Recovery of valuable components from biomass

Abstract

A method for separating and recovering compounds from biomass is provided. In this method, an aqueous extraction fluid (1) in an essentially gaseous phase, such as steam, is propagated through a reaction zone (10A) containing a biomass feedstock. As the extraction fluid (1) advances through the biomass feedstock, under predetermined reaction conditions, the target compounds (C1, C2) separate from the essentially solid feedstock material and migrate with the extraction fluid toward the end of the reaction zone, where the target compounds are recovered in the form of an essentially liquid medium (2). This method is useful for extracting long-chain hemicellulose from cellulose-containing feedstocks.

Description

[Technical Field]

[0001] The present invention relates generally to the processing and purification of biomass feedstocks. In particular, the present invention relates to a process for separating and recovering valuable compounds and compounds from biomass feedstocks in high yields and concentrations using an aqueous solvent provided in an essentially gaseous state. [Background technology]

[0002] The sustainable use of natural resources has been on the growing list of extremely difficult goals to achieve in recent decades. Plant-derived lignocellulosic biomass is a renewable carbon resource that offers a viable alternative to fossil carbon and related compounds, particularly petroleum-derived products, especially plastics. Forestry and agriculture are increasingly turning to smart recycling methods for by-products by redirecting by-product side streams to produce value-added items. Plant cells contain a great variety of compounds, including those of clear commercial value, that make lignocellulosic biomass a valuable resource for a wide range of applications, from biomaterial and food production to energy conversion and biofuel production.

[0003] Traditional biomass extraction methods aim to isolate various components, such as cellulose fibers, hemicelluloses, and / or various (volatile) aromatic species, and include solvent extraction, steam distillation, steam explosion, and pressurized hot water extraction.

[0004] Steam distillation is a process used to recover high-boiling, volatile (organic) compounds from inert solids or liquids using superheated steam. Steam is transported through the material, where the target compounds volatilize by absorbing heat from the steam, and are then carried away by the steam and drawn toward a condenser. The resulting vapor phase is cooled and condensed, after which the aqueous phase is separated from the organic phase. This technique is commonly used, for example, in the extraction of essential oils from plants, but not in the production of fibrous components and / or polysaccharides.

[0005] Steam explosion is one of the most common techniques for physicochemical pretreatment of lignocellulosic biomass to make biomass fibers accessible and improve the recovery of sugars and other useful compounds from the biomass. Biomass feedstock is treated with saturated steam at medium or high pressure (0.6-5 MPa) at high temperatures (160-260 °C) for a short period (a few seconds to a few minutes), followed by rapid pressure release. The main drawback of this procedure is the formation of toxic and / or inhibitory compounds that can cause complete or partial degradation of hemicellulose species and further degradation of plant cell wall polymers.

[0006] Treating cellulose material with steam in a batch or continuous (screw) reactor using steam explosion technology is disclosed in U.S. Patent Application Publication No. 2019 / 177292 (Marckmann et al.). The patent publication discloses a method and apparatus for producing target compounds, such as phenolic compounds, furans, furfurals, and organic acids, from cellulose material. The steam-exploded steam is then directed to a steam separation device, which separates the gas phase containing the target compounds from the solids. The steam containing the target phenolic compounds and / or organic acids is then condensed, and the steam-treated cellulose-containing solids can be transferred to another reactor for saccharification or other uses related to bioethanol production.

[0007] A process for fractionating sugarcane bagasse into a premium cellulose pulp with a high alpha cellulose content by treating the biomass with steam in a steam explosion batch reactor is further disclosed in U.S. Patent Application Publication No. 2010 / 276093 (Varma), in which steam is used as the hydrolysis chemical.

[0008] Another common method for biomass pretreatment is pressurized hot water extraction (PHWE), in which a solvent is pumped into an extraction chamber placed in a heated jacket at a desired temperature. The chamber containing the biomass is heated, filled with the extraction solvent (water), and then pressurized. In some modifications of the PHWE method, including continuous-flow elution, preheated water may be directed into the pressurized extraction chamber. In the PHWE process, the temperature of the water is above its boiling point (100°C) but below its critical temperature (374°C). The pressure within the extraction system is high enough to maintain the water in liquid form. After the reaction is complete, the chamber is rinsed with fresh extraction solvent while maintaining the pressure within the chamber at a level appropriate for the desired flow. The extract is cooled rapidly to prevent degradation. One of the major challenges faced when implementing this method is the unnecessary dilution of the resulting extract. Additional disadvantages associated with using high temperatures in PHWE are reduced selectivity of the extraction, adequate decomposition of the extracted compounds, and the presence of other chemical reactions in the biomass matrix. Thus, higher extraction temperatures (such as about 200° C.) extract more unwanted compounds, thereby reducing selectivity and increasing the need for post-purification treatment.

[0009] Another major problem associated with biomass extraction methods that use high temperatures (e.g., 170-250°C) is the heating and / or combustion of the biomass material, which involves irreversible damage / decomposition of the extractable compounds.

[0010] Furthermore, in the field of biomass feedstock purification, steam-based methods are typically used as part of a longer process, and the extracted stream containing the target compounds typically requires further processing, either by washing, filtration, or other purification method(s).

[0011] U.S. Patent Application Publication Nos. 2010 / 263814 and 2013 / 017589 (both by Dottori et al.) disclose batch and continuous processes, respectively, for treating lignocellulosic biomass intended for use in connection with a biomass-to-ethanol process to improve the overall yield of ethanol, which process involves extraction of cellulose and hemicellulose.

[0012] Hemicellulose isolated from wood is a valuable component in the pulp, fiber, and paper industries and related products. Softwoods also contain valuable materials for the chemical and food industries. For example, xylose (a monomeric sugar contained in hemicellulose polymers), the raw material for xylitol, can be isolated in large quantities from deciduous trees. Hemicellulose extracts can be isolated by pressurized hot water extraction, in which hemicellulose is extracted in the form of a water stream. Hot water extraction methods are disclosed, for example, in WO2009 / 122018 (Ilvesniemi et al.), WO2014 / 009604 (von Schoulz), and US2019 / 112395 (Vahasalo et al.).

[0013] Thus, WO 2009 / 122018 teaches a method for extracting hemicellulose and its derivatives from fibrous biomass at temperatures above 160°C, particularly 170-240°C, and pressures of 0.2-10 MPa (2-100 bar), particularly 0.6-2 MPa (6-20 bar). The extraction uses water, which is maintained in the aqueous phase throughout the entire extraction period.

[0014] In a similar manner, WO 2014 / 009604 teaches the hot water extraction of sugars, their derivatives, and the corresponding polysaccharides from lignocellulosic biomass. The impregnation step is carried out in a closed reactor under reduced pressure, e.g., 0.8 bar. However, to obtain a high concentration of hemicellulose, the extract must be recycled through the biomass several times (e.g., 10 times).

[0015] US Patent No. 2019 / 112395 discloses a method for extracting hemicellulose from finely ground biomass (particle size less than 10 mm) using an aqueous medium such as water, aqueous solution, steam, superheated steam, and mixtures thereof. Thus, the biomass is contacted with water in a reactor vessel at a temperature of 70 to 250 °C, preferably 170 °C or less, and a pressure of 0.15 to 1 MPa (1.5 to 10 bar absolute). The hemicellulose extract produced by this method contains dispersed colloidal material, which causes the solution to become turbid and can clog downstream filters. This method requires a post-treatment step in which the extract is clarified.

[0016] Furthermore, U.S. Patent Application Publication No. 2019 / 136279 (Riva & Giordano) discloses a process for producing bioproducts from lignocellulosic biomass, in which the biomass is steamed in a continuous reactor and hemicellulose is recovered. This process allows for the recovery of both C5 and C6 sugars from the lignocellulosic biomass during the same process in the same reactor. The biomass can be pretreated by immersion, after which the biomass is introduced into a steaming reactor equipped with a plug screw feeder. After the reaction, the pressure is rapidly released via steam explosion, while the pretreated biomass is discharged from the reactor. In this process, xylan (C5 sugars) is recovered from the biomass exiting the reactor after steam explosion. Under processing conditions, intact (long-chain) hemicellulose is degraded as a result of hydrolysis that occurs during pretreatment.

