Methods and systems for reactive separation of biomass-derived materials in biorefineries

Abstract

The invention provides a method of reactive separation of biomass-derived materials, comprising: providing a pretreated biomass stream that contains a solid phase and a liquid phase; introducing the pretreated biomass stream to a fiber-bed reactive separator (FBRS) that forms a fiber bed; optionally, applying a pre-separation reaction trigger to the fiber bed to cause a chemical reaction of at least one component in situ within the fiber bed; separating the liquid phase from the solid phase, to generate a solid-rich material remaining in the fiber bed and a liquid-rich material directed to an output liquid stream; optionally, applying a post-separation reaction trigger to the solid-rich material, while it is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component; and recovering the solid-rich material from the FBRS. At least one reaction trigger is applied to the FBRS, to cause a selected chemical reaction.

Description

METHODS AND SYSTEMS FOR REACTIVE SEPARATION OF BIOMASS-DERIVED MATERIALS IN BIOREFINERIESPRIORITY DATA

[0001] This international patent application claims priority to U.S. Provisional Patent App. No. 63 / 640,097, filed on April 29, 2024, which is hereby incorporated by reference herein.FIELD

[0002] The present invention generally relates to processes for efficiently converting lignocellulosic biomass into sugars, biochemicals, biofuels, and biomaterials.BACKGROUND

[0003] Lignocellulosic biomass is the most abundant renewable material on the planet and has long been recognized as a potential feedstock for producing chemicals, fuels, and materials. Lignocellulosic biomass normally comprises primarily cellulose, hemicellulose, and lignin. Cellulose and hemicellulose are natural polymers of sugars, and lignin is an aromatic / aliphatic hydrocarbon polymer reinforcing the entire biomass network.

[0004] Biomass refining (or biorefining) has become prevalent in the world’s economy. Cellulose fibers and sugars, hemicellulose sugars, lignin, alcohols, acids, olefins, syngas, and derivatives of these intermediates are being utilized for chemical and fuel production. Integrated biorefineries are capable of processing incoming biomass much the same as petroleum refineries now process crude oil. Underutilized lignocellulosic biomass feedstocks have the potential to be much cheaper thanpetroleum, on a carbon basis, as well as much better from an environmental life-cycle standpoint — including the potential for net-zero-equivalent carbon dioxide emissions from a biorefinery.

[0005] There is currently high interest in addressing climate change by sequestering carbon dioxide (CO2). However, CO2 sequestration comes at a high cost and safety risk, including risk of accidental CO2 release at high concentrations from underground reservoirs. Investment is taking place in ventures that aim to pull CO2 out of the atmosphere using complicated and extraordinarily expensive reaction or separation systems. Yet, such systems already exist — in the form of plants that naturally utilize photosynthesis to consume CO2 and form plant biomass. It is therefore highly desirable to use biomass, and especially lignocellulosic biomass, to create a sustainable CO2 cycle.

[0006] Broadly speaking, in a biorefinery, a biomass feedstock may be combusted to energy, pyrolyzed to biochar, gasified to syngas, hydrolyzed to sugars, mechanically refined to nanocellulose or other specialty celluloses, or a combination thereof. In essentially all these processes with the possible exception of combustion, an initial pretreatment of the biomass is necessary or desirable to improve the yield of desired products. Pretreatment is especially important when forming sugars and / or nanocellulose from biomass.

[0007] “Pretreatmenf ’ (or equivalently, “digestion”) refers to one or more chemical or physical processes that convert lignocellulosic biomass from its native form, which is recalcitrant to hydrolysis, into a form for which a downstream conversion (e.g., enzymatic hydrolysis, chemical catalysis, anaerobic digestion, etc.) is more effective. Because biomass is inherently difficult to efficiently convert via cellulose and / or hemicellulose hydrolysis, essentially any biomass-conversion process utilizing hydrolysis will benefit from an initial pretreatment of the biomass using a pretreatment chemical — such as water, an acid catalyst, a base catalyst, a solvent, or a combination thereof, for example.

[0008] Biomass pretreatment usually results in a mixture of solids and liquids. For almost all downstream applications, economically efficient separation of solids and liquids is necessary. Many lignocellulosic conversion processes require a postdigestion solid / liquid separation and optional wash to separate the digested fiber(largely cellulose) from the digestion liquor (largely hemicellulose, soluble lignin materials, and digestion chemicals). This separation is a significant contributor to both the capital cost and operating cost of the process. Digested fiber usually needs to be processed to ensure: (1) the purity of the cellulose and / or the resulting hydrolyzed cellulose saccharide stream; (2) the purity of the liquid phase containing the digestion chemicals, solubilized hemicellulose, and / or lignin; and (3) the efficient recovery of the digestion chemicals for recycle and of all biomass fractions for further processing. The separation can be challenging, as the digested fiber is very often small, pliable, and sometimes structurally weak. Screw presses are often ineffective, because weak fibers tend to form a poor plug at the discharge of the screw press — leading to high liquid retention in the cake, if a plug can be formed at all. Furthermore, due to the broad particle-size distribution and deformable nature of the solids, the resulting cake tends to be closed with a low permeability, rendering many separation techniques costly or impractical.

[0009] Improvements in solid-liquid separations are needed for biorefineries that convert biomass into useful products.SUMMARY

[0010] The present invention addresses the aforementioned needs in the biorefinery art.

[0011] In some variations, the present invention provides a method of reactive separation of biomass-derived materials, the method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquidphase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator, wherein at least one of steps (c) or (e) is conducted.

[0012] In some embodiments, the pretreated biomass stream is a pretreated lignocellulosic biomass stream, such as pretreated wood chips.

[0013] In some embodiments, the pretreated biomass stream is a slurry containing the solid phase and the liquid phase. In other embodiments, the pretreated biomass stream is in the form of wet solids in which the liquid phase does not form a free liquid phase within the solid phase.

[0014] The pretreated biomass stream may further comprise one or more process aids. Exemplary process aids include filter aids, such as diatomaceous earth or silica (which may be derived from biomass ash).

[0015] In some embodiments, the first biomass-derived material is a cellulose- rich material. In other embodiments, the first biomass-derived material is a ligninrich material. The first biomass-derived material may have substantial quantities of both cellulose and lignin, or substantial quantities of all of cellulose, hemicellulose, and lignin.

[0016] In some embodiments, the second biomass-derived material is a hemicellulose-rich material. In other embodiments, the second biomass-derived material is a lignin-rich material.

[0017] In some embodiments, the fiber bed is an immobilized fiber bed. In other embodiments, the fiber bed is a moving fiber bed.

[0018] In some embodiments, the fiber-bed reactive separator is a filter press. The filter press may be a squeeze-plate filter press containing a plurality of immobilized fiber beds spaced apart by plates and / or membranes, for example.

[0019] In some embodiments, the liquid phase further comprises a hydrolysis catalyst. The hydrolysis catalyst may be selected from the group consisting of sulfur dioxide, sulfonic acid, lignosulfonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, phosphoric acid, nitric acid, carbonic acid, and combinations thereof.

[0020] In some embodiments, the liquid phase further comprises a solvent for lignin. The solvent for lignin may be a Ci-Ce alcohol, such as methanol, ethanol, or a combination thereof.

[0021] In some embodiments, the liquid phase further comprises a sulfonic acid, a lignosulfonic acid, a Ci-Ce organic acid, a fatty acid, a Ci-Ce aldehyde, a Ci- Ce ketone, a Ci-Ce polyol, or a combination thereof.

[0022] In some embodiments, the method further comprises, following step(b), mechanically squeezing the fiber bed to enhance separation of the liquid phase from the solid phase.

[0023] Mechanical squeezing may be conducted between steps (b) and (c). Alternatively, or additionally, mechanical squeezing may be conducted during step(c). Alternatively, or additionally, mechanical squeezing may be conducted between steps (c) and (d). Alternatively, or additionally, mechanical squeezing may be conducted during step (d). Alternatively, or additionally, mechanical squeezing may be conducted after step (d), such as during step (e) or after step (e).

[0024] In some embodiments, mechanical squeezing is accomplished using a squeeze liquid that applies pressure directly to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze liquid that enters a membrane, which applies pressure to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze gas that applies pressure directly to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze gas that enters a membrane, wherein the membrane applies pressure to the fiber bed. In some embodiments, mechanical squeezing is accomplished by physical force applied between a plate or membrane and the fiber bed.

[0025] In some embodiments, the method further comprises, following step (b), blowing a blow gas through the fiber bed, such as to enhance separation of the liquid phase from the solid phase. The blowing may be conducted between steps (b) and (c). Alternatively, or additionally, the blowing is conducted during step (c). Alternatively, or additionally, the blowing is conducted between steps (c) and (d). Alternatively, or additionally, the blowing is conducted during step (d). Alternatively, or additionally, the blowing is conducted after step (d), such as during or after step (e). The blow gas may pass through the fiber bed in cross flow.

[0026] When a blow gas is used, the blow gas may be selected from the group consisting of air, N2, CO2, Ar, He, and combinations thereof, for example. In some embodiments, the blow gas contains no greater than 1 mol% O2. In some embodiments, the blow gas contains no greater than 0.1 mol% O2. In certain embodiments, the blow gas contains no greater than 0.01 mol% O2.

[0027] In some embodiments, the method further comprises, following step (b), washing the fiber bed using a wash fluid, which may enhance separation of the liquid phase from the solid phase. The washing may be conducted between steps (b) and (c). Alternatively, or additionally, the washing may be conducted during step (c). Alternatively, or additionally, the washing may be conducted between steps (c) and (d). Alternatively, or additionally, the washing may be conducted during step (d). Alternatively, or additionally, the washing may be conducted after step (d), such as during or after step (e). The wash fluid may pass through a core of the fiber bed. The wash fluid may pass through the fiber bed in cross flow.

[0028] In some embodiments, the wash fluid is a wash liquid. The wash liquid may be selected from the group consisting of water, a Ci-Ce alcohol, a Ci-Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a fatty acid, a sulfonic acid, a lignosulfonic acid, and combinations thereof. In certain embodiments, the wash liquid is water. In certain embodiments, the wash liquid is a mixture of water and ethanol. Multiple washing steps may be employed, wherein each of the multiple washing steps uses an independently selected wash fluid.

[0029] In some embodiments, the wash fluid is a wash vapor. The wash vapor may be selected from the group consisting of steam, nitrogen, argon, helium, carbondioxide, a Ci-Ce alcohol, a Ci-Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a sulfonic acid, a lignosulfonic acid, and combinations thereof.

[0030] In some embodiments, the fiber-bed reactive separator contains a plurality of immobilized fiber beds spaced apart by plates and / or membranes, and the wash fluid countercurrently passes through the plurality of immobilized fiber beds, relative to flow direction of the liquid phase.

[0031] In some embodiments, the fiber-bed reactive separator contains a plurality of immobilized fiber beds spaced apart by plates and / or membranes, and the wash fluid cocurrently passes through the plurality of immobilized fiber beds, relative to flow direction of the liquid phase.

[0032] In some embodiments, step (c) is conducted while step (e) is not conducted. In some embodiments, step (e) is conducted while step (c) is not conducted. In certain embodiments, both of steps (c) and (e) are conducted in the method.

[0033] In some embodiments, a reaction trigger (i.e., the pre-separation reaction trigger, the post-separation reaction trigger, or both of these) comprises a change in pH within the fiber bed. The change in pH may be accomplished by adding an inorganic acid, an organic acid, or a combination thereof, to the fiber bed, for example. The change in pH may be a pH change of the liquid phase. Alternatively, or additionally, the change in pH may be a pH change associated with the solid phase.

[0034] In some embodiments, the change in pH causes pH to be adjusted to about 4 or less.. In some embodiments, the change in pH causes pH to be adjusted to about 3 or less.. In some embodiments, the change in pH causes pH to be adjusted to about 2 or less.. In certain embodiments, the change in pH causes pH to be adjusted to a pH selected from about 1.0 to about 2.0. In certain embodiments, the change in pH causes pH to be adjusted to a pH selected from about 0.5 to about 1.5.

[0035] In some embodiments, the liquid phase further comprises sulfur dioxide and / or a compound derived therefrom, and the reaction trigger comprises a reduction in pH within the fiber bed. In these embodiments, the reduction in pH shifts a sulfite-species chemical equilibrium toward a higher concentration of free SO2 in the liquid phase. The compound derived therefrom SO2 may be a sulfonic acid, a lignosulfonic acid, a sulfite salt, a bisulfite salt, or a combination thereof, for example.The method may further comprise separating free SO2 from the liquid phase, while the liquid phase is still present in the fiber bed. Alternatively, or additionally, the method may further comprise separating free SO2 from the liquid phase, during step (d). Alternatively, or additionally, the method may further comprise separating free SO2 from the liquid-rich material, after step (d).

[0036] In some embodiments, the method further comprises, following step (b), blowing a blow gas through the fiber bed, wherein free SO2 is captured in the blow gas. In some embodiments, the method further comprises, following step (b), washing the fiber bed using a wash fluid, wherein free SO2 is captured in the wash fluid (e.g., a wash vapor such as steam).

[0037] In some embodiments, a reaction trigger (i.e., the pre-separation reaction trigger, the post-separation reaction trigger, or both of these) comprises a change in temperature of the fiber bed. The change in temperature may cause the temperature of the fiber bed to be from about 50°C to about 200°C, for example.

[0038] In some embodiments, a reaction trigger (i.e., the pre-separation reaction trigger, the post-separation reaction trigger, or both of these) comprises a change in pressure within the fiber bed. The change in pressure may cause the pressure in the fiber bed to be from about 0.1 bar to about 20 bar, for example. In certain embodiments, vacuum (<1 bar gauge pressure) is applied to the fiber bed.

[0039] In some embodiments, a reaction trigger (i.e., the pre-separation reaction trigger, the post-separation reaction trigger, or both of these) comprises addition of a chemical reactant to the fiber bed. The chemical reactant may be added via displacement, absorption, adsorption, chemisorption, or combinations thereof. In some embodiments, the chemical reactant is an inorganic acid. In some embodiments, the chemical reactant is an organic acid. Multiple chemical reactants may be added for a reaction trigger, or for multiple reaction triggers taking place simultaneously or sequentially.

[0040] In some embodiments, the chemical reactant is selected from the group consisting of SO2, CO2, CO, H2, H2O, CH4, NH3, HNO3, H2SO4, H3PO4, HC1, CI2, O2, O3, H2O2, NO, NO2, and combinations thereof.

[0041] In certain embodiments, the chemical reactant is SO2. The SO2 may react with lignin that is, or is contained in, the first biomass-derived material, therebyincreasing sulfur content of the lignin. Alternatively, or additionally, the SO2 may react with lignin that is, or is contained in, the second biomass-derived material, thereby increasing sulfur content of that lignin.

[0042] In some embodiments, cellulose contained in the solid phase reacts with the chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to glucose and / or other cellulose sugars.

[0043] In some embodiments, hemicellulose contained in the solid phase reacts with the chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to xylose and / or other hemicellulose sugars. In some embodiments, hemicellulose contained in the liquid phase reacts with the chemical reactant to generate hemicellulose sugars. In certain embodiments, hemicellulose contained in both the solid and liquid phases reacts with the chemical reactant to generate hemicellulose sugars.

[0044] In some embodiments, the solid-rich material recovered in step (f) has a solids concentration of at least 50 wt% solids. In certain embodiments, the solidrich material recovered in step (f) has a solids concentration of at least 75 wt% solids.

[0045] In some embodiments, the method further comprises recovering a pretreatment chemical from the liquid-rich material, and reusing the pretreatment chemical in pretreatment of fresh biomass.

[0046] In some embodiments, the method further comprises further processing of the solid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, cellulose, nanocellulose, pulp, paper, hemicellulose, lignin, or a combination thereof.

[0047] In some embodiments, the method further comprises further processing of the liquid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, hemicellulose, lignin, or a combination thereof. Preferably, the further processing of the liquid-rich material does not include an evaporation step prior to fermentation and / or catalysis.

[0048] In some embodiments, the method is conducted in batch, such as straight batch or semi-batch.

[0049] In some embodiments, the method is conducted continuously, such as fully continuously or semi-continuously.BRIEF DESCRIPTION OF THE FIGURES

[0050] FIG. 1 is an exemplary block-flow diagram of the processing that takes place in a fiber-bed reactive separator (FBRS), in some embodiments.

[0051] FIG. 2 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0052] FIG. 3 is a block-flow diagram of a method of, and system configured for, non-reactive separation of biomass-derived materials in a comparative process that employs a sequence of centrifuges.

[0053] FIG. 4 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0054] FIG. 5 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0055] FIG. 6 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0056] FIG. 7 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0057] FIG. 8 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0058] FIG. 9 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments.

[0059] FIG. 10 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting primary solid / liquid separation.

[0060] FIG. 11 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting feed of stripping gas to the FBRS that already contains a fiber bed.

[0061] FIG. 12 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting input of a wash liquid that is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed.

[0062] FIG. 13 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting input of a wash liquid that is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed once.

[0063] FIG. 14 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting input of a wash liquid B that is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed three times.

[0064] FIG. 15 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5, depicting input of a reactant or catalyst, combined with a wash liquid, which is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed multiple times.

[0065] FIG. 16 is an exemplary block-flow diagram (snapshot in time, or a subset of total method time) of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 6, depicting input of a catalyst and / or a reactant to the FBRS that already contains a fiber bed, followed by recovery of the catalyst and / or reactant from the FBRS (e.g., recovery of SO2 catalyst from N2 stripping gas).

[0066] FIG. 17 is an optical micrograph (scale bar 400 microns) of fibers obtained following separation using a four-stage centrifuge and re-slurry system, as a comparative image in Example 1.

[0067] FIG. 18 is an optical micrograph (scale bar 400 microns) of fibers obtained following separation using the FBRS, in Example 1, indicating fiber preservation due to the gentle fiber handling achieved in the filter press.

[0068] FIG. 19 is a graph of the cumulative SO2 removed from the fiber bed versus the cumulative volume of nitrogen stripping gas used, in the first trial of Example 3.

[0069] FIG. 20 is a graph of the cumulative SO2 removed from the fiber bed versus the cumulative volume of nitrogen stripping gas used, in the second trial of Example 3.DETAILED DESCRIPTION OF EMBODIMENTS

[0070] This description will enable one skilled in the art to make and use the invention, and it describes several embodiments, adaptations, variations, alternatives, and uses of the invention. These and other embodiments, features, and advantages of the present invention will become more apparent to those skilled in the art when taken with reference to the following detailed description of the invention in conjunction with any accompanying drawings.

[0071] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. All composition numbers and ranges based on percentages are weight percentages, unless indicated otherwise. All ranges of numbers or conditions are meant to encompass any specific value contained within the range, rounded to any suitable decimal point.

[0072] Unless otherwise indicated, all numbers expressing reaction conditions, stoichiometries, concentrations of components, and so forth used in thespecification and claims are to be understood as being modified in all instances by the term “about.” As used herein, the term “about” means ±20% of the indicated range or value, unless otherwise indicated. Also, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending at least upon a specific analytical technique.

[0073] 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 which means that the named claim elements are essential, but other claim elements may be added and still form a construct within the scope of the claim.

[0074] As used herein, the phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. When the phrase “consists of’ (or variations thereof) appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole. As used herein, the phrase “consisting essentially of’ limits the scope of a claim to the specified elements or method steps, plus those that do not materially affect the basis and novel characteristic(s) of the claimed subject matter.

