BR112019000295B1 - METHODS FOR REFINING A LIGNOCELLULOSIC HYDROLYZATE - Google Patents

Abstract

The present disclosure relates to processing and refining lignocellulosic biomass to produce chemocellulose and cellulose sugars. Methods and systems for refining a lignocellulosic hydrolyzate are provided herein.

Description

CROSS REFERENCE

[0001] This application claims the benefit of United States Provisional Application No. 62/359,145, filed on July 6, 2016, incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Lignocellulosic biomass materials are renewable sources for the production of amino acids for foods and food supplements, monomers and polymers for the plastics industry, and renewable sources for different types of fuels, polyol sugar substitutes (xylitol, sorbitol, mannitols, and the like), and numerous other chemicals that can be synthesized from C5 and C6 sugars. However, efficient and cost-effective processes to extract C5 and C6 sugars from biomass are still a challenge.

[0003] Classical corn milling sugar refining comprises a sequence of resin-based ion exchangers to remove cations, anions, non-ionic compounds, and colored bodies. This technology has been well developed for starch hydrolysates since the 1960s and 1970s, and is still the method of producing corn sugars and another facility for hydrolyzing feed stocks.

[0004] It is well known that methods applied to the production of 1st generation sugars, that is, from starch or sucrose feed stocks, are very costly when applied to the production of 2nd generation sugar, that is, from biomass. Biomass hydrolysis requires more severe conditions to effectively hydrolyze it as compared to starch. For example, stronger and/or more concentrated acids are used, and temperature and/or pressure of reactions are increased, all resulting in greater formation of degradation products that must be removed. Much of the increased cost is due, in part, to the impact of organic acids, which are an inherent component of biomass hydrolysates on WBA resin.

[0005] Biomass anions associated with organic acids can be adsorbed by WBA, their adsorption is accompanied by a marked shrinkage of the resin, ten times greater than the shrinkage caused by mineral acid. Inherently, the resin maintains a finite number of adsorption sites (e.g., the number of ammonia groups in a given volume of resin is finite), and, once exhausted, the resin is regenerated by: (i) washing the resin with water to recover sugar from the resin volume, producing a “sweet water” having 2-4% sugars; (ii) periodic regeneration with mineral acid to remove organic acid; (iii) regeneration with caustic soda or soda ash to prepare the resin for the next cycle; and (iv) a final wash to remove excess base. Consequently, when the base resin is regenerated, the resin retracts. In the adsorption cycle, the resin shrinks again. The result of these retraction and collision cycles mechanically crushes the resin into dust, leading to poor mass transfer in washing, production and regeneration functions and, eventually, frequent need to replace the resin at high cost. When applied to the refining of bagasse hemicellulose hydrolyzate, the shelf life of a WBA resin is about half that for the typical corn sugar refining operation. Other feedstocks release higher amounts of acetic acid on hydrolysis, such as eucalyptus, shortening resin life even further.

SUMMARY OF THE INVENTION

[0006] In view of the foregoing, there is a pressing need for efficient methods for refining and deacidifying lignocellulosic hydrolysates on industrial scales. The present disclosure addresses this need by providing new methods and systems for refining hydrolysates with a liquid anion exchange medium. For industrial purposes, the methods described here can be carried out using industrially available means and machines that can support high production rates at low costs, while maintaining high purification energy. It is the objective of the present disclosure to achieve such an increase in the process to a size that allows the production of at least 7,000 tons of purified xylose per year, or more.

[0007] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate, comprising (a) contacting at least 250 parts of the lignocellulosic hydrolyzate with 1 part of a liquid anion exchange medium (LAEM); and (b) recovering at least 225 parts of an aqueous stream, in which the aqueous stream comprises one or more sugars. In some examples, the at least 250 parts comprise at least 1000 parts, and the at least 225 parts comprise at least 900 parts. The at least 250 parts may comprise at least 10,000 parts, and the at least 225 parts may comprise at least 9,000 parts. In some examples, LAEM is recycled periodically. Contact can occur in a continuous process. The continuous process may comprise steps of washing, neutralizing, and refining the LAEM portion. In some examples, at any given time, a ratio of LAEM to lignocellulosic hydrolyzate is less than 5:1. In some examples, contact occurs in a liquid-liquid separation centrifuge.

[0008] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate, comprising (a) contacting the lignocellulosic hydrolyzate with a first portion of a liquid anion exchange medium (LAEM) in a liquid-separation centrifuge. liquid to form a mixture; (b) separating the mixture in the liquid-liquid separation centrifuge into an organic stream and an aqueous stream, in which the organic stream comprises the LAEM, an acid and an impurity, and in which the aqueous stream comprises one or more sugars; (c) contacting the organic stream with a base, thereby forming a neutralized mixture; and (d) recovering a second portion of a LAEM from the neutralized mixture; in which steps (a) to (b) are a continuous process. In some examples, steps (a) through (d) are an ongoing process. In some examples, steps (a) to (d) are completed within 90 min. In some examples, steps (a) and (b) are completed within 60 min. Optionally, steps (a) and (b) are completed within 30 min. Optionally, steps (a) and (b) are completed within 15 min. Optionally, steps (a) and (b) are completed within 5 min. In some examples, the method further comprises washing the organic stream with water to remove residual sugar from the organic stream, thereby forming a dilute solution of sugar and water, and a washed organic stream. In some examples, the diluted sugar and water solution is combined with the aqueous stream, in which the combined stream comprises at least 3.8% weight/weight sugars. In some examples, the base is added as an aqueous suspension or solution. The base can be lime. In some examples, the base is added as an aqueous solution. The base can be NaOH. In some examples, the pH of the neutralized mixture is between 6 and 7. In some examples, the method comprises washing the second portion of a LAEM with water, thereby forming a washed LAEM. A portion of the washed LAEM can be contacted with a second base. The portion of the washed LAEM may comprise less than 20% of the washed LAEM. Optionally, the pH of the base is at least 13.

