages are exclusive of moisture and ash.

[0119] As used herein, a "zone" is a region of space within a single physical unit, physically separated units, or any combination thereof. In the case of a continuous reactor, the division of zones can be related to structure, such as the presence of vanes within the reactor or the presence of separate heating elements to provide heat to separate zones. Alternatively or additionally, the division of zones in a continuous reactor can be related to functions such as different temperatures, fluid flow patterns, solid flow patterns, or extent of reaction. In the case of a single batch reactor, a "zone" is an operating region in time, not space. A sharp transition from one zone to another is not required. For example, the boundary between the preheating zone and the pyrolysis zone can be somewhat arbitrary; some pyrolysis can occur in part of the preheating zone, and some "preheating" can continue to occur in the pyrolysis zone. The temperature profile within the reactor is typically continuous, including the zone boundaries within the reactor.

[0120] Both carbon and hydrogen have traditionally been produced from fossil feedstocks. Fossil feedstocks include natural gas, oil, coal, and lignite. Historically, carbon in the form of charcoal has been produced by the slow pyrolysis of large amounts of wood in a simple batch process with no emissions controls. Traditional charcoal production technologies are energy inefficient and highly polluting. Historically, hydrogen has been produced by steam reforming of natural gas. Due to the increasing economic, environmental, and social costs associated with fossil feedstocks, renewable resources have become attractive alternatives to fossil sources for the production of both carbon and hydrogen.

[0121] Hydrogen is used in a variety of industrial applications, including hydrogen vehicles, power generation, fertilizer production, metal alloying, glass production, and electronic processes such as vapor deposition, cleaning, etching, and reduction. Hydrogen is typically diatomic H2, a vital molecule that contains only two electrons and two protons, and no neutrons. Essentially, H2 is a carrier of electrons and protons, making it useful in many chemical reactions.

[0122] Hydrogen is used to process crude oil into refined fuels such as gasoline and diesel, and to remove contaminants such as sulfur from these fuels. In recent years, the use of hydrogen in refineries has increased due to stricter regulations requiring reduced sulfur content in diesel and the growing consumption of lower-quality crude oil, which requires more hydrogen for refining. While refineries produce some hydrogen as a by-product from catalytic reforming of naphtha, this supply only partially meets the refinery's hydrogen demand. Currently, approximately 80% of the hydrogen consumed by refineries worldwide is supplied by large-scale hydrogen plants that produce non-renewable hydrogen from natural gas or other hydrocarbon fuels.

[0123] Renewable hydrogen will be a key input in many emerging biorefineries. For example, when producing chemicals and fuels from biomass, hydrogen is stoichiometrically required to chemically remove oxygen and hydrogenate carbon-carbon double bonds.

[0124] Traditionally, hydrogen is produced by steam methane reforming, which consumes large amounts of fossil fuels and emits large amounts of carbon dioxide (CO2). As a result, hydrogen is carbon-intensive. Alternatively, hydrogen can be produced by the electrolysis of water. While renewable sources of electricity (e.g., solar or wind) can be used to power the electrolysis, large amounts of high-quality water are required to electrolyze water and produce hydrogen.

[0125] In view of the above needs, there is a commercial need for improved processes and systems for producing renewable hydrogen for other industrial applications, particularly where it is desirable for the hydrogen to be simultaneously carbon negative and water positive.

[0126] Some variations provide a process for producing carbon negative hydrogen and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing (i) a reducing gas comprising H and CO, and (ii) activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H2 and activated carbon from the third heated vessel or heated zone, wherein the H2 is carbon-negative hydrogen characterized by a carbon intensity of less than 0 kg CO2e per meter of H2.

[0127] As used herein, a "biocatalyst" is defined as a carbonaceous material that catalyzes the biocatalytic conversion of biogas to a reduced gas. Biocatalyst does not refer to enzymes, yeast, or bacteria for fermentation or enzymatic reactions. In some embodiments, the biocatalyst itself is consumed by the biocatalytic conversion or other reaction simultaneously with or subsequently to catalyzing the biocatalytic conversion of biogas. In other embodiments, the biocatalyst is not consumed but is activated, such as through dehydration, condensation, polymerization, carbonization, or oxidation, thereby converting the biocatalyst to activated carbon.

[0128] In some embodiments, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of biogas, said biocatalytic conversion of biogas being catalyzed by a biocatalyst. There can also be, for example, non-catalytic / homogeneous biocatalytic conversion of biogas, or biocatalytic conversion catalyzed by ash or metals present on the reactor walls or in the stream.

[0129] In some embodiments, the effective biocatalytic conversion conditions in step (c) cause biocatalytic conversion of the biocatalyst. In certain embodiments, the effective biocatalytic conversion conditions in step (c) cause biocatalytic conversion of the biocatalyst as well as biocatalytic conversion of the biogas when the first portion of the biogas is provided to the third heating vessel or heating zone. The biocatalytic conversion of the biogas (if present in the third heating vessel or heating zone) can be catalyzed by the biocatalyst before conversion to reduced gas or before conversion to activated carbon. Note that with respect to the reduced gas production reaction of a solid biocatalyst, "biocatalytic conversion" can be gasification in which gas (H and CO) is produced from the solid (biocatalyst).

[0130] In some embodiments, the biocatalytic conversion conditions result in a water-gas shift, i.e., HO + CO → H + CO. The water-gas shift reaction can be thought of as a biocatalytic conversion of CO. In this reaction, upon complete conversion, all of the hydrogen contained in the water molecule is converted to H. The water-gas shift reaction can be catalyzed by the biocatalyst or by another catalyst that is present.

[0131] As a skilled chemist or chemical engineer will appreciate, there is typically a complex reaction network that includes kinetically controlled reactions, equilibrium-limited reactions, catalytic mechanisms that can be rate-limited or mass-transfer limited, etc. These phenomena are always true in catalytic reactions. A further complication in this technology is that the biocatalyst not only catalyzes a specific reaction, but also participates in chemical reactions to produce hydrogen, converting hydrogen atoms within the biocatalyst to H2. Additionally or alternatively, the biocatalyst can undergo chemical and physical changes associated with carbon activation to produce activated carbon from the biocatalyst.

[0132] Without being limited by theory, the inventors have discovered that this additional integration is in fact a feature of the present technology. When steam is injected into a third heating vessel or heating zone along with the biogas, there are few or no vapor-phase mass transfer limitations. Homogeneous biocatalytic conversion can begin almost immediately. In the case of catalytic biocatalytic conversion, the reactants (biogas and water) diffuse to the biocatalyst surface, are adsorbed, and react on the surface to produce H2 and CO, which are released back into the vapor phase. The overall rate of biogas biocatalytic conversion is faster than that of biocatalytic conversion, which generally requires breaking more bonds within the biocatalyst than biogas conversion. Furthermore, because biocatalytic conversion typically occurs primarily on the biocatalyst surface, the biocatalyst becomes a shrinking particle reactor, with an overall rate that depends on particle size. As a result, for a given temperature and pressure, biocatalytic conversion of biogas is almost always faster than gasification of the biocatalyst itself. This means that the biocatalyst does a relatively quick job of catalyzing the biogas conversion to H2 and CO, and then is essentially consumed to produce H2 / CO or activated carbon, all within the same reactor (third heated vessel or heated zone).

[0133] Various components of H and CO in the reduced gas can be produced by biogas conversion and biocatalytic conversion. At least a portion of the H and CO is produced by biocatalytic conversion. In some embodiments, biogas conversion to H and CO is not performed in the third heating vessel or heating zone, in which case all of the H and CO is produced by biocatalytic conversion. A mass balance can determine or estimate the origin of the H, C, and O atoms in the reduced gas. Typically, some of the H comes from the initial biomass moisture, HO, or water released during pyrolysis in the second heating vessel or heating zone. The carbon atoms in CO come from carbon contained in the biocatalyst or biogas. The oxygen atoms in CO come from oxygen in HO and potentially from oxygenated biocatalyst or biogas components (e.g., acetic acid). Ultimately, unless there are some other carbon-containing inputs to the process, all of the carbon in the CO comes from the biomass. The oxygen (in CO) and hydrogen (in H) are stoichiometrically derived from both HO and biomass, with the biomass being C for the main cellulose, hemicellulose, and lignin components. x H y O z It can be simply expressed as:

[0134] In various embodiments, about 0 wt% to about 95 wt% of the reducing gas product is obtained from biogas, while about 100 wt% to about 5 wt% of the reducing gas is obtained directly from the biocatalyst. In some embodiments, about, at least about, or up to about 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 95 wt% of the reducing gas product is obtained from biogas. In some embodiments, about, at least about, or up to about 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or 100 wt% of the reducing gas product is obtained from the biocatalyst.

[0135] In some embodiments, about 0 wt% to 95 wt% of the H2 product is obtained from biogas or water consumed in biogas conversion, while 100 wt% to about 5 wt% of the H2 is obtained directly from the biocatalyst or water consumed in the biocatalytic conversion. In some embodiments, about, at least about, or up to about 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 95 wt% of the H2 product is obtained from the biogas or water consumed in the biogas conversion. In some embodiments, about, at least about, or up to about 5, 10, 20, 30, 40, 50, 60, 70, 80, 85, 90, 95, or 100 wt% of the H2 product is obtained from the biocatalyst or water consumed in the biocatalytic conversion. The term "water consumed in the biocatalytic conversion" can be understood in simplified reference to a model biocatalyst that is pure carbon (C). The biocatalytic conversion of this biocatalyst can be represented as C + H2O → H2 + CO. The H2 product molecule is formally derived from the water molecule that is completely consumed in the biocatalytic conversion. Thus, in this example, the H2 product is obtained from reactant C.

[0136] In some embodiments, about 0 wt% to 95 wt% of the CO2 product is obtained from biogas or water consumed in the biogas conversion, while 100 wt% to about 5 wt% of the CO2 is obtained directly from oxygen in the biocatalyst or water consumed in the biocatalyst conversion. In some embodiments, about, at least about, or up to about 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 95 wt% of the CO2 product is obtained from oxygen in the biogas or water consumed in the biogas conversion. In some embodiments, about, at least about, or up to about 5, 10, 20, 30, 40, 50, 60, 70, 80, 85, 90, 95, or 100 wt% of the CO2 product is obtained from the biocatalyst or water consumed in the biocatalyst conversion.

[0137] In various embodiments, the conversion rate of biogas to reducing gas in step (c) is about, or at least about, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 99%, 99.5%, 99.9%, or 100%, including all intermediate ranges. This conversion rate is calculated based on the biogas entering the third heating vessel or heating zone. Note that if biogas is not supplied from the second heating vessel or heating zone to the third heating vessel or heating zone, at least a small amount of biogas (e.g., methane) is typically produced from the biocatalyst in the third heating vessel or heating zone. In this case, the biogas conversion rate within the third heating vessel or heating zone can be calculated and can be within the above-mentioned 50-100% range. If biogas is not supplied to or produced within the third heating vessel or heating zone, the conversion rate of biogas to reducing gas cannot be mathematically calculated within that vessel (0 / 0 is undefined).

[0138] Typically, when activated carbon is produced and recovered, it is produced from solid carbon within the biocatalyst. A small amount of biogas coking or CO coking may occur, in which case coke may deposit on the surface or in the pores of the biocatalyst. In this scenario, the coke may remain as the carbon content of the final activated carbon, and the deposited coke may or may not adversely affect the surface area of ​​the activated carbon.

[0139] Typically, all of the carbon in the activated carbon comes from the biocatalyst, but this does not mean that all of the biocatalyst becomes activated carbon. As mentioned above, a portion of the biocatalyst is typically converted to a reducing gas. Also, a portion of the biocatalyst is not converted or activated and functions as a catalyst, but can then pass to the outlet of the third heating vessel or heating zone as non-activated carbon.

[0140] In various embodiments, the conversion of biocatalyst to reducing gas in step (c) is about, at least about, or at most about 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 99%, 99.5%, 99.9%, or 100%, including all intermediate ranges, calculated based on the biocatalyst entering the third heated vessel or zone.

[0141] In various embodiments, the conversion of biocatalyst to activated carbon in step (c) is about, at least about, or at most about 0%, 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, or 99%, including all intermediate ranges.

[0142] In various embodiments, the conversion of biocatalyst to the sum of (reducing gas + activated carbon) in step (c) is about, at least about, or at most about 50%, 60%, 70%, 80%, 85%, 90%, 95%, 99%, 99.5%, 99.9%, or 100%, including all intermediate ranges.

[0143] The biocatalyst conversion rates in the preceding three paragraphs are conversion rates within the third heating vessel or heating zone only, without biocatalyst recycling. If biocatalyst is recycled, e.g., fed to a second heating vessel or heating zone, some amount of biocatalyst can be converted to reducing gas or activated carbon within the second heating vessel or heating zone, when the biocatalyst conversions listed above are gross (net) conversions.

[0144] In the third heating vessel or heating zone, the biocatalyst is ultimately converted into reducing gas, activated carbon, by-products (e.g., tar), or remains unconverted. Simultaneously with these reactions, the biocatalyst can catalyze biogas (supplied from the second heating vessel or heating zone or internally generated within the third heating vessel or heating zone) to produce reducing gas. While catalyzing the production of reducing gas from biogas, the biocatalyst undergoes chemical changes, such as surface functionalization (e.g., generation of -COOH groups), or physical changes, such as increased surface area and porosity. In most chemical reactors, physical or chemical changes to the catalyst are undesirable and cause catalyst fouling or deactivation. In this technology, after catalyzing the reaction, the catalyst is utilized as a reactant to produce useful products in itself, i.e., more biogas and activated carbon. In this sense, the biocatalyst delivers a "triple play" by catalyzing the biogas chemical reaction to produce reducing gas, serving as a reaction matrix to produce reducing gas from itself, and ultimately becoming activated carbon, a useful product in itself.

[0145] Optionally, the process can further include recovering a portion of the biocatalyst as a biogenic carbon by-product prior to producing activated carbon. This option is illustrated in Figures 1-4 as a dotted arrow below the second heating vessel or heating zone, where some biocatalyst can be removed rather than being transported to a third heating vessel or heating zone. Because some biocatalyst is required in the third heating vessel or heating zone to catalyze the biocatalytic conversion of biogas and, optionally, to produce activated carbon, removing all of the biocatalyst at this point is not preferred. Notwithstanding the foregoing, those skilled in the art will recognize that it is conceptually possible to provide a different source or amount of biocatalyst to the third heating vessel or heating zone while removing all of the biocatalytic material discharged from the second heating vessel or heating zone.

[0146] In some embodiments, at least a portion of the activated carbon is recycled back to the first heating vessel or heating zone, recycled back to the second heating vessel or heating zone, recycled back to the inlet of the third heating vessel or heating zone, or a combination thereof. Without being limited by theory, potential reasons for recycling activated carbon are varied. In some embodiments, activated carbon is recycled to increase the final production of reducing gas. In some embodiments, activated carbon is recycled to act as a filtration medium during the process, rendering the biogas or reducing gas cleaner. In some embodiments, activated carbon is recycled back to the first heating vessel or heating zone to facilitate drying of the biomass. In some embodiments, activated carbon is recycled to improve the properties of the biocatalyst, such as its function as a catalyst, its function as a reactant for producing reducing gas, its properties (e.g., microporosity) when removed as a by-product between the second heating vessel or heating zone and the third heating vessel or heating zone, or a combination thereof.

[0147] In some embodiments, the process further includes separating a second recovered water stream from the biogas (e.g., using a condenser). The second recovered water stream can be fed to a third heating vessel or heating zone for biocatalytic conversion of the biogas, biocatalytic conversion of a biocatalyst, water-gas shift of CO to produce additional H, or a combination thereof.

[0148] In embodiments in which the biogas does not pass from the second heating vessel or heating zone to a third heating vessel or heating zone, all of the biogas can be thermally oxidized in step (d). Alternatively, some but not all of the biogas can be thermally oxidized, with some biogas being removed for use for other purposes or sold to the market. Heat exchangers can be used to heat the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone by heating a physical vessel directly or via a heat exchanger configured to transfer heat to the incoming stream.

[0149] Step (d) typically utilizes combustion (complete oxidation) of biogas to produce useful heat, CO and HO. Alternatively, step (d) can utilize partial oxidation of biogas to produce heat, CO and H. In these embodiments, process heat is still generated and can be used to heat the first heating vessel or heating zone, the second heating vessel or heating zone, or the third heating vessel or heating zone. Optionally, the heated partial oxidation product can be fed directly to the third heating vessel or heating zone, as heat can be utilized directly (without the need for a heat exchanger) and the CO / H content can be recovered in the biogas product from the third heating vessel or heating zone.

[0150] In a typical process, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are arranged sequentially in a continuous process. In some processes, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are a single physical common unit reused in steps (a), (b), and (c). In certain embodiments, the first heating vessel or heating zone or the second heating vessel or heating zone is a single physical common unit reused in steps (a) and (b), while a physically different vessel is used in step (c). Similarly, in certain embodiments, the first heating vessel or heating zone or the third heating vessel or heating zone is a single physical common unit reused in steps (a) and (c), while a physically different vessel is used in step (b). Similarly, in certain embodiments, the second heating vessel or heating zone or the third heating vessel or heating zone is a common physical unit that is reused in steps (b) and (c), while a physically different vessel is used in step (a).

[0151] In some processes, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone operate countercurrently with respect to the solid and gas phases, respectively. The countercurrent flow can be ideally countercurrent or substantially countercurrent flow. In some embodiments, instead of or in addition to countercurrent flow, a cocurrent or crosscurrent flow exists within the first heating vessel or heating zone, the second heating vessel or heating zone, or the third heating vessel or heating zone.

[0152] In some processes, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each vertical, solids-downflow vessels. In certain embodiments, the first heating vessel or heating zone and the second heating vessel or heating zone are vertical, solids-downflow vessels, while the third heating vessel or heating zone has a different configuration. In certain embodiments, the second heating vessel or heating zone and the third heating vessel or heating zone are vertical, solids-downflow vessels, while the first heating vessel or heating zone has a different configuration. In certain embodiments, the first heating vessel or heating zone and the third heating vessel or heating zone are vertical, solids-downflow vessels, while the second heating vessel or heating zone has a different configuration. In certain embodiments, only one of the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone is a vertical, solids-downflow vessel.

[0153] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured with an internal vessel lining. In certain embodiments, the first heating vessel or heating zone and the second heating vessel or heating zone are configured with an internal vessel lining, while the third heating vessel or heating zone does not have an internal vessel lining. In certain embodiments, the second heating vessel or heating zone and the third heating vessel or heating zone are configured with an internal vessel lining, while the first heating vessel or heating zone does not have an internal vessel lining. In certain embodiments, the first heating vessel or heating zone and the third heating vessel or heating zone are configured with an internal vessel lining, while the second heating vessel or heating zone does not have an internal vessel lining. In certain embodiments, only one of the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone is configured with an internal vessel lining. The internal vessel lining can be, for example, a coating or a thick-walled internal shell.

[0154] The material of the inner vessel lining, if used, can be selected from ceramics (e.g., refractory ceramics), metals, metal alloys, metal oxides, metal carbides, metal nitrides, metal hydrides, carbon, glass, and combinations thereof. Exemplary materials for the inner vessel lining include, but are not limited to, silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxide, boron nitride, silicon carbide, titanium, titanium oxide, tungsten, nickel-based alloys, zirconium-based alloys, titanium-based alloys, stainless steel, graphite, graphene, diamond, glassy or vitreous carbon, or combinations thereof.

[0155] In some embodiments, the first heating vessel or heating zone contains a substantially inert gas. In these or other embodiments, the second heating vessel or heating zone contains a substantially inert gas. The inert gas in the first heating vessel or heating zone can be the same as or different from the inert gas in the second heating vessel or heating zone. In some embodiments, the second heating vessel or heating zone contains less than 0.1 vol% oxygen to avoid oxidation of the biocatalyst or biogas in the second vessel or zone.

[0156] The first heated vessel or heating zone can operate at a drying temperature of, for example, about 100° C. to about 400° C. In various embodiments, the first heated vessel or heating zone operates at a drying temperature of about, at least about, or up to about 100° C., 125° C., 150° C., 175° C., 200° C., 250° C., 300° C., 350° C., or 400° C., including all intermediate ranges.

[0157] The first heating vessel or heating zone can operate, for example, at a drying residence time of about 30 minutes to about 8 hours, hi various embodiments, the first heating vessel or heating zone operates at a drying residence time of about, at least about, or up to about 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, or 8 hours, including all intermediate ranges.

[0158] The first heating vessel or heating zone can be operated to achieve various moisture levels in the dried biomass. For example, the dried biomass can contain from 0 wt% to up to about 30 wt% moisture. In some embodiments, the dried biomass contains about 1-10 wt% moisture. In various embodiments, the dried biomass contains about, at least about, or up to about 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 wt% moisture, including all intermediate ranges.

[0159] A typical biomass feedstock enters the first heating vessel or heating zone at about 50 wt% moisture, which can vary widely. Dryness can be calculated as the ratio of influent water to biomass, as the percentage of water released into the recovered water stream. Dryness can be about 50% to 100%, e.g., about 75% to about 95%. In various embodiments, dryness is about, at least about, or up to about 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5%, or 100%, including all intermediate ranges.

[0160] The second heating vessel or heating zone can operate at a pyrolysis temperature of, for example, about 300° C. to about 900° C. In various embodiments, the second heating vessel or heating zone operates at a pyrolysis temperature of about, at least about, or up to about 300° C., 400° C., 500° C., 550° C., 600° C., 650° C., 700° C., 800° C., or 900° C., including all intermediate ranges. In certain embodiments, the pyrolysis temperature can exceed 900° C., such as when short pyrolysis times are used or when the characteristics of the dry biomass dictate that much higher pyrolysis temperatures be used.

[0161] The second heating vessel or heating zone can operate, for example, at a pyrolysis residence time of from about 15 minutes to about 8 hours. In various embodiments, the second heating vessel or heating zone operates at a drying residence time of about, at least about, or at most about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 2, 3, 4, 5, 6, 7, or 8 hours, including all intermediate ranges.

[0162] The third heating vessel or heating zone can operate at a biocatalytic conversion temperature of, for example, about 600° C. to about 1200° C. In various embodiments, the third heating vessel or heating zone operates at a biocatalytic conversion temperature of about, at least about, or up to about 600° C., 700° C., 750° C., 800° C., 850° C., 900° C., 950° C., 1000° C., 1100° C., or 1200° C., including all intermediate ranges. In certain embodiments, the biocatalytic conversion temperature can exceed 1200° C., for example, when short biocatalytic conversion times are used or when the characteristics of the biocatalyst dictate that much higher temperatures be used for the biocatalytic conversion.

[0163] In some embodiments, at least a portion of the CO produced in the third heating vessel or heating zone is recycled within the process. For example, CO recycle can be used to adjust the equilibrium or kinetics of a reaction network including CO, CO, C, H, and HO, e.g., to optimize the production of solid carbon and H. CO recycle can be used to improve the extent of the water-gas shift reaction, thereby producing additional H from CO and HO, e.g.

[0164] In some embodiments, CO2 is produced in step (c), and at least a portion of the CO2 is recycled within the process. CO2 recycling can be performed, such as in a first heating vessel or heating zone, to reduce the reactivity of the environment in the previous step. CO2 recycling can be performed to increase the steam rate in the previous step. CO2 recycling can be used to adjust the equilibrium or kinetics of a reaction network containing CO, CO2, C, H2, and H2O, e.g., to optimize the production of solid carbon and H2. For example, CO2 recycling can be used to improve the extent of dry reforming reactions, thereby producing additional H2 from CO2 and hydrocarbons (e.g., pyrolysis oil). In some embodiments, the recycled CO2 drives the dry reforming of biogas or biocatalysts to produce additional reducing gas.

