Biomass pyrolysis integrated with bioreduction of metal ores, hydrogen production, and / or activated carbon production

Abstract

Improved processes and systems for producing renewable hydrogen suitable for reducing metal ores and for producing activated carbon are disclosed. Some variations provide a process that includes pyrolyzing biomass to produce a carbon-containing bio-reagent and a pyrolysis off-gas, converting the pyrolysis off-gas to additional reducing gas and / or heat, reacting at least a portion of the bio-reagent with a reactant to produce the reducing gas, and chemically reducing metal oxides in the presence of the reducing gas. Some variations provide a process for producing renewable hydrogen by biomass pyrolysis to produce a bio-reagent, converting the bio-reagent to a reducing gas, and separating and recovering hydrogen from the reducing gas. A reducing gas composition for reducing metal oxides is provided that includes renewable hydrogen by hydrogen isotope analysis. The reacted bio-reagent can also be recovered as an activated carbon product. Many variations are disclosed.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 116,403, filed November 20, 2020, and U.S. Provisional Patent Application No. 63 / 130,460, filed December 24, 2020, each of which is incorporated by reference herein in its entirety.

[0002] FIELD OF THE INVENTION The present disclosure relates to processes, systems, and apparatus for the treatment of metal ores to produce metals using carbon-containing reagents, as well as processes, systems, and apparatus for hydrogen production and activated carbon production from carbon-containing reagents. [Background technology]

[0003] Carbonaceous reagents are traditionally produced from fossil fuels. Carbonaceous materials include fossil resources such as natural gas, petroleum, coal, and lignite, or renewable resources such as lignocellulosic biomass and various carbon-enriched wastes. Converting renewable resources into carbonaceous reagents poses technical and economic challenges resulting from feedstock variability, operational difficulties, and capital intensity. The increasing economic, environmental, and social costs associated with fossil resources make renewable resources an attractive alternative to fossil resources in the production of carbonaceous reagents.

[0004] Historically, the slow pyrolysis of wood has been carried out in large piles, in simple batch processes, and without emission controls. Traditional charcoal production techniques are not only energy inefficient but also highly polluting. Scaling up such processes for continuous, commercial-scale production of high-quality carbon while managing the energy balance and controlling emissions presents economic and practical challenges. Summary of the Invention

[0005] Disclosed herein is a process comprising: Providing a biomass feedstock; pyrolyzing a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; reacting the biological reagent with the selected reactant, thereby generating a reducing gas; and b. chemically reducing the selected metal oxide in the presence of a reducing gas, thereby producing a reduced form of the selected metal oxide.

[0006] The pyrolysis off-gas can be oxidized, thereby producing heat. In some embodiments, the process can further include recovering the biological reagent continuously or periodically during the reaction, or finally after the reaction, thereby producing a recovered biological reagent that is activated carbon.

[0007] Pyrolysis can be carried out at pyrolysis temperatures ranging from about 250° C. to about 1250° C. or any number therebetween, or from about 300° C. to about 700° C. or any number therebetween. Pyrolysis can be carried out for pyrolysis times ranging from about 10 seconds to about 24 hours or any number therebetween.

[0008] The reaction can be carried out at a reaction temperature ranging from about 300°C to about 1200°C or any number therebetween, for example, from about 400°C to about 1000°C or any number therebetween. The reaction can be carried out for a reaction time ranging from about 1 second to about 1 hour or any number therebetween.

[0009] The chemical reduction can be carried out at a reduction temperature ranging from about 500° C. to about 2000° C. or any number therebetween, for example, from about 700° C. to about 1800° C. or any number therebetween. The chemical reduction can be carried out for a reduction time ranging from about 30 minutes to about 48 hours or any number therebetween.

[0010] In some embodiments, the biomass feedstock is softwood chips, hardwood chips, timber harvest residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugarbeet, sugarbeet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, The waste material may be fruit shells, fruit stems, fruit peels, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pomace, 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 trimmings, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or a combination thereof.

[0011] The bioreagent can comprise from about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% carbon by weight, or any number therebetween. Such carbon is total carbon, which is the sum of fixed carbon and volatile carbon. The bioreagent can comprise from about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% fixed carbon by weight, or any number therebetween.

[0012] The selected metal oxide may be iron oxide, copper oxide, nickel oxide, magnesium oxide, manganese oxide, aluminum oxide, tin oxide, zinc oxide, cobalt oxide, chromium oxide, tungsten oxide, molybdenum oxide, or a combination or derivative thereof. The selected metal oxide may be iron ore, which may be hematite, magnetite, limonite, taconite, or a combination or derivative thereof.

[0013] The reduced form of the selected metal oxide can be a fully reduced metal. The reduced form of the selected metal oxide can be a second metal oxide having a lower oxidation state than the selected metal oxide. A mixture of a fully reduced metal and a second metal oxide can also be produced from the starting metal oxide.

[0014] In some embodiments, the process further includes oxidizing the pyrolysis off-gas, thereby generating heat, which is utilized for heating in the pyrolysis. Alternatively or additionally, the heat can be utilized for heating in the reaction. Alternatively or additionally, the heat can be utilized for heating in the chemical reduction.

[0015] In some embodiments, the reducing gas comprises hydrogen in a range from about 10 mol% to about 25 mol%, or any number therebetween, hi certain embodiments, the reducing gas comprises at least 25 mol% hydrogen.

[0016] In some embodiments, the reducing gas comprises carbon monoxide in the range of about 10 mol% to about 25 mol%, or any number therebetween, hi certain embodiments, the reducing gas comprises at least 25 mol% carbon monoxide.

[0017] In some embodiments, between about 50% and about 90% by weight of the volatile carbon in the generated bioreagent is directed toward the reducing gas, or any number therebetween. In some embodiments, essentially all of the volatile carbon in the generated bioreagent is directed toward the reducing gas.

[0018] The process may further include determining the hydrogen content of the reducing gas using a water-gas shift reaction. In some embodiments, whether or not a water-gas shift reaction is performed, the process may further include separating hydrogen from the reducing gas and recovering the hydrogen. The hydrogen may be separated from the reducing gas using a separation technique. In some embodiments, the separation technique may include pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation.

[0019] In some embodiments, the selected reactant in the reaction of the biological reagent is water. In other embodiments, the selected reactant in the reaction is oxygen, which is present in air, pure oxygen, concentrated oxygen, ozone, or a combination thereof. In some embodiments, the selected reactant in the reaction is or includes a combination of water (e.g., water vapor) and oxygen.

[0020] In some embodiments, the reaction utilizes a fixed bed reactor or a rotary kiln, hi some embodiments, the reaction utilizes a fluidized bed reactor.

[0021] The pyrolysis off-gas can be partially oxidized, thereby generating additional reducing gas and heat. In some embodiments, the chemical reduction further comprises chemically reducing the selected metal oxide in the presence of an additional reducing gas. When the pyrolysis off-gas is converted to an additional reducing gas, the additional reducing gas can comprise hydrogen in a range of about 20 mol% to about 40 mol%, or any number therebetween. The additional reducing gas can comprise carbon monoxide in a range of about 20 mol% to about 40 mol%, or any number therebetween.

[0022] In some embodiments, the process further comprises recovering the reduced form of the selected metal oxide.

[0023] The process may be co-located, for example, at a metal oxide mine or at a metal oxide processing plant such as a steel mill, taconite plant, or direct reduced iron plant.

[0024] In some embodiments, the chemical reduction occurs in a metal ore furnace. In some embodiments, the chemical reduction occurs upstream of a metal ore furnace. The metal ore furnace can be a blast furnace, a direct reduction metal furnace, a top gas recirculation blast furnace, a shaft furnace, a reverberatory 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 hearth furnace, a continuous chain furnace, a pusher furnace, a rotary hearth furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, or a combination thereof.

[0025] In some embodiments, the pyrolysis and chemical reduction of the biomass feedstock occurs in the same location. In certain embodiments, all process steps occur in a single location.

[0026] If activated carbon is the desired product, the process can further include continuously or periodically recovering the bioreagent during or after the reaction, thereby producing a recovered bioreagent that is activated carbon. In some embodiments, about 1% to about 99% by weight of the bioreagent produced during pyrolysis, or any number therebetween, e.g., at least about 10%, at least about 50%, or at least about 90% by weight, is recovered as activated carbon. In some embodiments, essentially all of the bioreagent produced during pyrolysis is recovered as activated carbon. In some embodiments, about 50% to about 99% by weight of the fixed carbon in the bioreagent produced during pyrolysis, or any number therebetween, is recovered as activated carbon. In some embodiments, essentially all of the fixed carbon in the bioreagent produced during pyrolysis is recovered as activated carbon.

[0027] The activated carbon can be characterized by an iodine value ranging from about 500 to about 2000, or any number therebetween. The activated carbon can be characterized by an iodine value of at least about 750, at least about 1000, at least about 1500, or at least about 2000.

[0028] Activated carbon is activated carbon14 C / 12 The activated carbon may be characterized by a renewable carbon content ranging from about 90% to about 100%, or any number therebetween, as determined from measurements of C isotope ratios. In some embodiments, the activated carbon may be characterized by a renewable carbon content ranging from about 90% to about 100%, or any number therebetween. 14 C / 12 It can be characterized as a fully renewable activated carbon, as determined from measurements of the C isotope ratio.

[0029] Also disclosed herein is a system. The system disclosed herein comprises: a first reactor configured to pyrolyze a biomass feedstock to produce a carbon-containing bio-reagent and a pyrolysis off-gas; a second reactor configured to react the biological reagent with the selected reactant to produce a reducing gas; a third reactor configured to chemically reduce the selected metal oxide in the presence of a reducing gas to produce a reduced form of the selected metal oxide.

[0030] In some embodiments, the second reactor is configured to continuously, periodically, or eventually remove activated carbon from the second reactor.

[0031] In some embodiments, the system further comprises one or more heating units in thermal communication with the first reactor, the second reactor, or the third reactor, the one or more heating units configured to oxidize the pyrolysis off-gas to generate heat.

[0032] In some embodiments, the first reactor is configured to operate at a pyrolysis temperature ranging from about 250° C. to about 1250° C., or any number therebetween, such as from about 300° C. to about 700° C., or any number therebetween. The first reactor can be configured to operate at a pyrolysis time ranging from about 10 seconds to about 24 hours, or any number therebetween.

[0033] In some embodiments, the second reactor is configured to operate at a reaction temperature ranging from about 300° C. to about 1200° C., or any number therebetween, such as from about 400° C. to about 1000° C., or any number therebetween. The second reactor can be configured to operate at a reaction time ranging from about 1 second to about 1 hour, or any number therebetween.

[0034] In some embodiments, the third reactor is configured to operate at a reduction temperature ranging from about 500° C. to about 2000° C., or any number therebetween, such as from about 700° C. to about 1800° C., or any number therebetween. The third reactor can be configured to operate at a reduction time ranging from about 30 minutes to about 48 hours, or any number therebetween.

[0035] The first reactor is configured to process biomass feedstock, such as softwood chips, hardwood chips, timber harvest residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugarbeet, sugarbeet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, fruit shells, fruit stems. , fruit peelings, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pomace, 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 trimmings, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof.

[0036] The third reactor can be configured to reduce a metal oxide, such as iron oxide, copper oxide, nickel oxide, magnesium oxide, manganese oxide, aluminum oxide, tin oxide, zinc oxide, cobalt oxide, chromium oxide, tungsten oxide, molybdenum oxide, or a combination thereof. The metal oxide can be a metal ore, such as hematite, magnetite, limonite, taconite, or a combination thereof. The reduced form of the selected metal oxide can be a fully reduced metal or a second metal oxide having a lower oxidation state than the selected metal oxide.

[0037] In some embodiments, there is a heating unit in thermal communication with the first reactor. In some embodiments, there is a heating unit in thermal communication with the second reactor. In some embodiments, there is a heating unit in thermal communication with the third reactor. There may be separate heating units in thermal communication with each reactor, or there may be one or more integrated heating units in thermal communication with multiple reactors.

[0038] In some embodiments, the second reactor is configured to increase the hydrogen content of the reducing gas using the water-gas shift reaction.

[0039] In some embodiments, the system further comprises an additional reactor in fluid communication with the second reactor, the additional reactor configured to increase the hydrogen content of the reducing gas via a water-gas shift reaction.

[0040] In some embodiments, the system further comprises a separation unit configured to separate hydrogen from the reducing gas, which may be selected from, for example, a pressure swing adsorption unit, a molecular sieve membrane, or a cryogenic distillation unit.

[0041] The second reactor can be a fixed bed reactor, a fluidized bed reactor, a rotary kiln, or another type of reactor.

[0042] In some embodiments, the system further comprises an off-gas reactor configured to partially or fully oxidize the pyrolysis off-gas to produce additional reducing gas. The off-gas reactor can be in fluid communication with the third reactor.

[0043] In some embodiments, the second reactor is further configured to receive pyrolysis off-gas and convert it to additional reducing gas.

[0044] In some embodiments, there is an outlet from the third reactor configured to recover the reduced form of the selected metal oxide.

[0045] In some embodiments, the system can be co-located at a metal oxide mine. The system can be co-located at a metal oxide processing plant, such as a steel mill, a taconite plant, or a direct reduced iron plant.

[0046] In some embodiments, the third reactor is a metal ore furnace. In some embodiments, the third reactor is upstream of the metal ore furnace. The metal ore furnace can be selected from a blast furnace, a direct reduction metal furnace, a top gas recirculation blast furnace, a shaft furnace, a reverberatory 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 hearth furnace, a continuous chain furnace, a pusher furnace, a rotary hearth furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, or a combination thereof.

[0047] In some embodiments, the first reactor and the third reactor are co-located, hi some embodiments, the entire system is located at a single location.

[0048] The second reactor can be configured to continuously or periodically remove activated carbon from the second reactor. Alternatively or additionally, the second reactor can be configured to eventually (at the end of the operating period) remove activated carbon from the second reactor. The activated carbon can be characterized by an iodine number of at least about 500. The activated carbon can be 14 C / 12 It can be characterized as a fully renewable activated carbon, as determined from measurements of the C isotope ratio.

[0049] Also disclosed herein is a metal product, the metal product comprising: Providing a biomass feedstock; pyrolyzing a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; reacting the biological reagent with a selected reactant, thereby generating a reducing gas; chemically reducing the selected metal oxide in the presence of a reducing gas, thereby producing a reduced form of the selected metal oxide; and recovering a metal product comprising a reduced form of the selected metal oxide.

[0050] In some embodiments, the process further comprises oxidizing the pyrolysis off-gas, thereby producing heat.

[0051] In some embodiments, the process further comprises continuously or periodically recovering the bio-reagent during or after the reaction, thereby producing a recovered bio-reagent that is activated carbon.

[0052] In some embodiments, the chemical reduction is carried out at a reduction temperature ranging from about 500° C. to about 2000° C., or any number therebetween, such as from about 700° C. to about 1800° C., or any number therebetween. The chemical reduction can be carried out for a reduction time ranging from about 30 minutes to about 48 hours, or any number therebetween.

[0053] The selected metal oxide can be iron oxide, copper oxide, nickel oxide, magnesium oxide, manganese oxide, aluminum oxide, tin oxide, zinc oxide, cobalt oxide, chromium oxide, tungsten oxide, molybdenum oxide, or a combination thereof. Exemplary metal oxides are iron ores, such as hematite, magnetite, limonite, taconite, or a combination thereof. The reduced form can be a fully reduced metal or a second metal oxide having a lower oxidation state than the selected metal oxide.

[0054] The selected reactant in the reaction can be water, oxygen, or a mixture thereof. The oxygen can be present in air, pure oxygen, enriched oxygen, ozone, or a combination thereof.

[0055] In some embodiments, the reducing gas comprises hydrogen in a range of about 10 mol% to at least about 25 mol%, or any number therebetween. In some embodiments, the reducing gas comprises carbon monoxide in a range of about 10 mol% or at least about 25 mol%, or any number therebetween.

[0056] In some embodiments, the metal product is produced by a process further comprising increasing the hydrogen content of the reducing gas using the water-gas shift reaction.

[0057] In some embodiments, the pyrolysis off-gas is partially or fully oxidized, thereby generating additional reducing gas and heat. In some embodiments, additional reducing gas can be utilized in chemical reduction to chemically reduce selected metal oxides.

[0058] In various embodiments, the metal products include iron, copper, nickel, magnesium, manganese, aluminum, tin, zinc, cobalt, chromium, tungsten, molybdenum, or combinations thereof.

[0059] Also disclosed herein is a renewable hydrogen product. The renewable hydrogen product may be: Providing a biomass feedstock; pyrolyzing a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; reacting the biological reagent with a selected reactant, thereby generating a reducing gas; Separating hydrogen from the reducing gas; and recovering a renewable hydrogen product comprising hydrogen.

[0060] In some embodiments, the process further comprises oxidizing the pyrolysis off-gas, thereby producing heat.

[0061] In some embodiments, separating the hydrogen from the reducing gas comprises separating the hydrogen using a separation technique such as pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation.

[0062] In some embodiments, the process further comprises continuously or periodically recovering the bio-reagent during or after the reaction, thereby producing a recovered bio-reagent that is activated carbon.

[0063] Hydrogen is a hydrogen isotope 2 H / 1 The hydrogen may be characterized as having a renewable hydrogen content ranging from about 50% to about at least about 99% or any number therebetween according to H analysis. In some hydrogen products, the hydrogen is characterized as at least 90% renewable hydrogen or at least 95% renewable hydrogen. In some hydrogen products, the hydrogen is characterized as essentially fully renewable hydrogen.

[0064] Hydrogen contained in and separated from the reducing gas 2 H / 1 The H isotope ratio can range from about 0.0002 to about 0.001 or any number therebetween, for example, from about 0.0002 to about 0.005 or any number therebetween.

[0065] In some embodiments, the hydrogen is characterized as fully renewable hydrogen, and any residual carbon contained in the hydrogen product is 14 C / 12 It is essentially fully renewable carbon, as determined from measurements of C isotope ratios.

[0066] The selected reactant in the reaction can be water, oxygen, or a mixture thereof. The oxygen can be present in air, pure oxygen, enriched oxygen, ozone, or a combination thereof.

[0067] In some embodiments, the reducing gas comprises hydrogen in a range of between about 10 mol% or at least about 25 mol%, or any number of moles. In some embodiments, the reducing gas comprises carbon monoxide in a range of between about 10 mol% or at least about 25 mol%, or any number of moles.

[0068] In some embodiments, the hydrogen product is produced by a process further comprising increasing the hydrogen content of the reducing gas using the water-gas shift reaction.

[0069] In some embodiments, the pyrolysis off-gas is partially or fully oxidized, thereby producing additional reducing gas and heat.

[0070] In some embodiments, hydrogen is separated using pressure swing adsorption, molecular sieve membrane separation, cryogenic distillation, or a combination thereof.

[0071] The hydrogen product can comprise between about 50 mole percent and about 90 mole percent hydrogen, or any number therebetween, hi some embodiments, the hydrogen product comprises at least 90 mole percent hydrogen.

[0072] In some embodiments, the hydrogen product contains at most about 1 mole percent nitrogen, or is substantially free of nitrogen.

[0073] Further disclosed herein are reducing gas compositions that can be utilized to reduce metal oxides, the reducing gas composition comprising at least about 25 mole percent hydrogen, the hydrogen being a hydrogen isotope. 2 H / 1 According to H analysis, it is at least about 50% renewable hydrogen.

[0074] In some embodiments, the reducing gas composition comprises a range of about 50 mol% to at least about 90 mol% hydrogen, or any number therebetween, such as about 75 mol% or at least about 90 mol% hydrogen, or any number therebetween.

[0075] In some embodiments, hydrogen is a hydrogen isotope 2 H / 1 In certain embodiments, the hydrogen is characterized as renewable hydrogen in the range of about 80% to at least about 99%, or any number therebetween, according to H analysis. 2 H / 1 In certain embodiments, the hydrogen is characterized as being at least about 90% renewable according to H analysis. 2 H / 1 It is characterized as essentially fully renewable hydrogen according to H analysis.

[0076] In some embodiments, the reducing gas composition can further comprise a carbon-containing gas comprising CO, CO, or CH, or the reducing gas composition can further comprise a carbon-containing gas consisting essentially of CO, CO, or CH. In some embodiments, the carbon-containing gas is 14 C / 12 The hydrogen is preferably at least about 90% renewable, or essentially completely renewable, as determined from measurements of the C isotope ratio, ranging from about 50% to at least about 99%, or any number therebetween. When the reducing gas composition includes a carbon-containing gas, the hydrogen is preferably at least about 90% renewable, or essentially completely renewable, as determined from measurements of the C isotope ratio. 2 H / 1 It can be characterized as at least 90% renewable hydrogen, or essentially fully renewable hydrogen, according to H analysis.

[0077] In some embodiments, the reducing gas composition further comprises carbon monoxide, wherein the carbon monoxide comprises: 14 C / 12 Renewable in the range of about 50% to about 99%, or any number therebetween, such as at least 90% renewable, or essentially fully renewable, as determined from measurements of C isotope ratios. In some embodiments, when the reducing gas composition further comprises carbon monoxide, the hydrogen is 2 H / 1 In some reducing gas compositions, the molar ratio of hydrogen to carbon monoxide is at least 2.

[0078] In some embodiments, the reducing gas composition comprises at most about 1 mol % N2, at most about 0.5 mol % N2, at most about 0.1 mol % N2, or essentially no N2.

[0079] Further disclosed herein is an activated carbon product, the activated carbon product comprising: Providing a biomass feedstock; pyrolyzing a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; reacting the biological reagent with a selected reactant, thereby generating a reducing gas; and continuously or periodically recovering the biological reagent during or after the reaction, wherein the recovered biological reagent is activated carbon.

[0080] In some embodiments, the activated carbon product is produced by a process that further includes oxidizing the pyrolysis off-gas, thereby producing heat.

[0081] In some embodiments, the activated carbon product is produced by a process further comprising chemically reducing the selected metal oxide in the presence of a reducing gas from the reaction, thereby producing a reduced form of the selected metal oxide.

[0082] In some embodiments, pyrolysis is carried out at a pyrolysis temperature ranging from about 250° C. to about 1250° C., or any number therebetween, such as from about 300° C. to about 700° C., or any number therebetween. Pyrolysis can be carried out for a pyrolysis time ranging from about 10 seconds to about 24 hours, or any number therebetween.

[0083] In some embodiments, the reaction is carried out at a reaction temperature ranging from about 300° C. to about 1200° C., or any number therebetween, such as from about 400° C. to about 1000° C., or any number therebetween. The reaction can be carried out for a reaction time ranging from about 1 second to about 1 hour, or any number therebetween.

[0084] In some embodiments, the bio-reagent produced upon pyrolysis comprises from about 50% by weight or at least about 99% by weight carbon, or any number in between, e.g., from about 50% by weight or at least about 75% by weight carbon, or any number in between. The bio-reagent can comprise from about 50% by weight fixed carbon or at least about 99% by weight fixed carbon, or any number in between, e.g., from about 50% by weight or at least about 75% by weight fixed carbon, or any number in between.

[0085] In some embodiments, the reducing gas comprises hydrogen ranging from about 10 mole % hydrogen or at least about 25 mole % hydrogen, or any number therebetween.

[0086] In some embodiments, the reducing gas comprises carbon monoxide ranging from about 10 mole percent carbon monoxide or at least about 25 mole percent carbon monoxide, or any number therebetween.

[0087] In some embodiments, the activated carbon product is produced by a process further comprising increasing the hydrogen content of the reducing gas via the water-gas shift reaction.

[0088] In some embodiments, the selected reactant in the reaction is water, oxygen, or a mixture thereof. The oxygen may be present in air, pure oxygen, concentrated oxygen, ozone, or a combination thereof.

[0089] In some embodiments, between about 10% and 99% by weight, or any number therebetween, of the bioreagent produced by pyrolysis is recovered as activated carbon, for example, from about 50% by weight or at least about 90% by weight, or any number therebetween.

[0090] In some embodiments, between about 50% and at least about 99% by weight of the fixed carbon in the produced bio-reagent, or any number therebetween, or essentially all thereof, is recovered as activated carbon.

[0091] The activated carbon can be characterized by an iodine value ranging from about 500 to about 2000, or any number therebetween. In some embodiments, the activated carbon is characterized by an iodine value of at least about 1000, at least about 1500, or at least about 2000.

[0092] Activated carbon is activated carbon 14 C / 12 In certain embodiments, the activated carbon may be characterized by a renewable carbon content of at least 90% as determined from C isotope ratio measurements. 14 C / 12 It is characterized as an essentially fully renewable activated carbon, as determined from C isotope ratio measurements. [Brief explanation of the drawings]

[0093] [Figure 1] 1 is a simplified block flow diagram of a process for converting biomass feedstock into a reducing gas composition that is optionally utilized to reduce metal oxides to metal products in some embodiments. Dotted lines indicate optional streams and units.

[0094] [Figure 2]1 is a simplified block flow diagram of a process for converting biomass feedstock into a reducing gas composition that is utilized to produce renewable hydrogen in some embodiments. Dotted lines indicate optional streams and units.

[0095] [Figure 3] 1 is a simplified block flow diagram of a process for converting biomass feedstock into activated carbon and a reducing gas composition, according to some embodiments. Dotted lines indicate optional streams and units.

[0096] [Figure 4] 1 is a simplified block flow diagram of a process for converting biomass feedstock into activated carbon and a reducing gas composition utilized to reduce metal oxides to metal products, in some embodiments. Dotted lines indicate optional streams and units. DETAILED DESCRIPTION OF THE INVENTION

[0097] This description enables one skilled in the art to make and use the disclosed disclosure and describes several embodiments, adaptations, variations, alternatives, and uses of the present disclosure. These and other embodiments, features, and advantages of the present disclosure will become more apparent to those skilled in the art upon review of the following detailed description of the disclosure in conjunction with the accompanying drawings.