[0017] Apart from the above, no alternative extraction methods have been provided that are suitable for the rapid isolation of highly pure and concentrated compounds from plant-derived biomass, without necessarily requiring post-processing and / or post-purification steps.

[0018] In light of the data previously obtained, it would be desirable to complement and update the technical field related to biomass purification and processing, and to develop reliable and reproducible methods for extracting valuable compounds from biomass on an economically viable scale. This can be achieved by utilizing suitable high-temperature extraction methods, in particular steam extraction techniques. Summary of the Invention

[0019] The object of the present invention is to solve or at least alleviate each of the problems resulting from the limitations and disadvantages of the related art. This object is achieved by various embodiments of a method for separating and recovering compounds from biomass, related systems, and applications. Thus, in one aspect of the present invention, there is provided a method for separating and recovering compounds from biomass according to what is set forth in independent claim 1.

[0020] In an embodiment, the method comprises providing a biomass feedstock to an apparatus for processing biomass, thereby forming a reaction zone containing the biomass feedstock; propagating a gaseous extraction fluid through the reaction zone containing the biomass feedstock at predetermined reaction conditions, whereby the target compounds are separated from the essentially solid feedstock material; and recovering the separated target compounds exiting the reaction zone, wherein the extraction fluid advances through the biomass material along the length of the reaction zone, thereby carrying the separated target compounds toward the end of the reaction zone, whereby the collected extract upon recovery is essentially liquid and the target compounds are extracted in fractions, whereby target compounds forming different fractions are eluted at different retention times.

[0021] In an embodiment, the method includes heating and optionally pressurizing the extraction fluid in a first heat transfer unit prior to directing the extraction fluid to the reaction zone, where the extraction fluid is vaporized to form a gas phase. In the method, prior to forming the gas phase, the extraction fluid is an aqueous solution, optionally water.

[0022] In an embodiment, the biomass feedstock is cellulose-containing biomass, particularly lignocellulosic biomass and / or animal-derived biomass.

[0023] In embodiments, the extraction fluid is directed to the reaction zone continuously or in pulses.

[0024] In an embodiment, the reaction conditions include adjusting the temperature in the reaction zone to a range of 100 to 220° C., preferably 150 to 210° C. In an embodiment, the reaction conditions include adjusting the pressure in the reaction zone to a range of about 0.3 MPa to about 3 MPa, preferably about 1 MPa to about 2 MPa.

[0025] In embodiments, the flow of extraction fluid through the reaction zone is adjusted so that the residence time spent by the separated target compounds in the reaction zone is in the range of about 2 minutes to about 30 minutes, preferably in the range of about 5 minutes to about 15 minutes.

[0026] In an embodiment, recovering the target compound exiting the reaction zone includes cooling the extraction fluid carrying the target compound in a second heat transfer unit located downstream of the reaction zone, thereby producing an essentially liquid extract enriched in the target compound.

[0027] In an embodiment, the amount of extraction fluid for recovering the target compounds is about 0.1-10% by volume, preferably about 0.5-2% by volume, of the biomass feedstock fed into the reaction zone, the volume of extraction fluid being calculated according to its liquid state.

[0028] In one embodiment, the dry matter content in the essentially liquid extract collected upon harvesting and containing the target compound is in the range of about 5% to about 30% by weight.

[0029] In embodiments, the biomass feedstock is pretreated with a pretreatment fluid to recover at least volatile compounds prior to extraction with the extraction fluid, the pretreatment occurring at a temperature in the range of 70-120° C. and a pressure in the range of about 0.05 mPa to about 0.5 MPa. In embodiments, the pretreatment fluid is a gaseous substance such as steam or gas.

[0030] In embodiments, the reaction zone is formed within an apparatus for processing biomass configured as a batch reactor, a continuous flow reactor, or a combination thereof.

[0031] In embodiments, the target compounds are selected from the group consisting of cellulose, hemicellulose, lignin, sugars, proteins, and low molecular weight extractive compounds such as terpenoids, phenolic compounds, fatty acids, and resin acids.

[0032] In an embodiment, the target compound is essentially intact long-chain hemicellulose.

[0033] In another aspect, there is provided a system for separating and recovering compounds from biomass according to what is claimed in independent claim 17.

[0034] In an embodiment, the system comprises an apparatus for processing biomass by a reaction chamber containing a biomass feedstock, thereby forming a reaction zone; means for directing a gaseous extraction fluid into the reaction chamber, whereby the extraction fluid propagates through the reaction zone, separating target compounds from the essentially solid feedstock material, and advances through the biomass material, with the aqueous extraction fluid carrying the thus separated target compounds towards the end of the reaction zone; a first heat transfer unit, in which the extraction fluid is heated and optionally pressurized to form a gaseous phase before entering the reaction chamber; a second heat transfer unit, in which the extraction fluid exiting the reaction zone is condensed to produce an essentially liquid extract enriched in the target compound; and at least one control device for adjusting the reaction conditions in the reaction chamber, wherein the system is configured to extract the target compound in fractions, such that target compounds forming different fractions are eluted at different retention times.

[0035] In a further aspect, in accordance with independent claim 18, there is provided a method for separating and recovering essentially intact hemicellulose compounds from lignocellulosic biomass.

[0036] In an embodiment, the method includes providing a lignocellulosic biomass feedstock to an apparatus for processing biomass, thereby forming a reaction zone containing the biomass feedstock; propagating water vapor as an extraction fluid through the reaction zone containing the biomass feedstock at predetermined reaction conditions, whereby hemicellulose compounds are separated from the essentially solid feedstock material; and recovering the separated intact hemicellulose compounds exiting the reaction zone, whereby the aqueous extraction fluid advances through the biomass material along the length of the reaction zone, carrying the separated hemicellulose compounds toward the end of the reaction zone, whereby the collected extract is essentially liquid upon recovery, wherein the recovered hemicellulose compounds are intact hemicelluloses, and the hemicellulose compounds are extracted in fractions, whereby the intact hemicellulose compounds and their degradation products forming different fractions are eluted at different retention times.

[0037] In an embodiment, the method includes adjusting the temperature in the reaction zone to a range of about 160-220°C and adjusting the pressure in the reaction zone to a range of about 0.6-2.5 MPa, thereby obtaining a fraction that accounts for 80-95% of the total amount of intact hemicellulose compounds.

[0038] The usefulness of the present invention arises for a variety of reasons depending on each particular embodiment thereof. One of the major advantages offered by the methods presented herein is the production of essentially intact, uncleaved polysaccharide polymers, such as hemicellulose.

[0039] The extract obtained by the method described herein has a high solids content (5-30% by weight). The pure extract can be used as a food additive, such as a sweetener or thickener, for example, as a feed additive or dispersing agent, providing a functional and low-energy replacement for, for example, starch or gelatin.

[0040] High-quality long-chain polysaccharides such as hemicellulose can be further utilized in the paint and cosmetic industries in the form of a solution or dispersion. This method is highly suitable for producing a ready-to-use extract that does not require further concentration and / or purification. Nevertheless, the pure extract can be subjected to biotechnological post-purification, such as polymerization, to produce a substitute for petroleum-derived plastics, and hydrolyzed into sugars, which can then be fermented into biofuels. The pure extract can be used as a starting product for the needs of the food and / or chemical industries.

[0041] After extraction of specific target compounds, such as hemicellulose, from the biomass material, the residue / pulp remaining in the extraction chamber can be further processed at higher temperatures and / or in the presence of selected chemicals to defibrate the cellulose bundles. This process can be assisted by mechanical refining, for example, by conventional grinding or steam explosion techniques. After removal of the hemicellulose species, the pulp is highly grindable and compressible. Therefore, after removal of hemicellulose from the biomass feedstock, the remaining pulp can be further used to produce cellulose and / or dissolving pulp.