[0009] In some examples, the method further comprises repetition of steps (a)-(d), in which the second portion of a LA-EM recovered in step (d) is reused in step (a) as the first portion of a LAEM when repeating steps (a)-(d). The volume of the second portion of a LAEM after repetition may be at least 80% of the volume of the first portion of a LAEM before repetition. The volume of the second portion of a LAEM after repetition may be at least 90% of the volume of the first portion of a LAEM before repetition. The volume of the second portion of a LAEM after repetition may be at least 95% of the volume of the first portion of a LAEM before repetition, such as at least 97.5% of the volume of the first portion of a LAEM before repetition. In some examples, the method is repeated at least 45 times in a day. In some examples, the ratio of the first portion of a LAEM to the lignocellulosic hydrolyzate is less than 5:1. In some examples, the LA-EM comprises an amine, wherein the amine comprises at least 20 carbon atoms. The amine may be a tertiary amine, such as tri-laurylamine. In some examples, the LAEM additionally comprises a diluent. The diluent may comprise a C6-16 alcohol or kerosene, such as hexanol or 2-ethylhexanol. The diluent may be 2-ethylhexanol. In some examples, the ratio of amine to diluent is between 1:7 and 7:1 weight/weight. In some examples, the lignocellulosic hydrolyzate comprises at least 0.1% weight/weight acid. The lignocellulosic hydrolyzate may comprise at least 0.5% weight/weight acid.

[0010] In some examples, the acid comprises an inorganic acid and an organic acid. In some examples, the aqueous stream comprises less than 200 ppm calcium. In some examples, the aqueous stream comprises arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars. In some examples, the aqueous stream comprises disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars. In some examples, the aqueous stream comprises ash in an amount of up to 0.25% weight/weight. In some examples, the aqueous stream comprises less than 1000 ppm acetic acid. In some examples, the aqueous stream comprises less than 1000 ppm of formic acid. In some examples, the aqueous stream comprises less than 1000 ppm sulfuric acid. In some examples, the aqueous stream comprises less than 1000 ppm hydrochloric acid. In some examples, the aqueous stream comprises less than 0.5% weight/weight acid, such as less than 0.1% weight/weight acid. In some examples, the aqueous stream comprises phenolic compounds in an amount of up to 500 ppm. In some examples, the aqueous stream comprises furfural in an amount of up to 500 ppm. In some examples, the aqueous stream comprises nitrogen in an amount of up to 1000 ppm.

[0011] In certain aspects, the present disclosure provides a system for refining a lignocellulosic hydrolyzate, comprising (a) a hydrolyzate refining unit comprising a first inlet for receiving a stream of lignocellulosic hydrolyzate, a second inlet for receiving a stream of recycled LAEM, a first flush to release an organic stream, and a second flush to release an aqueous stream; and (b) a neutralization unit in fluid communication with the hydrolyzate refining unit, wherein the neutralization unit comprises an inlet for receiving the organic stream, and a second inlet for receiving a base, in which the neutralization unit is configured to convert the organic stream to the recycled LAEM stream, and further in which the neutralization unit comprises a first discharge to release the recycled LAEM stream into fluid communication with the second inlet of the hydrolyzate refining unit. In some examples, the hydrolyzate refining unit comprises a mixer-settler device, a centrifuge, a stirred tank, a column, or a combination thereof. The hydrolyzate refining unit may comprise a centrifuge. The centrifuge may be a liquid-liquid separation centrifuge. The hydrolyzate refining unit may comprise at least two liquid-liquid separation centrifuges.

[0012] In some examples, the hydrolyzate refining unit is in fluid communication with a LAEM refining unit, in which the LAEM refining unit comprises an inlet for receiving the organic stream. The LAEM refining unit may comprise a discharge to release an entrained sugar stream and a loaded organic stream. The LAEM refining unit may comprise a centrifuge, or a static mixer, and a decanter centrifuge. In some examples, the neutralization unit comprises a liquid-liquid separation centrifuge. The neutralization unit may comprise a mixing tank configured to mix the organic stream and the base. The neutralization unit may be in fluid communication with a cleaning unit. In some examples, the cleaning unit comprises an inlet for receiving at least 5% of the recycled LAEM stream, and in which the cleaning unit is configured to contact the recycled LAEM stream with a base, thereby forming a mixture . The cleaning unit may comprise a flush to release the mixture into the neutralization unit.

[0013] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, in which only illustrative embodiments of the present disclosure are shown and described. As will be understood, the present revelation is capable of other and different embodiments, and its various details are capable of modifications in various respects, all without departing from the revelation. Accordingly, the drawings and description are to be construed as illustrative in nature, and not as restrictive.

INCORPORATION BY REFERENCE

[0014] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference. U.S. Order Nos. 62/359,145 and 61/680,183, and PCT Order Nos. PCT/US2013/039585, PCT/US2014/053956, and PCT/US2016/012384, are incorporated herein by reference in their entireties.

DESCRIPTION OF FIGURES

[0015] The new features of the invention are set out with particularity in the attached claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description setting forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings, of which:

[0016] Fig. 1 shows a schematic perspective of exemplary conversion processes for converting biomass to a refined hemicellulose sugar stream.

[0017] Fig. 2 illustrates a schematic diagram of exemplary sequential processes for washing biomass.

[0018] Fig. 3 illustrates a schematic diagram of exemplary sequential processes for washing and dehydrating lignocellulosic biomass after extraction of hemicellulose sugars.

[0019] Fig. 4 is a schematic representation of an exemplary method of hemicellulose sugar extraction and purification in accordance with some embodiments of the present disclosure. GAC stands for granulated activated carbon. MB means mixed bed (e.g. mixed bed cation/anion resin).

[0020] Fig. 5 shows a simplified flow diagram of methods for treating lignocellulose material according to some embodiments of the disclosure.

[0021] Fig. 6 represents chromatographic fractionation of a refined sugar mixture to obtain an enriched xylose fraction and a mixed sugar solution containing glucose, arabinose, and a variety of DP2+ components.

[0022] Fig. 7 represents a schematic of an industrial production facility for refining a lignocellulosic hydrolyzate in accordance with certain embodiments of the present disclosure.

[0023] Fig. 8 represents a schematic of an industrial production facility for refining a lignocellulosic hydrolyzate in accordance with certain embodiments of the present disclosure.

[0024] Fig. 9 represents a schematic of an industrial production facility for refining a lignocellulosic hydrolyzate in accordance with certain embodiments of the present disclosure.

[0025] Fig. 10 represents a comparison of the amount of residual organic acid in a refined hydrolyzate when the diluent is either hexanol or 2-ethyl-1-hexanol.

DETAILED DESCRIPTION OF THE INVENTION

[0026] While various embodiments of the invention(s) of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention(s). It should be understood that various alternatives to the embodiments of the invention(s) described herein may be employed in the practice of any of the invention(s) set forth herein.