[0075] With respect to the terms “comprising,” “consisting of,” and “consisting essentially of,” where one of these three terms is used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms, except when used in a Markush group. Thus in some embodiments not otherwise explicitly recited, any instance of “comprising” may be replaced by “consisting of’ or, alternatively, by “consisting essentially of.”

[0076] As used herein, any concentration range, percentage range, ratio range, or integer range is to be understood to include the value of any integer within the recited range and, when appropriate, fractions thereof (such as one tenth of an integer), unless otherwise indicated. Also, any number range recited herein is to be understood to include any integer within the recited range, unless otherwise indicated.

[0077] For purposes of an enabling technical disclosure, various explanations, hypotheses, theories, speculations, assumptions, and so on are disclosed. The present disclosure does not rely on any of these being in fact true. None of the explanations,hypotheses, theories, speculations, or assumptions in this detailed description shall be construed to limit the scope of the disclosure in any way.

[0078] As will be understood by a skilled artisan, in the description of a process herein, the order of process steps may be varied without departing from the scope of the invention defined by the claims. Thus for example when a process is described to include steps A, B, C, and D, it will be understood that, unless otherwise stated, the process may be conducted sequentially (A-B-C-D), or in any other logical sequence (e.g., A-C-B-D, A-B-D-C, B-C-A-D, etc.), which alternative process sequences may not provide all the benefits of the preferred sequence but which nevertheless provide a benefit compared to the prior art. In some embodiments, when steps of a process are disclosed, the process is conducted in sequence, i.e. the first step (often denoted by “(a)”) is conducted before the second step (often denoted by “(b)”), the second step is conducted before the third step (often denoted by “(c)”), and so on. In other embodiments, when steps of a process are disclosed, the process is not conducted in the sequence stated but rather in another sequence.

[0079] This disclosure provides a large number of processes, process steps, process conditions, systems, units, embodiments, and options that are generally useful in biorefineries for converting biomass to sugars, biochemicals, biomaterials, and / or biofuels. It will be recognized by a skilled artisan that the inventive concepts are widely applicable to various biomass-conversion processes, including those employing pretreatment, hydrolysis, pyrolysis, gasification, digestion, fermentation, catalysis, and so on. Many examples of processes will be described herein, with the understanding that there are other embodiments in which fewer than, or more than, the disclosed process steps may be employed for that particular process.

[0080] In many variations, the present invention is predicated on the design and / or operation of a fiber-bed reactive separator. In this disclosure, a “fiber-bed reactive separator” is a physical unit in which both chemical reactions and chemical separations take place, simultaneously or sequentially. When sequentially, reaction can be followed by separation, or separation can be followed by reaction. Sequences can be repeated, e.g. separation-reaction-separation-reaction..., etc. Many chemical reactions and separations are possible, as will be described in this specification.

[0081] In this specification, “fiber” refers to a material that is a solid at a temperature of 25°C and a pressure of 1 bar, and that contains a detectible amount of at least one of cellulose, hemicellulose, or lignin. Other components may be present in a solid fiber, including (but not limited to) modified cellulose, modified hemicellulose, modified lignin, sugar oligomers, sugar monomers (such as glucose, xylose, mannose, arabinose, galactose, or sucrose), starch, proteins, ash, metals, metal oxides, minerals, dirt, fines, acids, bases, salts, phenolic glycosides, sugar alcohols, resins, fatty acids, enzymes, yeast, bacteria, water, and bleaching chemicals (such as sodium hypochlorite, hydrogen peroxide, ozone, chlorine dioxide, or peracetic acid).

[0082] Some variations are premised on the realization that while biorefinery solid / liquid separations are technically challenging, they also present an opportunity. After an efficient solid / liquid separation of pretreated biomass, if the digested fiber is in a concentrated state, reaction operations, mass-transfer operations, and other treatments can be effectively and efficiently performed. Furthermore, by combining reaction and separation in the same unit, chemical reactions can improve separations, and separations can improve the conversion and yield of chemical reactions, while economizing on capital and operating costs.

[0083] The disclosed technology provides processes and systems that utilize a fiber-bed reactive separator (“FBRS”) designed to form a fiber bed for carrying out one or more chemical reactions in addition to separation and washing of pretreated biomass. The disclosed technology enables efficient, low-energy separation and wash operations, in addition to post-separation reaction and mass-transfer steps. The FBRS may be configured with a moving fiber bed or an immobile fiber bed. The FBRS may be implemented using standard commercial equipment such as a diffusion washer, a diffusion extractor, a pressure diffuser, a filter press, a belt filter press, a roll press, a drum filter, or other equipment capable of forming and maintaining a fiber bed. In some illustrated embodiments, a filter press is used as the FBRS, it being understood that the disclosed technology can be utilized across various types of fiber bedforming equipment.

[0084] Considering separation and wash performance, in some variations, the FBRS provides superior product purity by reducing both fine suspended solids in the liquid phase (filtrate) as well as dissolved solids remaining in the fiber bed. Theseparation effectiveness of a conventional centrifuge is partly limited by the specific gravity of the fines. Because lignocellulosic biomass solids are often heterogeneous in composition and density, gravity-based separation methods are inherently limited in their ability to remove these fines. In contrast, the disclosed FBRS achieves fines removal by immobilizing solids during fiber bed formation, thus rendering the specific gravity of the fines irrelevant to separation performance.

[0085] Another benefit of the disclosed technology is a lower wash liquid requirement, minimizing the load on downstream chemical recovery operations, offering further process efficiency gains.

[0086] Another benefit of the disclosed technology is significant electrical power savings. In addition to electrical energy savings in the fiber separation and wash, by reducing the volume of wash liquid needed to achieve an equivalent wash of the fiber, the FBRS also reduces the thermal and electrical energy required for recovery of pretreatment digestion chemicals, when applicable.

[0087] Another benefit of the disclosed technology is that the FBRS is well- suited to preservation of fiber integrity. In applications where maintaining fiber length is critical, such as in the production of nanocellulose, nanofibrils, or other biomaterials, preservation of fiber integrity is important. Furthermore, longer fibers promote a more-porous fiber bed, which in turn enhances the efficiency of not only the separation and washing but also any downstream reaction or mass-transfer operations that rely on fiber bed porosity. The disclosed FBRS can result in less fiber breakage compared to centrifuge and reslurry systems.

[0088] An important aspect of the FBRS is integrated and controlled chemical reactions within the FBRS itself. Because the solids have been separated from the liquids, and are isolated in concentrated form, reactants and catalysts can be efficiently introduced from the liquid phase or the gas phase. Reactants or catalysts in either phase can be applied successively, as required by the reaction scheme, and can be applied at elevated or depressed temperatures to control the reaction temperature. This functional flexibility allows for reaction schemes in the gas phase, the liquid phase, and / or the solid phase (e.g., chemisorption, or reactive desorption) to be efficiently executed with a minimum use of reactants and / or catalysts.

[0089] The FBRS also allows mass-transfer operations to be performed before, after, or between reaction steps, to facilitate the absorption or stripping of molecules to or from the residual liquid phase, respectively, or the adsorption or desorption of molecules to or from the fiber, respectively. These mass-transfer operations can be performed in the FBRS, or in subsequent equipment, or a combination thereof. An example of subsequent equipment for mass transfer is the use of a solids mass-transfer vessel disposed in flow communication with the FBRS. The solids mass-transfer vessel may be a stripping column, an absorption column, an adsorption unit, or an extraction column, for example. An example illustrating a FBRS used for both reaction and mass-transfer operations is the stripping of residual sulfur dioxide from AVAP-pretreated lignocellulosic fiber, which will now be described, without limitation.

[0090] In the AVAP biomass fractionation process, residual sulfur compounds, including sulfite (SO32), bisulfite (HSO3 ), sulfurous acid (H2SO3), and dissolved sulfur dioxide (SO2) remain in the fiber following separation and washing. To remove these compounds, a stripping operation may be executed in the FBRS, wherein the fiber, containing water moisture, is contacted with an inert stripping gas, such as nitrogen (N2). The N2 strips the SO2 from the aqueous phase, within the fiber’s moisture, into the gas phase, thereby producing a loaded stripping gas containing SO2. The flow of stripping gas is maintained until the concentration of SO2 in the loaded stripping gas falls below a predetermined threshold, such as less than 50 parts per million (ppm), at which point the stripping gas flow is temporarily halted. To enhance SO2 removal, an acid is introduced to the fiber bed to produce hydronium in the liquid phase, thereby reducing the pH of the liquid phase and shifting the chemical equilibria among sulfite, bisulfite, sulfurous acid, and dissolved SO2 toward the formation of SO2, as described by the following reaction network:HSO3 + H+H2SO3H2SO3^ SO2(aq) + H2OSO2(aq) SO2(g)The reduced pH favors the formation of dissolved SO2 (aq), which is subsequently desorbed as free SO2 (g) into the stripping gas. Following acid application and equilibrium adjustment, excess acid is expressed from the filter bed, and the flow of stripping gas is resumed. The stripping gas contacts the fiber bed to desorb additional SO2 into the loaded stripping gas, thereby further reducing the residual sulfur content of the fiber. This process involving the formation of hydronium and subsequent shifting of the chemical equilibria among the four species (SO32, HSO3 , H2SO3, and SO2) may be performed prior to the application of any stripping gas, between applications of stripping gas as described above, or in other combinations of reaction and stripping steps. A final wash step can also be applied to recover the SO2.

[0091] In some variations, the present invention provides a method of reactive separation of biomass-derived materials, the method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator,wherein at least one of steps (c) or (e) is conducted.

[0092] In some variations, the present invention provides a method of reactive separation of biomass-derived materials, the method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) applying a pre-separation reaction trigger to the fiber bed to cause a preseparation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the pre-separation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator.

[0093] In some variations, the present invention provides a method of reactive separation of biomass-derived materials, the method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquidphase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator.

[0094] “Biomass” refers to any biologically produced organic matter and includes the mass of living or once-living organisms, including plants and microorganisms. Biomass includes both the above-ground and below-ground tissues of plants — for example, leaves, twigs, branches, boles, as well as roots of trees and rhizomes of grasses. The chemical energy contained in biomass is derived from solar energy using the natural process of photosynthesis. Biomass is effectively stored solar energy. Photosynthesis is the process by which plants take in carbon dioxide and water from their surroundings and, using energy from sunlight, convert them into sugars, starches, cellulose, hemicellulose, and lignin.

[0095] A pretreated biomass stream means that a starting biomass feedstock has undergone some type of chemical and / or mechanical pretreatment, including cleaning, size reduction, steam exposure, hot-water exposure, acid exposure, base exposure, solvent exposure, chemical pulping, mechanical pulping, chemimechanical pulping, or a combination thereof, for example. Generally, a pretreatment chemical may be selected from the group consisting of an acid, a base, a salt, an organic solvent, an inorganic solvent, an ionic liquid, an enzyme, water, and combinations thereof, for example. The pretreatment chemical may be a catalyst or a reactant. In certain embodiments, water is the only pretreatment chemical.

[0096] When an acid is used as a pretreatment chemical, the acid may be a sulfur-containing acid, such as an acid selected from the group consisting of sulfur dioxide, sulfur trioxide, sulfurous acid, sulfuric acid, sulfonic acid, lignosulfonic acid, and combinations thereof. Other acids may be employed. In various embodiments,an acid is selected from the group consisting of sulfuric acid, sulfurous acid, sulfur dioxide, nitric acid, phosphoric acid, hydrochloric acid, acetic acid, formic acid, levulinic acid, maleic acid, lactic acid, and combinations thereof. The acid may be a Bronsted acid or a Lewis acid. An example of a Lewis acid is sulfur dioxide.

[0097] When a base is used as a pretreatment chemical, the base may be selected from the group consisting of ammonia, ammonium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and combinations thereof. The base may be a Bronsted base or a Lewis base.

[0098] In certain embodiments, a pretreatment chemical is an enzyme, separately from any enzyme used downstream, such as in hydrolysis. Pretreatment enzymes may be selected from the group consisting of cellulase, endoglucanase, exoglucanase, beta-glucosidase, hemicellulase, ligninase, and combinations thereof. Ligninase may be used as a pretreatment chemical to remove or modify lignin in the biomass, to improve biomass digestion or to assist in recovery of lignin, for example.

[0099] In certain embodiments, a pretreatment chemical is a solvent for lignin. For example, the solvent for lignin may be selected from the group consisting of a linear alcohol, a branched alcohol, an aromatic alcohol, a ketone, an aldehyde, an ether, a non-oxygenated hydrocarbon, an ionic liquid, and combinations thereof. Exemplary solvents for lignin include methanol, ethanol, ethylene glycol, 1 -propanol, 2-propanol, propanediol, glycerol, 1 -butanol, 2-butanol, isobutanol, butanediol, 1- pentanol, 1 -hexanol, cyclohexanol, and combinations thereof. When the pretreatment utilizes a solvent for lignin, there may or may not also be water in the liquid solution. Also, when the liquid solution includes a solvent for lignin, there may or may not also be a pretreatment catalyst in the liquid solution. For example, in the case of ethanol as a solvent for lignin and sulfur dioxide as a pretreatment catalyst, a liquid solution may contain ethanol, water, and SO2; ethanol and water; water and SO2; ethanol and SO2; water only; or ethanol only.

[0100] In some embodiments, the pretreated biomass stream is a pretreated lignocellulosic biomass stream. The biomass feedstock used herein is typically a lignocellulosic feedstock that contains at least cellulose and lignin. However, the biomass feedstock may vary widely, and need not be a lignocellulosic material, aslong as it contains a detectible amount of at least one of cellulose, hemicellulose, or lignin.

[0101] In some embodiments, the biomass feedstock is a botanical feedstock. Botanical feedstocks may include whole plants, plant herbs, plant roots, plant flowers, plant fruits, plant leaves, plant seeds, plant beans, and combinations thereof. Exemplary botanical feedstocks include com and hemp.

[0102] In various embodiments, the biomass feedstock is selected from softwood chips or sawdust, hardwood chips or sawdust, timber harvesting residues, milled tree branches, milled tree stumps, leaves, bark, paper, cardboard, paper waste, off-spec paper pulp, bamboo, corn stover, wheat straw, rice straw, grass straw, cotton burr, switchgrass, miscanthus, sugarcane bagasse, sugarcane straw, energy cane bagasse, energy cane straw, sugar beet pulp, sunflowers, sorghum, canola, algae, alfalfa, fruit shells, fruit stalks, fruit peels, fruit pits, hemp, vegetable shells, vegetable stalks, vegetable peels, vegetable pits, grape pumice, almond shells, pecan shells, coconut shells, coffee grounds, grass pellets, hay pellets, wood pellets, food waste, commercial waste, municipal solid waste, or a combination thereof. The processes and systems of the invention can accommodate a wide range of feedstocks of various types, sizes, and moisture contents. A person of ordinary skill in the art will appreciate that the biomass feedstock options are virtually unlimited.

[0103] Different biomass feedstocks have different sugar profiles in the cellulose and hemicellulose fractions. For example, in hardwoods and herbaceous feedstocks, the main hemicellulose sugar is the Cs sugar xylose, while in softwoods, both Cs and Ce sugars (particularly mannose) are prevalent in hemicellulose.

[0104] In some embodiments, the biomass feedstock is a herbaceous biomass feedstock. A herbaceous biomass feedstock has little or no woody tissue and typically persists for a single growing season. A herbaceous biomass feedstock may be selected from the group consisting of sugarcane bagasse, sugarcane straw, energy cane bagasse, energy cane straw, com stover, wheat straw, rice straw, grass straw, switchgrass, cotton burr, miscanthus, empty fruit bunches, and combinations thereof, for example. In other embodiments, the biomass feedstock is a non-herbaceous biomass feedstock, such as sawdust or forest waste. A mixture of a herbaceous biomass feedstock and a non-herbaceous biomass feedstock may be used.

[0105] In some embodiments, a biomass feedstock contains cellulose, hemicellulose, and starch. An example is corn fiber, which typically contains about 35% hemicellulose, 18% cellulose, and 20% starch, as well as some lignin, protein, and oil.

[0106] In some embodiments, a biomass feedstock contains cellulose, hemicellulose, and sucrose (a C12 sugar). Examples include whole sugarcane and whole energy cane. These materials may be processed to first mechanically remove sucrose juice, with the remaining material (bagasse) then fed to a process described herein. Alternatively, whole sugarcane or whole energy cane may be processed, with the sucrose — or glucose plus fructose derived from sucrose hydrolysis — optionally being fermented to ethanol or another product, or recovered as a sugar product, for example. When sucrose is fermented, it may be fermented to something different than products made from the cellulose sugars or hemicellulose sugars.

[0107] The biomass feedstock 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 relatively large pieces of material, such as milled wood chips. In some embodiments, the feed material comprises pellets or other agglomerated forms of particles that have been pressed together or otherwise bound, such as with a binder.

[0108] In some embodiments, the biomass feedstock has a maximum average particle dimension selected from about 0.1 millimeters to about 500 millimeters, such as from about 10 millimeters to about 100 millimeters. The maximum average particle dimension is the maximum of average particle length, average particle width, and average particle height. For typical herbaceous biomass feedstocks, the maximum particle dimension is the particle length. A starting herbaceous biomass feedstock is often a long piece of biomass (e.g., a com stalk) that, when milled, can generate high-aspect-ratio particles of biomass. However, the invention is not limited to any specific particle shape. The invention may utilize a flour of lignocellulosic biomass feedstock (e.g., finely milled material) or fine material collected during preprocessing (e.g., com stover pith). In various embodiments, the lignocellulosic biomass feedstock has a maximum average particle dimension of about, at least about,or at most about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 400, or 500 millimeters, including any intervening range.

[0109] In some embodiments, the initial moisture content of the biomass feedstock is about 35 wt% or less H2O, such as about 20 wt% or less H2O. In various embodiments, the initial moisture content of the biomass feedstock is about, at least about, or at most about 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt% (water), including any intervening range. The initial moisture content of the lignocellulosic biomass feedstock may be the natural moisture content of the biomass feedstock as harvested, or may be the result of transportation or storage, for example.

[0110] In some embodiments, the pretreated biomass stream is a slurry containing the solid phase and the liquid phase. With a slurry, there will be excess liquid that contains suspended particles of the solid phase.

[0111] In some embodiments, the pretreated biomass stream is in the form of wet solids in which the liquid phase does not form a free liquid phase within the solid phase. In this specification, a “free” liquid phase means that if the wet solids are subjected to atmospheric, gravity-driven decanting, a liquid phase would naturally drain from the solids after 1 hour at a temperature of 25°C and a pressure of 1 bar.

[0112] The pretreated biomass stream is preferably not a liquid stream with only dissolved solids, but no suspended solids, because such a stream would not form a fiber bed in the fiber-bed reactive separator. Nevertheless, one skilled in the art will recognize that if a process is provided such as liquid stream with only dissolved solids, a pre-evaporation may be performed to increase the solids concentration; and / or additional solids (e.g., recycled solids from downstream operations) may be added in order to achieve a structural slurry or wet solids that may form a fiber bed.