[0042] The disclosed method thereby allows for the isolation of hemicellulose species from biomass that remain in black liquor in conventional pulping techniques. The invention is therefore particularly useful for applications within the paper, energy, food and (animal) feed industries. Furthermore, the invention can be used to process side streams generated in the production of edible oils and grains.

[0043] The present invention further aims to improve the energy efficiency and cost-effectiveness of isolating valuable compounds from lignocellulosic biomass. Compared to traditional liquid extraction, the method presented by the present invention uses less water and can be completed in a much shorter time. Furthermore, this method enables the production of target compounds with high yield and selectivity. Clean steam can be further extracted from the system and reused, further improving the energy efficiency of the process.

[0044] The short processing time eliminates or at least minimizes the formation of toxic compounds that are unavoidable in, for example, steam explosion, and therefore minimizes the amount of lignin in the hemicellulose fraction, allowing the isolation of pure hemicellulose.

[0045] The method described herein is flexibly applicable to various reactor types and designs. The method can be carried out in batch and continuous flow systems, with or without mixing devices (such as screws). Due to its versatility and low water consumption, investment costs associated with the associated equipment can be kept modest. The method is fully scalable and can be used in industrial-scale extraction equipment (e.g., 5-1000 m). 3 ) can be reliably implemented.

[0046] As used herein, the terms "upstream" and "downstream" are used to indicate the order of elements relative to one another, whereby the term "upstream" indicates a location before some particular element or facility, and the term "downstream" indicates a location after some particular element or facility.

[0047] The phrase "a number of" as used herein refers to any positive integer starting from 1, e.g., 1, 2, or 3. The phrase "a plurality of" as used herein refers to any positive integer starting from 2, e.g., 2, 3, 4.

[0048] Different embodiments of the invention will become apparent by consideration of the detailed description. [Brief explanation of the drawings]

[0049] [Figure 1] FIG. 1 is a graph illustrating an exemplary installation for the separation and recovery of target compounds from biomass feedstocks according to the methods of the present invention. [Figure 2] 2A and 2B are graphs showing the total amount of hemicellulose carbohydrates contained in the extracted product and residual biomass obtained by the method of the present invention, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0050] The present invention, in one aspect, relates to a method for separating and recovering compounds from biomass.

[0051] The term "biomass" as used herein refers to any type of organic biodegradable raw material. The methods described herein are particularly useful for processing cellulose-based and / or cellulose-derived biomass, such as lignocellulosic biomass. Lignocellulosic biomass derived from wood and non-wood feedstocks contains cellulose, hemicellulose, and lignin as its primary components, as well as a series of individual compounds collectively referred to as extractives. The latter are primarily composed of components classified as secondary metabolites, such as terpenes and terpenoids, alkaloids, and phenolic compounds. In plant-derived biomass, cellulose is embedded in a matrix of lignin and hemicellulose. Together, they form fiber bundles, a densely packed cellular structure (fiber) that forms the basis of biomass organization.

[0052] Suitable feedstocks include lignocellulosic, i.e., plant-based and / or plant-derived biomass obtained from annual and perennial plants (cereals such as wheat, barley, oats, rye, corn, rice, etc., hemp, flax, etc.), forest, marsh, and field vegetation, associated by-products (bagasse, grain bran, rice husks, straw), and products derived therefrom. Additionally or alternatively, feedstocks can include by-products of forestry (e.g., bark, wood chips, sawdust, and pulp), agriculture (biomass from farming, animal and poultry raising), and / or biowaste.

[0053] The biomass feedstock can have an initial moisture content ranging from 10 to 75 volume percent (vol%). Initial moisture content refers to the moisture content (here, water) of the harvested biomass loaded into the extraction tank. Fresh or pre-dried (e.g., air-dried) biomass can be utilized.

[0054] In this method, a biomass feedstock is provided to an apparatus 10 for processing biomass (FIG. 1). Various reactor configurations can be adapted (discussed further below). Providing the biomass feedstock to the apparatus 10 forms a reaction zone 10A, where separation of target compounds from essentially solid materials occurs. The reaction zone 10A is typically established within a reaction chamber of the apparatus 10.

[0055] Extraction products, referred to herein as target compounds, include, but are not limited to, for example, polymeric carbohydrates, such as the polysaccharide polymer cellulose and hemicellulose(s), lignin, simple carbohydrates (sugars), such as glucose, mannose, and galactose, but also include, for example, proteins, fats, waxes, and low molecular weight extractive compounds, such as terpenes and terpenoids, phenolic compounds, fatty acids, resin acids, and the like.

[0056] This method has proven particularly efficient in the isolation and recovery of essentially intact, uncleaved, and / or unaltered compounds. Long-chain (unaltered) target compounds, such as carbohydrate polymers, can be reliably produced. In the research underlying the present invention, the inventors surprisingly demonstrated that essentially intact long-chain molecules, such as hemicellulose, can be extracted from lignocellulosic materials with very high yields and purity. The target compounds obtained upon extraction are sufficiently pure to be used in a variety of useful applications, such as the food industry (food or animal feed production), essentially without further purification. The resulting compounds, when further modified via chemical and / or biotechnological processes, can be utilized, for example, in the polymer industry as biodegradable alternatives to plastics or for the production of biofuels.

[0057] Separation of target compound(s) occurs upon propagating extraction fluid 1 through reaction zone 10A containing biomass feedstock. By appropriately designing the reactor apparatus and / or reaction chamber (extraction tank) and by establishing specific reaction conditions (temperature, pressure, extraction fluid flow rate, etc.) in the reaction / extraction zone, pre-selected target compound(s) can be extracted (i.e., separated and collected) from the feed biomass with high yield (5-30 wt% dry matter content in the extracted sample) and high recovery (approximately 90% of target compound collectable in a single run).

[0058] The extraction procedure is carried out using an aqueous fluid as the extractant. The aqueous fluid is typically provided as a liquid (i.e., normally present in a liquid state) and converted to a gaseous substance before entering the reaction zone. In a preferred implementation, the extraction fluid is water. Before entering the reaction zone, the water is vaporized to form a gas phase (i.e., in this disclosure, "aqueous vapor" is also referred to as water vapor). The formation of the gas phase is achieved by (pre)heating and optionally pressurizing the liquid extractant in a first heat transfer unit 9. The first heat transfer unit 9 can be configured as a heat exchanger or as a heater (vaporizer) device located upstream of the reaction zone / reaction chamber 10A.

[0059] To avoid confusion, in this disclosure, the term "phase" (of matter) is used synonymously with the term "state" (of matter) unless explicitly defined otherwise. The term "steam" is used interchangeably with the terms "aqueous vapor" or "water vapor." For clarity, it is assumed that both water vapor and steam represent gaseous (gas) phases. In some cases, the term "vapor" also refers to the gaseous phase of an aqueous or non-aqueous solution containing water or other organic solutions as a solvent. The terms "gas phase" or "vapor" are used to refer to a state of matter (e.g., vapor) unless otherwise specified. Gases as distinct elements consisting of single gas particles (e.g., molecules and atoms such as O2, N2, CO2, etc.) and existing in a gaseous state at room temperature are generally referred to as "gases."

[0060] The method of the present invention primarily utilizes concepts from column chromatography. Thus, separation of target compounds follows the principles of column chromatography. The biomass material provided to the reaction zone / reaction chamber 10A forms the stationary phase or matrix, and the extraction fluid forms the mobile phase (eluent). The extraction fluid enters the reaction zone 10A through one or more inlets (not shown) and travels through the biomass material along the length of the reaction zone. Due to the advancement of the gas-phase extraction fluid through the reaction zone, under certain reaction conditions, the target compound(s) separate from the essentially solid biomass material and travel toward the end of the reaction zone, using the extraction fluid as a carrier.

[0061] Thus, water vapor propagates through the reaction zone 10A containing the biomass material under high temperature and pressure, releasing extractable substances contained in the plant cells into a carrier medium (also known as an extraction fluid, here water vapor). The target compounds released / separated from the essentially solid matrix enter a mobile phase (extraction fluid), which carries the target compounds toward the end of the reaction zone, subsequently recovering the target compound(s) as they exit the reaction zone.