[0165] Generally, to calculate the carbon intensity of a product, it is necessary to estimate not only the carbon intensity of the starting material, but also the carbon intensity associated with the conversion of the starting material to an intermediate, and the carbon intensity associated with the conversion of the intermediate to the final product. The known principles of life cycle assessment can be used to calculate the carbon intensity. Life cycle assessment (LCA) is a known method used to evaluate the environmental impact of a product throughout its entire life cycle, including the processing of raw materials, manufacture, distribution, use, recycling, and final disposal. When conducting an LCA, it is necessary to clarify the fate of the final product.

[0166] LCA can also take into account the current state of environmental inputs and outputs associated with a particular material. For example, unharvested forest residues decompose, releasing large amounts of methane gas as they decompose, resulting in significant greenhouse gas emissions. If these forest residues are used to produce biocarbon and then metals, the avoided methane emissions can be factored into the overall carbon intensity. Because so many possibilities exist and the current state itself is changing, it is advisable to utilize a database within the LCA software to ensure appropriate industry averages are adopted. LCA calculations can be supported by software such as GREET®, SimaPro®, or GaBi, or other LCA software. Unless otherwise specified, all carbon intensities described herein are assigned by mass according to the GREET® model and the latest database (see https: / / greet.es.anl.gov, which is incorporated by reference as of December 21, 2022).

[0167] In some processes, the carbon intensity of carbon-negative hydrogen is less than -3,000 kg CO2e per metric ton of H2. In certain processes, the carbon intensity of carbon-negative hydrogen is less than -10,000 kg CO2e per metric ton of H2.

[0168] For some processes, activated carbon is assigned a carbon intensity of less than 0 kg CO2e per metric ton of activated carbon. For certain processes, activated carbon has a carbon intensity of less than -1,000 kg CO2e per metric ton of activated carbon.

[0169] In some embodiments, the process further comprises step (g) of supplying the metal oxide and H or CO to a fourth heated vessel or heating zone operating under effective metal oxide reducing conditions to reduce the metal oxide to pure metal or less reduced metal oxide. A biocatalyst can also be supplied to the fourth heated vessel or heating zone, where the biocatalyst reacts with the metal oxide to form pure metal or less reduced metal oxide.

[0170] As used herein, "less reduced metal oxide" refers to a metal oxide product that is partially reduced relative to the starting metal oxide reactant, but not as reduced as the corresponding zero-valent metal. As an example and for illustration, during the conversion of FeO to FeO and then to Fe, FeO is a less reduced iron oxide compared to FeO, while Fe is the fully reduced metal. FeO can be reduced to FeO (or other intermediate iron oxides, such as FeO) using the reducing gases disclosed herein, or can be fully reduced to pure iron, Fe.

[0171] When a fourth heating vessel or heating zone is utilized, the first, second, third, and fourth heating vessels or zones can be arranged sequentially in a continuous process. Alternatively, the first, second, third, and fourth heating vessels or zones are a common physical unit that is reused in steps (a), (b), (c), and (g). In some processes, the first, second, third, and fourth heating vessels or zones operate countercurrently with respect to the solid and gas phases. In some processes, the first, second, third, and fourth heating vessels or zones are each vertical, solid-downflow vessels. The first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone and the fourth heating vessel or heating zone may each be configured with an internal vessel lining.

[0172] Any solids stream in the process can optionally be pelletized. In some embodiments, the dried biomass is pelletized before step (b). In these or other embodiments, the biocatalyst is pelletized before step (c). In some embodiments, the activated carbon is pelletized after step (f), i.e., after recovering the activated carbon from the third heating vessel or heating zone.

[0173] Any solids stream in the process can optionally be milled, crushed, or otherwise mechanically treated to reduce particle size. Such particle size reduction can be an initial step in pellet formation, or can be performed to increase surface area. As an example, biocatalyst recovered from the second heating vessel or heating zone can be crushed to reduce particle size and increase effective catalytic surface area.

[0174] In some processes, biocatalysis is 14 C / 12 In some embodiments, the biocatalyst is at least 90% reproducible as determined by measuring the C isotope ratio. 14 C / 12 In some embodiments, the biocatalyst is at least 99% renewable as determined by measuring the C isotope ratio of the biocatalyst. 14 C / 12 It is fully reproducible as determined from measurements of C isotope ratios.

[0175] In some processes, activated carbon is 14 C / 12 In some embodiments, the activated carbon is at least 85% renewable as determined from C isotope ratio measurements. 14 C / 12 In some embodiments, the activated carbon is at least 95% renewable as determined from measurements of C isotope ratios. 14 C / 12It is fully renewable as determined from C isotope ratio measurements. The renewable carbon content of activated carbon can differ from that of the biocatalyst because additives (e.g., pellet binders) can be introduced during the process between the production of the biocatalyst and the production of the activated carbon.

[0176] In some processes, the biocatalyst contains at least about 50 wt% fixed carbon, at least about 60 wt% fixed carbon, at least about 70 wt% fixed carbon, or at least about 80 wt% fixed carbon. In certain embodiments, the fixed carbon content of the biocatalyst can be very high, for example, at least about 85 wt%, at least about 90 wt%, at least about 95 wt%, or at least about 99 wt%.

[0177] In some processes, the activated carbon contains at least about 60 wt% fixed carbon, at least about 70 wt% fixed carbon, at least about 80 wt% fixed carbon, or at least about 90 wt% fixed carbon. In certain embodiments, the fixed carbon content of the activated carbon can be very high, for example, at least about 92 wt%, at least about 95 wt%, or at least about 99 wt%.

[0178] In some processes, biocatalysts are used for approximately 200 m 2 / g~about 2000m 2 / g. The biocatalyst surface area is at least about 400 m 2 / g, at least about 800m 2 / g, at least about 1200m 2 / g or at least about 1600m 2 In certain embodiments, the biocatalyst surface area can be about 500 m / g. 2 / g~about 1500m 2 / g.

[0179] In some processes, activated carbon is used for approximately 400 m 2 / g~about 4000m 2 / g. The activated carbon surface area is at least about 500 m2 / g, at least about 750m 2 / g, or at least about 1000m 2 In certain embodiments, the activated carbon surface area can be about 1000 m / g. 2 / g~about 3000m 2 / g. Typically, the surface area of ​​the activated carbon will be greater than the biocatalyst surface area because the surface area usually increases during activation (in the third heating vessel or heating zone). However, in certain embodiments, the activated carbon surface area is about the same as or lower than the biocatalyst surface area.

[0180] In preferred embodiments, the process is a water positive process characterized by a net water production of greater than 0 kg H2O per kg H2. In some embodiments, the net water production is at least 3 kg H2O per kg H2. In certain embodiments, the net water production is at least 6 kg H2O per kg H2.

[0181] In preferred embodiments of water-positive processes, no water is added to the process. Rather, the process utilizes water that enters with the biomass and, optionally, water produced in chemical reactions during the pyrolysis of the biomass. For example, a water-positive process does not require the addition of tap water or fresh water such as seawater, lake water, or river water. Water that enters with the biomass feedstock is incorporated into the biomass through natural and renewable processes (e.g., absorption of rainwater directly into the biomass or through the soil, adsorption of moisture from the atmosphere, etc.).

[0182] The disclosed process can produce significantly more net water than electrolysis, which consumes a stoichiometrically large amount of water. The disclosed process can also produce significantly more net water than steam reforming of natural gas, which typically contains less than 100 ppm H2O. Therefore, methane steam reforming requires a large amount of water reactant source, making it a water-intensive process. From a water balance perspective, the present technology is fundamentally superior to conventional H2 generation.

[0183] Carbon (in solid carbon or gaseous carbon such as CO, CO2 or CH4) 14 C / 12 Measurement of C isotope ratios is a proven technique. Similar concepts can be applied to hydrogen, 2 H / 1 Measure the H isotope ratio ( 2 (H is also called deuterium D). Fossil resources tend to be depleted in deuterium compared to biomass. See Schiegl et al., "Deuterium content of organic matter," Earth and Planetary Science Letters, Volume 7, Issue 4, 1970, Pages 307-313, and Hayes, "Fractionation of the Isotopes of Carbon and Hydrogen in Biosynthetic Processes," Mineralogical Society of America, National Meeting of the Geological Society of America, Boston, MA, 2001, which are incorporated herein by reference.

[0184] In particular, the natural deuterium content of organically bound hydrogen shows systematic variation depending on the origin of the sample. The hydrogen of both marine and terrestrial plants contains a few percent less deuterium than the water from which the plants grew. Coal and petroleum are more depleted in deuterium than plants, and natural gas is still more depleted in deuterium than the coal or petroleum from which it is derived. In this disclosure, "renewable hydrogen" does not consider the renewable potential of the hydrogen contained in the water (H2O) reactant used to react with carbon or CO2 to produce H2; in other words, only the hydrogen derived from the carbonaceous feedstock, and not the hydrogen derived from the water itself. 2 H / 1 It is determined by the correlation between the H isotope ratio and the reproducibility of the starting material. On average, water contains about 1 deuterium atom ( 1The ratio of deuterium atoms to hydrogen atoms in renewable biomass is slightly lower than 1 / 6,400, and the ratio of deuterium atoms to hydrogen atoms in non-renewable fossil resources (such as mined coal or mined natural gas) is even lower than that of renewable biomass. 2 H / 1 The H isotope ratio correlates with the renewable potential of hydrogen, 2 H / 1 A higher H isotope ratio indicates a higher renewable hydrogen content. 2 H / 1 The H isotope ratio can be about 0.0002 to about 0.001, for example, about 0.0002 to about 0.005. 2 H / 1 The H isotope ratio is higher than in an otherwise equivalent reducing gas composition derived from a fossil source rather than biomass. In some embodiments, the amount of hydrogen contained in the reducing gas composition is 2 H / 1 The H isotope ratio is in the range of about 1% to about 100%, or any number therebetween, for example, in the range of about 1%, 5%, 10%, 25%, 50%, or 100% higher, or any number therebetween.

[0185] In some embodiments of the present disclosure, the hydrogen product is characterized by at least 50% renewable hydrogen by hydrogen isotope analysis. In various embodiments, the hydrogen product is characterized by at least 80%, at least 90%, at least 95%, or at least 99% renewable hydrogen. In certain embodiments, the hydrogen product is characterized entirely by renewable hydrogen.

[0186] In some hydrogen products, the hydrogen is characterized as being entirely renewable hydrogen, and the residual carbon contained in the hydrogen product is 14 C / 12 It is essentially fully renewable carbon as determined by measurements of the C isotope ratio.

[0187] Renewable hydrogen can be recognized in the marketplace in a variety of ways, including renewable energy standards, renewable energy credits, and renewable energy identification numbers. As just one example, an oil refinery that uses renewable hydrogen to produce gasoline can receive renewable energy credits for such H2 content. In metal products such as steel, renewable hydrogen can be used in the metal production process (e.g., reduction of metal ores with H2), or renewable hydrogen can be used as a measurable alloying element in the final product.

[0188] In some processes, a portion of the reducing gas is combusted in a power generation unit to generate electricity, which is used in the process. Optionally, a portion of the electricity can be sold to a local power grid. The portion of the reducing gas combusted in the power generation unit can be a diverted portion (in a third heating vessel or heating zone) of the reducing gas produced in step (c) of the process. Alternatively, the reducing gas can be separated to form an H-rich stream and a CO-rich stream, with some or all of the CO-rich stream being fed to the power generation unit. In such embodiments, the process (and the location in which the process is performed) produces a carbon-negative and water-positive H product, an activated carbon product, and electricity with low carbon intensity.

[0189] In some embodiments, the process is continuous or semi-continuous, while in other embodiments, the process is a batch process.

[0190] Variations of the present disclosure can be understood with reference to the accompanying drawings (FIGS. 1, 2, 3 and 4), which illustrate various embodiments, but not by way of limitation.

[0191] 1 is a simplified block flow diagram of a process for converting biomass feedstock to carbon-negative hydrogen and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units.

[0192] 2 is a simplified block flow diagram of a process for converting biomass feedstock into a carbon-negative reducing gas and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units.

[0193] 3 is a simplified block flow diagram of a process for converting biomass feedstock to carbon-negative CO and optionally activated carbon, according to some embodiments. Dotted lines indicate optional streams and units.

[0194] 4 is a simplified block flow diagram of a process for converting biomass feedstocks to carbon-negative hydrogen using biocatalytic conversion and water-gas shift, according to some embodiments. Dotted lines indicate optional streams and units.

[0195] 1-4, some optional flows are not explicitly shown. For example, in the second heating vessel or heating zone, a substantially inert gas (e.g., N2) can be introduced at the bottom of the vessel or at one or more other feed locations above the second heating vessel or heating zone.

[0196] In the simplified block flow diagrams of Figures 1-4, the first, second, and third heating vessels or zones are shown as vertical, solids-downflow vessels. While this is the preferred embodiment, it is not meant to be the only way the vessels can be configured. The vessels can be horizontal rather than vertical. The vessels can be solids-upflow rather than solids-downflow. The vessels can be well mixed, for example, in a fluidized bed reactor.

[0197] In some embodiments, the dried biomass from the first heating vessel or heating zone is pelletized, and the dried biomass pellets are fed to a second heating vessel or heating zone. In some embodiments, the biocatalyst from the second heating vessel or heating zone is pelletized, or remains as pellets if the dried biomass pellets were fed, and the biocatalyst pellets are fed to a third heating vessel or heating zone. In some embodiments, the activated carbon from the third heating vessel or heating zone is pelletized, or remains as pellets if the biocatalyst pellets were fed, and the activated carbon pellets are recovered from the third heating vessel or heating zone. In this disclosure, references to pelleting conditions and pellet characteristics can refer to dried biomass pellets, biocatalyst pellets, or activated carbon pellets.

[0198] Pelletization can involve the use of a pellet binder. The binder can fill pores within the carbon material of the biocarbon pellets. Alternatively or additionally, the binder can be disposed on the surface of the pellets.

[0199] Optionally, pelleting can be performed without the introduction of an external binder. For example, the biocatalyst pellets can use an internal binder in the form of lignin or pyrolysis tar to bind the carbon matrix together to produce biocatalyst pellets that are fed into a third heating vessel or heating zone (and optionally removed as a by-product).

[0200] In some pellets that use a binder, the pellets include at least about 2 wt% to at most about 25 wt% of the binder, at least about 5 wt% to at most about 20 wt% of the binder, or at least about 1 wt% to at most about 5 wt% of the binder. In various embodiments, the pellets include about, at least about, or at most about 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, or 30 wt% of the binder, including all intermediate ranges.

[0201] The binder can be an organic binder or an inorganic binder. In some embodiments, the binder is or includes a renewable material. In some embodiments, the binder is or includes a biodegradable material. In some embodiments, the binder can be partially oxidized (e.g., via biocatalytic conversion) or combusted (e.g., after using the product).

[0202] The binder may be selected from starch, thermoplastic starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal powder, molten coke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, Gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, xanthan gum, polyvidone, polyacrylamide, polylactic acid, phenol formaldehyde resin, vegetable resin, recycled roofing materials, recycled tires, derivatives thereof, or combinations of the foregoing. In certain embodiments, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch-based polymers (e.g., polymers based on amylose and amylopectin), derivatives thereof, or combinations thereof. The starch can be a non-ionic starch, anionic starch, cationic starch, or zwitterionic starch.

[0203] The size and geometric shape of the pellets can vary. As used herein, "pellets" refers to agglomerated bodies, not loose powder. The geometric shape of pellets is not limited to spherical or nearly spherical. Also, in this disclosure, "pellets" is synonymous with "briquettes." The geometric shape of pellets can be spherical (round or ball-shaped), cylindrical, cubic (square), octagonal, hexagonal, honeycomb / honeycomb, elliptical, oval, pillar-shaped, rod-shaped, pillow-shaped, random, or a combination thereof. For convenience of disclosure, the term "pellets" is generally used to refer to any body containing powder agglomerated with a binder.

[0204] Pellets are characterized by an average pellet diameter, which is the actual diameter for spheres or cylinders and the equivalent diameter for any other 3D geometry. The equivalent diameter of a non-spherical pellet is the diameter of a sphere having a volume equivalent to the actual pellet. In some embodiments, the average pellet diameter is about or at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, or 25 millimeters, including all intermediate ranges. In some embodiments, the average pellet diameter is about or at least about 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, or 7500 microns, including all intermediate ranges.

[0205] The Hardgrove Grindability Index ("HGI") is a measure of the grindability of a material such as biomass or coal. The Hardgrove Grindability Index of a pellet can be at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. In some embodiments, the Hardgrove Grindability Index is at least about 30 and up to about 50, or at least about 50 and up to about 70. ASTM Standard D 409 / D 409M for "Standard Test Method for Grindability of Coal by Hardgrove Mechanical Method" is incorporated herein by reference in its entirety. Unless otherwise specified, all references to the Hardgrove Grindability Index or HGI in this disclosure refer to ASTM Standard D 409 / D 409M.

[0206] In various embodiments, the Hard Glove Crushability Index is about, at least about, or at most about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 13 9, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, including all intermediate ranges (e.g., 25-40, 30-60, etc.). In some embodiments, the Hard Glove Crushability Index is at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. For example, the Hard Glove Crushability Index can be at least about 30 and up to about 50, or at least about 50 and up to about 70.

[0207] The pellets are characterized by a pellet durability index of at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%. The pellets are characterized by a pellet durability index of less than 99%, less than 95%, less than 90%, less than 85%, or less than 80%. Unless otherwise noted, all references to pellet durability index in this disclosure refer to ISO 17831-1:2015 "Solid biofuels - Determination of mechanical durability of pellets and briquettes - Part 1: Pellets," which is incorporated herein by reference in its entirety.

[0208] In some embodiments, the pellets are crushed to produce smaller pellets. The crushing step, and in some embodiments the screening step, can be integrated with another process, including potentially integrating at the site of the industrial application. The optional step of producing smaller pellets can utilize crushing equipment selected from a hammer mill, attrition mill, disc mill, pin mill, ball mill, cone crusher, jaw crusher, rock crusher, or combinations thereof.

[0209] Some variations provide a process for producing carbon negative hydrogen and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating under effective biocatalytic conversion conditions and water-gas shift conditions, thereby producing H and CO; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H2 from the third heated vessel or heated zone, wherein the H2 is carbon-negative hydrogen characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0210] In some embodiments, a first portion of the biogas is fed to a third heating vessel or heating zone. In other embodiments, no biogas is fed to the third heating vessel or heating zone. When some biogas is fed to the third heating vessel or heating zone, effective biocatalytic conversion conditions in step (c) can result in biocatalytic conversion of the biogas, where the biocatalytic conversion of the biogas is catalyzed by a biocatalyst. There can also be non-catalytic / homogeneous biocatalytic conversion of the biogas, or biocatalytic conversion catalyzed by ash or metals present in the reactor walls or stream.

[0211] In some embodiments, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of the biocatalyst itself. In certain embodiments in which a portion of the biogas is fed to a third heating vessel or heating zone, the effective biocatalytic conversion conditions in step (c) result in biocatalytic conversion of the biogas as well as biocatalytic conversion of the biocatalyst. The biocatalytic conversion of the biogas can be catalyzed by the biocatalyst prior to conversion to a reducing gas.

[0212] In some embodiments, the process further comprises recovering a portion of the biocatalyst from step (b) as a biogenic carbon by-product.

[0213] In some embodiments, the process further includes separating a second recovered water stream from the biogas (e.g., using a condenser). The second recovered water stream can be supplied to a third heating vessel or heating zone to perform biocatalytic conversion of the biocatalyst. The second recovered water stream can be supplied to a third heating vessel or heating zone to perform water-gas shift of CO to produce additional H. In certain embodiments in which a first portion of the biogas is supplied to a third heating vessel or heating zone, the second recovered water stream can be supplied to a third heating vessel or heating zone to perform biocatalytic conversion of the biogas.

[0214] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are one common physical unit that is reused in steps (a), (b), and (c).

[0215] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are arranged sequentially in a continuous process.

[0216] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone operate countercurrently to the solid and gas phases, respectively.

[0217] In some embodiments, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each vertical, solids, downflow vessels.

[0218] In some embodiments, the first heating vessel or heating zone contains a substantially inert gas. Additionally or alternatively, the second heating vessel or heating zone can contain a substantially inert gas. In certain embodiments, the second heating vessel or heating zone contains less than 0.1 vol% oxygen.

[0219] The first heating vessel or heating zone operates at a drying temperature, for example, from about 100°C to about 400°C. The second heating vessel or heating zone operates at a pyrolysis temperature, for example, from about 300°C to about 900°C. The third heating vessel or heating zone operates at a biocatalytic conversion temperature, for example, from about 600°C to about 1200°C.

[0220] In some embodiments, the first portion of the biogas is fed to a third heating vessel or heating zone, and step (c) achieves a conversion of the biogas to reducing gas of at least 50% or at least 90%, where the conversion is calculated based on the biogas entering the third heating vessel or heating zone.

[0221] In some embodiments, step (c) achieves at least 25% or at least 50% conversion of biocatalyst to reducing gas, where this conversion is calculated based on the biocatalyst entering the third heated vessel or heated zone.

[0222] In some embodiments, at least a portion of the CO is recycled within the process. CO recycling can enhance the extent of the water-gas shift reaction, thereby making it available, for example, to produce additional H from CO and HO.

[0223] In some embodiments, CO2 is produced in step (c), and at least a portion of the CO2 is recycled within the process. CO2 recycling can be performed to reduce the reactivity of the environment in the previous step, such as in a first heating vessel or heating zone. CO2 recycling can be performed to increase the steam velocity in the previous step. CO2 recycling can be used to improve the extent of the dry reforming reaction, thereby producing additional H2 from CO2 and hydrocarbons (e.g., pyrolysis oil). In certain embodiments, CO2 drives the dry reforming of biogas or biocatalysts to produce additional reducing gas.

[0224] In some embodiments, the carbon intensity of carbon-negative hydrogen is less than -3,000 kg COe per metric ton of H. In particular embodiments, the carbon intensity of carbon-negative hydrogen is less than -10,000 kg COe per metric ton of H.

[0225] In some embodiments, the process is a water-positive process characterized by a net water production of greater than 0 kg HO per kg H. The net water production can be, for example, at least 3 kg HO per kg H, or at least 6 kg HO per kg H. In preferred embodiments of a water-positive process, no water is added to the process. Rather, the process utilizes water that enters with the biomass and water produced in chemical reactions during pyrolysis of the biomass.

[0226] In some embodiments, the process further includes supplying the metal oxide and H or CO to a fourth heating vessel or heating zone operating under effective metal oxide reducing conditions to reduce the metal oxide to pure metal or less reduced metal oxide. Optionally, a biocatalyst can also be supplied to the fourth heating vessel or heating zone, where the biocatalyst reacts with the metal oxide to form pure metal or less reduced metal oxide. In certain embodiments, the biocatalyst, rather than a reducing gas, is supplied to the fourth heating vessel or heating zone. As used herein, "less reduced metal oxide" refers to a metal oxide product that is partially reduced compared to the starting metal oxide reactant, but not as reduced as a zero-valent metal.

[0227] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are arranged sequentially in a continuous process.

[0228] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone operate in countercurrent flow with respect to the solid and gas phases.

[0229] In some embodiments using a fourth heating vessel or heating zone, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are each vertical, solids, downflow vessels.

[0230] In some embodiments, the dried biomass is pelleted prior to step (b). Alternatively or additionally, the biocatalyst can be pelleted prior to step (c).

[0231] In some embodiments, the biocatalyst is a 14 C / 12 In a preferred embodiment, the biocatalyst is at least 90% reproducible as determined from measurements of the C isotope ratio. 14 C / 12 It is fully reproducible as determined from measurements of C isotope ratios.