[0113] The pretreated biomass stream may further include one or more process aids, either added during pretreatment or added to the pretreated biomass stream after pretreatment but prior to reactive separation in the fiber-bed reactive separator. In some embodiments, a process aid is added to the pretreated biomass stream, and the mixture is then introduced into the fiber-bed reactive separator. In other embodiments, a process aid is introduced directly into the fiber-bed reactive separator. Exemplary process aids include filter aids, such as diatomaceous earth or silica (which may be derived from biomass ash). Other process aids may includesurfactants, viscosity modifiers, density modifiers, liquid adsorbents, or membrane conditioners, for example. Generally speaking, a process aid functions to improve separation, or is added for some other reason, but is not intentionally a chemical reactant. Nevertheless, depending on choice of process aid and the composition of the fiber bed, and process conditions such as temperature and pH, it is possible that a process aid reacts to some extent.

[0114] In some embodiments, the first biomass-derived material is a cellulose- rich material. In other embodiments, the first biomass-derived material is a ligninrich material. The first biomass-derived material may have substantial quantities of both cellulose and lignin, or substantial quantities of all of cellulose, hemicellulose, and lignin.

[0115] In some embodiments, the solid phase contains from about 25 wt% to about 75 wt% cellulose. In various embodiments, the solid phase contains about, at least about, or at most about 0, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt% cellulose, including any intervening range, on an as-is basis (not a dry basis).

[0116] In some embodiments, the solid phase contains from about 10 wt% to about 50 wt% hemicellulose. In various embodiments, the solid phase contains about, at least about, or at most about 0, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% hemicellulose, including any intervening range, on an as-is basis.

[0117] In some embodiments, the solid phase contains from about 10 wt% to about 50 wt% lignin. In various embodiments, the solid phase contains about, at least about, or at most about 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% lignin, including any intervening range, on an as-is basis.

[0118] In some embodiments, the solid phase contains from about 10 wt% to about 50 wt% water. In various embodiments, the solid phase contains about, at least about, or at most about 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% water, including any intervening range, on an as-is basis.

[0119] In some embodiments, the second biomass-derived material (in the liquid phase) is a hemicellulose-rich material. In other embodiments, the second biomass-derived material is a lignin-rich material.

[0120] In some embodiments, the liquid phase contains from about 1 wt% to about 25 wt% hemicellulose. In various embodiments, the liquid phase contains about, at least about, or at most about 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, or 25 wt% hemicellulose, including any intervening range, on an as-is basis. In these concentration ranges, the hemicellulose is total hemicellulose of any molecular weight (hemicellulose monomers, oligomers, and polymers).

[0121] In some embodiments, the liquid phase contains from about 1 wt% to about 25 wt% lignin. In various embodiments, the liquid phase contains about, at least about, or at most about 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, or 25 wt% lignin, including any intervening range, on an as-is basis. In these concentration ranges, the lignin is total lignin of any molecular weight and regardless of functional groups attached to lignin (e.g., total lignin includes the full weight of sulfonated lignin, ethoxylated lignin, etc.).

[0122] In some embodiments, the liquid phase contains from about 10 wt% to about 90 wt% water. In various embodiments, the liquid phase contains about, at least about, or at most about 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt% water, including any intervening range, on an as-is basis.

[0123] In some embodiments, the liquid phase further comprises a hydrolysis catalyst. The hydrolysis catalyst may be selected from the group consisting of sulfur dioxide, sulfonic acid, lignosulfonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, phosphoric acid, nitric acid, carbonic acid, and combinations thereof. In these embodiments, the liquid phase may contains from about 0.001 wt% to about 20 wt% hydrolysis catalyst(s). In various embodiments, the liquid phase contains about, at least about, or at most about 0, 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%,13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt% hydrolysis catalyst(s), including any intervening range, on an as-is basis. When multiple hydrolysis catalysts are used, these concentrations refer to the total concentration of all hydrolysis catalysts. For example, a liquid phase with 8 wt% SO2 (first hydrolysis catalyst) and 4 wt% H2CO3 (second hydrolysis catalyst), with no other hydrolysis catalysts present, contains 12 wt% total hydrolysis catalysts.

[0124] In some embodiments, the liquid phase further comprises a solvent for lignin. The solvent for lignin may be a Ci-Ce alcohol, such as methanol, ethanol, or a combination thereof. In these embodiments, the liquid phase may contains from about 1 wt% to about 90 wt% solvent for lignin. In various embodiments, the liquid phase contains about, at least about, or at most about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt% solvent, including any intervening range, on an as-is basis. When multiple solvents for lignin are present, these concentrations refer to the total concentration of all solvents for lignin. For example, a liquid phase with 40 wt% ethanol (first solvent) and 10 wt% methanol (second solvent), with no other solvents present, contains 50 wt% total solvents for lignin.

[0125] In certain embodiments, a solvent is present in the liquid phase, but the solvent is not a solvent for lignin. These embodiments may be applicable when there is no lignin in the pretreated biomass stream, or very little lignin. Or, these embodiments may be applicable when a solvent for another species is desirable. For example, in the case of pretreated pine softwood, a solvent for terpenes (e.g., a- pinene) may be included in the liquid phase. An exemplary solvent for terpenes is cyclohexane.

[0126] In some embodiments, the liquid phase further comprises a sulfonic acid, a lignosulfonic acid, a Ci-Ce organic acid, a fatty acid, a Ci-Ce aldehyde, a Ci- Ce ketone, a Ci-Ce polyol, or a combination thereof. In these embodiments, the liquid phase may contains from about 0.001 wt% to about 25 wt% of any one of a sulfonic acid, a lignosulfonic acid, a Ci-Ce organic acid, a fatty acid, a Ci-Ce aldehyde, a Ci- Ce ketone, or a Ci-Ce polyol. In various embodiments, the liquid phase contains about, at least about, or at most about 0, 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.05 wt%,0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt% (on an as-is basis), including any intervening range, of any one of a sulfonic acid, a lignosulfonic acid, a Ci-C6organic acid, a fatty acid, a Ci-Ce aldehyde, a Ci-Ce ketone, or a Ci-Ce polyol.

[0127] In some embodiments, the fiber bed is an immobilized fiber bed. In other embodiments, the fiber bed is a moving fiber bed. In certain embodiments, the fiber bed is an immobilized fiber bed for a first amount of time, and a moving fiber bed for a second amount of time, which may be sequential or interspersed with the first amount of time.

[0128] Prior to separation of the liquid phase from the solid phase, the fiber bed may have various concentrations of solids, such as from about 5 wt% solids to about 75 wt%, for example. In various embodiments, prior to separation of the liquid phase from the solid phase, the fiber bed may have a solids concentrations of about, at least about, or at most about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75%, including any intervening range. Even at just 5 wt% solids, some pretreated biomass streams (such as those containing nanocellulose) form structural slurries capable of forming a fiber bed.

[0129] In some embodiments, the fiber-bed reactive separator is a filter press. The filter press may be a squeeze-plate filter press containing a plurality of immobilized fiber beds spaced apart by plates and / or membranes, for example. A squeeze-plate filter press enables efficient separation of the solid phase from the liquid phase. It has been discovered that because the fiber is immobilized in the filter press, successive countercurrent washes can be executed with a minimum amount of wash liquid, in these embodiments. The use of the squeeze function and evacuation gas (e.g., N2) allows for the production of a fiber bed with 50 wt% or greater total solids, even for a relatively closed fiber bed typically produced by a pliable pretreated fiber. Additionally, the power consumption of a squeeze-plate filter press is substantially lower than the power requirements of horizontal decanters.

[0130] In certain embodiments, a filter press is configured with plates having inflatable diaphragms. The plates may be membrane squeeze-filter plates. Some embodiments utilize a cross-wash functionality as well as a cross-blow functionality.There may be a wash from the lower right of a plate, across the fiber bed, to the upper left of the adjacent plate. The same can be done from the lower left to the upper right. Working in reverse, gas (e.g., N2) can be injected in the upper left, and removed on the lower right — or the upper right and removed on the lower left. This cross- wash / cross-blow functionality provides good wash and promotes the desired chemical reactions. In certain embodiments, a cross wash is used, while a cross blow is not used. In certain embodiments, a cross wash is not used, while a cross blow is used. In certain preferred embodiments, both a cross wash and a cross blow are used.

[0131] In some embodiments, the fiber-bed reactive separator is a belt filter press. A belt filter press may also be referred to as a belt filter or a belt press filter. A belt filter press can be conceptually similar to a filter press, but the belt transports the fiber bed in continuously or semi-continuously. The fiber bed is thus considered a moving fiber bed, even if the bed is periodically stationary (when the belt is not moving).

[0132] A belt filter press may be configured to separate the liquid phase from the solid phase by pressing the pretreated biomass stream to force the liquid through a permeable medium. Drainage and mechanical pressure may be used sequentially to remove liquid. There may be multiple recirculating belts, with two porous belts combining to compress the material and squeeze liquid from it. A belt filter press may contain a second high-pressure zone comprising a series of rollers through which the two belts pass with solids retained between them. The rollers in this high-pressure zone may apply tensioning to the belts, exerting both shear and compressive forces on the material which releases more liquid.

[0133] In some embodiments, the fiber-bed reactive separator is a diffusion washer that utilizes a moving fiber bed. The diffusion washer may be operated at atmospheric pressure, or at elevated pressure, in which case it may be referred to as a pressure diffuser (disclosed below). A diffusion washer is a common piece of pulping equipment that uses a combination of filtration and diffusion to separate pretreated solids from liquid. The diffusion washer preferably operates on a counterflow principle, where solids moves upward and are washed by liquid flowing downwards through a series of baffles. Diffusion washers are known for gentle and efficient displacement washing, which is beneficial for handling small fiber particles withoutcausing fiber loss or fiber-bed sealing. Even when operating at atmospheric pressure, the diffusion washer is preferably enclosed from the environment.

[0134] In diffusion washers, solids fines typically do not flow through the perforated screens because of how the washing process is designed. Diffusion washers operate at low pressure gradients across the fiber bed and the screen. Unlike vacuum drum washers, which pull liquid (and sometimes fines) forcefully (via mechanical force) through the screen, diffusion washers rely on gentle, uniform displacement of liquid. Slow, controlled movement keeps the fiber bed stable and minimizes the forces that could drive fine particles through the screen. The fine fibers naturally form a tight, cohesive fiber bed during the washing process. The fiber bed acts as a natural filter — once a thin layer of fibers forms over the screen, the layer traps additional fibers and fines, preventing them from reaching the screen perforations. The screens in diffusion washers are preferably designed with small, closely spaced perforations, optimized for low flow velocities at the surface. This design reduces the chance that even very small particles (fines) will be carried through the holes. Diffusion washers are good at washing through dense fiber mats without causing sealing, where wash liquid just flows over the surface instead of through the fiber bed. In a diffusion washer, the primary flow is preferably horizontal across the fiber bed rather than directly perpendicular to the screen. This sideways flow further reduces the likelihood of fibers being pushed through the screen openings.

[0135] Diffusion washers are preferred for the fiber-bed reactive separator, in some embodiments, due to the combination of continuous operation, gentle flow dynamics, superior fiber-bed formation, and optimized screen design that prevents solid fines from being lost to the liquid-rich material. In a diffusion washer, the fiber bed is formed and maintained under low pressure and low-shear conditions. The fiber bed is typically uniform, dense, and relatively undisturbed during washing. Because the liquid flows gently across and through the fiber bed — mainly by displacement rather than suction — the fiber structure remains intact, minimizing fiber bed compaction or fiber loss. The fiber bed is relatively thick and stable, acting as an effective filter to trap fines while allowing efficient liquid exchange. Its formation is preferably optimized to maximize surface area for diffusion without causingchanneling or fiber-bed sealing. In contrast, in a drum washer, the fiber mat forms by vacuum suction onto a rotating drum’s surface. The vacuum pulls liquid and solids against the screen or wire mesh, quickly building up a fiber mat. However, because suction is applied, the fiber mat is often more porous, less uniform, and less dense compared to a diffusion washer. Fine fibers are more prone to being pulled through the screen during mat formation or washing. Additionally, the fiber mat can experience greater mechanical stress during rotation, liquid application, and removal. This can lead to variations in mat thickness, potential for fiber loss, and uneven washing if not properly controlled, when using a drum washer.

[0136] In certain embodiments, the fiber-bed reactive separator is a pressure diffuser that utilizes a moving fiber bed. Most of the advantages of diffusion washers, discussed above, also apply to pressure diffusers. Pressure diffusers have the added advantage of being able to operate at high pressures and high temperatures, which can be highly desirable for chemical reactions taking place in the FBRS, and for controlling volatile chemicals such as pretreatment solvents or wash liquids.Generally, a pressure diffuser comprises an elongated, generally vertical vessel which mounts an elongated annular screen for vertical movement within the vessel. Pretreated biomass under pressure flows into one end of the vessel and into the annular space between the screen and the exterior vessel wall, and through an outlet at the other end of the vessel. As the pressurized, moving fiber bed traverses the height of the vessel, displaced liquid phase is introduced into the annular chamber by a plurality of vertically spaced header assemblies. The displaced liquid phase flows generally radially inwardly through the fiber bed and through the screen into the interior of the vessel that is equipped with a liquid outlet. The screen is moved concurrently with the fiber bed and is returned quickly to clean the screen by combined wiping and back-flushing. Different diameters of the upper and lower ends of the screen create filtrate compression during screen movement, thereby forcing the liquid through the screen holes to back-flush the screen.

[0137] In preferred embodiments, the fiber-bed reactive separator is not one or more disc centrifuges or decanter centrifuges. In a disc centrifuge or a decanter centrifuge, there is movement (spinning) of fiber with high centrifugal forces causing separation of liquid from solid based on a density difference. The fiber-bed reactiveseparator typically requires significantly lower power consumption compared to a centrifuges or decanter system, and is better able to handle fine particles of pretreated biomass, among other advantages. Nevertheless, a biorefinery may utilize one or more centrifuges or a decanters upstream or downstream of the disclosed fiber-bed reactive separator and the disclosed method.

[0138] In certain less-preferred embodiments, the fiber-bed reactive separator is a vacuum drum washer. In preferred embodiments, the fiber-bed reactive separator is not a vacuum drum washer, which is believed to be technically unsuitable for certain types of pretreated biomass (e.g., when fiber length is small). A typical vacuum drum washer includes a drum, a tank, a plane distribution valve, a washing device, a peel pulp device, net-washing equipment, and a screw conveyor. The drum rotates in a tank containing pulp. As a result of vacuum suction, the liquid in the pulp is pumped out of the filtrate flow path and the distribution valve. The pulp is adsorbed on the outer surface of the drum body and peeled off by the doctor blade to achieve the suction, stripping, and exhausting processes of the pulp. As the drum turns a circle, filtration, washing, and stripping of pulp are completed.

[0139] In some embodiments, the method further comprises, following step(b), mechanically squeezing the fiber bed to enhance separation of the liquid phase from the solid phase.

[0140] Mechanical squeezing may be conducted between steps (b) and (c). Alternatively, or additionally, mechanical squeezing may be conducted during step(c). Alternatively, or additionally, mechanical squeezing may be conducted between steps (c) and (d). Alternatively, or additionally, mechanical squeezing may be conducted during step (d). Alternatively, or additionally, mechanical squeezing may be conducted after step (d), such as during step (e) or during step (f).

[0141] In some embodiments, mechanical squeezing is accomplished using a squeeze liquid that applies pressure directly to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze liquid that enters a membrane, wherein the membrane applies pressure to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze gas that applies pressure directly to the fiber bed. In some embodiments, mechanical squeezing is accomplished using a squeeze gas that enters a membrane, wherein the membraneapplies pressure to the fiber bed. In some embodiments, mechanical squeezing is accomplished by physical force applied between an outer plate and the fiber bed. In some embodiments, mechanical squeezing is accomplished by physical force applied between a membrane and the fiber bed.

[0142] In some embodiments, the method further comprises, following step (b), blowing a blow gas through the fiber bed, which may enhance separation of the liquid phase from the solid phase, or which may be used to strip a species out of the fiber bed (from either the solid or liquid phase) and into the vapor phase. The blowing may be conducted between steps (b) and (c). Alternatively, or additionally, the blowing is conducted during step (c). Alternatively, or additionally, the blowing is conducted between steps (c) and (d). Alternatively, or additionally, the blowing is conducted during step (d). Alternatively, or additionally, the blowing is conducted after step (d), such as during or after step (e). The blow gas may be referred to as a stripping gas when the intent is to strip one or more species (such as SO2) out of the fiber bed. The blow gas may pass through the fiber bed in cross flow.

[0143] When a blow gas is used, the blow gas may be selected from the group consisting of air, N2, CO2, Ar (argon), He (helium), and combinations thereof, for example. In some embodiments, the blow gas is selected from the group consisting of N2, CO2, Ar, He, and combinations thereof. In some embodiments, the blow gas is not air. In some embodiments, the blow gas contains no greater than 1 mol% O2. In some embodiments, the blow gas contains no greater than 0.1 mol% O2. In certain embodiments, the blow gas contains no greater than 0.01 mol% O2. The blow gas may contain no detectible O2. A low-oxygen or no-oxygen blow gas is preferred when the liquid phase and / or the solid phase of the fiber bed is flammable.

[0144] In some embodiments, the method further comprises, following step (b), washing the fiber bed using a wash fluid, which may enhance separation of the liquid phase from the solid phase. The washing may be conducted between steps (b) and (c). Alternatively, or additionally, the washing may be conducted during step (c). Alternatively, or additionally, the washing may be conducted between steps (c) and (d). Alternatively, or additionally, the washing may be conducted during step (d). Alternatively, or additionally, the washing may be conducted after step (d), such as during or after step (e).

[0145] The wash fluid may pass through a core of the fiber bed.Alternatively, or additionally, the wash fluid may pass through the fiber bed in cross flow. As stated earlier, in cross flow, a wash is performed from the lower right of a plate, across the fiber bed, to the upper left of the adjacent plate. Alternatively, or additionally, a wash may be performed from the lower left of a plate, across the fiber bed, to the upper right of the adjacent plate.

[0146] In some embodiments, the wash fluid is a wash liquid. The wash liquid may be selected from the group consisting of water, a Ci-Ce alcohol, a Ci-Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a fatty acid, a sulfonic acid, a lignosulfonic acid, and combinations thereof. In certain embodiments, the wash liquid is water. In certain embodiments, the wash liquid is a mixture of water and ethanol. The mixture may contain, or consist essentially of, from about 5 wt% to about 95 wt% water, and from about 95 wt% to about 5 wt% ethanol.

[0147] In some embodiments, the wash fluid is a wash vapor. The wash vapor may be selected from the group consisting of steam, nitrogen, argon, helium, carbon dioxide, a Ci-Ce alcohol, a Ci-Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a sulfonic acid, a lignosulfonic acid, and combinations thereof.

[0148] Multiple washing steps may be employed, wherein each of the multiple washing steps uses an independently selected wash fluid. In these embodiments, one or more steps may use a wash liquid, while one or more steps may use a wash vapor. For example, alternating wash liquid-wash vapor washes may be used. Or, a series of wash liquids may be utilized, followed by one or more wash vapors.

[0149] In some embodiments in which the fiber-bed reactive separator contains a plurality of immobilized fiber beds spaced apart by plates and / or membranes, the wash fluid cocurrently passes through the plurality of immobilized fiber beds, relative to flow direction of the liquid phase. In other embodiments, the wash fluid countercurrently passes through the plurality of immobilized fiber beds, relative to flow direction of the liquid phase. All other things equal, countercurrent washing is usually more effective than cocurrent washing.