[0098] For the purpose of enabling technical disclosure, various explanations, hypotheses, theories, speculations, assumptions, etc. are disclosed. The present disclosure does not rely on any of these being actually true. None of the explanations, hypotheses, theories, speculations, or assumptions in this detailed description should be construed as limiting the scope of the present disclosure in any way.

[0099] The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed embodiments.

[0100] Various conversion technologies exist for converting biomass feedstocks into high-carbonaceous materials. Pyrolysis is a process for thermally converting solid materials in the complete absence of an oxidant (air or oxygen) or with a limited supply of oxidant such that oxidation does not occur appreciably. Depending on the process conditions and additives, biomass pyrolysis can be adjusted to produce widely varying amounts of gas, liquids, and solids. Lower process temperatures and longer vapor residence times favor the production of solids. High temperatures and longer residence times increase biomass conversion to synthesis gas, while moderate temperatures and short vapor residence times are generally optimal for producing liquids. There is a need for a pyrolysis process specifically targeted at optimizing the yield and quality of the solid pyrolysis product as a carbonaceous reagent.

[0101] Metal processing is a very important industry worldwide. For example, with regard to steel (an alloy of iron), the global steel market size is expected to reach US$1 trillion by 2025, according to "Steel Market Size, Share & Trends Analysis 2018-2025," Grand View Research, Inc. (2017). Contractors' growing preference for sustainable, low-cost, and durable building materials is driving the demand for steel in industrial infrastructure and residential projects. In pre-engineered metal buildings with high structural integrity, steel provides essential functions for stability, design flexibility, and aesthetic appeal. Stringent regulations promoting green and energy-efficient buildings are also contributing to the demand for steel, especially in industrial structures.

[0102] Approximately 70% of all steel is made from pig iron, produced by reducing iron oxide in a blast furnace using coke or coal before reduction in a basic oxygen furnace. The use of non-renewable coal or coal-derived coke releases non-renewable carbon dioxide into the atmosphere, in addition to depleting fossil resources.

[0103] Oxygenated iron ore is mined worldwide. The iron ore is taken through a beneficiation process to crush and concentrate the iron fraction, then rolled into pellets (with a binder), heated in a hardening furnace that burns coal for heat, and the pellets are consolidated and transported to a blast furnace, where coke is used to reduce the oxygenated ore to metallic iron. The hardening and coking processes create large amounts of CO2 and other pollutants.

[0104] Metal processing causes significant net CO2 emissions worldwide each year. One of the biggest drawbacks of conventional blast furnaces is the inevitable production of CO2 as iron is reduced from iron oxide by carbon or carbon monoxide (CO). Steelmaking is one of the largest industrial contributors to CO2 emissions in the world today. There is a strong desire to make metal making processes more environmentally friendly.

[0105] Hydrogen is used in a variety of industrial applications, including metal alloying, glass formation, electronics processing (eg, in deposition, cleaning, etching, and reduction), and power generation (eg, for corrosion prevention in pipelines).

[0106] Hydrogen is also used to process crude oil into refined fuels such as gasoline and diesel, or to remove contaminants such as sulfur from these fuels. The use of hydrogen in oil refineries has increased in recent years due to stricter regulations requiring lower sulfur in diesel fuel and increased consumption of lower-quality crude oil, which requires more hydrogen for refining. While refineries produce some by-product hydrogen from catalytic reforming of naphtha, that supply only meets a small portion of their hydrogen demand. Approximately 80% of the hydrogen currently consumed worldwide by refineries is supplied by large-scale hydrogen plants that produce non-renewable hydrogen from natural gas or other hydrocarbon fuels.

[0107] Direct reduction of iron ore using hydrogen has the potential to develop into an important industrial process in steelmaking. 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 co-product shifts toward water rather than carbon dioxide. The environmental benefits are even greater if the hydrogen used in iron ore reduction is renewable hydrogen.

[0108] definition As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, wherever a product is produced, the process can be controlled to produce more than one product, such that if "carbon-metal ore particulates" are produced, "plurality of carbon-metal ore particulates" can be produced. This also applies to compositions including a single component. For example, if a composition includes carbon-metal ore particulates, the composition can include multiple carbon-metal ore particulates.

[0109] 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 may vary depending, at least on particular analytical techniques.

[0110] As used herein, the term "about" means ±20% of a given range, value, or structure, unless otherwise indicated.

[0111] As used 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 recited herein should be understood to include any integer within the recited range, unless otherwise indicated.

[0112] As used herein, "a range from about or a range therebetween," e.g., "a range from about X, Y, or Z or a range therebetween," includes "at least X and at most (either higher or longer) Z."

[0113] As used herein, "biological" refers to materials (either feedstocks, products, or intermediates) containing elements such as carbon that are renewable over time scales of months, years, or decades. Non-biological materials can be non-renewable or renewable over time scales of centuries, millennia, millions of years, or even longer geological time scales. For example, traditional fuel sources of coal and petroleum are non-renewable and non-biological. Biological materials can consist essentially of biological sources. It will be understood by those skilled in the art that naturally sourced or derived biological materials can contain trace amounts of non-biological materials. Furthermore, the processes disclosed herein can be used with non-biological materials, although the beneficial environmental impact may be less significant.

[0114] The three naturally occurring isotopes of carbon, 12 C. 13 C, and 14 C exists. 12 C and 13 C is stable and exists in a natural ratio of about 93:1. 14 C is produced by thermal neutrons from cosmic rays in the upper atmosphere and transported to Earth where it is absorbed by living biological material. 14 C constitutes a negligible portion. However, it is radioactive with a half-life of 5,700 years and is therefore radiometrically detectable. Dead tissue 14It does not absorb C, 14 The amount of C is one of the methods used for radiometric dating of biological materials.

[0115] Plants fix atmospheric carbon through photosynthesis 14 Animals then take in C when they consume the plant, or when they consume other animals that consume the plant. 14 Therefore, living plants and animals absorb the same amount of CO2 as the atmosphere. 14 C vs. 12 When an organism dies, it stops exchanging carbon with the atmosphere and therefore no more new 14 C is not incorporated. Radioactive decay then occurs in living organisms. 14 It gradually depletes C. This effect is the basis of radiocarbon dating.

[0116] Fossil fuels such as coal are primarily made from plant material deposited millions of years ago. 14 This is equivalent to thousands of half-lives of C, so essentially all of the carbon in fossil fuels 14 C is decaying. Fossil fuels are harmful to the atmosphere because they were originally formed from living organisms. 13 C is depleted. Therefore, carbon from fossil fuels is 13 C and 14 It is depleted in both C.

[0117] This difference between the carbon isotopes of recently depleted organic matter, such as from renewable sources, and the carbon isotopes of fossil fuels, such as coal, allows for the determination of the source of the carbon in the composition, specifically whether the carbon in the composition is derived from a renewable resource or a fossil fuel, in other words, whether a renewable resource or a fossil fuel was used to produce the composition.

[0118] Biomass is a term used to describe biologically produced or living matter. Biomass refers to the mass of living organisms, including 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 trunks, as well as the roots of trees and the rhizomes of grasses. The chemical energy contained in biomass comes from solar energy using the natural process of photosynthesis. This is the process by which plants take in carbon dioxide and water from their surroundings and convert them into sugars, starch, cellulose, hemicellulose, and lignin using energy from sunlight. Biomass is useful in that it is effectively stored solar energy. Furthermore, biomass is the only renewable carbon source.

[0119] As used herein, "combustion stoichiometric amount of oxygen" is the amount of oxygen, whether present in air, pure oxygen, or oxygen-enriched air, that is not in stoichiometric excess and that completely oxidizes carbon-containing or hydrogen-containing components to CO or HO, respectively. When pyrolysis off-gas is intentionally oxidized at less than the stoichiometric amount for combustion, the oxygen utilized as a percentage of the combustion stoichiometry of oxygen can be at least about 10% to at most about 99%, at least about 25% to at most about 90%, or at least about 40% to at most about 80%. In various embodiments, this percentage 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 percentages are on a molar basis where the oxygen is in the O form.

[0120] As used herein, "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. "Comprising" is a term of art used in claim language indicating that specified claim elements are essential, although other claim elements may be added and still form a construct within the scope of the present 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 or consist essentially of X, Y, and Z.

[0121] As used herein, "consisting of" excludes any unspecified element, step, or ingredient. When the phrase "consisting of" appears in a clause in the body of a claim rather than immediately following the preamble, the phrase 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 scope of a claim to those specified elements or method steps, plus those that do not materially affect the basis of the claimed subject matter.

[0122] As used herein, a "derivative" is a compound, molecule, or ion derived from another substance by chemical reaction. The substance from which the derivative is derived is an additive. A derivative is also an additive.

[0123] As used herein, "high carbon," as in "high-carbon bioreagent," indicates that the bioreagent has a high carbon content relative to the raw material used to generate the high-carbon bioreagent. A high-carbon bioreagent can contain at least about half of its weight as carbon. For example, a high-carbon bioreagent can contain 55-99 weight percent carbon, or any number therebetween, e.g., at least about 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 weight percent carbon.

[0124] As used herein, "high-carbon bioreagent" describes a material that can be produced by the disclosed processes and systems. No limitations regarding carbon content or any other concentration should be implied by the term itself, but only by reference to specific embodiments. For example, when a feedstock containing a low carbon content is subjected to the disclosed processes, the product is a high-carbon bioreagent that is highly enriched in carbon relative to the starting material (high yield of carbon), but is nevertheless relatively low in carbon (low purity carbon), containing at most about 50% carbon by weight.

[0125] As used herein, the terms "include," "have," and "comprise" are used interchangeably and these terms and variations thereof are intended to be interpreted as open-ended.

[0126] As used herein, a "metal ore" is a metal-containing material in which the desired metal is not present in a 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.

[0127] The use of the word "or" in reference to 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 the convention (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, a system 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.). When a convention similar to "at least one of A, B, or C, etc." is used, generally such configuration is intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include, but is not limited to, a system having only A, only B, only C, A and B together, A and C together, B and C together, or A, B and C together, etc.).

[0128] As used herein, "pellets" is synonymous with "briquettes" and can refer to pellets, briquettes, pellet / briquettes, or similar terms, all referring to an agglomerated body rather than a loose powder. For convenience, the term "pellets" is generally used. The shape of the pellets is not limited to spherical or nearly spherical. Pellet shapes can be spherical (round or ball-shaped), cubic (square), octagonal, hexagonal, honeycomb / honeycomb, elliptical, oval, cylindrical, rod-shaped, loaf-shaped, pillow-shaped, random, or combinations thereof.

[0129] 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 at most about 10%, 5%, 1%, 0.5%, 0.1%, or 0.01% of the oxygen (on an O2 molar basis) required for complete combustion. In some embodiments, pyrolysis is carried out in the absence of oxygen.

[0130] As used herein, a "reagent" is a material in its 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 does not necessarily have to be 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 is added. For example, a reagent can be introduced into a metal to impart certain strength properties to the metal. A reagent can be a substance of sufficient purity (typically carbon purity in the present context) to be used in chemical analysis or physical testing.

[0131] As used herein, "renewable hydrogen" refers to hydrogen that can be used to react with carbon or CO to form H, regardless of the renewability of the hydrogen contained in the water (H2O) reactant. 2 H / 1 It is determined by correlating the H isotope ratio with the recyclability of the starting material. 2 H / 1 The H isotope ratio correlates with the renewable potential of hydrogen. 2 H / 1 The H isotope ratio indicates a greater renewable hydrogen content.

[0132] As used herein, "total carbon" is the sum of fixed and non-fixed carbon present in the volatile materials. In some embodiments, component weight percentages are on an absolute basis, which is assumed unless otherwise stated. In other embodiments, component weight percentages are on a dry and ash-free basis.

[0133] As used herein, a "zone" is a region of space within a single physical unit, physically separated units, or any combination thereof. With respect to continuous reactors, zone boundaries may be related to structures such as the presence of flights within the reactor or separate heating elements for providing heat to separate zones. Alternatively or additionally, zone boundaries in continuous reactors may be related to functions such as distinct temperatures, fluid flow patterns, solid flow patterns, or extent of reaction. In single batch reactors, "zones" are operating regimes in time rather than space. There is not necessarily an abrupt transition from one zone to another. For example, the boundary between the preheat zone and the pyrolysis zone may be somewhat arbitrary. Some amount of pyrolysis may occur in part of the preheat zone, and some amount of "preheating" may continue to occur in the pyrolysis zone. The temperature profile in the reactor is typically continuous, including the zone boundaries within the reactor.

[0134] Processes and Systems Disclosed herein are improved processes and systems for producing renewable hydrogen for reducing metal ores and for other industrial uses.

[0135] Some embodiments are based on processes and systems for producing renewable reducing gas from biomass, which can be utilized to reduce metal oxides or for the production of renewable hydrogen.

[0136] In some embodiments, a first reactor is supplied with wood or another biomass source. The first reactor is a pyrolysis reactor configured to produce carbon and pyrolysis off-gas (also referred to as biogas) from the feedstock. The second reactor is configured to receive carbon and reactants, such as water or oxygen, for reacting the carbon to form 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-enriched product. Alternatively or additionally, a third reactor can be configured to directly or indirectly receive (a) the reduced gas from the second reactor and (b) metal oxides, where the metal oxides are operated under reducing conditions effective to convert the metal oxides to reduced metals, and the reduced off-gas includes at least HO, and the reduced off-gas can further include CO and CO. The pyrolysis off-gas is oxidized, thereby generating heat that can be utilized to heat the first, second, or third reactors. The process and system can be located on-site at a metal oxide mine, such as an iron ore mine, or at a metal oxide processing plant, such as a taconite processing plant. The process and system reduces or eliminates the pollution and cost of incineration, pelletizing, and transportation of iron ore (or other metal oxides). The process and system also reduces the pollution and cost of coking coal to make metallurgical coke or the pollution and cost of transporting petroleum coke to a blast furnace. The process and system can also improve the metal purity of the final product.

[0137] Variations of the present disclosure are described, including with reference to the accompanying drawings (FIGS. 1, 2, 3, and 4), which are not intended to be limiting but rather to illustrate various embodiments.

[0138] 1 is a simplified block flow diagram of a process and system for converting biomass feedstock to a reducing gas composition that is optionally utilized to reduce metal oxides to metal products in some embodiments. Dotted lines indicate optional streams and units.

[0139] 2 is a simplified block flow diagram of a process and system for converting biomass feedstock into a reducing gas composition that is utilized to produce renewable hydrogen in some embodiments. Dotted lines indicate optional streams and units.

[0140] 3 is a simplified block flow diagram of a process for converting biomass feedstock into activated carbon and a reducing gas composition, in some embodiments. Dotted lines indicate optional streams and units.

[0141] 4 is a simplified block flow diagram of a process for converting biomass feedstock to activated carbon and an in situ reducing gas composition for reducing metal oxides to metal products, in some embodiments. The dotted lines indicate optional streams and units. The second reactor zone can be switched so that the carbon bed is physically above the metal oxide bed.

[0142] Some variations are: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a carbon-containing bioreagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the biological reagent with the selected reactant, thereby generating a reducing gas; (e) optionally chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide.

[0143] Some embodiments include: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a carbon-containing bioreagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the biological reagent with the selected reactant, thereby generating a reducing gas; (e) optionally chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) optionally, continuously or periodically recovering the bio-reagent during step (d) or finally after step (d) (e.g., removing carbon from the reactor in a batchwise manner), wherein the recovered bio-reagent is activated carbon.

[0144] In some embodiments, step (b) is carried out at a pyrolysis temperature selected from about 250°C to about 1250°C, e.g., about 300°C to about 700°C, see specifics provided in the summary above. 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, see specifics provided in the summary above. Generally, lower pyrolysis temperatures require longer pyrolysis times, while higher pyrolysis temperatures allow for shorter pyrolysis times.

[0145] In some embodiments, step (d) 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, see specifics provided in the overview above. In these or other embodiments, step (d) is carried out for a reaction time selected from about 1 second to about 1 hour, see specifics provided in the overview above. Generally, the reaction temperature for forming the reducing gas is selected to achieve the desired chemical reaction. The reaction time can be determined by mass and heat transfer to and from the reaction solids (smaller particles can be converted in shorter reaction times).

[0146] In some embodiments, step (e) is carried out at a reduction temperature selected from about 500°C to about 2000°C, e.g., about 700°C to about 1800°C, see specifics provided in the summary above. In these or other embodiments, step (e) is carried out for a reduction time selected from about 30 minutes to about 48 hours, see specifics provided in the summary above. Generally, lower reduction temperatures require longer reduction times, while higher reduction temperatures allow for shorter reduction times.

[0147] In some embodiments, the biomass feedstock is softwood chips, hardwood chips, timber harvest residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugarbeet, sugarbeet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, oats ... The biomass feedstock can be any of the following: fruit shells, fruit stems, fruit peels, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pomace, 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 trimmings, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof. The biomass feedstock can include carbon, hydrogen, and oxygen.

[0148] The bio-reagent produced in step (b) can comprise at least about 50%, at least about 75%, or at least about 90% by weight carbon (also known as total carbon), with particular reference to those provided in the summary above. In various embodiments, the bio-reagent comprises at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% by weight carbon, with particular reference to those provided in the summary above. Total carbon is the sum of fixed and non-fixed carbon present in the volatile materials. In some embodiments, component weight percentages are on an absolute basis, which is assumed unless otherwise specified. In other embodiments, component weight percentages are on a dry and ash-free basis.

[0149] The bio-reagent produced in step (b) can comprise at least about 50%, at least about 75%, or at least about 90% by weight of fixed carbon, with particular reference to those provided in the summary above. In various embodiments, the bio-reagent comprises at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% by weight of fixed carbon, with particular reference to those provided in the summary above.

[0150] The carbon contained within the bio-reagent can be at least about 50%, at least about 75%, or at least about 90% by weight fixed carbon, with specific references to those provided in the summary above, and the remainder of the carbon being volatile carbon. In various embodiments, the carbon contains about, at least about, or at most about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100% by weight fixed carbon, with specific references to those provided in the summary above.

[0151] The conditions for step (b) can vary widely depending on the desired composition of the bioreagent and pyrolysis off-gas, the starting material, the type of metal oxide, the reactor configuration, and other factors (described in more detail below). The pyrolysis temperature is a critical parameter and should be controlled. Generally speaking, higher pyrolysis temperatures, e.g., about 600°C to about 850°C, produce more hydrogen in the pyrolysis off-gas and leave less hydrogen in the bioreagent. This is advantageous in embodiments that utilize hydrogen in the off-gas for metal oxide reduction. On the other hand, lower pyrolysis temperatures, e.g., about 400°C to about 600°C, leave more hydrogen in the bioreagent and therefore less hydrogen in the off-gas. This can be advantageous in embodiments, such as the injection of biocarbon into a metal reduction furnace, that utilize hydrogen in the bioreagent for metal oxide reduction. In either scenario, hydrogen can be utilized for metal oxide reduction, which is desirable because it avoids direct CO2 production and thereby improves the environmental footprint by reducing carbon intensity.

[0152] In some embodiments, the metal oxide 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 particular embodiments, the metal ore is an iron ore, such as an iron ore selected from hematite, magnetite, limonite, taconite, or a combination thereof.

[0153] The metal oxides may be contained in beneficiated metal ores, i.e., metal ores that have been processed in one or more beneficiation units. The metal oxides may be contained in particulate form, such as in powder form, of the metal ores.

[0154] When the reducing gas is utilized to chemically reduce a metal oxide, CO, H, or both CO and H chemically react with the metal oxide in a chemical reaction that reduces the metal oxide (e.g., FeO) to the corresponding metal (e.g., Fe) or to a less reduced metal oxide (e.g., FeO is less reduced than FeO). The sensible heat contained within the oxidized pyrolysis off-gas can be used to drive endothermic reactions, whether thermodynamic, kinetic, or both. Skilled chemical engineers will recognize that hot gases are useful for endothermic reactions that require heat. Optionally, hot gases from the oxidation of the pyrolysis off-gas can be used to indirectly heat the reactor or can be heat exchanged with another stream before injection into the reactor. It is also possible for the hot gases to be at a lower temperature than the reaction into which they are injected. In that case, the hot gases can be considered to actually be heated themselves, rather than providing heat. However, in this case, the reactor contents are not cooled as much as occurs with cold gas injection, so endothermic chemical reactions still have the advantage of relatively low overall energy usage compared to conventional approaches.

[0155] In certain embodiments, heat is generated from partial oxidation rather than complete oxidation (combustion) of the pyrolysis off-gas, thereby 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 the pyrolysis or to heat other reactors. Although less heat is produced with partial oxidation versus complete oxidation, more reducing gas is produced, which is useful for metal oxide reduction or hydrogen production.

[0156] In some embodiments, the bio-reagent comprises heavy hydrocarbons obtained during step (b), which may be converted to reducing gases in the second reactor. The heavy hydrocarbons may originate from pyrolysis off-gas or from volatile carbon remaining in the bio-reagent.

[0157] The metal oxide can be, for example, iron oxide, copper oxide, nickel oxide, magnesium oxide, manganese oxide, aluminum oxide, tin oxide, zinc oxide, cobalt oxide, chromium oxide, tungsten oxide, molybdenum oxide, or a combination thereof. In some embodiments, the metal oxide is an iron ore, such as hematite, magnetite, limonite, taconite, or a combination thereof.

[0158] 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 a 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 FeO has an oxidation state of +3.

[0159] In various embodiments, heat is utilized for heating in step (b), or for heating in step (d), or for heating in step (e), or for at least two of these steps, or for all three of these steps.

[0160] In some embodiments, the process further comprises increasing the hydrogen content of the reducing gas via a water-gas shift reaction. Whether or not the hydrogen content is increased, the process can further comprise separating the hydrogen from the reducing gas and subsequently recovering the hydrogen. The hydrogen can be separated from the reducing gas by one or more separation techniques selected from, for example, pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation.

[0161] In some embodiments, the reactant selected in step (d) is water. In some embodiments, the reactant in step (d) is oxygen, which may be present in a form selected from air, pure oxygen, enriched oxygen, ozone, or a combination thereof. Enriched oxygen refers to a gas composition comprising O2 at a concentration of at least about 21% by volume, along with N2 or other gases. In certain embodiments, the reactant selected in step (d) comprises a combination of water and oxygen. Another possible reactant is CO2 in a dry reforming process.

[0162] Step (d) can utilize, 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 the bioreagent. In some embodiments, step (d) utilizes a rotary kiln.

[0163] In some embodiments, in step (c), the pyrolysis off-gas is partially or fully oxidized, thereby generating additional reducing gas and heat. In these embodiments, step (e), in addition to chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), can further include chemically reducing the selected metal oxide in the presence of some or all of the additional reducing gas.

[0164] In some embodiments, the reducing gas is also oxidized, thereby generating heat, which can be utilized for heating in step (b), or for heating in step (d), or for heating in step (e), or for at least two of these steps, or for all three of these steps.

[0165] In some embodiments, the pyrolysis off-gas is converted to additional reducing gas during step (d). For example, some or all of the pyrolysis off-gas from the pyrolysis reactor can be directed to a reactor for converting the bio-reagent to a reducing gas. The same reactant (e.g., water vapor or oxygen) that reacts with the bio-reagent can react with the pyrolysis off-gas, thereby producing additional reducing gas (e.g., CO or H). Alternatively or additionally, the off-gas can be converted to additional reducing gas (e.g., CO or H) through a water-gas shift or other equilibrium reaction. In these embodiments, the reactant that reacts with the off-gas can be the same as or different from the reactant that reacts with the bio-reagent.

[0166] The pyrolysis off-gas, or additional reducing gas generated from the off-gas, can contain at least 10 mol% hydrogen or at least 20 mol% hydrogen, see specifically those provided in the summary above. Independently, the pyrolysis off-gas, or additional reducing gas generated from the off-gas, can contain at least 10 mol% carbon monoxide or at least 20 mol% carbon monoxide. In some embodiments, the pyrolysis off-gas, or additional reducing gas generated from the off-gas, contains hydrogen in a range from or between about 1 mol%, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, or 50 mol% and at least 1 mol%, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, or 50 mol% carbon monoxide.

[0167] In some processes, step (e) is not performed. In other processes, step (e) is performed. When step (e) is performed, the process can include recovering the reduced form of the selected metal oxide, for example, through an outlet port of the reactor. Also, when step (e) is performed, steps (b) and (e) can be performed in the same location.

[0168] In some embodiments, the process is co-located at a metal oxide mine, such as an iron mine.

[0169] In some embodiments, the process is co-located with a metal oxide processing plant, for example, a plant selected from a steel mill, a taconite plant, or a direct reduced iron plant.

[0170] In certain embodiments, the entire process is located at a single site, which may be a greenfield site or an existing site, where the site may include a biomass processing plant, a pyrolysis plant, a coal plant, a metal ore mine, a metal ore processing plant, a gasification plant, a steam reforming plant, or another type of plant.

[0171] In some embodiments, step (e) occurs in or upstream of a metal ore furnace, which may be selected from a blast furnace, a direct reduction metal furnace, a top gas recirculation blast furnace, a shaft furnace, a reverberatory 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 hearth furnace, a continuous chain furnace, a pusher furnace, a rotary hearth furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, or a combination thereof.

[0172] Some variations are: a first reactor for pyrolyzing a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; a second reactor configured to react the biological reagent with the selected reactant, thereby producing a reducing gas; optionally a third reactor configured to chemically reduce the selected metal oxide in the presence of a reducing gas, thereby producing a reduced form of the selected metal oxide; Optionally, the system further comprises one or more heating units in thermal communication with the first reactor, the second reactor, or the third reactor (if present), wherein the one or more heating units are configured to oxidize the pyrolysis off-gas, thereby generating heat.