[0027] The present disclosure relates to the processing and refining of lignocellulosic biomass to produce hemicellulose and cellulose sugars, and the conversion of these into high-value products. In particular, the present disclosure provides methods and systems for refining a lignocellulosic hydrolyzate. The methods and systems described here are particularly effective in removing acids and impurities from a lignocellulosic hydrolyzate on an industrial scale at high efficiency. Methods and systems for recycling various streams in the process are also described.

[0028] The terms “liquid anion exchange medium”, and “LAEM”, as used herein, generally refer to a weak base anion exchanger in liquid form. Typically, LAEM may have very low water solubility (e.g. 10g/100g water at 25°C). LAEM may comprise an amine that can extract non-toxic impurities. During extraction, the amine may have similar functional groups as a WBA resin. LAEM may additionally be dissolved in a solvent (e.g. diluent). Preferably, the diluent can (i) dissolve well both the free tertiary amine R3N and its bound form R3NH+A-; (ii) control viscosity to an industrially useful range, allowing the use of low-cost systems, such as mixer-settlers and/or liquid-liquid centrifuges; (iii) additionally contribute to the solvent's ability to extract non-ionic impurities; and/or (iv) allows regeneration of the charged phase by efficient contact with mineral bases, such as caustic or lime.

[0029] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate. In some examples, the method comprises (a) contacting at least 250 parts of the lignocellulosic hydrolyzate with 1 part of a liquid anion exchange medium (LAEM), and (b) recovering at least 225 parts from an aqueous stream, in which the aqueous stream comprises one or more sugars.

[0030] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate. In some examples, the method comprises (a) contacting the lignocellulosic hydrolyzate with a first portion of a liquid anion exchange medium (LAEM) in a liquid-liquid separation centrifuge to form a mixture, (b) separating the mixture in the liquid-liquid separation centrifuge into an organic stream and an aqueous stream, in which the organic stream comprises LAEM, an acid, and an impurity, and in which the aqueous stream comprises one or more sugars, (c) contacting the stream organic mixture with a base, thereby forming a neutralized mixture, and (d) recovering a second portion of a LA-EM from the neutralized mixture. Steps (a) and (b) can be continuous. Optionally, steps (a) to (d) are continuous. The aqueous stream is also referred to herein as a “refined hemicellulose sugar stream.”

[0031] The lignocellulosic hydrolyzate can result from the hydrolysis of a lignocellulosic biomass. A biomass embodied in an object method or system disclosed herein is typically high in xylan content. Biomass can be derived from wood, softwood, hardwood, such as alder, aspen, birch, beech, maple, poplar, eucalyptus, and willow, plants or plant constituents, grains, such as wheat, barley, rice, rye and oats, grain particulates such as straw, husks, fiber, husks, and stalks, corn cobs, corn stover, corn fiber, walnut shells, almond shells, coconut shells, bagasse, corn seed meal cotton, and cottonseed hulls. When wood is used as a starting material, it is advantageously used as shavings or sawdust. Preferably, the biomass is selected from hardwood, such as birch and eucalyptus, bagasse, and sugar cane leaves, or a combination thereof. Optionally, the biomass comprises one or more sugar cane bagasse and sugar cane leaves.

[0032] A lignocellulosic hydrolyzate can be produced from foods selected from new bagasse, accumulated bagasse (more than 4 years), and sugar cane leaves. Hemicellulose sugars can be extracted from sugarcane leaves and other grasses to produce the hydrolyzate. Optionally, biomass feed stocks are mixed before hydrolysis. For example, a mixture of sugar cane bagasse and sugar cane leaves can be hydrolyzed together. Optionally, different hydrolyzate streams are mixed. For example, a sugar cane bagasse hydrolyzate and a sugar cane leaf hydrolyzate can be mixed before refining (e.g. LAEM refining). Optionally, streams derived from different feed stocks are mixed after refining (e.g. LAEM refining). Two types of feed can be available for xylose production. A method described herein can use two feed streams that are combined together in the LAEM refining process. For example, bagasse, old or new, can withstand the ash removal, hemicellulose extraction, and LAEM refining sequence. In another example, the leaves can support the hemicellulose extraction sequence for LAEM refining.

[0033] Leaves can be collected and baled in the field, and brought into the facility. Leaves cannot contain high amounts of “physical” ash, for example, grains of sand, such as bagasse, in which case there may not be a need to remove ash. The advantages of using sheets are described in PCT/US2016/012384. Extraction conditions can be optimized separately for each feed. Conditions may be milder for the leaves. Both feeds can be combined together from the refining stage, despite the difference in sugar composition in their respective hydrolysates and the different levels of various contaminants. The process can maintain both types of hydrolysates at high xylose levels of at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, or at least about 75% weight/weight xylose/total monomers.

[0034] An exemplary conversion process scheme for converting biomass into a refined hemicellulose sugar stream is provided in Fig. 1. Optionally, lignocellulose-containing biomass is pretreated (170) prior to extraction of hemicellulose sugars. lose. In some examples, pretreatment of the biomass may not be required, that is, the lignocellulose-containing biomass may be used directly in the extraction of sugar from hemicellulose. A schematic diagram of exemplary countercurrent processes for washing biomass is provided in Fig. 2. Pretreatment may comprise a reduction in the size of the biomass (e.g., mechanical breaking, milling, or grinding). Optionally, the lignocellulose-containing biomass is crushed such that the average size of the resulting biomass particles is between about 100 to 1,000 microns, such as about 400-5,000 microns, about 100-400 microns, about 400- 1,000 microns, about 1,000-3,000 microns, about 3,0005,000 microns, or about 5,000-10,000 microns. The average size of crushed biomass particles can be smaller than 10,000 microns, smaller than 9,000 microns, smaller than 8,000 microns, smaller than 7,000 microns, smaller than 6,000 microns, smaller than 5,000 microns, smaller than 4,000 microns, less than 3,000 microns, less than 2,000 microns, less than 1,000 microns, or less than 500 microns.