[0150] In some embodiments, step (c) is conducted while step (e) is not conducted. In some embodiments, step (e) is conducted while step (c) is not conducted. In certain embodiments, both of steps (c) and (e) are conducted in themethod. In certain less-preferred embodiments of the disclosure (such as during startup, shutdown, or transient plant operations), neither steps (c) nor (e) are conducted; in these embodiments, a fiber-bed reactive separator is still utilized, and a fiber bed is still generated, but no chemical reactions are carried out.

[0151] Reaction triggers will now be described in detail. It will be understood that a reaction trigger is a pre-separation reaction trigger when applied during step (c), or a post-separation reaction trigger when applied during step (e). When both steps (c) and (e) are conducted, there are distinct reaction triggers that may be the same or different types of reaction triggers.

[0152] In some embodiments, a reaction trigger comprises a change in pH within the fiber bed. When a pH reduction is desired, the change in pH may be accomplished by adding an inorganic acid (e.g., phosphoric acid), an organic acid (e.g., a phosphonic acid), or a combination thereof, to the fiber bed, for example. When a pH increase is desired, the change in pH may be accomplished by adding an inorganic base (e.g., ammonia), an organic base (e.g., ethylamine), or a combination thereof, to the fiber bed, for example.

[0153] The change in pH may be a pH change of the liquid phase. In these embodiments, the hydrogen-ion (H+) concentration is directly adjusted in the liquid phase. Alternatively, or additionally, the change in pH may be a pH change associated with the solid phase. In these embodiments, molecules within the solid phase are chemically adjusted, such as at functional groups (e.g., -OH or -COOH groups), to cause uptake of H+from the liquid, or release of H+into the solution. Conventionally, pH applies only to liquids, not solids. The pH of the solution may be measured to determine the pH change associated with the solid phase.

[0154] In some embodiments, the change in pH causes pH to be adjusted to about 6 or less, about 5 or less, about 4 or less, about 3 or less, or about 2 or less. In certain embodiments, the change in pH causes pH to be adjusted to a pH selected from about 1.0 to about 2.0. In certain embodiments, the change in pH causes pH to be adjusted to a pH selected from about 0.5 to about 1.5. In various embodiments, the change in pH causes pH to be adjusted to a value of about, at least about, or at most about 6.5, 6.0, 5.5, 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2,1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, or 0.0, including any intervening range.

[0155] In some embodiments, the change in pH causes pH to be adjusted to about 8 or more, about 9 or more, about 10 or more, about 11 or more, or about 12 or more. In various embodiments, the change in pH causes pH to be adjusted to a value of about, at least about, or at most about 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, or 14.0, including any intervening range.

[0156] In some embodiments, the liquid phase further comprises sulfur dioxide and / or a compound derived therefrom, and the reaction trigger comprises a reduction in pH within the fiber bed. In these embodiments, the reduction in pH shifts a sulfite-species chemical equilibrium toward a higher concentration of free SO2 in the liquid phase. The compound derived from SO2 may be a sulfonic acid (e.g., an a- hydroxyalkane sulfonic acid), a lignosulfonic acid (e.g., 3-(2-hydroxy-3- methoxyphenyl)-2-[2-methoxy-4-(3-sulfopropyl)phenoxy]propane-l-sulfonic acid), a sulfite salt (e.g., calcium sulfite), a bisulfite salt (e.g., ammonium bisulfite), or a combination thereof, for example. The method may further comprise separating free SO2 from the liquid phase, while the liquid phase is still present in the fiber bed, when step (c) is conducted. Alternatively, or additionally, the method may further comprise separating free SO2 from the liquid phase, during step (d). Alternatively, or additionally, the method may further comprise separating free SO2 from the residual liquid still contained within the solid-rich material, during step (e). Alternatively, or additionally, the method may further comprise separating free SO2 from the liquidrich material after it is directed to an output liquid stream. In those embodiments, free SO2 can be separated from the output liquid stream in another unit that is different than the fiber-bed reactive separator.

[0157] In some embodiments, the method further comprises, following step (b), blowing a blow gas through the fiber bed. Free SO2 may be captured in the blow gas. Optionally, some or all of the captured SO2 may be recovered and reused. For example, when the blow gas is N2, SO2 may be separated from N2 using zeolite membranes (e.g., SSZ-13 high-silica aluminosilicates), metal-organic frameworks (e.g., copper-based pyrazines), pressure-swing adsorption, or cryogenic distillation.

[0158] In some embodiments, the method further comprises, following step (b), washing the fiber bed using a wash fluid. Free SO2 may be captured in the wash fluid (e.g., a wash vapor such as steam). Optionally, some or all of the captured SO2 may be recovered and reused. For example, when the wash fluid is steam, SO2 may be separated from steam using steam stripping to remove SO2 from the mixture, or using absorption with an alkaline-based solution to neutralize and remove SO2.

[0159] In some embodiments, the reaction trigger comprises a change in temperature of the fiber bed. The change in temperature may cause the temperature of the fiber bed to be from about 50°C to about 200°C, for example. In various embodiments, the reaction trigger comprises a change in temperature of the fiber bed to a temperature of about, at least about, or at most about 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, including any intervening range.

[0160] In certain embodiments, the reaction trigger involves an indirect trigger that in turn causes a direct trigger. For example, a chemical reactant as an indirect trigger could cause temperature to rise (e.g., due to a reaction exotherm), which then directly triggers the desired chemical reaction within the fiber bed. In those cases, the desired chemical reaction does not necessarily use the chemical reactant, which may have been consumed in the initial reaction but not necessarily in the primary triggered reaction.

[0161] In some embodiments, the reaction trigger comprises a change in pressure within the fiber bed. The change in pressure may cause the pressure in the fiber bed to be from about 0.1 bar to about 20 bar, for example. In this specification, the unit “bar” is always gauge pressure (bar = barg), not absolute pressure (bara). In certain embodiments, vacuum (<1 bar) is applied to the fiber bed. In various embodiments, the reaction trigger comprises a change in pressure in the fiber bed to a pressure of about, at least about, or at most about 0.1 bar, 0.2 bar, 0.3 bar, 0.4 bar, 0.5 bar, 0.6 bar, 0.7 bar, 0.8 bar, 0.9 bar, 1 bar, 1.5 bar, 2 bar, 2.5 bar, 3 bar, 4 bar, 5 bar, 6 bar, 7 bar, 8 bar, 9 bar, 10 bar, 11 bar, 12 bar, 13 bar, 14 bar, 15 bar, 16 bar, 17 bar, 18 bar, 19 bar, or 20 bar, including any intervening range.

[0162] In some embodiments, the reaction trigger comprises addition of a chemical reactant to the fiber bed. The chemical reactant may be added viadisplacement, absorption, adsorption, chemisorption, or combinations thereof. In some embodiments, the chemical reactant is an inorganic acid. In some embodiments, the chemical reactant is an organic acid. Multiple chemical reactants may be added for the reaction trigger, or multiple reaction triggers taking place simultaneously or sequentially.

[0163] In some embodiments, the chemical reactant is selected from the group consisting of SO2, CO2, CO, H2, H2O, CH4, NH3, HNO3, NO, NO2, H2SO4, H3PO4, HC1, CI2, CIO2, O2, O3, H2O2, and combinations thereof. An exemplary reaction using SO2 is sulfonation of lignin. An exemplary reaction using CO2 is formation of carbonic acid. An exemplary reaction using CO is carbonylation of cellulose. An exemplary reaction using H2 is hydrogenation of a double bond. An exemplary reaction using H2O is hydrolysis of cellulose, hemicellulose, or starch. An exemplary reaction using CH4 is deoxygenation of lignin. An exemplary reaction using NH3 is lignin amination. An exemplary reaction using HNO3, NO, and / or NO2 is lignin depolymerization. An exemplary reaction using H2SO4, H3PO4, and / or HC1 is acid- catalyzed hydrolysis of sugar polymers into oligomers and / or monomers. An exemplary reaction using Ch is cellulose chlorination, which can be used to functionalize cellulose for subsequent chemical transformations to incorporate other functionalities. An exemplary reaction using CIO2 is lignin oxidation and potentially lignin molecular-weight reduction. An exemplary reaction using O2 is sugar oxidation. An exemplary reaction using O3 is lignin ozonolysis and potentially lignin molecular-weight reduction. An exemplary reaction using H2O2 is oxidative lignin depolymerization.

[0164] In certain embodiments, the chemical reactant is sulfur dioxide, SO2. The SO2 may react with lignin that is, or is contained in, the first biomass-derived material, thereby increasing sulfur content of the lignin. Alternatively, or additionally, the SO2 may react with lignin that is, or is contained in, the second biomass-derived material, thereby increasing sulfur content of that lignin. When the sulfur content of lignin is increased, the result may be a lignosulfonic acid, lignosulfonate ions, or a lignosulfonate salt, depending on pH and the concentration of cations (e.g., Ca2+). An exemplary sulfonated lignin is 3-(2-hydroxy-3- methoxyphenyl)-2-[2-methoxy-4-(3-sulfopropyl)phenoxy]propane-l -sulfonic acid,which is C20H26O10S2 that stoichiometrically contains approximately 13 wt% sulfur. However, it will be understood that a lower degree of lignin sulfonation may result from the reaction with SO2. It is also possible to achieve a highly sulfonated lignin, with higher than 13 wt% sulfur. In some embodiments, the sulfonated lignin contains from about 1 wt% sulfur to about 15 wt% sulfur. In various embodiments, the sulfonated lignin contains about, at least about, or at most about 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, or 20 wt%, including any intervening range.

[0165] In some embodiments, cellulose contained in the solid phase reacts with the chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to glucose and / or other cellulose sugars. “Enzymatic digestibility” refers to the reactivity of the cellulose with cellulase enzymes, to depolymerize the cellulose into oligomer and monomer sugars (principally glucose).

[0166] In some embodiments, hemicellulose contained in the solid phase reacts with the chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to xylose and / or other hemicellulose sugars. “Enzymatic digestibility” with respect to hemicellulose refers to the reactivity of the hemicellulose with hemicellulase enzymes, to depolymerize the hemicellulose into oligomer and monomer sugars (principally xylose or, in the case of softwoods, mannose). In these or other embodiments, hemicellulose contained in the liquid phase may react with the chemical reactant to generate hemicellulose sugars. In certain embodiments, hemicellulose contained in both the solid and liquid phases reacts with the chemical reactant to generate hemicellulose sugars.

[0167] In some embodiments, the solid-rich material recovered in step (f) has a solids concentration of at least 50 wt% solids. In certain embodiments, the solidrich material recovered in step (f) has a solids concentration of at least 75 wt% solids. In various embodiments, the solid-rich material recovered in step (f) has a solids concentration of about, at least about, or at most about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt%, including any intervening range.

[0168] In various embodiments, the liquid-rich material recovered from the output liquid stream has a solids concentration of about, at least about, or at mostabout 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, including any intervening range.

[0169] In some embodiments, the method further comprises recovering a pretreatment chemical (e.g., H2SO4 or SO2) from the liquid-rich material, and reusing the pretreatment chemical in pretreatment of fresh biomass.

[0170] In some embodiments, the method further comprises further processing of the solid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, cellulose, nanocellulose, pulp, paper, hemicellulose, lignin, or a combination thereof.

[0171] In some embodiments, the method further comprises further processing of the liquid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, hemicellulose, lignin, or a combination thereof.

[0172] Preferably, further processing of the liquid-rich material does not include an evaporation step prior to fermentation and / or catalysis. These embodiments are very beneficial from an economic viewpoint, since evaporation is energy-intensive. Consequently, these embodiments are also very beneficial for reducing the overall biorefinery carbon intensity.

[0173] In some embodiments, the method is conducted in batch. In a batch method, a pretreated biomass stream is obtained. The pretreated biomass stream may itself have been made in a batch or continuous process. The pretreated biomass stream is introduced to the fiber-bed reactive separator, forming a fiber bed. There will then be a batch time associated with the reactive separation. During the batch time, the fiber bed may remain stationary (immobilized fiber bed), or the fiber bed may move, such as in a loop or other movement (moving fiber bed). Also during the batch time, at a pre-specified time or at an arbitrary time, a reaction trigger is applied to cause a chemical reaction in situ within the fiber bed. Following the desired chemical reaction, at least some of the liquid phase is separated from the solid phase, generating a solid-rich material and a liquid-rich material. Once the solid-rich material and a liquid-rich material are collected, the batch is considered complete.

[0174] In some versions of batch methods, a semi-batch method is utilized, in which either pretreated biomass is added to the fiber-bed reactive separator at multiple times, and / or a solid-rich material and a liquid-rich material are collected at multipletimes, during the overall batch time. In a semi-batch method, the intervals between multiple times for either feed input or product output may be regular or irregular, and may be based on process control feedback, for example.

[0175] In some embodiments, the method is conducted continuously. In a fully continuous method, a pretreated biomass stream is continuously provided. The pretreated biomass stream itself is preferably produced in a continuous pretreatment process. The pretreated biomass stream is continuously introduced to the fiber-bed reactive separator, forming a fiber bed. There will be a residence time associated with the reactive separation. During the residence time, the fiber bed may remain stationary (as a temporarily immobilized fiber bed) for a period of time, following formation of the bed and prior to bed ejection. Alternatively, the fiber bed may be continuously formed and moved, such as across a belt, or through a pressure diffuser. A reaction trigger is continuously applied to cause a chemical reaction in situ within the immobilized or moving fiber bed. The desired chemical reaction occurs continuously within the fiber bed. At least some of the liquid phase is continuously separated from the solid phase, generating a solid-rich material and a liquid-rich material that are each recovered.

[0176] In some versions of continuous methods, a semi-continuous method is utilized. In a semi-continuous method, a pretreated biomass stream is continuously or periodically introduced to the fiber-bed reactive separator, forming a fiber bed. There will be a residence time associated with the reactive separation. During the residence time, the fiber bed may remain stationary (as a temporarily immobilized fiber bed) for a period of time, following formation of the bed and prior to bed ejection. Alternatively, the fiber bed may be continuously or intermittently formed and moved, such as across a belt, or through a pressure diffuser. A reaction trigger is continuously or intermittently applied to cause a chemical reaction in situ within the immobilized or moving fiber bed. Eithin the fiber bed, the desired chemical reaction occurs continuously or intermittently, depending on when the reaction trigger is applied. At least some of the liquid phase is continuously or intermittently separated from the solid phase, generating a solid-rich material and a liquid-rich material that are each recovered. In a semi-continuous method, at least one step is performed non- continuously. Multiple steps, but less than all steps, may be performed non-continuously, in a semi-continuous method. Hybrid methods are a mixture of batch, semi-batch, semi-continuous, and continuous methods.

[0177] In some variations of the disclosed technology, the method of reactive separation is used in the AVAP® process. The AVAP process, developed over the past two decades, is commonly owned with the assignee of the present patent application. In a typical version, the AVAP process utilizes a biomass pretreatment (fractionation) with a solution of SO2, alcohol (e.g., ethanol), and water. The AVAP process requires a post-pretreatment solid / liquid separation and wash to separate the digested fiber (largely cellulose) from the pretreatment mixture, which is largely hemicellulose, lignosulfonic acid, alcohol-soluble lignin, and digestion chemicals SO2, alcohol, and water. This separation is a major contributor to both the capital and operating costs of the AVAP process, as digested fiber must be processed to ensure (1) the purity of the hydrolyzed-cellulose Ce saccharide stream, (2) efficient separation of SO2 from the solids and liquids, and (3) the recovery of the SO2, alcohol, and water for reuse in pretreatment. The separation is complicated by the fact that the AVAP digested fibers are typically small and pliable. Screw presses are problematic in the separation, since the pliable fibers do not form a good plug at the discharge of the screw press. Consequently, excessive fines are lost in the filtrate. Because the particles are small and pliable, the solids form a closed fiber bed, making both drum filters impractical.

[0178] In certain variations, the present invention provides a method of reactive separation of biomass-derived materials made using AVAP pretreatment, the method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the pretreated biomass stream is AVAP -pretreated biomass, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquidphase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator, wherein at least one of steps (c) or (e) is conducted.

[0179] The disclosed fiber-bed reactive separator may be applied in many distinct biorefinery processes, including (but not limited to) solid / liquid separations, fiber washing, post-hydrolysis separation, stillage separation, nanocellulose postproduction dewatering, and nanocellulose thickening.

[0180] The disclosed fiber-bed reactive separator may be used when producing a wide variety of biorefinery products, including (but not limited to) pretreated biomass as a fuel substrate (e.g., as pellets), sugars, fermentation products such as ethanol, derivatives of fermentation products (e.g., sustainable aviation fuel), lignin, depolymerized lignin, cellulose, hemicellulose, nanocellulose crystals, nanocellulose fibrils, biogas from anaerobic digestion of pretreated biomass, syngas from gasification of pretreated biomass, heat, steam, electricity, and combinations thereof.

[0181] The method may include mechanically treating the solid-rich material to generate cellulose nanofibrils and / or cellulose nanocrystals. Exemplary processes and apparatus to convert nanocellulose precursor pulp into cellulose nanofibrils and / or cellulose nanocrystals are described in commonly owned U.S. Patent No. 9,187,865, issued on November 17, 2015, which is hereby incorporated by reference herein.

[0182] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(g) recovering the solid-rich material from the fiber-bed reactive separator, wherein at least one of steps (f) or (f) is conducted.

[0183] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises cellulose, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator;(h) hydrolyzing (with enzymes or an acid catalyst) the cellulose in the solidrich material to generate glucose; and(i) recovering the glucose as a sugar product, wherein at least one of steps (d) or (f) is conducted.

[0184] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase, and wherein the second biomass-derived material contains one or more sugars;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator; and(h) recovering a sugar product directly from the liquid-rich material, wherein at least one of steps (d) or (f) is conducted.

[0185] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises cellulose, and wherein the liquid phase comprises water and hemicellulose that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause apost-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator;(h) hydrolyzing (with enzymes or an acid catalyst) the hemicellulose in the liquid-rich material to generate a hemicellulose sugar; and(i) recovering the hemicellulose sugar as a sugar product, wherein at least one of steps (d) or (f) is conducted.

[0186] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises cellulose, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator;(h) mechanically refining the solid-rich material to generate nanocellulose; and(i) recovering the nanocellulose as a nanocellulose product, wherein at least one of steps (d) or (f) is conducted.

[0187] In some biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises lignin, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator; and(h) recovering the lignin from the solid-rich material as a lignin product, wherein at least one of steps (d) or (f) is conducted.

[0188] In certain biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises cellulose, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator;(h) hydrolyzing (with enzymes or an acid catalyst) the cellulose in the solidrich material to generate glucose; and(i) fermenting the glucose to ethanol, wherein at least one of steps (d) or (f) is conducted.

[0189] In certain biorefinery variations, a method of reactive separation of biomass-derived materials comprises:(a) providing a starting biomass stream;(b) pretreating the starting biomass stream in a pretreatment reactor, thereby generating a pretreated biomass stream, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the solid phase comprises cellulose, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(c) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(d) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(e) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(f) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material;(g) recovering the solid-rich material from the fiber-bed reactive separator;(h) hydrolyzing (with enzymes or an acid catalyst) the cellulose in the solidrich material to generate glucose;(i) fermenting the glucose to ethanol;(j) dehydrating the ethanol to ethylene;(k) oligomerizing the ethylene to hydrocarbon oligomers; and(l) processing the hydrocarbon oligomers, using separations, catalysis, and hydrotreating, to form aviation fuel, which preferably qualifies as sustainable aviation fuel according to ASTM D7566, wherein at least one of steps (d) or (f) is conducted.