[0232] In some embodiments, the biocatalyst contains at least about 50 wt% fixed carbon. In certain embodiments, the biocatalyst contains at least about 80 wt% fixed carbon.

[0233] In some embodiments, the biocatalyst is about 200 ml 2 / g~about 2000m 2 / g. The biocatalyst surface area is at least about 400 m 2 / g, at least about 800m 2 / g, or at least about 1200 m 2 In certain embodiments, the biocatalyst surface area can be about 500 m / g. 2 / g~about 1500m 2 / g.

[0234] In some embodiments, a portion of the reducing gas is combusted in a power generation unit to generate electricity, which can be used within the process or exported as an electrical by-product.

[0235] In some embodiments where carbon-negative hydrogen is produced and activated carbon is not necessarily recovered, the process is a water-positive process characterized by a net water production of greater than 0 kg HO per kg of H. In certain embodiments, the net water production is at least 3 kg HO per kg of H. In preferred embodiments, the net water production is at least 6 kg HO per kg of H.

[0236] In some variations, the carbon negative hydrogen product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing H, CO, and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H and activated carbon from the third heated vessel or heated zone, wherein the H is a carbon-negative hydrogen product characterized by a carbon intensity of less than 0 kg COe per metric ton of H.

[0237] In some embodiments of the carbon-negative hydrogen product, the process for producing the carbon-negative hydrogen product is a water-positive process characterized by a net water production of greater than 0 kg HO per kg of H. In certain embodiments, the net water production is at least 3 kg HO per kg of H. In preferred embodiments, the net water production is at least 6 kg HO per kg of H.

[0238] Another variation provides a process for producing a carbon negative reducing gas and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing a reduced gas and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering the reducing gas and activated carbon from the third heated vessel or heated zone, wherein the reducing gas is a carbon negative reducing gas characterized by a carbon intensity of less than 0 kg COe per metric ton of said reducing gas.

[0239] Another variation provides a process for producing carbon negative CO and activated carbon, the process comprising: (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing CO, H, and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering CO and activated carbon from the third heated vessel or heated zone, wherein the CO is carbon negative carbon monoxide characterized by a carbon intensity of less than 0 kg CO2e per metric ton of CO.

[0240] In some variations, the activated carbon product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing H, CO, and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; and (f) recovering the activated carbon product from the third heating vessel or heating zone.

[0241] In some variations, the carbon negative hydrogen product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating under effective biocatalytic conversion conditions and water-gas shift conditions, thereby producing H and CO; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering H from the third heated vessel or heated zone, wherein the H is a carbon-negative hydrogen product characterized by a carbon intensity of less than 0 kg COe per metric ton of H.

[0242] In some embodiments of the carbon-negative hydrogen product, the process for producing the carbon-negative hydrogen product does not necessarily recover activated carbon and is a water-positive process characterized by a net water production of greater than 0 kg HO per kg of H. In certain embodiments, the net water production is at least 3 kg HO per kg of H. In preferred embodiments, the net water production is at least 6 kg HO per kg of H.

[0243] In some variations, the carbon negative reduced gas product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing a reduced gas and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering the reducing gas and activated carbon from the third heated vessel or heated zone, wherein the reducing gas is a carbon-negative reducing gas product characterized by a carbon intensity of less than 0 kg COe per metric ton of reducing gas.

[0244] In some variations, the carbon negative CO product is (a) feeding biomass into a first heating vessel or heating zone operating at effective drying conditions to remove moisture from the biomass, thereby producing a dried biomass and a first recovered water stream; (b) feeding the dried biomass into a second heating vessel or heating zone operating at effective pyrolysis conditions to pyrolyze the dried biomass, thereby producing a biocatalyst and a biogas; (c) feeding the biocatalyst, the first recovered water stream, and optionally a first portion of the biogas to a third heating vessel or heating zone operating at effective biocatalytic conversion conditions, thereby producing CO, H, and activated carbon; (d) thermally oxidizing a second portion of the biogas to produce process heat; (e) using the process heat from step (d) to heat a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone; (f) recovering CO and activated carbon from the third heated vessel or heated zone, wherein the CO is a carbon-negative CO product characterized by a carbon intensity of less than 0 kg COe per metric ton of CO.

[0245] Another variation of the present invention provides a system for producing carbon-negative hydrogen, the system comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and a biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; a third heating vessel or heating zone configured to (i) receive a biocatalyst, (ii) optionally receive a first portion of the biogas, and (iii) produce H and CO, the third heating vessel or heating zone being in fluid communication with the second heating vessel or heating zone and comprising means for recovering H; a thermal oxidizer configured to oxidize at least a portion of the biogas to generate heat, the thermal oxidizer in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated and capable of producing carbon-negative hydrogen, characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0246] In some systems, a third heating vessel or heating zone is configured to receive the first portion of the biogas and convert a portion of the biogas to H2 and CO.

[0247] The system may further comprise a separation unit configured to separate the second recovered water stream from the biogas. The third heating vessel or heating zone may comprise an inlet for receiving the second recovered water stream.

[0248] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are spatially arranged sequentially such that operation of the system is sequential.

[0249] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate countercurrently with respect to the solid and gas phases, respectively.

[0250] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical, solids, downflow vessel.

[0251] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone each comprise an internal vessel lining.

[0252] The system may further include a fourth heating vessel or heating zone configured to reduce the metal oxide to pure metal or a less reduced metal oxide using H or CO. Alternatively or additionally, the fourth heating vessel or heating zone may be configured to reduce the metal oxide to pure metal or a less reduced metal oxide using a biocatalyst. In such a system, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone may be spatially arranged sequentially to enable operation of the system to operate sequentially.

[0253] The system can further include a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

[0254] The system may further include a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

[0255] In some systems, a power generation unit is configured to combust a portion of the biogas to generate electricity, and the power generation unit can be configured to power components in the system that require a power source.

[0256] Yet another variation provides a system for producing carbon negative hydrogen and activated carbon, the system comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and a biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; a third heating vessel or heating zone configured to (i) receive a biocatalyst, (ii) optionally receive a first portion of the biogas, and (iii) produce H, CO, and activated carbon, the third heating vessel or heating zone in fluid communication with the second heating vessel or heating zone, the third heating vessel or heating zone comprising a means for recovering H, and comprising a means for recovering the activated carbon; a thermal oxidizer configured to oxidize a second portion of the biogas to generate heat, the thermal oxidizer in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated and capable of producing carbon-negative hydrogen, characterized by a carbon intensity of less than 0 kg CO2e per metric ton of H2.

[0257] In some systems for producing both hydrogen and activated carbon, a third heating vessel or heating zone is configured to receive a first portion of the biogas and convert a portion of the biogas to H and CO.

[0258] In some systems for producing both hydrogen and activated carbon, the system can further include a separation unit configured to separate the second recovered water stream from the biogas. The third heating vessel or heating zone can be configured with an inlet for receiving the second recovered water stream.

[0259] In some systems for producing both hydrogen and activated carbon, a first heating vessel or heating zone, a second heating vessel or heating zone, and a third heating vessel or heating zone are spatially arranged sequentially to allow operation of the system to operate sequentially.

[0260] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate countercurrently to the solid and gas phases, respectively.

[0261] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical, solids, downflow vessel.

[0262] In some systems for producing both hydrogen and activated carbon, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone each comprise an internal vessel lining.

[0263] In some systems for producing both hydrogen and activated carbon, the system can further include a fourth heating vessel or heating zone configured to reduce metal oxides to pure metals or less reduced metal oxides using H or CO. Alternatively, or additionally, the fourth heating vessel or heating zone can be configured to reduce metal oxides to pure metals or less reduced metal oxides using a biocatalyst. In such systems, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone can be spatially arranged sequentially to enable operation of the system to operate sequentially.

[0264] In some systems for producing both hydrogen and activated carbon, the system may further include a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

[0265] In some systems for producing both hydrogen and activated carbon, the system may further include a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

[0266] In some systems for producing both hydrogen and activated carbon, a power generation unit is configured to combust a portion of the biogas to generate electricity, which can be configured to power components in the system that require a power source.

[0267] The separation unit configured to separate the second recovered water stream from the biogas can be, for example, a single-stage condenser, a multi-stage condenser, an adsorption unit, or a centrifuge. In certain embodiments, the second recovered water stream is the output of a final stage condenser of a multi-stage condenser.

[0268] In some systems, the third heating vessel or heating zone is configured with an inlet for receiving a second recovered water stream derived from biogas. The second recovered water stream can be combined with the first recovered water stream and the combined water can be fed to the third heating vessel or heating zone. Alternatively, different inlet ports can be provided for the first and second recovered water streams. Typically, the second recovered water stream is much smaller than the first recovered water stream unless the biomass is relatively dry. For example, the second recovered water stream (if applicable) can be about 1% to about 25%, e.g., about 2% to about 10%, by weight of the mass of the first recovered water stream.

[0269] In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are spatially sequentially arranged to allow continuous operation of the system. The first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone can each be a countercurrent vessel for the solid and gas phases. The first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone can each be a vertical, solid downflow vessel. The first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone can each be configured with an internal vessel lining using the lining materials described above.

[0270] In some systems, the system further comprises a fourth heating vessel or heating zone configured to reduce metal oxides to pure metals or less reduced metal oxides using H or CO. Alternatively or additionally, the system may further comprise a fourth heating vessel or heating zone configured to reduce metal oxides to pure metals or less reduced metal oxides using a biocatalyst. In some systems, the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are spatially sequentially arranged to allow continuous operation of the system. The first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone may operate in countercurrent flow with respect to the solid and gas phases. The first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone may each be a vertical, solid downflow vessel. The first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone and the fourth heating vessel or heating zone may each be configured with an internal vessel lining.

[0271] The hydrogen produced by the disclosed process can be used for a variety of industrial applications including hydrogen vehicles, power production, fertilizer production through ammonia synthesis, metal alloying, glass production, electronics processing such as evaporation, cleaning, etching and reduction, production of methanol or methanal derivatives such as dimethyl ether, acetic acid, ethylene, propylene or formaldehyde, Fischer-Tropsch synthesis, crude oil refining, hydrogenation of olefins or aromatic hydrocarbons, production of rocket fuel, use in energy conversion devices such as hydrogen fuel cells, solid oxide fuel cells, Stirling engines, microturbines, internal combustion engines, thermoelectric generators, scroll expanders, gas burners or thermophotovoltaic devices, and many other applications.

[0272] For example, direct reduction of iron ore using hydrogen could be developed into an important industrial process in steel production. Conventional blast furnaces emit large amounts of carbon dioxide. By replacing carbon or carbon monoxide with hydrogen to reduce metal oxides to metal products, the by-product shifts toward water rather than carbon dioxide. The hydrogen used in iron ore reduction is renewable, and the environmental benefits to metal products are enormous when the carbon intensity is low and the net water content is positive. Therefore, hydrogen provided by this technology is highly useful for reducing metal oxides of a wide variety of metals to metal products, including, but not limited to, iron, copper, nickel, magnesium, manganese, aluminum, tin, zinc, cobalt, chromium, tungsten, molybdenum, titanium, gold, silver, lead, silicon, lithium, boron, zirconium, vanadium, platinum, palladium, rhodium, gallium, germanium, indium, bismuth, or combinations or alloys thereof. An exemplary alloy is an iron-chromium-nickel-molybdenum alloy, such as 316 stainless steel.

[0273] Metals are an important group of products that can be produced using the disclosed forms of carbon, hydrogen, or both. Most metals occur naturally in rocks in the Earth's crust in the form of metal ores. Metal ores are generally metal oxides, metal sulfides, or metal silicates. Metal ores must be processed to produce the desired metal from the ore mineral. Processing metal ores to pure metals can utilize carbon or hydrogen as reactants in various reduction reactions that produce the metal plus reaction products. While the conversion of iron ore to iron is a traditionally common example, many metal ores can be processed using carbon or hydrogen at some point in the production of metals. If a metal ore contains metal sulfides, the metal sulfides can be converted to metal oxides before reacting with carbon.

[0274] In this disclosure, "carbon-negative metal products" can include any metals produced from metal-containing precursors using the disclosed carbon-negative carbon compositions, or carbon oxides derived therefrom. Carbon-negative metal products also include any metals produced from metal-containing precursors using the disclosed carbon-negative and water-positive reducing gases, which can be H or CO.

[0275] In certain variations, the carbon negative metal product is characterized by a carbon intensity of less than 0 kg CO2e per metric ton of carbon negative metal product, the carbon negative metal product containing about 50 wt% to about 99 wt% metal and about 1 wt% to about 50 wt% one or more alloying elements. In various embodiments of the carbon negative metal product, the carbon intensity is about -50, -100, -150, -200, -250, -300, -350, -400, -450, or -500 kg CO2e per metric ton of carbon negative metal product, or less, including any intermediate ranges.

[0276] In certain embodiments, the carbon-negative metal product is an iron product or a steel product. "Steel" refers to an alloy of iron with at least carbon and usually other elements, and is widely used as a structural material throughout the world. The production of iron and steel is discussed in more detail later in this specification.

[0277] In certain embodiments, the carbon-negative metal product is a nickel product. Nickel ore contains a large amount of nickel sulfide. Nickel sulfide can be reacted with carbon monoxide in the presence of a sulfur catalyst at temperatures between 40 and 80°C to produce nickel carbonyl, Ni(CO)4. Nickel is then obtained from nickel carbonyl by thermal decomposition of Ni(CO)4 to Ni and CO, which can be recycled for further reactions with the raw nickel sulfide. The initial CO can be produced from the disclosed carbon-negative carbon product.

[0278] In certain embodiments, the carbon-negative metal product is a cobalt product. Cobalt ore typically contains cobalt sulfide, which can be converted to cobalt sulfate by roasting. Cobalt oxide can be produced from cobalt sulfide and cobalt sulfate using, for example, reaction with sodium hypochlorite. The cobalt oxide (e.g., Co3O4) can then be reduced to cobalt metal (Co) by reduction with the disclosed carbon-negative carbon product in a blast furnace.

[0279] In certain embodiments, the carbon-negative metal product is a manganese product or a ferromanganese product. To produce manganese, manganese ore can be mixed with the disclosed carbon-negative carbon product and then reduced in either a blast furnace or an electric arc furnace. To produce ferromanganese, manganese ore can be mixed with iron ore and the disclosed carbon-negative carbon product and then reduced in either a blast furnace or an electric arc furnace. The resulting ferromanganese has a manganese content of 30 wt% to 80 wt%.

[0280] In certain embodiments, the carbon-negative metal product is an aluminum product. Traditionally, aluminum cannot be extracted from ore (typically Al2O3-rich bauxite) by carbon reduction because it is too high in the electrochemical series and the temperatures required for the endothermic reaction are too high. As a result, high energy requirements result in high carbon strength. However, the present disclosure enables the production of carbon-negative aluminum products by reducing aluminum oxide with the disclosed carbon-negative carbon products, utilizing the energy generated in conjunction with the disclosed carbon-negative carbon products (e.g., combustion of pyrolysis steam). That is, while the inherent energy requirements are primarily dictated by reaction kinetics and thermodynamics, both the energy required to convert aluminum ore and the carbon used have low or negative carbon strengths consistent with aluminum production.

[0281] In certain embodiments, the carbon-negative metal product is a platinum product. Platinum ore typically contains platinum sulfide, which can react with the disclosed carbon-negative carbon products or carbon monoxide derived therefrom to form platinum metal (Pt) and carbonyl sulfide (COS) or other sulfide products.

[0282] In certain embodiments, the carbon-negative metal product is a silicon product. In this disclosure, silicon is considered a metal. Metallurgical-grade silicon is typically produced in an electric arc furnace using graphite electrodes. Hot gas is generated in the bottom region of the reactor while silicon is formed under the intense energy and temperature input from the electric arc. Similar to producing Al from Al2O3, producing Si from SiO2 requires consideration of reaction kinetics and thermodynamics. Carbon-negative silicon (Si) products can be produced by achieving the overall chemical reaction SiO2 + C → Si + CO2 using the disclosed carbon-negative carbon products. The energy required for the chemical reaction can be obtained from processes related to the disclosed carbon-negative carbon products (e.g., combustion of pyrolysis steam), further reducing the carbon intensity of the silicon product.

[0283] In certain embodiments, the carbon-negative metal product is a lithium product. Lithium ore can contain lithium oxide. The lithium oxide can then be reduced to lithium (Li) by reduction with the disclosed carbon-negative carbon product in a high-temperature reactor or furnace. Some ores (e.g., spodumene and petalite) contain Li2O, Al2O3, and SiO2 and can be processed to produce metal alloys containing Li, Al, and Si, or single metal products (Li, Al, or Si). Lithium ore can also contain lithium silicate. The lithium silicate can react with the disclosed carbon-negative carbon product to form lithium metal.

[0284] The production of silicon and lithium, as described in the previous two paragraphs, is particularly important in today's economy. Silicon is a key material for computers and many electronic devices, and lithium is a key material for batteries (e.g., lithium-ion batteries). Both silicon and lithium are in short supply. Furthermore, many applications of silicon and lithium, such as in electric vehicles, are being promoted as low-carbon-intensity alternatives to traditional fossil fuels. Therefore, carbon-negative silicon and carbon-negative lithium are believed to be particularly commercially attractive.

[0285] In addition to relatively pure metal or metal alloy products, carbon-negative carbon-metal composites can also be produced. Carbon-metal composites contain at least 1 wt% carbon, typically at least 5 wt% carbon, or at least 10 wt% carbon. Carbon-metal composites can contain more carbon than metal, for example, more than 50 wt% carbon, up to about 95 wt% carbon. Carbon-metal composites have a variety of uses. Carbon-metal composites can be manufactured into pellets or powders as intermediate products that can be shipped elsewhere for final conversion to metal. Carbon-metal composites also find application as battery electrodes. For example, in some electrodes, metal is combined with graphite or another form of carbon to form the electrode. One example is a carbon-lithium composite used in an anode. Lithium ore can react with the disclosed carbon-negative carbon product to form a lithium-carbon composite product, with some of the added carbon remaining while another portion of the carbon reduces lithium oxide or sulfide to lithium metal.

[0286] In addition to relatively pure metals, metal alloys, or carbon-metal composites, carbon-negative metal carbides can be produced. Examples include silicon carbide (SiC), titanium carbide (TiC), and tungsten carbide (WC). Because metal carbides have a stoichiometric amount of carbon in the compound, a large amount of carbon is effectively sequestered, thereby further reducing greenhouse gas emissions and, therefore, carbon intensity. In some embodiments, for example, in silicon production, the product contains metal (Si) as well as metal carbide (SiC). In some embodiments, metal carbides are reaction intermediates in metal production.

[0287] In some embodiments, carbon-negative metal hydrides can be produced, including carbon-negative and water-positive hydrogen provided by the present disclosure. Exemplary metal hydrides include magnesium hydride, manganese hydride, aluminum hydride, tungsten hydride, titanium hydride, silicon hydride, lithium hydride, zirconium hydride, and combinations thereof.

[0288] The reaction to convert metal ores to metals, metal alloys, carbon-metal composites, or metal carbides can be carried out in a blast furnace, a top gas recirculating blast furnace, a shaft furnace, a reverberatory furnace (also called an air furnace), a crucible furnace, a silencer furnace, a retort furnace, a flash furnace, a Tecnored furnace, an Ausmelt furnace, an ISASMELT furnace, a puddle furnace, a bogie furnace, a continuous chain furnace, a pusher furnace, a rotary furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, a direct reduction metal furnace, a smelter, or a combination or derivative thereof. Specific types of furnaces and reactors are described in more detail later in this specification.

[0289] In some embodiments, the carbon negative metal product contains between about 0.1 wt% and about 50 wt% of one or more alloying elements, for example, between about 1 wt% and about 10 wt% of one or more alloying elements. In various embodiments, the one or more alloying elements are individually or collectively present in the carbon negative metal product at a concentration of about, at least about, or at most about 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, or 20 wt%, including any intermediate ranges.

[0290] The one or more alloying elements can be selected from Al, Bi, B, C, Ce, Cr, Cu, Fe, H, Mg, Mn, Mo, N, Nb, Ni, P, Pb, Si, Sn, S, Ta, Ti, W, V, Zr, Zn, oxides, carbides, hydrides, nitrides, or sulfides of the foregoing elements, or combinations thereof. The carbon-negative metal product can include other elements, which may or may not function as alloying elements.

[0291] In some embodiments of the carbon-negative metal product, the alloying element comprises carbon. When carbon is present in the carbon-negative metal product, the carbon can be present at an equilibrium concentration within the one or more metals. Alternatively, the carbon can be present at a non-equilibrium concentration within the one or more metals, which can be lower or higher than the equilibrium concentration of carbon.

[0292] In some embodiments, the alloying element comprises carbon obtained from the carbon-negative carbon product disclosed herein. In various embodiments, the carbon-negative metal product comprises carbon at a concentration of about, at least about, or at most about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.5, 3, 3.5, 4, 4.5, or 5 wt %, including any intermediate range.

[0293] In some embodiments, the alloying element is carbon. 14 C / 12 The alloy carbon contains carbon that is at least partially renewable as determined from measurements of the C isotope ratio. 14 C / 12 It can be at least 50%, at least 90%, at least 95%, or 100% renewable as determined from C isotope ratio measurements.

[0294] In certain embodiments, the alloying element includes hydrogen, which can be carbon-negative and water-positive as disclosed herein. Hydrogen can tailor certain properties of the metal alloy. Metal hydrides have various applications in batteries (e.g., nickel-metal hydride batteries) and other electrochemical devices.

[0295] In certain embodiments, the alloying element includes nitrogen. High-strength austenitic stainless steels can benefit from nitrogen. Nitrogen has a higher solid solubility than carbon, is a strong austenite stabilizer, an excellent interstitial solid solution strengthener, and improves pitting corrosion resistance. When nitrogen is obtained from a carbon-negative metallurgical carbon product that is itself derived from biomass feedstock, it can be carbon-neutral or carbon-negative if nitrogen is added to the growing biomass from atmospheric N2 via the nitrogen cycle. On the other hand, when alloying nitrogen is ultimately obtained from NH3-based fertilizer, and NH3 is obtained from energy-intensive Haber synthesis, such nitrogen is generally not carbon-neutral or carbon-negative. The contribution to the overall carbon strength of the metal product can be very low, since the nitrogen content, if present, is typically less than 1 wt%. The Haber process can also be reduced in carbon intensity by, for example, using renewable energy to split water to produce H2 or by using renewable hydrogen as disclosed elsewhere in this patent application.

[0296] In certain embodiments, the alloying element includes oxygen. Oxygen is typically not a preferred alloying element, especially when metal oxides are to be avoided. However, certain alloys, particularly non-ferrous alloys, can use oxygen (as O atoms) as an interstitial alloying element to strengthen the metal through interstitial solid solution strengthening. It is recognized that oxygen can be obtained from atmospheric CO2 by photosynthesis when the oxygen is obtained from carbon-negative metallurgical carbon products obtained from biomass feedstocks.

[0297] In certain embodiments, the alloying element comprises sulfur. When the sulfur is obtained from a carbon-negative metallurgical carbon product obtained from a biomass feedstock, the carbon intensity of the sulfur depends on the source of the sulfur (e.g., soil and added fertilizer).

[0298] In certain embodiments, the alloying element includes phosphorus. When the phosphorus is obtained from a carbon-negative metallurgical carbon product obtained from a biomass feedstock, the carbon intensity of the phosphorus depends on the source of the phosphorus (e.g., soil and added fertilizer).