[0035] Pretreatment of biomass containing lignocellulose may comprise reducing the ash and soil content of the biomass prior to extracting hemicellulose sugars from the biomass. In some examples, lignocellulose-containing biomass comprising greater than about 4% weight/weight, greater than about 5% weight/weight, greater than about 6% weight/weight, greater than about 7% % weight/weight, or greater than about 8% weight/weight of apparent ash, such as 4% to 8% weight/weight of apparent ash (as measured by incineration of a dry sample of the biomass in accordance with NREL/ TP-510-42622) is devoid of soil and devoid of ash. Ash values greater than about 4% may be indicative of physical incorporation of soil particles into biomass during the growing season, in which soil particles contact and are enclosed by biomass as they grow. The reduction of ash and soil content of the biomass may comprise one or more stages of pulping, washing, and dehydration of the biomass. A method for reducing ash and soil content may comprise at least one and up to n stages of re-pulping and grinding (e.g., shredding) the biomass, and at least one and up to m stages of washing and dehydrating the biomass, where n is 2, 3, 4, 5, 6, 7, 8, 9, or 10, and m is 2, 3, 4, 5, 6, 7, 8, 9, or 10. Optionally, n is equal to m. In some examples, m is greater than n, or n is greater than m. Two or more such cycles of shear treatment and high pressure washing may be necessary to reduce the ash content of the biomass to less than 6%, less than 5%, less than 4%, or less than 3% weight/weight of ash, such as 3%-6% weight/weight of ash.

[0036] Hemicellulose sugars can be extracted from lignocellulosic biomass by any suitable method (100, Fig. 1), for example, using an aqueous acid solution. The aqueous acid solution may comprise any acid, such as an inorganic acid or an organic acid. Preferably, the solution may comprise an inorganic acid, such as H2SO4, H2SO3 (which may be introduced as dissolved acid or as SO2 gas), or HCl. In some examples, the aqueous acid solution may comprise an inorganic acid and/or an organic acid, including, for example, H2SO4, H2SO3, HCl, or acetic acid, or combinations thereof. In some examples, the aqueous acid solution does not comprise HCl. The acidic aqueous solution may contain an acid in an amount of about 0 to 2% acid or more, such as about 0-1.0%, about 0-1.5%, about 0.51.5 %, about 0.5-2.0%, about 1.0-2.0%, about 1.5-2.0%, about 0.2-1.0%, about 0, 2-0.7%, about 0-0.2%, about 0.2-0.4%, about 0.4-0.6%, about 0.6-0.8%, about from 0.8-1.0%, about 1.0-1.2%, about 1.2-1.4%, about 1.4-1.6%, about 1.6-1 .8%, or about 1.8-2.0% weight/weight. Optionally, the aqueous solution for extraction includes 0.2 - 0.7% H2SO4 and 0 - 3,000 ppm SO2. The pH of the acidic aqueous solution can be in the range of about pH 1 to pH 5, such as about pH 1 to pH 3.5.

[0037] High temperature or pressure can be used to extract hemicellulose sugars from biomass. In some examples, a temperature in the range of about 100 - 200°C may be used. A temperature of more than 50°C, more than 60°C, more than 70°C, more than 80°C, more than 90°C, more than 100°C, more than 110°C , more than 120°C, more than 130°C, more than 140°C, more than 150°C, more than 160°C, more than 170°C, more than 180°C, more than 190°C, or more than 200°C, such as 60°C to 190°C, can be used in extraction. Preferably, the temperature is in the range of 90-170°C, such as 100-165°C, 110-160°C, 120-150°C, 130-155°C or 140-150°C. The pressure may be in the range of about 0.4 - 10 mPa, such as 0.4 - 5 mPa. Optionally, the pressure is less than 20 mPa, such as less than 10 mPa, less than 9 mPa, less than 8 mPa, less than 7 mPa, less than 6 mPa, or less than 5 mPa. mPa. In some examples, the extraction mixture may be heated for 0.1 - 5 hours, preferably 0.1 - 3 hours, 0.1 - 1 hour, 0.5 - 1.5 hours, 0.5 - 2 hours, 1-2 hours, or 2-3 hours. The extraction process may have a cooling period of less than one hour. Optionally, hemicellulose sugars are extracted from the biomass by contacting the biomass with an aqueous acid solution, and heating the resulting mixture to a temperature of more than 50 ° C at a pressure of less than 10 mPa.

[0038] Hemicellulose sugar extraction can produce, in a single extraction process, a hemicellulose sugar stream (100-A) containing at least 75% monomeric sugars, such as more than 80%, more than 85%, more than 90%, more than 91%, more than 92%, more than 93%, more than 94%, more than 95%, more than 96%, more than 97%, more than 98%, or more than 99% monomeric sugars. The hemicellulose sugar stream may contain 80-99% monomeric sugars. In some examples, at least about 70%, at least 75%, at least 80%, at least 85%, at least 90%, or even at least 95% or more of the hemicellulose sugars, such as 70% to 95%. % of the hemicellulose sugars present in the biomass can be extracted using a development method. Sugar extraction from hemicellulose can produce minute amounts of lignocellulose degradation products, such as furfural, hydroxymethyl furfural, levulinic acid, and formic acid. A xylose yield of greater than 70%, optionally greater than 80%, of theoretical value can be achieved.

[0039] Extraction of hemicellulose sugars from biomass can result in a remaining stream of lignocellulose (100-P1) comprising lignin and cellulose. A schematic diagram of exemplary sequential processes for washing and dehydrating a remaining lignocellulose stream after extraction of hemicellulose sugars is provided in Fig. 3. Alternatively, the remaining lignocellulose stream can be separated from the hemicellulose sugar stream by means of of a vacuum belt filter and/or a filter press system. Vacuum belt filter systems are commercially available from several suppliers, including, for example, Pannevis, BHS-Sonthofen Inc. and FLSmidth. In some examples, slurry extraction may be continuously fed onto a moving belt. As the belt moves, vacuum can be applied to remove liquids and create a filter cake that settles on the moving belt. Optionally, the chorea may pass through a washing zone. Optionally, the belt can pass through a drying zone. A wash zone may comprise nozzles that spray a wash fluid onto the filter cake (i.e., the remaining lignocellulose stream) to rinse residual hemicellulose sugars from the remaining lignocellulose stream, thereby increasing the recovery of hemicellulose sugars. hemicellulose.