[0190] Certain variations of the disclosure are premised on the recognition that a fiber-bed reactive separation may be useful to achieve better solid / liquid separation compared to conventional centrifuges or decanters, even in the absence of chemical reactions.

[0191] In some embodiments, a method of separation (which may or may not be reactive separation) of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, andwherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to the fiber bed to cause a pre-separation chemical reaction of at least one component within the liquid phase and / or at least one component within the solid phase, wherein the preseparation chemical reaction takes place in situ within the fiber bed;(d) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to the solid-rich material, while the solid-rich material is still contained in the fiber bed, to cause a post-separation chemical reaction of at least one component within the solid-rich material; and(f) recovering the solid-rich material from the fiber-bed reactive separator.

[0192] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a fiber-bed reactive separator, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the fiber-bed reactive separator.

[0193] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a filter press, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the filter press.

[0194] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a diffusion washer, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the diffusion washer.

[0195] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a pressure diffuser, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the pressure diffuser.

[0196] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a belt press, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the roll press.

[0197] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a belt press, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the roll press.

[0198] Some embodiments of the disclosure are premised on the realization that a diffusion washer or a pressure diffuser can work surprisingly well for separating AVAP-pretreated biomass, which is different than kraft pulp or sulfite pulp. In contrast to kraft pulping or sulfite pulping, AVAP-pretreated biomass is made from a pretreatment that uses SO2, water, and a solvent for lignin, such as ethanol. The use of SO2, rather than salts thereof (e.g., calcium sulfite), causes different pretreatment chemistry and therefore different fiber characteristics.

[0199] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the pretreated biomass stream is AVAP-pretreated biomass, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a diffusion washer, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-rich material remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the diffusion washer.

[0200] In some embodiments, a method of separation of biomass-derived materials comprises:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein the pretreated biomass stream is AVAP-pretreated biomass, wherein the solid phase comprises a first biomass-derived material, and wherein the liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in the liquid phase;(b) introducing the pretreated biomass stream to a pressure diffuser, wherein the pretreated biomass stream forms a fiber bed;(c) separating at least a portion of the liquid phase from the solid phase, to generate a solid-rich material and a liquid-rich material, wherein the solid-richmaterial remains in the fiber bed, and wherein the liquid-rich material is directed to an output liquid stream; and(d) recovering the solid-rich material from the pressure diffuser.

[0201] Some variations of the invention will now be further described in reference to the accompanying drawings, without limiting the scope of the invention as defined by the claims. FIGS. 1 to 16 are simplified block-flow diagrams depicting the method and system of various embodiments. In these drawings, dotted lines denote optional streams and units.

[0202] FIG. 1 is an exemplary block-flow diagram of the processing that takes place in a fiber-bed reactive separator (FBRS), in some embodiments. Dotted lines denote optional steps and streams. Digested biomass (the pretreated biomass stream) is fed to the primary separation zone, forming a fiber bed. Digestion liquor (liquid phase) is separated from the fiber bed; the fiber remains in the bed. A series of optional washes is then performed, starting with wash liquid A (e.g., ethanol) that generates a loaded wash liquid, containing pretreatment chemicals, impurities, inhibitors, etc. The number of washes may be 0, 1, 2, 3, 4, to more (total number of washes is N in FIG. 1). Wash liquid B (e.g., water) is fed to the N* wash stage, generating a N* wash filtrate. The N* wash filtrate is fed to wash stage N - 1, which is depicted in FIG. 1 as being the second wash stage (N = 3). If N > 3, the N* wash filtrate is fed to wash N - 1, etc. The second wash filtrate is fed to the first wash stage. Following the N* wash, a blow gas (e.g., air) may be blown through the fiber bed to decrease residual liquid content, generating a wash liquid B blowdown. When blowing through the fiber bed, the blow gas may absorb wash liquid B as well as residual liquid still contained within the fiber. The fiber bed then undergoes a selected reaction that is triggered by adding a reactant or catalyst, as depicted in FIG.1, or by adjusting pH, temperature, pressure, or another condition within the fiber bed. Because the reaction follows the primary separation, it is a post-separation reaction, although it precedes the separation that takes place in the mass-transfer step. Finally, a stripping gas (e.g., nitrogen) may be used in a mass-transfer step to cause the release of a selected species (e.g., sulfur dioxide) from the fiber, into a loaded stripping gas (e.g., N2 / SO2). The fiber is recovered as a solid-rich material that may be furtherprocessed. Note that the fiber-bed reactive separator in FIG. 1 may be configured as a vertical, horizontal, or slanted unit, and may be batch or continuous.

[0203] FIG. 2 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 2 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include wash liquids and stripping gas. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 2, N = 4 (four wash stages). The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid and loaded stripping gas form secondary outputs, which both may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, and stripped components back to a biomass pretreatment unit, for example. In FIG. 2, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may also be a reaction trigger, since feeding a temperature- controlled wash liquid A to the fiber bed will cause a change in the bed temperature. The reaction trigger may then cause a selected reaction to occur within the fiber bed. In certain embodiments of the disclosure, there is no reaction trigger and no reaction.

[0204] FIG. 3 is a block-flow diagram of a method of, and system configured for, non-reactive separation of biomass-derived materials in a comparative process that employs a sequence of centrifuges. In FIG. 3, the primary input to the first centrifuge is digested biomass, and the primary output is a washed fiber.

[0205] FIG. 4 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 4 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include reactant or catalyst, wash liquids, and stripping gas. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 4, N = 4 (four wash stages). In FIG. 4, the reaction triggeris addition of a reactant or catalyst. In FIG. 4, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled wash liquid A to the fiber bed, while the reactant or catalyst is added to the wash liquid A before it is fed to the fiber bed. The reaction trigger(s) cause(s) a selected reaction to occur within the fiber bed. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid and loaded stripping gas form secondary outputs, which both may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, and stripped components back to a biomass pretreatment unit, for example. Unused reactant (if any), and the catalyst if used, also are secondary outputs that can be recovered and reused in principle. FIG. 4 depicts the introduction of a reactant or catalyst to the fiber isolated in a FBRS in a once- through configuration.

[0206] FIG. 5 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 5 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include reactant or catalyst, wash liquids, and stripping gas. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 5, N = 4 (four wash stages). In FIG. 5, the reaction trigger is addition of a reactant or catalyst. In FIG. 5, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled wash liquid A to the fiber bed, while the reactant or catalyst is added to the wash liquid B before it is fed to the fiber bed. The reaction trigger causes a selected reaction to occur within the fiber bed. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid and loaded stripping gas form secondaryoutputs, which both may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, and stripped components back to a biomass pretreatment unit, for example. Unused reactant or catalyst are recovered from the fiber bed and reused by combining with wash liquid B. That is, FIG. 5 depicts the introduction of a reactant or catalyst to the fiber in a recirculating liquid configuration.

[0207] FIG. 6 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 6 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include catalyst and / or reactant, wash liquids, and stripping gas (which may also function as a carrier gas for a gas-phase catalyst or reactant). Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 6, N = 4 (four wash stages). In FIG. 6, the reaction trigger is addition of a reactant and / or catalyst. In FIG. 6, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled wash liquid A to the fiber bed, while the reactant (e.g., SO2) and / or catalyst (e.g., methanesulfonic acid) are injected directly into the fiber bed. The reaction trigger causes a selected reaction (e.g., lignin sulfonation) to occur within the fiber bed. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid and loaded stripping gas form secondary outputs, which both may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, and stripped components back to a biomass pretreatment unit, for example. Unused reactant and / or catalyst are recovered from the fiber bed and may be reused in principle. FIG.6 depicts the introduction of a gas-phase reactant or catalyst to the fiber in an FBRS in a once-through configuration.

[0208] FIG. 7 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 7 is a fiber-bed reactive separator, which may be apressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include catalyst and / or reactant, wash liquids, and stripping gas. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 7, N = 4 (four wash stages). In FIG. 7, the reaction trigger is addition of a reactant and / or catalyst. In FIG. 7, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled wash liquid A to the fiber bed, while the reactant and / or are injected directly into the fiber bed. The reaction trigger causes a selected reaction to occur within the fiber bed. In addition, a pressure changer is disposed in flow communication with the FBRS, to increase or decrease the pressure in the fiber bed. The pressure changer may be another reaction trigger, or may be used to assist stripping or catalyst / reactant injection and / or recovery, for example. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid and loaded stripping gas form secondary outputs, which both may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, and stripped components back to a biomass pretreatment unit, for example. Unused reactant and / or catalyst are recovered from the fiber bed and may be reused in principle. FIG. 7 depicts the introduction of a gas-phase reactant or catalyst to the fiber in an FBRS in a once- through configuration.

[0209] FIG. 8 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 8 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. The primary input to the FBRS is digested biomass (the pretreated biomass stream); secondary inputs include reactant or catalyst, wash liquids, stripping gas, absorber feed gas, adsorption feed gas, and desorption gas. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 8, N = 4 (four wash stages). In FIG. 8, the reaction trigger is addition of a reactant or catalyst. InFIG. 8, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled wash liquid A to the fiber bed, while the reactant or catalyst is added to the wash liquid B before it is fed to the fiber bed. The reaction trigger causes a selected reaction to occur within the fiber bed. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid, loaded stripping gas, absorber lean gas, adsorption lean gas, and desorbed gas form secondary outputs, which may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, stripped components, absorber feed gas, adsorption feed gas, and / or desorption gas for optional reuse in the FBRS. As shown in FIG. 8, stripping gas, absorber lean gas, adsorption lean gas, and desorbed gas may be recovered from the solid-rich stream (fiber), or from the liquidrich stream (digestion liquor), or from both of these streams. In FIG. 8, unused reactant or catalyst are recovered from the fiber bed and reused by combining with wash liquid B, in a recirculating liquid configuration.

[0210] FIG. 9 is an exemplary block-flow diagram of a method of, and system configured for, reactive separation of biomass-derived materials, in some embodiments. The FBRS in FIG. 9 is a fiber-bed reactive separator, which may be a pressure diffuser, a filter press, or another suitable apparatus that forms a fiber bed. In addition, a solids mass-transfer vessel is disposed in flow communication with the FBRS. The primary input to the FBRS is digested biomass (the pretreated biomass stream). Secondary inputs include reactant or catalyst, wash liquids, stripping gas, absorber feed gas, adsorption feed gas, and desorption gas, all of which may be fed to the FBRS, or to the solids mass-transfer vessel, or to both the FBRS and the solids mass-transfer vessel. Exemplary operation of the FBRS can be understood in connection with FIG. 1, discussed above. In FIG. 9, N = 4 (four wash stages). In FIG. 9, the reaction trigger is addition of a reactant or catalyst. In FIG. 9, there is a temperature adjustment of wash liquid A, such as an increased temperature for a more effective wash. The temperature adjustment may be another reaction trigger. The temperature adjustment is accomplished by feeding a temperature-controlled washliquid A to the fiber bed, while the reactant or catalyst is added to the wash liquid B before it is fed to the fiber bed. The reaction trigger causes a selected reaction to occur within the fiber bed. The primary outputs from the FBRS are the fiber (the solid-rich material) and the digestion liquor (the liquid-rich material), which both may be further processed in a wide variety of ways. Loaded wash liquid, loaded stripping gas, absorber lean gas, adsorption lean gas, and desorbed gas form secondary outputs, which may be processed for recycling wash liquids, components of wash filtrates, the stripping gas, stripped components, absorber feed gas, adsorption feed gas, and / or desorption gas for optional reuse in the FBRS. As shown in FIG. 9, stripping gas, absorber lean gas, adsorption lean gas, and desorbed gas may be recovered directly from the FBRS, or from the solids mass-transfer vessel, or from the digestion liquor, or from any combination (including all) of these locations. In FIG. 9, unused reactant or catalyst are recovered from the fiber bed and reused by combining with wash liquid B.

[0211] FIG. 10 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 10 depicts (as denoted by arrows, »>. . .) the use of the FBRS in one or more method steps that input digested biomass and output digestion liquor (liquid-rich stream), with the fiber remaining in the fiber bed of the FBRS. The drawing of FIG.10 is a snapshot in time, or a subset of total method time, corresponding to a step of primary solid / liquid separation.

[0212] FIG. 11 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 11 depicts (as denoted by arrows) the use of the FBRS in one or more method steps that input stripping gas to the FBRS that already contains a fiber bed. During these method steps, a loaded stripping gas is generated. The drawing of FIG.11 is a snapshot in time, or a subset of total method time, corresponding to a step of stripping. Typically, the step(s) of FIG. 11 follow the step(s) of FIG. 10, although in certain embodiments some stripping is carried our prior to solid / liquid separation.

[0213] FIG. 12 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 12 depicts (as denoted by arrows) the use of the FBRS in one or moremethod steps that input wash liquid A, which is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed. During these method steps, a loaded wash liquid is generated. The drawing of FIG. 12 is a snapshot in time, or a subset of total method time, corresponding to a step of initial washing. The step(s) of FIG. 12 follow the step(s) of FIG. 10.

[0214] FIG. 13 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 13 depicts (as denoted by arrows) the use of the FBRS in one or more method steps that input wash liquid A, which is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed once. The wash filtrate generated from the washing in FIG. 13 proceeds to the second wash filtrate tank. The drawing of FIG. 13 is a snapshot in time, or a subset of total method time, corresponding to a second washing stage. The step(s) of FIG. 13 follow the step(s) of FIG. 10 and the step(s) of FIG. 12.

[0215] FIG. 14 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 14 depicts (as denoted by arrows) the use of the FBRS in one or more method steps that input wash liquid B, which is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed three times. The wash filtrate generated from the washing in FIG. 14 proceeds to the fourth wash filtrate tank. The drawing of FIG. 14 is a snapshot in time, or a subset of total method time, corresponding to a fourth washing stage. The step(s) of FIG. 14 follow the step(s) of FIG. 10, FIG. 12, and FIG. 13.

[0216] FIG. 15 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 5. FIG. 15 depicts (as denoted by arrows) the use of the FBRS in one or more method steps that input reactant or catalyst, combined with wash liquid B, which is temperature-adjusted for purposes of the reaction trigger, to the FBRS that already contains a fiber bed and has already been washed multiple times. FIG. 15 depicts recycle and reuse of reactant or catalyst. The drawing of FIG. 15 is a snapshot in time, or a subset of total method time, corresponding to recovery and reuse of reactantor catalyst. The step(s) of FIG. 15 follow the step(s) of FIG. 10, and may be before or after the steps of FIG. 12, FIG. 13, and FIG. 14.

[0217] FIG. 16 is an exemplary block-flow diagram of a method of reactive separation of biomass-derived materials, in some embodiments in connection with FIG. 6. FIG. 16 depicts (as denoted by arrows) the use of the FBRS in one or more method steps that input a catalyst and / or a reactant to the FBRS that already contains a fiber bed. After use, the catalyst and / or reactant are recovered from the FBRS (e.g., recovery of SO2 catalyst from N2 stripping gas). The drawing of FIG. 16 is a snapshot in time, or a subset of total method time, corresponding to use and recovery of catalyst or reactant. The step(s) of FIG. 16 follow the step(s) of FIG. 10, and may be before or after the steps of FIG. 12, FIG. 13, FIG. 14, and FIG. 15.

[0218] In some variations, the present invention provides a system configured for carrying out any of the disclosed methods.

[0219] In some embodiments, a system configured for reactive separation of biomass-derived materials comprises a fiber-bed reactive separator with a system input and a system output, wherein the system input is configured to feed a pretreated biomass stream to the fiber-bed reactive separator, wherein the pretreated biomass stream contains a solid phase and a liquid phase, wherein the fiber-bed reactive separator is designed to form a fiber bed from the pretreated biomass stream, and wherein the fiber-bed reactive separator is designed to carry out a chemical reaction in situ within the fiber bed upon application of a reaction trigger.

[0220] In preferred systems, the fiber-bed reactive separator is selected from the group consisting of diffusion washers, pressure diffusers, filter presses, belt filter presses, roll presses, and combinations thereof, adapted to carry out a selected chemical reaction in situ within the fiber bed upon application of a reaction trigger, such as pH or temperature.

[0221] It should be noted that in the block-flow diagrams (FIGS. 1-16), specific unit operations may be omitted in some embodiments and in these or other embodiments, other unit operations not explicitly shown may be included. In each of FIGS. 1 to 16, dotted lines explicitly denote optional streams and units. The invention is not limited to what is shown, or not shown, in the exemplary drawings.

[0222] Various valves, pumps, meters, sensors, sample ports, etc. are not shown in the block-flow diagrams of FIGS. 1-16. Additionally, multiple pieces of equipment (rather than single pieces of equipment), either in series or in parallel, may be utilized for any unit operations. Also, solid, liquid, and vapor streams produced or existing within the method and system may be independently recycled, passed to subsequent steps, or removed / purged at any point. In FIGS. 1-16, a portion or all of an intermediate stream may be recovered as a co-product, if desired. Or, a product may be passed to another unit for further processing, in which case the product becomes an intermediate rather than final product.

[0223] Material can generally be conveyed into and out of the FBRS by pumps, screws, and the like. Material can be conveyed mechanically by physical force, pressure-driven flow, pneumatically driven flow, centrifugal flow, gravitational flow, fluidized flow, or some other known means of moving material.

[0224] The mode of operation for a FBRS can be continuous, semi- continuous, batch, or any combination or variation of these.

[0225] Various flow patterns can be desired or observed in the FBRS. With chemical reactions and simultaneous separations involving multiple phases in multiple reactor zones, the fluid dynamics can be quite complex.

[0226] A system may include a subsystem for adjusting temperature, pressure, and / or residence time within the FBRS. A subsystem may be configured to vary parameters, such as over a prescribed protocol, or in response to measured variables. For example, an unintended change in FBRS pressure may be compensated by a change in FBRS temperature and / or residence time. As another example, temperature may be maintained constant (isothermal operation) or pressure may be maintained constant (isobaric operation). The subsystem may utilize well-known control logic principles, such as feedback control and feedforward control. Control logic may incorporate results from previous experiments or production campaigns.

[0227] In some embodiments, a reaction probe is disposed in operable communication with a reaction zone in the FBRS. Such a reaction gas probe can be useful to extract vapors, liquids, or solids and analyze them, in order to determine extent of reaction, pH, temperature, or other process monitoring. Then, based on the measurement, the process can be controlled or adjusted in any number of ways, suchas by adjusting processing rate, temperature, pressure, agitation, additives, and so on. Process adjustments based on the measurements, if deemed necessary or desirable, may be made using well-known principles of process control (feedback, feedforward, proportional-integral-derivative logic, etc.).

[0228] For example, SO2 concentration in a vapor phase within the FBRS may be measured using a gas probe to extract a sample, which is then analyzed using a suitable technique, such as gas chromatography, GC; mass spectroscopy, MS; GC- MS, or Fourier-Transform Infrared Spectroscopy, FTIR.