[0062] Recovery of the target compound(s) can be performed in a second heat transfer unit 11, within which the extraction fluid containing the target compounds undergoes cooling and / or condensation, so that the collected extract 2 upon recovery is essentially liquid. In such cases, recovery of the target compound(s) occurs outside of the reaction region 10A.

[0063] During the extraction process, the target compounds transition from an essentially insoluble state (forming the plant cell wall) to an essentially soluble or dissolved state. As an example, typically insoluble hemicellulose becomes soluble when steam is passed through reaction zone 10A in the manner described above under reaction conditions involving high temperature and pressure.

[0064] The target compound(s) transferred to the extraction fluid by dissolution or dispersion travels towards the recovery site 11 together with the liquid (water) droplets contained in the water vapor and / or the liquid released from the vacuoles of the plant cells. Depending on the reaction conditions, a target compound-rich fluid obtained at the outlet of the reaction zone 10A may form an essentially gaseous phase, such as unsaturated or saturated vapor. Recovery of the compounds carried by the fluid(s) takes place in a second heat transfer unit 11 configured as a cooling device 11.

[0065] Other compounds can be extracted in a similar manner. Some target compounds are not water-soluble and can be transported toward the collection site in the form of colloidal droplets dispersed in the vapor phase. Upon further condensation (11), the extract becomes liquid. The liquid fraction thus obtained contains the target compound(s) dissolved or dispersed in the liquid medium.

[0066] To produce a high-quality product, the reaction conditions in the reaction zone / chamber 10A are set as follows: The temperature in the reaction zone 10A is adjusted and maintained within a range of about 100 to 250°C (degrees Celsius), preferably 100 to 220°C, and more preferably 150 to 210°C, and the pressure is adjusted and maintained within a range of 0.1 MPa to about 4 MPa (1 to 40 bar); preferably, about 0.3 MPa to about 3 MPa (3 to 30 bar). In some cases, more preferred ranges include about 0.6 MPa to about 2.5 MPa (6 to 25 bar), and even more preferably, about 1 MPa to about 2 MPa (10 to 20 bar). In some cases, the extraction conditions can be adjusted to include temperatures below 100°C, particularly temperatures in the range of about 80 to 100°C. The temperature can be held stable or increased during the process.

[0067] A reaction temperature of about 220°C generally corresponds to a pressure of 2.3 MPa (23 bar). Higher temperatures, for example, up to or even above 250°C, can also be employed. Saturated steam superheated to about 250°C can be produced at a pressure of about 4 MPa (40 bar).

[0068] When saturated steam is used as the extraction fluid, the pressure in the reaction zone established by the steam generally follows the following non-limiting examples: about 0.1 MPa (101 kPa or 1 bar) at about 100° C.; about 0.476 MPa (4.8 bar) at about 150° C.; and about 1,555 MPa (15.6 bar) at 200° C. Generally, at a temperature of about 210° C., a pressure within the range of about 0.1 MPa to 2 MPa (1 to 20 bar) can be established and maintained.

[0069] In some configurations, considering factors such as reactor design, heat losses, and condensation during the reaction, the initial vapor pressure of the reactor can generally be low, approximately 1-1.5 MPa at approximately 200°C. Meanwhile, the water vapor pressure at the outlet depends on the packing density, and the outlet temperature of a densely packed reactor can be 50°C lower than the inlet (pressure is approximately 0.5 MPa, temperature is approximately 150°C, or even lower if the outlet port is clogged). Under dynamic flow (continuous flow) conditions, a dynamic equilibrium can be established for at least the pressure and temperature parameters. In this case, extraction / fractionation can be performed in several collection runs.

[0070] Specifically, the pressure differential(s) between the material to be extracted and the extraction matrix (biomass) cause the extraction / fractionation of the target compound by enabling or at least facilitating the migration of the target compound through the reaction region matrix. Thus, in some cases, a preferred water vapor pressure range is from about 0.3 MPa to about 3 MPa.

[0071] The above-mentioned parameters are established in the reaction zone 10A by directing an extraction fluid having the desired temperature / pressure into the reaction chamber. Medium-pressure (0.45-1.6 MPa) or high-pressure steam (greater than 2 MPa) generated in the first heat transfer unit 9 can be directed to the reaction zone. Thus, the first heat transfer unit 9 can be configured as, for example, a low-pressure, medium-pressure, and / or high-pressure steam generator or boiler.

[0072] Rapid release of target compounds from solid components can be achieved by passing medium- or high-pressure steam through the biomass material contained in the reaction zone 10A. The residence time of the target compound is defined as the time the released / separated target compound spends in the reaction zone (hot area). The residence time is short, typically in the range of about 2 to 30 minutes, preferably about 5 to 20 minutes, and more preferably about 5 to 15 minutes. Because the target component is rapidly released from the stationary phase, the residence time essentially defines the reaction time during which the preselected target compound elutes from the reaction zone. Depending on the reaction conditions, extraction solvent flow rate, and / or reactor capacity (volume, configuration, horizontal / vertical position), reaction times as short as 2, 5, 10, 15, or 20 minutes, as well as intermediate and intermediate times, can be achieved.

[0073] Short residence times are important for obtaining high-quality products, especially when processing at high temperatures, e.g., above 200°C. Maintaining short residence times is crucial for extracting essentially intact long-chain polymeric compounds, such as hemicellulose. Therefore, the method described herein enables the extraction of essentially intact long-chain hemicelluloses, each containing approximately 500 to 3,000 monosaccharide units. Other polymers and / or molecular clusters can also be extracted using similar methods.

[0074] Short treatment times further prevent uncontrolled degradation (optionally catalytic hydrolysis or autolysis) and / or chemical modification of target compounds, especially polymer molecules, and prevent the formation of toxic and / or inhibitory compounds that are typically formed upon (partial) degradation of hemicellulose. Furthermore, reducing treatment times to a few minutes prevents thermal degradation (combustion) of the biomass feedstock.

[0075] As described above, this method follows the concept of column chromatography. Therefore, this method allows target compounds to be eluted in fractions. The separated and recovered compounds, referred to as target compounds, are shown as C1 and C2 in Figure 1. This method therefore allows for the separation of non-identical compounds C1 and C2 (see the exemplary pentagon and circle) from the essentially solid material forming the stationary phase (also known as biomass) and the separate extraction of each of these compounds with high purity. Alternatively, the extraction conditions can be adjusted to allow for the separation and extraction of both compounds C1 and C2 together. Therefore, the resulting extract 2 contains compounds C1 and / or C2 in high recovery (80-95%) and is essentially free of any impurities.

[0076] The liquid extract 2 that can be obtained upon harvesting and that contains the target compound(s) has a dry matter content (solids content) in the range of about 5% to about 30% by weight.

[0077] Reaction parameters, eluent / extraction solvent flow rates, and instrument-related parameters can be adjusted to allow different target compounds to elute in separate fractions with different retention times. The latter generally means that non-identical target compounds have different residence times in the reaction zone. For example, under certain reaction conditions, a fraction containing compound C1, such as intact hemicellulose, elutes 2–5 minutes after the extraction fluid is directed into reaction region 10A. A fraction containing compound C2, such as low-molecular-weight carbohydrates resulting from the degradation of hemicellulose (monosaccharides, disaccharides, and oligosaccharides, and their mixtures), elutes 7–8 minutes after the start of the reaction. Similarly, multiple target compounds can be separated in a single run.

[0078] The amount of extraction fluid required to obtain a fraction enriched in the target compound(s) typically comprises about 0.1-10% by volume, preferably about 0.5-2% by volume, of the biomass feedstock brought into the reaction zone. The volume of water extraction fluid is calculated depending on the liquid state of the extraction fluid. Therefore, although extraction fluids such as water become gaseous (in steam form) as they propagate through the reaction zone, the amount of water required to recover the target compound(s) is calculated based on their liquid state.

[0079] When water is used as the extractant, the pH of the system is generally maintained at neutral (pH 7). Without specific adjustments, the pH of pressurized water tends to be below neutral and acidic (pH 3-4). If the system is optionally supplied with chemical extractant(s) to aid recovery, the pH of the system can vary within the range of 1-14.

