Biocarbon pellets with adjustable grindability index

Abstract

In some variations, the present invention provides bio-carbon pellets comprising 35%-99% by weight bio-reagent, the bio-reagent comprising at least 60% by weight carbon on a dry basis, 0%-35% by weight moisture, and 1%-30% by weight binder, the bio-carbon pellets being characterized by an adjustable Hardgrove Grindability Index (HGI) of about 30 to about 120, as shown in the examples. The pellet HGI is adjustable by controlling process conditions and the pellet binder. The binder can be an organic binder or an inorganic binder. The carbon is: 14 C / 12 It is renewable, as determined from measurements of the C isotope ratio. Many processes for making and using biocarbon pellets are described. Applications for biocarbon pellets include pulverized coal boilers, furnaces for making metals such as iron or silicon, and gasifiers for producing reducing gases.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 139,875, filed January 21, 2021, which is incorporated by reference herein in its entirety.

[0002] The present disclosure relates generally to highly grindable pellets containing biocarbon and biocarbon pellets containing reactive mitigating agents, and processes for making and using such pellets. [Background technology]

[0003] Biomass is a term used to describe biologically produced or living matter. The chemical energy contained in biomass comes from solar energy using the natural process of photosynthesis. This is the process by which plants take carbon dioxide and water from their surroundings and convert them into sugars, starch, cellulose, hemicellulose, and lignin using energy from sunlight. Of all renewable energy sources, biomass is unique in that it is effectively stored solar energy. Furthermore, biomass is the only renewable source of carbon.

[0004] Carbon-based reagents can in principle be produced from virtually any material that contains carbon. Carbonaceous materials typically include fossil resources such as natural gas, petroleum, coal, and lignite, as well as renewable resources such as lignocellulosic biomass and various carbon-enriched waste materials. Due to the rising economic, environmental, and social costs associated with fossil resources, it is preferable to utilize renewable biomass to produce carbon-based reagents.

[0005] Various conversion technologies exist for biomass feedstocks to carbonaceous materials. Pyrolysis is a process for thermal conversion of solid materials in the complete absence of oxidizing agents (air or oxygen) or with such limited supply 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 steam residence times favor the production of solids. High temperatures and longer residence times increase biomass conversion to syngas, while moderate temperatures and short steam residence times are generally optimal for producing liquids. Historically, slow pyrolysis of wood has been carried out in large piles, in simple batch processes, and without emissions controls. Traditional charcoal production techniques are not only energy inefficient, but also highly polluting.

[0006] In many industrial applications, it is desirable to replace coal by providing high carbon pellets obtained from biomass pyrolysis. In many applications, pellets are preferred over powders (e.g., pyrolyzed, isolated biomass particles) due to shipping, storage, and safety advantages. Ultimately, pellets may need to be converted back to powder, or at least smaller bodies, at some point. Thus, pellet grindability is often a critical parameter that impacts operational and capital costs.

[0007] In some cases, the pellets need to be crushed or pulverized into a powder, such as when a boiler or gasifier utilizes a fluidized bed or a suspension of carbon particles. Another example is pulverized carbon injection into a blast furnace to reduce metal ores to metals. In these cases, high pellet grindability is desirable, but not too high that the pellets break down during transport and handling. In other cases, it is desirable to feed the pellets themselves to a process, such as a metal manufacturing process. In these cases, lower grindability may be desirable, since some pellet strength may be required to support the bed of material in the reactor. Different technologies have different pellet grindability requirements.

[0008] Hardgrove Grindability Index ("HGI") is a measure of the grindability of a material such as biomass or coal. The HGI parameter for coal is important in power applications such as pulverized coal boilers where the coal is crushed and burned in suspension, and in metals production, for example, where pulverized coal is injected through a lance into a blast furnace to replace coke to reduce iron ore to metallic iron.

[0009] Biomass-derived materials (and biomass itself) typically perform poorly and do not grind as well as most coals. Raw biomass is particularly difficult to grind into a powder. In addition, pellets derived from pyrolyzed biomass are traditionally difficult to grind.

[0010] There is therefore a need for biocarbon pellets that can be economically ground for a variety of commercial applications. It would be particularly desirable to be able to tailor the HGI to suit a particular application, such as combustion, metal production, or gasification. Summary of the Invention

[0011] The present invention addresses the aforementioned needs in the art.

[0012] In some variations, the present invention provides a bio-carbon pellet comprising: (a) about 35% to about 99% by weight of a bioreagent, the bioreagent containing at least about 60% by weight carbon on a dry basis; (b) about 0% to about 35% by weight of water; (c) about 1% by weight to about 30% by weight of a binder; The bio-carbon pellets are characterized by a Hardgrove Crushability Index of at least 30.

[0013] In some embodiments, the bioreagent contains at least about 70%, at least about 80%, or at least about 90% carbon by weight on a dry basis.

[0014] In some embodiments, the bioreagent contains, on a dry basis, at least about 50% fixed carbon, at least about 75% fixed carbon, or at least about 90% fixed carbon by weight.

[0015] In some biocarbon pellets, the carbon is 14 C / 12 At least 50% renewable, as determined from measurements of the C isotope ratio. For example, carbon is 14 C / 12 As determined from C isotope ratio measurements, the carbon may be at least 80%, at least 90%, or at least 95% renewable. In certain embodiments, the carbon is 14 C / 12 It is fully reproducible, as determined from C isotope ratio measurements.

[0016] In some embodiments, the biological reagent contains, on a dry basis, about 75% to about 94% carbon by weight, about 3% to about 15% oxygen by weight, and about 1% to about 10% hydrogen by weight.

[0017] In some biocarbon pellets, the biocarbon pellets include, for example, about 1% to about 30% moisture by weight, e.g., about 5% to about 15% moisture by weight, about 2% to about 10% moisture by weight, or about 0.1% to about 1% moisture by weight.

[0018] In some biocarbon pellets, the biocarbon pellets include about 2% to about 25% binder by weight, about 5% to about 20% binder by weight, or about 1% to about 5% binder by weight.

[0019] The binder may be an organic binder or an inorganic binder. In some embodiments, the binder is or includes a renewable material. In some embodiments, the binder or a portion thereof may be partially oxidized or combusted.

[0020] In various embodiments, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, Gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled shingle, recycled tires, derivatives thereof, or any combination of the foregoing.

[0021] In some embodiments, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, derivatives thereof, or any combination of the foregoing, hi certain embodiments, the binder is an optionally crosslinked thermoplastic starch.

[0022] In some embodiments, the thermoplastic or crosslinked starch can be a reaction product of starch and a polyol. The reaction product can be, for example, a glycosidic bond or glycosidic linkage, which is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group (which may or may not be another carbohydrate). For example, a glycosidic bond can be formed between a hemiacetal or hemiketal group of a sugar (or a molecule derived from a sugar) and a hydroxyl group of a polyol. A substance that contains a glycosidic bond is a glycoside, although the disclosure is not limited to this reaction. The polyol can be selected from ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, erythritol, xylitol, sorbitol, or combinations thereof. Glycerol is a typical polyol. The thermoplastic or crosslinking chemical reaction can be catalyzed by an acid or by a base. The acid can be selected from, for example, formic acid, acetic acid, lactic acid, citric acid, oxalic acid, uronic acid, glucuronic acid, or combinations thereof. The base can be selected from, for example, ammonia, ammonium hydroxide, sodium hydroxide, or combinations thereof.

[0023] In some embodiments, the binder reduces the reactivity of the bio-carbon pellets compared to otherwise comparable bio-carbon pellets without the binder. Reactivity can refer to thermal or chemical reactivity (or both). In the case of thermal reactivity, the bio-carbon pellets can have lower self-heating compared to otherwise comparable bio-carbon pellets without the binder. Chemical reactivity can be reactivity with oxygen, water, hydrogen, carbon monoxide, metals (e.g., iron), or combinations thereof.

[0024] The binder may be pore-filled within the bio-reagent of the bio-carbon pellet. Alternatively or additionally, the binder may be disposed on a surface of the bio-carbon pellet.

[0025] The biocarbon pellets can have a Hardgrove Crushability Index of at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. In some embodiments, the Hardgrove Crushability Index is from about 30 to about 50, or from about 40 to about 70.

[0026] The biocarbon pellets can be characterized by a pellet durability index of at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%. The biocarbon pellets can be characterized by a pellet durability index of less than 99%, less than 95%, or less than 90%.

[0027] Another variation of the present invention is a process for producing bio-carbon pellets, comprising: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a bio-reagent, the bio-reagent containing at least about 50% by weight carbon and at least about 5% by weight moisture; (c) mechanically treating the biological reagent, thereby generating a plurality of carbon-containing particles; (d) combining the carbon-containing particles with a binder to form a carbon-binder mixture; (e) subsequent to or simultaneously with step (d), pelletizing the carbon-binder mixture, thereby producing bio-carbon pellets; (f) optionally, at least partially drying the bio-carbon pellets; The process provides that the biocarbon pellets are characterized by an average Hardgrove Grindability Index of at least 30.

[0028] In some process embodiments, the bio-reagent contains at least about 70%, at least about 80%, or at least about 90% carbon by weight on a dry basis.

[0029] In some process embodiments, the bioreagent contains, on a dry basis, at least about 50% fixed carbon, at least about 75% fixed carbon, or at least about 90% fixed carbon by weight.

[0030] Carbon is carbon 14 C / 12 It may be at least 50%, at least 90%, at least 95%, or completely renewable, as determined from C isotope ratio measurements.

[0031] In some processes, the bioreagent contains, on a dry basis, about 75% to about 94% carbon by weight, about 3% to about 15% oxygen by weight, and about 1% to about 10% hydrogen by weight.

[0032] In some processes, the bioreagent contains at least about 10%, 15%, 20%, 25%, 30%, 35%, or 40% by weight of water in step (b). In some embodiments, step (c), step (d), or step (e) is performed at a lower moisture content than that of step (b).

[0033] When step (f) is performed, the drying may result in a lower moisture content than that of step (c), step (d), or step (e).

[0034] In some processes, step (f) occurs after step (e). In other embodiments, step (f) is integrated with step (e).

[0035] In some processes, the biological reagents are not dried during step (c). In some embodiments, the biological reagents are not dried during step (d). In some embodiments, the biological reagents are not dried during step (e).

[0036] The biocarbon pellets may contain about 1% to about 30% moisture by weight, for example, about 5% to about 15% moisture by weight, about 2% to about 10% moisture by weight, or about 0.1% to about 1% moisture by weight.

[0037] In some processes, step (b) is carried out at a pyrolysis temperature selected from about 250°C to about 1250°C, for example from about 300°C to about 700°C.

[0038] In some processes, step (b) is carried out for a pyrolysis time selected from about 10 seconds to about 24 hours.

[0039] Step (c) can utilize, for example, a mechanical processing device selected from a hammer mill, an extruder, an attrition mill, a disk mill, a pin mill, a ball mill, a cone crusher, a jaw crusher, or a combination thereof.

[0040] In some processes, steps (c) and (d) are combined.

[0041] The biocarbon pellets may contain about 2% to about 25% by weight of a binder, such as about 5% to about 20% by weight of a binder, or about 1% to about 5% by weight of a binder. The binder may be organic or inorganic.

[0042] In various processes, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled gravel, recycled tires, derivatives thereof, or any combination of the foregoing.

[0043] In some processes, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, derivatives thereof, or any combination of the foregoing. In certain embodiments, the binder is an optionally crosslinked thermoplastic starch.

[0044] For example, the thermoplastic or crosslinked starch can be a reaction product of starch and a polyol. The polyol can be selected from ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, erythritol, xylitol, sorbitol, or a combination thereof. Glycerol is a typical polyol. The thermoplastic or crosslinking chemical reaction can be catalyzed by an acid or a base. The acid can be selected from formic acid, acetic acid, lactic acid, citric acid, oxalic acid, uronic acid, glucuronic acid, or a combination thereof.

[0045] In some processes, the binder reduces the reactivity of the bio-carbon pellets compared to otherwise comparable bio-carbon pellets without the binder. Reactivity can refer to thermal or chemical reactivity (or both). In the case of thermal reactivity, the bio-carbon pellets can have lower self-heating compared to otherwise comparable bio-carbon pellets without the binder. Chemical reactivity can be reactivity with oxygen, water, hydrogen, carbon monoxide, metals (e.g., iron or silicon), or combinations thereof.

[0046] The binder may be pore-filled within the bio-reagent of the bio-carbon pellet. Alternatively or additionally, the binder may be disposed on a surface of the bio-carbon pellet.

[0047] Step (e) may utilize a pelletizing device selected from an extruder, a ring die pellet mill, a flat die pellet mill, a roll compactor, a roll briquetter, a wet agglomerate mill, a dry agglomerate mill, or a combination thereof.

[0048] In some processes, steps (d) and (e) are combined.

[0049] In various process embodiments, the Hardgrove Grindability Index is controlled to be at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. For example, the Hardgrove Grindability Index can be controlled in the process to be selected from about 30 to about 50, about 40 to about 50, about 50 to about 70, or about 40 to about 70.

[0050] In some processes, the biocarbon pellets are characterized by a pellet durability index of at least 80%, at least 90%, or at least 95%.

[0051] In some embodiments, the process includes preselecting a hardgrove grindability index, adjusting process conditions based on the preselected hardgrove grindability index, and achieving within ±20% of the preselected hardgrove grindability index for the biocarbon pellets, where the adjusted process conditions include adjusting one or more of pyrolysis temperature, pyrolysis time, mechanical treatment conditions, pelletizing conditions, binder type, binder concentration, binding conditions, and drying. The process of certain embodiments can achieve within ±10%, or within ±5%, of the preselected hardgrove grindability index for the biocarbon pellets.

[0052] Some variations are biocarbon pellets, (a) about 35% to about 99% by weight of a bioreagent, the bioreagent containing at least about 60% by weight carbon on a dry basis; (b) about 0% to about 35% by weight of water; (c) about 1% by weight to about 30% by weight of a reactivity moderator; the mitigating agent reduces the reactivity of the bio-carbon pellets relative to otherwise equivalent bio-carbon pellets that do not include the mitigating agent; The reactivity is selected from one or more of thermal reactivity, chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0053] In some embodiments, the bio-reagent contains at least 70% carbon by weight on a dry basis. The bio-reagent can contain at least about 50% fixed carbon by weight on a dry basis.

[0054] The bioreagent may contain, on a dry basis, about 75% to about 94% by weight carbon, about 3% to about 15% by weight oxygen, and about 1% to about 10% by weight hydrogen.

[0055] In some embodiments, the biocarbon pellets contain between about 1% and about 30% moisture by weight.

[0056] In some embodiments, the carbon is 14 C / 12 At least 50% renewable as determined from C isotope ratio measurements. In certain embodiments, the carbon is 14 C / 12 It is fully reproducible, as determined from C isotope ratio measurements.

[0057] In some bio-carbon pellets, the bio-carbon pellets include from about 2% to about 25% by weight of the reactive mitigating agent. The bio-carbon pellets can include, for example, from about 5% to about 20% by weight, or from about 1% to about 5% by weight of the reactive mitigating agent.

[0058] The binder can be organic or inorganic. The reactive moderator can be a renewable material such as cellulose or lignin.

[0059] In some embodiments, the reactive moderator is capable of being partially oxidized or combusted.

[0060] The reactive modifier may be selected from starch, thermoplastic starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, Gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled gravel, recycled tires, derivatives thereof, or any combination of the foregoing.

[0061] In some embodiments, the reactive modifier is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, derivatives thereof, or any combination of the foregoing.

[0062] In certain embodiments, the reactive modifier is an optionally crosslinked thermoplastic starch. For example, the thermoplastic starch can be a reaction product of starch and a polyol. The polyol can be selected from ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, erythritol, xylitol, sorbitol, or combinations thereof. The reaction product can be formed from a reaction catalyzed by an acid, such as (but not limited to) formic acid, acetic acid, lactic acid, citric acid, oxalic acid, uronic acid, glucuronic acid, or combinations thereof, or by a base.

[0063] In some biocarbon pellets, the reactivity mitigating agent reduces the thermal reactivity of the biocarbon pellet. For example, the biocarbon pellet can be characterized by lower self-heating compared to an otherwise equivalent biocarbon pellet that does not include the reactivity mitigating agent. "Self-heating" refers to a biocarbon pellet that undergoes a spontaneous exothermic reaction in the absence of any external ignition, at a relatively low temperature and in an oxidizing atmosphere, to increase the internal temperature of the biocarbon pellet. In some embodiments, the biocarbon composition is characterized as non-self-heating when subjected to a self-heating test according to Manual of Tests and Criteria, Seventh revised edition 2019, United Nations, Page 375, 33.4.6 Test N.4: "Test method for self-heating substances".

[0064] In some biocarbon pellets, the reactivity mitigating agent reduces the chemical reactivity of the biocarbon pellets with oxygen, water, hydrogen, carbon monoxide, metals (such as iron), or combinations thereof.

[0065] In some embodiments, the reactivity mitigated by the reactivity mitigating agent is at least two of thermal reactivity, chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0066] In certain embodiments, the reactivity mitigated by the reactivity mitigating agent is at least three, at least four, at least five, or all six of the following: thermal reactivity, chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0067] In some embodiments, the reactivity mitigated by the reactivity mitigating agent is at least (i) thermal reactivity, and (ii) chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0068] In certain embodiments, the reactivity mitigated by the reactivity mitigating agent is at least (i) thermal reactivity, and (ii) at least two, at least three, or at least four of the following: chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0069] In some biocarbon pellets, the reactive mitigating agent is loaded into pores within the bio-reagent of the biocarbon pellet. In other biocarbon pellets, the reactive mitigating agent is disposed on a surface of the biocarbon pellet. In yet other biocarbon pellets, the reactive mitigating agent is loaded into pores within and disposed on a surface of the bio-reagent of the biocarbon pellet.

[0070] The reactive mitigating agent can function as a binder to adjustably control the Hard Grove Crushability Index of the biocarbon pellets, in some embodiments, the biocarbon pellets are characterized by a Hard Grove Crushability Index of at least 30, e.g., from about 30 to about 50, or from about 40 to about 70. [Brief description of the drawings]

[0071] [Figure 1] FIG. 1 is a simplified block flow diagram of a process for producing bio-carbon pellets from biomass feedstock according to some embodiments.

[0072] [Diagram 2] Photograph of bio-carbon pellets according to some embodiments.

[0073] [Diagram 3] 1 is a data sheet showing the Hardgrove Grindability Index (HGI) for the biocarbon pellets of Example 1, showing HGI=30.

[0074] [Figure 4] FIG. 1 is a data sheet showing the composition, Hardgrove Crushability Index (HGI), and other properties for the biocarbon pellets of Example 2, where HGI=40.

[0075] [Diagram 5] FIG. 13 is a data sheet showing the composition, Hardgrove Crushability Index (HGI), and other properties for the biocarbon pellets of Example 3, where HGI=45.

[0076] [Figure 6] FIG. 14 is a data sheet showing the composition, Hardgrove Crushability Index (HGI), and other properties for the biocarbon pellets of Example 4, where HGI=49.