[0173] Some variations are: a first reactor configured to pyrolyze a biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; a second reactor configured to react the biological reagent with the selected reactant, thereby producing a reducing gas, and optionally configured for continuous, periodic, or eventual removal of activated carbon from the second reactor; optionally a third reactor configured to chemically reduce the selected metal oxide in the presence of a reducing gas, thereby producing a reduced form of the selected metal oxide; Optionally, the system further comprises one or more heating units in thermal communication with the first reactor, the second reactor, or the third reactor (if present), wherein the one or more heating units are configured to oxidize the pyrolysis off-gas, thereby generating heat.

[0174] In some systems, the first reactor is configured to operate at a pyrolysis temperature in the range of about 250°C to about 1250°C, or any range therebetween, such as about 300°C to about 700°C, or any range therebetween. The first reactor can be configured to operate at a pyrolysis time in the range of, for example, about 10 seconds to about 24 or 48 hours, or any range therebetween. Other pyrolysis times are possible, and the pyrolysis time depends on the feedstock, desired products, and other reaction conditions. While the pyrolysis time is critical to the process and products, the time can vary widely.

[0175] In some systems, the second reactor is configured to operate at a reaction temperature in the range of about 300°C to about 1200°C, or any range therebetween, such as about 400°C to about 1000°C, or any range therebetween. The second reactor can be configured to operate at a reaction time selected from, for example, about 1 second to about 1 hour. Other reaction times are possible. As with pyrolysis time, reaction time can vary, but is important for the process and products.

[0176] In some systems, the third reactor is configured to operate at a reduction temperature ranging from about 500°C to about 2000°C, or any range therebetween, such as from about 700°C to about 1800°C, or any range therebetween. The third reactor can be configured to operate at a reduction time ranging from, for example, about 30 minutes to about 48 hours, or any range therebetween. Other reduction times are possible. As with pyrolysis time, reduction time can vary, but is important to the process and products.

[0177] In some embodiments, the biomass feedstock is selected from the group consisting of softwood chips, hardwood chips, timber harvest residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugarbeet, sugarbeet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, fruit extracts, and the like. shells, fruit stems, fruit peels, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pomace, 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 trimmings, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof.

[0178] In some systems, the bioreagent comprises about 50% to about 99% by weight total carbon, or a range therebetween, e.g., at least 75% by weight carbon, or at least 90% by weight carbon. The bioreagent comprises about 50% to about 99% by weight fixed carbon, or a range therebetween, e.g., at least 75% by weight fixed carbon, or at least 90% by weight fixed carbon.

[0179] The metal oxide can be selected from iron oxide, copper oxide, nickel oxide, magnesium oxide, manganese oxide, aluminum oxide, tin oxide, zinc oxide, cobalt oxide, chromium oxide, tungsten oxide, molybdenum oxide, or a combination thereof. In some systems, the metal oxide is an iron ore, such as hematite, magnetite, limonite, taconite, or a combination thereof.

[0180] The reduced form of the selected metal oxide can be a fully reduced metal or a second metal oxide having a lower oxidation state than the selected metal oxide (i.e., in a partial but not complete reduction of the starting metal oxide).

[0181] In some embodiments, the system comprises a heating unit in thermal communication with the first reactor, the second reactor, the third reactor, at least two of such reactors, or all three of such reactors.

[0182] In some systems, the second reactor is configured to increase the hydrogen content of the reducing gas via a water-gas shift reaction. In these or other systems, the system may further include an additional reactor in fluid communication with the second reactor, the additional reactor configured to increase the hydrogen content of the reducing gas via a water-gas shift reaction. The system may further include a separation unit configured to separate hydrogen from the reducing gas. Exemplary separation units are a pressure swing adsorption unit, a molecular sieve membrane, or a cryogenic distillation unit.

[0183] In some systems, the selected reactant is water, which may be in the form of water vapor. In some embodiments, the selected reactant is oxygen. The reactant may be a combination of water and oxygen.

[0184] The second reactor may be, for example, a fixed bed reactor, a rotary kiln, or a fluidized bed reactor.

[0185] In some embodiments, the system further comprises an off-gas reactor configured to partially oxidize the pyrolysis off-gas, thereby producing additional reducing gas. In these embodiments, the off-gas reactor can be in fluid communication with the third reactor.

[0186] In some embodiments, the second reactor is configured to receive some or all of the pyrolysis off-gas to allow its conversion to additional reducing gas. The same reactant (e.g., water vapor) that reacts with the bio-reagent can react with the pyrolysis off-gas, thereby producing additional reducing gas (e.g., CO or H). Figures 1-4 illustrate the optional use of the pyrolysis off-gas to produce more reducing gas, which can be done instead of or in addition to burning the pyrolysis off-gas to generate heat.

[0187] In some embodiments, the one or more heating units are configured to oxidize the reducing gas, thereby generating heat, which can be used to heat the first reactor, the second reactor, or the third reactor (if present).

[0188] The third reactor may or may not be present. In some embodiments, a third reactor is present in the system, and the system includes an outlet from the third reactor configured to recover the reduced form of the selected metal oxide. For example, a screw conveyor can be installed at or near the bottom of the third reactor to continuously or periodically remove the metal product (reduced form of the metal oxide). When a third reactor is present, the first and third reactors can be co-located.

[0189] As used herein, "reactor" can refer to a single reaction vessel or to reaction zones contained within a reaction vessel. When a single reactor contains multiple reaction zones, the number of zones can be two, three, four, or more.

[0190] The first reactor and the second reactor may be physically contained within a single reactor, such that the first reactor is a first zone and the second reactor is a second zone within the same physical apparatus as the first zone. In these or other embodiments, the second reactor and the third reactor may be physically contained within a single reactor, such that the second reactor is a first zone and the third reactor is a second zone within the same physical apparatus as the first zone (see, for example, FIG. 4). In certain embodiments, the first reactor, second reactor, and third reactor are all physically contained within a single reactor, such that the first reactor is a first zone, the second reactor is a second zone, and the third reactor is a third zone within a common physical apparatus.

[0191] It should also be noted that multiple physical devices can be used in the reactor in series or parallel. For example, the first reactor can be two physical reaction vessels operating in series (sequentially), parallel, or a hybrid thereof.

[0192] Similarly, the second reactor may be two physical reaction vessels operating in series (sequentially), parallel, or a hybrid thereof. Multiple reaction vessels for the second reactor may be advantageous, for example, when it is desired to produce several different types of activated carbon, or when it is desired to produce activated carbon from one vessel but not another. In other words, the second primary reactor may be configured to react the bioreagent with a selected reactant, thereby producing a reducing gas, and the second primary reactor may be configured to continuously, periodically, or eventually remove activated carbon from the second primary reactor. Meanwhile, the auxiliary second reactor may also be configured to react the bioreagent with a selected reactant, thereby producing a reducing gas, but may not be configured, for example, to remove activated carbon from the auxiliary second reactor.

[0193] In some embodiments, the system is co-located at a metal oxide mine.

[0194] In some embodiments, the system is co-located with a metal oxide processing plant, for example, a steel mill, a taconite plant, or a direct reduced iron plant.

[0195] In certain embodiments, the entire system is located at a single site, which may be a greenfield site or an existing site, where the site may include a biomass processing plant, a pyrolysis plant, a coal plant, a metal ore mine, a metal ore processing plant, a gasification plant, a steam reforming plant, or another type of plant.

[0196] In some embodiments, the third reactor is a metal ore furnace or is upstream of the metal ore furnace (or there is a third reactor upstream of the metal ore furnace and a fourth reactor that is a metal ore furnace). The metal ore furnace can be selected from a blast furnace, a direct reduction metal furnace, a top gas recirculation blast furnace, a shaft furnace, a reverberatory 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 hearth furnace, a continuous chain furnace, a pusher furnace, a rotary hearth furnace, a walking beam furnace, an electric arc furnace, an induction furnace, a basic oxygen furnace, a puddle furnace, a Bessemer furnace, or a combination thereof.

[0197] Other variations of the present disclosure include: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a carbon-containing bioreagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the biological reagent with the selected reactant, thereby generating a reducing gas; (e) chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) recovering the metal product comprising the reduced form of the selected metal oxide.

[0198] Yet another variation of the present disclosure is (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a carbon-containing bioreagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the biological reagent with the selected reactant, thereby generating a reducing gas; (e) separating hydrogen from the reducing gas, optionally wherein the hydrogen is separated by one or more separation techniques selected from pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation; (f) recovering the renewable hydrogen product comprising hydrogen.

[0199] Carbon 14 C / 12 Measuring C isotope ratios (in solid carbon or in vapor forms such as CO, CO2, or CH4) is a proven technique. Similar concepts can be applied to hydrogen, 2 H / 1 The H isotope ratio is measured ( 2 H is deuterium, also known as D). Fossil sources tend to be depleted in deuterium compared to biomass. See Schiegl et al., "Deuterium content of organic matter," Earth and Planetary Science Letters, Vol. 7, No. 4, 1970, pp. 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.

[0200] In particular, the natural deuterium content of organically bound hydrogen exhibits 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 even more deuterium depleted relative to plants, and natural gas is even more deuterium depleted relative to the coal or petroleum from which it is derived. In this disclosure, "renewable hydrogen" refers to hydrogen that is available for use in reacting with carbon or CO to form H, regardless of the renewability of the hydrogen contained in the water (HO) reactant. 2 H / 1 It is determined by correlating the H isotope ratio with the reproducibility of the starting feedstock. On average, water has 6,400 hydrogen atoms. 1 It contains approximately one deuterium atom per H atom. The ratio of deuterium atoms to hydrogen atoms in renewable biomass is slightly less than 1 / 6,400, and the ratio of deuterium atoms to hydrogen atoms in non-renewable fossil sources (e.g., 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, and is higher 2 H / 1 The H isotope ratio indicates a greater renewable hydrogen content. 2 H / 1 The H isotope ratio may 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 that of other comparable reducing gas compositions obtained from fossil sources 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 higher by about 1% to about 100% or any number in between, for example, from about 1%, 5%, 10%, 25%, 50%, or 100% or any number in between.

[0201] Renewable hydrogen may be recognized in the marketplace in a variety of ways, such as through renewable energy standards, renewable energy credits, renewable identification numbers, etc. By way of example only, refineries that utilize renewable hydrogen in producing gasoline may receive renewable energy credits for such H content. In metal products such as steel, renewable hydrogen may be utilized during the production of the metal (e.g., reduction of metal ores with H), or renewable hydrogen may be a measurable alloying element in the final product.

[0202] In some embodiments of the present disclosure, the hydrogen product is characterized as at least 50% renewable hydrogen according to hydrogen isotope analysis. In various embodiments, the hydrogen product is characterized as at least 80%, at least 90%, at least 95%, or at least 99% renewable hydrogen. In certain embodiments, the hydrogen product is characterized as fully renewable hydrogen.

[0203] In some hydrogen products, the hydrogen is characterized as fully renewable hydrogen, and any residual carbon contained in the hydrogen product is 14 C / 12 It is essentially fully renewable carbon, as determined from measurements of C isotope ratios.

[0204] The selected reactant in step (d) can be, for example, water, oxygen, or a mixture thereof. The oxygen can be present in a form selected from air, pure oxygen, enriched oxygen, ozone, or a combination thereof.

[0205] In some embodiments, the reducing gas can contain at least 10 mole percent or at least 25 mole percent hydrogen, hi some embodiments, the reducing gas can contain at least 10 mole percent or at least 25 mole percent carbon monoxide.

[0206] In some embodiments, the hydrogen product is produced by a process further comprising increasing the hydrogen content of the reducing gas via a water gas shift reaction.

[0207] In some embodiments, the pyrolysis off-gas is partially oxidized, thereby producing additional reducing gas and heat.

[0208] In various embodiments, the hydrogen is separated via pressure swing adsorption, molecular sieve membrane separation, cryogenic distillation, or a combination thereof.

[0209] The hydrogen product can comprise at least 50 mole percent hydrogen. In some embodiments, the hydrogen product can comprise at least 90 mole percent hydrogen. In various embodiments, the hydrogen product can comprise a range from or between about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or 100 mole percent hydrogen.

[0210] In some hydrogen products, the hydrogen product contains at most about 1 mole percent 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 mole percent nitrogen or any range therebetween. In this disclosure, a "substantially nitrogen-free" hydrogen product means that there is no detectable nitrogen in the product by conventional analytical techniques.

[0211] Some variations provide a reducing gas composition for reducing metal oxides, the reducing gas composition comprising hydrogen that is at least 50% renewable hydrogen according to hydrogen isotope analysis. In various embodiments, the reducing gas composition comprises hydrogen characterized as at least 80%, at least 90%, at least 95%, or at least 99% renewable hydrogen. In certain embodiments, the reducing gas composition comprises hydrogen characterized as fully renewable hydrogen.

[0212] The compositional profile of the reducing gas composition 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, regardless of whether the hydrogen is qualified or characterized as renewable hydrogen. The remainder of the reducing gas composition can include CO, CO, HO, CH, N, or other components.

[0213] Some variations of the present disclosure provide a reducing gas composition for reducing metal oxides, the reducing gas composition comprising a hydrogen isotope 2 H / 1 Contains at least 25 mole % hydrogen that is at least 50% renewable hydrogen according to H analysis.

[0214] In some embodiments, the reducing gas composition comprises at least 50 mole percent hydrogen, at least 75 mole percent hydrogen, or at least 90 mole percent hydrogen. In various embodiments, the reducing gas composition comprises from about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 mole percent hydrogen, or any range therebetween.

[0215] In some reducing gas compositions, hydrogen is a hydrogen isotope 2 H / 1 In some embodiments, the hydrogen is characterized as 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 according to H analysis. 2 H / 1 Characterized as fully (100%) renewable hydrogen according to H analysis.

[0216] The reducing gas composition can further comprise a carbon-containing gas comprising CO, CO, or CH, or the reducing gas composition can further comprise a carbon-containing gas consisting essentially of CO, CO, or CH. 14 C / 12 It may be 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 composition comprises a carbon-containing gas, and the hydrogen isotope is 2 H / 1 It is characterized as at least 90% renewable hydrogen, or essentially fully renewable hydrogen, according to H analysis.

[0217] In some reducing gas compositions, the reducing gas composition further comprises carbon monoxide, the carbon monoxide being 14 C / 12 In some embodiments, the reducing gas composition further comprises carbon monoxide, and the hydrogen is at least 50% renewable, at least 90% renewable, or essentially fully renewable, as determined from measurements of the C isotope ratio. 2 H / 1 In some reducing gas compositions, the molar ratio of hydrogen to carbon monoxide is at least 2.

[0218] In some embodiments, the reducing gas composition includes at most about 1 mol% N, at most about 0.5 mol% N, at most about 0.1 mol% N, or essentially no N. In various embodiments, the reducing gas composition includes at most 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 there is no detectable nitrogen in the reducing gas composition by conventional analytical techniques.

[0219] The process disclosed herein is an environmentally friendly technology with a reduced carbon footprint. When the starting material is biomass, which contains both living and renewable carbon, the carbon obtained by pyrolysis is also living. This can be achieved, for example, by determining the carbon content using ASTM D6866. 14 C / 12 This can be shown from measurements of C isotope ratios. In some embodiments, all of the processed carbon is renewable. In other embodiments, less than all of the carbon is renewable.

[0220] Any biogenic carbon that is oxidized to carbon dioxide creates biogenic CO2. This also reduces the carbon in the produced CO2. 14 C / 12 This can also be shown from measurements of C isotope ratios. This biogenic CO2, derived from the biomass, is returned to the environment to be reabsorbed by the growing biomass via photosynthesis. In this way, net CO2 emissions are significantly reduced. Furthermore, the hydrogen content of the starting biomass substantially reduces the net CO2 emissions of the process. This is because the hydrogen in the biomass becomes H2 in the reducing gas. H2 can cause chemical reduction of metal oxides in much the same way as is caused by CO2, but H2 oxidation creates H2O rather than CO2, which is not considered a problematic greenhouse gas.

[0221] Another reason the disclosed process is environmentally superior to conventional technologies relates to the energy balance. Metal oxide reduction is inherently energy-intensive because the overall chemical reaction is endothermic. Even known approaches of electrochemical conversion, which decompose metal oxides into metals and oxygen, thereby avoiding any direct CO2 production, require large amounts of electricity, which is typically generated from non-renewable sources. Traditional metal ore processing utilizes large amounts of coal to create the necessary heat (from coal combustion) and to provide carbon for the reduction chemical 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.

[0222] 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 amount of net carbon dioxide produced per ton of ore processed. "CO2 equivalent carbon intensity" can also be defined as the net carbon dioxide equivalent produced per ton of ore processed. "Carbon dioxide equivalent" or "CO2e" represents the amount of CO2 that has an equivalent global warming effect. As an example, for metal mining processing, the average is 11.9 kg 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 reduction in carbon intensity or CO2 equivalent carbon intensity 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, resulting in a very low, zero, or even negative effective carbon intensity if there is net carbon sequestration in the final product, such as carbon steel.

[0223] Some variations are based on the recognition that oxygen can be intentionally limited in the combustion of pyrolysis off-gas to produce more CO (rather than CO as in complete combustion), which can then be used as a reducing agent. The production of CO from partial oxidation still provides some heat, but provides less heat compared to conventional complete oxidation to CO. These variations take advantage of the discovery that the heat produced can be sufficient to carry out an endothermic reduction of metal oxides, the reduction chemically utilizing the CO produced from the partial oxidation.

[0224] Based on the above recognition, some variations provide a method for optimizing metal oxide reduction, the method including pyrolyzing biomass to obtain carbon and pyrolysis off-gas, oxidizing the pyrolysis off-gas with intentionally less oxygen than the combustion stoichiometric amount of oxygen, thereby generating heat and reducing gas, and utilizing the heat and reducing gas to reduce the metal oxides.

[0225] A "combustion stoichiometric amount of oxygen" is the amount of oxygen, whether present in air, pure oxygen, or oxygen-enriched air, that is not in stoichiometric excess and that completely oxidizes carbon-containing or hydrogen-containing components to CO or HO, respectively. When pyrolysis off-gas is intentionally oxidized at less than the stoichiometric amount for combustion, the oxygen utilized as a percentage of the combustion stoichiometry of oxygen can be from about 10% to about 99%, from about 25% to about 90%, e.g., from about 40% to about 80%. In various embodiments, this percentage 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 percentages are on a molar basis where the oxygen is in the O form.

[0226] 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 then reacting the carbon monoxide with the metal oxide.

[0227] Reducing gas generation The generation of a reducing gas (also referred to herein as a "bioreductant gas") will now be further described. The conversion of the bio-reagent to a reducing gas occurs in a reactor that may be referred to herein as a second reactor, a gasifier, or a bioreductant formation unit.

[0228] A reactant is used to react with the biological reagent to produce a reducing gas. The reactant can be selected from oxygen, water vapor, or a combination thereof. In some embodiments, oxygen is mixed with water vapor and the resulting mixture is added to a second reactor. Oxygen or oxygen-enriched air can be added to induce exothermic reactions, such as partial or total oxidation of carbon by oxygen, to achieve a more favorable H2 / CO ratio in the reducing gas; (iii) increase the yield of the reducing gas; or (iv) increase the purity of the reducing gas by, for example, reducing the amount of CO2, pyrolysis products, tar, aromatic compounds, or other undesirable products.

[0229] In some embodiments, water vapor is a reactant. Water vapor (i.e., HO in the vapor phase) can be introduced into the second reactor in one or more input streams. Water vapor can include water vapor generated by moisture contained in the bioreagent input, as well as water vapor generated by any chemical reaction that produces water.

[0230] All references herein to "ratios" of chemical species are references to molar ratios unless otherwise indicated. For example, a H2 / CO2 ratio of 1 means 1 mole of hydrogen per mole of carbon dioxide.

[0231] Steam reforming, partial oxidation, water-gas shift (WGS), or combustion reactions can occur when oxygen or steam is added. Exemplary reactions can be seen, for example, in the reaction of cellulose repeating units (CH) found in cellulosic feedstocks. 10 O5) is shown below. Similar reactions can occur using any carbon-containing raw material. Steam reforming C6H 10 O5+H2O→6CO+6H2 Partial oxidation C6H 10 O5 + 1 / 2O2 → 6CO + 5H2 Water-gas shift CO+H2O⇔H2+CO2 Complete combustion C6H 10 O5 + 6O2 → 6CO2 + 5H2O

[0232] The second reactor can be any reactor capable of causing a chemical reaction that produces a reducing gas. Conventional steam reformers known in the art can be used, with or without a catalyst. Other possibilities include autothermal reformers, partial oxidation reactors, and multi-stage reactors that combine several reaction mechanisms (e.g., partial oxidation followed by water-gas shift). The reactor configuration can be a fixed bed, a fluidized bed, multiple microchannels, or some other configuration.

[0233] In some embodiments, the total amount of steam reactant is at least about 0.1 moles of steam per mole of carbon in the feedstock. In various embodiments, at least about 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, or more moles of steam per mole of carbon are added or present. In some embodiments, between about 1.5 and 3.0 moles of steam per mole of carbon are added or present.

[0234] The amount of steam added to the second reactor can vary depending on factors such as the conditions of the pyrolysis reactor. If pyrolysis produces a carbon-enriched solid material, typically more steam (or more oxygen) is used to add the necessary H and O atoms to the available C, thereby producing CO and H. From a system-wide perspective, the moisture contained in the feed material can be considered when determining how much additional water (steam) to add in the process.

[0235] Exemplary ratios of oxygen to water vapor (O2 / H2O) in the second reactor are equal to or at most about any of 2, 1.5, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01, or less. When the ratio of O2 / H2O is at least about 1, the combustion reaction begins to dominate over partial oxidation, which can result in an undesirably low CO / CO2 ratio.

[0236] In some embodiments, oxygen without water vapor is used as a reactant. The oxygen can be added in substantially pure form or, optionally, can be supplied to the process via the addition of oxygen-enriched air. In some embodiments, air that is not oxygen-enriched is added. In other embodiments, enriched air from an off-spec or recycle stream can be used, which can be, for example, a stream from a nearby air separation plant. In some embodiments, using enriched air with a reduced amount of N (i.e., at most about 79% by volume) results in less N in the resulting reducing gas. Removal of N can be expensive, and therefore, a method of producing a reducing gas with little or no N can be desirable.

[0237] In some embodiments, the presence of oxygen alters the ratio of H2 / CO in the reducing gas compared to the ratio produced by the same method in the absence of oxygen. The H2 / CO ratio of the reducing gas can be from about 0.5 to about 2.0, e.g., from about 0.75 to 1.25, from about 1 to 1.5, or from about 1.5 to 2.0. As will be appreciated, increased water-gas shift (due to higher steam addition rates) produces higher H2 / CO ratios, e.g., at least 2.0, 3.0, 4.0, 5.0, or even higher, which may be desirable for certain applications involving hydrogen production.

[0238] A catalyst can be utilized in the second reactor. Catalysts can include, but are not limited to, alkali metal salts, alkaline earth metal oxides and salts, inorganic materials in coal or ash, transition metals and their oxides and salts, and eutectic salt mixtures. Specific examples of catalysts include, but are not limited to, potassium hydroxide, potassium carbonate, lithium hydroxide, lithium carbonate, cesium hydroxide, nickel oxide, nickel-substituted synthetic mica montmorillonite (NiSMM), molybdenum on NiSMM, iron hydroxide oxides, iron nitrate salts, iron-calcium impregnated salts, nickel uranyl oxide, sodium fluoride, and cryolite.

[0239] Other exemplary catalysts include, but are not limited to, nickel, nickel oxide, rhodium, ruthenium, iridium, palladium, and platinum. Such catalysts may be coated or deposited on one or more support materials, such as, for example, gamma-alumina (optionally doped with a stabilizing element such as magnesium, lanthanum, or barium).

[0240] Prior to being added to the system, any catalyst can be pretreated or activated using known techniques to affect total surface area, active surface area, site density, catalyst stability, catalyst life, catalyst composition, surface roughness, surface dispersion, porosity, density, or thermal diffusivity. Catalyst pretreatment includes, but is not limited to, calcination, washcoat addition, particle size reduction, and surface activation by thermal or chemical means.

[0241] The catalyst can be added by first dissolving or slurrying the catalyst in a solvent, such as water or any hydrocarbon that can be gasified or reformed. In some embodiments, the catalyst is added by directly injecting such a slurry into a vessel. In some embodiments, the catalyst is added to the steam, and the steam / catalyst mixture is added to the system. In these embodiments, the added catalyst can be at or near its equilibrium solubility in the steam, or can be introduced as particles entrained in the steam and thereby introduced into the system.

[0242] Materials can generally be conveyed into and out of the second reactor by single screws, twin screws, rams, etc. Materials can be mechanically conveyed by physical force (metal contact), pressure-driven flow, pneumatically-driven flow, centrifugal flow, gravity flow, fluidized flow, or some other known means of moving solid and gas phases. A fixed bed of bioreagent pellets can be utilized in the second reactor, particularly in embodiments using a metal oxide bed disposed above a carbon bed (e.g., FIG. 4), thereby producing mechanically robust activated carbon pellets.

[0243] In some embodiments, the second reactor employs gasification of the bioreagent, thereby producing a reducing gas. Gasification is performed at high temperatures, such as at least about 600°C to as high as about 1100°C. Less reactive bioreagents use higher operating temperatures. The amount of reactant (e.g., air, oxygen, enriched air, or an oxygen-steam mixture) introduced can be the primary factor controlling the gasification temperature. Operating pressures from atmospheric pressure up to about 50 bar have been used in biomass gasification. Gasifiers also use reactants, typically air, high-purity oxygen, steam, or some mixture of these gases.