[0040] In some examples, the extraction of hemicellulose sugars may not remove a substantial amount of the cellulosic sugars. For example, extraction of hemicellulose sugars may not remove more than 1%, more than 2%, more than 5%, more than 10%, more than 15%, more than 20%, more than than 30%, more than 40%, more than 50%, or more than 60% weight/weight of cellulose, such as 2%-40% weight/weight of cellulose. In some examples, the remaining lignocellulose stream comprises less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20 %, less than 15%, less than 10%, less than 5%, less than 2%, or less than 1% weight/weight of hemicellulose, such as 2% to 45% weight/weight of hemicellulose . The remaining lignocellulose stream may comprise less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4% , less than 3%, less than 2%, or less than 1% weight/weight of ash, such as 2% to 9% weight/weight of ash. In some examples, the remaining lignocellulose stream comprises 0.001-5% wt/wt of ash, such as 0.01-4%, 0.1-3%, 0.12%, or 0.1-1% wt/wt. ash weight. In some examples, the remaining lignocellulose stream comprises lignin, cellulose, hemicellulose in an amount of less than 5% weight/weight, and ash in an amount of less than 4% weight/weight. In some examples, less than 10%, less than 5%, less than 4%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, or less than 1% of the lignocellulose solids, such as 1% to 5% of the lignocellulose solids remain in the hemicellulose sugar stream. Optionally, the remaining lignocellulose stream comprises less than 75%, less than 65%, less than 55%, less than 45%, less than 35%, less than 25%, less than 15%, or less than 10% weight/weight water, such as 15% to 65% weight/weight water. The remaining lignocellulose stream may comprise more than 20%, more than 30%, more than 40%, more than 50%, more than 60%, more than 70%, or more than 80% by weight. /weight solids, such as 30% to 70% weight/weight solids. The remaining lignocellulose stream may comprise less than 10%, less than 7.5%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1% , or less than 0.5% weight/weight of residual soluble carbohydrates. In some examples, the remaining lignocellulose stream comprises about 0.01-5% weight/weight soluble carbohydrates, such as 0.15%, 0.5-5%, 0.5-2.5%, or 0. .1-2.5% w/w soluble carbohydrates. The remaining lignocellulose stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0, 2%, or less than 0.1% weight/weight sulfate. In some examples, the remaining lignocellulose stream comprises 0.001-3% wt/wt sulfate, such as 0.01-3%, 0.01-2%, 0.01-1%, or 0.001-1% wt/wt. sulfate weight. The remaining lignocellulose stream may comprise soluble carbohydrates in an amount relative to total solids of less than 5%, ash in an amount relative to total solids of less than 4%, and sulfate in an amount relative to total solids of less than than 3%.

[0041] Impurities such as ash, water-soluble lignin, furfural, fatty acids, organic acids, such as acetic acid and formic acid, proteins and/or amino acids, glycerol, sterols, rosin acid or waxy materials, or combinations thereof , can be extracted together with the hemicellulose sugars under the same conditions in the hemicellulose sugar stream. At least some of these impurities can be separated from the hemicellulose sugar stream by solvent extraction (e.g., using a LAEM).

[0042] The hemicellulose sugar stream can be refined and, optionally, fractionated according to the processes disclosed in PCT/US2013/039585, incorporated herein by reference. The hemicellulose sugar stream may optionally be filtered, centrifuged, or concentrated by evaporation. Optionally, the hemicellulose sugar stream is contacted with a strong acid cation exchanger (e.g., in the form of H+) to convert salts to respective acids. In some examples, the hemicellulose sugar stream may first be contacted with a strong cation exchange resin, and then contacted with a LAEM.

[0043] Prior to purification of hemicellulose sugar 110, the acidic hemicellulose sugar stream 100-A from the extraction of hemicellulose sugar 100 may optionally be filtered, centrifuged, or concentrated by evaporation. For example, the hemicellulose sugar stream can be contacted with a strong acid cation exchanger (e.g., in the form of H+) to convert all salts to their respective acids.

[0044] The purification of hemicellulose sugar 400 is illustrated in greater detail according to an exemplary embodiment of the present disclosure as shown in Fig. 4. As illustrated in Fig. 4, the acidic hemicellulose sugar stream 400-A is first subjected to a strong cation exchange resin and then LAEM 431 extraction, during which acids and impurities are extracted from the hemicellulose sugar stream in the LAEM. The acid-depleted hemicellulose sugar stream 431-B is then purified by ion exchange 432, including a strong acid cation exchanger (SAC) 433 and optionally followed by a weak base anion exchanger (WBA) 434 The de-amined and neutralized hemicellulose sugar stream 432-A is optionally evaporated 435 to form a hemicellulose sugar mixture 436. Optionally, the de-amined and neutralized hemicellulose sugar stream 432-A may also be refined by contact with granulated activated carbon before evaporation 435.

[0045] The hemicellulose sugar mixture 436 can be refined by contact with granulated activated carbon 439 and refined with mixed bed 440 before evaporation at higher concentration (process 1838 in Fig. 4) to produce a hemicellulose sugar mixture. lose 444. The hemicellulose sugar mixture 436 can be optionally fractionated (process 437 in Fig. 4) to obtain high purity C5 sugars, such as xylose. Fractionation can be carried out by any means, preferably using a simulated moving bed (SMB), or simulated sequential moving bed (SSMB). Fractionation can produce a sugar mixture of xylose-removed hemicellulose (120-P3 and 437-B). Examples of simulated moving bed processes are disclosed, for example, in U.S. Pat. No. 6,379,554, U.S. Pat. No. 5,102,553, U.S. Pat. No. 6,093,326, and U.S. Pat. No. 6,187,204, examples of sequential simulated moving bed processes can be found in GB 2,240,053 and U.S. Pat. No. 4,332,623, as well as U.S. Pat. Us. 4,379,751 and 4,970,002, each of the entire contents of which is incorporated herein by this reference. In an exemplary SMB or SSMB installation, the resin bed is divided into a series of discrete vessels, each of which is sequenced through a series of 4 zones (feed, separation, feed/separation/raffinate, and safety), and connected by a closed recirculation circuit. A collector system can connect the vessels, and can direct, in appropriate sequence to (or from) each vessel, each of the four media accommodated by the process. These media can be generally referred to as food, eluent, extract and raffinate. For example, a feed may be hemicellulose 436 sugar mixture, the eluent may be water, the extract is an enriched xylose solution, and the rafinate is an aqueous solution containing high molecular weight sugars, and other monomeric sugars, that is, arabinose, galactose, and glucose. Optionally, the eluent may be an aqueous solution comprising a low concentration of hydroxide ion to maintain the resin in the hydroxyl form, or the eluent may be an aqueous solution comprising a low concentration of acid to maintain the resin in a protonated form. For example, a feed comprising a 30% sugar mixture where xylose is about 65-70% of the mixture can be fractionated using an SSMB to obtain an extract comprising about 16-20% sugars where xylose is about 82%. % or more, and a rafinate comprising 5-7% sugar mixture with only 15-18% xylose. Fig. 6 represents a chromatographic fractionation of a refined sugar mixture to obtain an enriched xylose fraction and a mixed sugar solution containing glucose, arabinose, and a variety of DP2+ components.