[0077] [Figure 7] FIG. 14 is a data sheet showing the composition, Hardgrove Crushability Index (HGI), and other properties for the biocarbon pellets of Example 5, where HGI=71.

[0078] [Figure 8]FIG. 13 is a data sheet showing the Hardgrove Grindability Index (HGI) for the biocarbon pellets of Example 6, where HGI=117. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] The description enables one skilled in the art to make and use the invention and describes several embodiments, adaptations, variations, alternatives, and uses of the invention. These and other embodiments, features, and advantages of the invention 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.

[0080] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0081] 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.

[0082] The term "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 that means that a specified claim element is essential, but that other claim elements may be added and still form a construct within the scope of the claim.

[0083] As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim. When the phrase "consist of" (or variations thereof) appears in a section in the body of a claim rather than immediately following the preamble, the phrase limits only the elements recited in that section and does not exclude other elements from the claim as a whole. As used herein, the phrase "consisting essentially of" limits the scope of the claim to those specified elements or method steps, in addition to those that do not materially affect the basic and novel characteristics of the claimed subject matter.

[0084] With respect to the terms "comprising," "consisting of," and "consisting essentially of," when one of these three terms is used herein, the subject matter disclosed and claimed herein can include the use of either of the other two terms. Thus, in some embodiments not expressly stated otherwise, any instance of "comprising" can be replaced by "consisting of," or alternatively, by "consisting essentially of."

[0085] As used herein, unless expressly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or." Unless the word "or" is expressly limited in reference to a list of two or more items to mean only one item exclusively from the other items, the use of "or" in such a list should be interpreted to include (a) any one item in the list, (b) all items in the list, or (c) any combination of items in the list. As used herein, a phrase "and / or," such as "A and / or B," refers to A alone, B alone, and both A and B. Where the context permits, singular or plural terms can also include the plural or singular terms, respectively.

[0086] For the purpose of enabling technical disclosure, various explanations, hypotheses, theories, speculations, assumptions, etc. are disclosed. The present invention does not depend on any of these being true in reality. None of the explanations, hypotheses, theories, speculations, or assumptions in this detailed description should be construed as limiting the scope of the present invention in any way.

[0087] For the present purposes, "biogenic" is intended to mean a material (feedstock, product, or intermediate) that contains elements such as carbon that are renewable on time scales of months, years, or decades. Non-biogenic materials may be non-renewable or may be renewable on time scales of centuries, millennia, millions of years, or even longer geological time scales. Biogenic materials may include a mixture of biological and non-biogenic sources.

[0088] For the present purposes, "reagent" is intended to mean a material in its broadest sense, and a reagent may be a fuel, a chemical, a material, a compound, an additive, a blend component, a solvent, etc. A reagent is not necessarily a chemical reagent that causes or participates in a chemical reaction. A reagent may be a chemical reactant and may, but is not necessarily, consumed in a reaction. A reagent may be a chemical catalyst for a particular reaction. A reagent may cause or participate in adjusting the mechanical, physical, or hydrodynamic properties of a material to which it may be added. For example, a reagent may be introduced into a metal to give it certain strength properties. A reagent may be a substance of sufficient purity (typically carbon purity in the present context) to be used in chemical analysis or physical testing.

[0089] As used herein, "biocarbon pellets" refers to pellets that contain biogenic carbon. The geometry of the pellets can vary widely, as taught herein.

[0090] As used in this application to describe preferred bioreagents, "high carbon" simply means that the bioreagent has a relatively high carbon content compared to the initial feedstock utilized to make the high carbon bioreagent. Typically, a high carbon bioreagent can contain at least about half of its weight as carbon. More typically, a high carbon bioreagent will contain at least 55%, 60%, 65%, 70% or more carbon by weight.

[0091] Notwithstanding the above, the term "high carbon bio-reagent" is used herein for practical purposes to consistently describe materials that may be produced by the disclosed processes and systems in various embodiments. Any limitations on carbon content or any other concentration are to be imputed only by reference to specific embodiments and their equivalents, and not from the term itself. For example, it will be understood that starting materials with very low carbon content that are subjected to the disclosed processes may produce high carbon bio-reagents that are highly enriched in carbon relative to the starting material (high carbon yield), but are nevertheless relatively low in carbon (low purity carbon), such as less than about 50% carbon by weight.

[0092] Some variations are based on optimized pyrolysis of biomass to produce a carbon substrate, mechanical size reduction of the carbon substrate, and the use of binders to agglomerate the carbon substrate to form bio-carbon pellets with adjustable Hardgrove Grindability Index (HGI). The moisture level of the bio-carbon pellets can be optimized to vary the density within the pellets. The ability to tailor the HGI of the bio-carbon pellets is highly beneficial as downstream applications utilizing the bio-carbon pellets (e.g., replacing coal in a boiler) have different HGI requirements.

[0093] Particle size can be measured by a variety of techniques including dynamic light scattering, laser diffraction, image analysis, or sieve separation. Dynamic light scattering is a non-invasive, well-established technique for measuring particle size and size distribution, typically in the submicron range, with the latest techniques measuring down to one nanometer. Laser diffraction is a widely used particle sizing technique for materials sized from hundreds of nanometers to several millimeters. Exemplary dynamic light scattering and laser diffraction instruments for measuring particle size are available from Malvern Instruments Ltd., Worcestershire, UK. Image analysis to estimate particle size and distribution can be performed directly on photomicrographs, scanning electron micrographs, or other images. Finally, sieving is a conventional technique for separating particles by size.

[0094] The present invention addresses two well-known industrial problems: (1) the difficulty of grinding raw biomass, and (2) the difficulty of grinding pellets.

[0095] Particle size reduction is necessary in the context of a wide variety of biorefinery processes for converting biomass (e.g., wood chips) into products. The size reduction step is essential but very energy intensive due to the presence of strong bonds in the naturally occurring cellulose, hemicellulose, and lignin polymers. This problem is particularly acute when small particles are encountered. For example, the energy consumption of hammer mill grinding of biomass increases exponentially as a function of screen mesh size reduction.

[0096] Raw biomass is inferior to pyrolyzed forms of biomass (many of which are described in this patent application) for a wide variety of commercial applications. Once biomass is pyrolyzed into bioreagents, its mechanical properties often do not lend themselves to downstream applications such as blast furnaces or pulverized coal boilers. For that reason, it is often preferable to pelletize the bioreagents into biocarbon pellets. However, once pelletized, the problematic grinding energies discussed above for raw biomass also make it difficult, and often even worse, to convert the pellets into industrial powders. This could potentially be overcome by creating loose agglomerates that are essentially weak pellets, but these agglomerates defeat the purpose of pelletization in many cases where durability of the pellets is required during transportation and plant processing, and sometimes within the reactor itself (e.g., to support the material bed for some period of time prior to reaction). This problem seems almost impossible to solve, since on the one hand pellet durability is desired, but on the other hand pellet grindability is desired. However, the inventors have overcome this problem by discovering biocarbon pellets and a process for making them that have good grindability and adequate durability.

[0097] Furthermore, since there are numerous downstream applications of bio-carbon pellets, each with its own unique requirements, being able to tailor the grindability of the pellets is highly advantageous. The inventors have designed a process and composition that is well suited for tailorably grindable bio-carbon pellets.

[0098] In some variations, the present invention provides a bio-carbon pellet comprising: (a) about 35% to about 99% by weight of a bioreagent, the bioreagent containing at least about 60% by weight carbon on a dry basis; (b) about 0% to about 35% by weight of water; (c) about 1% by weight to about 30% by weight of a binder; The bio-carbon pellets are characterized by a Hardgrove Crushability Index of at least 30.

[0099] In some embodiments, the bio-reagent contains at least about 70%, at least about 80%, or at least about 90% carbon by weight on a dry basis. In various embodiments, the bio-reagent contains about or at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% carbon by weight on a dry basis. These percentages refer to the concentration of total carbon (fixed carbon and volatile carbon) relative to the entire bio-reagent.

[0100] In some embodiments, the bioreagent contains at least about 50% fixed carbon, at least about 75% fixed carbon, or at least about 90% fixed carbon by weight on a dry basis. In various embodiments, the bioreagent contains about or at least about 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95% fixed carbon by weight on a dry basis. These percentages refer to the concentration of fixed carbon relative to the entire bioreagent, not to total carbon. Fixed carbon is total carbon minus volatile carbon.

[0101] In some biocarbon pellets, the carbon is 14 C / 12 At least 50% renewable, as determined from measurements of the C isotope ratio. For example, carbon is 14 C / 12 As determined from C isotope ratio measurements, the carbon may be at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, or at least 99.9% renewable. 14 C / 12 It is fully renewable as determined from measurements of the C isotope ratio. 14 C / 12 The C isotope ratio is measured according to ASTM D6866.

[0102] In certain embodiments, the biological reagent contains, on a dry basis, about 75% to about 94% carbon by weight, about 3% to about 15% oxygen by weight, and about 1% to about 10% hydrogen by weight.

[0103] The moisture present in the biocarbon pellets may be water that is chemically bound to the carbon or binder, water that is physically bound (absorbed or adsorbed) to the carbon or binder, free water present in the water phase that is not chemically or physically bound to the carbon or binder, or a combination thereof. When moisture is desired during the binding process, it is preferred that such moisture be chemically or physically bound to the carbon or binder rather than being free water.

[0104] Various moisture levels may be present in the biocarbon pellets. For example, the biocarbon pellets may contain about 1% to about 30% (e.g., 32%) by weight, such as about 5% to about 15% by weight moisture, about 2% to about 10% by weight moisture, or about 0.1% to about 1% by weight moisture. In some embodiments, the biocarbon pellets contain about 4 to 8% by weight moisture. In various embodiments, the biocarbon pellets contain about, at least about, or at most about 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35% by weight moisture, including all intervening ranges.

[0105] In some market applications, such as agriculture, higher moisture levels are desirable for dust control or other reasons. In other market applications, such as metallurgy, lower moisture levels may be desirable (e.g., 1% moisture by weight, or even lower). Water is present during the process of making biocarbon pellets, but the pellets are then optionally dried. This means that the final biocarbon pellets do not necessarily contain moisture.

[0106] In some biocarbon pellets, the biocarbon pellets include about 2% to about 25% binder by weight, about 5% to about 20% binder by weight, or about 1% to about 5% binder by weight. In various embodiments, the biocarbon pellets include about, at least about, or at most about 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, or 30% binder by weight, including all intervening ranges. In some embodiments, there is an inverse relationship between moisture content and binder concentration.

[0107] The binder can be pore-filled within the bio-reagent of the bio-carbon pellet. Alternatively or additionally, the binder can be disposed on the surface of the bio-carbon pellet. In certain embodiments, the binder completely encapsulates the bio-carbon pellet and forms a surface coating on each pellet. The binder-encapsulated pellets can also contain a binder filled within the pores of the bio-reagent.

[0108] The binder may be an organic binder or an inorganic binder. In some embodiments, the binder is or comprises a renewable material. In some embodiments, the binder is or comprises a biodegradable material. In some embodiments, the binder is capable of being partially oxidized or burned.

[0109] In various embodiments, the binder is selected from starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled gravel, recycled tires, derivatives thereof, or any combination of the foregoing. The binder can be or include a grindable plasticizer.

[0110] In certain embodiments, the binder is selected from starch, thermoplastic starch, crosslinked starch, starch-based polymers (e.g., polymers based on amylose and amylopectin), derivatives thereof, or any combination of the foregoing. The starch can be a nonionic starch, anionic starch, cationic starch, or zwitterionic starch.

[0111] Starch is one of the most abundant biopolymers. It is completely biodegradable, inexpensive, renewable, and easily chemically modified. The ring structure of starch molecules, together with the strong hydrogen bonds, give starch a rigid structure, resulting in highly ordered crystalline and granular regions. Starch in its granular state is generally not suitable for thermoplastic processing. To obtain thermoplastic starch, semicrystalline starch granules can be decomposed by thermal and mechanical forces. Since the melting point of pure starch is significantly higher than its decomposition temperature, plasticizers such as water or glycols can be added. The native crystallinity can then be destroyed by vigorous mixing (shear) at high temperatures resulting in thermoplastic starch. Starch can be plasticized (destroyed) by relatively low levels of other molecules that can hydrogen bond with starch hydroxyl groups, such as water, glycerol, or sorbitol.

[0112] Thermoplastic starch can be chemically modified or blended with other biopolymers to produce stronger, more ductile and resilient bioplastics. For example, starch can be blended with natural and synthetic (biodegradable) polyesters such as polylactic acid, polycaprolactone, or polyhydroxybutyrate. To improve the compatibility of starch / polyester blends, suitable compatibilizers such as poly(ethylene-co-vinyl alcohol) or polyvinyl alcohol can be added. The hydrophilic hydroxyl groups (-OH) of starch can be replaced with hydrophobic reactive groups, such as by esterification or etherification.

[0113] In some embodiments, the starch-containing binder is or comprises crosslinked starch. Various methods for crosslinking starch are known in the art. Starch materials can be crosslinked, for example, under acidic or alkaline conditions after dissolving or dispersing in an aqueous medium. Aldehydes (e.g., glutaraldehyde or formaldehyde) can be used to crosslink starch.

[0114] An example of a crosslinked starch is the reaction product of starch with glycerol or another polyol, such as (but not limited to) ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, erythritol, xylitol, sorbitol, or combinations thereof. The reaction product can be formed from a crosslinking reaction catalyzed by an acid, such as (but not limited to) formic acid, acetic acid, lactic acid, citric acid, oxalic acid, uronic acid, glucuronic acid, or combinations thereof. Inorganic acids, such as sulfuric acid, can also be utilized to catalyze the crosslinking reaction. In some embodiments, the thermoplasticized or crosslinked reaction product can instead be formed from a crosslinking reaction catalyzed by a base, such as (but not limited to) ammonia or sodium borate.

[0115] In some embodiments, the binder is designed to be a water-resistant binder. For example, in the case of starch, the hydrophilic groups can be replaced by hydrophobic groups that better resist water. For example, one or more -OH groups on native starch are C4-C , which imparts hydrophobicity to starch-containing binders. 18 It can be replaced by an alkyl group, such as an alkyl group.

[0116] In some embodiments, the binder serves other purposes such as (but not limited to) moisture retention within the biocarbon pellets and as a food source for microorganisms.

[0117] In some embodiments, the binder reduces the reactivity of the bio-carbon pellets compared to otherwise comparable bio-carbon pellets without the binder. Reactivity can refer to thermal or chemical reactivity (or both). In various embodiments, the binder reduces the reactivity of the bio-carbon pellets by at least 1%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% compared to otherwise comparable bio-carbon pellets without the binder.

[0118] In the case of thermal reactivity, the bio-carbon pellets can have low self-heating compared to otherwise comparable bio-carbon pellets that do not contain a binder. "Self-heating" refers to the bio-carbon pellets undergoing a spontaneous exothermic reaction in the absence of any external ignition, at a relatively low temperature and in an oxidizing atmosphere, to increase the internal temperature of the bio-carbon pellets.

[0119] Chemical reactivity can refer to the reactivity of carbon with oxygen, water, hydrogen, carbon monoxide, metals (e.g., iron), or combinations thereof. Chemical reactivity can be associated with reactions to, for example, CO, CO2, H2O, pyrolysis oil, and heat. For example, a chemical reaction between carbon and oxygen can result in the formation of CO or CO2. A chemical reaction between carbon and water can result in the formation of CO, H2, or CH4. A chemical reaction between carbon and hydrogen can result in the formation of CH4 or alkyl radicals (e.g., CH3). A chemical reaction between carbon and metals can result in the formation of metal carbides. While some of the reactions may ultimately be desirable in the ultimate application of the biocarbon pellets, it may be advantageous to slow the chemical reactions or mitigate the reactivity in order to better control the desired conversion at the optimal time and place.

[0120] Optionally, the carbon-containing pellets include one or more additives (not necessarily binders), such as inorganic bentonite clay, limestone, starch, cellulose, lignin, or acrylamide. When lignin is used as a binder or other additive, the lignin can be obtained from the same biomass feedstock used in the pyrolysis process. For example, the starting biomass feedstock can be subjected to a lignin extraction step to remove some amount of lignin for use as a binder or additive.

[0121] Other possible additives include fluxing agents such as inorganic chlorides, inorganic fluorides, or lime. In some embodiments, the additives are selected from acids, bases, or salts thereof. In some embodiments, at least one additive is selected from metals, metal oxides, metal hydroxides, metal halides, or combinations thereof. For example, the additives can be selected from sodium hydroxide, potassium hydroxide, magnesium oxide, hydrogen bromide, hydrogen chloride, sodium silicate, potassium permanganate, magnesium, manganese, aluminum, nickel, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron halides, iron chloride, iron bromide, dolomite, dolomitic lime, fluorspar, fluorospar, bentonite, calcium oxide, lime, or combinations thereof. The additives can be added before, during, or after any one or more steps of the process, including adding to the feedstock itself at any time before or after it is harvested.

[0122] The Hardgrove Grindability Index of the biocarbon pellets may be at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. In some embodiments, the Hardgrove Grindability Index is about 30 to about 50, or about 50 to about 70. ASTM-Standard D409 / D409M for "Standard Test Method for Grindability of Coal by the Hardgrove-Machine Method" is incorporated herein by reference in its entirety. Unless otherwise indicated, all references to Hardgrove Grindability Index or HGI in this disclosure refer to ASTM-Standard D409 / D409M.

[0123] In various embodiments, the Hard Glove Crushability Index is about, at least about, or at most about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 109, 109, 102, 104, 105, 106, 107, 108, 109, 109, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 12 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, or 130.

[0124] The biocarbon pellets can be characterized by a pellet durability index of at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%. The biocarbon pellets can be characterized by a pellet durability index of less than 99%, less than 95%, or less than 90%. Unless otherwise indicated, all references to pellet durability index in this disclosure refer to ISO 17831-1:2015 "Solid biofuels-Determination of mechanical durability of pellets and briquettes-Part 1: Pellets", which is incorporated herein by reference in its entirety. Other laboratory methods for measuring pellet durability include the tumbling box method, the Holmen durability method, and the Stokes hardness method. In all cases, what is being determined is the percentage of the pellet mass that remains as pellets rather than being lost to fragments in the test procedure. Thus, the pellet durability index cannot exceed 100%.

[0125] The pellet durability index is not the opposite of the hardgrove crushability index, and they are not necessarily correlated because the forces experienced during the measurement of the pellet durability index and the hardgrove crushability index are quite different. Typically, a high pellet durability index, such as 96%, 97%, or 98%, is desired to avoid mass loss during pellet transportation. A high HGI, or an optimized HGI, is then beneficial for the intended application (where it is desired to crush the already transported pellets into particles).

[0126] The size and geometry of biocarbon pellets can vary. As used herein, "pellets" refers to aggregated bodies rather than loose powders. The geometry of pellets is not limited to spherical or nearly spherical. Also, in this disclosure, "pellets" is synonymous with "briquettes." The geometry of pellets can be spherical (round or ball shaped), cubic (square), octagonal, hexagonal, honeycomb / honeycomb shaped, elliptical, ovoid, cylindrical, rod shaped, pillow shaped, random, or combinations thereof. For convenience of disclosure, the term "pellets" is used generally for any body containing powders aggregated using a binder.