[0244] Gasifiers can be distinguished based on the means of supporting solids within the vessel, the direction of flow of both solids and gas, and the method of providing heat to the reactor. Whether the gasifier operates at near atmospheric or elevated pressure, and whether the gasifier is air-blown or oxygen-blown, are also distinguishing features. Common classifications are fixed-bed upflow, fixed-bed downflow, bubbling fluidized bed, and circulating fluidized bed.

[0245] Fixed bed gasifiers generally cannot handle fibrous herbaceous feedstocks such as wheat straw, corn stover, or yard waste. However, in the disclosed process, the biomass is first pyrolyzed into bioreagents, which are then gasified. The bioreagents can be gasified using a fixed bed gasifier.

[0246] Circulating fluidized bed gasification technology is available from Lurgi and Foster Wheeler and represents the majority of existing gasification technologies utilized for biomass and other wastes. Bubbling fluidized bed gasification (e.g., U-GAS® technology) is also in commercial use.

[0247] Directly heated gasifiers perform endothermic and exothermic gasification reactions in a single reaction vessel, requiring no additional heating. In contrast, indirectly heated gasifiers use an external heat source. Indirectly heated gasifiers typically use two vessels. The first vessel gasifies the feed with steam (an endothermic process). Heat is provided by a circulating heat transfer medium, usually 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.

[0248] The bioreagents can be introduced into the gasifier as a "dry feed" (optionally containing moisture but no free liquid phase) or as a slurry or suspension in water. Dry-feed gasifiers can allow for high per-pass carbon conversion to reducing gas and good energy efficiency. In dry-feed gasifiers, the energy released by the gasification reaction can cause the gasifier to reach extremely high temperatures. This problem can be solved by using a wet-wall design.

[0249] In some embodiments, the feed to the gasifier is a bioreagent with a high hydrogen content, and the resulting reducing gas is relatively enriched in hydrogen and has a high H2 / CO ratio, e.g., H2 / CO > 1.5 or greater.

[0250] In some embodiments, the feed to the gasifier is a bioreagent with low hydrogen content. The resulting reducing gas is expected to have a relatively low H2 / CO ratio. In downstream processes using H2 / CO>1, it may be desirable to inject water or steam into the gasifier to 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 via steam reforming chemistry. In steam reforming, H2O reacts with carbon or hydrocarbons such as tar or benzene / toluene / xylene to produce reducing gas and lower the adiabatic gasification temperature.

[0251] In certain variations, the gasifier is a fluidized bed gasifier, such as a bubbling fluidized gasification reactor. Fluidization results in a substantially uniform temperature within the gasifier bed. Fluidized bed materials, such as alumina sand or silica sand, can reduce potential attrition problems. The gasifier temperature can be adjusted to a temperature low enough so that ash particles do not begin to change from a solid to a molten form, which can cause agglomeration and loss of fluidization within the gasifier.

[0252] If a fluidized bed gasifier is used, the total flow rate of all components should ensure that the gasifier bed is fluidized. The total gas flow rate and bed diameter establish the gas velocity through the gasifier. The correct velocity must be maintained to ensure proper fluidization.

[0253] In variations, the gasifier type may be entrained flow slagging, entrained flow non-slagging, transport, bubbling fluidized bed, circulating fluidized bed, or fixed bed. Some embodiments use a gasification catalyst.

[0254] A circulating fluidized bed gasifier can be used, in which gas, sand, and feedstock move together. Exemplary transport gases include recycled product gas, combustion gas, or recycled gas. The high heat transfer rate from the sand ensures rapid heating of the feedstock, and ablation is expected to be stronger 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.

[0255] In some embodiments where a countercurrent fixed-bed gasifier is used, the reactor contains a fixed bed of feedstock through which a gasifying agent (such as steam, oxygen, or recycle gas) flows in a countercurrent configuration. Ash is removed dry or as a slag.

[0256] In some embodiments where a co-current fixed-bed gasifier is used, 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.

[0257] In some embodiments where a fluidized bed reactor is used as the second reactor, the feedstock is fluidized in recycle gas, oxygen, air, or steam. Ash can be removed dry or as heavy agglomerates that are defluidized. Solids recycle or subsequent combustion can be used to increase conversion. Fluidized bed reactors are useful for feedstocks that form highly corrosive ash that would damage the walls of a slagging reactor.

[0258] In some embodiments where an entrained flow gasifier is used, the bio-reagent is gasified in co-current with oxygen, air, or recycle gas. The gasification reaction occurs in a dense cloud of very fine particles. High temperatures can be used, which reduces the amount of tar and methane in the reducing gas.

[0259] Entrained flow reactors remove most of the ash as slag because the operating temperature can be well above the ash melting temperature. A smaller portion of the ash is produced as very fine dry fly ash or as fly ash slurry. Some entrained bed reactors have internal water- or steam-cooled walls that are covered with partially solidified slag.

[0260] The gasifier chamber can be designed to keep the carryover of solids downstream operations at a level suitable for heat recovery by appropriate configuration of the freeboard or use of internal cyclones. Unreacted bioreagents can be drawn off from the bottom of the gasifier chamber, cooled, and recovered.

[0261] The gasifier may include one or more catalysts, such as catalysts effective for partial oxidation of carbon-containing species, reverse water gas shift, or dry (CO2) reforming.

[0262] In some embodiments, a bubbling fluidized bed devolatilization reactor is utilized as the second reactor. The reactor is heated, at least in part, by a hot recycle gas stream to about 600°C, which is below the expected slagging temperature of the biomass. Steam, oxygen, or air can also be introduced into the second reactor.

[0263] The second reactor can be designed to keep solids carryover at a level suitable for downstream heat recovery by appropriate configuration of the freeboard or use of internal cyclones. Unreacted char can be withdrawn from the bottom of the devolatilization chamber, cooled, and then fed to a utility boiler to recover the remaining heating value of this stream.

[0264] When a fluidized-bed gasifier is used as the second reactor, the feedstock can be introduced into a bed of hot sand fluidized by a gas, such as recycle gas. References to "sand" herein also include similar substantially inert materials, such as glass particles, recovered ash particles, etc. The high heat transfer rate from the fluidized sand can result in rapid heating of the feedstock. Some abrasion due to friction with the sand particles may occur. Heat can be provided by heat exchanger tubes through which hot combustion gases flow.

[0265] A circulating fluidized bed reactor, in which gas, sand, and feedstock move together, can be used as the second reactor. Exemplary transport gases include recycled product gas, combustion gas, or recycled gas. The high heat transfer rate from the sand ensures rapid heating of the feedstock, and ablation is expected to be stronger 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.

[0266] In some embodiments where a countercurrent fixed-bed reactor is used as the devolatilization unit, the reactor contains a fixed bed of feedstock through which a gasifying agent (such as steam, oxygen, or recycle gas) flows in a countercurrent configuration. Ash is removed dry or as a slag.

[0267] In some embodiments, a cocurrent fixed-bed reactor is used as the devolatilization unit. The reactor is similar to a countercurrent reactor, but the gasifying gas flows in a cocurrent 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 leaves 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. In this configuration, tar levels are expected to be lower than when using a countercurrent reactor, since the tar passes through the hot carbon bed.

[0268] In some embodiments where a fluidized bed reactor is used as the devolatilization unit, the feedstock is fluidized in recycle gas, oxygen, air, or steam. Ash is removed dry or as heavy agglomerates that are defluidized. Solids recycle or subsequent combustion can be used to increase conversion.

[0269] To improve heat and mass transfer, water can be introduced into the second reactor using a nozzle, which is generally a mechanical device designed to control the direction or characteristics of a fluid flow as it enters a closed chamber or pipe through an orifice. The nozzle can reduce the droplet size, thereby producing a fine spray of water. The nozzle can be selected from atomizing nozzles (similar to fuel injectors), swirl nozzles that spray liquid tangentially, and the like.

[0270] Water sources can include, for example, process condensate, other recycled water, wastewater, make-up water, boiler feedwater, direct piping from city water. The water can optionally first be washed, purified, treated, ionized, distilled, etc. When several water sources are used, various volume ratios of the water sources are possible. In some embodiments, the water for the second reactor is wastewater.

[0271] In some variations, the reducing gas from the second reactor is filtered, purified, or otherwise conditioned before being converted to another product. For example, the cooled reducing gas can be introduced into a conditioning unit where benzene, toluene, ethylbenzene, xylenes, sulfur compounds, nitrogen, metals, or other impurities are optionally removed from the reducing gas.

[0272] Some embodiments of the present disclosure include a reduction gas purification unit downstream of the second reactor. The reduction gas purification unit is not particularly limited in its design. Exemplary reduction gas purification units include cyclones, centrifuges, filters, membranes, solvent-based systems, and other means for removing particulate matter or other specific contaminants.

[0273] In some embodiments, an acid gas removal unit is included downstream of the second reactor. 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.

[0274] Examples of acid gas removal steps include removing CO with one or more solvents for CO or removing CO with 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 (such as the Selexol® process) and chilled methanol (such as the Rectisol® process).

[0275] The reducing gas produced as described in accordance with the present disclosure can be utilized in many ways. The reducing gas can generally be 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 by Fischer-Tropsch chemistry to linear or branched C5-C6 hydrocarbons. 15 It can be converted into hydrocarbons, diesel fuel, gasoline, wax, or olefins, mixed alcohols by various catalysts, isobutane by isosynthesis, ammonia by hydrogen production followed by the Haber process, aldehydes and alcohols by oxosynthesis, and many derivatives of methanol, including dimethyl ether, acetic acid, ethylene, propylene, and formaldehyde, by various processes. The reducing gas can also be converted into 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.

[0276] Activated carbon recovery Next, the recovery of activated carbon will be further explained.

[0277] In some embodiments, step (f) is performed intentionally or incidentally to produce an activated carbon co-product. When step (f) is performed, step (e) may or may not be performed.

[0278] In certain embodiments, steps (e) and (f) are carried out in an integrated reactor having separate reaction zones for in situ generation of a reducing gas and then utilizing that reducing gas, or at least a portion thereof, to reduce metal oxides to metal or less reduced metal oxides.

[0279] When step (f) is used, at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% by weight of the bioreagent produced in step (b) can be recovered as activated carbon. The process can be adjusted so that more or less activated carbon can be produced compared to the carbon (typically as carbon oxides) that is directed to the reducing gas.

[0280] In certain embodiments, the fixed carbon in the bio-reagent can be used primarily to produce activated carbon, and the volatile carbon in the bio-reagent 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 in the bio-reagent produced in step (b) can be recovered as activated carbon in step (f), while, for example, at least 50 wt.%, at least 90 wt.%, or essentially all of the volatile carbon in the bio-reagent produced in step (b) can be directed to a reducing gas (e.g., via a steam reforming reaction of the volatile carbon to CO).

[0281] When produced, the activated carbon can be characterized, for example, by an iodine number of at least about 500, 750, 800, 1000, 1500, or 2000. 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 It is characterized as a (fully) renewable activated carbon, as determined from measurements of the C isotope ratio.

[0282] In some systems, the second reactor is configured to continuously or periodically remove the activated carbon from the second reactor, such as via a screw conveyor to remove carbon pellets from the reactor. In these or other embodiments, the second reactor is configured to eventually remove the activated carbon from the second reactor (i.e., at the end of the reaction time period), such as via a screw conveyor or by opening the reactor and recovering the activated carbon.

[0283] In some embodiments, the second reactor is configured to optimize the production of a different type of activated carbon. For example, reaction conditions (e.g., time, temperature, and steam concentration) can be selected for an activated carbon product with specific attributes, such as iodine value. Different reaction conditions can be selected for a different activated carbon product, such as one with a higher iodine value. The second reactor can operate in a campaign mode to produce one product and then switch to another mode for a different product. The first product can be removed continuously or periodically during the first campaign, or it can be removed before switching the reaction conditions in the second reactor. In general, the second reactor can be optimized for the production of different amounts and characteristics of activated carbon and different amounts and qualities of reducing gas.

[0284] If activated carbon is desired, a third reactor may or may not be present. In some embodiments, both activated carbon and metal products are produced, as shown in Figure 3. In certain embodiments, an integrated reactor is used for both activated carbon production and reduction of metal oxides to metal products.

[0285] The activated carbon can be characterized, for example, by an iodine number of at least about 500, 750, 1000, 1500, or 2000. 14 C / 12 In some embodiments, the activated carbon may be characterized by a renewable carbon content of at least 90% as determined from C isotope ratio measurements. 14 C / 12It is characterized as a (fully) renewable activated carbon, as determined from measurements of the C isotope ratio.

[0286] The activated carbon produced by the processes disclosed herein can be used in a number of ways.

[0287] 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 steam waste streams to reduce air emissions. In some embodiments, activated carbon is utilized as a soil amendment to aid in the generation of new biomass, which may be the same type of biomass utilized on-site as local feedstock.

[0288] Activated carbon prepared according to the processes disclosed herein can have the same or better properties as 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 control pollutants as well as or better than conventional activated carbon products. In some embodiments, the activated carbon has inert material (e.g., ash) levels comparable to, equal to, or less 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 less 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 pore sizes associated with conventional activated carbon products. In some embodiments, the activated carbon has particle abrasion resistance values ​​comparable to, substantially similar to, or the same as particle abrasion resistance values ​​associated with conventional activated carbon products. In some embodiments, the activated carbon has hardness values ​​comparable to, substantially similar to, or the same as hardness values ​​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 bulk density values ​​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 adsorption capacities associated with conventional activated carbon products.

[0289] Prior to suitability or actual use in any product application, the disclosed activated carbons can be analyzed, measured, and optionally modified (such as by additives) in a variety of ways. Some potentially important properties include density, particle size, surface area, microporosity, absorption, adsorption, binding capacity, reactivity, desulfurization activity, basicity, hardness, and iodine number.

[0290] Activated carbon is used commercially in a wide 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, key product attributes can include particle size, shape, composition, surface area, pore volume, pore size, particle size distribution, carbon surface and internal chemistry, particle attrition resistance, hardness, bulk density, and adsorption capacity.

[0291] The bulk density of the biogenic activated carbon can be from about 50 g / liter to about 650 g / liter.

[0292] The surface area of ​​biogenic 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.

[0293] The pore size distribution can be important in determining the ultimate performance of the activated carbon. Pore size measurements can include micropore content, mesopore content, and macropore content.

[0294] Iodine number is a parameter used to characterize activated carbon performance. Iodine number measures the degree of activation of the carbon and is a measure of micropore (e.g., 0-20 Å) content. This is an important measurement for 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.

[0295] 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.

[0296] Another pore-related measurement is the 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 100, 150, 200, 250, 300, 350, and 400. The units of Molasses Number are milligrams of molasses per gram of carbon.

[0297] 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%.

[0298] Hardness, or attrition number, 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 result in excessive equipment wear. Exemplary attrition numbers measured according to ASTM D3802 range from about 1% to greater than about 99%, e.g., 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%.

[0299] In some embodiments, an optimal range of hardness 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 optimum is possible in some embodiments of the present disclosure through the selection of feedstocks and processing conditions. In some embodiments where downstream uses can handle high hardness, the processes of the present disclosure can operate to increase or maximize hardness to produce a biogenic activated carbon product having an attrition number of about 75%, about 80%, about 85%, about 90%, about 95%, about 96%, about 97%, about 98%, about 99%, or at least about 99%.

[0300] The biogenic activated carbon provided by the present disclosure has a wide range of commercial applications. For example, but not by way of limitation, the biogenic activated carbon can be utilized in 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, tanks and process vents, pumps, blowers, filters, pre-filters, mist filters, piping, piping modules, adsorber, absorbers, and columns.

[0301] In one embodiment, a method of using activated carbon to reduce emissions includes: (a) providing activated carbon particles comprising the biogenic activated carbon composition recovered from the second reactor disclosed herein; (b) providing a gas-phase effluent stream containing the selected contaminant; (c) providing an additive selected to assist in the removal of selected contaminants 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 within 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.

[0302] The additive for the biogenic activated carbon composition may be provided as part of the activated carbon particles. Alternatively or additionally, the additive may 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 for removal of selected pollutants are also possible.

[0303] The selected contaminant (in the gas-phase effluent stream) can be 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 (such as a VOC), or a non-condensable gas. In some embodiments, the biogenic activated carbon product adsorbs, absorbs, or chemisorbs the selected contaminant in greater amounts than a comparable 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 (such as 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% hydrogen by weight or at least about 10% oxygen by weight.

[0304] Hazardous air pollutants are pollutants that cause or may cause cancer or other serious health effects (e.g., reproductive effects or birth defects, or adverse environmental and ecological effects). Section 112 of the Clean Air Act, as amended, is incorporated herein by reference in its entirety. Pursuant to Section 112 of the Clean Air Act, the United States Environmental Protection Agency (EPA) is mandated to control 189 hazardous air pollutants. Any current or future compound classified by the EPA as a hazardous air pollutant is included in the possible selected pollutants in this context.

[0305] Volatile organic compounds (some of which are also hazardous air pollutants) are organic chemicals that have high vapor pressures at normal room temperature. Examples include short-chain alkanes, olefins, alcohols, ketones, and aldehydes. Many volatile organic compounds are hazardous to human health or harmful to the environment. The EPA regulates volatile organic compounds in air, water, and land. The EPA's definition of a volatile organic compound is set forth in 40 CFR Section 51.100, which is incorporated herein by reference in its entirety.

[0306] Non-condensable gases are gases that do not condense under normal room temperature conditions and may 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.

[0307] The disclosed activated carbon particles can remove multiple contaminants. In some embodiments, the contaminant-adsorbed carbon particles include at least two contaminants, at least three contaminants, or more. The activated carbons disclosed herein can enable the control of multiple contaminants as well as the control of specific target contaminants (e.g., selenium).

[0308] In some embodiments, the pollutant-adsorbed carbon particles are treated to regenerate the activated carbon particles. In some embodiments, the method includes thermally oxidizing the pollutant-adsorbed carbon particles. The pollutant-adsorbed carbon particles, or a regenerated form thereof, can be combusted to provide energy.

[0309] 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, fluorite, fluorospar, 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.

[0310] In some embodiments, the gas phase effluent stream is derived from metal processing, such as the processing of high sulfur-containing metal ores.

[0311] In an exemplary embodiment for mercury control, activated carbon can be injected (e.g., into piping) 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 located 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 (unless this is a new site) and whether additional downstream particulate matter control equipment is being modified.

[0312] For boilers currently equipped with particulate matter control devices, implementing biogenic activated carbon injection for mercury control 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 fields of the electrostatic precipitator. The inclusion of iron or iron-containing compounds can dramatically improve the performance of electrostatic precipitators for mercury control. Furthermore, the inclusion of iron or iron-containing compounds can significantly change end-of-life options by allowing the separation of spent activated carbon solids from other ash.

[0313] In some embodiments, the powdered activated carbon injection approach can be utilized in combination with an existing SO2 control device. The activated carbon can be injected before the SO2 control device or after the SO2 control device, depending on the availability of a means to collect the activated carbon sorbent downstream of the injection point.

[0314] In some embodiments, the same physical material can be used in multiple processes, either in an integrated manner or sequentially. Thus, for example, activated carbon can be introduced at the end of its useful life as a performance material into a combustion process for its energy value, or into a metal manufacturing process, etc., that uses carbon but does not require the properties of activated carbon.

[0315] The biogenic activated carbon and 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 that has (or can be adjusted to have) an amount of liquid state present.

[0316] In one embodiment, the present disclosure provides a method of using activated carbon to purify a liquid, comprising: (a) providing activated carbon particles recovered from the second reactor; (b) providing a liquid containing the selected contaminant; (c) providing an additive selected to assist in the removal of selected contaminants 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 the contaminant-adsorbing carbon particles and the contaminant-reducing liquid.

[0317] The additive may be provided as part of the activated carbon particles, or the additive may be introduced directly into the liquid. In some embodiments, the additive is introduced both as part of the activated carbon particles and directly into the liquid.

[0318] 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, fluorite, fluorospar, 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.

[0319] In some embodiments, the selected contaminant (in the liquid being 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 (such as a VOC), a halogen, a biological compound, a pesticide, or a herbicide. The contaminant-adsorbed carbon particles can include two, three, or more contaminants. In some embodiments, the activated carbon product adsorbs, absorbs, or chemisorbs the selected contaminant in greater amounts than a comparable 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 (such as a VOC), a non-condensable gas, or any combination thereof. In some embodiments, the selected contaminant includes mercury. In some embodiments, the selected contaminant includes one or more VOCs. In some embodiments, the biogenic activated carbon includes at least about 1% hydrogen by weight or at least about 10% oxygen by weight.

[0320] The liquid to be treated may be aqueous, but 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 solution or in a moving bed.

[0321] In one embodiment, the present disclosure provides a method for removing sulfur-containing contaminants from a liquid using a biogenic activated carbon composition, comprising: (a) providing activated carbon particles recovered from a second 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; and (d) contacting the liquid with the activated carbon particles and the additive, thereby adsorbing or absorbing the sulfur-containing contaminants onto or into the activated carbon particles.

[0322] 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, persulfuranes, or combinations, salts, or derivatives thereof. For example, the sulfur-containing contaminant can be a sulfate in anionic or salt form.

[0323] The liquid may 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 produce sulfur-containing contaminants in the wastewater. The water may also be (or a portion thereof) of a natural body of water such as a lake, river, or stream.

[0324] In one embodiment, the present disclosure provides a process for reducing the concentration of sulfate in water, comprising: (a) providing activated carbon particles recovered from a second reactor as disclosed herein; (b) providing a volume or flow of sulfate-containing water; (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 adsorbing or absorbing the sulfate onto or into the activated carbon particles.

[0325] In some embodiments, sulfate is reduced to a concentration of about 50 mg / L or less in water, such as 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.

[0326] The water can be derived from part or all of a wastewater stream. Exemplary wastewater streams may be associated with 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 may be a natural body of water, such as a lake, river, or stream. In some embodiments, the process is carried out continuously. In other embodiments, the process is carried out in batches.

[0327] When water is treated with activated carbon, it can be by filtering the water, by permeating the water, or by adding activated carbon particles directly to the water (with sedimentation, clarification, etc.). When permeation is used, activated carbon can be used in several ways within the permeation device or to support the permeation device. In some embodiments, activated carbon particles and additives are introduced directly 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.

[0328] The present disclosure also provides a method of using a biogenic activated carbon composition for removing sulfur-containing contaminants from a gas phase, comprising: (a) providing activated carbon particles recovered from a second reactor as disclosed herein; (b) providing a gas-phase effluent stream containing 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 activated carbon particles and an additive into the gas-phase exhaust stream, thereby adsorbing or absorbing sulfur-containing contaminants onto the activated carbon particles; (e) separating the activated carbon particles from the gas-phase effluent stream.

[0329] 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 halides, thioketone, thioaldehyde, sulfur oxide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, sulfenic acid, sulfonium, oxosulfonium, sulfurane, persulfuranes, or combinations, salts, or derivatives thereof.

[0330] Generally speaking, the disclosed activated carbons can be used in any application where conventional activated carbons can be used. In some embodiments, the activated carbons are used as a total (i.e., 100%) replacement for conventional activated carbons. In some embodiments, the activated carbons comprise essentially all or substantially all of the activated carbon used in a particular application. In some embodiments, the activated carbons comprise from about 1% to about 100% biogenic activated carbon.

[0331] For example, but not by way of limitation, activated carbon can be used in filters, either alone or in combination with conventional activated carbon products. In some embodiments, a packed bed or column comprises the disclosed activated carbon. In such embodiments, the biogenic activated carbon has size characteristics suitable for the particular packed bed or column. Injection of biogenic activated carbon into gas streams can be useful for controlling pollutant emissions in gas or liquid streams from coal-fired power plants, biomass-fired power plants, metal processing plants, crude oil refineries, chemical plants, polymer plants, pulp and paper plants, cement plants, waste incinerators, food processing plants, gasification plants, and syngas plants.

[0332] Metal Oxide Reduction Furnace Various embodiments using a metal ore furnace or a chemical reduction furnace will now be further described.

[0333] The metal ore furnace or chemical reduction furnace may be a blast furnace, direct reduction metal furnace, top gas recirculation blast furnace, shaft furnace, reverberatory furnace, crucible furnace, silencer furnace, retort furnace, flash furnace, Tecnored furnace, Ausmelt furnace, ISASMELT furnace, Puddle furnace, bogie hearth furnace, continuous chain furnace, pusher furnace, rotary hearth furnace, walking beam furnace, electric arc furnace, induction furnace, basic oxygen furnace, Puddle furnace, Bessemer furnace, or combinations thereof.

[0334] 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 cocurrent or countercurrent. 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 of temperature, pressure, and residence time.

[0335] 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 in smelting iron ore to produce pig iron, an intermediate material used in the production of commercial iron and steel. Blast furnaces are also used in conjunction with sinter plants, for example, in base metal smelting.

[0336] The term "blast" refers to the forced or supplied combustion air above atmospheric pressure. In a blast furnace, metal ore, carbon (e.g., in this disclosure, bioreagent or its derivatives), and usually flux (e.g., limestone) are continuously supplied through the top of the furnace, while a hot blast of air (optionally with oxygen enrichment) is blown into the lower part of the furnace through a series of pipes called tuyere. Chemical reduction reactions occur throughout the furnace as the material falls downward. The end products are typically molten metal and slag phases removed from the bottom, and waste gases (reduction off-gases) exiting the top of the furnace. The downward flow of metal ore along with the flux in countercurrent contact with the upward flow of hot CO2-enriched gas allows for efficient chemical reactions that reduce the metal ore to metal.

[0337] Air furnaces (such as reverberatory furnaces) are usually naturally aspirated by convection of hot gases in the chimney flue. By this broad definition, bloomery furnaces for iron, blowhouses for tin, and smelting plants for lead are classified as blast furnaces.

[0338] Blast furnaces remain an important part of modern iron production. Modern furnaces are highly efficient and include a cowper stove, which preheats the incoming blast air with waste heat from the flue gases, and a recovery system, which extracts heat from the hot gases exiting the furnace. Blast furnaces are built in the form of tall structures lined with refractory bricks and contoured to expand as the feed material heats during its descent, then reduce in size as melting begins to occur.