[0046] When an SSMB process is used for fractionation, xylose can exit from the extract stream and higher sugars, as well as glucose, galactose, and arabinose, can exit the rafinate stream. The xylose stream (120-P3 and 437-A) can optionally be refined by contact with granulated activated carbon, and refined with a mixed bed before evaporation to the highest concentration (process 438 in Fig. 4). The refined xylose stream 437-A is then optionally evaporated again and crystallized (see, for example, processes denoted in Fig. 4 by the number 441). The products may be a xylose crystal 442 and xylose-removed hemicellulose sugar mixture 443.

[0047] As shown in Fig. 5, at least a portion of the hemicellulose and impurities are extracted in hemicellulose sugar extraction 501 by liquid extraction (e.g., using an acidic aqueous solution). Extraction of hemicellulose sugar 501 can produce an acidic hemicellulose sugar stream and a lignocellulosic remainder stream. Sugar extraction from hemicellulose 501 may employ pressure cooking. The acidic hemicellulose sugar stream can be subjected to LAEM 502 extraction using a LAEM containing an amine having at least 20 carbon atoms, resulting in an aqueous stream and an organic stream. Optionally, the LAEM stream is subjected to a water wash followed by a bottom extraction 503 with a base. At least a portion of the LAEM stream may be subjected to purification and filtration 504 before it is recycled for reuse in LAEM extraction 502. The other portion of the stream may be returned directly for reuse in LAEM extraction 502. The aqueous stream resulting from Bottom extraction 503 may be subjected to cation exchange 505 and then distillation 506. Distillation 506 may be conducted to recover acids. Cation exchange 505 and distillation 506 may be optional.

[0048] A sugar stream can be contacted with a LAEM comprising an amine and a diluent, to remove at least one mineral acid, at least one organic acid, furfurals, and water-soluble lignins. Optionally, the extraction is a liquid-liquid extraction, and is carried out in a device suitable for liquid-liquid extraction, such as a liquid-liquid separation centrifuge. Optionally, the sugar stream is a lignocellulosic hydrolyzate, a hemicellulose sugar stream, or a hemicellulose sugar stream (400-A, see Fig. 4). Optionally, the hydrolyzate does not comprise hydrochloric acid.

[0049] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate. In some examples, the method comprises (a) contacting at least 250 parts of the lignocellulosic hydrolyzate with 1 part of a liquid anion exchange medium (LAEM), and (b) recovering at least 225 parts from an aqueous stream, in which the aqueous stream comprises one or more sugars. Because LAEM is recycled, the proportions above refer to the total volume of lignocellulosic hydrolyzate and LAEM present through all process cycles.

[0050] The at least 250 parts may comprise at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1000, at least about 1500, at least about 2000, at least about 5000, at least about 10,000, or at least about 20,000 parts, such as 500 to 10,000 parts. Preferably, a high percentage of the refined aqueous stream is recovered, such as at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99%. , such as 50% to 95%. Additionally, recovery of the at least 225 parts of the aqueous stream may comprise at least about 450, at least about 540, at least about 630, at least about 720, at least about 810, at least about 900, at least about 1350, at least about 1800, at least about 4500, at least about 9,000, or at least about 18,000 parts, such as 540 to 9,000 parts.

[0051] Contact and recovery can occur in a continuous process. Preferably, LAEM is recycled periodically. For example, new lignocellulosic hydrolyzate can be added to the 1 part of the LAEM, in which the 1 part of the LAEM is continuously recycled. The same portion of LAEM can be used to refine the lignocellulosic hydrolyzate over many cycles of a continuous process. Since the process cycle can be repeated at least 5, at least 10, at least 25, at least 50, at least 100, at least 150, at least 200, at least 250, at least 500, at least 750, at least 1000, at least 1500, at least 2000, at least 3000, at least 4000, at least 5000, at least 6000, at least 7000, at least 8000, at least 9000, or at least 10000 times, such as 10 to 9000 times using the same portion of LAEM, in which the LAEM is neutralized and/or refined after each cycle. In some examples, new LAEM is added to the method to produce the lost LAEM. Optionally, the continuous process comprises the steps of washing, neutralizing, and refining the LAEM. In a process cycle, a ratio of LAEM to lignocellulosic hydrolyzate is less than 7:1, less than 6:1, less than 5:1, less than 4:1, less than 3:1, less than 2:1, less than 1:1, or less than 1:2. At any given time, the ratio of LAEM to lignocellulosic hydrolyzate is less than 5:1. Contact may occur in a liquid-liquid separation centrifuge.

[0052] In certain aspects, the present disclosure provides a method for refining a lignocellulosic hydrolyzate. In some examples, the method comprises (a) contacting the lignocellulosic hydrolyzate with a first portion of a liquid anion exchange medium (LAEM) in a liquid-liquid separation centrifuge to form a mixture, and (b) separating the mixing in the liquid-liquid separation centrifuge into an organic stream and an aqueous stream, in which the organic stream comprises LAEM, an acid and an impurity, and in which the aqueous stream comprises one or more sugars. Optionally, the method further comprises (c) contacting the organic stream with a base, thereby forming a neutralized mixture, and (d) recovering a second portion of a LAEM from the neutralized mixture. In some examples, the lignocellulosic hydrolyzate is produced by the hydrolysis of a lignocellulosic biomass, such as sugar cane bagasse, or sugar cane leaves.

[0053] Preferably, steps (a) and (b) are continuous. For example, steps (a) and (b) may be occurring concurrently, in which the LAEM and lignocellulosic hydrolyzate are continuously introduced to the liquid-liquid separation centrifuge at the same time as the organic streams and aqueous streams are separated from the mixture. . Optionally, steps (a) to (d) are continuous. During repetition of steps (a)-(d), the second portion of a LAEM recovered in step (d) may be reused in step (a) as the first portion of a LAEM when repeating steps (a) -(d). In some examples, LAEM may be recycled in a closed continuous refining loop, while new lignocellulosic hydrolyzate is added, and the aqueous stream (e.g., a refined hemicellulose sugar stream) is removed. Steps (a) to (d) can be completed within 120 min, within 105 min, within 90 min, within 75 min, within 60 min, within 45 min, within 30 min, or within 15 min. Steps (a) and (b) can be completed within 120 min, within 105 min, within 90 min, within 75 min, within 60 min, within 45 min, within 30 min, within 15 min, or within 5 min, such as 15 min to 90 min.