[0127] Biocarbon pellets can be characterized by an average pellet diameter, which is the true diameter in the case of a sphere, or an equivalent diameter in the case of any other 3D geometry. The equivalent diameter of a non-spherical pellet is the diameter of a sphere of equivalent volume to the actual pellet. In some embodiments, the average pellet diameter is about or at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, or 25 millimeters, including all intervening ranges. In some embodiments, the average pellet diameter is about or at least about 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, or 6500 microns, including all intervening ranges.

[0128] In some embodiments, there are a plurality of bio-carbon pellets that are relatively uniform in size, such as a standard deviation of less than ±100%, less than ±50%, less than ±25%, less than ±10%, or less than ±5% of the average pellet diameter. In other embodiments, there are a wide range of sizes of bio-carbon pellets, as this may be advantageous in some applications.

[0129] Some variations of the present invention are biocarbon pellets comprising: (a) about 35% to about 99% by weight of a bioreagent, the bioreagent containing at least about 60% by weight carbon on a dry basis; (b) about 0% to about 35% by weight of water; (c) about 1% by weight to about 30% by weight of a reactivity moderator; To provide a bio-carbon pellet, wherein the reactivity mitigating agent reduces the reactivity of the bio-carbon pellet compared to an otherwise equivalent bio-carbon pellet that does not include the reactivity mitigating agent.

[0130] In some embodiments, the bio-reagent contains at least 70% carbon by weight on a dry basis. The bio-reagent may contain at least about 50% fixed carbon by weight.

[0131] The bioreagent may contain, on a dry basis, about 75% to about 94% by weight carbon, about 3% to about 15% by weight oxygen, and about 1% to about 10% by weight hydrogen.

[0132] In some embodiments, the biocarbon pellets contain between about 1% and about 30% moisture by weight.

[0133] In some embodiments, the carbon is 14 C / 12 At least 50% renewable as determined from C isotope ratio measurements. In certain embodiments, the carbon is 14 C / 12 It is fully reproducible, as determined from C isotope ratio measurements.

[0134] In some bio-carbon pellets, the bio-carbon pellets include from about 2% to about 25% by weight of the reactive mitigating agent. The bio-carbon pellets can include, for example, from about 5% to about 20% by weight, or from about 1% to about 5% by weight of the reactive mitigating agent.

[0135] The binder may be organic or inorganic. The reactive moderator may be a renewable material.

[0136] In some embodiments, the reactive moderator is capable of being partially oxidized or combusted.

[0137] The reactive modifier may be selected from starch, thermoplastic starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, Gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled gravel, recycled tires, derivatives thereof, or any combination of the foregoing.

[0138] In some embodiments, the reactive modifier is selected from starch, thermoplastic starch, crosslinked starch, starch polymers, derivatives thereof, or any combination of the foregoing.

[0139] In certain embodiments, the reactive modifier is an optionally crosslinked thermoplastic starch. For example, the thermoplastic starch can be a reaction product of starch and a polyol. The polyol can be selected from ethylene glycol, propylene glycol, glycerol, butanediol, butanetriol, erythritol, xylitol, sorbitol, or combinations thereof. The reaction product can be formed from a reaction catalyzed by an acid, such as (but not limited to) formic acid, acetic acid, lactic acid, citric acid, oxalic acid, uronic acid, glucuronic acid, or combinations thereof, or catalyzed by a base.

[0140] In various embodiments, the reactivity mitigating agent reduces the reactivity of the biocarbon pellet by at least 1%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% compared to an otherwise comparable biocarbon pellet without the reactivity mitigating agent. "Self-heating" refers to a biocarbon pellet that undergoes a spontaneous exothermic reaction in the absence of any external ignition, at a relatively low temperature and in an oxidizing atmosphere, to increase the internal temperature of the biocarbon pellet. In some embodiments, the biocarbon pellet is characterized as non-self-heating when subjected to a self-heating test according to Manual of Tests and Criteria, Seventh revised edition 2019, United Nations, Page 375, 33.4.6 Test N.4:"Test method for self-heating substances".

[0141] In some biocarbon pellets, where the reactivity mitigating agent reduces the reactivity of the biocarbon pellets, the reactivity is thermal reactivity, e.g., the biocarbon pellets can be characterized by lower self-heating compared to otherwise equivalent biocarbon pellets that do not include the reactivity mitigating agent.

[0142] Reactivity mitigating agents reduce the reactivity of the bio-carbon pellets. In some bio-carbon pellets, the reactivity is chemical reactivity with oxygen, water, hydrogen, carbon monoxide, metals (such as iron or silicon), or combinations thereof. In this disclosure, metals include metalloids (e.g., silicon, Si).

[0143] In some embodiments, the reactivity mitigated by the reactivity mitigating agent is at least two of thermal reactivity, chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0144] In certain embodiments, the reactivity mitigated by the reactivity mitigating agent is at least three, at least four, at least five, or all six of the following: thermal reactivity, chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0145] In some embodiments, the reactivity mitigated by the reactivity mitigating agent is at least (i) thermal reactivity, and (ii) chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0146] In certain embodiments, the reactivity mitigated by the reactivity mitigating agent is at least (i) thermal reactivity, and (ii) at least two, at least three, or at least four of the following: chemical reactivity with oxygen, chemical reactivity with water, chemical reactivity with hydrogen, chemical reactivity with carbon monoxide, or chemical reactivity with metals.

[0147] In some biocarbon pellets, the reactive mitigating agent is loaded into pores within the bio-reagent of the biocarbon pellet. In other biocarbon pellets, the reactive mitigating agent is disposed on a surface of the biocarbon pellet. In yet other biocarbon pellets, the reactive mitigating agent is loaded into pores within and disposed on a surface of the bio-reagent of the biocarbon pellet.

[0148] The reactive mitigating agent can function as a binder to adjustably control the Hard Grove Grindability Index of the bio-carbon pellets. In some embodiments, the bio-carbon pellets are characterized by a Hard Grove Grindability Index of at least 30, such as from about 30 to about 50 or from about 40 to about 70. Other HGI ranges are disclosed elsewhere herein and are equally applicable to embodiments in which a reactive mitigating agent is used and functions as a binder.

[0149] For example, a binder can be selected that both controllably adjusts the HGI and functions as a reactive mitigation agent. In these cases, it may be desirable to ensure that the binder is not only located on the surface of the biocarbon pellet, but is also dispersed throughout the biocarbon (filling the pores of the biocarbon pellet). The concentration of the binder may be different on the surface compared to the bulk (interior) of the pellet. In some cases, a higher concentration of binder is present in the pellet bulk relative to the surface, while in other cases (e.g., certain embodiments for reduced self-heating pellets) a higher binder concentration at the surface is desired. It is also possible to have two different binders (chemical species), one preferentially in the bulk of the pellet and one preferentially on the surface. In such cases, the bulk binder can be referred to as the binder and the pellet surface agent can be referred to as the pellet reactive mitigation agent. Even in such embodiments, if the binder is added during the pellet manufacturing process, it will be understood that some amount of the binder will be present on the pellet surface. Similarly, if the reactive mitigation agent is coated onto the pellet after it is formed, some amount of the reactive mitigation agent can be expected to penetrate (e.g., by diffusion) into the pellet pores.

[0150] Another variation of the present invention is a process for producing bio-carbon pellets, comprising: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a bio-reagent, the bio-reagent containing at least about 50% by weight carbon and at least about 5% by weight moisture; (c) mechanically treating the biological reagent to generate a plurality of carbon-containing particles; (d) combining the carbon-containing particles with a binder to form a carbon-binder mixture; (e) subsequent to or simultaneously with step (d), pelletizing the carbon-binder mixture, thereby producing bio-carbon pellets; (f) optionally, at least partially drying the bio-carbon pellets; The process provides that the biocarbon pellets are characterized by an average Hardgrove Grindability Index of at least 30.

[0151] In some process embodiments, the bio-reagent contains at least about 70%, at least about 80%, or at least about 90% carbon by weight on a dry basis.

[0152] In some process embodiments, the bioreagent contains at least about 50% by weight fixed carbon, at least about 75% by weight fixed carbon, or at least about 90% by weight fixed carbon.

[0153] Carbon is carbon 14 C / 12 As determined from C isotope ratio measurements, the carbon may be at least 50%, at least 90%, at least 95%, or completely renewable. 14 C / 12 The C isotope ratio is measured according to ASTM D6866.

[0154] In certain processes, the bioreagent contains, on a dry basis, about 75% to about 94% carbon by weight, about 3% to about 15% oxygen by weight, and about 1% to about 10% hydrogen by weight.

[0155] In some processes, the bioreagent contains at least about 10%, 15%, 20%, 25%, 30%, 35%, or 40% moisture by weight in step (b). If the moisture content is more than 40% by weight, biocarbon pellets can still be made, but the pellet density is expected to be low (too low for many applications). In some embodiments, step (c), step (d), or step (e) is performed at a moisture content lower than that of step (b). For example, when step (f) is performed, drying may result in a moisture content lower than that in step (b), and optionally a moisture content lower than that in step (c), step (d), or step (e).

[0156] In some embodiments, step (f) occurs after step (e). In these or other embodiments, step (f) is integrated with step (e). For example, the pelletizing unit can allow water to escape from the pellets as they are being formed. That is, the pelletizing unit can also function as a dryer. In certain embodiments, some amount of drying occurs during pelletizing, and additional drying occurs after pelletizing, for example, in a drying unit or under ambient conditions.

[0157] In some embodiments, the biological reagents are not dried during step (c). In these or other embodiments, the biological reagents are not dried during step (d). In these or other embodiments, the biological reagents are not dried during step (e).

[0158] The biocarbon pellets may contain about 1% to about 30% moisture by weight, for example, about 5% to about 15% moisture by weight, about 2% to about 10% moisture by weight, or about 0.1% to about 1% moisture by weight.

[0159] In some processes, step (b) is carried out at a pyrolysis temperature selected from about 250° C. to about 1250° C., for example, from about 300° C. to about 700° C. In some processes, step (b) is carried out for a pyrolysis time selected from about 10 seconds to about 24 hours. Other possible pyrolysis conditions are described later in this specification.

[0160] Step (c) can utilize, for example, a mechanical processing device selected from a hammer mill, an extruder, an attrition mill, a disk mill, a pin mill, a ball mill, a cone crusher, a jaw crusher, or a combination thereof.

[0161] In some processes, steps (c) and (d) are combined. For example, the binder can be fed directly into a hammer mill or extruder, or other mechanical processing device.

[0162] The carbon-containing particles can be characterized by an average particle size of about 1 micron to about 10 millimeters, e.g., about 10 microns to about 500 microns. In various embodiments, the carbon-containing particles are characterized by an average particle size of about, at least about, or at most about 1 micron, 10 microns, 50 microns, 100 microns, 150 microns, 200 microns, 250 microns, 500 microns, 750 microns, 1 millimeter, 1.5 millimeters, 2 millimeters, 2.5 millimeters, 3 millimeters, 4 millimeters, 5 millimeters, or 10 millimeters, including all intervening ranges.

[0163] The biocarbon pellets may contain about 2% to about 25% by weight of a binder, such as about 5% to about 20% by weight of a binder, or about 1% to about 5% by weight of a binder. The binder may be organic or inorganic.

[0164] The binder may be selected from starch, crosslinked starch, starch polymers, cellulose, cellulose ethers, hemicellulose, methylcellulose, chitosan, lignin, lactose, sucrose, dextrose, maltodextrin, banana flour, wheat flour, wheat starch, soy flour, corn flour, wood flour, coal tar, coal fines, metcoke, asphalt, coal tar pitch, petroleum pitch, bitumen, pyrolysis tar, Gilsonite, bentonite clay, borax, limestone, lime, wax, vegetable wax, baking soda, baking powder, sodium hydroxide, potassium hydroxide, iron ore concentrate, silica fume, gypsum, Portland cement, guar gum, polyvidone, polyacrylamide, polylactide, phenol-formaldehyde resin, vegetable resin, recycled gravel, recycled tires, derivatives thereof, or any combination of the foregoing. In certain processes, the binder is selected from starch, crosslinked starch, starch polymers, derivatives thereof, or any combination of the foregoing.

[0165] Step (e) may utilize a pelletizing device selected from an extruder, a ring die pellet mill, a flat die pellet mill, a roll compactor, a roll briquetter, a wet agglomerate mill, a dry agglomerate mill, or a combination thereof.

[0166] In some processes, steps (d) and (e) are integrated. For example, the binder can be introduced directly into a pelletizing unit. When steps (d) and (e) are performed separately, the binder is mixed with the carbon-containing particles to form a carbon-binder mixture prior to introducing such mixture into a unit configured to pelletize the carbon-binder mixture.

[0167] In some embodiments of the present invention, biocarbon pellets are utilized as starting materials for making smaller objects, and may also be referred to as biocarbon pellets, since "pellets" does not limit the geometric shape. For example, initial biocarbon pellets with an average pellet diameter of 10 mm can be made. These initial biocarbon pellets can then be crushed using various mechanical means (e.g., using a hammer mill). The crushed pellets can be separated according to size, such as by screening. In this manner, smaller biocarbon pellets can be produced, for example, having an average pellet diameter of about, at least about, or at most about 50, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 3000, 4000, or 5000 microns. The average pellet diameter of the smaller biocarbon pellets is preferably larger than the average particle diameter of the initial carbon-containing particles used to make the pellets with the binder.

[0168] When the bio-carbon pellets are crushed to produce smaller bio-carbon pellets, the crushing (and optional screening) step can be integrated with step (e), can occur after step (e), can occur after step (f), or can occur after step (f), potentially including at an industrial location. The optional step to produce smaller bio-carbon pellets can utilize a crushing device selected from a hammer mill, attrition mill, disc mill, pin mill, ball mill, cone crusher, jaw crusher, rock crusher, or combinations thereof.

[0169] In various process embodiments, the Hardgrove Grindability Index is at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, or at least 100. For example, the Hardgrove Grindability Index can be from about 30 to about 50, or from about 40 to about 70. Reference can be made to the examples herein, which show a range of HGI values ​​from 30 to 117.

[0170] Some embodiments provide a process for producing bio-carbon pellets, comprising: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a bio-reagent, the bio-reagent containing at least about 50% by weight carbon and at least about 5% by weight moisture; (c) mechanically treating the biological reagent, thereby generating a plurality of carbon-containing particles; (d) combining the carbon-containing particles with a binder to form a carbon-binder mixture; (e) subsequent to or simultaneously with step (d), pelletizing the carbon-binder mixture, thereby producing bio-carbon pellets; (f) optionally, at least partially drying the bio-carbon pellets; The present invention provides a process whereby the biocarbon pellets are characterized by an average Hardgrove Grindability Index that is specifically adjusted via process conditions to range from about 30 to about 120.

[0171] Some embodiments provide a process for producing bio-carbon pellets, comprising: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a bio-reagent, the bio-reagent containing at least about 50% by weight carbon and at least about 5% by weight moisture; (c) mechanically treating the biological reagent, thereby generating a plurality of carbon-containing particles; (d) combining the carbon-containing particles with a binder to form a carbon-binder mixture; (e) subsequent to or simultaneously with step (d), pelletizing the carbon-binder mixture, thereby producing bio-carbon pellets; (f) optionally, at least partially drying the bio-carbon pellets; The present invention provides a process whereby the biocarbon pellets are characterized by an average Hardgrove Grindability Index that is specifically adjusted via process conditions to range from about 40 to about 70.

[0172] In various processes, the process conditions may range from about, at least about, or at most about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 8, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, or 130.

[0173] The process conditions optimized for a typical biocarbon pellet having a particular desired HGI can be the conditions in step (a), step (b), step (c), step (d), step (e), step (f), two such steps, three such steps, four such steps, five such steps, or all six such steps.

[0174] In some embodiments, the process includes preselecting a hardgrove grindability index, adjusting process conditions based on the preselected hardgrove grindability index, and achieving within ±20% of the preselected hardgrove grindability index for the biocarbon pellets, where the adjusted process conditions include adjusting one or more of pyrolysis temperature, pyrolysis time, mechanical treatment conditions, pelletizing conditions, binder type, binder concentration, binding conditions, and drying. The process of certain embodiments can achieve within ±10%, or within ±5%, of the preselected hardgrove grindability index for the biocarbon pellets.

[0175] Some embodiments can be understood with reference to FIG. 1. The dotted boxes and lines indicate optional units and flows, respectively. In the block flow diagram of FIG. 1, a biomass feedstock is pyrolyzed, thereby producing bio-reagents and off-gases. The bio-reagents are conveyed to a mechanical processing unit, producing bio-carbon particles (e.g., powder). The bio-carbon particles are conveyed to a pelletizing unit, which is also provided with a binder, thereby producing bio-carbon pellets. The bio-carbon pellets are optionally dried. The pyrolysis off-gases are optionally combusted, thereby producing heat for process purposes, including (but not limited to) pellet drying operations.

[0176] FIG. 2 is a photograph of bio-carbon pellets produced by the process of FIG. 1 using a softwood / hardwood mix (red pine and maple) as the starting biomass in an exemplary embodiment.

[0177] Another variation of the present invention is a system for producing bio-carbon pellets, comprising: a pyrolysis reactor configured to pyrolyze a biomass feedstock, thereby producing a bio-reagent, the bio-reagent comprising at least about 50% by weight carbon and at least about 5% by weight moisture; a mechanical device configured to mechanically process the biological reagent, thereby generating a plurality of carbon-containing particles; a pelletizing unit configured to pelletize the mixed carbon-containing particles and binder, thereby producing bio-carbon pellets; and optionally a dryer configured to at least partially dry the bio-carbon pellets; The system is capable of producing biocarbon pellets characterized by an adjustable average hardgrove grindability index of at least 30.

[0178] Another variation of the present disclosure is a bio-carbon pellet produced by a process comprising: (a) providing a biomass feedstock; (b) pyrolyzing the biomass feedstock, thereby producing a bio-reagent, the bio-reagent containing at least about 50% by weight carbon and at least about 5% by weight moisture; (c) mechanically treating the biological reagent, thereby generating a plurality of carbon-containing particles; (d) combining the carbon-containing particles with a binder to form a carbon-binder mixture; (e) subsequent to or simultaneously with step (d), pelletizing the carbon-binder mixture, thereby producing bio-carbon pellets; (f) optionally, at least partially drying the bio-carbon pellets; The biocarbon pellets are characterized by an average hardgrove grindability index of at least 30.

[0179] The bio-carbon pellets disclosed herein have a wide variety of downstream applications. They can be stored, sold, shipped, and converted into other products. They can be pulverized for use in boilers to burn carbon and generate electrical energy or heat. They can be pulverized, crushed, or milled for feeding into furnaces, such as blast furnaces in metal production. They can be fed directly into furnaces, such as Tecnored furnaces in metal production. They can be pulverized, crushed, or milled for feeding into gasifiers for the purpose of making syngas from the bio-carbon pellets.