[0339] In some iron production embodiments, 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 exit the furnace throat, while a bleeder valve can protect the top of the furnace from sudden gas pressure surges. Coarse particles in the exhaust gas can settle and be disposed of, while the gas can flow through a venturi scrubber, electrostatic precipitator, or gas cooler to reduce the temperature of the purified gas. A casting chamber at the bottom of the furnace houses equipment for casting liquid iron and slag. A taphole can be drilled with a refractory plug so that the liquid iron and slag flow down a launder through the opening, separating the iron and slag. Once the pig iron and slag are tapped, the taphole can be plugged with fireclay. A nozzle called a tuyere is used to supply hot air to increase the efficiency of the blast furnace. Hot air is directed into the furnace through cooled tuyeres near the base. Hot air temperatures can be, for example, about 900°C to 1300°C (air temperature). Temperatures within the furnace can be at least about 2000°C or higher. Other carbonaceous materials or oxygen can also be injected into the furnace at the tuyeres level to combine with the carbon (from the bioreagents) to release additional energy and increase the percentage of reducing gas present, which increases productivity.

[0340] Blast furnaces operate on the principle of chemical reduction, in which carbon monoxide, which has a stronger affinity for oxygen in metal ores (e.g., iron ore) than the corresponding metals, reduces the metals to their elemental forms. Blast furnaces differ from bloomery and reverberatory furnaces in that, in a blast furnace, the flue gases come into direct contact with the ore and metal, diffusing the carbon monoxide into the ore and reducing the metal oxides to elemental metal mixed with carbon. Blast furnaces typically operate as a continuous countercurrent exchange process.

[0341] Silica is typically removed from the pig iron. It reacts with calcium oxide to form silicates, which float to the surface of the molten pig iron as slag. The downwardly moving column of metal ores, fluxes, carbon, and reaction products must be porous enough to allow flue gases to pass through. This requires the bioreagent carbon to be particles large enough to be permeable. Therefore, the bioreagent (which may contain additives) must be strong enough to not be crushed by the weight of the material above it. In addition to the carbon's physical strength, it can also be low in sulfur, phosphorus, and ash.

[0342] Many chemical reactions occur in a blast furnace. Chemical reactions can be understood with reference to hematite (Fe2O3) as the starting metal oxide. This form of iron oxide is common in iron ore processing, either in the initial feedstock or as produced in the blast furnace. Other forms of iron ore (e.g., taconite) have varying concentrations of different iron oxides (Fe3O4, Fe2O3, FeO, etc.).

[0343] The main overall chemical reactions that produce molten iron in a blast furnace are as follows: Fe2O3+3CO→2Fe+3CO2 This is an endothermic reaction that occurs in a number of steps, the first of which is that preheated blast air blown into the furnace reacts with carbon (e.g., from the bioreagent) to produce carbon monoxide and heat. 2C+O2→2CO Hot carbon monoxide is a reducing agent for iron ore, reacting with iron oxide to produce molten iron and carbon dioxide. Depending on the temperature in different parts of the furnace (typically highest at the bottom), the iron is reduced in several steps. At the top, where temperatures typically range from 200 to 700°C, the iron oxide is partially reduced to iron (II, III) oxide, Fe3O4. 3Fe2O3+CO → 2Fe3O4+CO2 Further down the furnace, at a temperature of about 850°C, the iron (II, III) is further reduced to iron (II) oxide, FeO: Fe3O4+CO→3FeO+CO2 Hot carbon dioxide, unreacted carbon monoxide, and nitrogen from the air pass upward through the furnace as fresh feed material moves downward into the reaction zone. As the material moves downward, countercurrent gas preheats the feed charge and decomposes limestone (if used) into calcium oxide and carbon dioxide. CaCO3 → CaO + CO2 The calcium oxide formed by decomposition reacts with various acidic impurities (especially silica) contained in the iron to form a slag which is mainly calcium silicate, CaSiO3. SiO2 + CaO → CaSiO3 As the FeO moves into the higher temperature region up to the 1200°C range, the FeO is further reduced to iron metal, again using carbon monoxide as a reactant. FeO+CO→Fe+CO2 The carbon dioxide formed in this process can be converted back to carbon monoxide by reacting it with carbon via the reverse Boudouid reaction. C+CO2→2CO

[0344] It is important to note that in the chemical reactions shown above, the reducing gas may 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 may include both hydrogen and carbon monoxide, both of which function to chemically reduce metal oxides.

[0345] 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 may be available in the bio-reagent fed to the blast furnace if the bio-reagent contains volatile carbon (e.g., heavy tar components) associated with hydrogen. The hydrogen can drive additional reduction reactions similar to those described above, but replacing CO with H2. 3Fe2O3+H2→2Fe3O4+H2O Fe3O4+4H2→3Fe+4H2O These reactions occur in parallel with reduction reactions with CO. Hydrogen can also react with carbon dioxide in the reverse water gas shift reaction to produce more CO. In certain embodiments, a reducing gas consisting essentially of hydrogen is fed to the blast furnace.

[0346] The "pig iron" produced by a blast furnace typically has a relatively high carbon content, about 3-6% by weight. It can be used to make cast iron. The pig iron produced by a blast furnace usually undergoes further processing to reduce the carbon and sulfur content and to produce the various grades of steel used commercially. In a further process step called basic oxygen steelmaking, the carbon is oxidized by blowing oxygen through the liquid pig iron to form crude steel.

[0347] Desulfurization is conventionally performed during transportation of liquid iron to the steel mill by adding calcium oxide, which reacts with iron sulfide contained in the pig iron to form calcium sulfide. In some embodiments, desulfurization can also occur in the furnace or downstream of the furnace by reacting metal sulfides with CO (in the reducing gas) to form metal and carbonyl sulfide, CSO. In these or other embodiments, desulfurization can also occur in the furnace or downstream of the furnace by reacting metal sulfides with H (in the reducing gas) to form metal and carbonyl sulfide, HS.

[0348] Other types of furnaces may 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 may be renewable carbon. The present disclosure provides renewable carbon in bioreagents produced via pyrolysis of biomass. In certain embodiments, some of the carbon utilized in the furnace is not renewable carbon. In various embodiments, the percentage of renewable carbon consumed in a metal ore furnace may range from about 20% to about 100%, or any number therebetween, such as at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100%.

[0349] Some variations of the present disclosure utilize a Tecnored furnace, or a variation thereof. 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-fluxed, and self-reducing pellets. Reduction is carried out in a low-profile shaft furnace at typical reduction temperatures. The process produces hot metal (e.g., liquid iron) with high efficiency.

[0350] Tecnored technology was developed to be a cokeless steelmaking process, thus avoiding the investment and operation of environmentally harmful coke ovens in addition to significantly reducing greenhouse gas emissions in the production of hot metal. The Tecnored process uses a combination of hot and cold blasting and does not require additional oxygen. It eliminates the need for coke plants, sintering plants, and tonnage oxygen plants. Therefore, the process has much lower operating and investment costs than those of traditional steelmaking routes.

[0351] In this disclosure, the Tecnored process can be adapted for use with bio-reagents in a variety of ways. Some embodiments provide cold-bonded, self-reducing agglomerates (e.g., pellets or briquettes) produced from iron ore fines or iron-bearing residue plus a bio-reagent. These materials, mixed with fluxes and binders, are agglomerated and thermally hardened to produce briquettes / pellets with sufficient strength for the physical and metallurgical requirements of the Tecnored process. The resulting agglomerates are then smelted in a Tecnored furnace. The fuel for the Tecnored furnace can itself be a high-carbon bio-reagent.

[0352] By combining iron oxide particles and a reducing agent within the briquette, the surface area of ​​the oxide in contact with the reducing agent, and therefore the reaction rate, is dramatically increased. The self-reducing briquette can be designed to contain enough reducing agent to fully reduce the contained iron-bearing raw material, and optionally, a desired flux can be used to provide slag chemistry. The self-reducing briquette is hardened at low temperature before being fed into the furnace. The heat required to drive the reaction within the self-reducing briquette is provided by a bed of solid fuel, which can also be in the form of briquettes, onto which the self-reducing briquette is fed into the furnace.

[0353] 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, solid fuel (e.g., bioreagent) is charged. In this zone, the Boudouin reaction (C + CO2 → 2CO) is prevented, saving energy. Post-combustion in this zone of the furnace burns CO, which provides energy for preheating and reduction of the charge. Inside the pellets, the following reactions occur at very rapid rates: Fe x O y +yCO → xFe +yCO2 yCO2+yC=2yCO wherein x is at least about 1 and at most about 5, and y is at least about 1 and at most about 7.

[0354] In the melting zone, reoxidation is prevented by the reducing atmosphere in 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 bioreagents. In this zone, further reduction of residual iron oxide and slagging reactions of 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 furnace hearth and accumulate there.

[0355] This modified Tecnored process uses two different inputs of carbon units: a reducing agent and a solid fuel. The reducing agent is traditionally coal fines, but in this disclosure, the reducing agent can include a bio-reagent in the form of carbon fines. The bio-reagent is added to the mixture from which self-reducing aggregates (pellets or briquettes) are produced. The amount of carbon fines required is established by the C / F (carbon to ore fines) ratio, which can be selected to achieve complete reduction of the metal oxides.

[0356] The solid fuel (bio-reagent) does not need to be in the form of a fine powder. For example, the solid fuel can be in the form of chunks, approximately 40-80 mm in size, to meet the physical and thermal needs of the solid fuel in the Tecnored process. The solid fuel is loaded through a side feeder (to avoid the endothermic Boudoir reaction in the upper shaft) and provides the majority of the energy required by the process. This energy is generated by the primary blast (C + O2 → CO2) and the secondary blast, where the upstream CO produced by gasification of the solid fuel in the hearth is burned (2CO + O2 → 2CO2).

[0357] In a specific exemplary embodiment, the modified Tecnored process involves pelletizing iron ore fines having a size of at most about 140 mesh, bioreagent fines having a size of at most about 200 mesh, and flux, such as hydrated lime, having a size of at most about 140 mesh using cement as a binder. The pellets are hardened 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 approximately 30 to 40 minutes. Bioreagent in the form of solid fuel ranging in size from 40 mm to 80 mm is fed into the furnace below the hot pellet zone using a side feeder. Hot blast air at approximately 1150°C is blown through tuyeres located on the side of the furnace to provide combustion air for the biocarbon. A small amount of furnace gas is bled through the side feeder for use in drying and preheating the solid fuel. Cooler blast air is blown at a higher point to promote post-combustion of CO in the upper shaft. The resulting hot metal is tapped into a ladle on a ladle cart, which can tilt the ladle for slag removal. The liquid iron is optionally desulfurized in the ladle, and the slag is scraped into a slag pot. The hot metal can contain about 3-5% carbon by weight.

[0358] 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) is not required for the above reaction (Fe x O y +yCO → xFe +yCO2) or in the reaction with hydrogen as a reactant (Fe x O y The overall chemical reaction can be aided by increasing the rate or conversion of iron oxide in the reaction (xFe + yH → xFe + yH O). The reduction chemical reaction can be aided 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, whereby self-reducing pellets or briquettes are utilized in addition to the use of reducing gas in the furnace.

[0359] As previously mentioned, there are many possible furnace configurations for metal ore processing, and while this specification does not detail the various conditions and chemical reactions that may occur in every possible furnace, it will be understood by those skilled in the art that the principles of the present disclosure may be applied to essentially any furnace or process that uses carbon somewhere in the process of making metals from metal ores.

[0360] 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 (bio-reagent) and a reducing gas. In some embodiments, only the solid bio-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 bio-reagent and the reducing gas are used in the metal ore conversion process. In those embodiments using both renewable carbon sources, the percentage of total carbon usage in the metal ore conversion from the reducing gas can be about, at least about, or at most about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100%. Other carbon usage can be from pyrolysis off-gas. Alternatively, some or all of the other carbon usage can be from traditional carbon inputs such as coal fines.

[0361] Pyrolysis Processes and Systems Suitable processes and systems for pyrolyzing biomass feedstocks and thereby producing carbon-containing bio-reagents are now described in further detail. Such processes and systems may be co-located at metal ore mining or metal ore processing sites, although the present disclosure is not limited to such co-locations.

[0362] "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 at most about 10%, 5%, 1%, 0.5%, 0.1%, or 0.01% of the oxygen (on an O2 molar basis) required for complete combustion. In some embodiments, pyrolysis is carried out in the absence of oxygen.

[0363] Exemplary changes that can occur during pyrolysis include any of the following: (i) heat transfer from a heat source increases the temperature within the feedstock; (ii) the initiation of primary pyrolysis reactions at this higher temperature liberates volatiles and forms char; (iii) the flow of hot volatiles toward the cooler solids results in heat transfer between the hot volatiles and the cooler, unpyrolyzed feedstock; (iv) condensation of some of the volatiles in the cooler portions of the feedstock, followed by secondary reactions, can produce tar; (v) autocatalytic secondary pyrolysis reactions proceed while competing primary pyrolysis reactions occur simultaneously; and (vi) further pyrolysis, reforming, water-gas shift reaction, free-radical recombination, or dehydration can also occur, which are functions of residence time, temperature, and pressure profiles.

[0364] 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 water from the starting material.

[0365] In some embodiments, multiple reactor zones are designed and operated to optimize carbon yield and product quality from pyrolysis while maintaining flexibility and adjustability to feedstock variations and product requirements.

[0366] In some non-limiting embodiments, temperatures and residence times can be selected to achieve relatively slow pyrolysis chemical reactions. An advantage can be substantial preservation of the cell walls contained in the biomass structure, meaning that the final product can retain some, most, or all of the shape and strength of the starting biomass. To maximize this potential benefit, equipment that does not mechanically disrupt cell walls or convert biomass particles into small fines can be utilized. Specific reactor configurations are discussed in accordance with the process description below.

[0367] Additionally, if the feedstock is a ground or sized feedstock, such as wood chips or pellets, it may be desirable to carefully ground or size the feedstock. Careful initial processing preserves the strength and cell wall integrity present in the natural feedstock source (e.g., wood). This may also be important if the final product is to retain some, most, or all of the shape and strength of the starting biomass.

[0368] 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 ruptures cell walls and initiates rapid decomposition of the solid phase into steam and gas. This first zone can be considered mild pyrolysis.

[0369] 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 solid material that is a high-carbon reaction intermediate. Biomass components (primarily cellulose, hemicellulose, and lignin) decompose to create vapors that escape by penetrating pores or by creating new nanopores. The latter effect contributes to the creation of porosity and surface area.

[0370] In some embodiments, a third zone of the pyrolysis reactor is configured to receive the high-carbon reaction intermediates and provide some cooling of the solids. The third zone may be at a lower temperature than the second zone. In the third zone, chemical reactions and mass transfer may be surprisingly complex. Without being limited by a particular theory or proposed mechanism, it is believed that secondary reactions may occur in the third zone. Carbon-containing components in the gas phase may decompose to form additional fixed carbon or become adsorbed onto carbon. Thus, the final carbonaceous material may optionally be more than simply a solid, devolatilized residue of a processing step, but rather may include additional carbon deposited from the gas phase, such as by decomposition of organic vapors (e.g., tars) that can form carbon.

[0371] Certain embodiments extend the concept of additional carbon formation by including a separate unit in which the cooled carbon is subjected to an environment containing carbon-containing species to enhance 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.

[0372] There are numerous options with regard to intermediate input and output (purge or probe) streams of one or more phases present in any particular zone, various mass and energy recycle schemes, various additives that can be introduced anywhere in the process, adjustability of process conditions, including both reaction and separation conditions to tailor product distribution, etc. Zone-specific input and output streams allow for better process monitoring and control, such as by FTIR sampling and dynamic process adjustment.

[0373] Some embodiments do not use fast pyrolysis, and some embodiments do not use slow pyrolysis. Surprisingly, high quality carbon materials, including compositions with very high percentages of fixed carbon, can be obtained from the disclosed processes and systems.

[0374] In some embodiments, the pyrolysis process for producing high carbon bio-reagents comprises: (a) providing a carbon-containing feedstock comprising biomass; (b) optionally drying the feedstock to remove moisture contained within the feedstock; (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 at a temperature selected from about 250°C to about 700°C for at least 10 minutes, thereby producing high temperature pyrolysis solids, condensable vapors, and non-condensable gases; (e) separating condensable vapors and non-condensable gases from the high temperature pyrolysis solids; (f) cooling the high temperature pyrolysis solid, thereby producing a cooled pyrolysis solid; (g) recovering the cooled pyrolysis solid-containing high-carbon biological reagent.

[0375] For purposes of this disclosure, "biomass" shall be construed as any living material or a mixture of living and non-living materials. Essentially, biomass 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.

[0376] Biomass can include, 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 disclosed embodiments utilizing biomass, the biomass feedstock can include one or more materials selected from timber harvest residues, softwood chips, hardwood chips, tree branches, tree stumps, wood knots, leaves, bark, sawdust, off-spec paper pulp, cellulose, corn, corn stover, wheat straw, rice straw, sugarcane bagasse, switchgrass, miscanthus, animal manure, municipal waste, municipal sewage, commercial waste, grape pomace, almond shells, pecan shells, coconut shells, coffee grounds, grass pellets, hay pellets, wood pellets, cardboard, paper, carbohydrates, plastics, and textiles. Those skilled in the art will readily appreciate that the raw material options are virtually limitless.

[0377] The present disclosure can also be used with carbon-containing feedstocks other than biomass, such as fossil fuels (e.g., coal or petroleum coke), or any mixture of biomass and fossil fuels (e.g., biomass / coal blends). In some embodiments, the carbon-containing feedstock is or includes coal, oil shale, crude oil, asphalt, or solids from crude oil processing (such as petroleum coke). Feedstocks can include scrap tires, recycled plastics, recycled paper, construction waste, demolition waste, and other waste or recycled materials. For clarity, any method, apparatus, or system described herein can be used with any carbonaceous feedstock. The carbon-containing feedstock can be transportable by any known means, such as truck, train, ship, barge, tractor-trailer, or any other vehicle or transportation means.

[0378] The selection of a particular raw material or materials is generally made in a manner that favors process economics. Regardless of the raw material selected, there may be screening to remove undesirable materials. The raw material may optionally be dried before processing.

[0379] The raw materials used can be provided or processed into a wide variety of 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 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 pellets or other agglomerated forms of particles pressed together or otherwise bound by a binder or the like.

[0380] It should be noted that size reduction is a costly and energy-intensive process. Pyrolyzed materials can be sized with significantly less energy input, i.e., 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 there is not necessarily any significant particle size reduction during processing. The ability to process very large feedstock pieces is an important economic advantage of the present disclosure. Of note, some market applications of high-carbon products actually require large sizes (e.g., on the order of centimeters), and therefore in some embodiments, large pieces are sourced, produced, and sold.

[0381] If it is desired to produce a final carbonaceous bio-reagent with structural integrity, such as a cylindrical shape, there are at least two options in the context of this disclosure. First, the material produced from the process can be collected and then further mechanically processed into the desired form. For example, the product can be pressed or pelletized with a binder. A second option is to utilize a feed material that generally has the desired size or shape for the final product and use processing steps that do not destroy the basic structure of the feed material. In some embodiments, the feed and product have similar geometric shapes, such as spheres, cylinders, or cubes.

[0382] 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.

[0383] The starting feedstock may be provided at a range of moisture levels, as will be appreciated. In some embodiments, the feedstock may already be sufficiently dry and therefore does not require further drying prior to pyrolysis. It may be desirable to utilize commercial sources of biomass that typically contain moisture and feed the biomass through a drying step before introducing it into the pyrolysis reactor. However, in some embodiments, dry feedstock may be utilized.

[0384] In the pyrolysis reactor, it is desirable to provide a relatively low-oxygen environment, 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, uncontrolled combustion should be avoided in the pyrolysis reactor for safety reasons. Some amount of total carbon oxidation to CO may occur, and the heat released from the exothermic oxidation may support the endothermic pyrolysis chemical reaction. Large amounts of carbon oxidation, including partial oxidation to synthesis gas, reduce the carbon yield to solids.

[0385] In practice, it can be difficult to achieve a strictly 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 may be preferable to remove air from the feed before it is introduced into the reactor. There are various ways to remove or reduce air in the feed.

[0386] In some embodiments, a degassing unit is utilized before or after drying, in which the feedstock is conveyed in the presence of another gas that can remove adsorbed oxygen and penetrate the feedstock pores to remove oxygen from the pores. Essentially, any gas with less than 21% O by volume can be used, with varying effectiveness. In some embodiments, nitrogen is used. In some embodiments, CO or CO is used. Mixtures can be used, such as a mixture of nitrogen and small amounts of oxygen. Water vapor may be present in the degassing gas, but adding significant moisture back to the feed should be avoided. The effluent from the degassing unit can be purged (to the atmosphere or an effluent treatment unit) or recycled.

[0387] 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 would be highly diluted. In this embodiment, it may be advantageous to introduce the degassed effluent gas into the last zone of the reactor if the reactor is operated in a countercurrent configuration.

[0388] Various types of degassing units can be used. If drying is performed, drying and subsequent degassing can be performed due to the inefficiency of scrubbing soluble oxygen from the moisture present. In certain embodiments, the drying and degassing steps are combined into a single unit, or some amount of degassing is achieved during drying, etc.

[0389] The optionally dried and optionally degassed feedstock is introduced into a pyrolysis reactor or multiple reactors 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 feed system incorporates an air knife.

[0390] When a single pyrolysis reactor is used, there can be multiple zones, such as two, three, four, or more zones, which can allow for separate control of temperature, solids residence time, gas residence time, gas composition, flow pattern, or pressure to adjust overall process performance.

[0391] References to "zones" shall be interpreted broadly to include regions of space within a single physical unit, physically separated units, or any combination thereof. With respect to continuous reactors, zone boundaries may relate to structures such as the presence of flights within the reactor or separate heating elements for providing heat to separate zones. Alternatively or additionally, zone boundaries in continuous reactors may relate to functions such as, for example, separate temperatures, fluid flow patterns, solids flow patterns, extent of reaction, etc. In single batch reactors, a "zone" is an operating regime in time rather than space. Multiple batch reactors may also be used.

[0392] It will be understood that there is not necessarily an abrupt transition from one zone to another. For example, the boundary between the preheat zone and the pyrolysis zone may be somewhat arbitrary. Some amount of pyrolysis may occur in a portion of the preheat zone, and some amount of "preheating" may continue to occur in the pyrolysis zone. The temperature profile in the reactor may be continuous, including at zone boundaries within the reactor.

[0393] Some embodiments employ a first zone operated 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 bombard the biomass material, rupture cell walls, and initiate rapid decomposition of the solid phase into vapors and gases.

[0394] All references to zone temperatures herein should be interpreted non-limitingly to include temperatures that may be applied to the bulk solids present, or the gas phase, or the reactor wall (process side). It will be understood that temperature gradients exist in each zone, both axially and radially, and over time (i.e., after start-up or due to transients). Thus, references to zone temperatures may be to average temperatures or other effective temperatures that may affect actual kinetics. Temperatures may be measured directly by thermocouples or other temperature probes, or may be measured or estimated indirectly by other means.

[0395] The second zone, or generally the first pyrolysis zone, is operated under pyrolysis or carbonization conditions. The temperature of the second zone can range from about 250°C to about 700°C, or any number therebetween, for example, about, or at least about, or at most 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 and leaving a significant amount of solid material as a high-carbon reaction intermediate. Biomass components (primarily cellulose, hemicellulose, and lignin) decompose to create steam, which escapes by percolation through pores or by creating 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 properties.

[0396] The third zone, or cooling zone, is operated to cool the high-carbon 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.

[0397] Chemical reactions can continue to occur in the cooling zone. Without being limited to a particular theory, it is believed that a secondary pyrolysis reaction can be initiated in the third zone. Carbon-containing components that are in the gas phase can condense (due to the decrease in temperature in the third zone). 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 the adsorbed species and the fixed carbon. One exemplary reaction that can occur is the Boudouin reaction to convert carbon monoxide to carbon dioxide and fixed carbon.

[0398] The residence time of the reactor zones can vary. There is an interaction of time and temperature, such that for a desired amount of pyrolysis, higher temperatures can allow for shorter reaction times, and vice versa. The residence time in a continuous reactor (zone) is the volume divided by the volumetric flow rate. The residence time in a batch reactor is the batch reaction time after heating to the reaction temperature.

[0399] It should be recognized that in a multiphase reactor, multiple residence times exist. In the present context, there are residence times (and residence time distributions) for both the solid and vapor phases in each zone. For a given apparatus using multiple zones, at a given throughput, the residence times across the zones are generally coupled on the solid side, but if multiple inlet and outlet ports are utilized in the individual zones, the residence times may not be coupled on the vapor side. The solid and vapor residence times are not coupled.

[0400] 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, a sufficient time is desirable to allow the biomass to reach the desired preheat temperature. The heat transfer rate, which depends on the particle type and size, physical equipment, and heating parameters, dictates the minimum residence time required to allow the solids to reach the desired preheat temperature. Additional time may be undesirable unless some amount of mild pyrolysis is intended in the preheat zone, as it contributes to higher capital costs.

[0401] The solids residence time in the pyrolysis zone can be selected from about 10 minutes to about 120 minutes, for example, 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 for the necessary heat transfer followed by the carbonization chemical reaction. For times less than about 10 minutes, the temperature needs to be very high, such as above 700°C, to remove a large amount of non-carbon elements. This temperature promotes fast pyrolysis and the production of vapors and gases derived from the carbon itself, which should be avoided if the intended product is solid carbon.