[0299] In various embodiments, the carbon negative metal product is in a form selected from a powder, pellet, sheet, rod, bar, wire, coil, pipe, plate, wall, tank, cast structure, engineered structure, electromagnet, permanent magnet, or combinations thereof. The carbon negative metal product can be a final structure or can be a feedstock for producing metal-containing structures via conventional subtractive manufacturing, additive manufacturing, or other techniques.

[0300] Disclosed herein are improved processes and systems for producing renewable hydrogen for metal ore reduction and many other industrial applications. Some embodiments are based on processes and systems for producing renewable reducing gas from biomass. The reducing gas can be utilized to reduce metal oxides and to generate renewable hydrogen, which has numerous commercial applications worldwide.

[0301] In some embodiments, the pyrolysis reactor (second heating vessel or heating zone) is fed with dry wood or another dry biomass source. The pyrolysis reactor is configured to produce carbon and pyrolysis off-gas (also called biogas) from the feedstock. If the biomass is very dry, the first heating vessel or heating zone (see Figures 1-4) can, in principle, be omitted, in which case the second recovered water stream can be recovered and fed to a third heating vessel or heating zone for biocatalytic conversion. Economically, biomass feedstocks are rarely completely dry due to the supply chain and logistics involved with biomass. Therefore, it is often preferable to include the first heating vessel or heating zone and recover some or most of the water in the biomass for use in the third heating vessel or heating zone.

[0302] The third heating vessel or heating zone can be a reactor configured to receive the carbon-recovery water and, optionally, another reactant, such as air or oxygen, to react to produce a reduced gas. The reduced gas can include hydrogen and carbon monoxide. Optionally, a water-gas shift reaction is used to convert HO to H (and CO to CO) to increase the hydrogen content of the reduced gas. The reduced gas can be sent to a separation unit to recover a hydrogen-rich product.

[0303] The fourth heating vessel or heating zone is a reactor or furnace configured to directly or indirectly receive (a) the reducing gas from the third heating vessel or heating zone, and (b) a reduction off-gas comprising metal oxides and at least HO operating under reducing conditions effective to convert the metal oxides to reduced metals, where the reduction off-gas may further comprise CO and CO. The process may be carried out at a metal oxide mine site, such as an iron ore mine, or at a metal oxide processing plant, such as a taconite processing plant. The process may reduce or eliminate pollution and costs associated with incineration, pelletizing, and transporting iron ore (or other metal oxides). The process may also reduce pollution and costs of coking coal to produce metallurgical coke or transporting petroleum coke to a blast furnace. The process may also improve the metal purity of the final metal product.

[0304] In some embodiments, step (b) is carried out at a pyrolysis temperature selected from about 250° C. to about 1250° C., e.g., from about 300° C. to about 700° C. In these or other embodiments, step (b) is carried out for a pyrolysis time selected from about 10 seconds to about 24 or 48 hours. Generally, lower pyrolysis temperatures require longer pyrolysis times, while higher pyrolysis temperatures allow for shorter pyrolysis times.

[0305] In some embodiments, step (c) is carried out at a reaction temperature selected from about 300°C to about 1200°C, e.g., about 400°C to about 1000°C. In these or other embodiments, step (c) is carried out for a reaction time selected from about 1 second to about 1 hour. Generally, the reaction temperature for forming the reducing gas is selected to achieve the desired chemical reaction. The reaction time can be dictated by the transfer of mass and heat to and from the reaction solids, and in some embodiments, smaller particles are converted in shorter reaction times.

[0306] In some embodiments employing a fourth heating vessel or heating zone, the reduction temperature in the fourth heating vessel or heating zone can be selected from about 500°C to about 2000°C, e.g., from about 700°C to about 1800°C. In these or other embodiments, the reduction time in the fourth heating vessel or heating zone can be selected from about 30 minutes to about 48 hours. Generally, lower reduction temperatures require longer reduction times, while higher reduction temperatures allow for shorter reduction times.

[0307] In some embodiments, the biomass is softwood chips, hardwood chips, wood logging residues, tree branches, tree stumps, leaves, bark, sawdust, corn, cornstalks, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugar beet, sugar beet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, fruit shells, fruit stems, fruit peels, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pumice, almond shells, pecan shells, coconut shells, coffee grounds, food waste, commercial waste, grass pellets, hay pellets, wood pellets, cardboard, paper, paper pulp, paper packaging, paper scraps, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof.

[0308] The biocatalyst produced in step (b) can comprise at least about 50 wt%, at least about 75 wt%, or at least about 90 wt% carbon (also referred to as total carbon). In various embodiments, the biocatalyst comprises at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 wt% carbon. Total carbon refers to fixed carbon present in volatile materials plus non-fixed carbon. In some embodiments, component weight percentages are absolute values ​​and are assumed to be absolute unless otherwise specified. In other embodiments, component weight percentages are exclusive of moisture and ash.

[0309] The biocatalyst produced in step (b) can comprise at least about 50 wt%, at least about 75 wt%, or at least about 90 wt% fixed carbon. In various embodiments, the biologically derived reagent comprises at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 wt% fixed carbon.

[0310] Metal processing is a very important industry worldwide. For example, according to "Steel Market Size, Share & Trends Analysis 2018-2025" by Grand View Research, Inc. (2017), the global steel market size for iron and steel alloys is expected to reach US$1 trillion by 2025. Increasing interest among builders in sustainable, low-cost, and durable building materials is driving demand for steel in industrial infrastructure and residential projects. In prefabricated metal buildings, which require high structural strength, steel plays a key role in providing stability, design flexibility, and aesthetics. Strict regulations promoting greener and more energy-efficient buildings are also driving increased demand for steel, especially in industrial structures.

[0311] Approximately 70% of steel is produced from pig iron, obtained by reducing iron oxide in a blast furnace with coke or coal, before reduction in an oxygen-blown converter. The use of non-renewable coal or coal-derived coke not only depletes fossil fuel resources but also releases non-renewable carbon dioxide into the atmosphere.

[0312] Iron oxide ore is mined all over the world. The iron ore goes through a beneficiation process where the iron is crushed and concentrated, then rolled into pellets (with a binder), heated in hardening furnaces that burn coal for heat, hardening the pellets, and sent to a blast furnace where coke is used to reduce the oxygenated ore to metallic iron. The hardening and coking processes produce large amounts of CO2 and other pollutants.

[0313] Metal processing produces net CO2 emissions worldwide each year. One of the biggest drawbacks of traditional blast furnaces is the unavoidable CO2 emissions when iron is reduced from iron oxide by carbon or carbon monoxide (CO). The steel industry is one of the largest CO2-emitting industries in the world today. There is a strong desire to make metal manufacturing processes more environmentally friendly.

[0314] In processes aimed at metal production, the conditions for step (b) can vary widely depending on the desired composition of the biocatalyst and biogas, the starting material, the type of metal oxide, the reactor configuration, and other factors (discussed in detail below). Generally, at higher pyrolysis temperatures, such as about 600°C to about 850°C, more hydrogen is produced in the biogas and less hydrogen remains in the biocatalyst. This is advantageous in embodiments where hydrogen in the biogas is utilized for metal oxide reduction. On the other hand, at lower pyrolysis temperatures, such as about 400°C to about 600°C, more hydrogen remains in the biocatalyst and therefore less hydrogen remains in the biogas. This can be advantageous in embodiments where hydrogen in the biocatalyst is utilized for metal oxide reduction, such as injecting biogenic carbon into a metal reduction reactor. In either scenario, hydrogen can be utilized for metal oxide reduction, which is desirable because it avoids direct CO2 generation, thereby improving the environmental footprint through reduced carbon intensity.

[0315] In some embodiments, the metal oxide to be converted is contained in a metal ore, such as iron ore, copper ore, nickel ore, magnesium ore, manganese ore, aluminum ore, tin ore, zinc ore, cobalt ore, chromium ore, tungsten ore, molybdenum ore, or a combination thereof. In certain embodiments, the metal ore is an iron ore, for example, an iron ore selected from hematite, magnetite, limonite, taconite, or a combination thereof. In some embodiments, the reduced form of the selected metal oxide is the fully reduced metal (e.g., fully reduced iron, Fe 0 ). In other embodiments, the reduced form of the selected metal oxide is a second metal oxide having a lower oxidation state than the selected metal oxide. For example, iron in FeO has an oxidation state of +2, while iron in Fe2O3 has an oxidation state of +3. The metal oxide can be contained in beneficiated metal ore, i.e., metal ore that has been processed in one or more beneficiation units. The metal oxide can be contained in metal ore in particulate, e.g., powder, form.

[0316] When a reducing gas is utilized to chemically reduce a selected metal oxide, CO, H, or both CO and H chemically reduce the metal oxide (e.g., FeO) to the corresponding metal (e.g., Fe) or a less reduced metal oxide (e.g., FeO is less reducing than FeO) in a chemical reaction with the metal oxide. The sensible heat contained in the oxidized biogas can be used to drive endothermic reactions thermodynamically, kinetically, or both. Skilled chemical engineers will appreciate that hot gas is useful for endothermic reactions requiring heat. Optionally, hot gas from biogas oxidation can be used to indirectly heat the reactor or to exchange heat with another gas before injecting it into the reactor. The temperature of the hot gas may be lower than the temperature of the reaction into which it is injected. In this case, the hot gas can actually be considered to be heated itself rather than providing heat. However, in this case, the reactor contents are not cooled as much as with the injection of a cold gas, and therefore endothermic chemistry still offers the advantage of relatively low overall energy usage compared to traditional approaches.

[0317] In certain embodiments, heat is generated by partial oxidation rather than complete oxidation (combustion) of biogas, intentionally producing additional reducing gases containing CO or H rather than combustion gases containing primarily CO and HO. The heat can be used to increase the temperature of pyrolysis or to heat other reactors. Although less heat is generated with partial oxidation compared to complete oxidation, more reducing gases are generated that are useful for producing hydrogen.

[0318] In some embodiments, the heavy hydrocarbons (e.g., aromatic tars) obtained in step (b) can be converted to reducing gases in a second heated vessel or zone or a third heated vessel or zone. The heavy hydrocarbons can be obtained from the biogas or from volatile carbon remaining on or in the biocatalyst.

[0319] In various embodiments, heat from the thermal oxidizer (FIGS. 1-4) is utilized for heating in step (a), heating in step (b), heating in step (c), heating elsewhere in the process, or a combination thereof. Optionally, a portion of the reducing gas is also oxidized, thereby generating heat. This heat can also be utilized for heating elsewhere in the process. In certain embodiments, the reducing gas containing H and CO is separated into H and CO, with H being recovered as the hydrogen product and CO being combusted to CO to provide heat for the process.

[0320] In some embodiments, the process further comprises separating hydrogen from the reducing gas and subsequently recovering the hydrogen. The hydrogen can be separated from the reducing gas via one or more separation techniques selected from, for example, pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation.

[0321] In some embodiments, in step (c), another reactant, in addition to water, is supplied to the third heated vessel or heated zone. The additional reactant can be selected from air, pure oxygen, enriched oxygen, ozone, or a combination thereof. Enriched oxygen refers to a gas composition containing O2 at a concentration of at least about 21 vol% together with N2 or other gases. In certain embodiments, the reactant in step (c) comprises a combination of water and oxygen.

[0322] The heating vessel can be, for example, a fixed bed reactor or a fluidized bed reactor. When a fixed bed reactor is used, the fixed bed can comprise or consist essentially of dried biomass (in the case of the first heating vessel or heating zone), formed biocatalyst (in the case of the second heating vessel or heating zone), formed activated carbon (in the case of the third heating vessel or heating zone), or formed metal (in the case of the optional fourth heating vessel or heating zone).

[0323] When a fluidized-bed reactor is used, the solid phase of the fluidized bed can be dried biomass (in the case of the first heating vessel or heating zone), biocatalyst (in the case of the second heating vessel or heating zone), activated carbon (in the case of the third heating vessel or heating zone), or metal (in the case of an optional fourth heating vessel or heating zone). Because fluidized-bed reactors are typically well mixed, the output is ideally the same as the contents inside; thus, for example, the solids in the second heating vessel or heating zone of a fluidized bed are the same as the output of biocatalyst sent to the third heating vessel or heating zone. If the flow pattern is closer to plug flow rather than well mixed, there is a conversion profile along the axial direction of a given reactor (e.g., dried biomass → biocatalyst in the second heating vessel or heating zone). In most practical devices (e.g., rotary kilns), the flow pattern lies between the extremes of plug flow and complete mixing.

[0324] There are various types of flow path connections between the first, second, third, and optionally fourth heating vessels or heating zones. In some embodiments, the outlet from one heating vessel is fitted with a screw conveyor located at or near the bottom of the vessel to continuously or periodically remove solids and transport them to the next heating vessel. In some embodiments, the heating vessels are stacked on top of each other, with gravity being used to transport solids from the top (feeding into the first heating vessel or heating zone) to the outlet of the third or fourth heating vessel or heating zone. Other solids transport means are known in the art.

[0325] Materials can generally be conveyed in and out of vessels by single screws, twin screws, rams, and the like. Materials can be mechanically conveyed by physical force (metal contact), pressure-driven flow, air-driven flow, centrifugal flow, gravity flow, fluidized flow, or other known means of moving solid and gas phases. In some embodiments, a fixed bed of pellets can be utilized.

[0326] As used herein, "reactor" or "vessel" can refer to a single reaction vessel or reaction zones contained within a reaction vessel. When a single reactor or vessel contains multiple reaction zones, the number of zones can be two, three, four, or more.

[0327] The first vessel and the second vessel can be physically contained within a single reactor such that the first vessel is a first zone and the second vessel is a second zone of the same physical equipment as the first zone. In these or other embodiments, the second vessel and the third vessel can be physically contained within a single reactor such that the second vessel is a first zone and the third vessel is a second zone of the same physical equipment as the first zone. In certain embodiments, the first vessel, the second vessel, and the third vessel are all physically contained within a single reactor such that the first vessel is a first zone, the second vessel is a second zone, and the third vessel is a third zone within a common physical equipment. If a fourth heated vessel or heated zone is used to produce the metal, the fourth vessel can be a fourth zone of the same physical equipment in which the previous zones are located.

[0328] It should also be noted that multiple physical devices can be used in a reactor in series or parallel. For example, the first reactor or vessel can be two physical reaction vessels operating in series (sequential), parallel, or a hybrid thereof. Similarly, the second vessel can be two physical reaction vessels operating in series (sequential), parallel, or a hybrid thereof. Multiple reaction vessels for the second vessel can be advantageous, for example, when it is desired to produce multiple different types of biocatalysts.

[0329] Similarly, the third vessel can be two physical reaction vessels operating in series (sequentially), parallel, or a hybrid thereof. Multiple reaction vessels for the third vessel can be advantageous, for example, when it is desired to produce multiple different types of activated carbon. For example, a main third reactor can be configured to produce a reducing gas and to continuously, periodically, or eventually remove activated carbon from the main third reactor, while, for example, a secondary third reactor can also be configured to produce a reducing gas but is not configured to remove activated carbon from the secondary third reactor.

[0330] In various embodiments, the hydrogen product is separated from the reducing gas via pressure swing adsorption, molecular sieve membrane separation, cryogenic distillation, or a combination thereof. Another means of separating hydrogen includes producing a product of hydrogen, such as magnesium hydride, and then releasing H.

[0331] The hydrogen product can comprise at least 50 mol% hydrogen. In some embodiments, the hydrogen product can comprise at least 90 mol% hydrogen. In various embodiments, the hydrogen product can comprise from about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100 mol% hydrogen, or any range therebetween.

[0332] In some hydrogen products, the hydrogen product contains up to about 1 mol% nitrogen, or is substantially free of nitrogen. In various embodiments, the hydrogen product contains from about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.04, 0.03, 0.02, or 0.01 mol% nitrogen, or any range therebetween. In this disclosure, a "substantially nitrogen-free" hydrogen product means that no nitrogen detectable by conventional analytical techniques is present in the product.

[0333] Some variations provide a reducing gas comprising hydrogen that is at least 50% renewable hydrogen according to hydrogen isotope analysis. In various embodiments, the reducing gas comprises hydrogen characterized by at least 80%, at least 90%, at least 95%, or at least 99% renewable hydrogen. In certain embodiments, the reducing gas comprises hydrogen characterized by entirely renewable hydrogen.

[0334] Regardless of whether the hydrogen is certified or characterized as renewable hydrogen, the compositional profile of the reducing gas can contain about or at least about 50 mol%, 60 mol%, 70 mol%, 80 mol%, 85 mol%, 90 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, 99 mol%, 99.5 mol%, or 99.9 mol% H. The remainder of the reducing gas can include CO, CO, HO, CH, N, or other components.

[0335] Some variations of the present disclosure include hydrogen isotopes 2 H / 1 To provide a reducing gas comprising at least 25 mol% hydrogen, which is at least 50% renewable hydrogen by H analysis. In some embodiments, the reducing gas comprises at least 50 mol% hydrogen, at least 75 mol% hydrogen, or at least 90 mol% hydrogen. In various embodiments, the reducing gas comprises from about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 mol% hydrogen, or any range therebetween.

[0336] In some reducing gases, hydrogen isotopes 2 H / 1 In some embodiments, the hydrogen is characterized by at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% renewable hydrogen by H analysis. 2 H / 1 H analysis shows that it features entirely (100%) renewable hydrogen.

[0337] The reducing gas can further comprise a carbon-containing gas that comprises CO, CO2, or CH4, or consists essentially of CO, CO2, or CH4. The carbon-containing gas can be 14 C / 12 The reducing gas may be at least 50% renewable, at least 90% renewable, or essentially fully renewable, as determined from measurements of the C isotope ratio. In some embodiments, the reducing gas comprises a carbon-containing gas, and the hydrogen isotope is 2 H / 1 It is characterized by at least 90% renewable hydrogen or essentially fully renewable hydrogen according to H analysis.

[0338] In some reducing gases, the reducing gas further comprises carbon monoxide, the carbon monoxide being 14 C / 12 At least 50% renewable, at least 90% renewable, or essentially fully renewable, as determined from measurements of C isotope ratios. In some embodiments, the reducing gas further comprises carbon monoxide, and the hydrogen isotope 2 H / 1 The reducing gas is characterized by at least 90% renewable hydrogen or essentially fully renewable hydrogen by H analysis. In some reducing gases, the molar ratio of hydrogen to carbon monoxide is at least 1, 1.1, 1.2, 1.3, 1.4, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0.

[0339] In some embodiments, the reducing gas comprises up to about 1 mol% N, up to about 0.5 mol% N, up to about 0.1 mol% N, or essentially no N. In various embodiments, the reducing gas comprises from about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.04, 0.03, 0.02, or 0.01 mol% N. In this disclosure, a "substantially nitrogen-free" hydrogen product means that no nitrogen detectable by conventional analytical techniques is present in the reducing gas composition.

[0340] The process disclosed herein is an environmentally friendly technology with a reduced carbon footprint. When the starting material is biomass, which contains both biological and renewable carbon, the carbon obtained by pyrolysis is also biological. This can be achieved, for example, by determining the carbon content using ASTM D6866. 14 C / 12 This can be demonstrated by measuring the C isotope ratio. In some embodiments, all of the processed carbon is renewable. In other embodiments, less than all of the carbon is renewable.

[0341] Any biogenic carbon that is oxidized to carbon dioxide produces biogenic CO2. This also reduces the carbon content in a sample of produced CO2. 14 C / 12 This can be demonstrated by measuring the C isotope ratio. This biogenic CO2 obtained from biomass is returned to the environment and reabsorbed by the growing biomass via photosynthesis. In this way, net CO2 emissions are significantly reduced. Furthermore, the hydrogen content of biomass significantly reduces net CO2 emissions in metal production. H2 can cause the chemical reduction of metal oxides in much the same way as CO2, but rather than producing CO2, the oxidation of H2 produces H2O, which is not considered a problematic greenhouse gas.

[0342] Another reason the disclosed process is environmentally superior to conventional techniques for metal production relates to the energy balance. Metal oxide reduction is inherently energy-intensive because the entire chemical reaction is endothermic. Even known electrochemical conversion approaches, which decompose metal oxides into metal and oxygen, thereby avoiding direct CO2 production, typically require large amounts of electricity generated from non-renewable resources. Traditional metal ore processing utilizes large amounts of coal to generate the necessary heat (from coal combustion) and to provide carbon for the reduction reaction. In contrast, some embodiments of the present disclosure provide an integrated bioreduction process that utilizes carbon and hydrogen in an energy-efficient manner, thereby avoiding the pollution caused by coal combustion.

[0343] Integrated bioreduction of metal ores significantly reduces environmental impact compared to the traditional use of fossil fuels such as coal. Traditional approaches are associated with a "carbon intensity," which is the net amount of carbon dioxide produced per ton of metal ore processed. "CO2-equivalent carbon intensity" can also be defined as the net amount of carbon dioxide equivalent produced per ton of metal ore processed. "Carbon dioxide equivalent" or "CO2e" represents the amount of CO2 that has an equivalent global warming impact. As an example, for iron ore processing, the average is 11.9 kg of CO2 / ton (Tost et al., "Metal Mining's Environmental Pressures: A Review and Updated Estimates on CO2 Emissions, Water Use, and Land Requirements," Sustainability 2018, 10, 2881, which is incorporated by reference). In various embodiments, the processes disclosed herein can be characterized by a carbon intensity or CO2 equivalent carbon intensity reduction of about 50%, 60%, 70%, 80%, 90%, 95%, or 99% compared to the prior art. In various embodiments, the processes disclosed herein can be characterized by a carbon intensity or CO2 equivalent carbon intensity of about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.4, 0.3, 0.2, or 0.1 kg CO2 / ton or less. In the present disclosure, most or all of the CO2 produced can be biogenic carbon dioxide, such that the effective carbon intensity is very low, zero, or negative if the carbon is net sequestered in an end product such as carbon steel.

[0344] Oxygen can be intentionally limited in the combustion of biogas to produce more CO (rather than CO in complete combustion), and the CO can then be used as a reducing agent. Producing CO by partial oxidation still generates some heat, but less heat than conventional complete oxidation to CO. These variations take advantage of the discovery that the heat generated is sufficient to perform the endothermic reduction of metal oxides, which chemically utilizes the CO produced in the partial oxidation. Some variations provide a method for optimizing the reduction of metal oxides, including pyrolysis of biomass to obtain carbon and biogas, intentionally oxidizing the biogas with less oxygen than the combustion stoichiometry, thereby generating heat and CO, and utilizing the heat and CO to reduce the metal oxides. Hydrogen produced in this process can also be used to reduce metal oxides.

[0345] A "combustion stoichiometric amount of oxygen" is the amount of oxygen, whether in air, pure oxygen, or oxygen-enriched air, that completely oxidizes carbon-containing or hydrogen-containing components to CO or HO, respectively, without stoichiometric excess. When biogas is intentionally oxidized at less than stoichiometric amounts for combustion, the ratio of utilized oxygen to the combustion stoichiometric amount of oxygen can be about 10% to about 99%, about 25% to about 90%, e.g., about 40% to about 80%. In various embodiments, this ratio is about, at least about, or at most about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. These ratios are on a molar basis based on oxygen in the O form.

[0346] In some embodiments, carbon can be used directly to reduce metal oxides, for example, by reacting the metal oxide with carbon, thereby producing the metal (or a less reduced form of the metal) and carbon monoxide or carbon dioxide. Alternatively or additionally, carbon can be used indirectly to reduce metal oxides by converting carbon to carbon monoxide and subsequently reacting the carbon monoxide with the metal oxide. In any of these embodiments for metal oxide reduction, hydrogen can also be used to reduce the metal oxide to the metal.