[0180] It should be noted that despite the Hardgrove Crushability Index of biocarbon pellets, they do not necessarily undergo a subsequent grinding process. For example, biocarbon pellets can be used directly in agricultural applications. As another example, biocarbon pellets can be directly incorporated into engineered structures, such as landscape walls. Then, at the end of the life of the structure containing the biocarbon pellets, the pellets can be crushed, burned, gasified, or otherwise reused or regenerated.

[0181] In many embodiments, the biocarbon pellets are fed into a furnace, either directly or after a step of pulverizing, crushing, grinding, or otherwise reducing the particle size. The furnace can be a blast furnace, a top gas recirculating blast furnace, a shaft furnace, a reverberatory furnace (also known as an air furnace), a crucible furnace, a silencer furnace, a retort furnace, a flash furnace, a Tecnored furnace, an Ausmelt furnace, an ISASMELT furnace, a puddle furnace, a bogie 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, a direct reduction metal furnace, or a combination or derivative thereof.

[0182] The biocarbon pellets with adjustable HGI or reactivity moderators can be utilized in metal production processes. An exemplary metal production process is a process configured to produce impure or pure metals selected from iron, copper, nickel, magnesium, manganese, aluminum, tin, zinc, cobalt, chromium, tungsten, molybdenum, silicon, or combinations thereof. The starting 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, silicon oxide, or combinations thereof. The starting metal oxide can be reacted with carbon (contained in the biocarbon pellets) to produce CO or CO2 along with the metal product, preferably in a fully reduced form (e.g., Fe), but which can also be a metal oxide in a less oxidized form (e.g., FeO) compared to the starting metal oxide (e.g., Fe2O3).

[0183] Another example is the production of silicon (Si) from silica (SiO2). Silicon is a metalloid that is considered a metal in this disclosure. Silicon production is typically carried out in an electric arc furnace, in which SiO2 is converted to Si and CO via carbothermal reduction. SiO2+2C→Si+2CO

[0184] In this desired chemical reaction, the carbon in the biocarbon pellets reacts to extract oxygen from the SiO2. This reaction can be enhanced when the particle size is reduced through pellet grinding, as smaller particles improve heat and mass transfer. Thus, HGI is often a critical parameter in silicon production.

[0185] In some embodiments for silicon production, a reactivity moderator (which may be a pellet binder) is selected to change the reactivity of the biocarbon pellets with Si or SiO2. For example, the reactivity moderator can be selected to increase reactivity with SiO2 and produce Si at a faster rate, or the reactivity moderator can be selected to decrease reactivity with SiO2 for reactor control purposes. The reactivity moderator can be selected to decrease reactivity with Si, for example, to inhibit the formation of silicon carbide (SiC), which competes with pure Si production.

[0186] 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.

[0187] "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 less than 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.

[0188] Exemplary changes that may occur during pyrolysis include any of the following: (i) heat transfer from a heat source increases the temperature within the feed; (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 non-pyrolyzed feed; (iv) some of the volatiles in the cooler portions of the feed may condense, followed by secondary reactions to produce tars; (v) autocatalytic secondary pyrolysis reactions proceed while competing primary pyrolysis reactions occur simultaneously; and (vi) further pyrolysis, reforming, water-gas shift reactions, free radical recombination, or dehydration, which are functions of residence time, temperature, and pressure profiles, may also occur.

[0189] Pyrolysis can at least partially dewater the starting material (e.g., lignocellulosic biomass). In various embodiments, pyrolysis removes about 50%, 75%, 90%, 95%, 99% or more of the water from the starting material.

[0190] In some embodiments, the starting 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, sugar beet, sugar beet pulp, sunflower, sorghum, canola, algae, miscanthus, alfalfa, switchgrass, fruit, fruit pulp. The biomass feedstock may be selected from shells, fruit stems, fruit skins, fruit seeds, vegetables, vegetable shells, vegetable stems, vegetable skins, 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, lignin, animal manure, municipal solid waste, municipal sewage, or combinations thereof. It is noted that biomass feedstocks typically contain at least carbon, hydrogen, and oxygen.

[0191] The bioreagent may comprise at least about 50%, at least about 75%, or at least about 90% carbon (total carbon) by weight. In various embodiments, the bioreagent contains about, at least about, or at most about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% carbon by weight. 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.

[0192] The bioreagent can include at least about 50%, at least about 75%, or at least about 90% fixed carbon by weight, hi various embodiments, the bioreagent contains about, at least about, or at most about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% total carbon by weight.

[0193] The carbon (within the bioreagent) can be, for example, at least about 50%, at least about 75%, or at least about 90% by weight fixed carbon, with 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.

[0194] Pyrolysis conditions can vary widely depending on the desired composition of the bioreagent and pyrolysis off-gas, starting materials, reactor configuration, and other factors.

[0195] 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.

[0196] In some non-limiting embodiments, the temperature and residence time are preferably selected to achieve a relatively slow pyrolysis chemical reaction. 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, it is preferable to utilize equipment that does not mechanically disrupt the cell walls or otherwise convert the biomass particles into small fines. Preferred reactor configurations are discussed in accordance with the process description below.

[0197] 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 tends to preserve 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.

[0198] 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.

[0199] In some embodiments, the second zone of the pyrolysis reactor is configured as a primary reaction zone, where the 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 (mainly cellulose, hemicellulose, and lignin) decompose to create vapors that escape by penetrating pores or creating new nanopores. The latter effect contributes to the creation of porosity and surface area.

[0200] In some embodiments, the third zone of the pyrolysis reactor is configured to receive the high carbon reaction intermediates and to cool the solids to some extent. Typically, the third zone is at a lower temperature than the second zone. In the third zone, the chemical reactions and mass transfer can be surprisingly complex. Without being limited by a particular theory or proposed mechanism, it is believed that secondary reactions can occur in the third zone. Essentially, carbon-containing components in the gas phase can decompose to form additional fixed carbon or become adsorbed onto carbon. Thus, in some embodiments, the final carbonaceous material is not simply the solid degassed residue of the processing step, but includes additional carbon deposited from the gas phase, such as by decomposition of organic vapors (e.g., tars) that can form carbon.

[0201] 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.

[0202] 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 adjustments.

[0203] Some embodiments do not use fast pyrolysis, and some embodiments do not use slow pyrolysis.Surprisingly, high quality carbon materials, including compositions having a very high percentage of fixed carbon, can be obtained from the disclosed processes and systems.

[0204] 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 at least a portion of the moisture contained within the feedstock; (c) optionally degassing the feedstock to remove at least a portion of the interstitial oxygen, if any, contained in the feedstock; (d) pyrolyzing the feedstock in the presence of a substantially inert gas phase at at least one 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 at least a portion of the condensable vapors and at least a portion of the non-condensable gases from the high temperature pyrolysis solids; (f) cooling the high temperature pyrolysis solid, thereby producing a cooled pyrolysis solid; (g) recovering a carbon-rich biological reagent comprising at least a portion of the cooled pyrolysis solids.

[0205] "Biomass" for the purposes of this disclosure shall be construed as any living material or mixture of living and non-living materials. Essentially, biomass contains at least carbon, hydrogen, and oxygen. The method and apparatus of the present invention can accommodate a wide range of materials of different types, sizes, and moisture contents.

[0206] Biomass includes, for example, plants and plant-derived materials, vegetation, agricultural waste, forestry waste, wood waste, paper waste, animal waste, poultry waste, and municipal solid waste. In various embodiments of the present invention that utilize 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 fabrics. Those skilled in the art will readily appreciate that the options for feedstock are virtually limitless.

[0207] The present invention 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 biofeedstock is or includes coal, oil shale, crude oil, asphalt, or solids from crude oil processing (such as petroleum coke). Feedstocks can include waste 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 trucks, trains, ships, barges, tractor trailers, or any other vehicle or transportation means.

[0208] The selection of the particular raw material(s) is not considered technically critical, but is done in a manner that tends to favor an economical process. Typically, regardless of the raw material selected, there may (in some embodiments) be screening to remove undesirable materials. The raw material may optionally be dried prior to processing.

[0209] 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 that are pressed together or otherwise bound, such as with a binder.

[0210] 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 invention since 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 invention. Of note, some market applications of high carbon products do require large sizes (e.g., on the order of centimeters), so in some embodiments, large pieces are supplied, produced, and sold.

[0211] 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 the present invention. 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 the product have similar geometric shapes, such as spheres, cylinders, or cubes.

[0212] 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.

[0213] The starting feedstock may be provided with a range of moisture levels, as will be appreciated. In some embodiments, the feedstock may already be sufficiently dry that it does not need to be further dried prior to pyrolysis. Typically, it is desirable to utilize commercial sources of biomass that normally contain moisture, and feed the biomass through a drying step prior to introduction into the pyrolysis reactor. However, in some embodiments, dry feedstock may be utilized.

[0214] 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% O2 in the gas phase. First, uncontrolled combustion should be avoided in the pyrolysis reactor for safety reasons. Some amount of total carbon oxidation to CO2 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, will reduce the carbon yield to solids.

[0215] 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 there is little or no oxygen in the pyrolysis reactor, it may be preferable to remove air from the feed before it is introduced into the reactor. There are various methods to remove or reduce air in the feedstock.

[0216] In some embodiments, before or after drying, a degassing unit is utilized where the feedstock is conveyed in the presence of another gas that can remove adsorbed oxygen and permeate the feedstock pores to remove oxygen from the pores. Essentially any gas with less than 21% O2 by volume can be used with varying effectiveness. In some embodiments, nitrogen is used. In some embodiments, CO or CO2 is used. Mixtures can be used, such as a mixture of nitrogen and small amounts of oxygen. Water vapor may be present in the degassed 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 to an exhaust treatment unit) or recycled.

[0217] 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.

[0218] Various types of degassing units can be used. If drying is performed, it may be inefficient to clean soluble oxygen from the moisture present, so drying and then degassing may be preferred. In certain embodiments, the drying and degassing steps are combined in a single unit, or some amount of degassing is achieved during drying, etc.

[0219] The optionally dried and optionally degassed feedstock is introduced into the 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.

[0220] When a single reactor is used, there are preferably multiple zones, such as two, three, four or more zones, which can allow separate control of temperature, solids residence time, gas residence time, gas composition, flow pattern, or pressure to adjust the overall process performance.

[0221] 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, the boundaries of zones may relate to structures such as the presence of flights within the reactor or separate heating elements to provide heat to separate zones. Alternatively or additionally, the boundaries of zones 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.

[0222] 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 "preheat" may continue to occur in the pyrolysis zone. The temperature profile in the reactor is typically continuous, including at zone boundaries within the reactor.

[0223] 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., such as from about 300° C. to about 400° C. The temperature of the first zone is preferably not so high as to bombard the biomass material and rupture the cell walls and initiate rapid decomposition of the solid phase into vapors and gases.

[0224] All references to zone temperatures herein should be interpreted without limitation to include temperatures that may be applied to the bulk solids present, or the gas phase, or the reactor walls (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 references 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.

[0225] The second zone, or generally the first pyrolysis zone, is operated under pyrolysis or carbonization conditions. The temperature of the second zone can be selected from about 250°C to about 700°C, 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, leaving behind a significant amount of solid material as a high carbon reaction intermediate. The biomass components (mainly cellulose, hemicellulose, and lignin) decompose to create steam, which escapes by permeating through pores or by creating new pores. The preferred temperature depends on at least the residence time of the second zone, as well as the nature of the feedstock and the desired product properties.

[0226] The third zone, or cooling zone, is operated to cool the high carbon reaction intermediates 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.

[0227] 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 reduction 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 Boudoir reaction to convert carbon monoxide to carbon dioxide and fixed carbon.

[0228] 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.

[0229] It should be recognized that in a multiphase reactor, there are multiple residence times. In the present context, there are residence times (and residence time distributions) of both 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 combined on the solid side, but if multiple inlet and outlet ports are utilized in the individual zones, the residence times may not be combined on the vapor side. The residence times of the solids and vapor are not combined.

[0230] 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 time sufficient to allow the biomass to reach the desired preheat temperature is desirable. Heat transfer rates, which depend on particle type and size, physical equipment, and heating parameters, dictate the minimum residence time required to allow the solids to reach the desired preheat temperature. Additional time is undesirable, as it contributes to higher capital costs, unless some amount of mild pyrolysis is intended in the preheat zone.

[0231] 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 enough time for the necessary heat transfer to occur followed by the chemical reaction of carbonization. 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 its production of steam and gases from the carbon itself, which should be avoided if the intended product is solid carbon.

[0232] In a static system, there will be an equilibrium conversion that can be substantially reached at a certain time. When steam is continuously flowing over the solids with continuous devolatilization, as in certain embodiments, the equilibrium constraint can be removed to allow pyrolysis and devolatilization to continue until the reaction rate approaches zero. Longer times will not tend to substantially change the remaining refractory solids.

[0233] 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 enough time to allow the carbon solids to cool to the desired temperature. The cooling rate and temperature dictate the minimum residence time necessary to allow the carbon to cool. Additional time is not desirable unless some amount of secondary pyrolysis is desired.

[0234] As mentioned above, the residence times of the vapor phases can be selected and controlled separately. The vapor residence time of the preheat zone can be selected from about 0.1 minutes to about 15 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. The vapor residence time of the pyrolysis zone can be selected from about 0.1 minutes to about 20 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes. The vapor residence time of the cooling zone can be selected from about 0.1 minutes to about 15 minutes, for example, about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes. A short vapor residence time promotes rapid clearing of volatiles from the system, while a longer vapor residence time promotes reaction of components in the vapor phase with the solid phase.

[0235] 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 with solids and vapor flowing 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 gas phase from the batch vessel.

[0236] 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. Typically, the flow of solids can approach plug flow (well mixed in the radial dimension), while the flow of vapor can approach perfectly mixed flow (high velocity transport in both radial and axial dimensions). Multiple inlet and outlet ports for the vapor can contribute to the overall mixing.

[0237] 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.

[0238] The process can be conveniently operated at atmospheric pressure in some embodiments. Operation at atmospheric pressure has many advantages ranging from mechanical simplicity to improved safety. In certain 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).

[0239] Vacuum operation (e.g., 10-100 kPa) facilitates rapid sweeping of volatiles from the system. Higher pressures (e.g., 100-1000 kPa) may be useful if the off-gas is fed to a high-pressure operation. Higher pressures may also be useful to facilitate heat transfer, chemical reactions, or separations.

[0240] The step of separating at least a portion of the condensable vapors and at least a portion of the 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.

[0241] The sweep gas can be, for example, N2, Ar, CO, CO2, H2, H2O, CH4, other light hydrocarbons, or combinations thereof. The sweep gas can be initially preheated before introduction, or it can be cooled if obtained from a heating source.

[0242] The sweep gas removes volatile components more completely 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 obtained simply from volatilization at a given process temperature. Alternatively, the use of a sweep gas allows a more gentle temperature to be used to remove a particular amount of volatiles. 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 limitations of volatilization as well as the thermodynamic limitations by continuously depleting a given volatile species to allow more volatile species to evaporate and achieve thermodynamic equilibrium.

[0243] 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 the rapid removal of steam can increase porosity in the pyrolyzed solids. Higher porosity is desirable for some products.

[0244] In certain embodiments, the sweep gas, in conjunction with a relatively low process pressure, such as atmospheric pressure, provides rapid vapor removal without requiring large amounts of inert gas.

[0245] In some embodiments, the sweep gas flows countercurrent to the feed flow direction. In other embodiments, the sweep gas flows cocurrent to the feed flow direction. In some embodiments, the flow patterns of the solids approach plug flow, while the flow patterns of the sweep gas and vapor phase generally approach perfectly mixed flow in one or more zones.

[0246] The sweep may be performed in any one or more of the reactor zones. In some embodiments, the sweep gas is introduced into the cooling zone and extracted (along with generated volatiles) from the cooling or pyrolysis zone. In some embodiments, the sweep gas is introduced into the pyrolysis zone and extracted from the pyrolysis or preheating zone. In some embodiments, the sweep gas is introduced into the preheating zone and extracted from the pyrolysis zone. In these or other embodiments, the sweep gas may be introduced into each of the preheating zone, pyrolysis zone, and cooling zone, and may also be extracted from each of the zones.

[0247] In some embodiments, the zone or zones in which the separation is carried out are units physically separated from the reactor. Separation units or zones can be located between reactor zones, if desired. For example, a separation unit can be installed between a pyrolysis unit and a cooling unit.

[0248] The sweep gas can be introduced continuously, especially if the solids flow is continuous. If the pyrolysis reaction is run 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 run continuously, the sweep gas can be introduced semi-continuously or periodically, if desired, with suitable valves and controls.

[0249] The volatiles-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 control of 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.

[0250] 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 an air exhaust if desired. Preferably, the energy content of the thermal oxidizer effluent is 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 (utility side) the dryer. The thermal oxidizer can use fuels other than natural gas.

[0251] The yield of carbonaceous materials may 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 split 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 the process conditions, including the water present.

[0252] 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 contains from about 40% to about 70% of the carbon contained in the starting feedstock. The remaining carbon forms methane, carbon monoxide, carbon dioxide, light hydrocarbons, aromatics, tars, terpenes, alcohols, acids, aldehydes, or ketones to varying degrees.

[0253] In alternative embodiments, some portion of these compounds are combined with carbon-rich solids to enrich 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 originating from a cooling zone or a separate cooling unit. These embodiments are described in more detail below.

[0254] 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 collected and simply cooled at a slow rate. If the carbonaceous solids are reactive or unstable in air, it may be desirable to maintain an inert atmosphere or to rapidly cool the solids, e.g., 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. "Cooling unit" should be broadly construed to include vessels, tanks, pipes, or portions thereof.

[0255] In some embodiments, the process further comprises operating a cooling unit to cool the warm pyrolyzed solids with steam, thereby producing low temperature pyrolyzed solids and superheated steam, and drying is performed at least in part with the superheated steam obtained from the external cooler. Optionally, the cooling unit can be operated to first cool the warm pyrolyzed solids with steam to reach a first cooling unit temperature and then 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 pyrolyzed solids in the presence of air.

[0256] Following cooling to ambient conditions, the carbonaceous solids may be collected and 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.

[0257] Some other means for screening or 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.

[0258] Various additives can be introduced throughout the process before, during, or after any of the steps 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 products containing bioreagent) properties.

[0259] The additives can be added before, during, or after any one or more steps of the process, including adding 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, landing 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 additives. If desired, the additives can be added after carbonization, or even after grinding.

[0260] In some embodiments, the additive is selected from a metal, a metal oxide, a metal hydroxide, or a combination thereof. For example, the additive can be selected from, but is 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, or a combination thereof.

[0261] 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.

[0262] 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 basic metal salts with hydrohalic acids, 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.

[0263] 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 the formation of solids and gases, or in favor of the formation of solids.

[0264] Without being limited to any particular hypothesis, the additives can chemically modify the starting biomass, or the treated biomass prior to pyrolysis, to reduce cell wall fracture for greater strength / integrity. In some embodiments, the additives can increase the fixed carbon content of the biomass feedstock prior to pyrolysis.

[0265] The additives may result in the bioreagent having improved mechanical properties, such as yield strength, compressive strength, tensile strength, fatigue strength, impact strength, elastic modulus, bulk modulus, or shear modulus. The additives may improve mechanical properties by simply being present (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 may occur within a portion of the bioreagent that contains the additive, thereby improving the final strength.