[0402] In a static system, there will be an equilibrium conversion that can be substantially reached at a certain time. When, as in certain embodiments, steam is continuously flowing over the solids with continuous devolatilization, the equilibrium constraint can be removed to allow pyrolysis and devolatilization to continue until the reaction rate approaches zero. Longer times tend not to substantially alter the remaining refractory solids.

[0403] 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 dictate the minimum residence time required to allow the carbon to cool. Unless some amount of secondary pyrolysis is desired, additional time may not be desirable.

[0404] As described above, the vapor phase residence times can be independently selected and controlled. The vapor residence time in the preheating zone can be selected from about 0.1 minutes to about 15 minutes, e.g., 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, e.g., 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, e.g., about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. A short vapor residence time promotes rapid clearing of volatiles from the system, while a longer vapor residence time promotes reaction of components in the vapor phase with the solid phase.

[0405] 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, but with simulated countercurrent flow of vapor, for example, by periodically introducing and removing the vapor phase from the batch vessel.

[0406] A variety of flow patterns may be desired or observed. In chemical reactions and simultaneous separations involving multiple phases in multiple reactor zones, the fluid dynamics can become very complex. Solids flow can approach plug flow (well mixed in the radial dimension), while vapor flow can approach perfectly mixed flow (high velocity transport in both the radial and axial dimensions). Multiple inlet and outlet ports for vapor can contribute to overall mixing.

[0407] The pressure in each zone can be separately selected and controlled. The pressure in 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 control of pressure is possible when multiple gas inlets and outlets are used, including vacuum ports for withdrawing gas when subatmospheric zone pressures are desired.

[0408] The process can, in some embodiments, be conveniently operated at atmospheric pressure. Operation at atmospheric pressure has many advantages, ranging from mechanical simplicity to improved safety. In particular embodiments, the pyrolysis zone is operated at a pressure of about 90 kPa, 95 kPa, 100 kPa, 101 kPa, 102 kPa, 105 kPa, or 110 kPa (absolute).

[0409] Vacuum operation (e.g., 10-100 kPa) promotes rapid sweep of volatiles from the system. Higher pressures (e.g., 100-1000 kPa) can be useful when off-gas is fed to high-pressure operation. Higher pressures can also be useful to promote heat transfer, chemical reactions, or separations.

[0410] The step of separating the condensable vapors and non-condensable gases from the high-temperature pyrolysis solids can be accomplished in the reactor itself or using a separate separation unit. A substantially inert sweep gas can be introduced into one or more zones. The condensable vapors and non-condensable gases are then carried away from the zones in the sweep gas and exit the reactor.

[0411] The sweep gas may be, for example, N2, Ar, CO, CO2, H2, H2O, CH4, other light hydrocarbons, or combinations thereof. The sweep gas may be initially preheated before introduction, or may be cooled if obtained from a heated source.

[0412] The sweep gas more completely removes volatile components by removing them from the system before they can condense or further react. The sweep gas allows volatiles to be removed at a higher rate than would be possible from volatilization alone at a given process temperature. Alternatively, the use of a sweep gas allows more moderate temperatures to be used to remove a particular amount of volatile material. The reason the sweep gas improves volatile removal is because the mechanism of separation is not simply relative volatility, but rather liquid / vapor phase separation assisted by the sweep gas. The sweep gas can reduce the mass transfer limitation of volatilization as well as the thermodynamic limitation by continuously depleting a given volatile species, allowing more volatile species to evaporate and achieve thermodynamic equilibrium.

[0413] Some embodiments remove gases full of volatile organic carbon from subsequent processing stages to produce products with high fixed carbon. Otherwise, the volatile carbon may be adsorbed or absorbed onto the pyrolyzed solids, thereby requiring additional energy (cost) to achieve a purer form of carbon that may be desired. It is also speculated that rapid removal of vapors can increase porosity in the pyrolysis solids. Higher porosity is desirable for some products.

[0414] In certain embodiments, the sweep gas, in conjunction with a relatively low process pressure, such as atmospheric pressure, provides fast vapor removal without requiring large amounts of inert gas.

[0415] 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.

[0416] 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 or pyrolysis zone. In some embodiments, a sweep gas is introduced into the pyrolysis zone and extracted from the pyrolysis or 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 can be introduced into each of the preheating zone, pyrolysis zone, and cooling zone, and can also be extracted from each of the zones.

[0417] In some embodiments, the zone or zones in which separation is performed are units physically separate 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.

[0418] The sweep gas can be introduced continuously, especially when the solids flow is continuous. If the pyrolysis reaction is operated as a batch process, the sweep gas can be introduced after a certain amount of 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 suitable valves and controls.

[0419] The volatile-containing sweep gas can exit 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 for controlled air 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.

[0420] The effluent of the thermal oxidizer is a hot gas stream containing water, carbon dioxide, and nitrogen. This effluent stream can be purged directly to the air exhaust, if desired. The energy content of the thermal oxidizer effluent can be recovered, for example, in a waste heat recovery unit. The energy content can also be recovered by heat exchange with another stream (such as a sweep gas). The energy content can be utilized by directly or indirectly heating or assisting in heating units elsewhere in the process, such as a dryer or reactor. In some embodiments, essentially all of the thermal oxidizer effluent is used to indirectly heat (the utility side) the dryer. The thermal oxidizer can use fuels other than natural gas.

[0421] The yield of carbonaceous materials can vary depending on the factors mentioned above, 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 between condensable vapors, such as terpenes, tars, alcohols, acids, aldehydes, or ketones, and non-condensable gases, such as carbon monoxide, hydrogen, carbon dioxide, and methane. The relative amount of condensable vapors compared to non-condensable gases also depends on process conditions, including the presence of water.

[0422] With respect to 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 from about 40% to about 70% of the carbon contained in the starting feedstock. The remaining carbon forms, to varying degrees, methane, carbon monoxide, carbon dioxide, light hydrocarbons, aromatics, tars, terpenes, alcohols, acids, aldehydes, or ketones.

[0423] In some embodiments, these compounds, or portions thereof, are combined with carbon-enriched solids to concentrate the carbon and energy content of the product. In these embodiments, some or all of the gas stream resulting from the reactor, containing various vapors, can be at least partially condensed and then passed over cooled pyrolysis solids from a cooling zone or a separate cooling unit. These embodiments are described in more detail below.

[0424] Following reaction and cooling in the cooling zone (if present), the carbonaceous solids may be introduced into a separate cooling unit. In some embodiments, the solids are recovered 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., such as ambient temperature. In some embodiments, a water quench 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.

[0425] 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 the drying is performed at least in part using the superheated steam from the cooling unit. Optionally, the cooling unit can be operated to first cool the warm pyrolysis solids with steam to reach a first cooling unit temperature, and then cool them with air to reach 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.

[0426] Following cooling to ambient conditions, the carbonaceous solids may be collected, stored, transported to another on-site operation, shipped to another site, or otherwise disposed of, traded, or sold. The solids may be fed to a unit to reduce particle size. A variety of size reduction units are known in the art, including crushers, shredders, grinders, pulverizers, jet mills, pin mills, and ball mills.

[0427] Screening or some other means for particle size-based separation may be included. Grinding, if present, may be 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 uses. In some embodiments, the cooled pyrolysis solids are ground into a fine powder, such as a finely divided carbon or activated carbon product.

[0428] Various additives can be introduced throughout the process before, during, or after any step disclosed herein. Additives can be broadly categorized as 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 bioreagent or downstream products incorporating the reagent. Certain additives can provide enhanced process and product (bioreagent or bioreagent-containing products) properties.

[0429] The additives can be added before, during, or after any one or more steps of the process, including adding them to the feedstock itself at any time before or after it is harvested. The additive treatment can be incorporated before, during, or after sizing, drying, or other preparation of the feedstock. The additives can be incorporated into or on the feedstock supply facility, transport truck, unloading equipment, storage bin, conveyor (including open or closed conveyor), dryer, process heater, or any other unit. The additives can be added anywhere in the pyrolysis process itself using a suitable means for introducing the additive. If desired, the additives can be added after carbonization or even after comminution.

[0430] In some embodiments, the additive is selected from a metal, a metal oxide, a metal hydroxide, or a combination thereof. For example, the additive may be selected from, but is in no way limited to, magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorospar, bentonite, calcium oxide, lime, and combinations thereof.

[0431] In some embodiments, the additive is selected from an acid, a base, or a salt thereof. For example, the additive may be selected from, but is in no way limited to, sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, or a combination thereof.

[0432] 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 combination 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.

[0433] The additives can result in a final product with a higher energy content (energy density). The increase in energy content can result from an increase in total carbon, fixed carbon, volatile carbon, or even hydrogen. Alternatively or additionally, the increase in energy content can result from the removal of non-combustible materials or materials with a lower energy density than carbon. In some embodiments, the additives reduce the extent of liquid formation in favor of solid and gas formation, or in favor of solid formation.

[0434] Without being limited to any particular hypothesis, the additives can chemically modify the starting biomass or treated biomass prior to pyrolysis to reduce cell wall breakdown for greater strength / integrity. In some embodiments, the additives can increase the fixed carbon content of the biomass feedstock prior to pyrolysis.

[0435] Additives can result in bioreagents with improved mechanical properties, such as yield strength, compressive strength, tensile strength, fatigue strength, impact strength, elastic modulus, bulk modulus, or shear modulus. Additives can improve mechanical properties simply by their presence (e.g., the additive itself imparts strength to the mixture) or by some transformation that occurs within the additive phase or the resulting mixture. For example, a reaction such as vitrification can occur within a portion of the bioreagent that contains the additive, thereby improving the final strength.

[0436] 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 from a liquid solution (such as in an aqueous solution or solvent) or by immersion in a tank, bin, bag, or other container.

[0437] In certain embodiments, an immersion pretreatment is used, in which the solid feedstock is immersed, either batchwise or continuously, in a bath containing the additive for a time sufficient to impregnate the additive into the solid feed material.

[0438] In some embodiments, the additives applied to the feedstock can reduce the energy requirements for pyrolysis or increase the yield of the carbonaceous product. In these or other embodiments, the additives applied to the feedstock can provide functionality that is desirable for the intended use of the carbonaceous product.

[0439] 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, process capacities (of feedstock, product, or both) are at least about 1 kg / day, 10 kg / day, 100 kg / day, 1 ton / day (all tons are metric tons), 10 ton / day, 100 ton / day, 500 ton / day, 1000 ton / day, 2000 ton / day, or more.

[0440] In some embodiments, the solids produced, or a portion of the solids, 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 be higher in fixed carbon. 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.

[0441] In some embodiments, the pyrolyzed material is recovered and then fed to a separate unit for further pyrolysis to create a product with higher carbon purity. In some embodiments, the secondary process can be carried out in a simple container, such as a steel drum, through which a heated inert gas (such as 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, another stream of inert gas, initially at, for example, ambient temperature, can be passed through the solids to cool them and then returned to the inert gas preheat system.

[0442] Some variations of the present disclosure include: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operable communication with the supplying apparatus and configured to remove moisture contained within the carbon-containing feedstock; (c) a multi-zone reactor disposed in operative communication with the dryer, the multi-zone reactor comprising 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 solids cooler disposed in operable communication with the multi-zone reactor; (e) utilizing a high-carbon biological reagent production system comprising a high-carbon biological reagent recovery unit disposed in operable communication with the solid-state cooler;

[0443] Some variations are: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operable communication with the supplying apparatus and configured to remove moisture contained within the carbon-containing feedstock; (c) an optional preheater disposed in operable communication with the dryer and configured to heat or gently pyrolyze the feedstock; (d) a pyrolysis reactor disposed in operable communication with the preheater and configured to pyrolyze the feedstock; (e) a cooler disposed in operable communication with the pyrolysis reactor and configured to cool the pyrolysis solids; (f) a high-carbon biological reagent recovery unit disposed in operative communication with the cooler, The system utilizes a high carbon bio-reagent generation system configured with a gas outlet for removing condensable vapors and non-condensable gases from the solids.

[0444] The feed system can be physically integrated with the multi-zone reactor, such as through the use of a screw feed system or auger mechanism to introduce the feed solids into the first reaction zone.

[0445] In some embodiments, the system further comprises a preheating zone disposed in operative communication with the pyrolysis zone. Each of the pyrolysis zone, cooling zone, and preheating zone (if present) can be located within a single unit or can be located in separate units.

[0446] Optionally, the dryer can be configured as a drying zone within a multi-zone reactor. Optionally, a 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).

[0447] 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.

[0448] The multi-zone reactor can be configured with at least a first gas inlet and a first gas outlet, which can be disposed in communication with different zones or the same zone.

[0449] 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 in the multi-zone reactor is configured with a gas inlet and a gas outlet.

[0450] The gas inlets and outlets not only allow for the introduction and removal of vapors, but the gas outlets (probes) in particular allow for accurate process monitoring and control over various stages of the process, up to and potentially including all stages of the process. Accurate process monitoring is expected to result in improved yield and efficiency, both dynamically and over time, when operating history can be utilized to adjust process conditions.

[0451] 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 any number of ways, such as by adjusting the feed rate, the rate of inert gas sweep, the temperature (in one or more zones), the pressure (in one or more zones), additives, etc.

[0452] As intended herein, "monitoring and controlling" via a reactive gas probe should be interpreted to include any one or more sampling via the reactive gas probe, and optionally, if deemed necessary or desirable, making process or equipment adjustments based on the measurements using well-known principles of process control (e.g., feedback, feedforward, proportional-integral-derivative logic, etc.).

[0453] The reaction gas probe can be configured to extract a gas sample in many ways. For example, the sampling line can have a pressure lower than the pyrolysis reactor pressure, so that when the sampling line is opened, a quantity of gas can be easily extracted from the pyrolysis zone. The sampling line can be under vacuum, such as when the pyrolysis zone is at near atmospheric pressure. The reaction gas probe can be associated with one gas output or a portion thereof (e.g., a line branching off from the gas output line).

[0454] In some embodiments, both the gas input and gas output are utilized as reactive gas probes by periodically introducing an inert gas into the zone and withdrawing the inert gas from the gas output along with a process sample (a "sample sweep"). Such a configuration can be used in zones that do not have a gas inlet / outlet for a substantially inert gas for processing, or the reactive gas probe can be associated with a separate gas inlet / outlet in addition to the process inlet and outlet. The sampling inert gas that is periodically introduced and withdrawn for sampling (in embodiments utilizing a sample sweep) can be different from the process inert gas, as desired, either for analytical accuracy reasons or to introduce an analytical tracer.

[0455] For example, the acetic acid concentration in the gas phase of the pyrolysis zone can be measured using a gas probe to extract a sample, which is then analyzed using a suitable technique (such as gas chromatography, GC, mass spectrometry, MS, GC-MS, or Fourier transform infrared spectroscopy, FTIR). The CO or CO2 concentration in the gas phase can be measured and used, for example, as an indicator of pyrolysis selectivity to gases / vapors. The terpene concentration in the gas phase can be measured and used, for example, as an indicator of pyrolysis selectivity to liquids.

[0456] In some embodiments, the system further comprises 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).

[0457] A gas probe for the cooling zone can be 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 measured amount of a particular species. The correlation can be developed separately or can be established after a period of process operation.

[0458] A gas probe for the drying zone can be useful to determine the degree of drying, for example by measuring moisture content. A gas probe in the preheat zone can be useful, for example, to determine the degree of any mild pyrolysis that occurs.

[0459] In certain embodiments, the cooling zone is configured with a gas inlet and the pyrolysis zone is configured with a gas outlet to generate a substantially countercurrent flow of the gas phase relative to the solid phase. Alternatively or additionally, the preheating zone (if present) can be configured with a gas outlet to generate a substantially countercurrent flow of the gas phase relative to the solid phase. Alternatively or additionally, the drying zone can be configured with a gas outlet to generate a substantially countercurrent flow.

[0460] The one or more pyrolysis 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 rotating 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.

[0461] 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 at one end of a screw. The screw mixes the sand and feedstock and carries them through the reactor. The screw can provide good control of feedstock residence time and does not dilute the pyrolysis products with carrier or fluidizing gas. The sand can be reheated in a separate vessel.

[0462] In some embodiments where an ablation process is used, the feedstock is moved at high velocity relative to the hot metal surface. Ablation of any char that forms on the surface can maintain a high heat transfer rate. Such an arrangement 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.

[0463] In some embodiments where a fluidized bed reactor is used, the feedstock may be introduced into a bed of hot sand fluidized by a gas, which may typically be recycled product gas. References herein to "sand" also include similar substantially inert materials such as glass particles, recovered ash particles, and the like. The high heat transfer rate from the fluidized sand can result in rapid heating of the feedstock. There may be some abrasion due to friction with the sand particles. Heat is typically provided by heat exchanger tubes through which hot combustion gases flow.

[0464] A circulating fluidized bed reactor can be used, in which gas, sand, and feedstock move together. Exemplary transport gases include recycled product gas and combustion gas. The high heat transfer rate from the sand ensures rapid heating of the feedstock, and ablation is expected to be stronger 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.

[0465] In some embodiments, the multi-zone reactor is a continuous reactor comprising a feedstock inlet, a plurality of spatially separated reaction zones configured to separately control the temperature and mixing within each of the reaction zones, 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.

[0466] 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 separately adjustable heating means independently selected from electrical heat transfer, steam heat transfer, hot oil heat transfer, phase change heat transfer, waste heat heat transfer, or combinations thereof. In some embodiments, the reactor zones are heated with an effluent stream from a thermal oxidizer, if present. In some embodiments, at least one additional reactor zone is heated with an effluent stream from a thermal oxidizer, if present.

[0467] The reactor can be configured to separately adjust the gas phase composition and gas phase residence time of at least two reaction zones up to all reaction zones present in the reactor.

[0468] The reactor can be equipped with a second gas inlet or a second gas outlet. In some embodiments, the reactor is configured with a gas inlet for each reaction zone. In these or other embodiments, the reactor is configured with a gas outlet for each reaction zone. The reactor can be a co-current or counter-current reactor.

[0469] In some embodiments, the feedstock inlet comprises a screw or auger feed mechanism, hi some embodiments, the carbonaceous solids outlet comprises a screw or auger output mechanism.

[0470] Certain embodiments utilize a rotary calciner equipped with a screw feeder. In these embodiments, the reactor is axially rotatable, i.e., the reactor rotates about its central axis. The rotational speed affects solids flow patterns and heat and mass transfer. Each of the reaction zones can be configured with flights disposed on the interior walls to provide agitation of the solids. The flights can be independently adjustable in each of the reaction zones.

[0471] Other means of agitating the solids can be used, such as an auger, screw, or paddle conveyor. In some embodiments, the reactor contains a single continuous auger positioned throughout each of the reaction zones. In other embodiments, the reactor contains twin screws positioned throughout each of the reaction zones.

[0472] Some systems are specifically designed with the ability to maintain the approximate size of the feedstock throughout the process, i.e., the ability to process biomass feedstock without destroying or significantly damaging its structure. In some embodiments, the pyrolysis zone does not contain augers, screws, or rakes, which tend to significantly reduce the size of the feedstock being pyrolyzed.

[0473] In some embodiments of the present disclosure, the system further includes a thermal oxidizer disposed in operative communication with the outlet through which the condensable vapors and non-condensable gases are removed. The thermal oxidizer can be configured to receive a separate fuel (such as natural gas) and an oxidant (such as air) in a combustion chamber adapted to combust the fuel and the condensable vapors. Certain non-condensable gases, such as CO or CH4, can also be oxidized to CO2.

[0474] When a thermal oxidizer is used, the system can include a heat exchanger disposed between the thermal oxidizer and the dryer and configured to utilize the heat of combustion for the dryer. This embodiment can significantly contribute to the overall energy efficiency of the process.

[0475] In some embodiments, the system further comprises a carbon enrichment unit disposed in operative communication with the solids cooler and configured to combine the condensable vapor in at least partially condensed form with the solids, the carbon enrichment unit being capable of increasing the carbon content of the high-carbon biological reagent obtained from the recovery unit.

[0476] The system can further include a separate pyrolysis unit adapted to further pyrolyze the high-carbon biological reagent to further increase its carbon content. The separate pyrolysis unit can be a relatively simple container, unit, or device, such as a tank, barrel, bin, drum, tote, sack, or roll-off.

[0477] The entire system may be at a fixed location or distributed over several locations. The system may be built using modules that can be easily replicated for practical scale-up. The system may also be built using economy of scale principles, as is well known in the process industries.

[0478] Some variations on carbon enrichment of solids are now further described. In some embodiments, the process for producing a high-carbon bio-reagent comprises: (a) providing a carbon-containing feedstock comprising biomass; (b) optionally drying the feedstock to remove moisture contained within the feedstock; (c) optionally degassing the feedstock to remove interstitial oxygen, if any, contained in the feedstock; (d) pyrolyzing the feedstock in a pyrolysis zone in the presence of a substantially inert gas for at least 10 minutes and at a pyrolysis temperature selected from about 250°C to about 700°C, thereby producing high temperature pyrolysis solids, condensable vapors, and non-condensable gases; (e) separating condensable vapors and non-condensable gases from the high temperature pyrolysis solids; (f) cooling the hot pyrolysis solid in a cooling zone in the presence of a substantially inert gas for at least 5 minutes and at a cooling temperature below the pyrolysis temperature, thereby producing a warm pyrolysis solid; (g) optionally cooling the warm pyrolysis solid to produce a cold pyrolysis solid; (h) then passing the condensable vapor or non-condensable gas from step (e) through the warm or cold pyrolysis solid to form an enhanced pyrolysis solid having an increased carbon content; (i) recovering the high carbon bioreagent containing the enriched pyrolysis solid.

[0479] In some embodiments, step (h) comprises passing the condensable vapor from step (e) in vapor or condensed form through the warm pyrolytic solids, thereby producing an enhanced pyrolytic solid having an increased carbon content. In some embodiments, step (h) comprises passing the non-condensable gas from step (e) through the warm pyrolytic solids, thereby producing an enhanced pyrolytic solid having an increased carbon content.

[0480] Alternatively or additionally, the vapor or gas can be contacted with the cold pyrolytic solid. In some embodiments, step (h) comprises passing the condensable vapor from step (e) in vapor or condensed form through the cold pyrolytic solid, thereby producing an enhanced pyrolytic solid having an increased carbon content. In some embodiments, step (h) comprises passing the non-condensable gas from step (e) through the cold pyrolytic solid, thereby producing an enhanced pyrolytic solid having an increased carbon content.

[0481] In certain embodiments, step (h) comprises passing substantially all of the condensable vapors from step (e), in vapor or condensed form, through cold pyrolytic solids, thereby producing enhanced pyrolytic solids having an increased carbon content. In certain embodiments, step (h) comprises passing substantially all of the non-condensable gases from step (e) through cold pyrolytic solids, thereby producing enhanced pyrolytic solids having an increased carbon content.

[0482] The process can include various methods of treating or separating the steam or gas prior to using the steam or gas for carbon enrichment. For example, the intermediate feed stream comprising condensable steam and non-condensable gas obtained from step (e) can be fed to a separation unit configured to produce at least first and second output streams. In certain embodiments, the intermediate feed stream comprises all of the condensable steam, all of the non-condensable gas, or both.

[0483] Separation techniques can include or use distillation columns, flash vessels, centrifuges, cyclones, membranes, filters, packed beds, capillary columns, etc. Separations can be based primarily on, for example, distillation, absorption, adsorption, or diffusion, and can exploit differences in vapor pressure, activity, molecular weight, density, viscosity, polarity, chemical functionality, affinity to a stationary phase, and any combination thereof.

[0484] In some embodiments, the first and second output streams are separated from the intermediate feed stream based on relative volatility. For example, the separation unit can be a distillation column, a flash tank, or a condenser.

[0485] Thus, in some embodiments, the first output stream comprises condensable vapors and the second output stream comprises non-condensable gases. The condensable vapors can comprise carbon-containing compounds selected from terpenes, alcohols, acids, aldehydes, or ketones. The vapors from pyrolysis can comprise aromatic compounds such as benzene, toluene, ethylbenzene, and xylene. Heavier aromatic compounds such as refractory tars can be present in the vapors. The non-condensable gases can comprise carbon-containing molecules selected from carbon monoxide, carbon dioxide, or methane.

[0486] In some embodiments, the first and second output streams are intermediate feed streams that have been separated based on their relative polarity. For example, the separation unit can be a stripping column, a packed bed, a chromatography column, or a membrane.

[0487] Thus, in some embodiments, the first output stream comprises polar compounds and the second output stream comprises non-polar compounds. The polar compounds can comprise carbon-containing molecules selected from methanol, furfural, or acetic acid. The non-polar compounds can comprise carbon-containing molecules selected from carbon monoxide, carbon dioxide, methane, terpenes, and terpene derivatives.

[0488] Step (h) can increase the total carbon content of the high-carbon biological reagent relative to an otherwise identical process that does not include step (h). The degree of increase in carbon content can be, for example, about 1%, 2%, 5%, 10%, 15%, 25%, or even more in various embodiments.

[0489] In some embodiments, step (h) increases the fixed carbon content of the high-carbon bioreagent. In these or other embodiments, step (h) increases the volatile carbon content of the high-carbon bioreagent. The volatile carbon content is carbon attributable to volatile materials in the reagent. Volatile materials can be, but are not limited to, aliphatic or aromatic compounds (e.g., terpenes); oxygenates, including alcohols, aldehydes, or ketones; and hydrocarbons, including various tars. Volatile carbon can remain bound or adsorbed to solids at ambient conditions, but upon heating, is released before the fixed carbon is oxidized, gasified, or released as vapor.

[0490] Depending on the conditions associated with step (h), it is possible for some amount of volatile carbon to become fixed carbon (e.g., via Boudoir carbon formation from CO). Volatile materials can enter the micropores of the fixed carbon and exist as condensed / adsorbed species, but remain relatively volatile. This residual volatility may be more advantageous for fuel applications compared to product applications requiring high surface area and porosity.