[0229] Safety considerations may be applied to the methods and systems. A unit may include protective devices (e.g., a safety release valve) that automatically activate when the temperature or pressure exceeds a maximum value, for example. Practical safety-related design may be built into the system as well. Those skilled in the art will understand how to design safe units.

[0230] In some embodiments, the system input is in flow communication with a storage tank or other storage unit that received a pretreated biomass stream, such as from another site, which may be a co-located adjacent site.

[0231] The system may be in flow communication with a biomass-processing unit that generates the pretreated biomass stream at the same site as the FBRS. The biomass-processing unit may be a biomass digestor, for example. When the biomassprocessing unit is a biomass digestor, the method may further comprise operating the biomass digestor to digest a starting biomass feedstock to generated the pretreated biomass stream.

[0232] The biomass digestor may utilize a digestor reaction solution. The digestor reaction solution may consist of steam and / or liquid hot water. The digestor reaction solution may comprise a pretreatment chemical. The pretreatment chemical may be selected from the group consisting of an acid, a base, a salt, an organic solvent, an inorganic solvent, an ionic liquid, an active protein, a microorganism, and combinations thereof, for example. An active protein is typically an enzyme, such as cellulase enzymes, but may be fragments of enzymes that are chemically active for pretreatment. The pretreatment chemical may be a catalyst or a reactant.

[0233] In some embodiments, the biomass digestor is operated at a digestor temperature selected from about 100°C to about 220°C. In various embodiments, thebiomass digestor temperature is about, at least about, or at most about 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, or 220°C, including any intervening ranges.

[0234] In some embodiments, the biomass digestor is operated at a digestor pressure selected from about 1 bar to about 25 bar. In various embodiments, the biomass digestor pressure is about, at least about, or at most about 1 bar, 1.5 bar, 2 bar, 2.5 bar, 3 bar, 4 bar, 5 bar, 6 bar, 7 bar, 8 bar, 9 bar, 10 bar, 15 bar, 20 bar, or 25 bar, including any intervening range.

[0235] In some embodiments, the solid-rich material is fed to a mechanical refiner. Mechanically refining of the solid-rich material may employ milling, grinding, beating, sonicating, or any other means to reduce particle size. Mechanical refiners include, without limitation, Valley beaters, single-disk refiners, double-disk refiners, conical refiners (including both wide angle and narrow angle), cylindrical refiners, homogenizers, microfluidizers, and other similar milling or grinding apparatus. See, for example, Smook, Handbook for Pulp & Paper Technologists, Tappi Press, 1992, which is incorporated by reference.

[0236] In certain embodiments, the mechanical refiner is selected from the group consisting of a hot-blow refiner, a hot-stock refiner, a blow-line refiner, a disk refiner, a conical refiner, a cylindrical refiner, an in-line defibrator, a homogenizer, and combinations thereof (noting that these industry terms are not mutually exclusive to each other). Other mechanical refiners may be employed, and chemical refining aids (e.g., fatty acids) may be introduced, such as to adjust viscosity, density, lubricity, etc.

[0237] In some embodiments, the solid-rich material is processed to hydrolyze the cellulose and / or the hemicellulose to monomeric and / or oligomeric sugars, using enzymes or a hydrolysis catalyst. The monomeric and / or oligomeric sugars may be recovered as a sugar product. Alternatively, or additionally, the monomeric and / or oligomeric sugars may be fermented to a fermentation product. Alternatively, or additionally, the monomeric and / or oligomeric sugars may be catalytically converted to a catalysis product.

[0238] In some embodiments, the solid-rich material is mechanically, chemically, and / or enzymatically processed to convert cellulose into nanocellulose. For example, see U.S. Patent No. 9,187,865, issued on November 17, 2015; U.S. Patent No. 9,322,133, issued on April 26, 2016; U.S. Patent No. 10,093,748, issued on October 9, 2018; U.S. Patent No. 10,906,994, issued on February 2, 2021; and U.S. Patent No. 11,932,706, issued in March 19, 2024, which are each hereby incorporated by reference herein for nanocellulose production processes that may be used in some embodiments.

[0239] In some embodiments, the solid-rich material is gasified to generate syngas. The syngas may be converted to electricity via integrated gasification combined cycle, to hydrocarbons via Fischer-Tropsch synthesis, to alcohols such as methanol via catalytic conversion, or to other downstream chemicals.

[0240] Many types of biomass digesters are possible. The biomass digester may be horizontal, vertical, or inclined. The biomass digester may or may not have any internal agitator or means for agitation. The biomass digester may be fixed in place, or be allowed to rotate (e.g., about its axial or radial dimensions). The biomass digester may be operated in upflow or downflow mode, relative to the solids or the solid-liquid mixture. When there is excess liquid, the biomass digester may be operated either cocurrently or countercurrently (solid flow versus liquid flow). The biomass digester may be operated continuously, semi-continuously, in batch, or some combination or hybrid thereof. The flow pattern in the biomass digester may be plug flow, well-mixed, or any other flow pattern. The biomass digester may be heated internally or externally, such as by steam, hot oil, etc. Generally, the principles of chemical-reactor engineering may be applied to digester design and operation.

[0241] The system may further comprise a fermenter configured to ferment monomeric and / or oligomeric sugars to a fermentation product. Alternatively, or additionally, the system may further comprise a catalysis reactor configured to catalyze monomeric and / or oligomeric sugars to a catalysis product. The type of catalyst may vary widely, including homogeneous catalysts and heterogeneous catalysts, e.g. metal-coated aluminosilicates.

[0242] The monomeric and / or oligomeric sugars may be generated in an enzymatic hydrolysis unit that is part of the system. In some embodiments, enzymesintroduced or present in the enzymatic hydrolysis unit may include not only cellulases but also hemicellulases. In certain embodiments, enzymes introduced or present in the enzymatic hydrolysis unit include endoglucanases and exoglucanases.

[0243] Enzymatic hydrolysis may be conducted at a solid concentration from about 10 wt% to about 30 wt%, such as about 12 wt%, 15 wt%, 17 wt%, 20 wt%, 22 wt%, 25 wt%, or 28 wt%, for example.

[0244] Effective enzymatic hydrolysis conditions may include a maximum temperature of 75°C or less, preferably 65°C or less. In some embodiments, the effective hydrolysis conditions include a hydrolysis temperature of about 30°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or 70°C. These are average temperatures within the hydrolysis reactor.

[0245] Effective enzymatic hydrolysis conditions may include a pH from about 4 to about 6, such as a pH of about, at least about, or at most about 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, or 6.0, including any intervening ranges.

[0246] When hydrolysis is catalyzed with an acid catalyst rather than enzymes, an effective hydrolysis temperature may be from about 90°C to about 150°C, and an effective hydrolysis pH may be from about 0.5 to about 2, for example.

[0247] When hydrolysis is catalyzed with an alkaline catalyst rather than enzymes, an effective hydrolysis temperature may be from about 90°C to about 150°C, and an effective hydrolysis pH may be from about 10 to about 12, for example.

[0248] Effective hydrolysis conditions may include a pressure of about atmospheric pressure, such as a pressure from about 0.5 bar to about 2 bar, or from about 0.8 bar to about 1.2 bar.

[0249] The enzymatic hydrolysis unit may include a single stage configured for cellulose liquefaction and saccharification, wherein the single stage includes one or more tanks or vessels. Alternatively, the enzymatic hydrolysis unit may include two stages configured for cellulose liquefaction followed by saccharification, wherein each stage includes one or more tanks or vessels.

[0250] When the hydrolysis process employs enzymes, these enzymes will typically contain cellulases (endoglucanases and exoglucanases) and hemicellulases.The cellulases here may include P-glucosidases that convert cellooligosaccharides and disaccharide cellobiose into glucose. There are enzymes that can attack hemicelluloses, such as (but not limited to) glucoronide, acetylesterase, xylanase, arabinase, P-xylosidase, galactomannase, and glucomannase.

[0251] In some embodiments, a hydrolysis reactor is configured to cause at least some liquefaction as a result of enzymatic action on the cellulose-rich solids. “Liquefaction” means partial hydrolysis of cellulose and / or hemicellulose to form sugar oligomers that dissolve into solution, but not total hydrolysis of cellulose or hemicellulose to sugar monomers (saccharification).

[0252] Various fractions of cellulose may be hydrolyzed during liquefaction. In some embodiments, the fraction of cellulose hydrolyzed during liquefaction may be from about 5% to about 90%, such as about 10% to about 75%, e.g. about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%.

[0253] Various fractions of hemicellulose may be hydrolyzed during liquefaction. In some embodiments, the fraction of hemicellulose hydrolyzed during liquefaction may be from about 5% to about 90%, such as about 10% to about 75%, e.g. about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%.

[0254] In certain embodiments, there is no separate liquefaction tank or reactor; liquefaction and hydrolysis may occur in the same vessel.

[0255] A “liquefaction-focused blend of enzymes” means a mixture of enzymes that includes at least one enzyme capable of hydrolyzing cellulose and / or hemicellulose to form soluble oligomers. In some embodiments, a liquefaction- focused blend of enzymes includes both endoglucanases and exoglucanases. Endoglucanases are cellulases that attack low-crystallinity regions in the cellulose fibers by endoaction, creating free chain-ends. Exoglucanases or cellobiohydrolases are cellulases that hydrolyze the 1,4-glycocidyl linkages in cellobiose.

[0256] Various cellulase enzymes may be utilized in the liquefaction-focused blend of enzymes, such as one or more enzymes disclosed in Verardi et al., “Hydrolysis of Lignocellulosic Biomass: Current Status of Processes and Technologies and Future Perspectives,” Bioethanol, InTech (2012), which is incorporated by reference herein.

[0257] Some embodiments employ thermotolerant enzymes obtained from thermophilic microorganisms. The thermophilic microorganisms can be grouped in thermophiles (growth up to 60°C), extreme thermophiles (65-80°C) and hyperthermophiles (85-110°C). The unique stability of the enzymes produced by these microorganisms at elevated temperatures and pressures, and extreme pH, makes them valuable for processes at harsh conditions. Also, thermophilic enzymes have an increased resistance to many denaturing conditions such as the use of detergents which can be an efficient means to obviate the irreversible adsorption of cellulases on the substrates. Furthermore, the utilization of high operation temperatures, which cause a decrease in viscosity and an increase in the diffusion coefficients of substrates, have a significant influence on the cellulose solubilization. Most thermophilic cellulases do not show inhibition at high level of reaction products (e.g. cellobiose and glucose). As consequence, higher reaction rates and higher process yields are expected. The high process temperature also reduces contamination. See Table 6, “Thermostable cellulases” in Verardi et al., cited above, for exemplary thermotolerant enzymes that may be used in the liquefaction-focused blend of enzymes, or in other embodiments.

[0258] In some embodiments, an enzyme is selected such that at a high temperature, the enzyme is able to catalyze liquefaction (partial hydrolysis) but not saccharification (total hydrolysis). When the temperature is reduced, the same enzyme is able to catalyze saccharification to produce glucose monomer.

[0259] Some embodiments employ two or more enzymatic hydrolysis units. The first enzymatic hydrolysis unit may include a single stage configured for cellulose liquefaction and saccharification, wherein the single stage includes one or more tanks or vessels. Alternatively, the first enzymatic hydrolysis unit may include two stages configured for cellulose liquefaction followed by saccharification, wherein each stage includes one or more tanks or vessels.

[0260] The second enzymatic hydrolysis unit may include a single stage configured for cellulose liquefaction and saccharification, wherein the single stage includes one or more tanks or vessels. Alternatively, the second enzymatic hydrolysis unit may include two stages configured for cellulose liquefaction followed by saccharification, wherein each stage includes one or more tanks or vessels. In certainembodiments, the process further comprises recycling at least some material treated in the second enzymatic hydrolysis unit, for solid / liquid separation, for example.

[0261] Enzymes introduced or present in the second enzymatic hydrolysis unit may likewise include cellulases and hemicellulases. In some embodiments, enzymes introduced or present in the second enzymatic hydrolysis unit include endoglucanases and exoglucanases.

[0262] The hydrolysis reactor may be configured in one or more stages or vessels. In some embodiments, a hydrolysis reactor is a system of two, three, or more physical vessels which are configured to carry out liquefaction or hydrolysis of sugar oligomers. For example, in certain embodiments, a liquefaction tank is followed by a hydrolysis tank, which is then followed by another tank for extended hydrolysis. Enzymes may be added to any one or more of these vessels, and enzyme recycling may be employed.

[0263] In other embodiments, a single physical hydrolysis reactor is utilized, which reactor contains a plurality of zones, such as a liquefaction zone, a first hydrolysis zone, and a second hydrolysis zone. The zones may be stationary or moving, and the reactor may be a continuous plug-flow reactor, a continuous stirred reactor, a batch reactor, a semi-batch reactor, or any combination of these, including arbitrary flow patterns of solid and liquid phases.

[0264] A mechanical refiner may be included before liquefaction, between the liquefaction tank and hydrolysis tank, and / or between the hydrolysis tank and the extended hydrolysis tank. Alternatively or additionally, a mechanical refiner may be included elsewhere in the process. Enzymes may be introduced directly into any of the refiners, if desired.

[0265] In some embodiments, enzymes are introduced directly to the mechanical refiner. In these or other embodiments, the enzymes are introduced to the digested stream, upstream of the mechanical refiner. The enzymes may include cellulases (e.g., endoglucanases and exoglucanases) and hemicellulases.

[0266] Generally speaking, enzymatic hydrolysis should be optimized for the biomass type, the capital cost of tanks versus solids content, energy integration with the rest of the plant, and enzyme cost versus sugar yield. For each commercial implementation, one skilled in the art may carry out a design of experiments incooperation with an enzyme supplier, or in conjunction with on-site enzyme production. In some embodiments, a process disclosed herein is retrofitted to an existing impregnation system, an existing digestor, an existing refiner, an existing hydrolysis reactor, and / or an existing fermentation system.

[0267] Some embodiments further include removing a solid stream containing lignin prior to fermentation of the fermentable sugars. In these or other embodiments, the process may further include removing a solid stream containing lignin following fermentation of the fermentable sugars. The lignin may be combusted for energy production or used for other purposes, such as conversion to carbon products or aromatic molecules.

[0268] In some embodiments, the solid-rich material is enzymatically hydrolyzed to convert the cellulose and hemicellulose (contained in the solid-rich material) to sugars. Additionally, the liquid-rich material may be subjected to enzymatic hydrolysis to convert hemicellulose oligomers into monomeric sugars, such as xylose.

[0269] Enzymes generally may be applied to conduct enzymatic hydrolysis (e.g., cellulose and / or hemicellulose conversion to monomeric sugars), enzymatic isomerization (e.g., glucose conversion to fructose), or other enzymatic reactions.

[0270] Optionally, sugars are processed via sugar separation into a monomer- enriched stream, which may be beneficial for fermentation. Sugar separation may be accomplished using membrane separation, for example. Monomeric and / or oligomeric sugars include, but are not limited to, glucose, xylose, arabinose, mannose, galactose, fructose, sucrose, and oligomers thereof.

[0271] In some embodiments, monomeric and / or oligomeric sugars are fermented to a fermentation product, such as (but not limited to) ethanol, n-butanol, isobutanol, butanediols (e.g., 1,4-butanediol), succinic acid, lactic acid, or a combination thereof.

[0272] In some embodiments, the monomeric and / or oligomeric sugars are recovered as a sugar product, or multiple sugar products.

[0273] In some embodiments, monomeric and / or oligomeric sugars are catalytically converted to a biofuel or a biochemical, such as (but not limited to)ethanol, ethylene, propylene, butenes, butadienes, bionaphtha, gasoline, jet fuel, diesel fuel, or a combination thereof.

[0274] The solid-rich stream from step (f) may be processed to convert the cellulose into nanocellulose as a biomaterial. The nanocellulose may include cellulose nanofibrils, cellulose nanocrystals, or a combination thereof.

[0275] The solid-rich stream from step (f) may be alternatively, or additionally, processed in many other ways to produce one or more sugars, biofuels, biochemicals, or biomaterials. For example, the solid-rich stream may be subjected to pyrolysis, hydropyrolysis, hydrotreating, gasification, steam reforming, combustion, anaerobic digestion, or a combination thereof, or any other biorefinery downstream process that benefits from the reactive separation taking place in the FBRS.

[0276] As used herein, “pyrolysis” is the thermal decomposition of a carbonaceous material. In pyrolysis, less oxygen is present than is required for complete combustion of the material, such as at most about 10%, 1%, 0.1%, or 0.01% of the oxygen (O2 molar basis) that is required for complete combustion. In some embodiments, pyrolysis is performed in the absence of oxygen.

[0277] As used herein, “hydropyrolysis” is the thermal decomposition of a carbonaceous material in the presence of hydrogen. In hydropyrolysis, less oxygen is present than is required for complete combustion of the material, such as at most about 10%, 1%, 0.1%, or 0.01% of the oxygen (O2 molar basis) that is required for complete combustion. In some embodiments, hydropyrolysis is performed in the absence of oxygen.

[0278] “Hydrotreating” refers to exposure to hydrogen for purposes of adding hydrogen to a molecule (e.g., hydration of an olefin using H2), removing a component from a molecule (e.g., sulfur removal via S + H2 — > H2S), or a combination thereof.

[0279] In the case of hydropyrolysis and hydrotreating, the H2 is preferably renewable hydrogen. As used herein, “renewable hydrogen” is determined by correlating the2H / 1H isotopic ratio with the renewability of the starting feedstock. The2H / 1H isotopic ratio correlates with renewability of the hydrogen, with higher2H / 1H isotopic ratios indicating a greater renewable hydrogen content.

[0280] As used herein, “gasification” refers to the conversion of biomass at high temperatures (typically >700°C), without combustion, by controlling the amountof oxygen and / or steam present in the reaction. When the gasification employs only steam and no oxygen, the reactions may be referred to as steam reforming.

[0281] As used herein, “anaerobic digestion” refers to the conversion of the organic material in biomass by bacteria, in the absence of oxygen, to create methane- rich biogas.

[0282] There is extraordinary commercial interest in sustainable aviation fuel, commonly referred to simply as “SAF”. SAF recycles CO2 emissions that were emitted previously and subsequently absorbed from the atmosphere during biomass production. SAF must have the same characteristics as conventional jet fuel so that manufacturers do not need to redesign engines or aircraft, and so that fuel suppliers and airports do not need to build new fuel delivery systems. Taking into consideration that the same aircraft can be fueled in different countries, international specifications have been adopted for jet fuels.

[0283] A widely utilized standard to ensure jet fuel is fit for purpose is American Society for Testing Materials (ASTM) standard number D1655, which is incorporated by reference. ASTM DI 655 sets requirements for criteria such as composition, volatility, fluidity, combustion, corrosion, thermal stability, contaminants, and additives, to ensure that the fuel is compatible when blended.

[0284] The drop-in condition is a major requirement for the aviation industry, to ensure safety and performance that is equivalent to conventional Jet A or Jet Al kerosene. The standard regulating the technical certification of SAF is ASTM D7566, which is incorporated by reference. The alcohol-to-jet (ATJ) pathway has been approved by ASTM for incorporation into ASTM D7566 in 2018 using ethanol at a blend limit of 50%. The ATJ process utilizes dehydration, oligomerization, and hydroprocessing to convert ethanol to hydrocarbon fuel blending components. There are other approved pathways for SAF, and additional pathways may be approved in the future, such as catalyzed reactions of sugars into hydrocarbons.