[0080] The method is largely based on heat transfer between a mobile phase (an extraction fluid, such as steam, propagating through the reactor) and a stationary phase (a biomass matrix). In this process, heat is transferred from the extraction fluid to an essentially "cold" matrix at the interface between an essentially gaseous (e.g., steam) and an essentially solid phase. Therefore, the larger the area created / occupied by this interface, the more efficient the energy (heat) transfer between the phases. Reaction and / or residence time can be adjusted by providing a biomass matrix with a predetermined particle size, optionally with a predetermined particle size distribution. In some cases, chopped or finely ground biomass with a particle size of about 0.1 cm to 10 cm, preferably about 0.5 cm to 5 cm, can be advantageous, as it increases the surface area available for reaction and enlarges the heat transfer interface.

[0081] Particle size further influences packing density. In practice, reaction zone 10A can be configured to include one or more (sub)zones containing particles of different sizes and / or origins (i.e., from different biomass feedstocks). These (sub)zones allow the eluent / steam pressure to be adjusted throughout the reaction zone.

[0082] Exemplary packing densities are about 5 to 150 g / dm 3 or may vary within a larger range.

[0083] As mentioned above, the apparatus / reaction chamber acts as a heat transfer unit in which thermal energy / heat is transferred from the mobile phase to the stationary phase. When saturated (aqueous) vapor (i.e., water vapor) is present in the heat transfer / heat exchange, this vapor actually condenses immediately on the cooler surface of the heat transfer unit (biomass matrix) where the temperature is lower than the vapor's condensation temperature. Thus, a thin condensation film forms on the matrix surface through which heat must pass, establishing resistance. This resistance coefficient must be taken into account when designing reaction parameters such as temperature, pressure, and matrix packing density. Under certain conditions, including at least a given combination of pressure and temperature, a concentrated liquid film is established on the surface of the biomass matrix, which can aid in the propagation of the separated target compounds through the reaction zone (biomass matrix).

[0084] In this method, the feedstock biomass can be further pretreated in a pretreatment step distinct from the extraction step described above. Feedstock pretreatment can occur in apparatus 10 or in a separate reaction vessel (not shown). In apparatus 10, pretreatment can be carried out in reaction zone 10A or in a separate pretreatment zone (not shown) that can be physically and / or functionally separated from reaction zone 10A.

[0085] The pretreatment step, which precedes the extraction step, aims to remove and / or recover at least volatile compounds from the biomass feedstock. Volatile compounds include volatile organic compounds (VOCs), such as various aromatic compounds, nitrogen oxides (N x O y) and / or other vaporizable compounds. Additionally or alternatively, various compounds (e.g., silicates) that prevent and / or interfere with extraction can be removed during the pretreatment step. The key function of pretreatment is to (pre)heat the raw material and induce swelling with an extraction fluid, such as steam, that allows for a more rapid and accurate extraction reaction. During pretreatment, the biomass feed is treated with a pretreatment fluid under reaction conditions that include low or atmospheric pressure and generally at a reaction temperature lower than that used during extraction. In this method, these conditions include adjusting the pretreatment temperature to a range of about 100°C to about 120°C and adjusting the pretreatment pressure to a range of about 0.05 mPa to about 0.5 MPa (0.5 to 5 bar). Optionally, the pretreatment step can be carried out in the absence of excess pressure / atmospheric pressure at low temperatures (about 70 to 100°C, particularly 70 to 90°C).

[0086] In pretreatment, a gaseous substance is used as a pretreatment fluid to wash the biomass feedstock. The gas phase can be generated from a suitable solvent, such as water or an aqueous solution of an alcohol (e.g., ethanol), an acid, or an alkali, to produce steam. Alternatively, gaseous substances such as carbon dioxide, ammonia, or sulfur dioxide can be utilized. The pretreatment step can be carried out, for example, in an open reactor with steam purification at atmospheric pressure, or in a closed / sealed reactor (gas purification, optionally pressurized).

[0087] In another aspect, the present invention relates to a system for separating and recovering compounds from biomass. FIG. 1 illustrates, at 100, the concept underlying an embodiment of the system and its apparatus. The system 100 includes an apparatus 10 for processing biomass, having a reaction chamber (extraction chamber) configured as a tank or vessel containing biomass feedstock. A reaction zone 10A is established within the reaction chamber. Thus, in this disclosure, the term "reaction zone" generally refers to the reaction chamber, and vice versa.

[0088] The design and shape of the reaction chamber, particularly the ratio between the chamber's height / length and its cross-sectional area (or diameter), are adjusted to enable or assist in achieving relatively short reaction / residence times and rapid elution of target compounds from the reaction chamber. The above-mentioned parameters are typically adjusted taking into account the reaction conditions to be established within the device 10 to achieve the elution of target compound(s) in various desired combinations in the most efficient manner (different desired compounds / different groups of desired compounds eluted in fractions).

[0089] The stated ratio between the height / length and cross-sectional area (or diameter) of a reaction chamber defines its shape factor. Depending on the reaction temperature and desired product, the shape factor can be adjusted within a range of about 1:1 to about 10:1. Examples include obtaining reaction chambers with shape factors of 2:1, 3:1, 4:1, 5:1, or 6:1. When designing a reactor with a specific shape factor, care should be taken to avoid excessively long residence times (of the target compound) (to avoid thermal degradation) and to ensure that the eluent flow is essentially laminar.

[0090] Overall, at least two important issues must be considered when designing a reaction chamber for the apparatus 10. The chamber must be free of so-called blind or dead corners (e.g., those formed at the junction between flat lids or top covers and / or that restrict fluid flow through the chamber). The presence of dead corners slows elution, resulting in thermal and / or (bio)chemical degradation of the target compound (eluate), resulting in reduced product quality. Furthermore, degradation processes occurring in the extraction zone can cause blockages between the matrix and the reactor. Furthermore, the shape of the chamber should be essentially tubular. Tubular tanks can have the same or different cross-sections throughout the tube. A cylindrical extraction chamber (a tank with a constant cross-sectional area throughout its length) is preferred. This allows for uniform distribution of the generated extraction fluid, such as water vapor, throughout the reaction region and allows the extraction fluid to propagate along the length / height of the chamber with an essentially uniform velocity at the leading edge.

[0091] The device 10 comprises means for directing an extraction fluid into the reaction chamber (indicated by the "in" arrow in FIG. 1 ) and means for withdrawing the extraction fluid enriched in the target compound(s) from the reaction chamber (indicated by the "out" arrow). The extraction fluid can be directed into the reaction region through a suitable inlet port, for example configured as an injection port. Suitable outlet ports can therefore be located at the ends of the reaction zone. The inlets and outlets are preferably equipped with appropriate regulators, such as valves. The device 10 can be equipped with several inlet and / or outlet ports, optionally provided in the end plates of the device.

[0092] The system 100 further comprises a first heat transfer unit 9 in which an extraction fluid 1, such as water, is (pre)heated and optionally pressurized to form a gas phase. The first heat transfer unit is arranged to vaporize liquid arriving thereat via a source vessel (e.g., a water vessel), and the resulting (pressurized) water vapor is directed to the reaction chamber. The first heat transfer unit 9 may be configured as a heat exchanger, steam generator, or boiler, as described above.

[0093] Additionally or alternatively, the extraction apparatus 10 may be placed within an external chamber (not shown) that acts as a heating jacket, whereby a stream of heating medium is generated around the apparatus 10 (between the inner wall(s) of the external chamber and the outer wall(s) of the apparatus 10) to enable or enhance heat transfer. The heating medium may be the same as the eluent, e.g., steam. Providing such a "double chamber" allows for efficient steam and heat recovery and recycling.