[0491] Step (h) can increase the energy content (i.e., energy density) of the high-carbon biological reagent. The increase in energy content can result from an increase in total carbon, fixed carbon, volatile carbon, or even hydrogen. The degree of increase in energy content can be, for example, about 1%, 2%, 5%, 10%, 15%, 25%, or even higher in various embodiments.

[0492] Further separation can be used to recover one or more non-condensable gases or condensable vapors for use within the process or further processing, for example, to produce purified carbon monoxide or hydrogen.

[0493] As another example, separation of acetic acid can be performed, followed by reduction of the acetic acid to ethanol, which can be achieved, at least in part, using hydrogen derived from the non-condensable gases produced.

[0494] Condensable vapors can be used for energy in the process (such as by thermal oxidation) or for carbon enrichment to increase the carbon content of the high-carbon bioreagent. Certain non-condensable gases, such as CO or CH4, can be utilized for energy in the process or as part of the substantially inert gas for the pyrolysis step. Combinations of any of the above are also possible.

[0495] A potential advantage of including step (h) is that the gas stream is scrubbed and the resulting gas stream is enriched in CO and CO. The resulting gas stream can be utilized for energy recovery, recycled for carbon enrichment of solids, or used as an inert gas in the reactor. Similarly, by separating non-condensable gases from condensable vapors, a CO / CO stream can be prepared for use as an inert gas in, for example, a reactor system or a cooling system.

[0496] Other variations are premised on the recognition that the principles of the carbon enrichment step can be applied to any feedstock to which it is desired to add carbon.

[0497] In some embodiments, a batch or continuous process for producing a high carbon bio-reagent comprises: (a) providing a solids stream comprising a carbon-containing material; (b) providing a gas stream comprising a condensable carbon-containing vapor, a non-condensable carbon-containing gas, or a mixture of a condensable carbon-containing vapor and a non-condensable carbon-containing gas; (c) passing the gas stream through the solid stream under suitable conditions to form a carbon-containing product having an increased carbon content relative to the carbon-containing material.

[0498] In some embodiments, the starting carbon-containing material is pyrolyzed biomass or torrefied biomass. The gas stream can be obtained during an integrated process to provide the carbon-containing material. Alternatively, the gas stream can be obtained from a separate processing of the carbon-containing material. The gas stream, or a portion thereof, can be obtained from an external source (e.g., a sawmill oven). Mixtures of gas streams from various sources are possible, as well as mixtures of carbon-containing materials.

[0499] In some embodiments, the process further comprises repeating the process to recycle or reuse the gas stream to further increase the carbon or energy content of the carbon-containing product. In some embodiments, the process further comprises performing the process to recycle or reuse the gas stream to increase the carbon or energy content of another feedstock different from the carbon-containing material.

[0500] In some embodiments, the process further includes introducing the gas stream into a separation unit configured to produce at least first and second output streams, the gas streams comprising a mixture of condensable carbon-containing vapors and non-condensable carbon-containing gases. The first and second output streams can be separated based on relative volatility, relative polarity, or any other characteristic. The gas streams can be obtained from separate processing of carbon-containing materials.

[0501] In some embodiments, the process further comprises repeating the process to recycle or reuse the gas stream to further increase the carbon content of the carbon-containing product. In some embodiments, the process further comprises performing the process to recycle or reuse the gas stream to increase the carbon content of another feedstock.

[0502] The carbon-containing product can have an increased total carbon content, a higher fixed carbon content, a higher volatile carbon content, a higher energy content, or any combination thereof, relative to the starting carbon-containing material.

[0503] In a related variation, the high carbon bio-reagent production system comprises: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operable communication with the supplying apparatus and configured to remove moisture contained within the carbon-containing feedstock; (c) a multi-zone reactor disposed in operative communication with the dryer, the multi-zone reactor comprising 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 solids cooler disposed in operable communication with the multi-zone reactor; (e) a material enrichment unit disposed in operable communication with the solids cooler and configured to pass a condensable vapor or a non-condensable gas through the solids to form an enriched solid having an increased carbon content; (f) a high-carbon biological reagent recovery unit disposed in operable communication with the material concentration unit.

[0504] The system may further include a preheating zone disposed in operable communication with the pyrolysis zone. In some embodiments, the dryer is configured as a drying zone within the multi-zone reactor. Each of the zones may be located within a single unit or in separate units. Additionally, a solids cooler may be disposed within the multi-zone reactor.

[0505] In some embodiments, the cooling zone is configured with a gas inlet and the pyrolysis zone is configured with a gas outlet, thereby creating a substantially countercurrent flow of the gas phase relative to the solid phase. In these or other embodiments, the preheating zone or drying zone (or dryer) is configured with a gas outlet, thereby creating a substantially countercurrent flow of the gas phase relative to the solid phase.

[0506] In certain embodiments, the system incorporates a material enrichment unit, the material enrichment unit comprising: (i) a housing having an upper portion and a lower portion; (ii) an inlet at the bottom of the lower portion of the housing configured to carry condensable vapors and non-condensable gases; (iii) an outlet at the top of the upper portion of the housing configured to carry a concentrated gas stream derived from the condensable vapors and non-condensable gases; (iv) a passageway defined between the upper and lower portions of the housing; (v) a transport system following the pathway, the transport system configured to transport a solid, the housing shaped to allow the solid to adsorb condensable vapors or non-condensable gases.

[0507] The present disclosure can produce a variety of compositions useful as high-carbon biological reagents, and products incorporating such reagents. In some variations, the high-carbon biological reagent can be prepared using any of the processes disclosed herein, e.g., (a) providing a carbon-containing feedstock comprising biomass; (b) optionally drying the feedstock to remove moisture contained within the feedstock; (c) optionally degassing the feedstock to remove interstitial oxygen, if any, contained in the feedstock; (d) pyrolyzing the feedstock in a pyrolysis zone in the presence of a substantially inert gas for at least 10 minutes and at a pyrolysis temperature selected from about 250°C to about 700°C, thereby producing high temperature pyrolysis solids, condensable vapors, and non-condensable gases; (e) separating condensable vapors and non-condensable gases from the high temperature pyrolysis solids; (f) cooling the hot pyrolysis solid in a cooling zone in the presence of a substantially inert gas for at least 5 minutes and at a cooling temperature below the pyrolysis temperature, thereby producing a warm pyrolysis solid; (g) cooling the warm pyrolysis solid, thereby producing a cold pyrolysis solid; (h) recovering the high-carbon biological reagent comprising cold pyrolysis solids.

[0508] In some embodiments, the reagent comprises about at least 70%, at least 80%, at least 90%, or at least 95% total carbon by weight on a dry basis. Total carbon includes at least fixed carbon and can further include carbon from volatile materials. In some embodiments, carbon from volatile materials is about at least 5%, at least 10%, at least 25%, or at least 50% of the total carbon present in the high-carbon biological reagent. For example, fixed carbon can be measured using ASTM D3172 and volatile carbon can be measured using ASTM D3175.

[0509] The high-carbon bio-reagent may contain about 10% or less by weight, e.g., about 5% or less by weight, hydrogen on a dry basis. The bio-reagent may contain about 1% or less by weight, e.g., about 0.5% or less by weight, nitrogen on a dry basis. The bio-reagent may contain about 0.5% or less by weight, e.g., about 0.2% or less by weight, phosphorus on a dry basis. The bio-reagent may contain about 0.2% or less by weight, e.g., about 0.1% or less by weight, sulfur on a dry basis.

[0510] Carbon, hydrogen, and nitrogen can be measured, for example, using ASTM D5373 for elemental analysis. Oxygen can be measured, for example, using ASTM D3176. Sulfur can be measured, for example, using ASTM D3177.

[0511] Certain embodiments provide reagents that are substantially free of hydrogen (except for any moisture that may be present), nitrogen, phosphorus, or sulfur, and are essentially carbon plus any ash and moisture that may be present. Thus, some embodiments provide bioreagents that have 100% or less carbon on a dry / ash-free (DAF) basis.

[0512] Generally speaking, feedstocks such as biomass contain non-volatile species, including silica and various metals, that are not readily released during pyrolysis. Of course, ashless feedstocks can also be utilized, in which case there should be no substantial amount of ash in the pyrolysis solids. Ash can be measured, for example, using ASTM D3174.

[0513] Varying amounts of non-combustible materials, such as ash, may be present. The high-carbon biological reagent may include about 10% or less by weight, e.g., about 5%, about 2%, about 1% or less by weight, of non-combustible materials on a dry basis. In certain embodiments, the reagent contains little or essentially no ash or other non-combustible materials. Thus, some embodiments provide essentially pure carbon, including 100% carbon on a dry basis.

[0514] Varying amounts of moisture may be present. Based on total mass, the high-carbon bioreagent may contain at least 1%, 2%, 5%, 10%, 15%, 25%, 35%, 50%, or more by weight of moisture. As intended herein, "moisture" should be interpreted to include any form of water present in the bioreagent, including absorbed moisture, adsorbed water molecules, chemical hydrates, and physical hydrates. The equilibrium moisture content may vary depending on at least the local environment, such as relative humidity. Moisture may also vary during transportation, preparation for use, and other logistics. Moisture can be measured, for example, using ASTM D3173.

[0515] High-carbon bioreagents can have a variety of energy contents, which for the present purposes refers to energy density based on the higher calorific value associated with the total combustion of the bone-dry reagent. For example, high-carbon bioreagents can have an energy content of about at least 11,000 Btu / lb, at least 12,000 Btu / lb, at least 13,000 Btu / lb, at least 14,000 Btu / lb, or at least 15,000 Btu / lb. In certain embodiments, the energy content is about 14,000-15,000 Btu / lb. Energy content can be measured, for example, using ASTM D5865.

[0516] The high-carbon biological reagent can be formed into a powder, such as a coarse or fine powder. For example, the reagent can, in embodiments, be formed into a powder having an average mesh size of about 200 mesh, about 100 mesh, about 50 mesh, about 10 mesh, about 6 mesh, about 4 mesh, or about 2 mesh.

[0517] In some embodiments, the high-carbon biological reagent is formed into a structure comprising compressed, bonded, or agglomerated particles. The starting material for forming these bodies can be a powder form of the reagent, such as an intermediate obtained by particle size reduction. The bodies can be formed by mechanical pressing or other forces, optionally with the use of binders or other means to agglomerate the particles together.

[0518] In some embodiments, the high-carbon bio-reagent is produced in the form of a structure whose structure is substantially derived from the source material. For example, a source chip can produce a product chip of high-carbon bio-reagent. Or, a source cylinder can produce a high-carbon bio-reagent cylinder, which can be somewhat smaller but otherwise maintain the basic structure and geometry of the starting material.

[0519] High-carbon biological reagents according to the present disclosure can be produced or formed into objects having a minimum dimension of at least about 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, or more. In various embodiments, the minimum or maximum dimension can be a length, width, or diameter.

[0520] Other variations of the present disclosure relate to the incorporation of additives into the process, into the product, or both. In some embodiments, the high-carbon biological reagent includes a process additive that is incorporated during the process. In these or other embodiments, the reagent includes a product additive that is introduced into the reagent after the process.

[0521] In some embodiments, the high-carbon biological reagent comprises, on a dry basis: 70% by weight or more of total carbon; 5% by weight or less of hydrogen; 1% by weight or less of nitrogen; 0.5 wt. % or less of phosphorus; 0.2% by weight or less of sulfur; and an additive selected from a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof.

[0522] The additives may be selected from, but are in no way limited to, magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorospar, bentonite, calcium oxide, lime, and combinations thereof.

[0523] In some embodiments, the high-carbon biological reagent comprises, on a dry basis: 70% by weight or more of total carbon; 5% by weight or less of hydrogen; 1% by weight or less of nitrogen; 0.5 wt. % or less of phosphorus; 0.2% by weight or less of sulfur; and an additive selected from an acid, a base, or a salt thereof.

[0524] The additive may be selected from, but is in no way limited to, sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, or combinations thereof.

[0525] In certain embodiments, the high carbon biological reagent comprises, on a dry basis: 70% by weight or more of total carbon; 5% by weight or less of hydrogen; 1% by weight or less of nitrogen; 0.5 wt. % or less of phosphorus; 0.2% by weight or less of sulfur; a first additive selected from a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof; a second additive selected from an acid, a base, or a salt thereof; The first additive is different from the second additive.

[0526] The first additive may be selected from magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorospar, bentonite, calcium oxide, lime, or a combination thereof, and the second additive may be independently selected from sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, or a combination thereof.

[0527] Certain high carbon bioreagents consist essentially, on a dry basis, of carbon, hydrogen, nitrogen, phosphorus, sulfur, a non-combustible material, and an additive selected from magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, fluorospar, bentonite, calcium oxide, lime, or combinations thereof.

[0528] Certain high-carbon biological reagents consist essentially, on a dry basis, of carbon, hydrogen, nitrogen, phosphorus, sulfur, a non-combustible material, and an additive selected from sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, or combinations thereof.

[0529] The amount of additive (or total additives) can vary widely, such as from about 0.01% to about 25% by weight, including about 0.1%, about 1%, about 5%, about 10%, or about 20% by weight. It will be appreciated, therefore, that when relatively large amounts of additive, such as greater than about 1% by weight, are incorporated, the energy content calculated based on the total reagent weight (including additives) will be reduced. Furthermore, in various embodiments, the high-carbon biological reagent with additives can have an energy content of about at least 11,000 Btu / lb, at least 12,000 Btu / lb, at least 13,000 Btu / lb, at least 14,000 Btu / lb, or at least 15,000 Btu / lb.

[0530] The above discussion regarding product form also applies to embodiments incorporating additives, and indeed certain embodiments incorporate additives as binders, fluxing agents, or other modifiers to improve final properties for particular applications.

[0531] In some embodiments, the majority of the carbon contained in the high-carbon bio-reagent is classified as renewable carbon. In some embodiments, substantially all of the carbon is classified as renewable carbon. There may be specific market mechanisms (e.g., renewable identification numbers, tax credits, etc.) whereby value is attributed to the renewable carbon content within the high-carbon bio-reagent.

[0532] In certain embodiments, the fixed carbon can be classified as non-renewable carbon (e.g., from coal), while the volatile carbon, which can be added separately, can be renewable carbon to increase not only the energy content but also the renewable carbon value.

[0533] The high-carbon bioreagents produced as described herein are useful for a wide variety of carbonaceous products. They may themselves be desirable market products. The high-carbon bioreagents provided herein are associated with lower levels of impurities, reduced process emissions, and improved sustainability (including higher renewable carbon content) compared to the state of the art.

[0534] In variations, the product comprises any of the high-carbon biological reagents obtainable by the disclosed processes or described in the compositions set forth herein, or any portion, combination, or derivative thereof.

[0535] Generally speaking, high-carbon bio-reagents can be combusted to produce energy (including electricity and heat), partially oxidized, gasified, or steam reformed to produce syngas, utilized for their adsorption or absorption properties, utilized for their reactive properties during metal refining (such as reduction of metal oxides, such as in accordance with the present disclosure) or other industrial processes, or utilized for their material properties in carbon steel and various other metal alloys. Essentially, high-carbon bio-reagents can be utilized in any market application of carbon-based commodities or advanced materials, including specialized applications that are developed.

[0536] Prior to suitability or actual use in any product application, the disclosed high-carbon bioreagents can be analyzed, measured, and optionally modified (such as by additives) in a variety of ways. Some potentially important properties beyond chemical composition and energy content include density, particle size, surface area, microporosity, absorption, adsorption, binding capacity, reactivity, desulfurization activity, and basicity, to name a few.

[0537] Products or materials into which these high carbon bioreagents can be incorporated include, but are in no way limited to, carbon-based blast furnace addition products, carbon-based taconite pellet addition products, ladle addition carbon-based products, metcoke carbon-based products, coal replacement products, carbon-based coking products, carbon breeze products, fluidized bed carbon-based feedstocks, carbon-based furnace addition products, injectable carbon-based products, pulverized carbon-based products, stoker carbon-based products, carbon electrodes, or activated carbon products.

[0538] Use of the disclosed high carbon bio-reagents in metal production can reduce slag, increase overall efficiency, and reduce life cycle environmental impact. Thus, embodiments of the present disclosure are particularly suited for metal processing and production.

[0539] Some variations of the present disclosure utilize high-carbon bioreagents as carbon-based blast furnace addition products. A blast furnace is a type of metallurgical furnace used in smelting to produce industrial metals, such as (but not limited to) iron. Smelting is a form of extractive metallurgy, and its primary use is to produce metals from their ores. Smelting uses heat and chemical reducing agents to break down the ore. Carbon, or carbon monoxide derived from the carbon, removes oxygen from the ore, leaving behind the elemental metal.

[0540] The reducing agent can include, or consist essentially of, a high-carbon bioreagent. In a blast furnace, the high-carbon bioreagent, ore, and often limestone can be continuously fed through the top of the furnace, while air (optionally oxygen-enriched) is blown into the bottom of the chamber, resulting in a chemical reaction occurring throughout the furnace as the material moves downward. The end products are typically molten metal and slag phases removed from the bottom, and flue gases exiting the top of the furnace. The downward flow of ore in contact with the upward flow of hot, carbon monoxide-enriched gas is a countercurrent process.

[0541] Carbon quality in a blast furnace is measured by its resistance to degradation. The role of carbon as a permeable medium is important in economical blast furnace operation. Carbon decomposition varies with location in the blast furnace and involves a combination of reaction with CO, H, or O, and attrition of carbon particles against each other and other components of the charge. Decomposed carbon particles can cause clogging and reduced performance.

[0542] The coke reactivity test is a highly regarded measure of the performance of carbon in a blast furnace. The test has two components: the Coke Reactivity Index (CRI) and the Coke Strength after Reaction (CSR). Carbon-based materials with low CRI values ​​(high reactivity) and high CSR values ​​are preferred for better blast furnace performance. CRI can be determined as received according to any suitable method known in the art, for example, by ASTM method DS341.

[0543] In some embodiments, the high carbon bioreagent provides a carbon product with properties suitable for direct introduction into a blast furnace.

[0544] The strength of the high-carbon bio-reagent can be determined by any suitable method known in the art, for example, by drop crush test or CSR test. In some embodiments, the high-carbon bio-reagent, when optionally blended with another carbon source, provides a final carbon product having a CSR of at least about 50%, 60%, or 70%. The combined product can also provide a final coke product with a reactivity suitable for combustion in a blast furnace. In some embodiments, the product has a CRI such that the high-carbon bio-reagent is suitable for use as an additive or replacement for metcoal, metcoke, coke breeze, foundry coke, or injectable coal.

[0545] Some embodiments use an additive in an amount sufficient to provide a high-carbon bio-reagent that, when added to another carbon source (e.g., coke) that has insufficient CRI or CSR for use as a blast furnace product, provides a composite product with sufficient CRI or CSR for use in a blast furnace. In some embodiments, the additive is present in an amount sufficient to provide a high-carbon bio-reagent with a CRI of at most about 40%, 30%, or 20%.

[0546] In some embodiments, an additive selected from alkaline earth metals, or their oxides or carbonates, is introduced during or after the process of producing the high-carbon bioreagent. For example, calcium, calcium oxide, calcium carbonate, magnesium oxide, or magnesium carbonate can be introduced as an additive. Adding these compounds before, during, or after pyrolysis can increase the reactivity of the high-carbon bioreagent in the blast furnace. These compounds can result in stronger materials, i.e., higher CSR, thereby improving blast furnace efficiency. In addition, additives such as those selected from alkaline earth metals, or their oxides or carbonates, can result in lower emissions (e.g., SO2).

[0547] In some embodiments, the high-carbon bioreagent not only has a high fixed carbon content, as described above, but also contains a significantly higher proportion of volatile carbon. Volatile materials may be desirable for metal oxide reduction because they are expected to have better mass transport to the metal oxide at lower temperatures. Compared to fossil fuel-based products such as coke, the high-carbon bioreagent may have sufficient strength and more fixed volatile carbon, which results in greater reactivity.

[0548] In some embodiments, the blast furnace replacement product is a high-carbon bioreagent according to the present disclosure, comprising at least about 55% by weight carbon, at most about 0.5% by weight sulfur, at most about 8% by weight non-combustible materials, and a calorific value of at least about 11,000 Btu / lb. In some embodiments, the blast furnace replacement product further comprises at most about 0.035% by weight phosphorus, about 0.5% by weight to about 50% by weight volatiles, and optional additives. In some embodiments, the blast furnace replacement product comprises about 2% by weight to about 15% by weight dolomite, about 2% by weight to about 15% by weight dolomitic lime, about 2% by weight to about 15% by weight bentonite, or about 2% by weight to about 15% by weight calcium oxide. In some embodiments, the blast furnace replacement product has dimensions substantially in the range of about 1 cm to about 10 cm.

[0549] In some embodiments, the high-carbon bioreagent according to the present disclosure is useful as a foundry coke replacement product. Foundry coke is generally characterized by a carbon content of at least about 85% by weight, a sulfur content of about 0.6% by weight, a volatile matter content of at most about 1.5% by weight, an ash content of at most about 13% by weight, a moisture content of at most about 8% by weight, a phosphorus content of at most about 0.035% by weight, a CRI value of about 30, and dimensions ranging from about 5 cm to about 25 cm.

[0550] Some variations of the present disclosure utilize high-carbon bioreagents as carbon-based taconite pellet addition products. The ore used in iron and steel production is iron oxide. The primary iron oxide ores include hematite, limonite (also known as brown ore), taconite, and magnetite, a black ore. Taconite is a low-grade but important ore that contains both magnetite and hematite. The iron content of taconite is generally 25% to 30% by weight. Blast furnaces require at least about 50% iron-containing ore by weight for efficient operation. Iron ore can undergo beneficiation processes, including crushing, screening, tumbling, flotation, and magnetic separation. Refined ore is often concentrated to over 60% iron and formed into pellets before transport.

[0551] For example, taconite can be crushed into a fine powder and combined with a binder such as bentonite clay and limestone. For example, pellets about one centimeter in diameter containing about 65% iron by weight can be formed. The pellets are calcined to oxidize the magnetite to hematite. The pellets are durable and ensure that the blast furnace charge remains porous enough to allow heated gases to pass through and react with the pelletized ore.

[0552] The taconite pellets can be fed into a blast furnace to produce iron, as described above with respect to blast furnace addition products. In some embodiments, a high-carbon bioreagent is introduced into the blast furnace. In these or other embodiments, the high-carbon bioreagent is incorporated into the taconite pellets themselves. For example, beneficiated taconite ore powder can be mixed with a high-carbon bioreagent and a binder, rolled into small bodies, and then fired until hard. In such embodiments, taconite-carbon pellets having the appropriate composition can be conveniently introduced into a blast furnace without the need for a separate carbon source.

[0553] Some variations of the present disclosure utilize high carbon bioreagents as ladle-added carbon-based products. A ladle is a vessel used to transport and pour out molten metal. A casting ladle is used to pour molten metal into a mold to produce a casting. A transfer ladle is used to transfer large quantities of molten metal from one process to another. A processing ladle is used for processes that occur in a ladle to change some aspect of the molten metal, such as converting cast iron to ductile iron by adding various elements to the ladle.

[0554] The high-carbon bio-reagent can be introduced into any type of ladle, but carbon can be added to the treatment ladle in a suitable amount based on the target carbon content. The carbon injected into the ladle can be in the form of a fine powder for good mass transfer of the carbon into the final composition. In some embodiments, the high-carbon bio-reagent according to the present disclosure, when used as a ladle addition product, has a minimum dimension of about 0.5 cm, e.g., about 0.75 cm, about 1 cm, about 1.5 cm, or more.

[0555] In some embodiments, the high carbon bio-reagent according to the present disclosure is useful as a ladle addition carbon additive, for example, in basic oxygen furnace or electric arc furnace facilities where ladle addition of carbon is used (e.g., added to ladle carbon during steel production).

[0556] In some embodiments, the ladle-added carbon additive further comprises up to about 5% by weight manganese, up to about 5% by weight calcium oxide, or up to about 5% by weight dolomitic lime.

[0557] Direct-reduced iron (DRI), also known as sponge iron, is produced from the direct reduction of iron ore (in lump, pellet, or fine form) with a reducing gas traditionally produced from natural gas or coal. The reducing gas can be synthesis gas, a mixture of hydrogen and carbon monoxide, which acts as a reducing agent. The high-carbon bioreagents provided herein can be converted into a gas stream containing CO to act as a reducing agent to produce direct-reduced iron.

[0558] Iron nuggets are a high-quality steelmaking and iron casting feed material. Iron nuggets are essentially all iron and carbon, with little gangue (slag) and low levels of metallic residues. They are a premium-grade pig iron product with excellent transport and handling characteristics. The carbon contained in the iron nuggets or any portion thereof can be the high-carbon bioreagent provided herein. Iron nuggets can be produced by reducing iron ore in a rotary hearth furnace using the high-carbon bioreagent as a reducing agent and energy source.

[0559] Some variations of the present disclosure utilize high-carbon bioreagents as metallurgical coke carbonaceous products. Metallurgical coke, also known as "met" coke, is a carbonaceous material typically produced by destructive distillation of various blends of bituminous coal. The final solid is unfused carbon, referred to as metallurgical coke. As a result of the loss of volatile gases and partial melting, met coke has an open-porous morphology. Met coke has a very low volatile content. However, ash components that were part of the original bituminous coal feedstock remain encapsulated in the resulting coke. Met coke feedstock is available in a wide range of sizes, from fine powder to basketball-sized chunks. Purity can range from at least about 86 to at most about 92% fixed carbon by weight.

[0560] Metallurgical coke is used wherever high quality, tough, and resilient wear carbon is required. Applications include, but are not limited to, conductive flooring, friction materials (e.g., carbon linings), foundry coatings, foundry carbon risers, corrosion materials, drilling applications, reducing agents, heat treatment agents, ceramic packing media, electrolytic processes, and oxygen scavenging.