[0266] 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 of a liquid solution (such as in an aqueous solution or solvent) or by immersion in a tank, bin, bag, or other container.

[0267] 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.

[0268] 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.

[0269] Throughput or process capacity can vary widely from small laboratory scale units to full scale operations, including any pilot, demonstration, or semi-commercial scale. In various embodiments, the process capacity (of feedstock, product, or both) is at least about 1 kg / day, 10 kg / day, 100 kg / day, 1 ton / day (all tons are metric tons), 10 tons / day, 100 tons / day, 500 tons / day, 1000 tons / day, 2000 tons / day, or more.

[0270] In some embodiments, a portion of the solids produced may 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 may be higher in fixed carbon. The solids, liquids, and gas streams produced or present in the process may be independently recycled, passed to a subsequent step, or removed / purged from the process at any point.

[0271] 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.

[0272] Some variations of the present disclosure include: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operative communication with the feeding apparatus and configured to remove moisture contained within the carbon-containing feedstock; and (c) a multi-zone reactor disposed in operative communication with the dryer, the multi-zone reactor configured to contain at least one pyrolysis zone disposed in operative communication with a spatially separated cooling zone and having an outlet for removing condensable vapors and non-condensable gases from the solids; (d) a solid-state cooler disposed in operative communication with the multi-zone reactor; and (e) a high carbon biological reagent production system comprising a high carbon biological reagent recovery unit disposed in operative communication with the solid-state cooler.

[0273] Some variations include: (a) a feeder configured to introduce a carbon-containing feedstock; (b) an optional dryer disposed in operative communication with the feeding apparatus and configured to remove moisture contained within the carbon-containing feedstock; and (c) an optional preheater disposed in operative communication with the dryer and configured to heat or gently pyrolyze the feedstock; (d) a pyrolysis reactor disposed in operative communication with the preheater and configured to pyrolyze the feedstock; (e) a cooler disposed in operative communication with the pyrolysis reactor and configured to cool the pyrolysis solids; and (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 at least one gas outlet for removing condensable vapors and non-condensable gases from the solids.

[0274] The feed system can be physically integrated with the multi-zone reactor, such as through the use of a screw feeder or auger mechanism to introduce the feed solids into the first reaction zone.

[0275] 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.

[0276] 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).

[0277] 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.

[0278] The multi-zone reactor is preferably configured with at least a first gas inlet and a first gas outlet, which may be arranged in communication with different zones or the same zone.

[0279] 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.

[0280] 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 yields and efficiency, both dynamically and over time, when operating history can be utilized to adjust process conditions.

[0281] In a preferred embodiment, a reactive gas probe is placed in operative communication with the pyrolysis zone. Such a reactive gas probe can be useful for extracting gases and analyzing them 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, temperature (in one or more zones), pressure (in one or more zones), additives, etc.

[0282] As intended herein, "monitoring and controlling" via a reactive gas probe should be interpreted to include any one or more samplings via the reactive gas probe, and optionally, making process or equipment adjustments based on the measurements, if deemed necessary or desirable, using well-known principles of process control (e.g., feedback, feedforward, proportional-integral-derivative logic, etc.).

[0283] 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. Typically, the reaction gas probe is associated with one gas output or a portion thereof (e.g., a line branched off from the gas output line).

[0284] 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 ("sample sweep"). Such configurations 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) may be different from the process inert gas, if desired, either for reasons of analytical accuracy or to introduce an analytical tracer.

[0285] 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 (gas chromatography, GC; mass spectrometry, MS; GC-MS, or Fourier transform infrared spectroscopy, FTIR, etc.). The CO or CO2 concentration in the gas phase can be measured and used as an indicator of pyrolysis selectivity, for example, to gas / vapor. The terpene concentration in the gas phase can be measured and used as an indicator of pyrolysis selectivity, for example, to liquid.

[0286] 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 pre-heating zone (if present).

[0287] A gas probe for the cooling zone may 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 may also be useful as an independent measurement of temperature (e.g., in addition to a thermocouple located in the cooling zone). This independent measurement may be a correlation between cooling temperature and a measured amount of a particular species. The correlation may be developed separately or may be established after a period of process operation.

[0288] A gas probe for the drying zone can be useful to determine the degree of drying, for example by measuring the moisture content. A gas probe in the preheat zone can be useful, for example, to determine the extent of any mild pyrolysis that occurs.

[0289] 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 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 to the solid phase. Alternatively or additionally, the drying zone can be configured with a gas outlet to generate a substantially countercurrent flow.

[0290] The pyrolysis reactor or reactors can be selected from any suitable reactor configuration capable of carrying out a pyrolysis process. Exemplary reactor configurations include, but are not limited to, fixed bed reactors, fluidized bed reactors, entrained bed reactors, augers, ablation reactors, rotating cones, rotating drum kilns, calciners, roasters, moving bed reactors, transport bed reactors, ablation reactors, rotating cones, or microwave-assisted pyrolysis reactors.

[0291] 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.

[0292] 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 formed 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.

[0293] 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, typically a recycled product gas. References herein to "sand" also include similar substantially inert materials such as glass particles, recovered ash particles, etc. The high rate of heat transfer from the fluidized sand may result in rapid heating of the feedstock. There may be some ablation due to friction with the sand particles. Heat is typically provided by heat exchanger tubes through which the hot combustion gases flow.

[0294] A circulating fluidized bed reactor can be used where 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.

[0295] In some embodiments, the multi-zone reactor is a continuous reactor comprising a feed inlet, a plurality of spatially separated reaction zones configured to separately control 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.

[0296] 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 a separately adjustable heating means independently selected from electrical heat transfer, steam heat transfer, hot oil heat transfer, phase change heat transfer, waste heat transfer, or combinations thereof. In some embodiments, at least one reactor zone is heated with an effluent stream from a thermal oxidizer, if present.

[0297] 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.

[0298] 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.

[0299] In some embodiments, the feedstock inlet comprises a screw or auger feed mechanism. In some embodiments, the carbonaceous solids outlet comprises a screw or auger output mechanism.

[0300] Certain embodiments utilize a rotary calciner 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 the solids flow patterns, as well as heat and mass transport. 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 separately adjustable in each of the reaction zones.

[0301] Other means of agitating the solids can be used, such as an auger, screw, or paddle conveyor. In some embodiments, the reactor includes a single continuous auger positioned throughout each of the reaction zones. In other embodiments, the reactor includes twin screws positioned throughout each of the reaction zones.

[0302] Some systems are specifically designed with the ability to maintain the approximate size of the feedstock throughout the process, i.e., 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.

[0303] In some embodiments of the invention, 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 is preferably configured to receive separate fuel (such as natural gas) and oxidant (such as air) into a combustion chamber adapted to combust at least a portion of the fuel and condensable vapors. Certain non-condensable gases, such as CO or CH4, may also be oxidized to CO2.

[0304] 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 at least a portion of the heat of combustion for the dryer. This embodiment can contribute significantly to the overall energy efficiency of the process.

[0305] 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 vapors in at least partially condensed form with the solids, The carbon enrichment unit can increase the carbon content of the high carbon biological reagent obtained from the recovery unit.

[0306] The system may further include a separate pyrolysis unit adapted to further pyrolyze the high carbon bio-reagent to further increase its carbon content. The separate pyrolysis unit may be a relatively simple container, unit, or device, such as a tank, barrel, bin, drum, tote, sack, or roll-off.

[0307] 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.

[0308] Several variations regarding carbon enrichment of solids are now further described. In some embodiments, the process for producing high carbon bio-reagents includes: (a) providing a carbon-containing feedstock comprising biomass; (b) optionally drying the feedstock to remove at least a portion of the moisture contained within the feedstock; (c) optionally degassing the feedstock to remove at least a portion of the 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 at least a portion of the condensable vapors and at least a portion of the 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; and (h) thereafter, passing at least a portion of the condensable vapors or at least a portion of the non-condensable gases from step (e) through a warm or cold pyrolytic solid to form an enhanced pyrolytic solid having an increased carbon content; (i) recovering a high carbon biological reagent comprising at least a portion of the enhanced pyrolysis solids.

[0309] In some embodiments, step (h) comprises passing at least a portion of the condensable vapors from step (e), in vapor or condensed form, through the warm pyrolytic solids to produce enhanced pyrolytic solids having an increased carbon content. In some embodiments, step (h) comprises passing at least a portion of the non-condensable gases from step (e) through the warm pyrolytic solids to produce enhanced pyrolytic solids having an increased carbon content.

[0310] Alternatively or additionally, the vapor or gas may be contacted with a cold pyrolytic solid. In some embodiments, step (h) comprises passing at least a portion of the condensable vapor from step (e), in vapor or condensed form, through a low temperature pyrolytic solid to produce an enhanced pyrolytic solid having an increased carbon content. In some embodiments, step (h) comprises passing at least a portion of the non-condensable gas from step (e) through a cold pyrolytic solid to produce an enhanced pyrolytic solid having an increased carbon content.

[0311] In certain embodiments, step (h) comprises passing substantially all of the condensable vapors from step (e), in vapor or condensed form, through a low temperature pyrolytic solid to produce an enhanced pyrolytic solid having an increased carbon content. In certain embodiments, step (h) comprises passing substantially all of the non-condensable gases from step (e) through a cold pyrolytic solid to produce an enhanced pyrolytic solid having an increased carbon content.

[0312] 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 consisting of at least a portion of the condensable steam and at least a portion of the non-condensable gas obtained from step (e) can be fed to a separation unit configured to produce at least a first and a second output stream. In certain embodiments, the intermediate feed stream includes all of the condensable steam, all of the non-condensable gas, or both.

[0313] Separation techniques may include or use distillation columns, flash vessels, centrifuges, cyclones, membranes, filters, packed beds, capillary columns, etc. Separation may be primarily based on, for example, distillation, absorption, adsorption, or diffusion and may exploit differences in vapor pressure, activity, molecular weight, density, viscosity, polarity, chemical functionality, affinity to a stationary phase, and any combination thereof.

[0314] 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.

[0315] Thus, in some embodiments, the first output stream includes condensable vapors and the second output stream includes non-condensable gases. The condensable vapors can include at least one carbon-containing compound selected from terpenes, alcohols, acids, aldehydes, or ketones. The vapors from pyrolysis can include aromatic compounds such as benzene, toluene, ethylbenzene, and xylenes. Heavier aromatic compounds such as refractory tars can be present in the vapors. The non-condensable gases can include at least one carbon-containing molecule selected from carbon monoxide, carbon dioxide, or methane.

[0316] 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.

[0317] 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 at least one carbon-containing molecule selected from methanol, furfural, or acetic acid. The non-polar compounds can comprise at least one carbon-containing molecule selected from carbon monoxide, carbon dioxide, methane, terpene, or terpene derivatives.

[0318] Step (h) can increase the total carbon content of the high carbon bio-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.

[0319] In some embodiments, step (h) increases the fixed carbon content of the high carbon bio-reagent. In these or other embodiments, step (h) increases the volatile carbon content of the high carbon bio-reagent. The volatile carbon content is carbon that is attributable to volatile materials in the reagent. The 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 typically remains bound or adsorbed to solids at ambient conditions, but is released upon heating before the fixed carbon is oxidized, gasified, or otherwise released as vapor.

[0320] Depending on the conditions associated with step (h), it is possible for some amount of the volatile carbon to become fixed carbon (e.g., via Boudoir carbon formation from CO). Typically, volatiles enter the pores 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] Condensable vapors can be used for either energy in the process (such as by thermal oxidation) or 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. Any combination of the foregoing is also possible.

[0325] A potential advantage of including step (h) is that the gas stream is scrubbed and the resulting gas stream is enriched in CO and CO2. 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 / CO2 stream is prepared for use as an inert gas, for example, in a reactor system or a cooling system.

[0326] 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.

[0327] 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 solids stream under suitable conditions to form a carbon-containing product having an increased carbon content relative to the carbon-containing material.

[0328] In some embodiments, the starting carbon-containing material is a pyrolyzed or torrefied biomass. The gas stream can be obtained during an integrated process to provide the carbon-containing material. Or, 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.

[0329] 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.

[0330] 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 including 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.

[0331] 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.

[0332] 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.

[0333] 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 operative communication with the feeding apparatus and configured to remove moisture contained within the carbon-containing feedstock; and (c) a multi-zone reactor disposed in operative communication with the dryer, the multi-zone reactor configured to contain at least one pyrolysis zone disposed in operative communication with a spatially separated cooling zone and having an outlet for removing condensable vapors and non-condensable gases from the solids; (d) a solid-state cooler disposed in operative communication with the multi-zone reactor; and (e) a material enrichment unit disposed in operative 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 operative communication with the material concentrating unit.

[0334] The system may further comprise a preheat zone disposed in operative 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 within separate units. Also, a solids cooler may be disposed within the multi-zone reactor.

[0335] In some embodiments, the cooling zone is configured with a gas inlet and the pyrolysis zone is configured with a gas outlet, thereby producing a substantially countercurrent flow of the gas phase to the solid phase. In these or other embodiments, the preheating zone or drying zone (or dryer) is configured with a gas outlet, thereby producing a substantially countercurrent flow of the gas phase to the solid phase.

[0336] In certain embodiments, the system incorporates an ingredient enrichment unit, the ingredient enrichment unit comprising: (i) a housing having an upper portion and a lower portion; (ii) an inlet at a 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; and (iv) a passageway defined between the upper and lower portions of the housing; and (v) a transport system following the pathway, the transport system configured to transport the solid, the housing being shaped such that the solid adsorbs at least a portion of the condensable vapor or at least a portion of the non-condensable gas.

[0337] The present invention can produce a variety of compositions useful as high carbon bio-reagents, and products incorporating such reagents. In some variations, the high carbon bio-reagents 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 at least a portion of the moisture contained within the feedstock; (c) optionally degassing the feedstock to remove at least a portion of the 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 at least a portion of the condensable vapors and at least a portion of the 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 a high carbon bio-reagent comprising at least a portion of the cold pyrolysis solids.

[0338] 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 matter. In some embodiments, carbon from volatile matter 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.

[0339] The high carbon bio-reagent may include about 10% or less, e.g., about 5% or less, hydrogen by weight on a dry basis. The bio-reagent may include about 1% or less, e.g., about 0.5% or less, nitrogen by weight on a dry basis. The bio-reagent may include about 0.5% or less, e.g., about 0.2% or less, phosphorus by weight on a dry basis. The bio-reagent may include about 0.2% or less, e.g., about 0.1% or less, sulfur by weight on a dry basis.

[0340] 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.

[0341] Certain embodiments provide reagents that contain little or essentially no hydrogen (except for any moisture that may be present), nitrogen, phosphorus, or sulfur, and are essentially carbon plus any ash and moisture present. Thus, some embodiments provide bioreagents that have 100% or less carbon on a dry / ash-free (DAF) basis.

[0342] 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 not be a substantial amount of ash in the pyrolysis solids. Ash can be measured, for example, using ASTM D3174.

[0343] Varying amounts of non-combustible materials, such as ash, may be present. The high carbon bio-reagent may include about 10% or less, 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.

[0344] Various amounts of moisture may be present. On a total mass basis, 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 at least on the local environment, such as relative humidity. Moisture may also vary during shipping, preparation for use, and other logistics. Moisture may be measured, for example, using ASTM D3173.

[0345] High carbon bioreagents can have a variety of energy contents, which for the present purposes means an 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.

[0346] The high carbon bio-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.

[0347] In some embodiments, the high carbon bio-reagent is formed into structures comprising compressed, bonded, or aggregated particles. The starting material for forming these bodies may be a powder form of the reagent, such as an intermediate obtained by particle size reduction. The bodies may be formed by mechanical pressing or other forces, optionally with the use of binders or other means of agglomerating the particles together.

[0348] In some embodiments, the high carbon bio-reagent is produced in the form of a structure whose structure is substantially derived from the feedstock. For example, a feedstock chip can produce a product chip of high carbon bio-reagent. Or, a feedstock 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.

[0349] High carbon bioreagents according to the present invention may 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 may be a length, width, or diameter.

[0350] Other variations of the invention relate to the incorporation of additives into the process, into the product, or both. In some embodiments, the high carbon biological reagent includes at least one process additive that is incorporated during the process. In these or other embodiments, the reagent includes at least one product additive that is introduced into the reagent after the process.

[0351] 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% by weight 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.

[0352] 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, or combinations thereof.

[0353] 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% by weight 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.

[0354] 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.

[0355] 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% by weight 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.

[0356] 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.

[0357] Certain high carbon bio-reagents consist essentially of, on a dry basis, carbon, hydrogen, nitrogen, phosphorus, sulfur, non-combustible materials, and additives 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.

[0358] Certain high carbon biological reagents consist essentially of, on a dry basis, 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.

[0359] 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 additives, 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. Further, in various embodiments, the high carbon bioreagent 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.

[0360] 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 enhance final properties for particular applications.

[0361] In preferred 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 certain 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.

[0362] 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.

[0363] The high carbon bioreagents produced as described herein are useful for a wide variety of carbonaceous products. The high carbon bioreagents 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.

[0364] In variations, the product comprises any of the high carbon bioreagents obtainable by the disclosed processes or described in the compositions set forth herein, or any portion, combination, or derivative thereof.

[0365] Generally speaking, the high carbon bioreagents 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 in metal refining (such as reduction of metal oxides) or other industrial processes; or utilized for their material properties in carbon steels and various other metal alloys. Essentially, the high carbon bioreagents can be utilized in any market application of carbon-based commodities or advanced materials, including specialized applications that are developed.

[0366] Prior to suitability or actual use in any product application, the disclosed high carbon bio-reagents 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.

[0367] Products or materials into which these high carbon bio-reagents may 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, fine carbon-based products, stoker carbon-based products, carbon electrodes, or activated carbon products.

[0368] Use of the disclosed high carbon bio-reagents in metal production can reduce slag, increase overall efficiency, and reduce life cycle environmental impacts. Thus, embodiments of the present invention are particularly well suited for metals processing and production.

[0369] Some variations of the present invention 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 the oxygen from the ore, leaving behind the elemental metal.

[0370] The reducing agent may consist of or include a high-carbon bioreagent. In a blast furnace, the high-carbon bioreagent, ore, and typically limestone, may be continuously fed through the top of the furnace, while air (optionally with oxygen enrichment) is blown into the bottom of the chamber, so that chemical reactions occur throughout the furnace as the material moves downward. The end products are usually molten metal and slag phases removed from the bottom, and flue gases exiting the top of the furnace. The downward flow of the ore in contact with the upward flow of hot carbon monoxide-enriched gas is a countercurrent process.

[0371] 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 reactions with CO2, H2O, or O2 and attrition of carbon particles against each other and against other components of the charge. Decomposed carbon particles can cause clogging and reduced performance.

[0372] Coke reactivity test is a highly regarded measure of the performance of carbon in a blast furnace. This test has two components: Coke Reactivity Index (CRI) and Reacted Coke Strength (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.

[0373] In some embodiments, the high carbon bio-reagent provides a carbon product with properties suitable for direct introduction into a blast furnace.