[0347] In some embodiments, the biocatalytic conversion reactor (represented in Figures 1-4 as the third heated vessel or heated zone) uses gasification of a biologically derived reagent, thereby producing a reducing gas. Gasification is carried out at high temperatures, such as at least about 600°C and up to about 1100°C. Less reactive biocatalysts typically require higher operating temperatures. The amount of reactants introduced (steam from recovered water, and optionally oxygen) can be the primary factor controlling the gasification temperature. Operating pressures from atmospheric pressure to about 50 bar can be used in gasification.

[0348] Gasifiers can be classified based on the means of supporting solids within the vessel, the flow direction of both solids and gases, and the method of heat delivery to the reactor. Gasifiers can operate at near atmospheric pressure or at elevated pressure. Common classifications are fixed bed upflow, fixed bed downflow, bubbling fluidized bed, and circulating fluidized bed.

[0349] Circulating fluidized bed gasification technology is available from Lurgi and Foster Wheeler and represents the majority of existing gasification technologies utilized for biomass. Bubbling fluidized bed gasification (e.g., U-GAS® technology) is also commercially available.

[0350] Directly heated gasifiers perform endothermic and exothermic gasification reactions in a single reaction vessel, eliminating the need for additional heating. In contrast, indirectly heated gasifiers use an external heat source. Indirectly heated gasifiers typically use two vessels. The first vessel gasifies the feedstock with steam (an endothermic process). Heat is provided by circulating a heat transfer medium, typically sand. The reducing gas and solid char produced in the first vessel are separated along with the sand. The combined char and sand are fed to the second vessel, where the char is combusted with air to heat the sand. The hot sand is circulated back to the first vessel.

[0351] The bio-based reagents can be introduced into the gasifier as a "dry feed" (optionally with moisture but no free liquid phase) or as a slurry or suspension in water. Dry feed gasifiers can allow for a high conversion rate of carbon to reducing gas per pass, resulting in excellent energy efficiency. In dry feed gasifiers, the energy released by the gasification reaction can cause the gasifier to reach very high temperatures. This problem can be solved by using a wet wall design.

[0352] In some embodiments, a hydrogen-rich biocatalyst is fed to a gasifier, and the resulting reduced gas is relatively rich in hydrogen, with a high H2 / CO ratio, e.g., H2 / CO 1.5 or greater.

[0353] In some embodiments, a biocatalyst with low hydrogen content is fed to the gasifier. When steam from the recovered water is blown into the gasifier, it can moderate the gasifier temperature (through sensible heat effect or endothermic chemistry) and shift the H2 / CO ratio to a higher, more desirable ratio. The addition of water can also contribute to temperature moderation through endothermic dissipation. In biocatalytic conversion, HO reacts with carbon or hydrocarbons such as tar or benzene / toluene / xylene to produce reducing gases, lowering the adiabatic gasification temperature.

[0354] In certain variations, the gasifier is a fluidized bed gasifier, e.g., a bubbling fluidized bed gasification reactor. Fluidization results in a nearly uniform temperature within the gasifier bed. Fluidized bed materials, such as alumina sand or silica sand, can mitigate potential attrition problems. The gasifier temperature can be adjusted to a low enough temperature so that the ash particles do not begin to change from a solid to a molten state, which can cause agglomeration and loss of fluidity within the gasifier.

[0355] When using a fluidized bed gasifier, the total flow rate of all components should ensure that the gasifier bed is fluidized. The total gas flow rate and bed diameter determine the gas velocity through the gasifier. The correct velocity must be maintained to ensure proper fluidization.

[0356] In some variations, the gasifier type can be entrained flow slagging, entrained flow non-slagging, conveying, bubbling fluidized bed, circulating fluidized bed, or fixed bed. In some embodiments, a gasification catalyst other than a biocatalyst (e.g., a metal catalyst such as nickel) is used.

[0357] A circulating fluidized bed gasifier can be used, with gas, sand, and feedstock moving together. Exemplary transport gases include recycled product gas, combustion gas, or recycled gas. The high heat transfer rate from the sand ensures that the feedstock heats up quickly, resulting in stronger ablation than in a conventional fluidized bed. A separator can be used to separate the reducing gas from the sand and char particles. The sand particles can be reheated in a fluidized burner vessel and recycled to the reactor.

[0358] In some embodiments using a countercurrent fixed-bed gasifier, the reactor contains a fixed bed of feedstock through which the gasifying agent (steam, oxygen, or a combination thereof) flows in a countercurrent configuration. Ash is removed dry or as a slag.

[0359] In some embodiments using a co-current fixed-bed gasifier, the reactor is similar to a counter-current type, but the gasifying agent gas flows in a co-current configuration with the feedstock. Heat is added to the top of the bed by burning a small amount of the feedstock or from an external heat source. The produced gas exits the reactor at a high temperature, and much of this heat is transferred to the gasifying agent added to the top of the bed, resulting in good energy efficiency.

[0360] In some embodiments using a fluidized bed reactor, the feedstock is fluidized in recycled gas, oxygen, air, or steam. The ash can be removed dry or as heavy agglomerates that lose fluidity. Recycling or subsequent combustion of the solids can be used to increase conversion. Fluidized bed reactors are useful for feedstocks that form highly corrosive ash that can damage the walls of a slag reactor.

[0361] In some embodiments using an entrained flow gasifier, the biogenic reagent is gasified in co-current with steam and optionally oxygen, with optional gas recycling. The gasification reaction occurs in a dense cloud of very fine particles. High temperatures can be used, thereby providing low amounts of tar and methane in the reducing gas.

[0362] Entrained-bed reactors remove most of the ash as slag because their operating temperatures are well above the ash melting point. A small amount of ash is produced as either very fine dry fly ash or fly ash slurry. Certain entrained-bed reactors have water- or steam-cooled inner walls that are partially coated with solidified slag.

[0363] The gasifier chamber can be designed with appropriate freeboard configuration or the use of internal cyclones to maintain solids carryover to downstream operations at a level suitable for heat recovery. Unreacted solids are withdrawn from the bottom of the gasifier chamber, cooled, and can be recovered.

[0364] In some embodiments, a bubbling fluidized bed devolatilization reactor is utilized as a third heated vessel or heated zone. The vessel is at least partially heated by a hot recycle gas stream to about 600°C, below the expected slagging temperature of the biomass.

[0365] A third heating vessel or heating zone can be designed by appropriate configuration of the freeboard or use of internal cyclones to maintain solids carryover at a level suitable for downstream heat recovery. Unreacted carbon is withdrawn from the bottom of the devolatilization chamber and, after cooling, can be fed to a utility boiler to recover the remaining heating value of this stream.

[0366] When a fluidized-bed gasifier is used as the third heating vessel or heating zone, the feedstock can be introduced into a bed of hot sand fluidized by a gas, such as recycled gas. References to "sand" herein also include similar substantially inert materials, such as glass particles and recycled ash particles. The high rate of heat transfer from the fluidized sand can rapidly heat the feedstock. Friction with the sand particles can cause some abrasion. Heat can be provided by heat exchange tubes through which hot combustion gases flow.

[0367] A circulating fluidized bed reactor can be used as a third heating vessel or heating zone, with the gas, sand, and feedstock moving together. Exemplary transport gases include recycled product gas, combustion gas, or recycled gas. The high heat transfer rate from the sand ensures that the feedstock heats up rapidly, resulting in stronger ablation than in a conventional fluidized bed. A separator can be used to separate the reducing gas from the sand and char particles. The sand particles can be reheated in the fluidized burner vessel and recycled to the reactor.

[0368] In some embodiments using a countercurrent fixed-bed reactor as the third heating vessel or heating zone, the reactor contains a fixed bed of feedstock through which the gasifying agent (steam and optionally oxygen) flows in a countercurrent configuration. Ash is removed dry or as a slag.

[0369] In some embodiments using a co-current fixed-bed reactor as the third heating vessel or heating zone, the reactor is similar to the countercurrent type, but the gasifying agent flows in a co-current configuration with the feedstock. Heat is added to the top of the bed by burning a small amount of the feedstock or from an external heat source. The reducing gas exits the reactor at a high temperature, and much of this heat is transferred to the reactants added to the top of the bed, resulting in good energy efficiency. Because the tar passes through the hot bed of carbon in this configuration, tar levels are expected to be lower than when using a countercurrent type.

[0370] In some embodiments using a fluidized bed reactor as the third heating vessel or heating zone, the feedstock is fluidized in steam and optionally other gases (e.g., O, N, etc.). Ash is removed dry or as heavy agglomerates that lose fluidity. Recycling or subsequent combustion of the solids can be used to increase conversion.

[0371] Water can be introduced into the third heating vessel or heating zone, for example, in the form of steam or as droplets. To improve heat and mass transfer, water can be introduced into the third heating vessel or heating zone using a nozzle, which is generally a mechanical device designed to control the direction or characteristics of fluid flow as it enters an enclosed chamber or pipe through an orifice. The nozzle can reduce the size of the water droplets, thereby producing a fine water spray. The nozzle can be selected from atomizer nozzles (similar to fuel injectors), swirl nozzles that inject liquid tangentially, and the like.

[0372] The recovered water from the first heating vessel or zone or the second heating vessel or zone may first be optionally washed, purified, treated, ionized, distilled, etc., before being supplied to the third heating vessel or zone. Typically, but not necessarily, additional water (in addition to the recovered water) may be added to the third heating vessel or heating zone. Additional water sources may include, for example, process condensate, other recycled water, wastewater, make-up water, boiler feedwater, or direct piping from city water.

[0373] In some variations, the reducing gas from the third heated vessel or heated zone is filtered, purified, or conditioned before being converted to another product. For example, the cooled reducing gas can be introduced into a conditioning unit where benzene, toluene, ethylbenzene, xylene, sulfur compounds, nitrogen, metals, or other impurities are optionally removed from the reducing gas.

[0374] Some embodiments of the present disclosure include a reducing gas purification unit downstream of the third heating vessel or heating zone. The reducing gas purification unit is not particularly limited to this design. Exemplary reducing gas purification units include cyclones, centrifuges, filters, membranes, solvent-based systems, and other means for removing particulates or other specific contaminants.

[0375] In some embodiments, an acid gas removal unit is included downstream of the third heating vessel or heating zone. The acid gas removal unit is not particularly limited and can be any means known in the art for removing H2S, CO2, or other acid gases from the reducing gas.

[0376] Examples of acid gas removal steps include, for example, removal of CO using one or more solvents for CO or removal of CO by a pressure swing adsorption unit. Suitable solvents for reactive solvent-based acid gas removal include monoethanolamine, diethanolamine, methyldiethanolamine, diisopropylamine, and aminoethoxyethanol. Suitable solvents for physical solvent-based acid gas removal include dimethyl ether of polyethylene glycol (e.g., in the Selexol® process) and refrigerated methanol (e.g., in the Rectisol® process).

[0377] The reducing gas produced as described in this disclosure can be utilized in a variety of ways. The reducing gas is generally chemically converted or purified to hydrogen, carbon monoxide, methane, olefins (such as ethylene), oxygenates (such as dimethyl ether), alcohols (such as methanol and ethanol), paraffins, and other hydrocarbons. The reducing gas can be converted to straight or branched chain C5-C6 hydrocarbons by Fischer-Tropsch chemistry. 15 It can be converted to hydrocarbons, diesel fuel, gasoline, waxes, or olefins, to mixed alcohols by various catalysts, to isobutane by isosynthesis, to hydrogen production and ammonia by the Haber process, to aldehydes and alcohols by oxosynthesis, and to many derivatives of methanol, including dimethyl ether, acetic acid, ethylene, propylene, and formaldehyde, by various processes. The reducing gas can also be converted to energy using energy conversion devices such as solid oxide fuel cells, Stirling engines, microturbines, internal combustion engines, thermoelectric generators, scroll expanders, gas burners, or thermophotovoltaic devices.

[0378] Activated carbon recovery Now, further discussion of activated carbon recovery is provided. In some embodiments, step (f) is performed to intentionally or accidentally produce an activated carbon by-product. At least 1 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, or 90 wt% of the biocatalyst produced in step (b) can be recovered as activated carbon. The process can be tuned to produce more or less activated carbon compared to the carbon sent to the reducing gas.

[0379] In certain embodiments, the fixed carbon within the biocatalyst can be used primarily to produce activated carbon, while the volatile carbon within the biocatalyst can be used primarily to produce a reducing gas. For example, at least 50 wt%, at least 90 wt%, or essentially all of the fixed carbon within the biocatalyst produced in step (b) can be recovered as activated carbon in step (f), while at least 50 wt%, at least 90 wt%, or essentially all of the volatile carbon within the biocatalyst produced in step (b) can be sent to the reducing gas.

[0380] Activated carbon is activated carbon 14 C / 12 The activated carbon may be characterized by a renewable carbon content of at least 50%, 60%, 70%, 80%, 90%, or 95% as determined from C isotope ratio measurements. 14 C / 12 Characterized by (fully) renewable activated carbon as determined from C isotope ratio measurements.

[0381] In some systems, the third heating vessel or heating zone is configured to continuously or periodically remove the activated carbon from the third heating vessel or heating zone, for example, via a screw conveyor to remove carbon pellets, powder, or objects from the reactor. In these or other embodiments, the third heating vessel or heating zone is configured to eventually remove the activated carbon from the third heating vessel or heating zone (i.e., at the end of the reaction time), for example, via a screw conveyor or by opening the reactor from the top to recover the activated carbon.

[0382] In some embodiments, the third heating vessel or heating zone is configured to optimize the production of different types of activated carbon. For example, reaction conditions (e.g., time, temperature, and steam concentration) can be selected for activated carbon products with specific attributes, such as iodine value. Different reaction conditions can be selected for different activated carbon products, such as products with high iodine values. The third heating vessel or heating zone can operate in a campaign mode to produce one product and then switch to a different mode for a different product. The first product can be removed continuously or periodically during the first campaign and before switching the reaction conditions in the third heating vessel or heating zone. In general, the third heating vessel or heating zone can be optimized for the production of different amounts and characteristics of activated carbon and different amounts and qualities of reducing gas.

[0383] The activated carbon produced by the processes disclosed herein can be used in a number of applications.

[0384] In some embodiments, activated carbon is utilized internally at a process site to purify one or more primary products. In some embodiments, activated carbon is utilized on-site to purify water. In these or other embodiments, activated carbon is utilized on-site to treat liquid waste streams to reduce liquid-phase emissions or to treat vapor waste streams to reduce air emissions. In some embodiments, activated carbon is utilized as a soil amendment to generate new biomass, which can be of the same type as the biomass utilized on-site as a local feedstock.

[0385] Activated carbon produced according to the processes disclosed herein can have properties comparable to or better than conventional fossil-fuel-based activated carbon. In some embodiments, the activated carbon has a surface area comparable to, equal to, or greater than that associated with fossil-fuel-based activated carbon. In some embodiments, the activated carbon can suppress contaminants at a rate comparable to or better than conventional activated carbon products. In some embodiments, the activated carbon has inert (e.g., ash) levels comparable to, equal to, or lower than that associated with conventional activated carbon products. In some embodiments, the activated carbon has a particle size or particle size distribution comparable to, equal to, greater than, or smaller than that associated with conventional activated carbon products. In some embodiments, the activated carbon has a particle shape comparable to, substantially similar to, or the same as that associated with conventional activated carbon products. In some embodiments, the activated carbon has a particle shape that is substantially different from that associated with conventional activated carbon products. In some embodiments, the activated carbon has a pore volume comparable to, equal to, or greater than that associated with conventional activated carbon products. In some embodiments, the activated carbon has pore sizes comparable to, substantially similar to, or the same as those associated with conventional activated carbon products. In some embodiments, the activated carbon has particle attrition resistance comparable to, substantially similar to, or the same as that associated with conventional activated carbon products. In some embodiments, the activated carbon has hardness comparable to, substantially similar to, or the same as that associated with conventional activated carbon products. In some embodiments, the activated carbon has bulk density values ​​comparable to, substantially similar to, or the same as that associated with conventional activated carbon products. In some embodiments, the activated carbon product has adsorption capacities comparable to, substantially similar to, or the same as that associated with conventional activated carbon products.

[0386] The disclosed activated carbons can be analyzed, measured, and optionally modified (e.g., with additives) in a variety of ways to suit any product application or prior to actual use. Some properties of potential interest include density, particle size, surface area, microporosity, absorption, adsorption, binding capacity, reactivity, desulfurization activity, basicity, hardness, and iodine number.

[0387] Activated carbon is used commercially in a variety of liquid and gas phase applications, including water treatment, air purification, solvent vapor recovery, food and beverage processing, sugar and sweetener refining, automotive applications, and pharmaceuticals. For activated carbon, important product attributes can include particle size, shape, composition, surface area, pore volume, pore dimensions, particle size distribution, carbon surface and internal chemistry, particle attrition resistance, hardness, bulk density, and adsorption capacity.

[0388] The bulk density of the activated carbon can be, for example, about 50 g / liter to about 650 g / liter.

[0389] The surface area of ​​activated carbon can vary widely. An exemplary surface area is about 400 m 2 / g~about 2000m 2 / g or more, for example, about 500m 2 / g, 600m 2 / g, 800m 2 / g, 1000m 2 / g, 1200m 2 / g, 1400m 2 / g, 1600m 2 / g or 1800m 2 / g. Surface area generally correlates with adsorption capacity.

[0390] Pore ​​size distribution can be important in determining the ultimate performance of activated carbon. Pore size measurements can include micropore content, mesopore content, and macropore content.

[0391] Iodine number is a parameter used to characterize the performance of activated carbon. It measures the degree of activation of the carbon and is a measure of the micropore (e.g., 0-20 Å) content. It is an important measurement in liquid-phase applications. Exemplary iodine numbers for activated carbon products produced by embodiments of the present disclosure include ranges from or between about 500, 600, 750, 900, 1000, 1100, 1200, 1300, 1500, 1600, 1750, 1900, 2000, 2100, and 2200. The units of iodine number are milligrams of iodine per gram of carbon.

[0392] Another pore-related measurement is the methylene blue number, which measures mesopore content (e.g., 20-500 Å). Exemplary methylene blue numbers for activated carbon products produced according to embodiments of the present disclosure include ranges from or between about 100, 150, 200, 250, 300, 350, 400, 450, and 500. The units of methylene blue number are milligrams of methylene blue (methylthioninium chloride) per gram of carbon.

[0393] Another pore-related measurement is molasses number, which measures macropore content (e.g., >500 Å). Exemplary molasses numbers for activated carbon products produced according to embodiments of the present disclosure include ranges from or between about 100, 150, 200, 250, 300, 350, and 400. The units of molasses number are milligrams of molasses per gram of carbon.

[0394] Activated carbon can be characterized by its water retention capacity. In various embodiments, activated carbon products produced according to embodiments of the present disclosure have a water retention capacity at 25° C. of about 10% to about 300% (weight of water divided by weight of dry activated carbon), e.g., about 50% to about 100%, e.g., about 60-80%.

[0395] Hardness, or abrasion value, is a measure of the abrasion resistance of activated carbon. It is an indicator of the physical integrity of activated carbon to withstand frictional forces and mechanical stresses during handling or use. While a certain degree of hardness is desirable, too much hardness can cause excessive equipment wear. Exemplary abrasion values ​​measured in accordance with ASTM D3802 range from about 1% to greater than about 99%, such as about 1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 96%, about 97%, about 98%, about 99%, or at least about 99%.

[0396] In some embodiments, an optimal hardness range can be achieved where the activated carbon is reasonably attrition resistant but does not cause wear and tear on the capital equipment that processes the activated carbon. This optimization can be achieved in some embodiments of the present disclosure through feedstock selection and processing conditions. In some embodiments where downstream applications can accommodate high hardness, the processes of the present disclosure can be operated to increase or maximize hardness to produce a bio-based activated carbon product with an attrition value of about 75%, about 80%, about 85%, about 90%, about 95%, about 96%, about 97%, about 98%, about 99%, or at least about 99%.

[0397] The biogenic activated carbon provided by the present disclosure has a wide range of commercial applications, including, but not limited to, emission control, water purification, groundwater treatment, wastewater treatment, air stripper applications, PCB removal applications, odor removal applications, soil vapor extraction, manufactured gas plants, industrial water filtration, industrial fumigation, tank and process vents, pumps, blowers, filters, pre-filters, mist filters, ducts, piping modules, adsorbers, absorbers, and columns.

[0398] In one embodiment, the method for reducing emissions using activated carbon comprises: (a) providing activated carbon particles comprising a biogenic activated carbon composition recovered from a reactor as disclosed herein; (b) providing a gas-phase effluent stream containing the selected contaminant; (c) providing an additive selected to assist in the removal of the selected contaminant from the gas phase effluent stream; (d) introducing activated carbon particles and an additive into the gaseous effluent stream, thereby adsorbing selected contaminants onto the activated carbon particles, thereby producing contaminant-adsorbed carbon particles in the gaseous effluent stream; (e) separating the contaminant-adsorbed carbon particles from the gas-phase exhaust stream, thereby producing a contaminant-reduced gas-phase exhaust stream.

[0399] The additive for the biogenic activated carbon composition can be provided as part of the activated carbon particles. Alternatively or additionally, the additive can be introduced directly into the gas-phase exhaust stream, fuel bed, or combustion zone. As will be appreciated by those skilled in the art, other methods of directly or indirectly introducing the additive into the gas-phase exhaust stream to remove selected pollutants are possible.

[0400] The selected contaminant (in the gas-phase effluent stream) is a metal, such as mercury, boron, selenium, arsenic, or any compound, salt, or mixture thereof. The selected contaminant can be, for example, a hazardous air pollutant, an organic compound (e.g., a VOC), or a non-condensable gas. In some embodiments, the biogenic activated carbon product adsorbs, absorbs, or chemisorbs more of the selected contaminant than an equivalent amount of a non-biogenic activated carbon product. In some such embodiments, the selected contaminant is a metal, a hazardous air pollutant, an organic compound (e.g., a VOC), a non-condensable gas, or any combination thereof. In some embodiments, the selected contaminant comprises mercury. In some embodiments, the selected contaminant comprises one or more VOCs. In some embodiments, the biogenic activated carbon comprises at least about 1 wt% hydrogen or at least about 10 wt% oxygen.

[0401] Hazardous air pollutants are those pollutants that cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse effects on the environment and ecosystems. Section 112 of the Clean Air Act, as amended, is incorporated herein by reference in its entirety. Under Section 112 of the Clean Air Act, the U.S. Environmental Protection Agency (EPA) is required to regulate 189 hazardous air pollutants. Any current or future compound classified by the EPA as a hazardous air pollutant is included as a possible select pollutant in this context.

[0402] Volatile organic compounds (VOCs), some of which are hazardous air pollutants, are organic chemicals that have a high vapor pressure under normal room temperature conditions. Examples include short-chain alkanes, olefins, alcohols, ketones, and aldehydes. Many VOCs are hazardous to human health or cause adverse environmental effects. The EPA regulates VOCs in air, water, and soil. The EPA's definition of VOCs is set forth in 40 CFR 51.100, the entire contents of which are incorporated herein by reference.

[0403] Non-condensable gases are gases that do not condense under normal room temperature conditions and can include, but are not limited to, nitrogen oxides, carbon monoxide, carbon dioxide, hydrogen sulfide, sulfur dioxide, sulfur trioxide, methane, ethane, ethylene, ozone, ammonia, or combinations thereof.

[0404] Multiple contaminants can be removed by the disclosed activated carbon particles. In some embodiments, the contaminant-loaded carbon particles include at least two contaminants, at least three contaminants, or more contaminants. The activated carbons disclosed herein can enable multi-contaminant control and specific target contaminant control (e.g., selenium).

[0405] In some embodiments, the contaminant-loaded carbon particles are treated to regenerate activated carbon particles. In some embodiments, the method includes thermally oxidizing the contaminant-loaded carbon particles. The contaminant-loaded carbon particles or a regenerated form thereof can be combusted to provide energy.