[0561] Metcoke can be characterized as having a heating value of about 10,000-14,000 Btu / lb and an ash content of about 10% by weight or greater. Thus, in some embodiments, a metcoke-replacement product comprises a high-carbon bioreagent according to the present disclosure that contains at least about 80%, 85%, or 90% by weight carbon, at most about 0.8% by weight sulfur, at most about 3% by weight volatiles, at most about 15% by weight or less ash, at most about 13% by weight moisture, and at most about 0.035% by weight phosphorus. When used as a metcoke-replacement product, the high-carbon bioreagent according to the present disclosure can have a size range of, for example, about 2 cm to about 15 cm.

[0562] In some embodiments, the metcoke replacement product further comprises additives such as chromium, nickel, manganese, magnesium oxide, silicon, aluminum, dolomite, fluorospar, calcium oxide, lime, dolomitic lime, bentonite, and combinations thereof.

[0563] Some variations of the present disclosure utilize high-carbon bio-reagents as coal-substitute products. Any process or system that uses coal can, in principle, be adapted to use high-carbon bio-reagents.

[0564] In some embodiments, the high-carbon bio-reagent is combined with one or more coal-based products to form a composite product that has a higher rank than the coal-based product or that has lower emissions when combusted than the pure coal-based product.

[0565] For example, low-rank coal, such as sub-bituminous coal, can be used in applications that normally require high-rank coal products, such as bituminous coal, by combining a selected amount of a high-carbon bio-reagent according to the present disclosure with the low-rank coal product. In other embodiments, the rank of a mixed coal product (e.g., a combination of multiple coals of different ranks) can be improved by combining the mixed coal with an amount of high-carbon bio-reagent. The amount of high-carbon bio-reagent mixed with the coal product can vary depending on the rank of the coal product, the properties of the high-carbon bio-reagent (e.g., carbon content, heat value, etc.), and the desired rank of the final combined product.

[0566] For example, anthracite coal is generally characterized as having at least about 80% by weight carbon, about 0.6% by weight sulfur, about 5% by weight volatile matter, a maximum of about 15% by weight ash, a maximum of about 10% by weight moisture, and a heating value of about 12,494 Btu / lb. In some embodiments, the anthracite coal substitute product is a high-carbon bioreagent comprising at least about 80% by weight carbon, at most about 0.6% by weight sulfur, at most about 15% by weight ash, and a heating value of at least about 12,000 Btu / lb.

[0567] In some embodiments, the high-carbon bioreagent is useful as a thermal coal replacement product. Thermal coal products are generally characterized by high sulfur levels, high phosphorus levels, high ash content, and a heating value of up to about 15,000 Btu / lb. In some embodiments, the thermal coal replacement product is a high-carbon bioreagent containing at most about 0.5% sulfur by weight, at most about 4% ash by weight, and a heating value of at least about 12,000 Btu / lb.

[0568] Some variations of the present disclosure utilize a high-carbon bioreagent as a carbon-based coking product. Any coking process or system can be adapted to use a high-carbon bioreagent to produce coke or use it as a coke feedstock.

[0569] In some embodiments, the high-carbon bioreagent is useful as a thermal coal or coke substitute product. For example, the thermal coal or coke substitute product can consist essentially of a high-carbon bioreagent comprising at least about 50% by weight carbon, at most about 8% by weight ash, at most about 0.5% by weight sulfur, and a heating value of at least about 11,000 Btu / lb. In other embodiments, the thermal coke substitute product comprises a high-carbon bioreagent comprising at least about 50% by weight carbon, at most about 8% by weight ash, at most about 0.5% by weight sulfur, and a heating value of at least about 11,000 Btu / lb. In some embodiments, the thermal coke substitute product further comprises between about 0.5% by weight and about 50% by weight volatile matter. The thermal coal or coke substitute product can comprise between about 0.4% by weight and about 15% by weight moisture.

[0570] In some embodiments, the high-carbon bioreagent is useful as a petroleum (pet) coke or calcined pet coke replacement product. Calcined pet coke is generally characterized by having at least about 66% by weight carbon, at most 4.6% by weight sulfur, at most about 5.5% by weight volatiles, at most about 19.5% by weight ash, and at most about 2% by weight moisture, and may be about 3 mesh or smaller in size. In some embodiments, the calcined pet coke replacement product is a high-carbon bioreagent containing at least about 66% by weight carbon, at most about 4.6% by weight sulfur, at most about 19.5% by weight ash, and at most about 2% by weight moisture, and is about 3 mesh or smaller in size.

[0571] In some embodiments, the high-carbon bioreagent is useful as a coking carbon replacement carbon (e.g., co-fired with metallurgical coal in a coking furnace). In one embodiment, the coking carbon replacement product is a high-carbon bioreagent containing at least about 55% by weight carbon, at most about 0.5% by weight sulfur, at most about 8% by weight non-combustible material, and a heating value of at least about 11,000 Btu / lb. In some embodiments, the coking carbon replacement product contains from about 0.5% by weight to about 50% by weight volatile materials or additives.

[0572] Some variations of the present disclosure utilize a high-carbon bioreagent as a carbon breeze product, which may have a very fine particle size, such as 6 mm, 3 mm, 2 mm, 1 mm, or smaller. In some embodiments, a high-carbon bioreagent according to the present disclosure is useful as a coke breeze replacement product. Coke breeze is generally characterized as having a maximum dimension of at most about 6 mm, a carbon content of at least about 80% by weight, 0.6-0.8% by weight sulfur, 1%-20% by weight volatiles, up to about 13% by weight ash, and up to about 13% by weight moisture. In some embodiments, a coke breeze replacement product is a high-carbon bioreagent according to the present disclosure comprising at least about 80% by weight carbon, at most about 0.8% by weight sulfur, at most about 20% by weight volatiles, at most about 13% by weight ash, at most about 13% by weight moisture, and a maximum dimension of about 6 mm.

[0573] In some embodiments, the high carbon bioreagent is useful as a carbon breeze replacement product, for example, during taconite pellet production or in steelmaking processes.

[0574] Some variations utilize high-carbon bioreagents as feedstocks for various fluidized beds or as a substitute product for fluidized bed carbonaceous feedstocks. The carbon can be used in fluidized beds for total combustion, partial oxidation, gasification, steam reforming, etc. The carbon can be converted to synthesis gas for various downstream uses, including the production of energy (e.g., combined heat and power) or liquid fuels (e.g., methanol or Fischer-Tropsch diesel).

[0575] In some embodiments, high carbon bio-reagents according to the present disclosure are useful, for example, as fluidized bed coal replacement products in fluidized bed furnaces where coal is used (e.g., for process heat or energy generation).

[0576] Some variations utilize a high-carbon bioreagent as the carbon-based furnace addition product. Coal-based carbon-furnace addition products are generally characterized as having high sulfur levels, high phosphorus levels, and high ash content, which contribute to the degradation of metal products and cause air pollution. In some embodiments, the carbon-furnace addition surrogate product containing the high-carbon bioreagent contains at most about 0.5% by weight sulfur, at most about 4% by weight ash, at most about 0.03% by weight phosphorus, and a maximum dimension of about 7.5 cm. In some embodiments, the carbon-furnace addition surrogate product contains between about 0.5% by weight and about 50% by weight volatiles and between about 0.4% by weight and about 15% by weight moisture.

[0577] In some embodiments, the high carbon bio-reagent is useful as a furnace-added carbon additive, for example, in basic oxygen furnaces or electric arc furnace facilities, wherever furnace-added carbon is used. For example, furnace-added carbon can be added to scrap steel during steel production in electric arc furnace facilities. In electric arc furnace applications, high purity carbon is desirable so that impurities are not returned to the process after early removal.

[0578] In some embodiments, the furnace-added carbon additive is a high-carbon bioreagent containing at least about 80% by weight carbon, at most about 0.5% by weight sulfur, at most about 8% by weight non-combustible material, and a calorific value of at least about 11,000 Btu / lb. In some embodiments, the furnace-added carbon additive further contains up to about 5% by weight manganese, up to about 5% by weight fluorite, about 5% to about 10% by weight dolomite, about 5% to about 10% by weight dolomitic lime, or about 5% to about 10% by weight calcium oxide.

[0579] Some variations utilize high-carbon bio-reagent as a stoker furnace carbon-based product. In some embodiments, high-carbon bio-reagent according to the present disclosure is useful, for example, as a stoker coal replacement product in stoker furnace facilities where coal is used (e.g., for process heat or energy generation).

[0580] Some variations utilize a high-carbon bioreagent as the injectable (e.g., finely divided) carbon-based material. In some embodiments, the high-carbon bioreagent is useful as an injection-grade calcined pet coke replacement product. Injection-grade calcined pet coke is generally characterized as having at least about 66% by weight carbon, about 0.55 to about 3% by weight sulfur, up to about 5.5% by weight volatiles, up to about 10% by weight ash, and up to about 2% by weight moisture, and is about 6 mesh or smaller in size. In some embodiments, the calcined pet coke replacement product is a high-carbon bioreagent containing at least about 66% by weight carbon, at most about 3% by weight sulfur, at most about 10% by weight ash, and at most about 2% by weight moisture, and is about 6 mesh or smaller in size.

[0581] In some embodiments, the high carbon bio-reagent is useful in any application where injectable carbon is used (e.g., injected into the slag or ladle during steel production), for example, as an injectable carbon replacement product in basic oxygen furnace or electric arc furnace facilities.

[0582] In some embodiments, the high-carbon bio-reagent is useful, for example, as a fine carbon replacement product whenever pulverized coal is used (e.g., for process heat or energy generation). In some embodiments, the fine carbon replacement product comprises up to about 10 percent calcium oxide.

[0583] Some variations utilize high-carbon bioreagents as carbon addition products for metal production. In some embodiments, the high-carbon bioreagents according to the present disclosure are useful as carbon addition products for the production of carbon steel or another metal alloy containing carbon. Coal-based late-stage carbon addition products are generally characterized as having high sulfur levels, high phosphorus levels, and high ash, as well as high mercury levels that degrade metal quality and contribute to air pollution. In some embodiments of the present disclosure, the carbon addition products include at most about 0.5% by weight sulfur, at most about 4% by weight ash, at most about 0.03% by weight phosphorus, a minimum dimension of about 1-5 mm, and a maximum dimension of about 8-12 mm.

[0584] Some variations utilize high-carbon bio-reagents within carbon electrodes. In some embodiments, the high-carbon bio-reagents are useful as electrode (e.g., anode) materials suitable for use in, for example, aluminum production.

[0585] Other applications of high-carbon bio-reagents in carbon electrodes include batteries, fuel cells, capacitors, and other energy storage or energy delivery devices. For example, in lithium-ion batteries, high-carbon bio-reagents can be used on the anode side to intercalate lithium. In these applications, carbon purity and low ash content can be very important.

[0586] Some variations of the present disclosure utilize high-carbon bioreagents as catalyst supports. Carbon is a known catalyst support in a wide range of catalytic chemical reactions, such as the synthesis of mixed alcohols from syngas using sulfided cobalt-molybdenum metal catalysts supported on a carbon phase, or iron-based catalysts supported on carbon for the Fischer-Tropsch synthesis of higher hydrocarbons from syngas.

[0587] Some variations utilize high-carbon bioreagents as activated carbon products. Activated carbon is used in a wide variety of liquid- and gas-phase applications, including water treatment, air purification, solvent vapor recovery, food and beverage processing, and pharmaceuticals. For activated carbon, the porosity and surface area of ​​the material are generally important. The high-carbon bioreagents provided herein, in various embodiments, can provide superior activated carbon products due to: (i) greater surface area than fossil-fuel-based activated carbons; (ii) carbon renewable potential; (iii) the vascularity of the biomass feedstock in combination with additives allows for better penetration / distribution of additives to enhance pollutant control; and (iv) less inert material (ash), resulting in greater reactivity.

[0588] In the above description of market applications for high-carbon bio-reagents, it should be recognized that the applications described are not exclusive or exhaustive. Thus, a high-carbon bio-reagent described as suitable for one type of carbon product may, in various embodiments, be suitable for any other application described. These applications are exemplary only, and there are other applications for high-carbon bio-reagents.

[0589] Additionally, in some embodiments, the same physical material can be used in multiple market processes, either in an integrated manner or sequence. Thus, for example, a high-carbon bioreagent used as a carbon electrode or activated carbon can, at the end of its useful life as a performance material, be introduced into a combustion process for energy value or into a metal fabrication process (e.g., reduction of metal ores), etc.

[0590] Some embodiments may use bio-reagents due to their reactive / adsorbent properties as well as fuels. For example, bio-reagents injected into an exhaust stream may be suitable for removing contaminants and subsequently combusting the bio-reagent particles and possibly the contaminants to generate energy and thermally destroy or chemically oxidize the contaminants.

[0591] Compared to conventional fossil fuel-based products, high-carbon bio-reagents can be associated with significant environmental and product use advantages. High-carbon bio-reagents can be not only environmentally superior, but also functionally superior from a processing standpoint, for example, due to higher purity.

[0592] For some embodiments of metal production, production of bioreagents by the disclosed process reduces CO, CO, NO, and CO2 emissions compared to the coking of coal-based products required to prepare them for use in metal production. x This can result in significantly lower emissions of CO2, SO2, and harmful air pollutants.

[0593] The use of high carbon bioreagents instead of coal or coke also significantly reduces environmental emissions of SO2, hazardous air pollutants, and mercury.

[0594] Additionally, due to the purity of these high carbon bio-reagents (including low ash content), the disclosed bio-reagents have the potential to reduce slag and increase production capacity in batch metal fabrication processes.

[0595] Variations utilizing coal and other non-biomass feedstocks While the most significantly beneficial environmental impact occurs when the pyrolysis feedstock is exclusively biomass, the processes and systems herein can be adapted to non-biomass feedstocks, or mixtures of biomass and other feedstocks. It will be further recognized that in some cases, the pyrolysis step is not necessary, for example, if the selected solid feedstock (e.g., coal) has sufficient properties such as carbon content or reactivity, or if the feedstock has been previously pyrolyzed.

[0596] For example, the solid carbonaceous feedstock can be selected from biomass, lignite, coal, coal-like carbon deposits, oil shale, asphalt, petroleum coke, scrap tires, recycled plastic, recycled paper, construction waste, demolition waste, or combinations thereof.

[0597] When the solid carbonaceous feedstock is or comprises biomass, the biomass feedstock may be softwood chips, hardwood chips, timber harvest residues, tree branches, tree stumps, leaves, bark, sawdust, corn, corn stover, wheat, wheat straw, rice, rice straw, sugarcane, sugarcane bagasse, sugarcane straw, energy sugarcane, sugarbeet, sugarbeet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass , fruits, fruit shells, fruit stems, fruit peels, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable peels, vegetable seeds, grape pomace, 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 trimmings, food packaging, construction or demolition waste, railroad ties, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof.

[0598] It should be noted that "solid carbonaceous feedstock" means that the feedstock is in substantially solid form, but may contain liquids such as water, oil, low molecular weight lignin, tar, hydrocarbons, and the like.

[0599] In some embodiments, the solid carbonaceous feedstock is a mixture of biomass and coal, for example, about 1% to about 99% biomass with the remainder being coal. In particular embodiments, the solid carbonaceous feedstock is coal.

[0600] Some variations are: (a) providing a solid carbonaceous feedstock; (b) pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) optionally chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) optionally, continuously or periodically recovering a reagent during step (d) or eventually after step (d), wherein the recovered reagent is activated carbon.

[0601] Some variations are: (a) providing a solid carbonaceous feedstock; (b) optionally, pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) optionally, continuously or periodically recovering a reagent during step (d) or eventually after step (d), wherein the recovered reagent is activated carbon.

[0602] Step (b) is often performed when the solid carbonaceous feedstock is a mixture of biomass and coal. When the solid carbonaceous feedstock is coal, step (b) is often not performed unless the coal is lignite or other low-rank coal where pyrolysis improves its suitability for downstream processing.

[0603] Some variations are: (a) providing a solid carbonaceous feedstock; (b) optionally, pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) optionally chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) continuously or periodically recovering a reagent during step (d) or eventually after step (d), wherein the recovered reagent is activated carbon.

[0604] Some variations are: a first reactor configured to pyrolyze a solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; a second reactor configured to react the reagent with the selected reactant, thereby producing a reducing gas, the second reactor optionally configured to continuously, periodically, or eventually remove activated carbon from the second reactor; optionally a third reactor configured to chemically reduce the selected metal oxide in the presence of a reducing gas, thereby producing a reduced form of the selected metal oxide; Optionally, the system further comprises one or more heating units in thermal communication with the first reactor, the second reactor, or the third reactor (if present), wherein the one or more heating units are configured to oxidize the pyrolysis off-gas, thereby generating heat.

[0605] Some variations are (a) providing a solid carbonaceous feedstock; (b) optionally, pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) recovering a metal product comprising a reduced form of the selected metal oxide; (g) optionally, continuously or periodically during step (d) or finally after step (d), recovering a reagent, wherein the recovered reagent is activated carbon.

[0606] Some variations are: (a) providing a solid carbonaceous feedstock; (b) optionally, pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) separating hydrogen from the reducing gas, optionally wherein the hydrogen is separated by one or more separation techniques selected from pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation; (f) recovering renewable hydrogen products, including hydrogen; (g) optionally, continuously or periodically during step (d) or finally after step (d), recovering a reagent, wherein the recovered reagent is activated carbon.

[0607] Some variations are: (a) providing a solid carbonaceous feedstock; (b) optionally, pyrolyzing the solid carbonaceous feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) optionally oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the reagent with the selected reactant, thereby generating a reducing gas; (e) optionally chemically reducing the selected metal oxide in the presence of the reducing gas from step (d), thereby producing a reduced form of the selected metal oxide; (f) continuously or periodically recovering a reagent during step (d) or eventually after step (d), wherein the recovered reagent is activated carbon.

[0608] This detailed description refers to multiple embodiments of the disclosure and non-limiting examples of how the disclosure may be realized and practiced. Other embodiments that do not provide all of the features and advantages described herein may be utilized without departing from the spirit and scope of the disclosure. The disclosure incorporates routine experimentation and optimization of the methods and systems described herein. Such modifications and variations are deemed to be within the scope of the disclosure, as defined by the claims.

[0609] All publications, patents, and patent applications cited in this specification are herein incorporated by reference in their entirety, as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference herein.

[0610] While the methods and steps described above show certain events occurring in a particular order, those skilled in the art will recognize that the order of certain things can be changed and that such changes are in accordance with variations of the present disclosure. Furthermore, some of the steps may be performed simultaneously in a parallel process where possible, or may be performed sequentially.

[0611] Therefore, to the extent there are variations of this disclosure that are within the spirit of or equivalents of the disclosure found in the appended claims, it is intended that this patent cover those variations as well. The disclosure is to be limited only by the claims. [Example]

[0612] Example 1: Reduction of iron ore using reducing gas derived from a bioreagent. Douglas fir (Pseudotsuga menziesii) in the form of wood chips is provided as the biomass feedstock, with the average size of the wood chips being about 25 millimeters long, about 25 millimeters wide, and about 5 millimeters thick.

[0613] Pulverized iron ore is supplied in the form of taconite, a low-grade siliceous iron ore containing 20-30% magnetite (Fe3O4) by weight. Taconite is primarily mined in the Mesabi Iron Range of Minnesota and the Marquette Iron Range of Michigan, USA.

[0614] The biomass feedstock is pyrolyzed in a continuous pyrolysis reactor at a pyrolysis temperature of about 600°C and a pyrolysis residence time of about 30 minutes. The pyrolysis pressure is about 1 bar (atmospheric pressure) under an inert gas consisting essentially of N2. There are solid and steam outputs from the pyrolysis reactor. The solid output is the carbon-containing bioreagent. The steam output is the pyrolysis off-gas that is combusted to generate heat.

[0615] The bioreagent is fed into a reducing gas generation reactor, which is fed with water vapor. The reducing gas generation reactor is operated at a temperature of about 800°C, a pressure of about 1 bar, a gas residence time of about 5 seconds, and a solid residence time of about 30 minutes. The reducing gas generation reactor is heated using heat generated from pyrolysis off-gas combustion. The vapor output from the reducing gas generation reactor is the reducing gas.

[0616] The reducing gas and taconite are fed to the chemical reduction reactor. Granulated taconite is fed to the chemical reduction reactor using a solids inlet port. Reduction gas containing H2 and CO is metered into the chemical reduction reactor from the reduction gas generation reactor using a steam inlet port. Steam flows cocurrently with the solids stream. The chemical reduction reactor is operated at a reduction temperature of approximately 900°C, a reduction pressure of approximately 5 bar (due to pressurized reducing gas), and a reduction residence time of approximately 1 hour. In the reduction reactor, Fe3O4 is reduced to a mixture of FeO and Fe (FeO is in a lower oxidation state than Fe3O4) by reaction with H2 and CO. The steam output from the chemical reduction reactor is a reduction off-gas containing water and carbon dioxide. The solid output from the chemical reduction reactor is a metal product containing Fe and possibly FeO that is not completely reduced to iron metal.

[0617] Example 2: Reduction of iron ore using reducing gas derived from bioreagents with activated carbon generation. Douglas fir (Pseudotsuga menziesii) in the form of wood chips is provided as the biomass feedstock, with the average size of the wood chips being about 25 millimeters long, about 25 millimeters wide, and about 5 millimeters thick.

[0618] Pulverized iron ore is provided in the form of taconite, a low-grade siliceous iron ore containing 20-30% magnetite (Fe3O4) by weight. Taconite is primarily mined in the Mesabi Iron Range of Minnesota and the Marquette Iron Range of Michigan, USA.

[0619] The biomass feedstock is pyrolyzed in a continuous pyrolysis reactor at a pyrolysis temperature of about 600°C and a pyrolysis residence time of about 30 minutes. The pyrolysis pressure is about 1 bar (atmospheric pressure) under an inert gas consisting essentially of N2. There are solid and steam outputs from the pyrolysis reactor. The solid output is the carbon-containing bioreagent. The steam output is the pyrolysis off-gas that is combusted to generate heat.

[0620] The bioreagent is fed into a reduction gas generation reactor, which is fed with water vapor. The reduction gas generation reactor is operated at a temperature of about 800°C, a pressure of about 1 bar, a gas residence time of about 5 seconds, and a solid residence time of about 30 minutes. The reduction gas generation reactor is heated using heat generated from the pyrolysis off-gas combustion. The steam output from the reduction gas generation reactor is the reduc...

Claims

1. (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a carbon-containing bio-reagent and a pyrolysis off-gas; (c) oxidizing the pyrolysis off-gas, thereby producing heat; (d) reacting the bio-reagent with a selected reactant, thereby producing a reducing gas; (e) chemically reducing the selected metal oxide in the presence of the reducing gas, thereby producing a reduced form of the selected metal oxide; (f) continuously or periodically recovering said bio-reagent during step (d), thereby producing a recovered bio-reagent that is activated carbon.

2. 10. The process of claim 1, wherein step (b) is carried out at a pyrolysis temperature of at least 250°C to at most 1250°C.

3. 3. The process of claim 1 or 2, wherein step (b) is carried out for a pyrolysis time of from 10 seconds to at most 24 hours.

4. 10. The process of claim 1, wherein step (d) is carried out at a reaction temperature of at least 300°C to at most 1200°C.

5. 10. The process of claim 1, wherein step (d) is carried out for a reaction time of at least 1 second to at most 1 hour.

6. 10. The process of claim 1, wherein step (e) is carried out at a reduction temperature of at least 500°C to at most 2000°C.

7. 2. The process of claim 1, wherein step (e) is carried out for a reduction time of at least 30 minutes and at most 48 hours.

8. 10. The process of claim 1, wherein the bioreagent comprises at least 50% carbon by weight.

9. 10. The process of claim 1, wherein the bioreagent comprises at least 50% by weight of fixed carbon.

10. 10. The process of claim 1, wherein the process further comprises a water gas shift reaction, thereby increasing the hydrogen content of the reducing gas.

11. 11. The process of claim 1 or 10, wherein the process further comprises separating hydrogen from the reducing gas and recovering the hydrogen.

12. 12. The process of claim 11, wherein the process further comprises separating the hydrogen from the reducing gas, and wherein the separating is accomplished using pressure swing adsorption, molecular sieve membrane separation, or cryogenic distillation.

13. 10. The process of claim 1, wherein the selected reactant in step (d) is water.

14. 10. The process of claim 1, wherein the selected reactant in step (d) is oxygen, and the oxygen is contained in air, pure oxygen, concentrated oxygen, ozone, or a combination thereof.

15. 10. The process of claim 1, wherein the selected reactant in step (d) comprises a combination of water and oxygen.

16. 2. The process of claim 1, wherein the pyrolysis off-gas is partially oxidized, thereby producing additional reducing gas and the heat, and step (e) further comprises chemically reducing the selected metal oxides in the presence of the additional reducing gas.

17. 10. The process of claim 1, wherein the process further comprises converting the pyrolysis off-gas into additional reducing gas.

18. The process of claim 1, wherein at least 1% by weight of the biological reagent produced in step (b) is recovered as the activated carbon in step (f).

19. The process of claim 1, wherein at least 50% by weight of the fixed carbon in the bioreagent produced in step (b) is recovered as the activated carbon in step (f).

20. 20. The process of claim 19, wherein essentially all of the fixed carbon in the bio-reagent produced in step (b) is recovered as the activated carbon in step (f).

21. 21. The process of claim 20, wherein at least 50% by weight of the volatile carbon within the bio-reagent produced in step (b) is directed toward the reducing gas.

22. 22. The process of any one of claims 18 to 21, wherein the activated carbon is characterized by an iodine value of at least 2000.

23. The activated carbon is １４ C / １２ 23. The process of any one of claims 18 to 22, characterized by a renewable carbon content of at least 90% as determined from C isotope ratio measurements.

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