[0374] 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 having a suitable reactivity 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.

[0375] Some embodiments employ one or more additives 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 one or more additives are present in an amount sufficient to provide a high carbon bio-reagent with a CRI of about 40%, 30%, or 20% or less.

[0376] In some embodiments, one or more additives selected from alkaline earth metals, or their oxides or carbonates, are 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 additives. 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).

[0377] In some embodiments, the blast furnace replacement product is a high carbon bioreagent according to the present invention, comprising at least about 55% carbon by weight, about 0.5% or less sulfur, about 8% or less non-combustible materials, and a heating value of at least about 11,000 Btu / lb. In some embodiments, the blast furnace replacement product further comprises about 0.035% or less phosphorus, about 0.5% to about 50% volatile materials by weight, and optionally one or more additives. In some embodiments, the blast furnace replacement product comprises about 2% to about 15% dolomite, about 2% to about 15% dolomitic lime, about 2% to about 15% bentonite, or about 2% to about 15% calcium oxide by weight. In some embodiments, the blast furnace replacement product has a size substantially in the range of about 1 cm to about 10 cm.

[0378] In some embodiments, the high carbon bioreagent according to the present invention is useful as a foundry coke replacement product. Foundry coke is generally characterized as having a carbon content of at least about 85% by weight, a sulfur content of about 0.6% by weight, no more than about 1.5% by weight volatile matter, no more than about 13% by weight ash, no more than about 8% by weight moisture, no more than about 0.035% by weight phosphorus, a CRI value of about 30, and dimensions ranging from about 5 cm to about 25 cm.

[0379] Some variations of the invention utilize high carbon bioreagents as carbon-based taconite pellet addition products. The ores used in making iron and steel are iron oxides. The primary iron oxide ores include hematite, limonite (also called 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 typically require at least 50% iron-containing ore by weight for efficient operation. Iron ore can undergo beneficiation, including crushing, screening, tumbling, flotation, and magnetic separation. The refined ore is often concentrated to over 60% iron and formed into pellets before transportation.

[0380] For example, taconite can be ground 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.

[0381] 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 bio-reagent is introduced into the blast furnace. In these or other embodiments, the high-carbon bio-reagent is incorporated into the taconite pellets themselves. For example, beneficiated taconite ore powder can be mixed with the high-carbon bio-reagent and 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.

[0382] Some variations of the present invention utilize high carbon bio-reagents 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 the conversion of cast iron to ductile iron by the addition of various elements to the ladle.

[0383] The high carbon bio-reagent can be introduced into any type of ladle, but typically the carbon is 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 to the final composition. In some embodiments, the high carbon bio-reagent according to the present invention, when used as a ladle-added 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.

[0384] In some embodiments, the high carbon bio-reagents according to the present invention are useful as ladle added carbon additives, 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).

[0385] 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.

[0386] Direct reduced iron (DRI), also called sponge iron, is produced from the direct reduction of iron ore (in lump, pellet, or fine form) with reducing gases traditionally produced from natural gas or coal. The reducing gas is typically synthesis gas, a mixture of hydrogen and carbon monoxide, which act as reducing agents. 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.

[0387] Iron nuggets are a high quality steelmaking and iron casting feedstock. Iron nuggets are essentially all iron and carbon with little gangue (slag) and low levels of metallic residuals. They are a premium grade pig iron product with excellent transport and handling properties. The carbon contained in the iron nuggets or any portion thereof can be a high carbon bioreagent provided herein. Iron nuggets can be produced by reducing iron ore in a rotary hearth furnace using a high carbon bioreagent as a reducing agent and energy source.

[0388] Some variations of the present invention utilize high carbon bioreagents as metallurgical coke carbon-based products. Metallurgical coke, also known as "meth" coke, is a carbonaceous material typically produced by destructive distillation of various blends of bituminous coals. The final solid is unmelted carbon, called 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. Typical purities range from 86-92% fixed carbon by weight.

[0389] Metallurgical coke is used wherever high quality, tough, 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 treating agents, ceramic packing media, electrolytic processes, and oxygen scavenging.

[0390] Metcoke can be characterized as having a heating value of about 10,000-14,000 Btu / lb and an ash content of about 10% or more by weight. Thus, in some embodiments, the metcoke replacement product comprises a high carbon bioreagent according to the present invention comprising at least about 80%, 85%, or 90% by weight carbon, about 0.8% or less by weight sulfur, about 3% or less by weight volatiles, about 15% or less by weight ash, about 13% or less by weight moisture, and about 0.035% or less by weight phosphorus. The high carbon bioreagent according to the present invention, when used as a metcoke replacement product, can have a size range of, for example, about 2 cm to about 15 cm.

[0391] 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, or combinations thereof.

[0392] Some variations of the invention utilize high-carbon bio-reagents as coal replacement products. Any process or system that uses coal can in principle be adapted to use high-carbon bio-reagents.

[0393] 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 has lower emissions when combusted than the pure coal-based product.

[0394] For example, low rank coal, such as sub-bituminous coal, can be used in applications that would normally require a high rank coal product, such as bituminous coal, by combining a selected amount of a high carbon bio-reagent according to the present invention 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, heating value, etc.), and the desired rank of the final combined product.

[0395] For example, anthracite coal is generally characterized as having at least about 80% carbon by weight, about 0.6% sulfur by weight, about 5% volatile matter by weight, up to about 15% ash by weight, up to about 10% moisture by weight, and a heating value of about 12,494 Btu / lb. In some embodiments, the anthracite coal substitute product is a high carbon bioreagent that includes at least about 80% carbon by weight, up to about 0.6% sulfur by weight, up to about 15% ash by weight, and a heating value of at least about 12,000 Btu / lb.

[0396] In some embodiments, the high carbon bioreagent is useful as a thermal coal replacement product. Thermal coal products are generally characterized as having 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 that includes about 0.5% by weight or less sulfur, about 4% by weight or less ash, and a heating value of at least about 12,000 Btu / lb.

[0397] Some variations of the present invention utilize the high carbon bio-reagent as a carbon-based coking product. Any coking process or system can be adapted to use the high carbon bio-reagent to produce coke or use it as a coke feedstock.

[0398] 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 be comprised of a high carbon bioreagent comprising at least about 50% by weight carbon, about 8% by weight or less ash, about 0.5% by weight or less sulfur, and a heating value of at least about 11,000 Btu / lb. In other embodiments, the thermal coke substitute product further comprises about 0.5% by weight to about 50% by weight volatile matter. The thermal coal or coke substitute product can comprise about 0.4% by weight to about 15% by weight moisture.

[0399] In some embodiments, the high carbon bio-reagent is useful as a petroleum (pet) coke or calcined pet coke replacement product. Calcined pet coke is generally characterized as having at least about 66% carbon by weight, up to about 4.6% sulfur by weight, up to about 5.5% volatiles by weight, up to about 19.5% ash by weight, and up to about 2% moisture by weight, and is typically about 3 mesh or less in size. In some embodiments, the calcined pet coke replacement product is a high carbon bio-reagent that contains at least about 66% carbon by weight, up to about 4.6% sulfur by weight, up to about 19.5% ash by weight, and up to about 2% moisture by weight, and is about 3 mesh or less in size.

[0400] In some embodiments, the high carbon bio-reagent is useful as a coking carbon replacement carbon (e.g., co-calcined with metallurgical coal in a coking furnace). In one embodiment, the coking carbon replacement product is a high carbon bio-reagent that includes at least about 55% by weight carbon, not more than about 0.5% by weight sulfur, not more than about 8% by weight non-combustible materials, and a heating value of at least about 11,000 Btu / lb. In some embodiments, the coking carbon replacement product includes about 0.5% to about 50% by weight volatile materials or one or more additives.

[0401] Some variations of the invention utilize a high carbon bio-reagent as a carbon breeze product, which typically has a very fine particle size, such as 6 mm, 3 mm, 2 mm, 1 mm, or less. In some embodiments, the high carbon bio-reagent according to the invention is useful as a coke breeze replacement product. Coke breeze is generally characterized as having a maximum dimension of about 6 mm or less, a carbon content of at least about 80% by weight, 0.6-0.8% by weight sulfur, 1%-20% by weight volatile matter, up to about 13% by weight ash, and up to about 13% by weight moisture. In some embodiments, the coke breeze replacement product is a high carbon bio-reagent according to the invention comprising at least about 80% by weight carbon, up to about 0.8% by weight sulfur, up to about 20% by weight volatile matter, up to about 13% by weight ash, up to about 13% by weight moisture, and a maximum dimension of about 6 mm.

[0402] In some embodiments, the high carbon bio-reagents are useful as carbon breeze replacement products, for example, during taconite pellet production or in the steelmaking process.

[0403] Some variations utilize high carbon bioreagents as feedstock 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 applications including the production of energy (e.g., combined heat and power) or liquid fuels (e.g., methanol or Fischer-Tropsch diesel fuel).

[0404] In some embodiments, high carbon bio-reagents according to the present invention are useful, for example, as fluidized bed coal replacement products in fluidized bed furnaces where coal is used (eg, for process heat or energy generation).

[0405] Some variations utilize 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, which contribute to the degradation of metal products and cause air pollution. In some embodiments, the carbon furnace addition substitute product with high carbon bioreagent contains about 0.5% or less by weight sulfur, about 4% or less by weight ash, about 0.03% or less by weight phosphorus, and a maximum dimension of about 7.5 cm. In some embodiments, the carbon furnace addition substitute product contains about 0.5% to about 50% by weight volatiles and about 0.4% to about 15% by weight moisture.

[0406] 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 of the impurities.

[0407] In some embodiments, the furnace-added carbon additive is a high-carbon bioreagent comprising at least about 80% by weight carbon, no more than about 0.5% by weight sulfur, no more than about 8% by weight non-combustible material, and a heating value of at least about 11,000 Btu / lb. In some embodiments, the furnace-added carbon additive further comprises up to about 5% by weight manganese, up to about 5% by weight fluorospar, 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.

[0408] Some variations utilize high carbon bio-reagent as a stoker furnace carbon-based product. In some embodiments, the high carbon bio-reagent according to the present invention 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).

[0409] Some variations utilize a high carbon bio-reagent as an injectable (e.g., fine) carbon-based material. In some embodiments, the high carbon bio-reagent 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% carbon by weight, about 0.55 to about 3% sulfur by weight, up to about 5.5% volatiles by weight, up to about 10% ash by weight, up to about 2% moisture by weight, and is about 6 mesh or less in size. In some embodiments, the calcined pet coke replacement product is a high carbon bio-reagent that includes at least about 66% carbon by weight, up to about 3% sulfur by weight, up to about 10% ash by weight, up to about 2% moisture by weight, and is about 6 mesh or less in size.

[0410] 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.

[0411] In some embodiments, the high carbon bio-reagent is useful, for example, as a pulverized carbon replacement product whenever pulverized coal is used (e.g., for process heat or energy generation). In some embodiments, the pulverized coal replacement product comprises up to about 10 percent calcium oxide.

[0412] Some variations utilize high carbon bioreagent as a carbon addition product for metal production. In some embodiments, the high carbon bioreagent according to the present invention is useful as a carbon addition product 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 reduce metal quality and contribute to air pollution. In some embodiments of the present invention, the carbon addition product comprises about 0.5% by weight or less sulfur, about 4% by weight or less ash, about 0.03% by weight or less phosphorus, a minimum dimension of about 1-5 mm, and a maximum dimension of about 8-12 mm.

[0413] Some variations utilize high carbon bio-reagents in 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.

[0414] Other applications of high carbon bio-reagents in carbon electrodes include applications in 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.

[0415] Some variations of the present invention utilize high carbon bioreagents as catalyst supports. Carbon is a known catalyst support in a wide range of catalytic chemical reactions, such as mixed alcohol synthesis 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.

[0416] 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. In various embodiments, the high carbon bioreagents provided herein can provide superior activated carbon products due to (i) greater surface area than fossil fuel-based activated carbons; (ii) carbon renewability; (iii) the vascularity of the biomass feedstock in combination with additives allows better penetration / distribution of additives to enhance pollutant control; and (iv) less inert material (ash) resulting in greater reactivity.

[0417] 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.

[0418] 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 bio-reagent used as a carbon electrode or activated carbon can be introduced into a combustion process for energy value or into a metal fabrication (e.g., reduction of metal ores) process, etc., at the end of its useful life as a performance material.

[0419] Some embodiments may use the bio-reagent due to its reactivity / sorption properties and also as a fuel. For example, a bio-reagent injected into the 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.

[0420] Compared to conventional fossil fuel-based products, high carbon bio-reagents can entail significant environmental and product use advantages: They can be not only environmentally superior, but also functionally superior from a processing standpoint, for example, due to higher purity.

[0421] For some embodiments of metal production, production of bio-reagents by the disclosed process reduces CO, CO2, NO, and CO2 emissions compared to the coking of coal-based products required to prepare them for use in metal production. x , which can result in significantly lower emissions of SO2 and harmful air pollutants.

[0422] The use of high carbon bioreagents instead of coal or coke also significantly reduces environmental emissions of SO2, hazardous air pollutants, and mercury.

[0423] 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.

[0424] In some embodiments, the bio-reagent functions as activated carbon. In certain embodiments, a portion of the bio-reagent is recovered as an activated carbon product, and another portion of the bio-reagent (e.g., the remaining portion) is pelletized using a binder to produce bio-carbon pellets. In other embodiments, the bio-reagent is pelletized using a binder to produce bio-carbon pellets, which are shipped for later conversion to the activated carbon product. Later conversion can include pulverization back to a powder, and can also include chemical treatment, for example, with steam, acid, or base. In these embodiments, the bio-carbon pellets can be considered activated carbon precursor pellets.

[0425] In certain embodiments, the fixed carbon in the bio-reagent can be used primarily to make activated carbon and the volatile carbon in the bio-reagent can be used primarily to make reducing gas. For example, at least 50% by weight, at least 90% by weight, 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% by weight, at least 90% by weight, or essentially all of the volatile carbon in the bio-reagent produced in step (b) can be directed to reducing gas (e.g., via a steam reforming reaction of the volatile carbon to CO).

[0426] The activated carbon, when produced, can be characterized, for example, by an iodine value of at least about 500, 750, 800, 1000, 1500, or 2000. The activated carbon is preferably 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. In some embodiments, 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 C isotope ratio measurements.

[0427] In some embodiments, the pyrolysis reactor is configured to optimize the production of different types of activated carbon. For example, reaction conditions (e.g., time, temperature, and water vapor concentration) can be selected for an activated carbon product with a particular attribute, 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 pyrolysis reactor can operate in a campaign mode to produce one product and then switch to another mode for another product. The first product may be continuously or periodically removed during the first campaign, or may be removed before switching the reaction conditions of the pyrolysis reactor.

[0428] The activated carbon can be characterized, for example, by an iodine value of at least about 500, 750, 1000, 1500, or 2000. The activated carbon is preferably 14 C / 12 In some embodiments, the activated carbon is characterized by a renewable carbon content of at least 90% as determined from C isotope ratio measurements. 14 C / 12 It is characterized as a (fully) renewable activated carbon, as determined from C isotope ratio measurements.

[0429] The activated carbon produced by the processes disclosed herein can be used in a number of ways.

[0430] 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 the local feedstock.

[0431] Activated carbon prepared according to the processes disclosed herein can have the same or better properties than conventional fossil fuel-based activated carbon. In some embodiments, the activated carbon has a surface area comparable to, equal to, or greater than that associated with fossil fuel-based activated carbon. In some embodiments, the activated carbon can control contaminants similar to or better than conventional activated carbon products. In some embodiments, the activated carbon has an inert material (e.g., ash) level 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 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, substantially similar, or the same as pore sizes associated with conventional activated carbon products. In some embodiments, the activated carbon has particle abrasion resistance values ​​comparable, substantially similar, or the same as particle abrasion resistance values ​​associated with conventional activated carbon products. In some embodiments, the activated carbon has hardness values ​​comparable, substantially similar, or the same as hardness values ​​associated with conventional activated carbon products. In some embodiments, the activated carbon has bulk density values ​​comparable, substantially similar, or the same as bulk density values ​​associated with conventional activated carbon products. In some embodiments, the activated carbon products have adsorption capacities comparable, substantially similar, or the same as adsorption capacities associated with conventional activated carbon products.

[0432] 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 properties of potential importance include density, particle size, surface area, microporosity, absorbency, adsorption, binding capacity, reactivity, desulfurization activity, basicity, hardness, and iodine number.

[0433] 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.

[0434] The bulk density for biogenic activated carbon can be, for example, from about 50 g / liter to about 650 g / liter.

[0435] The surface area of ​​biogenic activated carbon can vary widely. An exemplary surface area (e.g., BET surface area) is about 400 m 2 / g~about 2000m 2 / g or more, e.g., 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.

[0436] 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.

[0437] 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 the micropore (e.g., 0-20 Å) content. It is an important measurement for liquid phase applications. Exemplary iodine numbers for activated carbon products produced by embodiments of the present disclosure include about 500, 600, 750, 900, 1000, 1100, 1200, 1300, 1500, 1600, 1750, 1900, 2000, 2100, and 2200, including all intervening ranges. The units of iodine number are milligrams of iodine per gram of carbon.

[0438] Another pore-related measurement is the Methylene Blue Number, which measures mesopore content (e.g., from 20 to 500 Å). Exemplary Methylene Blue Numbers for activated carbon products produced by embodiments of the present disclosure include about 100, 150, 200, 250, 300, 350, 400, 450, and 500, including all intervening ranges. The units of Methylene Blue Number are milligrams of methylene blue (methylthioninium chloride) per gram of carbon.

[0439] Another pore-related measurement is the Molasses Number, which measures macropore content (e.g., >500 Å). Exemplary Molasses Numbers for activated carbon products produced by embodiments of the present disclosure include 100, 150, 200, 250, 300, 350, and 400, including all intervening ranges. The units of Molasses Number are milligrams of molasses per gram of carbon.

[0440] In some embodiments, the activated carbon is at least about 0.5 cm 3 / g, e.g., at least about 1 cm 3 It is characterized by its mesopore volume in g / g.

[0441] 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%.

[0442] Hardness or wear number is a measure of the wear resistance of activated carbon. It is an indication of the physical integrity of activated carbon to withstand frictional forces and mechanical stresses during handling or use. While some hardness is desirable, too much hardness can cause excessive equipment wear. Exemplary wear numbers measured according to ASTM D3802 range from about 1% to greater than about 99%, for example, 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 greater than about 99%.

[0443] In some embodiments, an optimum range of hardness can be achieved where the activated carbon is reasonably abrasive 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 applications can handle high hardness, the process of the present disclosure can operate to increase or maximize hardness to produce a biogenic activated carbon product having an abrasion 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%.

[0444] The biogenic activated carbon provided by the present disclosure has a wide range of commercial applications. For example, but not limited to, the biogenic activated carbon can be utilized in emission control, water purification, ground water 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.