[0406] In some embodiments, the additive for the activated carbon is selected from an acid, a base, a salt, a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof. In certain embodiments, the additive is selected from magnesium, manganese, aluminum, nickel, iron, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorite, bentonite, calcium oxide, lime, sodium hydroxide, potassium hydroxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, an organic acid (e.g., citric acid), or a combination thereof.

[0407] In some embodiments, the gas phase effluent stream is obtained from metal processing, such as processing of high sulfur content metal ores.

[0408] In an exemplary embodiment for mercury control, activated carbon can be injected (e.g., into a duct) upstream of a particulate matter control device such as an electrostatic precipitator or fabric filter. In some cases, a flue gas desulfurization (dry or wet) system can be downstream of the activated carbon injection point. The activated carbon can be injected pneumatically as a powder. The injection location can be determined by the existing plant configuration (excluding new locations) and whether additional downstream particulate matter control devices have been modified.

[0409] Currently, implementing biogenic activated carbon injection for mercury control in boilers equipped with particulate matter control devices can involve (i) injecting powdered activated carbon upstream of the existing particulate matter control device (electrostatic precipitator or fabric filter), (ii) injecting powdered activated carbon downstream of the existing electrostatic precipitator and upstream of a retrofit fabric filter, or (iii) injecting powdered activated carbon between the electric fields of the electrostatic precipitator. The addition of iron or iron-containing compounds can significantly improve the performance of electrostatic precipitators for mercury control. Furthermore, the addition of iron or iron-containing compounds can significantly alter end-of-life options by separating spent activated carbon solids from other ash.

[0410] In some embodiments, powdered activated carbon injection can be employed in combination with existing SO2 control equipment. The activated carbon can be injected before the SO2 control equipment or after the SO2 control equipment, and means are available to recover the activated carbon sorbent downstream of the injection point.

[0411] In some embodiments, the same physical material can be used in multiple processes in an integrated or sequential manner, so for example, activated carbon may then be introduced as a high performance material at the end of its useful life into a combustion process to obtain its energy value, or into a metal manufacturing process or the like that uses carbon but does not require the properties of activated carbon.

[0412] Biogenic activated carbon and the principles of the present disclosure can be applied to liquid phase applications, including, for example, the processing of water, aqueous streams of various purities, solvents, liquid fuels, polymers, molten salts, and molten metals. As intended herein, "liquid phase" includes slurries, suspensions, emulsions, multi-phase systems, or any other material in which a certain amount of liquid state exists (or can be adjusted to exist).

[0413] In one embodiment, the present disclosure provides a method for purifying a liquid using activated carbon, the method comprising: (a) providing activated carbon particles recovered from a reactor; (b) providing a liquid containing the selected contaminant; (c) providing an additive selected to assist in the removal of the selected contaminant from the liquid; (d) contacting the liquid with the activated carbon particles and the additive, thereby adsorbing the selected contaminants onto the activated carbon particles, thereby producing contaminant-adsorbed carbon particles and a contaminant-reduced liquid.

[0414] The additive can be provided as part of the activated carbon particles, or the additive can be introduced directly into the liquid. In some embodiments, the additive is introduced directly into the liquid as part of the activated carbon particles.

[0415] In some embodiments for liquid-phase applications, the additive is selected from an acid, a base, a salt, a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof. For example, the additive can be selected from magnesium, manganese, aluminum, nickel, iron, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorspar, bentonite, calcium oxide, lime, sodium hydroxide, potassium hydroxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, an organic acid (e.g., citric acid), or a combination thereof.

[0416] In some embodiments, the selected contaminant (in the liquid to be treated) is a metal, such as a metal selected from arsenic, boron, selenium, mercury, or any compound, salt, or mixture thereof. In some embodiments, the selected contaminant is an organic compound (e.g., a VOC), a halogen, a biological compound, a pesticide, or a herbicide. The contaminant-adsorbed carbon particles can contain two, three, or more contaminants. In some embodiments, the activated carbon product adsorbs, absorbs, or chemisorbs more of the selected contaminant than an equivalent amount of a non-biogenic activated carbon product. In some such embodiments, the selected contaminant is a metal, a hazardous air pollutant, an organic compound (e.g., a VOC), a non-condensable gas, or any combination thereof. In some embodiments, the selected contaminant comprises mercury. In some embodiments, the selected contaminant comprises one or more VOCs. In some embodiments, the biogenic activated carbon comprises at least about 1 wt% hydrogen or at least about 10 wt% oxygen.

[0417] The liquid to be treated can be aqueous, although this is not required by the principles of the present disclosure. In some embodiments, the liquid is treated with activated carbon particles in a fixed bed. In other embodiments, the liquid is treated with activated carbon particles in a solution or moving bed.

[0418] In one embodiment, the present disclosure provides a method for removing sulfur-containing contaminants from a liquid using a biogenic activated carbon composition, the method comprising: (a) providing activated carbon particles recovered from a reactor as disclosed herein; (b) providing a liquid containing sulfur-containing contaminants; (c) providing an additive selected to assist in the removal of sulfur-containing contaminants from the liquid; (d) contacting the liquid with the activated carbon particles and the additive, thereby causing the sulfur-containing contaminants to be adsorbed or absorbed onto or into the activated carbon particles.

[0419] In some embodiments, the sulfur-containing contaminant is selected from elemental sulfur, sulfate, sulfite, sulfur dioxide, sulfur trioxide, sulfate anion, bisulfate anion, sulfite anion, bisulfite anion, thiol, sulfide, disulfide, polysulfide, thioether, thioester, thioacetal, sulfoxide, sulfone, thiosulfinate, sulfimide, sulfoximide, sulfondiimine, sulfur halide, thioketone, thioaldehyde, sulfur oxide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, sulfenic acid, sulfonium, oxosulfonium, sulfurfuran, persulfuran, or a combination, salt, or derivative thereof. For example, the sulfur-containing contaminant can be sulfate in the form of an anion or salt.

[0420] The liquid can be an aqueous liquid such as water. In some embodiments, the water is wastewater associated with a process selected from metal mining, acid mine drainage, mineral processing, municipal sewage treatment, pulp and paper, ethanol, or any other industrial process that may discharge sulfur-containing contaminants into the wastewater. The water can also be (or a portion thereof) of a natural body of water such as a lake, river, or stream.

[0421] In one embodiment, the present disclosure provides a process for reducing the concentration of sulfate in water, the process comprising: (a) providing activated carbon particles recovered from a reactor as disclosed herein; (b) providing a quantity or stream of water containing sulfate; (c) providing an additive selected to assist in the removal of sulfates from the water; (d) contacting the water with the activated carbon particles and the additive, thereby causing the sulfate to be adsorbed or absorbed onto or into the activated carbon particles.

[0422] In some embodiments, sulfate is reduced to a concentration of about 50 mg / L or less in water, for example, to a concentration of about 10 mg / L or less in water. In some embodiments, sulfate is present primarily in the form of sulfate or bisulfate anions. Depending on the pH, sulfate can also be present in the form of sulfate salts.

[0423] The water can be obtained from a wastewater stream, some or all of which may be present. Exemplary wastewater streams are those that may be associated with metal mining, acid mine drainage, mineral processing, municipal sewage treatment, pulp and paper, ethanol, or other industrial processes that may discharge sulfur-containing contaminants into the wastewater. The water can be a natural body of water, such as a lake, river, or stream. In some embodiments, the process is performed continuously. In other embodiments, the process is performed in batches.

[0424] Treating water with activated carbon can involve water filtration, water permeation, or direct addition of activated carbon particles to water (by precipitation, clarification, etc.). When permeation is used, activated carbon can be used in a variety of ways within or to support the permeation device. In some embodiments, activated carbon particles and additives are directly introduced into the water prior to permeation. Activated carbon particles and additives are optionally used in pre-filtration prior to permeation. In certain embodiments, activated carbon particles and additives are incorporated into a membrane for permeation.

[0425] The present disclosure also provides a method for removing sulfur-containing contaminants from a gas phase using a biogenic activated carbon composition, the method comprising: (a) providing activated carbon particles recovered from a reactor as disclosed herein; (b) providing a gas-phase effluent stream comprising sulfur-containing contaminants; (c) providing an additive selected to assist in the removal of sulfur-containing contaminants from the gas-phase effluent stream; (d) introducing the activated carbon particles and the additive into the gas-phase exhaust stream, thereby adsorbing or absorbing the sulfur-containing contaminants onto the activated carbon particles; (e) separating the activated carbon particles from the gas-phase exhaust stream.

[0426] In some embodiments, the sulfur-containing contaminant is selected from elemental sulfur, sulfuric acid, sulfurous acid, sulfur dioxide, sulfur trioxide, sulfate anion, bisulfate anion, sulfite anion, bisulfite anion, thiol, sulfide, disulfide, polysulfide, thioether, thioester, thioacetal, sulfoxide, sulfone, thiosulfinate, sulfimide, sulfoximide, sulfondiimine, sulfur halide, thioketone, thioaldehyde, sulfur oxide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, sulfenic acid, sulfonium, oxosulfonium, sulfurfuran, persulfuran, or a combination, salt, or derivative thereof.

[0427] Generally speaking, the disclosed activated carbons can be used in any application where conventional activated carbons might be used. In some embodiments, the activated carbons are used as a complete (i.e., 100%) replacement for conventional activated carbons. In some embodiments, the activated carbons constitute essentially all or substantially all of the activated carbon used in a particular application. In some embodiments, the activated carbons constitute from about 1% to about 100% of the bio-based activated carbon.

[0428] For example, but not by way of limitation, activated carbon can be used alone or in combination with conventional activated carbon products in filters. In some embodiments, a packed bed or packed column contains the disclosed activated carbon. In such embodiments, the biologically derived activated carbon has size characteristics suitable for the particular packed bed or column. Injecting biomass activated carbon into a gas stream can be useful for controlling pollutant emissions in gas or liquid streams obtained from coal-fired power plants, biomass-fired power plants, metal processing plants, crude oil refineries, chemical plants, polymer plants, pulp and paper mills, cement plants, waste incinerators, food processing plants, gasification plants, and syngas plants.

[0429] Metal Oxide Reduction Furnace Various embodiments using metal ore furnaces or chemical reduction furnaces will now be further described.

[0430] The metal ore furnace or chemical reduction furnace can be a blast furnace, a top gas recirculating blast furnace, a shaft furnace, a reverberatory furnace (also called an air furnace), a crucible furnace, a silencer furnace, a retort furnace, a flash furnace, a Tecnored furnace, an Ausmelt furnace, an ISASMELT furnace, a puddle furnace, a bogie furnace, a continuous chain furnace, a pusher furnace, a rotary furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, a direct reduction metal furnace, or a combination or derivative thereof.

[0431] Metal ore furnaces or chemical reduction furnaces can be positioned horizontally, vertically or inclined. The flow of solids and fluids (liquid or gas) can be co-current or counter-current. The solids in the furnace can be in a fixed bed or a fluidized bed. Metal ore furnaces or chemical reduction furnaces can operate at a variety of process conditions: temperature, pressure and residence time.

[0432] Some variations of the present disclosure relate specifically to blast furnaces. A blast furnace is a type of metallurgical furnace used in smelting to produce industrial metals such as iron or copper. Blast furnaces are utilized to smelt iron ore to produce pig iron, an intermediate raw material used in the production of commercial steel. Blast furnaces are also used in conjunction with sinter plants, for example, in the smelting of base metals.

[0433] "Blasting" refers to the forced or supplied combustion air above atmospheric pressure. In a blast furnace, metal ore, carbon (in this disclosure, a biological reagent or its derivative), and typically a flux (e.g., limestone) are continuously fed through the top of the furnace, while a blast of hot air (optionally with oxygen enrichment) is blown into the lower part of the furnace through a series of pipes called tuyere. As the materials fall downward, chemical reduction reactions occur throughout the furnace. The end products are typically molten metal and a slag phase removed from the bottom, and waste gas (reduction off-gas) discharged from the top of the furnace. The downward flow of metal ore in countercurrent contact with the rising flow of hot CO2-rich gas allows for efficient chemical reactions to occur, reducing the metal ore to metal.

[0434] Air furnaces (e.g., reverberatory furnaces) are usually naturally aspirated by convection of hot gases in the chimney flue. By this broad definition, iron bloomery, tin blowing furnaces, and lead smelters are classified as blast furnaces.

[0435] Blast furnaces remain an important part of modern iron production. Modern blast furnaces are highly efficient, including a cowper stove that uses waste heat from the exhaust gases to preheat the incoming blast air and a recovery system that extracts heat from the hot gases exiting the blast furnace. Blast furnaces are constructed as tall structures lined with refractory bricks and can be shaped to expand as the feedstock heats and moves downward, then contract as it begins to melt.

[0436] In some embodiments related to iron production, bioreagents including renewable carbon, iron ore (iron oxide), and limestone flux are charged to the top of a blast furnace. The blast furnace can be configured to allow hot, dirty gases with high carbon monoxide content to be exhausted from the furnace throat, while a bleed valve protects the top of the furnace from sudden increases in gas pressure. Coarse particles in the exhaust gas are settled and discarded, while the gas can pass through a venturi scrubber, electrostatic precipitator, or gas cooler to reduce the temperature of the purified gas. The casting chamber at the bottom of the furnace is equipped with equipment for casting molten iron and slag. A taphole is drilled through a refractory plug so that the molten iron and slag flow down a trough through the opening, separating the pig iron and slag. After the pig iron and slag are tapped, the taphole is plugged with fireclay. A nozzle called a tuyere is used to blow hot air into the blast furnace to increase its efficiency. Hot air is introduced into the furnace through cooled tuyeres near the bottom of the furnace. The temperature of the hot air can be, for example, 900°C to 1300°C (air temperature). Temperatures within the blast furnace can be 2000°C or higher. Other carbonaceous materials or oxygen can also be blown into the furnace at the tuyeres level to increase the proportion of reducing gases present, which combine with the carbon (from the biogenic reagents) to release additional energy and increase productivity.

[0437] Blast furnaces operate on the principle of chemical reduction, with carbon monoxide, which has a stronger affinity for oxygen in metal ores (e.g., iron ore) than for the corresponding metals, reducing the metals to their elemental state. Blast furnaces differ from bloomery and reverberatory furnaces in that in a blast furnace, the exhaust gases come into direct contact with the ore and metal, and the carbon monoxide diffuses into the ore, reducing the metal oxides to elemental metal mixed with carbon. Blast furnaces typically operate as a continuous countercurrent exchange process.

[0438] Silica is typically removed from the pig iron. It reacts with calcium oxide to form silicates that float to the surface of the molten pig iron as slag. The downward-moving column of metal ores, fluxes, carbon, and reaction products must be porous enough to allow the exhaust gases to pass through. This requires that the particles of the biogenic reagent, carbon, be large enough to be permeable. Therefore, the biogenic reagent (which may contain additives) must be strong enough to not be crushed by the weight of the materials above it. In addition to the physical strength of carbon, sulfur, phosphorus, and ash can also be reduced.

[0439] Many chemical reactions occur in blast furnaces. These reactions can be understood with reference to hematite (Fe2O3) as the starting metal oxide. This form of iron oxide is common during iron ore processing, either in the initial feedstock or as produced in the blast furnace. Other forms of iron ore (e.g., taconite) contain varying concentrations of different iron oxides, such as Fe3O4, Fe2O3, and FeO.

[0440] The overall main chemical reaction that produces molten iron in a blast furnace is:

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[0441] It is important to note that in the chemical reactions shown above, the reducing gas can alternatively or additionally be introduced directly into the blast furnace rather than being an in situ product within the furnace. In these embodiments, the reducing gas can include both hydrogen and carbon monoxide, both of which function to chemically reduce metal oxides.

[0442] In conventional blast furnaces, there is no available hydrogen to drive the reduction of metal oxides. In the present disclosure, hydrogen can be injected directly into the blast furnace. Alternatively or additionally, hydrogen can be available within the bio-based reagent fed to the blast furnace if the bio-based reagent contains volatile carbon (e.g., heavy tar components) associated with hydrogen. Regardless of its source, hydrogen can drive additional reduction reactions similar to those described above, but replacing CO with H2.

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[0443] The "pig iron" produced by a blast furnace can have a relatively high carbon content, approximately 3-6 wt%. Pig iron can be used to make cast iron. Pig iron produced by a blast furnace typically undergoes further processing to reduce the carbon and sulfur content and to produce the various grades of steel used commercially. In a further processing step called basic oxygen steelmaking, oxygen is blown into the molten pig iron to oxidize the carbon and form crude steel.

[0444] Desulfurization is accomplished by adding calcium oxide, which reacts with iron sulfide contained in the molten pig iron during transportation of the pig iron to form calcium sulfide. In some embodiments, desulfurization can also be accomplished in the furnace or downstream of the furnace by reacting metal sulfides with CO (in a reducing gas) to form metal and carbonyl sulfide (CSO). In these or other embodiments, desulfurization can also be accomplished in the furnace or downstream of the furnace by reacting metal sulfides with H (in a reducing gas) to form metal and hydrogen sulfide (HS).

[0445] Other types of furnaces can use other chemical reactions. It will be understood that in chemical conversions of metal oxides to metals using carbon or reducing gases in the conversion, the carbon can be renewable carbon. The present disclosure provides renewable carbon in bio-derived reagents produced by pyrolysis of biomass. In certain embodiments, a portion of the carbon utilized in the furnace is not renewable carbon. In various embodiments, the percentage of renewable carbon of the total carbon consumed in a metal ore furnace can be at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100%.

[0446] In some variations of the present disclosure, a Tecnored furnace or a modified version thereof is utilized. The Tecnored process, originally developed by Tecnored Desenvolvimento Tecnologico SA in Brazil, is based on a low-pressure moving-bed reduction furnace that reduces cold-bonded, carbon-containing, self-bonded, and self-reduced pellets. Reduction occurs in a low-height shaft furnace at the reduction temperature. The process produces high-temperature metal (e.g., molten iron) with high efficiency.

[0447] Tecnored technology was developed as a cokeless steelmaking process, avoiding the investment and operation of environmentally harmful coke ovens and significantly reducing greenhouse gas emissions during hot metal production. The Tecnored process uses a combination of hot and cold blast and does not require additional oxygen. This eliminates the need for coke plants, sinter plants, and oxygen plants. Therefore, the process has significantly lower operating and investment costs than traditional steelmaking methods.

[0448] The Tecnored process can be adapted for use in a variety of ways. Some embodiments provide cold-bonded, self-reducing agglomerates (e.g., pellets or briquettes) made from iron ore fines or iron-bearing residues and bio-based reagents. These materials, mixed with fluxes and binders, are agglomerated and heat-set to produce briquettes / pellets with sufficient strength to meet the physical and metallurgical requirements of the Tecnored process. The resulting agglomerates are then refined in a Tecnored furnace. The fuel for the Tecnored furnace itself can be a high-carbon, bio-based reagent.

[0449] By combining fine particles of iron oxide with a reducing agent within the briquette, both the surface area of ​​the oxide in contact with the reducing agent and, consequently, the reaction rate, are dramatically increased. Self-reducing briquettes can be designed to contain sufficient reducing agent to allow the contained iron-bearing raw material, optionally with a flux, to be fully reduced to provide the desired slag chemistry. The self-reducing briquettes are hardened at low temperatures before being fed into the furnace. The heat required to drive the reaction within the self-reducing briquettes is provided by a bed of solid fuel, which may also be in the form of briquettes, onto which the self-reducing briquettes are fed into the furnace.

[0450] The Tecnored furnace has three zones: (i) the upper shaft zone, (ii) the melting zone, and (iii) the lower shaft zone. In the upper shaft zone, a solid fuel (e.g., a bio-based reagent) is charged. In this zone, the Boudouard reaction (C + CO2 → 2CO) is prevented, which saves energy. Post-combustion in this zone of the furnace burns the CO, which provides energy for preheating and charge reduction. Inside the pellets, the following reactions occur at a very fast rate:

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[0451] In the melting zone, reoxidation is prevented by a reducing atmosphere within the charge. Melting of the charge occurs under a reducing atmosphere. In the lower shaft zone, solid fuel is charged. The solid fuel can contain or consist essentially of high-carbon bio-based reagents. In this zone, further reduction of residual iron oxides and slagging reactions between gangue materials and fuel ash occur in the liquid state. Superheating of metal and slag droplets also occurs. These superheated metal and slag droplets sink by gravity to the hearth and accumulate there.

[0452] The improved Tecnored process employs two different inputs of carbon units: a reducing agent and a solid fuel. While the reducing agent is traditionally coal fines, in this disclosure the reducing agent can include a bio-based reagent in the form of carbon fines. The bio-based reagent is added to the mixture to produce self-reducing aggregates (pellets or briquettes). The amount of carbon fines required is determined by the C / F (carbon to ore fines) ratio, which can be selected to completely reduce the metal oxides.

[0453] The solid fuel (biogenic reagent) does not need to be in the form of a fine powder. For example, the solid fuel can be in chunks, approximately 40-80 mm in size, to meet the physical and thermal needs of the Tecnored process. The solid fuel is loaded through a side feeder (to avoid the endothermic Boudouard reaction in the upper shaft) and provides most of the energy required for the process. This energy is generated by the primary blast, which follows the reaction C + O → CO, and the secondary blast, which follows the reaction 2CO + O → CO, where CO is generated upstream by gasification of the solid fuel in the hearth.

[0454] In certain exemplary embodiments, the improved Tecnored process involves pelletizing iron ore fines up to about 140 mesh in size, biogenic reagent fines up to about 200 mesh in size, and flux, such as hydrated lime, up to about 140 mesh in size, using cement as a binder. The pellets are cured and dried at 200°C before being fed to the top of the Tecnored furnace. The total residence time of the charge in the furnace is about 30 to 40 minutes. Biogenic reagent, in the form of solid fuel 40 mm to 80 mm in size, is fed into the furnace below the hot pellet zone using a side feeder. Hot air, approximately 1150°C, is blown through tuyeres on the side of the furnace to provide combustion air for the biogenic carbon. A small amount of furnace gas flows through the side feeder, allowing it to be used for drying and preheating the solid fuel. Cooler blast air is blown in at a higher level to promote secondary combustion of CO in the upper shaft. The hot metal produced is poured into a ladle on a ladle car, which can tilt the ladle for slag removal. The molten iron is optionally desulfurized in the ladle, and the slag is scraped into a slag pot. The hot metal can contain about 3-5 wt% carbon.

[0455] Traditionally, external CO or H2 does not play a significant role in the autoreduction process using a Tecnored furnace. However, in the context of this disclosure, external H2 or CO (from the reducing gas) plays a significant role in the above reaction (Fe x O y +yCO→xFe+yCO2) or a reaction with hydrogen as a reactant (Fe x O y The overall chemical reaction can be assisted by increasing the rate or conversion of iron oxidation in the process (xFe + yH → xFe + yH O). The reduction chemical reaction can be assisted at least at the surface of the pellet or briquette, and possibly within the bulk phase of the pellet or briquette due to the fast mass transfer of the hot reducing gas. Some embodiments of the present disclosure combine aspects of a blast furnace with aspects of a Tecnored furnace, such that self-reducing pellets or briquettes are utilized in addition to the use of reducing gas in the furnace.

[0456] As previously mentioned, there are many possible furnace configurations for metal ore processing. While this specification does not detail the various conditions and chemical reactions that may occur in every possible furnace, those skilled in the art will understand that the principles of the present disclosure can be applied to essentially any furnace or process that uses carbon anywhere in the process for producing metals from metal ores.