[0094] The system 100 further comprises at least one device in which the target compound(s) C1, C2 exiting the reaction zone 10A are collected. Such a device may be provided as a (second) heat transfer unit 11 arranged downstream of the reaction zone 10A. In the heat transfer unit 11, the extraction fluid exiting the reaction zone 10A is cooled / condensed to produce an essentially liquid extract 2 enriched in the target compounds. The heat transfer unit 11 may be configured as a heat exchanger with a condenser function. The product 2 enriched in the target compound(s) is further collected in a collection device 13, configured for example as a suitable container or an automatic fraction collection chamber.

[0095] The first and second heat transfer units 9, 11 can be combined into an integrated heat transfer / heat exchanger solution (not shown). Whether implemented as separate devices or as an integrated heat exchanger assembly, the system can be configured to (re)use the thermal energy released upon cooling the extraction fluid in the second heat transfer unit 11. The heat released upon cooling can be recycled for use, for example, in the heating device 9 and / or can be exhausted for external use.

[0096] In some cases, the reaction conditions are adjusted so that the extraction fluid can be at least partially condensed as it propagates through the reaction zone. In such cases, the product compound-rich fluid obtained at the outlet of the reaction region is provided in an essentially liquid, flowable phase and can be collected and used as is or transferred for further condensation / concentration, for example in device 11 or other equipment (not shown).

[0097] The system 100 further comprises at least one pump 14 for the extraction fluid, located upstream of the heat transfer unit 9 and / or upstream of the extraction apparatus 10, and a plurality of control instruments 12, 12A, and associated devices for controlling the reaction conditions in the apparatus 10. The at least one control device 12 (upstream of the apparatus 10) can be configured to regulate the reaction conditions in the reaction chamber, particularly the pressure and temperature in the reaction zone 10A. Separate pressure and temperature control devices can be provided. Flow meters for measuring and / or regulating the flow rates of fluids entering the reaction chamber can be integrated into the device(s) 12 or provided separately. A heat recovery system (not shown) can further be provided to enable heat transfer / exchange between the first and second heat transfer units 9, 11 and / or to recover thermal energy produced in the heat transfer units 9, 11 for external use.

[0098] The pump 14 and / or control device 12 can be configured to direct the extraction fluid to the reaction region 10A continuously or in pulses, with the pulse duration being reactively adjustable.

[0099] The apparatus 10 can be configured as a static (batch) reactor, a dynamic (continuous flow) reactor, or a combination thereof (e.g., a semi-continuous flow system). An exemplary system comprising a vertical batch reactor 10 is shown in FIG. 1. The extraction fluid is directed from top to bottom through a reaction zone 10A. The vertical reactor can be equipped with a reaction chamber that is essentially cylindrical (having the same cross section along the entire length of the chamber), conical or funnel-shaped, or has a more complex design.

[0100] Alternatively, the apparatus 10 can be implemented as a continuous plug flow reactor (not shown). In such cases, the reactor is positioned essentially horizontally, with or without tilt. Possible configurations include screw- or piston-operated continuous flow reactor apparatus. In an exemplary screw reactor-based system, a rotating screw is disposed within the reaction chamber / reaction zone 10A.

[0101] In screw-type continuous flow systems, the optimum reaction time is achieved by adjusting the (rotary) screw speed and / or screw parameters, such as the screw angle (steeper / slighter), helix angle and / or pitch, as well as by adjusting the pressure and / or amount of extraction fluid, such as steam, propagating through the reactor. The extraction fluid preferably propagates in the continuous flow reactor apparatus in a direction opposite to the screw rotation (or piston movement).

[0102] The continuous flow reactor system may further be equipped with a screw press for removing excess liquid. The screw press may be provided in reaction zone 10A or in a separate process stage located downstream of reaction zone 10A. Removal of excess fluid may be performed under pressure, or this stage may be depressurized (e.g., by reducing the screw flight angle or via conventional steam explosion procedures). Depressurization of apparatus 10 is performed only after the desired target compound has been recovered as extract 2, for example, at recovery site 11.

[0103] The methods disclosed above can be advantageously applied to the separation and recovery of essentially intact long-chain hemicellulose compounds from lignocellulosic biomass. Essentially intact long-chain hemicellulose compounds, as used herein, refer to hemicelluloses containing approximately 500 to 3,000 monosaccharide units. In some cases, the methods allow the separation and recovery of hemicelluloses containing approximately 1,500 to 2,000 monosaccharide units. The long-chain, high-molecular-weight nature of the recovered hemicellulose compounds has been determined by light scattering.

[0104] Plant hemicellulose is a mixture of polysaccharides generally defined based on structural characteristics, including xylans (arabinoxylans, glucoronoxylans), mannans (glucomannans, galactomannans), xyloglucans, beta-glucans, and galactans. Thus, the composition of hemicellulose-containing extracts can vary depending on the feedstock. For example, biomass from broadleaf trees and various grasses is rich in xylans, while coniferous trees contain primarily mannans. The methods presented herein are versatile in that they allow for the extraction of long-chain hemicellulose polysaccharides from almost any type of biomass feedstock, particularly lignocellulosic biomass feedstocks.

[0105] In this method, a lignocellulosic biomass feedstock is received in a reaction chamber of an apparatus for processing biomass 10, thereby forming a reaction zone 10A containing the biomass feedstock. Water 1 is directed by a pump 14 to a first heat transfer unit 9, where the water in the heat transfer unit 9 is vaporized under high temperature and pressure to form a gas phase, here steam. The steam, as an extraction fluid, is propagated through the reaction zone containing the biomass material at predetermined reaction conditions that cause the partitioning of hemicellulose compounds from the essentially solid feedstock material. The reaction conditions (temperature, pressure, reaction time, and water flow rate) are adjusted to maintain a negligible amount of lignin separated from the biomass matrix material, thereby obtaining a highly pure hemicellulose product in an unaltered, essentially intact form. The product is collected in a recovery zone 11 as an essentially liquid extract 2. The liquid extract 2 is preferably produced in a (second) heat transfer unit 11, where the hemicellulose-rich steam is cooled / condensed to produce a liquid phase. The recovery of pure long-chain hemicellulose product is 80-95%.

[0106] The reaction conditions include adjusting the temperature in the reaction zone 10A to a range of about 160 to 220 degrees Celsius, and adjusting the pressure in the reaction zone to a range of about 0.6 to 2.5 MPa.

[0107] The process underlying hemicellulose extraction can be summarized as follows: Under conditions of high temperature and pressure, hemicellulose compounds contained in plant cells (lignocellulosic biomass feedstock) become soluble ("liquefied") and migrate into the mobile phase. Water molecules contained in the mobile phase assist the target hemicellulose to propagate through the reaction zone. This transports the hemicellulose in the form of gel-like droplets dispersed in the vapor phase towards the exit of the reaction zone and collection site. In vapor extraction experiments, the processing temperature has proven to be an important controlling factor.

[0108] In multiple experimental trials, elution with steam volumes ranging from approximately 3 / 5 to the full volume of the extraction tank resulted in recovery of over 90% of high-quality product (herein, long-chain hemicelluloses), with solids in the hemicellulose-rich extract ranging from approximately 5-10% by weight. Reaction times were approximately 5-10 minutes. A flow rate of 300 ml / min of extraction fluid proved most beneficial (for a 3 L reaction chamber). Thus, within 4-5 minutes of the start of extraction, over 90% of the total carbohydrates could be isolated and recovered. With a reaction time of approximately 7-8 minutes, the solids content of the extracted carbohydrates exceeded 20% by weight. Analysis of the solid biomass matrix after elution indicated that, in some cases, less than 1% by weight of hemicellulose remained in the matrix.

[0109] Trials were carried out in reaction tanks with volumes of 0.05 L, 1 L and 3 L. The results are summarized in Tables 1 and 2. The Brix value (%) indicates a measure of the sugar content in the solution.