[0445] In one embodiment, a method of using activated carbon to reduce emissions includes: (a) providing activated carbon particles comprising a biogenic activated carbon composition recovered from a second reactor as disclosed herein; (b) providing a gas phase exhaust stream containing at least one selected contaminant; (c) providing an additive selected to assist in the removal of selected contaminants from the gas phase effluent stream; (d) introducing the activated carbon particles and the additive into the gas-phase exhaust stream, thereby adsorbing at least a portion of the selected contaminants onto the activated carbon particles, thereby producing contaminant-adsorbed carbon particles in the gas-phase exhaust stream; (e) separating a portion of the contaminant-adsorbed carbon particles from the gas-phase exhaust stream to produce a contaminant-reduced gas-phase exhaust stream.

[0446] 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.

[0447] The selected contaminant (in the gas phase exhaust stream) may be a metal, such as mercury, boron, selenium, or arsenic, or any compound, salt, or mixture thereof. The selected contaminant may 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 a greater amount 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.

[0448] A hazardous air pollutant is a pollutant that causes 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 as a possible selected pollutant in this context.

[0449] Volatile organic compounds (some of which are also hazardous air pollutants) are organic chemicals that have high vapor pressures at normal room temperature conditions. 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 definition of volatile organic compounds is found in 40 CFR Section 51.100, which is incorporated herein by reference in its entirety.

[0450] A non-condensable gas is a gas that does not condense under normal room temperature conditions and may include, but is not limited to, oxides of nitrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, sulfur dioxide, sulfur trioxide, methane, ethane, ethylene, ozone, ammonia, or combinations thereof.

[0451] Multiple contaminants can be removed by the disclosed activated carbon particles. In some embodiments, the contaminant-adsorbed carbon particles include at least two contaminants, at least three contaminants, or more. The activated carbon disclosed herein can allow for the control of multiple contaminants as well as the control of specific target contaminants (e.g., selenium).

[0452] 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.

[0453] In some embodiments, the additive for the activated carbon is selected from an acid, a base, a salt, a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof. In certain embodiments, the additive is selected from magnesium, manganese, aluminum, nickel, iron, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, 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.

[0454] In some embodiments, the gas phase emissions stream is derived from metal processing, such as the processing of high sulfur-containing metal ores.

[0455] As an exemplary embodiment for mercury control, activated carbon can be injected (such as 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 pneumatically injected as a powder. The injection location can be determined by the existing plant configuration (unless it is a new site) and whether additional downstream particulate matter control equipment is being modified.

[0456] 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 woven filter), (ii) injecting powdered activated carbon downstream of the existing electrostatic precipitator and upstream of a retrofit woven 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. Additionally, the inclusion of iron or iron-containing compounds can separate spent activated carbon solids from other ash, potentially dramatically changing end-of-life options.

[0457] 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.

[0458] In some embodiments, the same physical material can be used in multiple processes, either in an integrated manner or sequence, so 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 that requires carbon but does not require the properties of activated carbon, etc.

[0459] The biogenic activated carbon and principles of the present disclosure can be applied to liquid phase applications including, for example, the treatment 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) at least some amount of a liquid state present.

[0460] In one embodiment, the present disclosure, in some variations, provides a method of using activated carbon to purify a liquid, comprising: (a) providing activated carbon particles recovered from a second reactor; (b) providing a liquid containing at least one selected contaminant; (c) providing an additive selected to assist in the removal of selected contaminants from the liquid; and (d) contacting the liquid with the activated carbon particles and the additive to adsorb at least one selected contaminant onto the activated carbon particles, thereby producing contaminant-adsorbing carbon particles and a contaminant-reducing liquid.

[0461] The additive may be provided as part of the activated carbon particles. Alternatively, the additive may be introduced directly into the liquid. In some embodiments, the additive (which may be the same or different) is introduced both as part of the activated carbon particles and directly into the liquid.

[0462] In some embodiments for liquid phase applications, the additive is selected from an acid, a base, a salt, a metal, a metal oxide, a metal hydroxide, a metal halide, or a combination thereof. For example, the additive can be selected from magnesium, manganese, aluminum, nickel, iron, chromium, silicon, boron, cerium, molybdenum, phosphorus, tungsten, vanadium, iron chloride, iron bromide, magnesium oxide, dolomite, dolomitic lime, fluorspar, 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.

[0463] In some embodiments, the selected contaminant (in the liquid being treated) is a metal, such as a metal selected from arsenic, boron, selenium, or 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 an amount greater 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.

[0464] The liquid to be treated may typically be aqueous, but this is not required by the principles of the present disclosure. In some embodiments, the liquid is treated with activated carbon particles in a fixed bed. In other embodiments, the liquid is treated with activated carbon particles in solution or in a moving bed.

[0465] In one embodiment, the present disclosure provides a method for removing at least a portion of a sulfur-containing contaminant 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 to adsorb or absorb at least a portion of the sulfur-containing contaminants onto or within the activated carbon particles.

[0466] In some embodiments, the sulfur-containing contaminant is selected from elemental sulfur, sulfate, sulfurous acid, sulfur dioxide, sulfur trioxide, sulfate anion, bisulfate anion, sulfite anion, bisulfite anion, thiol, sulfide, disulfide, polysulfide, thioether, thioester, thioacetal, sulfoxide, sulfone, thiosulfinate, sulfimide, sulfoximide, sulfondiimine, sulfur halide, thioketone, thioaldehyde, sulfur oxide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, sulfenic acid, sulfonium, oxosulfonium, sulfurfuran, persulfuranes, or combinations, salts, or derivatives thereof. For example, the sulfur-containing contaminant can be sulfate in an anionic or salt form.

[0467] 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 of) a natural body of water, such as a lake, river, or stream.

[0468] 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 water containing sulfate; (c) providing an additive selected to assist in the removal of sulfates from the water; and (d) contacting the water with the activated carbon particles and the additive to adsorb or absorb at least a portion of the sulfate onto or into the activated carbon particles.

[0469] 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 anion. Depending on the pH, sulfate can also be present in the form of sulfate.

[0470] The water may be derived from some 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.

[0471] When water is treated with activated carbon, there may be water filtration, water permeation, or direct addition of activated carbon particles to the water (with sedimentation, clarification, etc.). When permeation is used, activated carbon may be used in several ways within or to assist 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 the membrane for permeation.

[0472] 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 comprising at least one sulfur-containing contaminant; (c) providing an additive selected to assist in the removal of sulfur-containing contaminants from the gas phase exhaust stream; and (d) introducing activated carbon particles and an additive into the gas-phase exhaust stream to adsorb or absorb at least a portion of the sulfur-containing contaminants onto the activated carbon particles; (e) separating at least a portion of the activated carbon particles from the gas-phase exhaust stream.

[0473] In some embodiments, the sulfur-containing contaminant is selected from elemental sulfur, sulfuric acid, sulfurous acid, sulfur dioxide, sulfur trioxide, sulfate anion, bisulfate anion, sulfite anion, bisulfite anion, thiol, sulfide, disulfide, polysulfide, thioether, thioester, thioacetal, sulfoxide, sulfone, thiosulfinate, sulfimide, sulfoximide, sulfondiimine, sulfur halides, thioketone, thioaldehyde, sulfur oxide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, sulfenic acid, sulfonium, oxosulfonium, sulfurane, persulfuranes, or combinations, salts, or derivatives thereof.

[0474] Generally speaking, the disclosed activated carbons can be used in any application where conventional activated carbons may 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.

[0475] 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 packed column comprises the disclosed activated carbon. In such embodiments, the biogenic activated carbon has size characteristics suitable for the particular packed bed or packed 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.

[0476] Use of Bio-Carbon Pellets in Metal Oxide Reduction There are various embodiments in which biocarbon pellets or a finely divided form thereof are fed into a metal ore furnace or a chemical reduction furnace.

[0477] The metal ore furnace or chemical reduction furnace may 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 or derivative thereof.

[0478] Metal ore furnaces or chemical reduction furnaces can be arranged horizontally, vertically, or inclined. The flow of solids and fluids (liquid or gas) can be co-current or counter-current. The solids in the furnace can be in a fixed bed or a fluidized bed. Metal ore furnaces or chemical reduction furnaces can be operated at a variety of process conditions of temperature, pressure, and residence time.

[0479] Some variations of the invention 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 sintering plants, for example in base metal smelting.

[0480] The term "blast" refers to the forced or fed combustion air above atmospheric pressure. In a blast furnace, metal ore, carbon (e.g., in this disclosure, bioagent or its derivatives), and usually flux (e.g., limestone) are continuously fed 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 usually molten metal and slag phases removed from the bottom, and waste gases (reduced off-gas) exiting the top of the furnace. The downward flow of metal ore along the flux in countercurrent contact with the rising flow of hot CO2-enriched gas allows for efficient chemical reactions that reduce the metal ore to metal.

[0481] Air furnaces (such as reverberatory furnaces) are usually naturally aspirated by convection of hot gases in the chimney flue. According to this broad definition, bloomery furnaces for iron, blowing houses for tin, and smelting plants for lead are classified as blast furnaces.

[0482] Blast furnaces remain an important part of modern iron production. Modern furnaces are highly efficient and include cowper stoves that preheat the incoming blast air with waste heat from the flue gases, and recovery systems that extract heat from the hot gases leaving the furnace. Blast furnaces are typically built in the form of tall structures lined with refractory bricks and contoured to expand as the feed material heats on its descent, then reduce in size as melting begins to occur.

[0483] In some embodiments for iron production, biocarbon pellets, iron ore (iron oxide), and limestone flux are charged to the top of a blast furnace. The iron ore or limestone flux can be incorporated into the biocarbon pellets. Optionally, the biocarbon pellets are reduced in size before being fed to the blast furnace. For example, the biocarbon pellets can be pulverized into a powder that is fed to the blast furnace.

[0484] Blast furnaces can be configured to allow hot, dirty gases with high carbon monoxide content to exit the furnace throat, while bleeder valves can protect the top of the furnace from sudden gas pressure surges. Coarse particles in the exhaust gases can settle and be disposed of, while the gases can flow through a venturi scrubber or electrostatic precipitator or gas cooler to reduce the temperature of the cleaned gases. A casting chamber at the bottom of the furnace houses equipment for casting liquid iron and slag. The taphole can be drilled into 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 have been tapped, the taphole can be plugged with fireclay. Nozzles called tuyere are used to deliver hot air to increase the efficiency of the blast furnace. The hot air is directed into the furnace through a cooled tuyere near the base. The hot air temperature can be, for example, about 900°C to 1300°C (air temperature). The temperature in the blast furnace can be at least about 2000° C. or higher. Other carbonaceous materials or oxygen can also be injected into the furnace at the tuyere level to combine with the carbon (from the bio-carbon pellets) to release additional energy and increase the percentage of reducing gas present, which increases productivity.

[0485] Blast furnaces operate on the principle of chemical reduction, where 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 usually operate as a continuous countercurrent exchange process.

[0486] Silica is usually 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 downward moving column of metal ores, fluxes, carbon, and reaction products must be porous enough to allow the flue gases to pass through. This requires that the bioreagent carbon be particles large enough (e.g., biocarbon pellets or smaller objects derived from pellets) to be permeable. Thus, the pellets or crushed pellets must be strong enough not to be crushed by the weight of the material above them. In addition to the physical strength of the carbon, it is also preferable that it is low in sulfur, phosphorus, and ash.

[0487] Many chemical reactions occur in a blast furnace. The 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) will have various concentrations of different iron oxides (Fe3O4, Fe2O3, FeO, etc.).

[0488] The main overall chemical reactions producing molten iron in a blast furnace are as follows: Fe2O3+3CO→2Fe+3CO2 This is an endothermic reaction. The reaction occurs in many steps, the first of which is that the preheated blast air blown into the furnace reacts with carbon (e.g., from the biocarbon pellets) to produce carbon monoxide and heat. 2C+O2→2CO

[0489] Hot carbon monoxide is a reducing agent for the iron ore and reacts with the 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

[0490] 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

[0491] Hot carbon dioxide, unreacted carbon monoxide, and nitrogen from the air pass upwardly 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

[0492] The calcium oxide formed by decomposition reacts with various acidic impurities in the iron (especially silica) to form a slag which is mainly calcium silicate, CaSiO3. SiO2+CaO→CaSiO3

[0493] 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

[0494] The carbon dioxide formed in this process can be converted back to carbon monoxide by reacting it with carbon via the reverse Boudouir reaction. C+CO2→2CO

[0495] It is important to note that in the chemical reactions shown above, the reducing gas is not an in situ product in the furnace, but can alternatively or additionally be introduced directly into the blast furnace. Typically, in these embodiments, the reducing gas includes both hydrogen and carbon monoxide, both of which function to chemically reduce metal oxides. Optionally, the reducing gas can be generated separately from the bio-carbon pellets by reforming, gasification, or partial oxidation.

[0496] In a conventional blast furnace, there is no hydrogen available 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 within the bio-carbon pellets fed to the blast furnace if the bio-carbon pellets contain volatile carbon (e.g., heavy tar components) associated with hydrogen. 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 a 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.

[0497] The "pig iron" produced by a blast furnace typically has a relatively high carbon content, around 3-6% by weight. The pig iron can be used to make cast iron. The pig iron produced by the 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 into the liquid pig iron to form crude steel.

[0498] Desulfurization is conventionally performed during transportation of liquid iron to the steel mill by adding calcium oxide, which reacts with the iron sulfides contained in the pig iron to form calcium sulfide. In some embodiments, desulfurization may 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 may 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.

[0499] Other types of furnaces can use other chemical reactions. It will be understood that in chemical conversion of metal oxides to metals using carbon or reducing gas in the conversion, the carbon is preferably renewable carbon. The present disclosure provides renewable carbon in bioreagents produced via pyrolysis of biomass. In certain embodiments, some carbon utilized in the furnace is not renewable carbon. In various embodiments, the percentage of renewable carbon of the total carbon consumed in the metal ore furnace can be at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100%.

[0500] Some variations of the invention utilize a Tecnored furnace, or a variation thereof. The Tecnored process was originally developed by Tecnored Desenvolvimento Tecnologico SA in Brazil and is based on a low-pressure moving bed reduction furnace that reduces cold-bonded, carbon-containing, autogenous, and self-reducing pellets. Reduction is carried out in a low-profile shaft furnace at typical reduction temperatures. The process produces hot metal (typically liquid iron) with high efficiency.

[0501] The 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, sinter plants, and tonnage oxygen plants. The process therefore has much lower operating and investment costs than those of the traditional steelmaking route.

[0502] In this disclosure, the Tecnored process can be adapted for use with bio-reagents in a variety of ways. Some embodiments provide self-reducing aggregates (e.g., bio-carbon pellets) produced from iron ore fines or iron-bearing residues plus a bio-reagent. These materials, mixed with fluxing and binders, are agglomerated and thermally hardened to produce bio-carbon pellets with sufficient strength for the physical and metallurgical demands of the Tecnored process. The produced aggregates are then smelted in a Tecnored furnace. The fuel for the Tecnored furnace can also be the bio-carbon pellets themselves.

[0503] By combining fine particles of iron oxide with the 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 autoreduced briquette can be designed to contain sufficient reducing agent to fully reduce the contained iron-bearing raw material, and optionally a desired flux can be used to provide slag chemistry. The autoreduced briquette is hardened at low temperature before being fed into the furnace. The heat required to drive the reaction within the autoreduced briquette is provided by a bed of solid fuel, which can also be in the form of briquettes, onto which the autoreduced briquette is fed into the furnace.

[0504] 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 Boudoir reaction (C+CO2→2CO) is prevented, saving energy. Post-combustion in this zone of the furnace burns the CO, which provides the energy for pre-heating and reduction of the charge. Inside the pellets, the following reactions take place at a very fast rate: Fe x O y +yCO →xFe+yCO2 yCO2+yC=2yCO (wherein x is 1 to typically 5, and y is 1 to typically 7).

[0505] 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 preferably comprises, and more preferably consists essentially of, biocarbon pellets. In this zone, further reduction of residual iron oxide and slagging reactions of gangue material and fuel ash occur in the liquid state. Also, superheating of metal and slag droplets occurs. These superheated metal and slag droplets sink by gravity to the hearth of the furnace and accumulate there.

[0506] This modified Tecnored process uses two different inputs of carbon units: a reductant and a solid fuel. The reductant is traditionally coal fines, but in this disclosure, the reductant can include finely ground bio-carbon pellets. The self-reducing aggregates can be bio-carbon pellets as disclosed herein. The amount of carbon fines required is established by the C / F (carbon to ore fines) ratio, which is preferably selected to achieve complete reduction of the metal oxides.

[0507] The solid fuel does not have to be in the form of a fine powder. For example, the solid fuel can be in the form of agglomerates, such as about 40-80 mm in size, to address the physical and thermal needs required from the solid fuel in the Tecnored process. These agglomerates can be made by breaking down (e.g. crushing) biocarbon pellets, but not completely pulverized. The solid fuel is charged through a side feeder (to avoid the endothermic Boudoir reaction in the upper shaft) and provides most 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 the gasification of the solid fuel in the hearth is burned (2CO+O2→2CO2).

[0508] In a particular exemplary embodiment, the modified Tecnored process involves pelletizing iron ore fines having a size less than 140 mesh, bio-reactant fines having a size less than 200 mesh, and flux such as hydrated lime having a size less than 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 about 30-40 minutes. Bio-reagent in the form of solid fuel in the size range of 40mm-80mm is fed into the furnace below the hot pellet area using a side feeder. Hot blast air at about 1150°C blows through tuyeres located on the side of the furnace to provide combustion air for the bio-carbon. A small amount of furnace gas is flowed through the side feeder for use in drying and pre-heating the solid fuel. Cold blast air blows at a higher point to promote post-combustion of CO in the upper shaft. The hot metal produced 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. Hot metal typically contains about 3-5% carbon by weight.

[0509] 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 to initiate 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 (+yH2→xFe+yH2O). 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 the blast furnace with aspects of the Tecnored furnace, whereby self-reducing pellets or briquettes are utilized in addition to the use of reducing gas in the furnace.

[0510] 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 invention may be applied to essentially any furnace or process that uses carbon somewhere in the process of making metals from metal ores.

[0511] It will also be observed that some processes utilize bio-carbon pellets, some utilize reducing gas, and some utilize both bio-carbon pellets and reducing gas. The processes provided herein can produce both solid bio-carbon pellets and reducing gas. In some embodiments, only solid bio-carbon pellets are used in the metal ore conversion process. In other embodiments, only reducing gas is used in the metal ore conversion process. In still other embodiments, both bio-carbon pellets and reducing gas are used in the metal ore conversion process. In those embodiments using both sources of renewable carbon, the percentage of total carbon usage in the metal ore conversion from 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%. The other carbon usage is preferably from bio-carbon pellets. Alternatively, some or all of the other carbon usage can be from traditional carbon inputs such as coal fines.

[0512] Conversion of biocarbon pellets into reducing gas Some variations employ bio-carbon pellets to generate reducing gas, which can be utilized in situ in the process or can be captured and sold.

[0513] The optional production of a reducing gas (also referred to herein as a "bioreductant gas") will now be further described. The conversion of the biocarbon pellets to a reducing gas takes place in a reactor that can be referred to as a bioreductant formation unit.