[0054] LAEM may refer to a weak base anion exchanger in liquid form. Typically, LAEM may have very low water solubility (e.g. 10g/100g water at 25°C). LAEM may comprise an amine that can extract non-ionic impurities. During extraction, the amine may have similar functional groups as a WBA resin. LAEM may additionally be dissolved in a solvent (e.g. diluent). Preferably, the diluent can (i) dissolve well both the free tertiary amine R3N and its bonded form R3NH+A-; (ii) control viscosity to an industrially useful range, allowing the use of low-cost systems, such as mixer-settlers, and/or liquid-liquid centrifuges; (iii) additionally contribute to the solvent's ability to extract non-ionic impurities; and/or (iv) allow regeneration of the charged phase by efficient contact with mineral bases, such as caustic or lime.

[0055] LAEM may comprise 10-90% weight/weight, such as 20-60% weight/weight, of one or more amines having at least 20 carbon atoms. LAEM may comprise 10-90%, such as 1080%, 10-70%, 10-60%, 10-50%, 10-40%, 20-80%, 20-70%, 20-60%, 20 -50%, 20-40%, 15-80%, 15-70%, 15-60%, 15-50%, 15-40%, 1535%, 25-80%, 25-70%, 25-60 %, 25-50%, 25-40%, or 25-35% weight/weight of one or more amines having at least 20 carbon atoms. Such amine(s) may be primary, secondary, or tertiary amines. Tertiary amines may include, for example, tri-laurylamine (TLA; e.g., COGNIS ALAMINE 304 from Cognis Corporation; Tucson AZ; USA), tri-octylamine, tri-isooctylamine, tri-caprylylamine and tri-decylamine. Optionally, the LAEM comprises trilaurylamine. Preferably, the LAEM comprises a tertiary amine.

[0056] The LAEM may additionally comprise a diluent. In some examples, the LAEM may comprise at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least less than 90% weight/weight, such as 55-85% weight/weight, of a diluent. Suitable diluents for use in LAEM extraction may include an alcohol, such as butanol, isobutanol, hexanol, octanol, decanol, dodecanol, tetradecanol, pentadecanol, hexadecanol, octadecanol, eicosanol, docosanol, tetracosanol, and triacontanol. Preferably, the diluent may be a long-chain alcohol (e.g., C6, C8, C10, C12, C14, C16 alcohol), or kerosene. Optionally, the diluent is n-hexanol or 2-ethyl-1-hexanol (2E1H). Optionally, the diluent is 2-ethyl-1-hexanol. The diluent may consist essentially of, or consists of, 2-ethyl-1-hexanol. Optionally, the diluent comprises one or more additional components, such as a ketone, an aldehyde having at least 5 carbon atoms, or another alcohol.

[0057] Optionally, the LAEM comprises an amine having at least 20 carbon atoms and a diluent (e.g., an alcohol), such as a tertiary amine having at least 20 carbon atoms and an alcohol. In some examples, the LAEM may comprise a tertiary amine having from 20 to 50 carbon atoms and a diluent, in which the diluent is a C6-12 monoalcohol. In some examples, the LAEM may comprise an amine having 24-40 carbon atoms (e.g., trilaurylamine, trioctylamine, tricaprylylamine, or tridecylamine) and a diluent, in which the diluent may be a C6-12 monoalcohol (e.g. example, hexanol, octanol, or 2-ethylhexanol). In some examples, the amine may be trilaurylamine, and the diluent may be hexanol or 2-ethylhexanol. Optionally, the LAEM does not comprise an exogenous acid. Acid extracted from a lignocellulosic hydrolyzate may be present in recycled LAEM, although typically no exogenous acid is added to LAEM by other means.

[0058] In some examples, the amine may be trilaurylamine and the diluent may be C6-12 monoalcohol, such as 2-ethyl-1-hexanol. LA-EM may comprise an amine and a diluent in a ratio between 1:10 and 10:1 weight/weight, such as 1:7, 2:7, 3:7, 6:4, 5.5:4.55, 4: 7, 5:7, 6:7, 7:7, 5:4, 3:4, 2:4, or 1:4 weight/weight. The ratio of amine and diluent can be any ratio, for example, between 3:7 and 6:4 weight/weight. In some examples, the LAEM may comprise trilaurylamine and a C6-12 monoalcohol in a ratio of 1:7, 2:7, 3:7, 6:4, 5.5:4.55, 4:7, 5:7, 6 :7, 7:7, 5:4, 3:4, 2:4, or 1:4 weight/weight. Preferably, the LAEM may comprise trilaurylamine and a C6-12 monoalcohol in a ratio of about 3:7 weight/weight, such as a 3:7 weight/weight ratio of trilaurylamine and 2-ethyl-1. -hexanol.

[0059] Exemplary conversion processes for the purification of the hemicellulose sugar stream (100-A and 400-A) are depicted in Fig. 1 and Fig. 4, including LAEM extraction. In some examples, organic stream 431-A may comprise LAEM and at least one impurity. Optionally, at least one impurity may be selected from a mineral acid (e.g., H2SO4, H2SO3, and HCl), an organic acid (e.g., acetic acid and formic acid), furfural, hydroxymethylfurfural, and water-soluble lignin. . The aqueous stream may comprise hemicellulose sugars. After separation from the organic stream, the aqueous stream is referred to herein as a refined hemicellulose sugar stream (110-P1 and 431-B).

[0060] The ratio of the first portion of a LAEM to the lignocellulosic hydrolyzate may be less than 10:1, less than 9:1, less than 8:1, less than 7:1, less than 6:1, less than 5:1, less than 4:1, less than 3:1, less than 2:1, or less than 1:1, such as less than 5:1. The lignocellulosic hydrolyzate may comprise at least 0.05%, at least 0.1%, at least 0.2%, at least 0.3%, at least 0.4%, at least 0.5%, at least 0 6%, at least 0.7%, at least 0.8%, at least 0.9%, at least 1%, or at least 5% weight/weight of acid, such as at least 0.1% to 5% weight/weight acid. The acid may comprise an inorganic acid and an organic acid.