[0285] In various embodiments, alcohols such as ethanol are converted to sustainable gasoline, sustainable diesel fuel, sustainable aviation fuel, or a combination thereof. Such processes employ a number of reactors, including for example a biomass digestor, a hydrolysis reactor, a fermentor, a catalytic reactor, and potentially other reactors.

[0286] Some embodiments utilize a business system in which steps of a method are practiced at different sites and potentially by different corporate entities, acting in conjunction with each other in some manner, such as in a joint venture, an agency relationship, a toll producer, a customer with restricted use of product, etc. For example, biomass may be pretreated at a first site to generate a pretreated biomass stream that is then sent to a second site for processing in the FBRS.

[0287] The recited method and system options and embodiments may be utilized entirely or partially. Some embodiments may omit method steps or system components. Some embodiments include other method steps or system components that are not explicitly taught herein but are conventional in the chemical-engineering and biorefinery arts. Solid, liquid, and gas streams produced or existing within the biorefinery can be independently recycled, passed to subsequent steps, or removed / purged from the process at any point.

[0288] The throughput, or process capacity, can vary widely from small experimental units to full operations, including any pilot, demonstration, or semicommercial scale. In various embodiments, the process capacity (for feedstocks, products, or both) is at least about 0.1 tons / day (all tons are metric tons), 1 ton / day, 10 tons / day, 100 tons / day, 500 tons / day, 1000 tons / day, 2000 tons / day, 3000 tons / day, 4000 tons / day, 5000 tons / day, or higher.

[0289] The biorefinery may be a retrofit to an existing plant. In other embodiments, the biorefinery is a greenfield plant. As will be appreciated by a person skilled in the art, the principles of this disclosure may be applied to many biorefinery plant configurations beyond those explicitly disclosed or described in the drawings hereto. Various combinations are possible and selected embodiments from some variations may be utilized or adapted to arrive at additional variations that do not necessarily include all features disclosed herein.

[0290] In this detailed description, reference has been made to multiple embodiments of the invention and non-limiting examples relating to how the invention can be understood and practiced. Other embodiments that do not provide all of the features and advantages set forth herein may be utilized, without departing from the spirit and scope of the present invention. This invention incorporates routine experimentation and optimization of the methods and systems described herein. Suchmodifications and variations are considered to be within the scope of the invention defined by the claims. The headings in the detailed description shall not be construed as limiting the invention.

[0291] All publications, patents, and patent applications cited in this specification are herein incorporated by reference in their entirety as if each publication, patent, or patent application were specifically and individually put forth herein. In case of conflict between text that is explicitly set forth herein and information that is incorporated by reference, the explicit text in this patent application shall control over the text incorporated by reference.

[0292] This disclosure hereby incorporates by reference herein U.S. Patent App. Pub. No. 2021 / 013103 Al by Zebroski, published on May 6, 2021, for its teachings of various process and system options that are applicable to embodiments of this invention.

[0293] This disclosure also hereby incorporates by reference herein U.S. Patent App. Pub. No. 2023 / 0287468 Al by Zebroski, published on September 14, 2023, for its teachings of various process and system options that are applicable to embodiments of this invention.

[0294] This disclosure also hereby incorporates by reference herein U.S. Patent App. Pub. No. 2022 / 0304051 Al by Zebroski, published on September 28, 2023, for its teachings of various process and system options that are applicable to embodiments of this invention.

[0295] This disclosure also hereby incorporates by reference herein U.S. Patent App. Pub. No. 2023 / 0313251 Al by Zebroski, published on October 5, 2023, for its teachings of various process and system options that are applicable to embodiments of this invention.

[0296] This disclosure also hereby incorporates by reference herein U.S.Patent App. No. 18 / 597,459 by Zebroski, filed on March 6, 2024, for its teachings of various process and system options that are applicable to embodiments of this invention.

[0297] Where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certain of the steps may be performed concurrently in a parallel process when possible, as well as performed sequentially.

[0298] Therefore, to the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the appended claims, it is the intent that this patent will cover those variations as well. The present invention shall only be limited by what is claimed.EXAMPLES

[0299] Example 1: FBRS for Separating a Pretreated Biomass Stream Into a Solid-Rich Material and a Liquid-Rich Material.

[0300] In this example, a fiber-bed reactive separator (FBRS) is provided in the form of a filter press equipped with wash and membrane squeeze capability, as shown in FIG. 2. The FBRS is compared against a conventional four-stage countercurrent centrifugation and re-slurry system, as shown in FIG. 3. A pretreated biomass stream is obtained from fractionation cane straw with an AVAP pretreatment using SO2, ethanol, and water at typical conditions as described in the specification.

[0301] Operation of the four-stage centrifuge and re-slurry system on AVAP- pretreated biomass at plant scale produces a residual fines concentration in the centrate of 0.30 wt% and 0.71 wt%, when operated with a g-force (gravitational force equivalent) of 3751 g and 3042 g, respectively. The separation effectiveness of the four-stage centrifuge and re-slurry system is partly limited by the specific gravity of the fines. Because the pretreated biomass solids are heterogeneous in composition and density, gravity-based separation is inherently limited in its ability to remove these fines. In contrast, the FBRS achieves fines removal via formation of a fiber bed, eliminating the impact of the specific gravity of the fines. In the plant-scale filter press with countercurrent washing, the average residual fines content in the filtrate is measured at 0.03 wt%, demonstrating a clear improvement by at least an order of magnitude, compared to the conventional four-stage centrifuge and re-slurry system.-n -

[0302] Dissolved solids retention in the fiber is also significantly reduced with the FBRS. From plant-scale operation of the four-stage centrifuge and re-slurry system, the average residual dissolved solids in the cake is 14.2 wt% (dry basis). By contrast, the FBRS achieves an average dissolved solids concentration of 12.7 wt% (dry basis) in the fiber, while using 38% less wash liquid. This lower wash-liquid requirement minimizes the load on downstream chemical recovery operations, offering further process efficiency gains. Thus, when considering the separation and wash performance, the FBRS provides superior product purity by reducing both fine suspended solids in the liquid phase (filtrate) and dissolved solids remaining in the fiber bed.

[0303] Operation of the four-stage centrifuge and re-slurry system described above (FIG. 3) requires five horizontal decanters in series, each with its own feed pump, plus four agitated re-slurry tanks. This arrangement incurs a specific power consumption of 1.80 kWh per kilogram of dry washed solids. By contrast, the FBRS (FIG. 2) relies on just one hydraulic closure pump, a single feed pump, a wash liquid feed pump, and optionally a filter plate membrane squeeze pump. In this example, the total power consumption for the FBRS system is less than 0.21 kWh per kilogram of dry washed solids, representing a substantial reduction in electrical power use — nearly an order of magnitude lower. Thus, when considering energy efficiency, the FBRS offers significant electrical power savings.

[0304] In addition to electrical energy savings in the fiber separation and wash, the FBRS also reduces the thermal and electrical energy required for recovery of the pretreatment chemicals, by reducing the volume of wash liquid needed to achieve an equivalent wash of the fiber. In this example, the reduced energy consumption results in a 29.5% reduction in steam required for the chemical recovery operation in the FBRS, when compared to the four-stage centrifuge and re-slurry system. Thus, when further considering energy efficiency, the FBRS offers significant thermal power savings, due to the reduction of wash liquid — in addition to the significant electrical power savings described in the preceding paragraph.

[0305] The FBRS has also been shown to result in preservation of fiber integrity during separation. A MorFi Compact fiber analyzer (TECHPAP SAS, Grenoble, France) is used to analyze fibers obtained from the FBRS as well as fromthe four-stage centrifuge and re-slurry system. FIG. 17 is an optical micrograph (scale bar 400 microns) of fibers obtained following separation using the four-stage centrifuge and re-slurry system. FIG. 18 is an optical micrograph (scale bar 400 microns) of fibers obtained following separation using the FBRS.

[0306] It can be clearly observed from FIGS. 17 and 18 that the FBRS results in less fiber breakage, compared to centrifuge and re-slurry system. The gentle handling achieved in the filter press enables fiber preservation arising. Also, the MorFi Compact fiber analysis shows that the area depicted in FIG. 17 is about 84% fines, whereas the area depicted in FIG. 18 is about 33% fines, which is a significant improvement for the FBRS over the centrifuge and re-slurry system. The MorFi Compact fiber analysis also indicates that the average fiber length is about 15% higher for the FBRS compared to the centrifuge and re-slurry system. In applications where maintaining fiber length is important, such as in the production of nanocellulose, the preservation of fiber integrity is critical. Furthermore, longer fibers promote a more-porous fiber bed, which in turn enhances the efficiency of not only the separation and washing but also any downstream reaction or mass-transfer operations, as they also rely on fiber-bed porosity.

[0307] Example 2: FBRS for Separating a Pretreated Biomass Stream Into a Solid-Rich Material and a Liquid-Rich Material, With Sequential Chemical Reactions and / or Mass-Transfer Operations.

[0308] In this example, a fiber-bed reactive separator (FBRS) is provided in the form of a filter press equipped with wash and membrane squeeze capability, as shown in FIG. 2. A pretreated biomass stream is obtained from fractionation cane straw with an AVAP pretreatment using SO2, ethanol, and water at typical conditions as described in the specification. The pretreated biomass stream is fed to the FBRS and operated to separate the liquid phase from the solid phase, to generate a solid-rich material that remains in the fiber bed, plus a liquid-rich material that is directed to an output liquid stream.

[0309] Because the fiber has been separated from the liquids, and is isolated in concentrated form, reactants and catalysts can be efficiently introduced in the liquid phase or gas phase. FIG. 4 depicts the introduction of a liquid-phase reactant orcatalyst to the fiber isolated in a FBRS in a once-through configuration. FIG. 5 depicts the introduction of a liquid-phase reactant or catalyst to the fiber in a recirculating-liquid configuration. FIG. 6 and 7 depict the introduction of a gas-phase reactant or catalyst to the fiber in the FBRS, which can be performed in either a once- through configuration (FIG. 6) or a recirculating configuration (FIG. 7). Reactants or catalysts in either phase can be applied successively, as required by the reaction scheme, and can be applied at elevated or depressed temperatures to control the reaction temperature. This functional flexibility allows for gas-phase, liquid-phase, or solid-phase (e.g., chemisorption, or reactive desorption) reaction schemes to be efficiently executed with a minimum use of reactants and / or catalysts.

[0310] The FBRS also allows mass-transfer operations to be performed before, after, or between reaction steps, to facilitate the absorption / stripping of molecules to / from the residual liquid phase, or the adsorption / desorption of molecules to / from the fiber. These mass-transfer operations can be performed in the FBRS (FIG. 8), in subsequent equipment, or both (FIG. 9). A good example illustrating a FBRS being used for both reaction and mass transfer operations is the stripping of residual sulfur-containing compounds from AVAP-pretreated lignocellulosic fiber. An exemplary operation is presented in detail in Example 4.

[0311] FIG. 10 illustrates the feeding stage of the FBRS, in which the fiber bed is formed. For a filter press, one or more feed slurries enter the press, filling the filter-lined chambers between the plates. The feed can enter at the center of the plate, or through ports at other locations on the plate. The liquid passes through the filter and is passed from the press to the digestion-liquor receiver. The fiber is retained by the filter and accumulates to form a fiber bed in the chamber between the plates. At the end of this process, there can be an evacuation of the feed port (core blow), in which the residual feed material is purged from the feed port, back into the appropriate slurry feed tank.

[0312] FIG. 11 illustrates an optional liquid expression stage in the FBRS, wherein residual liquid is expelled from the fiber bed using a gas. In a filter press, this may be accomplished by injecting a compressed gas through a port at the top of the fiber bed chamber on one side of the fiber bed. The gas is then forced through the fiber bed to expel the liquid through a port located at the bottom of the plate formingthe other half of the chamber. This expressing of residual liquid can be accomplished by injecting the gas through a port at the top right of the plate, then exiting the chamber at the bottom left of the opposing plate, and then injecting the gas through a port at the top left of a plate, exiting the chamber through a port at the bottom right of the opposing plate — thereby creating a “cross blow” of the fiber bed. Following this principle, gas can be forced through the filter bed using any pairing of ports from opposing plates for entry and exit of the gas. Gas can also be injected through the feed port, exiting through any other port. The gas used for expressing residual liquid can be air, an inert gas (e.g., N2), a reactant, or another gas. The gas may be the same gas used for a stripping operation in another step.

[0313] Another optional stage that can be used to express residual liquid from the FBRS fiber bed is a squeeze stage. This can be accomplished in a number of different ways for different equipment, but for a filter press this is accomplished by means of inflating a membrane attached to one or both of the plates on the surface forming the chamber containing the fiber bed. When a liquid or gas is injected into a void behind the membrane, the membrane is pressed toward the center of the chamber, compressing the fiber bed, and expressing residual liquid from the fiber. Once the liquid has been expressed from the fiber, the fluid pressure in the space behind the membrane is released, allowing the membrane to return to its original position. The squeeze stage can be executed before or after any other step once a fiber bed has been formed. In filter-press operation, the squeeze stage also serves to assist in forming a cohesive fiber bed that will release from the plates upon opening of the press.

[0314] Another optional stage that can be applied to the fiber bed in the FBRS is a fiber wash. The wash stage can be performed before or after any other stage once a filter bed has been formed. The wash can be applied in a cross-current, countercurrent, or co-current configuration with as many stages and different wash liquids as are beneficial for the process. The wash liquid temperature, pressure, and flow rate can all be adjusted to meet the needs of the process and conform with the constraints of the equipment. The wash filtrates produced in each wash stage may be reused in the FBRS, in other parts of the process, or disposed of.

[0315] FIGS. 12, 13, and 14 illustrate the process flow for a four-stage countercurrent FBRS wash using a filter press. After the digestion liquor has been separated from the digested biomass, forming the fiber bed as depicted in FIG. 10, the first wash can be applied to the fiber bed. FIG. 12 shows the flow path of the first wash liquid exiting from the second wash filtrate tank, passing through temperatureadjustment equipment to achieve the optimum wash temperature, and then entering the filter press through the filter press feed port and / or the filtrate ports at the bottom of the press. The first wash liquid introduced through the feed port flows through the fiber bed and into the filtrate ports of the press, forming the first wash filtrate (loaded wash liquid). The first wash liquid can then also be passed through the fiber bed in a “cross wash” configuration which utilizes the same ports used for the “cross blow” but in reverse — from bottom right to top left, and bottom left to top right — forming additional first wash filtrate (loaded wash liquid).

[0316] FIG. 13 shows the path of the second wash liquid, exiting the third wash filtrate tank, optionally mixing with a flow of wash liquid A to achieve the desired second wash liquid composition, passing through temperature adjustment, then following the same flow path through the filter press as the first wash liquid. Upon exiting the filter press, the liquid is now the second wash filtrate, and is sent to the second wash filtrate tank. This countercurrent wash process can be repeated to provide as many wash stages as the process requires. In this example, there are four wash stages, so this step would be repeated once more taking the third wash liquid from the fourth wash filtrate tank. If the composition of the second wash liquid is to be different than that of the third wash liquid, an amount of wash liquid B may be blown down from the fourth wash filtrate tank. This amount of liquid will be roughly equal to the amount of wash liquid A that will be added in the second wash step.

[0317] FIG. 14 shows the path of the N* wash — in this example, the fourth wash. Fresh wash liquid B enters the system, following the same flow path as the other wash liquids, passing through the temperature adjustment, through the press, and into the N* wash filtrate tank — in this example, the fourth wash filtrate tank.

[0318] A reaction stage can be incorporated into the FBRS at any point after a fiber bed has been established. Multiple reaction stages can be inserted as desired, and can be executed successively or interspersed between other stages, such as wash,liquid expression, or mass-transfer stages. The reaction may occur in the liquid phase of the fiber bed, in the suspended solid phase, or in both of these phases. Reactants and / or catalysts can be introduced to the fiber bed in the liquid phase or the gas phase, and delivered in a once-through configuration or a recirculating configuration.

[0319] FIG. 15 illustrates the introduction of a reactant or catalyst to the fiber bed of a filter press in a recirculating liquid-phase configuration. The temperature, pressure, and flow rate of the reactant or catalyst can be adjusted to optimize the process and / or accommodate equipment constraints. The reactant or catalyst flow path may follow the same flow path as the wash liquid flow path described above, or an alternative flow path may be used. The reactant or catalyst reservoir may be a tank, a pressure vessel, or any other equipment capable of containing liquid.Additional reactant or catalyst may be added to, or removed from, the loop as needed. Catalyst may be regenerated in the loop or in an external unit operation. Excess carrier liquid (such as water or other) can be removed from the loop to maintain the optimum reactant or catalyst concentration.

[0320] FIG. 16 illustrates the introduction of a reactant or catalyst to the fiber bed of a filter press in a once-through gas-phase configuration. The temperature, pressure, and flow rate of the reactant or catalyst can be adjusted to optimize the process and / or conform to the equipment constraints.

[0321] A mass-transfer stage can be incorporated into the FBRS at any point after the fiber bed has been established. Multiple mass-transfer stages can be inserted if needed, and can be executed successively or interspersed between other stages, such as washing, liquid expressing, or reaction stages. The mass transfer can take place in the liquid phase of the fiber bed, or in the suspended solid phase of the fiber bed, or in both of these phases. The mass transfer may utilize any applicable mass-transfer operations, including but not limited to absorption, adsorption, stripping, desorption, and chemisorption.

[0322] FIG. 9 illustrates a mass-transfer stage that takes place in two pieces of equipment. In this example, the first piece of equipment is a filter press. The second piece of equipment, the solids mass-transfer vessel, is designed specifically for stripping volatile compounds from the concentrated fiber. While the fiber is still in the filter press, the stripping gas is passed through the fiber bed following the sameflow path used for the gas expression of residual liquid. After the fiber has been discharged from the filter press, the stripping operation is continued in the solids mass-transfer vessel that is designed for mass-transfer operations involving gases and particulate solids, or gases and particulate solids coated in liquid. The gas used in the solids mass-transfer vessel may be the same as that used in the filter press, or different, or a combination of several different gasses.

[0323] The final stage of the FBRS is the discharge of the fiber bed to recover the solid-rich material. The fiber is discharged in a condition that is best suited to the downstream operations, and can take place continuously or intermittently.

[0324] Example 3: Acid-Mediated SO2 Production and Removal in a FBRS with Reaction Triggering.

[0325] This example demonstrates how an FBRS enables the efficient execution of a pretreatment-chemical recovery reaction from washed digested fiber. This example also demonstrates the execution of a mass-transfer operation.

[0326] The digested biomass is AV AP -pretreated cane straw. The wash liquids used are a mixture of ethanol and water (deionized water for final washing). The stripping gas is 99.998 vol% pure industrial nitrogen. The reactant used is 0.525 M phosphoric acid (H3PO4), although any acid capable of achieving the required pH may be used. In this example, reaction triggering uses a change in pH, which is performed by adding H3PO4.