[0110] Trial 1 (Tables 1A, 1B). Steam extraction to produce long-chain hemicellulosic compounds: 40 g sawdust, 50% dry solids (ds) content; elution flow rate 5 ml / min; 200°C; reactor volume 0.05 L. [Table 1]

[0111] Trial 2 (Tables 2A-2D). Steam extraction to produce long-chain hemicellulosic compounds: sawdust ds 42%; pretreatment fluid flow rate 500 ml / min. Reaction parameters: 200 °C; elution flow rate 100-500 ml / min. Trial 2 results show that carbohydrates (sugars) are extracted from fresh biomass samples within minutes of directing steam into the extraction chamber. [Table 2] JPEG2023516488000004.jpg106159

[0112] Experimental trials were performed as follows: An exemplary 3-L tank was preheated at 200°C with steam as the pretreatment fluid, which was directed to the extraction tank at a flow rate of 500 ml / min. After pretreatment, steam as the extraction fluid was directed to the tank at a flow rate of 500 ml / min (first experiment; Table 2A) and 300 ml / min (second experiment; Table 2B). In this disclosure, the flow rate is calculated according to the liquid state of the extraction fluid. Therefore, the flow rate of the extraction fluid in this experiment corresponds to the pumping rate of the feedwater. From Table 2B, it can be observed that in the 3-L tank, at a flow rate of 300 ml / min, approximately 4 / 5 of the total amount of hemicellulose could be recovered in approximately 10 minutes. The residence time of hemicellulose in the extraction tank was approximately 20 minutes from the start of the extraction. The high-quality solids content in the extract thus obtained was approximately 5%, approaching the standard value obtained in an industrially (up)scalable process. Hemicellulose species essentially exhibited a sharp elution region at the beginning of the extraction process and a correspondingly short residence time. Overall, carbohydrate extraction was completed when approximately 6 L (twice the extraction tank volume) of extraction fluid, calculated according to liquid state (i.e., water), had traveled through the reaction zone containing the sample biomass.

[0113] In the experiment with a flow rate of 500 ml / min (Table 2A), the elution region was clearly wider, and similar yields were achieved with an elution volume of about 5 L rather than about 3.3 L (Tables 2A, 2B).

[0114] In both experiments, the extracted products were essentially intact long-chain hemicellulose species. Determination of the molecular weight of the extracted compounds was performed by light scattering.

[0115] The experiments were repeated with a 1 L extraction tank (Tables 2C and 2D). In a similar manner to the above, the tank was preheated with steam as the pretreatment fluid and directed to the extraction tank at 200 °C with a feed pump speed of 500 ml / min. After pretreatment, steam as the extraction fluid was directed to the tank at flow rates of 300 ml / min (first experiment; Table 2C) and 100 ml / min (second experiment; Table 2D). These experiments aimed to keep the residence time short by reducing the size of the extraction tank. The so-called condensate fraction was not collected during extraction in the 1 L tank trials; in contrast, in the 3 L tank trials, the condensate flowed down the reaction zone by gravity or mixed with the extract.

[0116] An extraction fluid flow rate of 300 ml / min proved to be the most beneficial, even with a 1 L extraction tank. A flow rate of 100 ml / min resulted in a good carbohydrate elution profile at the beginning of the extraction. However, the slow rate, plus the high temperature (200 °C), caused the sample to be damaged by thermal degradation (combustion). Furthermore, this flow rate resulted in a broad elution region.

[0117] Residence time (the time the separated hemicellulose spends in the extraction (hot) zone) also affects the quality of the hemicellulose species. As an example, the 1 L extraction tank described above was implemented as a cylinder with a height / length of 160 mm and a diameter of 88 mm (height:diameter factor = 160:88 = 1.8). This configuration worked well at high extraction fluid flow rates (300 ml / min), but at slower flow rates (100 ml / min), the sample began to "burn" (Tables 2C and 2D). In contrast to residence time, the geometry of the extraction vessel, while important, was not critical to product yield and / or quality. Experiments established that the method disclosed herein, utilizing steam as the extraction fluid, operates viably over a fairly wide geometric range. In continuous-flow processes, the geometry of the extraction vessel is more important than in batch processes. In either case, the geometry of the extraction vessel must be designed with the desired / required product in mind. Product characteristics such as quality (e.g., decomposition degree), yield, concentration, and recovery rate can be influenced to some extent by reaction conditions, but an improperly designed extraction chamber can eliminate the advantages offered by steam extraction.

[0118] The above results clearly demonstrate that steam treatment is an efficient tool for fractionating biomass components. The extraction process can be completed in approximately 10 minutes or more, regardless of whether high-quality product production is desired. Chromatographic steam elution allows for the separation and isolation of the purest fraction of hemicellulose species. Therefore, this method allows for the production of extracts with solids contents of approximately 5-6% by weight and good shelf life. Steam extraction as described herein saves water, energy, and time compared to traditional hot water extraction methods.

[0119] Several additional experimental trials were conducted to estimate the effect(s) of reaction- and setup-related parameters on the separation of target hemicellulosic compounds from biomass by steam extraction. Untreated straw was used as the reference material (labeled "straw"; Figure 2B). The reaction time was 15 min, and samples were collected at 3-min intervals, resulting in five samples from each extraction. The trials included different temperature ranges. That is, the reaction temperatures were selected separately within the range of approximately 160-165 °C, approximately 180-185 °C, and approximately 195-200 °C.

[0120] The same extraction series (three different temperatures, i.e., 160 °C, 180 °C, and 200 °C; reaction time 15 min; five extraction samples) was performed on (chopped) straw biomass fractions with the following straw lengths: 1) 0.2–0.5 cm (denoted by the Latin letter “L,” see Figures 2A, 2B) and 2) 1.5–2 cm (“P”). Packing density 200 g / dm 3 ("V") and 300g / dm 3 ("T") was used.

[0121] The optimum packing density from the viewpoint of energy consumption is approximately 100 to 350 g / dm 3 Includes values ​​in the range.

[0122] The experiments were carried out in a laboratory-scale extraction tank equipped with a 6 ml extraction chamber. The tank was essentially cylindrical in shape. The biomass material was pretreated by (water) steam propagating through the reaction chamber while simultaneously heating it to achieve the packing densities shown above. Higher packing densities (300 g / dm 3 The extraction ratios for chambers with lower packing densities (200 g / dm 3The extraction ratios for the chambers with the elution fluid were 2:1, 4:1, and 6:1. The extraction ratio is calculated according to the liquid state and is defined as the total volume of extraction fluid used during extraction relative to the volume of the reaction chamber. In this example, the extraction fluid was steam. The eluted product (hemicellulose-rich liquid extract) and the solid residual fraction (so-called non-extracted biomass) were analyzed to determine the amount of carbohydrate (sugar) compounds therein. The results are therefore summarized in Figures 2A and 2B.

[0123] Figure 2A is a graph showing the total amount of hemicellulose sugar compounds measured in the liquid hemicellulose-rich extract(s) obtained during the steam extraction series described above. The graph shows the amount of hemicellulose product (mg) extracted per gram of (steamed) straw biomass. Figure 2B is a graph showing the total amount of hemicellulose sugar compounds (mg / g) in the solid residual biomass after the series of extractions.

[0124] The abbreviations used to identify the samples are generally explained above. For example, the leftmost sample labeled "160T1L" is a sample of short straw (0.2-0.5 cm), 160°C, and densely packed (300 g / dm 3 ) indicates that the extraction was carried out in a reaction chamber with an extraction ratio of 1:1. The rightmost sample marked "200V6P" refers to an extraction process carried out in a reaction chamber filled with long straw (1.5-2 cm), at 200 °C, and with a low density (200 g / dm3) at an extraction ratio of 6:1.

[0125] Hemicellulose sugar compounds measured in the extract fractions included mannose (Man), galactose (Gal), xylose (Xyl), arabinose (Ara), rhamnose (Rha), glucuronic acid (GlcA), galacturonic acid (GalA), and 4-O-methylglucuronic acid (4-O-Me-GlcA).

[0126] The results in Figures 2A and 2B show that an extraction temperature of 200°C results in a greater amount of eluted hemicellulose compounds. For example, Figure 2B shows that the amount of hemicellulose sugars in the solid phase (steamed straw) decreases with increasing extraction temperature, while the situation is reversed in the liquid product (Figure 2A).