[0514] A reactant is used to react with the biocarbon pellets 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 the second reactor. Oxygen or oxygen-enriched air can be added to cause an exothermic reaction, such as partial or total oxidation of carbon with oxygen; 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, for example, by reducing the amount of CO2, pyrolysis products, tars, aromatics, or other undesirable products.

[0515] In some embodiments, water vapor is a preferred reactant. Water vapor (i.e., H2O in the vapor phase) can be introduced into the reactor in one or more input streams. Water vapor can include water vapor generated by moisture contained in the biocarbon pellets, as well as water vapor generated by any chemical reaction that produces water.

[0516] All references herein to "ratios" of chemical species are references to molar ratios unless otherwise indicated. For example, a H2 / CO ratio of 1 means 1 mole of hydrogen per mole of carbon dioxide.

[0517] 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 the cellulose repeating unit (CH) found in cellulosic feedstocks. 10 O5) is shown below. Similar reactions can occur with any carbon-containing feedstock, including biocarbon pellets. Steam reforming C6H 10 O5+H2O→6CO+6H2 Partially oxidized C6H 10 O5+1 / 2O2→6CO+5H2 Water gas shift CO+H2O⇔H2+CO2 Complete Combustion C6H 10 O5+6O2→6CO2+5H2O

[0518] The bioreductant formation unit is any reactor capable of causing at least one 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.

[0519] In some embodiments, the total amount of steam as a 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.

[0520] The amount of water steam added to the second reactor can vary depending on factors such as the conditions in the pyrolysis reactor. If pyrolysis produces carbon-enriched solid material, generally more water steam (or more oxygen) is used to add the necessary H and O atoms to the available C to produce CO and H2. From a system-wide perspective, the moisture contained in the biocarbon pellets can be considered in determining how much additional water (steam) to add in the process.

[0521] Exemplary ratios of oxygen to water vapor (O2 / H2O) in the second reactor are equal to or less than about any of 2, 1.5, 1, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01, or less. If the ratio of O2 / H2O is greater than at least 1, the combustion reaction begins to dominate over partial oxidation, which can result in an undesirably low CO / CO2 ratio.

[0522] In some embodiments, oxygen without water vapor is used as a reactant. Oxygen can be added in substantially pure form or can be optionally fed to the process via the addition of oxygen-enriched air. In some embodiments, air that is not enriched in oxygen is added. In other embodiments, enriched air from off-spec or recycle streams can be used, which can be, for example, streams from a nearby air separation plant. In some embodiments, using enriched air with reduced amounts of N2 (i.e., less than 79% by volume) results in less N2 in the resulting reduction gas. Since removal of N2 can be expensive, a method of producing a reduction gas with less or no N2 is typically desired.

[0523] 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, such as 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 water vapor addition rates) tends to produce 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.

[0524] A catalyst may optionally be utilized in the reactor to generate the reducing gas. Catalysts may 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 supported on NiSMM, iron hydroxy oxides, iron nitrates, iron-calcium impregnated salts, nickel uranyl oxide, sodium fluoride, and cryolite.

[0525] 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).

[0526] 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.

[0527] The addition of the catalyst can be done 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 injecting such a slurry directly into the vessel. In some embodiments, the catalyst is added to the water vapor and the water vapor / catalyst mixture is added to the system. In these embodiments, the added catalyst can be at or near its equilibrium solubility in the water vapor or can be introduced as particles entrained in the water vapor and thereby introduced into the system.

[0528] Materials can generally be conveyed in and out of the reactor by single screws, twin screws, rams, etc. Materials can be mechanically conveyed by physical forces (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. Utilizing a fixed bed of biocarbon pellets in the reactor may be preferred, especially in embodiments using a bed of metal oxide disposed above a bed of biocarbon pellets, which needs to be mechanically robust.

[0529] In some embodiments, the reactor uses gasification of biocarbon pellets, or powders formed therefrom, to produce the reducing gas. Gasification is carried out at high temperatures, typically from about 600°C to about 1100°C. Less reactive bioreagents require higher operating temperatures. The amount of reactant (e.g., air, oxygen, enriched air, or oxygen-steam mixture) introduced will typically be the primary factor controlling the gasification temperature. Operating pressures from atmospheric pressure up to about 50 bar have been used in biomass gasification. Gasification also requires reactants, typically air, high purity oxygen, steam, or some mixture of these gases.

[0530] Gasifiers can be differentiated based on the means of supporting solids within the vessel, the direction of flow of both solids and gases, and the method of supplying heat to the reactor. Whether the gasifier is operated 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.

[0531] 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, pulverized, and the biocarbon pellets can be gasified. The biocarbon pellets can be directly gasified using a fixed bed gasifier, without necessarily reducing the size of the pellets.

[0532] 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 in commercial use.

[0533] Directly heated gasifiers carry out endothermic and exothermic gasification reactions in a single reaction vessel and do not require additional heating. In contrast, indirectly heated gasifiers require an external heat source. Indirectly heated gasifiers generally use two vessels. The first vessel gasifies the feed with steam (an endothermic process). Heat is provided by circulating a heat transfer medium, usually sand. The reducing gas and solid char produced in the first vessel are separated along with the sand. The mixed char and sand are fed to a second vessel where the char is combusted with air to heat the sand. The hot sand is circulated back to the first vessel.

[0534] The biocarbon pellets 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 typically allow 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.

[0535] In some embodiments, the feed to the gasifier is biocarbon pellets with 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 higher.

[0536] In some embodiments, the feed to the gasifier is biocarbon pellets with low hydrogen content. The resulting reduced gas is expected to have a relatively low H2 / CO ratio. For downstream processes requiring 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 may also contribute to temperature moderation through endothermic consumption via steam reforming chemistry. In steam reforming, H2O reacts with carbon or hydrocarbons such as tar or benzene / toluene / xylene to produce reduced gas and lower the adiabatic gasification temperature.

[0537] 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 is preferably adjusted to a temperature low enough so that the 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.

[0538] 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. Correct velocities must be maintained to ensure proper fluidization.

[0539] 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.

[0540] A circulating fluidized bed gasifier can be used in which gas, sand, and feedstock (e.g., crushed or pulverized biocarbon pellets) 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.

[0541] In some embodiments where a countercurrent fixed bed gasifier is used, the reactor consists of 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.

[0542] In some embodiments where a co-current fixed bed gasifier is used, the reactor is similar to the 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.

[0543] In some embodiments where a fluidized bed reactor is used, the feedstock is fluidized in recycle gas, oxygen, air, or steam. The ash can be removed dry or as heavy agglomerates that are defluidized. Recycle of solids 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.

[0544] In some embodiments where an entrained flow gasifier is used, the biocarbon pellets are pulverized and 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 can reduce the amount of tar and methane in the reducing gas.

[0545] Entrained flow reactors remove most of the ash as slag because the operating temperatures can typically be well above the ash melting temperature. A smaller portion of the ash is produced as very fine dry fly ash or as a fly ash slurry. Some entrained bed reactors have internal water or steam cooled walls that are covered with partially solidified slag.

[0546] The gasifier chamber can be designed to keep the carryover of solids downstream work at a level suitable for heat recovery by appropriate configuration of the freeboard or use of internal cyclones. Unreacted carbon can be drawn off from the bottom of the gasifier chamber, cooled and recovered.

[0547] 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.

[0548] In some embodiments, a bubbling fluidized bed devolatilization reactor is utilized. 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. Steam, oxygen or air can also be introduced into the second reactor. The second can be designed to keep solids carryover at a level suitable for downstream heat recovery by appropriate configuration of the freeboard or use of an internal cyclone. Unreacted char is withdrawn from the bottom of the devolatilization chamber, cooled, and can then be fed to a utility boiler to recover the remaining heating value of this stream.

[0549] If a fluidized bed gasifier is used, the feedstock may be introduced into a bed of hot sand fluidized by a gas, such as recirculating gas. References herein to "sand" also include similar substantially inert materials, such as glass particles, recovered ash particles, etc. The high rate of heat transfer from the fluidized sand may result in rapid heating of the feedstock. There may be some ablation due to friction with the sand particles. Heat may be provided by heat exchanger tubes through which the hot combustion gases flow.

[0550] A circulating fluidized bed reactor 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.

[0551] In some embodiments where a countercurrent fixed bed reactor is used, the reactor consists of 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.

[0552] In some embodiments where a co-current fixed bed reactor is used, the reactor is similar to the counter-current type, but the gasifier 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 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. Tar levels are expected to be lower in this configuration than when using a counter-current type, since the tar passes through the hot carbon bed.

[0553] In some embodiments where a fluidized bed reactor is used, the feedstock is fluidized in recycle gas, oxygen, air, or steam. Ash is removed as heavy agglomerates that are dried or defluidized. Recycle of solids or subsequent combustion can be used to increase conversion.

[0554] To improve heat and mass transfer, water can be introduced into the reactor using a nozzle, which is generally a mechanical device designed to control the direction or characteristics of a fluid flow as it enters an enclosed chamber or pipe through an orifice. The nozzle can reduce the water droplet size to produce a fine spray of water. Nozzles can be selected from atomizing nozzles (similar to fuel injectors), swirl nozzles that spray liquid tangentially, and the like.

[0555] Water sources can include direct piping from process condensate, other recycle water, wastewater, make-up water, boiler feed water, city water, etc. The water can optionally be first washed, purified, treated, ionized, distilled, etc. When several water sources are used, various volume ratios of the water sources are possible. In some embodiments, some or all of the water for the second reactor is wastewater.

[0556] In some variations, the reducing gas 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.

[0557] Some embodiments include a reduction gas purification unit. 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. In some embodiments, the acid gas removal unit can be any means known in the art for removing H2S, CO2, or other acid gases from the reduction gas.

[0558] Examples of acid gas removal steps include removing CO2 with one or more solvents for CO2 or removing CO2 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).

[0559] The reducing gas produced as described in accordance with the present invention 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-C 15 It can be converted to hydrocarbons, diesel fuel, gasoline, wax, or olefins; mixed alcohols by various catalysts; isobutane by isosynthesis; ammonia by hydrogen production following 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 to energy using energy conversion devices such as solid oxide fuel cells, Stirling engines, microturbines, internal combustion engines, thermoelectric generators, scroll expanders, gas burners, or thermophotovoltaic devices. EXAMPLES

[0560] Examples 1-6 demonstrate that biocarbon pellets can be made with adjustable HGI values ​​in accordance with the disclosure set forth herein. Without being limited to theory, coarser, less cooked materials result in lower HGI, while finer, more cooked materials result in higher HGI.

[0561] Example 1: Biocarbon pellets with HGI of 30 A first mixture of hardwood and softwood is pyrolyzed, thereby producing a first bio-carbon reagent at a pyrolysis temperature of 371° C. and a pyrolysis time of 15-30 minutes. A second mixture of hardwood and softwood is pyrolyzed, thereby producing a second bio-carbon reagent at a pyrolysis temperature of 650° C. and a pyrolysis time of 15-30 minutes. The lower pyrolysis temperature of the second bio-reagent results in a relatively lower fixed carbon content. The first bio-carbon reagent and the second bio-reagent are blended in a ratio of about 70% by weight of the first bio-reagent and about 30% by weight of the second bio-reagent, thereby forming a combined bio-reagent. 320 lbs (dry basis) of the combined bio-reagent is combined with 52 lbs of starch binder, thereby forming a mixture. The mixture is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device including a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to about 5% moisture by weight. The pellets have an average Hardgrove Crushability Index of 30, as determined according to ASTM-Standard D409 / D409M and shown in the data sheet in Figure 3. Note that the X labels in Figure 3 indicate that a particular measurement was not performed.

[0562] Example 2: Biocarbon pellets with HGI of 40 Douglas fir wood is pyrolyzed, thereby producing a biocarbon reagent, at a pyrolysis temperature of 650°C and a pyrolysis time of 15-30 minutes. 320 lbs of bioreagent (dry basis) are combined with 50 lbs of starch binder, thereby forming a mixture. The mixture is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device including a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to a moisture content of about 11% by weight. The composition and other properties are shown in the data sheet in Figure 4. The Hardgrove Friability Index is determined according to ASTM-Standard D409 / D409M and is measured to be 40. Note that the X labels in Figure 4 indicate that the specific measurement was not performed.

[0563] Example 3: Biocarbon pellets with HGI of 45 Douglas fir wood is pyrolyzed, thereby producing biocarbon reagent, at a pyrolysis temperature of 650°C and a pyrolysis time of 15-30 minutes. 320 lb of bioreagent (dry basis) is combined with 40 lb of starch binder to form a mixture. The mixture is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device consisting of a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to a moisture content of about 10% by weight. The composition and other properties are shown in the data sheet in Figure 5. The Hardgrove Friability Index is determined according to ASTM-Standard D409 / D409M and is measured to be 45. Note that the X labels in Figure 5 indicate that a particular measurement was not performed.

[0564] Example 4: Biocarbon pellets with HGI of 49 Douglas fir wood is pyrolyzed, thereby producing a biocarbon reagent, at a pyrolysis temperature of 650°C and a pyrolysis time of 15-30 minutes. 320 lb of bioreagent (dry basis) is combined with 30 lb of starch binder to form a mixture. The mixture is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device consisting of a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to a moisture content of about 9% by weight. The composition and other properties are shown in the data sheet in Figure 6. The Hardgrove Grinderability Index is determined according to ASTM-Standard D409 / D409M and is measured to be 49. Note that the X labels in Figure 6 indicate that a particular measurement was not performed.

[0565] Example 5: Biocarbon pellets with HGI of 71 Red pine wood is pyrolyzed, thereby producing biocarbon reagent, at a pyrolysis temperature of 650°C and a pyrolysis time of 15-30 minutes. 320 lb of bioreagent (dry basis) is combined with 24 lb of starch binder to form a mixture. The mixture is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device consisting of a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to a moisture of about 7% by weight. The composition and other properties are shown in the data sheet in Figure 7. The Hardgrove Grinderability Index is determined according to ASTM-Standard D409 / D409M and is measured to be 71. Note that the X labels in Figure 7 indicate that the specific measurement was not performed.

[0566] Example 6: Biocarbon pellets with HGI of 117 A first mixture of hardwood and softwood is pyrolyzed, thereby producing a first bio-carbon reagent at a pyrolysis temperature of 371° C. and a pyrolysis time of 15-30 minutes. A second mixture of hardwood and softwood is pyrolyzed, thereby producing a second bio-carbon reagent at a pyrolysis temperature of 650° C. and a pyrolysis time of 15-30 minutes. The lower pyrolysis temperature of the second bio-reagent results in a relatively lower fixed carbon content. The first bio-carbon reagent and the second bio-reagent are blended in a ratio of about 90% by weight of the first bio-reagent and about 10% by weight of the second bio-reagent to form a combined bio-reagent. The combined bio-reagent contains 320 lb (dry basis) of the first bio-reagent and 36 lb (dry basis) of the second bio-reagent, the second bio-reagent containing a self-generated lignin binder. The combined bio-reagent is mechanically processed using an extruder to form a powder. The powder is pelletized using a pelletizing device consisting of a vertical ring die pelletizer, thereby producing pellets having a diameter of about 8 mm. The pellets are dried to a moisture content of about 8% by weight. The Hardgrove Friability Index is determined according to ASTM-Standard D409 / D409M and is measured to be 117, as shown in the data sheet in Figure 8. Note that the X label in Figure 8 indicates that a particular measurement was not performed.

[0567] In this detailed description, reference is made to several embodiments of the invention and non-limiting examples of how the invention can be realized and practiced. Other embodiments that do not provide all of the features and advantages described herein can be utilized without departing from the spirit and scope of the invention. The invention incorporates routine experimentation and optimization of the methods and systems described herein. Such modifications and variations are considered to be within the scope of the invention as defined by the claims.

[0568] 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 herein.

[0569] Where the methods and steps described above indicate certain events occurring in a particular order, those skilled in the art will recognize that the order of certain things can be altered and that such alterations are in accordance with variations of the invention. Additionally, some of the steps may be performed simultaneously in parallel processes where possible, or may be performed sequentially.

[0570] Thus, to the extent there are variations of the present invention that are within the spirit of this disclosure or are equivalents of the invention found in the appended claims, it is intended that this patent cover those variations as well. The present invention is limited only by the scope of the claims.

Claims

1. A biocarbon pellet comprising: (a) 35% to 99% by weight of a bio-reagent, the bio-reagent comprising at least 60% by weight carbon on a dry basis; (b) 0% to 35% by weight of water; (c) 1% to 30% by weight of a binder; 2. A bio-carbon pellet, wherein said bio-carbon pellet is characterized by a Hardgrove Crushability Index of at least 30.

2. 2. The bio-carbon pellet of claim 1, wherein the bio-reagent comprises at least 70, 80 or 90% carbon by weight on a dry basis.

3. 2. The bio-carbon pellet of claim 1, wherein the bio-reagent comprises at least 50, 75 or 90% fixed carbon by weight on a dry basis.

4. The carbon is １４ C / １２ 2. The biocarbon pellets of claim 1, which are at least 50%, 80%, 90% or 95% renewable as determined from C isotope ratio measurements.

5. The carbon is １４ C / １２ 2. The biocarbon pellets of claim 1, which are fully renewable as determined from C isotope ratio measurements.

6. 2. The bio-carbon pellet of claim 1, wherein the bio-reagent comprises, on a dry basis, 75% to 94% by weight carbon, 3% to 15% by weight oxygen, and 1% to 10% by weight hydrogen.

7. 2. The bio-carbon pellet of claim 1, wherein the bio-carbon pellet contains 1% to 30% moisture by weight.

8. 2. The bio-carbon pellet of claim 1, wherein the bio-carbon pellet comprises 2% to 25% by weight of the binder.

9. 10. The bio-carbon pellet of claim 1, wherein the binder reduces the reactivity of the bio-carbon pellet compared to an otherwise identical bio-carbon pellet lacking the binder.

10. The bio-carbon pellet according to claim 9, wherein the reactivity is thermal reactivity.

11. 11. The bio-carbon pellet of claim 10, wherein the bio-carbon pellet has a lower self-heating compared to an otherwise equivalent carbon pellet that does not include the binder.

12. 10. The biocarbon pellet of claim 9, wherein the reactivity is chemical reactivity with oxygen, water, hydrogen, carbon monoxide or a metal; optionally, the reactivity is chemical reactivity with a metal and the metal is iron.

13. The bio-carbon pellet of claim 1 , wherein the bio-reagent comprises pores and the binder is contained within the pores.

14. The bio-carbon pellet of claim 1 , wherein the binder is disposed on a surface of the bio-carbon pellet.

15. 2. The bio-carbon pellet of claim 1, wherein the bio-reagent comprises pores and the binder is contained within the pores of the bio-reagent and disposed on a surface of the bio-carbon pellet.

16. 16. The biocarbon pellet of any one of claims 1 to 15, wherein the Hardgrove Crushability Index is at least 40, 50, 60, 70, 80, 90 or 100.

17. The biocarbon pellet according to any one of claims 1 to 15, wherein the Hardgrove Crushability Index is from 30 to 120.

18. 16. The bio-carbon pellets according to any one of claims 1 to 15, wherein the bio-carbon pellets are characterized by a pellet durability index of at least 80%, 85%, 90%, 95% or 99%.

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