[0457] It will also be observed that some processes utilize solid carbon, some utilize a reducing gas, and some utilize both solid carbon and a reducing gas. The processes provided herein produce both solid carbon (biogenic reagent) and a reducing gas. In some embodiments, only the solid biobased reagent is used in the metal ore conversion process. In other embodiments, only the reducing gas is used in the metal ore conversion process. In still other embodiments, both the solid biobased reagent and a reducing gas are used in the metal ore conversion process. In those embodiments using both renewable carbon sources, the percentage of the total carbon usage in the metal ore conversion from the reducing gas can be about, at least about, or up to about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100%. The remaining carbon usage can be derived from the biogenic reagent. Alternatively, some or all of the remaining carbon usage can be derived from traditional carbon inputs such as coal fines.

[0458] Pyrolysis Processes and Systems Suitable processes and systems for pyrolyzing biomass feedstocks and thereby producing carbonaceous biologically derived reagents are described in further detail below. Such processes and systems may be co-located with metal ore mining or processing sites, although the present disclosure is not limited to such co-location.

[0459] "Pyrolysis" and "pyrolyzing" generally refer to the thermal decomposition of a carbonaceous material. In pyrolysis, less oxygen is present than is required for complete combustion of the material, such as up to about 10%, 5%, 1%, 0.5%, 0.1%, or 0.01% of the amount of oxygen (on an O2 molar basis) required for complete combustion. In some embodiments, pyrolysis is carried out in the absence of oxygen.

[0460] Exemplary changes that can occur during pyrolysis include any of the following: (i) heat transfer from the heat source increases the temperature inside the feedstock; (ii) primary pyrolysis reactions begin at this high temperature, liberating volatiles and forming char; (iii) the hot volatiles flow toward the cooler solids, resulting in heat transfer between the hot volatiles and the cooler, unpyrolyzed feedstock; (iv) some of the volatiles in the cooler portions of the feedstock condense, followed by secondary reactions to produce tar; (v) the primary pyrolysis reactions occur simultaneously while autocatalytic secondary pyrolysis reactions proceed; and (vi) further pyrolysis, reforming, water-gas shift reactions, free radical recombination, or dehydration reactions can also occur, as a function of residence time, temperature, and pressure profiles.

[0461] Pyrolysis can at least partially dewater the starting material (e.g., lignocellulosic biomass). In various embodiments, pyrolysis removes at least about 50%, 75%, 90%, 95%, 99%, or more of the moisture from the starting material.

[0462] In some embodiments, multiple reactor zones are designed and operated to optimize pyrolysis carbon yield and product quality while maintaining flexibility and adjustability to feedstock variations and product requirements.

[0463] In some non-limiting embodiments, temperatures and residence times can be selected to achieve a relatively gentle pyrolysis chemistry. An advantage is that potentially, cell walls within the biomass structure can be substantially preserved, meaning that the final product can retain some, most, or all of the shape and strength of the biomass. To maximize this potential advantage, equipment that does not mechanically disrupt cell walls or otherwise convert biomass particles into small particulates can be utilized. Specific reactor configurations are described in accordance with the process description below.

[0464] Additionally, if the feedstock is a ground or sized feedstock, such as wood chips or pellets, it is desirable to carefully ground or sized the feedstock. Careful initial processing maintains the strength and cell wall integrity present in the natural feedstock source (e.g., trees). This is also important if the final product is to retain some, most, or all of the shape and strength of the biomass.

[0465] In some embodiments, the first zone of the pyrolysis reactor is configured to feed biomass (or another carbon-containing feedstock) in a manner that does not "shock" the biomass, which would rupture cell walls and initiate rapid decomposition of the solid phase into vapors and gases. This first zone can be thought of as mild pyrolysis.

[0466] In some embodiments, the second zone of the pyrolysis reactor is configured as a primary reaction zone where preheated biomass undergoes pyrolysis chemical reactions to release gases and condensable vapors, leaving behind a significant amount of solids that are high-carbon reaction intermediates. Biomass components (primarily cellulose, hemicellulose, and lignin) are decomposed to produce steam, which is released either by permeation through pores or by the formation of new nanopores. The latter effect contributes to increased porosity and surface area.

[0467] In some embodiments, a third zone of the pyrolysis reactor is configured to receive the carbon-rich reaction intermediates and provide some cooling of the solids. The third zone can be at a lower temperature than the second zone. In the third zone, chemical reactions and mass transport can be surprisingly complex. Without being limited to a particular theory or proposed mechanism, it is believed that secondary reactions can occur in the third zone. Essentially, carbon-containing components in the gas phase can be decomposed to form additional fixed carbon or adsorbed onto carbon. Thus, the final carbonaceous material can include not only the solid residue from the devolatilization step, but also additional carbon precipitated from the gas phase, such as by decomposition of organic vapors (e.g., tar) that can form carbon.

[0468] Certain embodiments extend the concept of additional carbon formation by including a separate unit that exposes the cooled carbon to an environment containing carbon-containing species to increase the carbon content of the final product. If the temperature of this unit is below the pyrolysis temperature, the additional carbon is expected to be in the form of adsorbed carbonaceous species rather than additional fixed carbon.

[0469] There are numerous options, such as intermediate input and output (purge or probe) flows of one or more phases present in any particular zone, various mass and energy recycling schemes, various additives that can be introduced anywhere in the process, and the ability to adjust process conditions, including both reaction and separation conditions, to tailor product distribution. Zone-specific input and output flows allow for better process monitoring and control, such as by FTIR sampling and dynamic process adjustments.

[0470] In some embodiments, no fast pyrolysis is used, and in some embodiments, no slow pyrolysis is used.Surprisingly high quality carbon materials, including compositions with very high fixed carbon fractions, can be obtained from the disclosed processes and systems.

[0471] In some embodiments, the pyrolysis process for producing high carbon bio-derived reagents comprises: (a) providing a carbon-containing feedstock comprising biomass; (b) optionally drying the raw material to remove moisture contained within the raw material; (c) optionally degassing the feedstock to remove interstitial oxygen, if any, contained in the feedstock; (d) pyrolyzing the feedstock in the presence of a substantially inert gas phase for at least 10 minutes at a temperature selected from about 250°C to about 700°C, thereby producing a high temperature pyrolysis solid, a condensable vapor, and a non-condensable gas; (e) separating condensable vapors and non-condensable gases from the hot pyrolysis solids; (f) cooling the hot pyrolysis solid, thereby producing a cooled pyrolysis solid; (g) recovering the carbon-rich biogenic reagent containing cooled pyrolysis solids.

[0472] For purposes of this disclosure, "biomass" shall be construed as any biological material or a mixture of biological and non-biological materials. Biomass elementally contains at least carbon, hydrogen, and oxygen. The methods and apparatus of the present disclosure can accommodate a wide range of materials of various types, sizes, and moisture contents.

[0473] Biomass includes, for example, plants and plant-derived materials, vegetation, agricultural waste, forestry waste, wood waste, paper waste, animal waste, poultry waste, and municipal solid waste. In various embodiments of the present disclosure utilizing biomass, the biomass feedstock can include one or more materials selected from wood harvesting residues, softwood chips, hardwood chips, tree branches, tree stumps, knots, leaves, bark, sawdust, off-spec paper pulp, cellulose, corn, corn stover, wheat straw, rice straw, sugarcane bagasse, switchgrass, miscanthus, animal manure, municipal solid waste, municipal sewage, commercial waste, grape pumice, almond shells, pecan shells, coconut shells, coffee grounds, grass pellets, hay pellets, wood pellets, cardboard, paper, carbohydrates, plastics, and textiles. One skilled in the art will readily appreciate that the options for feedstock are virtually limitless.

[0474] The present disclosure can also be used with mixtures of biomass and fossil fuels (e.g., biomass / coal mixtures). In some embodiments, the carbon-containing feedstock includes coal, oil shale, crude oil, asphalt, or solids from crude oil processing (e.g., pet coke). The feedstock can include scrap tires, recycled plastic, recycled paper, construction waste, demolition waste, and other waste or recycled materials. The carbon-containing feedstock can be transported by any known means, such as truck, train, ship, barge, tractor-trailer, or other vehicle or transportation means.

[0475] The selection of a particular raw material is generally made in a manner that favors an economical process. Regardless of the raw material selected, it can be screened to remove undesired materials. The raw material can optionally be dried before processing.

[0476] The raw materials used can be provided or processed into various particle sizes or shapes. For example, the feed material can be a fine powder or a mixture of fine and coarse particles. The feed material can also be in the form of larger pieces of material, such as wood chips or other forms of wood (e.g., round, cylindrical, square, etc.). In some embodiments, the feed material comprises particles in pellets or other agglomerated forms that are processed together or otherwise bound by a binder or the like.

[0477] It is noted that size reduction is a costly and energy-intensive process. Pyrolyzed materials can be sized with significantly less energy input, meaning that it may be preferable to reduce the particle size of the product rather than the feedstock. This is an option in the present disclosure because the process does not require fine starting material and does not necessarily require significant particle size reduction during processing. The ability to process very large feedstock pieces is an important economic advantage of the present disclosure. It is noted that some market applications of high-carbon products actually require large sizes (e.g., centimeters) so that large pieces can be sourced, produced, and sold in some embodiments.

[0478] If it is desired to produce a final carbonaceous biogenic reagent with structural integrity, such as a cylindrical morphology, there are at least two options in the context of this disclosure. First, the material produced in the process can be collected and then further mechanically processed into the desired shape. For example, the product can be pressed or pelletized using a binder. The second option is to utilize a feedstock that generally processes the final product into the desired size or shape, and employ processing steps that do not destroy the basic structure of the feedstock. In some embodiments, the feedstock and the product have similar geometric shapes, such as a sphere, cylinder, or cube.

[0479] The ability to maintain the approximate size of the feed material throughout the process is beneficial when product strength is important, and it avoids the difficulty and cost of pelletizing high fixed carbon materials.

[0480] As will be appreciated, the starting feedstock can be provided at a range of moisture levels. In some embodiments, the feedstock can already be sufficiently dry without the need for further drying prior to pyrolysis. Typically, it is desirable to utilize commercially available biomass sources that have moisture and to provide the biomass through a drying step before introducing it into the pyrolysis reactor. However, in some embodiments, dry feedstock can be utilized.

[0481] It is desirable to provide a relatively low-oxygen environment in the pyrolysis reactor, such as about or at most about 10 mol%, 5 mol%, 4 mol%, 3 mol%, 2 mol%, 1.5 mol%, 1 mol%, 0.5 mol%, 0.2 mol%, 0.1 mol%, 0.05 mol%, 0.02 mol%, or 0.01 mol% O in the gas phase. First, for safety reasons, uncontrolled combustion should be avoided in the pyrolysis reactor. Some total carbon oxidation to CO can occur, and the heat released from the exothermic oxidation can support the endothermic pyrolysis reaction. Extensive carbon oxidation, including partial oxidation to syngas, reduces carbon yield to solids.

[0482] In particular, it is difficult to achieve a completely oxygen-free environment in the reactor. This limit can be approached, and in some embodiments, the reactor is substantially free of molecular oxygen in the gas phase. To ensure that little or no oxygen is present in the pyrolysis reactor, it is desirable to remove air from the feed before it is introduced into the reactor. There are various methods for removing or reducing air in the feed.

[0483] In some embodiments, a degassing unit is utilized in which the feedstock, before or after drying, is conveyed in the presence of another gas that can remove adsorbed oxygen and penetrate the pores of the feedstock to remove oxygen from the pores. Essentially, any gas with less than 21 vol% O2 can be used with varying effectiveness. In some embodiments, nitrogen is used. In some embodiments, CO or CO2 is used. Mixtures can be used, such as a mixture of nitrogen and a small amount of oxygen. Although adding large amounts of moisture back to the feedstock should be avoided, water vapor can be present in the degassed gas. The effluent from the degassing unit can be purged (to the atmosphere or to an effluent treatment device) or recycled.

[0484] In principle, the effluent from the degassing unit (or a portion thereof) could be introduced into the pyrolysis reactor itself, since the oxygen removed from the solids is now highly diluted. In this embodiment, it may also be advantageous to introduce the degassed effluent gas into the final zone of the reactor if the reactor is operated in a countercurrent configuration.

[0485] Various types of degassing units can be used. Drying can be performed with subsequent degassing, as drying is less efficient at removing soluble oxygen from the moisture present. In certain embodiments, the drying and degassing steps are combined in a single unit, or some degassing is achieved during drying, etc.

[0486] The optionally dried and optionally degassed feedstock is introduced into a pyrolysis reactor or multiple reactors arranged in series or parallel. The feedstock can be introduced using any known means, including, for example, a screw feeder or a lock hopper. In some embodiments, the material feed system incorporates an air knife.

[0487] When a single pyrolysis reactor is used, there can be multiple zones, e.g., two, three, four or more zones, which can individually control temperature, solids residence time, gas residence time, gas composition, flow pattern or pressure to tailor overall process performance.

[0488] References to "zones" shall be interpreted broadly to include regions of space within a single physical unit, physically separate units, or any combination thereof. In the case of continuous reactors, the division of zones can be related to structure, such as the presence of vanes within the reactor, or the presence of separate heating elements to provide heat to distinct zones. Alternatively or additionally, the division of zones in a continuous reactor can be related to functions such as different temperatures, fluid flow patterns, solids flow patterns, and extent of reaction. In the case of single batch reactors, a "zone" is an operating region in time, not space. Multiple batch reactors can also be used.

[0489] It will be understood that an abrupt transition from one zone to another is not required. For example, the boundary between the preheating zone and the pyrolysis zone can be somewhat arbitrary; some pyrolysis can occur in a portion of the preheating zone, while some "preheating" continues to occur in the pyrolysis zone. The temperature profile within the reactor can also be continuous, including the zone boundaries within the reactor.

[0490] Some embodiments employ a first zone operating under preheat or mild pyrolysis conditions. The temperature of the first zone can be selected from about 150° C. to about 500° C., e.g., about 300° C. to about 400° C. The temperature of the first zone should not be so high as to shock the biomass material, which would rupture the cell walls and initiate rapid decomposition of the solid phase into vapors and gases.

[0491] All references to zone temperatures in this specification should be interpreted non-limitingly to include temperatures applicable to the bulk solids present, the gas phase, or the reactor wall (on the process side). It will be understood that each zone will have temperature gradients both axially and radially, as well as over time (i.e., after start-up or due to transients). Thus, references to zone temperatures can refer to references to average temperatures or other effective temperatures that can affect the actual reaction rate. Temperatures can be measured directly by thermocouples or other temperature probes, or indirectly measured or estimated by other means.

[0492] The second zone, or generally the primary pyrolysis zone, operates under pyrolysis or carbonization conditions. The temperature of the second zone can be selected from about 250°C to about 700°C, such as about, at least about, or up to about 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, or 650°C. Within this zone, the preheated biomass undergoes pyrolysis chemical reactions, releasing gases and condensable vapors, leaving behind a large amount of solid material as a high-carbon reaction intermediate. Biomass components (primarily cellulose, hemicellulose, and lignin) are decomposed to produce steam, which is released by permeating pores or by forming new pores. The preferred temperature depends, at least, on the residence time in the second zone, as well as the nature of the feedstock and the desired product characteristics.

[0493] The third zone, or cooling zone, operates to cool the carbon-rich reaction intermediate to various degrees. At a minimum, the temperature of the third zone should be lower than the temperature of the second zone. The temperature of the third zone can be selected from about 100°C to about 550°C, for example, from about 150°C to about 350°C.

[0494] Chemical reactions continue to occur in the cooling zone. Without being limited to a particular theory, it is believed that secondary pyrolysis reactions begin in the third zone. Carbon-containing components in the gas phase can condense (as the temperature in the third zone is reduced). However, the temperature remains high enough to promote reactions that can form additional fixed carbon from the condensed liquid (secondary pyrolysis), or at least reactions that can form bonds between adsorbed species and fixed carbon. One exemplary reaction that can occur is the Boudouard reaction, which converts carbon monoxide to carbon dioxide and fixed carbon.

[0495] The residence time of a reactor zone can vary. Time and temperature interact, such that for a desired amount of pyrolysis, higher temperatures allow for shorter reaction times, and vice versa. In a continuous reactor (zone), the residence time is the volume divided by the volumetric flow rate. In a batch reactor, the residence time is the batch reaction time after heating to the reaction temperature.

[0496] It should be recognized that in a multiphase reactor, multiple residence times exist. In the present context, there are both solid and vapor phase residence times (and residence time distributions) in each zone. In a given apparatus using multiple zones and with a given throughput, the residence times between zones are generally associated with the solid phase side, but residence times may not be associated with the vapor phase side if multiple inlet and outlet ports are used in the individual zones. Solid residence times and vapor residence times are not associated.

[0497] The solids residence time in the preheat zone can be selected from about 5 minutes to about 60 minutes, for example, about 10, 20, 30, 40, or 50 minutes. Depending on the temperature, sufficient time is desired to allow the biomass to reach the desired preheat temperature. Heat transfer rates, which depend on particle type and size, physical equipment, and heating parameters, indicate the minimum residence time necessary to allow the solids to reach the desired preheat temperature. Unless a moderate pyrolysis is intended in the preheat zone, additional time is generally undesirable because it contributes to higher capital costs.

[0498] The solids residence time in the pyrolysis zone can be selected from about 10 minutes to about 120 minutes, e.g., about 20, 30, 40, 50, 60, 70, 80, 90, or 100 minutes. Depending on the pyrolysis temperature in this zone, there should be sufficient time to allow the carbonization chemical reaction to occur after the necessary heat transfer. To remove a significant amount of non-carbon elements in a time of less than about 10 minutes, the temperature needs to be very high, e.g., above 700°C. This temperature promotes rapid pyrolysis and the evolution of steam and gases from the carbon itself, which should be avoided if the desired product is solid carbon.

[0499] In static systems, there is an equilibrium transformation that is essentially reached at some point. When, as in certain embodiments, steam flows continuously over the solids while volatiles are continuously removed, the equilibrium constraint can be lifted, allowing pyrolysis and devolatilization to continue until the reaction rate approaches zero. Longer times do not tend to significantly alter the remaining refractory solids.

[0500] The residence time of the solids in the cooling zone can be selected from about 5 minutes to about 60 minutes, for example, about 10, 20, 30, 40, or 50 minutes. Depending on the cooling temperature in this zone, there should be sufficient time to allow the carbon solids to cool to the desired temperature. The cooling rate and temperature will dictate the minimum residence time required to allow the carbon to cool. Unless some degree of secondary pyrolysis is desired, additional time is generally not desired.

[0501] As described above, the vapor phase residence times can be individually selected and controlled. The vapor residence time in the preheating zone can be selected from about 0.1 minutes to about 15 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. The vapor residence time in the pyrolysis zone can be selected from about 0.1 minutes to about 20 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes. The vapor residence time in the cooling zone can be selected from about 0.1 minutes to about 15 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. A short vapor residence time promotes rapid evacuation of volatile materials from the system, while a long vapor residence time promotes reaction between components in the vapor phase and components in the solid phase.

[0502] The mode of operation of the reactor and the overall system can be continuous, semi-continuous, batch, or any combination or variation thereof. In some embodiments, the reactor is a continuous countercurrent reactor in which solids and vapor flow in substantially opposite directions. The reactor can also be operated in batch mode, but operation is performed in simulated vapor countercurrent, for example, by periodically introducing and removing the vapor phase from the batch vessel.

[0503] A variety of flow patterns can be desired or observed. While chemical reactions and simultaneous separations involve multiple phases in multiple reactor zones, fluid dynamics can become very complex. Solids flow can approach plug flow (well mixed radially), while vapor flow can approach perfectly mixed flow (high velocity transport in both radial and axial directions). Multiple inlet and outlet ports for vapor can contribute to overall mixing.

[0504] The pressure of each zone can be individually selected and controlled. The pressure of each zone can be independently selected from about 1 kPa to about 3000 kPa, for example, about 101.3 kPa (standard atmospheric pressure). Independent zone pressure control of pressure is possible when using multiple gas inlets and outlets, including vacuum ports for venting gases when subatmospheric zone pressures are desired.

[0505] In some embodiments, the present process can be conveniently operated at atmospheric pressure. There are many advantages associated with operating at atmospheric pressure, from mechanical simplicity to improved safety. In certain embodiments, the pyrolysis zone operates at a pressure of about 90 kPa, 95 kPa, 100 kPa, 101 kPa, 102 kPa, 105 kPa, or 110 kPa (absolute).

[0506] Vacuum operation (e.g., 10-100 kPa) helps remove volatiles from the system quickly. Higher pressures (e.g., 100-1000 kPa) can be useful when feeding off-gas to high-pressure operation. High pressures can also be useful to promote heat transfer, chemical reactions, or separations.

[0507] The step of separating the condensable vapors and non-condensable gases from the hot pyrolysis solids can be performed in the reactor itself or using a separate separation unit. A substantially inert sweep gas can be introduced into one or more of the zones. The condensable vapors and non-condensable gases are then removed from the zone(s) in the sweep gas and discharged out of the reactor.

[0508] The sweep gas can be, for example, N, Ar, CO, CO, H, H0, CH, other light hydrocarbons, or combinations thereof. The sweep gas can first be preheated before introduction or possibly cooled if obtained from a heating source.

[0509] A sweep gas removes volatile components more thoroughly by removing them from the system before they condense or further react. A sweep gas allows volatile components to be removed at a higher rate than simple volatilization at a given process temperature. The use of a sweep gas also allows for milder temperatures to be used to remove a given amount of volatile component. The reason a sweep gas improves volatile component removal is that the mechanism of separation is liquid / gas separation by the sweep gas, rather than simply relative volatility. A sweep gas can reduce the mass transfer limitation of volatilization as well as the thermodynamic limitation by continually reducing a given volatile component, causing more volatile components to volatilize and reach thermodynamic equilibrium.

[0510] Some embodiments remove gases rich in volatile organic carbon from subsequent processing stages to produce products with a high fixed carbon content. Otherwise, the volatile carbon can be adsorbed or absorbed into the pyrolysis solids, requiring additional energy (cost) to obtain the pure carbon that may be desired. Rapid removal of vapors is believed to increase porosity in the pyrolysis solids. For some products, higher porosity is desirable.

[0511] In certain embodiments, the sweep gas in combination with a relatively low process pressure, such as atmospheric pressure, quickly removes vapors without requiring large amounts of inert gas.

[0512] In some embodiments, the sweep gas flows countercurrently to the feed flow direction. In other embodiments, the sweep gas flows cocurrently to the feed flow direction. In some embodiments, the flow pattern of the solids approaches plug flow, while the flow patterns of the sweep gas and vapor phase generally approach perfectly mixed flow in one or more zones.

[0513] A sweep can be performed in any one or more of the reactor zones. In some embodiments, a sweep gas is introduced into the cooling zone and extracted (along with generated volatiles) from the cooling zone or the pyrolysis zone. In some embodiments, a sweep gas is introduced into the pyrolysis zone and extracted from the pyrolysis zone or the preheating zone. In some embodiments, a sweep gas is introduced into the preheating zone and extracted from the pyrolysis zone. In these or other embodiments, a sweep gas is introduced into and extracted from each of the preheating zone, pyrolysis zone, and cooling zone.

[0514] In some embodiments, the zone in which the separation occurs is a physically separate unit from the reactor. Separation units or zones can be located between reactor zones, if desired. For example, a separation unit can be located between a pyrolysis unit and a cooling unit.

[0515] The sweep gas can be introduced continuously, especially if the solids flow is continuous. If the pyrolysis reaction is operated as a batch process, the sweep gas can be introduced after a certain time or periodically to remove volatiles. Even if the pyrolysis reaction is operated continuously, the sweep gas can be introduced semi-continuously or periodically, if desired, using appropriate valves and controls.