[0327] The FBRS in this experiment is a bench-scale cylindrical filter press apparatus 7 cm in diameter, and 13.5 cm in height. Wash liquids and reactant are applied to the fiber bed through stainless steel tubing running from a stainless steel canister to the filter press. The liquids are placed in the canister, the canister is sealed, and nitrogen is applied to the canister through a pressure regulator to move the liquid through the fiber bed. The filtrate discharge of the press is connected to a tube.When liquid is being removed from the press, the tube is placed in a container on a digital scale to allow for the measurement of the liquid flow rate. When stripping gas is being removed from the press, a sintered sparger is connected to the end of the tube and placed near the bottom of a 500 mL glass cylinder filled with 300 to 350 mL of deionized (DI) water. A magnetic stirring rod is used to agitate the water in thecylinder, and a temperature-compensated pH probe is inserted into the water to provide a continuous pH reading.

[0328] In this example, the FBRS is first used to separate the AVAP digestion liquor from AVAP fiber solids, forming a fiber bed. The fiber is then washed to remove residual digestion liquor chemicals. In the AVAP biomass fractionation process, residual sulfur containing compounds, including sulfite (SO32), bisulfite (HSO3 ), sulfurous acid (H2SO3), and dissolved sulfur dioxide (SO2) remain in the fiber following separation and washing. To remove these compounds, a stripping operation is executed in the FBRS, wherein the fiber, containing approximately 50% moisture by weight, is contacted with an inert stripping gas, in this case nitrogen (N2). The nitrogen strips the SO2 from the aqueous phase within the fiber’s moisture into the gas phase, producing a loaded stripping gas containing SO2. The flow of stripping gas is maintained until the concentration of SO2 in the loaded stripping gas falls below a predetermined threshold, at which point the stripping gas flow is temporarily halted.

[0329] To enhance SO2 removal, an acid is introduced to the fiber bed to produce hydronium in the liquid phase, thereby reducing the pH of the liquid phase, and shifting the chemical equilibria among sulfite, bisulfite, sulfurous acid, and dissolved SO2 toward the formation of SO2, as described by the following reaction network:HSO3 + H+H2SO3H2SO3SO2(aq) + H2OSO2(aq) SO2(g)

[0330] The reduced pH favors the formation of dissolved SO2, which is subsequently desorbed into the stripping gas. Following H3PO4 application and equilibrium adjustment, excess acid is expressed from the fiber bed, and the flow of stripping gas is resumed, contacting the fiber bed to desorb additional SO2 into the loaded stripping gas, thereby further reducing the residual digestion chemical content of the fiber. This process involving the formation of hydronium and subsequentshifting of the chemical equilibria among the four species mentioned may be performed prior to the application of any stripping gas, between applications of stripping gas as described above, or in other combinations of reaction and stripping steps. A final wash step can also be applied to recover the acid, but was not performed in this example.

[0331] The experiment in this example is performed according to the following procedure:

[0332] 1. AV AP -pretreated cane straw is placed in the filter press. Nitrogen is applied to the headspace above the AVAP-pretreated cane straw to provide pressure for the solid / liquid separation, and the fiber bed is then washed to remove residual dissolved solids. The pH of the final wash water is measured to be 3.75.

[0333] 2. Nitrogen stripping gas is then passed through the fiber bed at a flow rate of 0.9 standard liters per minute at ambient temperature (21 °C). The loaded stripping gas exiting the press is sparged through the agitated column of DI water.The pH of the DI water is monitored and recorded every 60 seconds. The gas exiting the top of the DI water cylinder is monitored to ensure that all SO2 in the loaded stripping gas is absorbed in the DI water.

[0334] 3. When the pH approaches steady state, indicated by a negligible change between successive measurements, the flow of nitrogen is stopped.

[0335] 4. Reactant application: 144 g of 0.525 M phosphoric acid is passed over the filter bed at ambient temperature and then expelled from the press using nitrogen. The pH of the final reactant liquid leaving the filter press is 1.7.

[0336] 5 The flow of nitrogen stripping gas through the fiber bed is resumed at a flow rate of 0.9 standard liters per minute. The loaded stripping gas exiting the press is sparged through the agitated column of DI water. The pH of the DI water is monitored and recorded every 60 seconds.

[0337] 6. When the pH approaches steady state, indicated by a negligible change between successive measurements, the flow of nitrogen is stopped.

[0338] 7. The time course pH data from the experiment is tabulated. From the change in the pH of the DI water column and the mass of the DI water column, the mass of SO2 absorbed in the DI water is calculated. The SO2 absorbed in the DI water forms sulfurous acid, which partially dissociates. The pH decrease reflects theincrease in H+concentration due to the sulfurous acid formation and dissociation.The change in H+concentration for any increment of time ti and t2, with measured pH values at those times being pHi and pH2, respectively, is:A [H+] = 10-PH2 _ lo-ptfi ( 21)Because sulfurous acid is a weak diprotic acid and its second dissociation constant (Ka2) is much smaller than the first dissociation constant (Kai),H2SO3H++ HSO3 (Kal« 1.7 x 10“2at 25°C)(Ka2« 6.4 x 10-8at 25°C) the second dissociation step is negligible under acidic conditions and is omitted from the calculation for the purpose of this illustration. The mass of SO2 absorbed during any time increment is then represented by the equation:where: mS02is the cumulative mass of SO2 absorbed in the deionized water;[H+] is the concentration of hydrogen ions in the deionized water;Kais the dissociation constant of sulfurous acid (H2SO3), 1.7 x 102M at 25°C;mwater is the mass of the deionized water; andMWSO2is the molecular weight of sulfur dioxide, 64.07 g / mol.

[0339] FIG. 19 is a graph of the cumulative SO2 removed from the fiber bed versus the cumulative volume of nitrogen stripping gas used, in the first trial. In FIG.19, the cumulative mass of SO2 stripped from the fiber bed can be seen to be approaching steady state at approximately 70 standard liters of cumulative stripping gas flow. At this point the stripping gas flow is stopped, the acid reactant is applied, and the stripping gas flow is then restarted. Upon restart of the stripping gas flow, additional SO2 is removed from the filter bed, illustrating the effectiveness of the reaction step.

[0340] The experiment is then repeated (steps 1 through 7 listed above), except in this second trial, step 3 is not performed, and in step 4 the reactant mass used is increased to achieve a pH of 1.5 in the final reactant liquid leaving the filter press.

[0341] The time course pH data from the experiment is tabulated. From the change in the pH of the DI water column and the mass of the DI water column, the mass of SO2 absorbed in the DI water is calculated. FIG. 20 is a graph of the cumulative SO2 removed from the fiber bed versus the cumulative volume of nitrogen stripping gas used for this second trial.

[0342] The second trial illustrates the flexibility and resulting efficiency the FBRS offers for the execution of reaction and mass-transfer operations. With no additional cycle time, and no additional residual reactant left on the fiber, additional digestion chemical can be recovered from the fiber bed, while simultaneously reducing the volume of stripping gas used and the time required for the stripping step.

Claims

CLAIMSWhat is claimed is:

1. A method of reactive separation of biomass-derived materials, said method comprising:(a) providing a pretreated biomass stream that contains a solid phase and a liquid phase, wherein said solid phase comprises a first biomass-derived material, and wherein said liquid phase comprises water and a second biomass-derived material that is dissolved or suspended in said liquid phase;(b) introducing said pretreated biomass stream to a fiber-bed reactive separator, wherein said pretreated biomass stream forms a fiber bed;(c) optionally, applying a pre-separation reaction trigger to said fiber bed to cause a pre-separation chemical reaction of at least one component within said liquid phase and / or at least one component within said solid phase, wherein said preseparation chemical reaction takes place in situ within said fiber bed;(d) separating at least a portion of said liquid phase from said solid phase, to generate a solid-rich material and a liquid-rich material, wherein said solid-rich material remains in said fiber bed, and wherein said liquid-rich material is directed to an output liquid stream;(e) optionally, applying a post-separation reaction trigger to said solid-rich material, while said solid-rich material is still contained in said fiber bed, to cause a post-separation chemical reaction of at least one component within said solid-rich material; and(f) recovering said solid-rich material from said fiber-bed reactive separator, wherein at least one of steps (c) or (e) is conducted.

2. The method of claim 1, wherein said pretreated biomass stream is a pretreated lignocellulosic biomass stream.

3. The method of claim 1, wherein said pretreated biomass stream is a slurry containing said solid phase and said liquid phase.

4. The method of claim 1, wherein said pretreated biomass stream is in the form of wet solids in which said liquid phase does not form a free liquid phase within said solid phase.

5. The method of claim 1, wherein said pretreated biomass stream further comprises one or more process aids.

6. The method of claim 1, wherein said first biomass-derived material is a cellulose-rich material.

7. The method of claim 1, wherein said first biomass-derived material is a ligninrich material.

8. The method of claim 1, wherein said second biomass-derived material is a hemicellulose-rich material.

9. The method of claim 1, wherein said second biomass-derived material is a lignin-rich material.

10. The method of claim 1, wherein said fiber bed is an immobilized fiber bed.

11. The method of claim 1, wherein said fiber bed is a moving fiber bed.

12. The method of claim 1, wherein said fiber-bed reactive separator is a filter press.

13. The method of claim 12, wherein said filter press is a squeeze-plate filter press containing a plurality of immobilized fiber beds spaced apart by plates and / or membranes.

14. The method of claim 1, wherein said liquid phase further comprises a hydrolysis catalyst, and wherein said hydrolysis catalyst is optionally selected from the group consisting of sulfur dioxide, sulfonic acid, lignosulfonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, phosphoric acid, nitric acid, carbonic acid, and combinations thereof.

15. The method of claim 1, wherein said liquid phase further comprises a solvent for lignin.

16. The method of claim 15, wherein said solvent for lignin is a Ci-Ce alcohol.

17. The method of claim 16, wherein said Ci-Ce alcohol is methanol, ethanol, or a combination thereof.

18. The method of claim 1, wherein said liquid phase further comprises a sulfonic acid, a lignosulfonic acid, a Ci-Ce organic acid, a fatty acid, a Ci-Ce aldehyde, a Ci- Ce ketone, a Ci-Ce polyol, or a combination thereof.

19. The method of claim 1, wherein said method further comprises, following step (b), mechanically squeezing said fiber bed to enhance separation of said liquid phase from said solid phase.

20. The method of claim 19, wherein said mechanically squeezing is conducted between steps (b) and (c).

21. The method of claim 19, wherein said mechanically squeezing is conducted during step (c).

22. The method of claim 19, wherein said mechanically squeezing is conducted between steps (c) and (d).

23. The method of claim 19, wherein said mechanically squeezing is conducted during step (d).

24. The method of claim 19, wherein said mechanically squeezing is conducted after step (d).

25. The method of claim 19, wherein said mechanically squeezing is accomplished using a squeeze liquid that applies pressure directly to said fiber bed.

26. The method of claim 19, wherein said mechanically squeezing is accomplished using a squeeze liquid that enters a membrane, and wherein said membrane applies pressure to said fiber bed.

27. The method of claim 19, wherein said mechanically squeezing is accomplished using a squeeze gas that applies pressure directly to said fiber bed.

28. The method of claim 19, wherein said mechanically squeezing is accomplished using a squeeze gas that enters a membrane, and wherein said membrane applies pressure to said fiber bed.

29. The method of claim 19, wherein said mechanically squeezing is accomplished by physical force applied between an outer plate and said fiber bed.

30. The method of claim 19, wherein said mechanically squeezing is accomplished by physical force applied between a membrane and said fiber bed.

31. The method of claim 1, wherein said method further comprises, following step (b), blowing a blow gas through said fiber bed and / or through said solid-rich material.

32. The method of claim 31, wherein said blowing is conducted between steps (b) and (c).

33. The method of claim 31, wherein said blowing is conducted during step (c).

34. The method of claim 31, wherein said blowing is conducted between steps (c) and (d).

35. The method of claim 31, wherein said blowing is conducted during step (d).

36. The method of claim 31, wherein said blowing is conducted after step (d).

37. The method of claim 31, wherein said blow gas passes through said fiber bed in cross flow.

38. The method of claim 31, wherein said blow gas is selected from the group consisting of air, N2, CO2, Ar, He, and combinations thereof.

39. The method of claim 31, wherein said blow gas contains no greater than 1 mol% O2.

40. The method of claim 31, wherein said blow gas contains no greater than 0.1 mol% O2.

41. The method of claim 31, wherein said blow gas contains no greater than 0.01 mol% O2.

42. The method of claim 1, wherein said method further comprises, following step (b), washing said fiber bed using a wash fluid.

43. The method of claim 42, wherein said washing is conducted between steps (b) and (c).

44. The method of claim 42, wherein said washing is conducted during step (c).

45. The method of claim 42, wherein said washing is conducted between steps (c) and (d).

46. The method of claim 42, wherein said washing is conducted during step (d).

47. The method of claim 1, wherein said washing is conducted after step (d).

48. The method of claim 42, wherein said wash fluid passes through said fiber bed in cross flow.

49. The method of claim 42, wherein said fiber-bed reactive separator contains a plurality of immobilized fiber beds spaced apart by plates and / or membranes, and wherein said wash fluid countercurrently passes through said plurality of immobilized fiber beds, relative to flow direction of said liquid phase.

50. The method of claim 42, wherein said wash fluid is a wash liquid.

51. The method of claim 50, wherein said wash liquid is selected from the group consisting of water, a Ci-Ce alcohol, a Ci-Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a fatty acid, a sulfonic acid, a lignosulfonic acid, and combinations thereof.

52. The method of claim 50, wherein said wash liquid is water.

53. The method of claim 50, wherein said wash liquid is a mixture of water and ethanol.

54. The method of claim 42, wherein multiple washing steps are employed, and wherein each of said multiple washing steps uses an independently selected wash fluid.

55. The method of claim 42, wherein said wash fluid is a wash vapor.

56. The method of claim 55, wherein said wash vapor is selected from the group consisting of steam, nitrogen, argon, helium, carbon dioxide, a Ci-Ce alcohol, a Ci- Ce polyol, a Ci-Ce organic acid, a Ci-Ce aldehyde or ketone, a sulfonic acid, a lignosulfonic acid, and combinations thereof.

57. The method of claim 42, wherein said wash fluid passes through a core of said fiber bed.

58. The method of claim 42, wherein said fiber-bed reactive separator contains a plurality of immobilized fiber beds spaced apart by plates and / or membranes, and wherein said wash fluid cocurrently passes through said plurality of immobilized fiber beds, relative to flow direction of said liquid phase.

59. The method of claim 1, wherein said pre-separation reaction trigger and / or said post-separation reaction trigger comprises a change in pH within said fiber bed.

60. The method of claim 59, wherein said change in pH is a pH change of said liquid phase.

61. The method of claim 59, wherein said change in pH is a pH change associated with said solid phase.

62. The method of claim 59, wherein said change in pH causes pH to be adjusted to about 4 or less.

63. The method of claim 59, wherein said change in pH causes pH to be adjusted to about 3 or less.

64. The method of claim 59, wherein said change in pH causes pH to be adjusted to about 2 or less.

65. The method of claim 59, wherein said change in pH causes pH to be adjusted to a pH selected from about 1.0 to about 2.0.

66. The method of claim 59, wherein said change in pH causes pH to be adjusted to a pH selected from about 0.5 to about 1.5.

67. The method of claim 59, wherein said change in pH is accomplished by adding an inorganic acid, an organic acid, or a combination thereof to said fiber bed.

68. The method of claim 59, wherein said liquid phase further comprises sulfur dioxide and / or a compound derived therefrom, wherein said pre-separation reaction trigger and / or said post-separation reaction trigger comprises a reduction in pH within said fiber bed, and wherein said reduction in pH shifts a sulfite-species chemical equilibrium toward a higher concentration of free SO2 in said liquid phase.

69. The method of claim 68, wherein said compound derived therefrom is a sulfonic acid.

70. The method of claim 68, wherein said compound derived therefrom is a lignosulfonic acid.

71. The method of claim 68, wherein said compound derived therefrom is a sulfite salt and / or a bisulfite salt.

72. The method of claim 68, wherein said method further comprises separating said free SO2 from said liquid phase, while said liquid phase is still present in said fiber bed.

73. The method of claim 68, wherein said method further comprises separating said free SO2 from said liquid phase, during step (d).

74. The method of claim 68, wherein said method further comprises separating said free SO2 from said liquid-rich material, after step (d).

75. The method of claim 68, wherein said method further comprises, following step (b), blowing a blow gas through said fiber bed, and wherein said free SO2 is captured in said blow gas.

76. The method of claim 68, wherein said method further comprises, following step (b), washing said fiber bed using a wash fluid, and wherein said free SO2 is captured in said wash fluid.

77. The method of claim 76, wherein said wash fluid is a wash vapor.

78. The method of claim 1, wherein said pre-separation reaction trigger and / or said post-separation reaction trigger comprises a change in temperature of said fiber bed.

79. The method of claim 78, wherein said change in temperature causes the temperature of said fiber bed to be from about 50°C to about 200°C.

80. The method of claim 1, wherein said pre-separation reaction trigger and / or said post-separation reaction trigger comprises a change in pressure within said fiber bed.

81. The method of claim 80, wherein vacuum is applied to said fiber bed.

82. The method of claim 1, wherein said pre-separation reaction trigger and / or said post-separation reaction trigger comprises addition of a chemical reactant to said fiber bed.

83. The method of claim 82, wherein said chemical reactant is added via displacement, absorption, adsorption, chemisorption, or combinations thereof.

84. The method of claim 82, wherein said chemical reactant is an inorganic acid.

85. The method of claim 82, wherein said chemical reactant is an organic acid.

86. The method of claim 82, wherein said chemical reactant is selected from the group consisting of SO2, CO2, CO, H2, H2O, CH4, NH3, HNO3, H2SO4, H3PO4, HC1, Ch, O2, O3, H2O2, NO, NO2, and combinations thereof.

87. The method of claim 86, wherein said chemical reactant is SO2.

88. The method of claim 87, wherein said SO2 reacts with lignin that is, or is contained in, said first biomass-derived material, thereby increasing sulfur content of said lignin.

89. The method of claim 87, wherein said SO2 reacts with lignin that is, or is contained in, said second biomass-derived material, thereby increasing sulfur content of said lignin.

90. The method of claim 82, wherein cellulose contained in said solid phase reacts with said chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to glucose and / or other cellulose sugars.

91. The method of claim 82, wherein hemicellulose contained in said solid phase reacts with said chemical reactant to enhance hydrophilicity and / or enzymatic digestibility to xylose and / or other hemicellulose sugars.

92. The method of claim 82, wherein hemicellulose contained in said liquid phase reacts with said chemical reactant to generate hemicellulose sugars.

93. The method of claim 1, wherein said solid-rich material recovered in step (f) has a solids concentration of at least 50 wt% solids.

94. The method of claim 1, wherein said solid-rich material recovered in step (f) has a solids concentration of at least 75 wt% solids.

95. The method of claim 1, wherein said method further comprises recovering a pretreatment chemical from said liquid-rich material, and reusing said pretreatment chemical in pretreatment of fresh biomass.

96. The method of claim 1, wherein said method further comprises further processing of said solid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, cellulose, nanocellulose, pulp, paper, hemicellulose, lignin, or a combination thereof.

97. The method of claim 1, wherein said method further comprises further processing of said liquid-rich material to generate fermentable sugars, fermentation products, catalytically convertible sugars, hemicellulose, lignin, or a combination thereof.

98. The method of claim 97, wherein said further processing of said liquid-rich material does not include an evaporation step prior to fermentation and / or catalysis.

99. The method of claim 1, wherein said method is conducted in batch.

100. The method of claim 1, wherein said method is conducted continuously or semi-continuously.

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