[0127] Referring again to FIG. 2B, at 160°C, the cellulose was densely packed (T; 300 g / dm 3 At 180°C, higher extraction ratios were observed in densely packed columns at conditions including extraction ratios of 2:1 (long straw matrix, see sample 180T2P) and 3:1 (short straw matrix, see sample 180T3L). The lower extraction ratios were observed in the less densely packed columns (V; 200 g / dm 3 At medium temperatures (180°C), higher extraction ratios were observed for the short straw matrix compared to the long straw matrix. At 200°C, slightly higher amounts of hemicellulosic compounds were observed even in the densely packed column (T).

[0128] However, the results in Figure 2A show that the concentration of hemicellulose compounds appears to be higher in samples collected from the less densely packed reaction chambers when measured directly from samples containing hemicellulose-rich (liquid) extracts. Extracts obtained from short straw matrices contained, on average, more hemicellulose sugars than extracts obtained from long straw matrices.

[0129] The results in Figures 2A and 2B clearly demonstrate that the yield of hemicellulosic compounds can be efficiently regulated by adjusting the reaction and setup related parameters.

[0130] To determine the sugar content of untreated biomass compared to steam-treated biomass, trials were expanded to a 3 L extraction tank with the following extraction conditions: 200 °C, a packing density of 200 g / dm3, and an extraction ratio of 2:1. Values ​​marked with a "less than" symbol ("<") refer to concentrations below the decision threshold. The results are summarized in Table 3. [Table 3]

[0131] In the untreated straw matrix, the total carbohydrate content was 72.8%, which essentially corresponds to the total carbohydrate content in the steam-treated matrix (73.4%). However, the glucose (Glu) portion of the total carbohydrate content in the steam-treated matrix increased from 76.3% to 93.6%, while the xylose (Xyl) portion decreased from 21.7% to approximately 5.9%. This result clearly indicates that leaching of hemicellulosic compounds (reduction of xylose sugars) occurred, and the remaining carbohydrates were primarily glucose sugar units derived from cellulose.

[0132] It will be apparent to those skilled in the art that the inventive concept is intended to encompass various modifications of the basic embodiment disclosed herein. It is understood that the examples set forth above are illustrative of various embodiments of the present invention and should not be construed as limiting with respect to the scope of the appended claims.

Claims

1. 1. A method for separating and recovering compounds from biomass, comprising: - providing a biomass feedstock in an apparatus (10) for processing biomass, thereby forming a reaction zone (10A) containing said biomass feedstock; - propagating, under predetermined reaction conditions, an extraction fluid (1) in gas phase through said reaction zone (10A) containing said biomass feedstock, whereby target compounds (C1, C2) are separated from the essentially solid feedstock material; - collecting the thus separated target compounds (C1, C2) exiting said reaction area (10A); Including, by advancing through the biomass material along the length of the reaction zone, the extraction fluid carries the separated target compounds towards the end of the reaction zone, such that upon recovery the collected extract (2) is essentially liquid; The target compounds are extracted in fractions, such that the target compounds forming different fractions are eluted at different retention times. method.

2. 2. The method of claim 1, comprising heating and optionally pressurizing the extraction fluid in a first heat transfer unit (9) before directing the extraction fluid to the reaction zone, wherein the extraction fluid is vaporized to form a gas phase.

3. 3. The method of claim 1 or 2, wherein prior to the formation of the gas phase, the extraction fluid is an aqueous solution, optionally water.

4. 10. The method according to any one of the preceding claims, wherein the biomass feedstock is cellulose-containing biomass, in particular lignocellulosic biomass, and / or animal-derived biomass.

5. 10. The method according to any one of the preceding claims, wherein the extraction fluid is directed to the reaction zone (10A) continuously or in pulses.

6. 10. A process according to any one of the preceding claims, wherein the reaction conditions comprise adjusting the temperature in the reaction zone to a range of from 100 to 220°C, preferably from 150 to 210°C.

7. 10. The method of any one of the preceding claims, wherein the reaction conditions include adjusting the pressure in the reaction zone to a range of from about 0.3 MPa to about 3 MPa, preferably from about 1 MPa to about 2 MPa.

8. 10. The method according to any one of the preceding claims, wherein the flow of the extraction fluid through the reaction zone is adjusted so that the residence time spent by the separated target compounds in the reaction zone is in the range of from about 2 minutes to about 30 minutes, preferably in the range of from about 5 minutes to about 15 minutes.

9. 10. The method according to any one of the preceding claims, wherein recovering the target compounds leaving the reaction zone (10A) comprises cooling the extraction fluid carrying the target compounds (C1, C2) in a second heat transfer unit (11) arranged downstream of the reaction zone, thereby producing an essentially liquid extract (2) enriched in the target compounds.

10. 10. The method according to any one of the preceding claims, wherein the amount of extraction fluid for recovering the target compounds is about 0.1-10% by volume, preferably about 0.5-2% by volume, of the biomass feedstock fed into the reaction zone, the volume of extraction fluid being calculated according to its liquid state.

11. 10. The method according to any one of the preceding claims, wherein the dry matter content in the essentially liquid extract (2) collected upon harvesting and containing the target compounds is in the range of about 5% to about 30% by weight.

12. 10. The method of any one of the preceding claims, wherein prior to extraction with the extraction fluid, the biomass feedstock is pretreated with a pretreatment fluid to recover at least volatile compounds, the pretreatment being carried out at a temperature in the range of 70 to 120°C and a pressure in the range of about 0.05 mPa to about 0.5 MPa.

13. The method of claim 12 , wherein the pretreatment fluid is a gaseous substance such as a vapor or gas.

14. 10. The method according to any one of the preceding claims, wherein the reaction zone (10A) is formed in the device (10) for processing biomass configured as a batch reactor, a continuous flow reactor, or a combination thereof.

15. 10. The method of any one of the preceding claims, wherein the target compounds are selected from the group consisting of cellulose, hemicellulose, lignin, sugars, proteins, and low molecular weight extractable compounds such as terpenoids, phenolic compounds, fatty acids, resin acids, etc.

16. 10. The method of any one of the preceding claims, wherein the target compound is essentially intact long-chain hemicellulose.

17. A system (100) for separating and recovering compounds from biomass, said system comprising: - a device (10) for processing said biomass in a reaction chamber containing a biomass feedstock, whereby a reaction zone (10A) is formed; - means for directing an extraction fluid in gas phase into the reaction chamber, whereby said extraction fluid propagates through said reaction zone, separating target compounds (C1, C2) from said essentially solid feedstock material, and advances through said biomass material, said aqueous extraction fluid carrying the thus separated target compounds towards said end of said reaction zone; a first heat transfer unit (9) in which the extraction fluid is heated and optionally pressurized to form a gas phase before entering the reaction chamber; a second heat transfer unit (11) in which the extraction fluid leaving the reaction zone is condensed to produce an essentially liquid extract enriched in the target compound; - at least one control device for regulating reaction conditions in said reaction chamber; Equipped with The target compounds are extracted in fractions, so that the target compounds forming different fractions are eluted at different retention times. system.

18. 1. A method for separating and recovering essentially intact hemicellulose compounds from lignocellulosic biomass, comprising: - providing a lignocellulosic biomass feedstock to an apparatus for processing biomass, thereby forming a reaction zone containing said biomass feedstock; - propagating steam as an extraction fluid through the reaction zone containing the biomass feedstock at predetermined reaction conditions, thereby separating hemicellulose compounds from the essentially solid feedstock material; - recovering the thus separated intact hemicellulose compounds leaving the reaction zone; Including, by advancing through the biomass material along the length of the reaction zone, the aqueous extraction fluid carries the separated hemicellulose compounds toward the end of the reaction zone, such that the collected extract is essentially liquid upon recovery; the hemicellulose compounds are extracted in fractions, such that the intact hemicellulose compounds and the degradation products forming different fractions are eluted at different retention times; method.

19. 19. The method of claim 18, comprising adjusting the temperature in the reaction zone to a range of about 160 to 220°C and adjusting the pressure in the reaction zone to a range of about 0.6 to 2.5 MPa, thereby obtaining a fraction that accounts for 80 to 95% of the total amount of intact hemicellulose compounds.

Images