[0516] The volatile-containing sweep gas can be discharged from one or more reactor zones or can be combined if obtained from multiple zones. The resulting gas stream containing various vapors can then be fed to a thermal oxidizer to control atmospheric emissions. Any known thermal oxidation unit can be used. In some embodiments, natural gas and air are fed to the thermal oxidizer to reach a temperature sufficient to substantially destroy the volatiles contained therein.

[0517] The thermal oxidizer effluent is a hot gas stream containing water, carbon dioxide, and nitrogen. If desired, this effluent stream can be vented directly to the atmosphere. The energy content of the thermal oxidizer effluent can be recovered, such as in a waste heat recovery unit. The energy content can also be recovered by heat exchange with another stream (e.g., sweep gas). The energy content can be utilized to directly or indirectly heat or assist in heating units anywhere in the process, such as a dryer or reactor. In some embodiments, essentially all of the thermal oxidizer effluent is used to indirectly heat (utility side) the dryer. The thermal oxidizer can use fuels other than natural gas.

[0518] The yield of carbonaceous material can vary depending on the aforementioned factors, including the type of feedstock and process conditions. In some embodiments, the net yield of solids as a percentage of the starting material, on a dry basis, is at least 25%, 30%, 35%, 40%, 45%, 50%, or more. The remainder is divided into condensable vapors, such as terpenes, tars, alcohols, acids, aldehydes, or ketones, and non-condensable gases, such as carbon monoxide, hydrogen, carbon dioxide, or methane. The relative amount of condensable vapors compared to non-condensable gases also depends on process conditions, including the presence of moisture.

[0519] In terms of carbon balance, in some embodiments, the net yield of carbon as a percentage of the starting carbon in the feedstock is at least 25%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, or more. For example, in some embodiments, the carbonaceous material comprises about 40% to about 70% of the carbon contained in the starting feedstock. The remaining carbon produces methane, carbon monoxide, carbon dioxide, light hydrocarbons, aromatics, tars, terpenes, alcohols, acids, aldehydes, or ketones to varying degrees.

[0520] In some embodiments, these compounds, or portions thereof, are mixed with carbon-rich bodies to increase the carbon and energy content of the product. In these embodiments, some or all of the resulting gas stream from the reactor, containing various vapors, can be at least partially condensed and then passed over cooled pyrolysis solids obtained from a cooling zone or a separate cooling unit. These embodiments are described in more detail below.

[0521] After reaction and cooling in the cooling zone (if present), the carbonaceous solids can be introduced into a different cooling unit. In some embodiments, the solids are collected and simply cooled at a slow rate. If the carbonaceous solids are reactive or unstable in air, it may be desirable to maintain an inert atmosphere or to rapidly cool the solids, for example to a temperature below 40° C., e.g., room temperature. In some embodiments, water cooling is used for rapid cooling. In some embodiments, a fluidized bed cooler is used. The term "cooling unit" should be broadly construed to include vessels, tanks, pipes, or portions thereof.

[0522] In some embodiments, the process further includes operating a cooling unit to cool the warm pyrolysis solids with steam, thereby producing cold pyrolysis solids and superheated steam, and drying is performed at least in part using the superheated steam obtained from the cooling unit. Optionally, the cooling unit can be operated to first cool the warm pyrolysis solids with steam to a first cooling unit temperature and then with air to a second cooling unit temperature, the second cooling unit temperature being lower than the first cooling unit temperature and associated with a reduced risk of combustion of the warm pyrolysis solids in the presence of air.

[0523] After cooling to ambient temperature, the carbonaceous solids can be collected and stored, transported to another site, shipped to another site, or otherwise disposed of, traded, or sold. The solids can be fed to a unit for particle size reduction. A variety of size reduction units are known in the art, including crushers, shredders, grinders, pulverizers, jet mills, pin mills, and ball mills.

[0524] Screening or some other means for separating based on particle size may be included. Grinding, if present, may occur upstream or downstream of the grinding. A portion of the screened material (e.g., large chunks) may be returned to the grinding unit. Small and large particles may be recovered for separate downstream applications. In some embodiments, the cooled pyrolysis solids are ground into a fine powder, e.g., ground carbon or activated carbon product.

[0525] Various additives can be introduced throughout the process, before, during, or after any step disclosed herein. Additives can be broadly categorized into process additives selected to improve process performance, such as carbon yield or pyrolysis time / temperature to achieve a desired carbon purity, and product additives selected to improve one or more properties of the high-carbon bio-based reagent or downstream products containing the reagent. Certain additives can improve the properties of the process and the product (biologically based reagent or product containing the bio-based reagent).

[0526] Additives can be added before, during, or after any one or more steps of the process, including addition to the feedstock itself at any time before or after harvest. Additive treatment can be incorporated before, during, or after sizing, drying, or other preparation of the feedstock. Additives can be incorporated at or on feedstock supply facilities, transport trucks, unloading equipment, storage containers, conveyors (including open or closed conveyors), dryers, process heaters, or other units. Additives can be added anywhere in the pyrolysis process itself, using appropriate means for introducing the additive. Additives can be added after carbonization or after comminution, if desired.

[0527] In some embodiments, the additive is selected from a metal, a metal oxide, a metal hydroxide, or a combination thereof. For example, the additive can be selected from, but is not limited to, magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorspar, bentonite, calcium oxide, lime, and combinations thereof.

[0528] In some embodiments, the additive is selected from an acid, a base, or a salt thereof, for example, but not limited to, sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, or a combination thereof.

[0529] In some embodiments, the additive is selected from metal halides. Metal halides are compounds between metals and halogens (fluorine, chlorine, bromine, iodine, and astatine). Halogens can form many compounds with metals. Metal halides are generally obtained by direct reaction of a basic metal salt with a hydrohalic acid, or more commonly, by neutralization. In some embodiments, the additive is selected from iron chloride (FeCl2 or FeCl3), iron bromide (FeBr2 or FeBr3), or hydrates thereof, and any combination thereof.

[0530] The additives can result in a final product with a higher energy content (energy density). The increase in energy content can be achieved by increasing total carbon, fixed carbon, volatile carbon, or even hydrogen. Alternatively or additionally, the increase in energy content can be achieved by removing non-combustible materials or materials with a lower energy density than carbon. In some embodiments, the additives reduce the extent of liquid formation, promote solid and gas formation, or promote solid formation.

[0531] Without being limited to any particular hypothesis, the additives can chemically modify the biomass or treated biomass prior to pyrolysis to reduce cell wall fracture and increase strength / integrity. In some embodiments, the additives can increase the fixed carbon content of the biomass feedstock prior to pyrolysis.

[0532] Additives can result in bio-derived reagents with improved mechanical properties, such as yield strength, compressive strength, tensile strength, fatigue strength, impact strength, elastic modulus, bulk modulus, and shear modulus. Additives can improve mechanical properties by their mere presence (e.g., the additive itself imparts strength to the mixture) or by some change that occurs within the additive phase or the resulting mixture. For example, a reaction such as vitrification can occur within a portion of the bio-derived reagent containing the additive, thereby improving the final strength.

[0533] Chemical additives can be applied to wet or dry biomass feedstock. The additives can be applied as a solid powder, spray, mist, liquid, or vapor. In some embodiments, the additives can be introduced by spraying or immersing a liquid solution (e.g., aqueous solution or solvent) into a tank, vessel, bag, or other container.

[0534] In certain embodiments, a soaking pretreatment is used in which the solid feedstock is soaked in a bath containing the additive, either batchwise or continuously, for a time sufficient for the additive to penetrate the solid feedstock.

[0535] In some embodiments, additives added to the feedstock can reduce the energy required for pyrolysis or improve the yield of the carbonaceous product. In these or other embodiments, additives added to the feedstock can provide desirable functionality for the intended use of the carbonaceous product.

[0536] The throughput or process capacity can vary widely from small laboratory scale units to full operations, including any pilot, demonstration, or semi-commercial scale. In various embodiments, the process capacity (feedstock, product, or both) is at least about 1 kg / day, 10 kg / day, 100 kg / day, 1 ton / day (all tons are metric tons), 10 tons / day, 100 tons / day, 500 tons / day, 1000 tons / day, 2000 tons / day, or more.

[0537] In some embodiments, the solids produced, or a portion thereof, can be recycled to the front end of the process, i.e., to a drying or degassing unit, or directly to the reactor. By returning to the front end and passing through the process again, the treated solids can have a higher fixed carbon content. The solids, liquids, and gas streams produced or present in the process can be independently recycled, passed to subsequent steps, or removed / purged from the process at any point.

[0538] In some embodiments, the pyrolysis material is recovered and then fed to a separate unit for further pyrolysis to produce a product with higher carbon purity. In some embodiments, secondary processing can occur in a simple container, such as a steel drum, through which a heated inert gas (e.g., heated N2) is passed. Other containers useful for this purpose include process tanks, barrels, bins, totes, sacks, and roll-offs. This secondary sweep gas containing volatiles can be sent, for example, to a thermal oxidizer or returned to the main process reactor. To cool the final product, for example, another inert gas stream, initially at ambient temperature, can be passed through the solids to cool them and then returned to the inert gas preheat system.

[0539] Some variations of the present disclosure utilize a high carbon biologically derived reagent production system, the system comprising: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operative communication with the feeder, the dryer configured to remove moisture contained in the carbon-containing feedstock; (c) a multi-zone reactor disposed in operative communication with the dryer, the multi-zone reactor including a pyrolysis zone disposed in operative communication with a spatially separated cooling zone, the multi-zone reactor configured with an outlet for removing condensable vapors and non-condensable gases from the solids; (d) a solid state cooler disposed in operable communication with the multi-zone reactor; (e) a carbon-rich biogenic reagent recovery unit disposed in operable communication with the solid-state cooler.

[0540] Some variations utilize a high carbon, biologically derived reagent production system, which comprises: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operative communication with the feeder, the dryer configured to remove moisture contained in the carbon-containing feedstock; (c) an optional preheater disposed in operable communication with the dryer configured to heat or gently pyrolyze the feedstock; (d) a pyrolysis reactor disposed in operative communication with the preheater, the pyrolysis reactor configured to pyrolyze the feedstock; (e) a cooler disposed in operative communication with the pyrolysis reactor configured to cool the pyrolysis solids; (f) a carbon-rich biological reagent recovery unit disposed in operable communication with the cooler; The system comprises a gas outlet for removing condensable vapors and non-condensable gases from the solids.

[0541] The feeder may be physically integrated with the multi-zone reactor, such as by using a screw feeder or auger mechanism to introduce feed solids into the first reaction zone.

[0542] In some embodiments, the system further includes a preheating zone disposed in operable communication with the pyrolysis zone. Each of the pyrolysis zone, cooling zone, and preheating zone (if present) can be disposed within a single unit, and can be disposed within separate units.

[0543] Optionally, the dryer can be configured as a drying zone within a multi-zone reactor. Optionally, the solids cooler can be located within the multi-zone reactor (i.e., configured as an additional cooling zone or integrated with the main cooling zone).

[0544] The system can include a purging means for removing oxygen from the system. For example, the purging means can include one or more inlets for introducing a substantially inert gas and one or more outlets for removing the substantially inert gas and displaced oxygen from the system. In some embodiments, the purging means is a degasser disposed in operative communication between the dryer and the multi-zone reactor.

[0545] The multi-zone reactor can be configured with at least a first gas inlet and a first gas outlet, which can be located in communication with different zones or the same zone.

[0546] In some embodiments, the multi-zone reactor is configured with a second gas inlet or a second gas outlet. In some embodiments, the multi-zone reactor is configured with a third gas inlet or a third gas outlet. In some embodiments, the multi-zone reactor is configured with a fourth gas inlet or a fourth gas outlet. In some embodiments, each zone present within the multi-zone reactor is configured with a gas inlet and a gas outlet.

[0547] The gas inlets and outlets not only allow for the introduction and exhaust of vapors, but the gas outlets (probes) in particular allow for accurate process monitoring and control over various stages of the process, and in some cases, over the entire process. Accurate process monitoring is expected to result in improved yields and efficiencies, both dynamically and over time, allowing for adjustments to process conditions using operating history.

[0548] In some embodiments, a reactive gas probe is placed in operative communication with the pyrolysis zone. Such a reactive gas probe can be useful for sampling and analyzing gases to determine the extent of reaction, pyrolysis selectivity, or other process monitoring. Based on the measurements, the process can then be controlled or adjusted in various ways, such as by adjusting feed rates, inert gas sweep rates, temperature (in one or more zones), pressure (in one or more zones), additives, etc.

[0549] As intended herein, "monitoring and controlling" via a reactive gas probe should be interpreted to include taking one or more samples via a reactive gas probe and, optionally, making process or equipment adjustments based on the measurements, if deemed necessary or desirable, using known process control principles (e.g., feedback, feedforward, proportional-integral-derivative logic, etc.).

[0550] The reactive gas probe can be configured to withdraw a gas sample in a variety of ways. For example, the sampling line can be at a pressure lower than the pressure of the pyrolysis reactor so that a certain amount of gas can be easily withdrawn from the pyrolysis zone when the sampling line is opened. The sampling line can be under vacuum, such as when the pyrolysis zone is near atmospheric pressure. The reactive gas probe can be associated with one gas output or a portion thereof (e.g., a line split off from the gas output line).

[0551] In some embodiments, both the gas input and gas output are utilized as reactive gas probes by periodically introducing inert gas into the zone and withdrawing the inert gas from the gas output along with a process sample (a "sample sweep"). Such an arrangement can be used in zones that do not have a gas inlet / outlet for the process's substantially inert gas, or the reactive gas probe can be associated with a separate gas inlet / outlet in addition to the process inlet and outlet. The sample inert gas periodically introduced and withdrawn for sampling (in embodiments utilizing a sample sweep) can be different from the process inert gas, if desired, either for analytical accuracy or for reasons of introducing an analytical tracer.

[0552] For example, the acetic acid concentration in the gas phase of the pyrolysis zone can be measured by extracting a sample using a gas probe and then analyzing it using an appropriate technique (gas chromatography (GC), mass spectrometry (MS), GC-MS, or Fourier transform infrared spectroscopy (FTIR)). For example, CO or CO2 concentration in the gas phase can be measured and used as an indicator of pyrolysis selectivity to gases / vapors. For example, terpene concentration in the gas phase can be measured and used as an indicator of pyrolysis selectivity to liquids.

[0553] In some embodiments, the system further includes at least one additional gas probe disposed in operative communication with the cooling zone, or the drying zone (if present) or the preheating zone (if present).

[0554] A gas probe for the cooling zone is useful, for example, to determine the extent of any additional chemical reactions occurring in the cooling zone. A gas probe in the cooling zone can also be useful as an independent measurement of temperature (e.g., in addition to a thermocouple located in the cooling zone). This independent measurement can be a correlation between cooling temperature and a measurement of a particular material. This correlation can be developed separately or can be established after a period of process operation.

[0555] A gas probe for the drying zone can be useful to determine the degree of drying, for example, by measuring the moisture content. A gas probe in the preheat zone can be useful, for example, to determine the degree of any mild pyrolysis that is occurring.

[0556] In certain embodiments, the cooling zone comprises a gas inlet and the pyrolysis zone comprises a gas outlet, thereby creating a substantially countercurrent flow of the gas phase relative to the solid phase. Alternatively or additionally, the preheating zone (if present) can comprise a gas outlet, thereby creating a substantially countercurrent flow of the gas phase relative to the solid phase. Alternatively or additionally, the drying zone can comprise a gas outlet, thereby creating a substantially countercurrent flow.

[0557] The pyrolysis reactor or reactors can be selected from any suitable reactor configuration capable of carrying out a pyrolysis process. Exemplary reactor configurations include, but are not limited to, a fixed bed reactor, a fluidized bed reactor, an entrained bed reactor, an auger, an ablation reactor, a rotating cone, a rotary drum kiln, a calciner, a roaster, a moving bed reactor, a transport bed reactor, an ablation reactor, a rotating cone, or a microwave-assisted pyrolysis reactor.

[0558] In some embodiments where an auger is used, sand or another heat carrier can optionally be used. For example, the feedstock and sand can be fed into one end of a screw. The screw mixes the sand and feedstock and transports them through the reactor. The screw can adequately control the feedstock residence time and not dilute the pyrolysis products with a carrier or fluidizing gas. The sand can be reheated in a separate vessel.

[0559] In some embodiments where an ablation process is used, the feedstock moves at high velocity against a hot metal surface. Ablation of any char formed on the surface can maintain a high heat transfer rate. Such an apparatus can prevent dilution of the product. Alternatively, the feedstock particles can be suspended in a carrier gas and introduced at high velocity through a cyclone with heated walls.

[0560] In some embodiments in which a fluidized bed reactor is used, the feedstock may be introduced into a bed of hot sand fluidized by a gas, which may be recycled product gas. References herein to "sand" also include similar substantially inert materials, such as glass particles and recovered ash particles. The high rate of heat transfer from the fluidized sand allows the feedstock to heat up rapidly. Friction with the sand particles may cause some abrasion. Heat is typically provided by heat exchange tubes through which hot combustion gases flow.

[0561] A circulating fluidized bed reactor can be used, with gas, sand, and feedstock moving together. Exemplary transport gases include recycled product gas and combustion gas. The high heat transfer rate from the sand ensures that the feedstock heats up quickly, resulting in stronger ablation than in a conventional fluidized bed. A separator can be used to separate the product gas from the sand and char particles. The sand particles can be reheated in a fluidized burner vessel and recycled to the reactor.

[0562] In some embodiments, the multi-zone reactor is a continuous reactor including a feedstock inlet, a plurality of spatially separated reaction zones configured for individual temperature control and mixing within each reaction zone, and a carbonaceous solids outlet, one of the reaction zones configured with a first gas inlet for introducing a substantially inert gas into the reactor, and one of the reaction zones configured with a first gas outlet.

[0563] In various embodiments, the reactor comprises at least two, three, four, or more reaction zones. Each of the reaction zones is disposed in communication with an individually adjustable heating means independently selected from electrical heat transfer, steam heat transfer, hot oil heat transfer, phase change heat transfer, waste heat transfer, or combinations thereof. In some embodiments, the reactor zones are heated by the effluent stream from the thermal oxidizer, if present. In some embodiments, at least one additional reactor zone is heated by the effluent stream from the thermal oxidizer, if present.

[0564] The reactor can be configured to independently a...

Claims

1. 1. A system for producing carbon-negative hydrogen, comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; (i) receiving the biocatalyst; (ii) optionally receiving a first portion of the biogas; and (iii) H ２ and a third heating vessel or heating zone in fluid communication with the second heating vessel or heating zone, the third heating vessel or heating zone being configured to produce CO. ２ a third heating vessel or heating zone, comprising means for recovering a thermal oxidizer configured to oxidize at least a portion of the biogas to generate heat, the thermal oxidizer being in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated, and H ２ 0 kg CO per metric ton ２ 1. A system capable of producing carbon-negative hydrogen characterized by a carbon intensity of less than e.

2. The third heating vessel or heating zone is configured to receive the first portion of the biogas, and the third heating vessel or heating zone is configured to convert a portion of the biogas into the H ２ and CO. The system of claim 1 , configured to convert CO.

3. 3. The system of claim 1, further comprising a separation unit configured to separate a second recovered water stream from the biogas.

4. The system of claim 3 , wherein the third heating vessel or heating zone comprises an inlet for receiving the second recovered water stream.

5. The system according to any one of claims 1 to 4, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are spatially arranged sequentially so that operation of the system can be performed continuously.

6. 6. The system of claim 1, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate in countercurrent flow with respect to a solid phase and a gas phase, respectively.

7. 7. The system of claim 1, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical solids downflow vessel.

8. The system of any one of claims 1 to 7, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone each comprise an internal vessel lining.

9. The system includes: ２ or a fourth heating vessel or heating zone configured to use the CO to reduce metal oxides to pure metal or less reduced metal oxides.

10. 10. The system of claim 9, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are spatially arranged sequentially so that operation of the system can be performed continuously.

11. 10. The system of any one of claims 1 to 9, further comprising a fourth heating vessel or heating zone configured to reduce metal oxides to pure metal or less reduced metal oxides using the biocatalyst.

12. 12. The system of claim 11, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are spatially arranged sequentially such that operation of the system can be performed continuously.

13. 13. The system of any one of claims 1 to 12, further comprising a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

14. 14. The system of any one of claims 1 to 13, further comprising a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

15. 15. The system of any one of claims 1 to 14, wherein the system further comprises a power generation unit configured to combust a portion of the biogas to generate electricity, the power generation unit configured to supply electricity to components in the system.

16. 1. A system for producing carbon negative hydrogen and activated carbon, comprising: a first heating vessel or heating zone configured to dry biomass and produce a dried biomass and a first recovered water stream; a second heating vessel or heating zone configured to pyrolyze the dried biomass and produce a biocatalyst and biogas, the second heating vessel or heating zone in fluid communication with the first heating vessel or heating zone; (i) receiving the biocatalyst; (ii) optionally receiving a first portion of the biogas; and (iii) H ２ a third heating vessel or heating zone in fluid communication with the second heating vessel or heating zone and configured to produce CO and activated carbon; ２ a third heating vessel or heating zone comprising means for recovering the activated carbon; a thermal oxidizer configured to oxidize a second portion of the biogas to generate heat, the thermal oxidizer being in thermal communication with the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone; The system is mass-integrated and heat-integrated, and H ２ 0 kg CO per metric ton ２ 1. A system capable of producing carbon-negative hydrogen characterized by a carbon intensity of less than e.

17. The third heating vessel or heating zone is configured to receive the first portion of the biogas, and the third heating vessel or heating zone is configured to convert a portion of the biogas into the H ２ and CO.

17. The system of claim 16, configured to convert CO.

18. 18. The system of claim 16 or 17, wherein the system further comprises a separation unit configured to separate a second recovered water stream from the biogas.

19. 20. The system of claim 18, wherein the third heating vessel or heating zone is configured with an inlet for receiving the second recovered water stream.

20. The system according to any one of claims 16 to 19, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are spatially arranged sequentially so that operation of the system can be performed continuously.

21. 21. The system of any one of claims 16 to 20, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are configured to operate in countercurrent flow to a solid phase and a gas phase, respectively.

22. 22. The system of any one of claims 16 to 21, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, and the third heating vessel or heating zone are each configured as a vertical solids downflow vessel.

23. 23. The system of any one of claims 16 to 22, wherein the first heating vessel or heating zone, the second heating vessel or heating zone and the third heating vessel or heating zone each comprise an internal vessel lining.

24. The system includes: ２ or a fourth heating vessel or heating zone configured to use the CO to reduce metal oxides to pure metal or less reduced metal oxides.

25. 25. The system of claim 24, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are spatially arranged sequentially such that operation of the system can be performed continuously.

26. 26. The system of any one of claims 1 to 25, further comprising a fourth heating vessel or heating zone configured to reduce metal oxides to pure metal or less reduced metal oxides using the biocatalyst.

27. 27. The system of claim 26, wherein the first heating vessel or heating zone, the second heating vessel or heating zone, the third heating vessel or heating zone, and the fourth heating vessel or heating zone are spatially arranged sequentially such that operation of the system can be performed continuously.

28. 28. The system of any one of claims 16-27, further comprising a dry biomass pelletizer configured to pelletize the dry biomass, the dry biomass pelletizer in fluid communication with the first heating vessel or heating zone and the second heating vessel or heating zone.

29. 29. The system of any one of claims 16-28, wherein the system further comprises a biocatalyst pelletizer configured to pelletize the biocatalyst, the biocatalyst pelletizer in fluid communication with the second heating vessel or heating zone and the third heating vessel or heating zone.

30. 30. The system of any one of claims 16 to 29, wherein the system further comprises a power generation unit configured to combust a portion of the biogas to generate electricity, the power generation unit configured to supply electricity to components in the system.

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