[0061] The organic stream can be washed with water to remove residual sugar from the organic stream, thereby forming a dilute solution of sugar and water and a washed organic stream. The diluted sugar and water solution can be combined with the aqueous stream. The combined stream may comprise at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about of 7%, at least about 8%, at least about 9%, at least about 10%, at least about 15%, or at least about 20% weight/weight of sugars, such as 2% to 10% weight/weight of sugars.

[0062] Typically, a vast majority of sugars may remain in the depleted aqueous stream of acid 431-B, whereby much of the organic acids and/or inorganic acids (e.g., the acids used in extracting sugar from hemicellulose) and impurities may be extracted in organic stream 431-A. The organic stream 431-A can be contacted with water in a countercurrent mode to recover any residual sugars absorbed into the organic stream. Organic stream 431-A may contain less than about 5%, about 4%, about 3%, about 2%, about 1%, about 0.8%, about 0.6%, about 0.5%, about 0.4%, about 0.3%, about 0.2%, or less than about 0.1% weight/weight of hemicellulose sugars, such as 0. 1% to 4% weight/weight of hemicellulose sugars. The exhausted aqueous stream of acid 431-B may contain less than about 5%, about 4%, about 3%, about 2%, about 1%, about 0.8%, about 0. 6%, about 0.5%, about 0.4%, about 0.3%, about 0.2%, or less than about 0.1% weight/weight of acid, such as 0.2% to 5% weight/weight acid. The exhausted aqueous stream of acid 431-B may contain less than about 5%, about 4%, about 3%, about 2%, about 1%, about 0.8%, about 0. 6%, about 0.5%, about 0.4%, about 0.3%, about 0.2%, or less than about 0.1% weight/weight amine, such as 0 .2% to 4% w/w amine. The exhausted aqueous stream of acid 431-B may contain less than about 5%, about 4%, about 3%, about 2%, about 1%, about 0.8%, about 0. 6%, about 0.5%, about 0.4%, about 0.3%, about 0.2%, or less than about 0.1% weight/weight impurities, such as 0 .2% to 4% weight/weight impurities.

[0063] LAEM may comprise 10-90% weight/weight, such as 20-60% weight/weight, of one or more amines having at least 20 carbon atoms. LAEM may comprise 10-90%, such as 1080%, 10-70%, 10-60%, 10-50%, 10-40%, 20-80%, 20-70%, 20-60%, 20 -50%, 20-40%, 15-80%, 15-70%, 15-60%, 15-50%, 15-40%, 1535%, 25-80%, 25-70%, 25-60 %, 25-50%, 25-40%, or 25-35% weight/weight of one or more amines having at least 20 carbon atoms. Such amine(s) may be primary, secondary, or tertiary amines. Tertiary amines may include, for example, tri-laurylamine (TLA; e.g., COGNIS ALAMINE 304 from Cognis Corporation; Tucson AZ; USA), tri-octylamine, tri-isooctylamine, tri-caprylylamine and tridecylamine. Optionally, the LAEM comprises trilaurylamine.

[0064] The LAEM may additionally comprise a diluent. In some examples, the LAEM may comprise at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least less than 90% weight/weight, such as 55-85% weight/weight, of a diluent. Suitable diluents for use in LAEM extraction may include an alcohol, such as butanol, isobutanol, hexanol, octanol, decanol, dodecanol, tetradecanol, pentadecanol, hexadecanol, octadecanol, eicosanol, docosanol, tetracosanol, and triacontanol. Preferably, the diluent may be a long chain alcohol (e.g., C6, C8, C10, C12, C14, C16 alcohol), or kerosene. Optionally, the diluent is n-hexanol or 2-ethyl-1-hexanol (2E1H). Optionally, the diluent is 2-ethyl-1-hexanol. The diluent may consist essentially of, or consists of, 2-ethyl-1-hexanol. Optionally, the diluent comprises one or more additional components, such as a ketone, an aldehyde having at least 5 carbon atoms, or another alcohol.

[0065] Optionally, the LAEM comprises an amine having at least 20 carbon atoms, and a diluent (e.g., an alcohol), such as a tertiary amine having at least 20 carbon atoms, and an alcohol. In some examples, the LAEM comprises a tertiary amine having from 20 to 50 carbon atoms and a diluent, in which the diluent is a C6-12 monoalcohol. In some examples, the LAEM may comprise an amine having 24-40 carbon atoms (e.g., trilaurylamine, trioctylamine, tricaprylylamine, or tridecylamine) and a diluent, in which the diluent is a C6-12 monoalcohol (e.g., hexanol , octanol, or 2-ethylhexanol). In some examples, the amine may be trilaurylamine, and the diluent may be hexanol or 2-ethyl-1-hexanol.

[0066] In some examples, the amine may be trilaurylamine and the diluent may be a C6-12 mono-alcohol, such as 2-ethyl-1-hexanol. LAEM may comprise an amine and a diluent in a ratio between 1:10 and 10:1 weight/weight, such as 1:7, 2:7, 3:7, 6:4, 5.5:4.55, 4:7, 5:7, 6:7, 7:7, 5:4, 3:4, 2:4, or 1:4 weight/weight. The ratio of amine and diluent can be any ratio, for example, between 3:7 and 6:4 weight/weight. In some examples, the LAEM may comprise trilaurylamine and the C6-12 monoalcohol in a ratio of 1:7, 2:7, 3:7, 6:4, 5.5:4.55, 4:7, 5 :7, 6:7, 7:7, 5:4, 3:4, 2:4, or 1:4 weight/weight. Preferably, the LAEM may comprise trilaurylamine and the C6-12 monoalcohol in a ratio of about 3:7 weight/weight, such as a 3:7 weight/weight ratio of trilaurylamine and 2-ethyl-1-hexanol. .

[0067] Optionally, the 400-A sugar stream is drawn with the LAEM against the current, for example, the 400-A sugar stream flows in a direction opposite to the flow of the LAEM. Countercurrent extraction can be carried out using any suitable device. The suitable device may be selected from the group consisting of a centrifuge, a mixer-settler device, a stirred tank, and a column, or any combination thereof. The centrifuge may be a liquid-liquid separation centrifuge.

[0068] The liquid-liquid centrifuge may be a Rousselet Robatel BXP 190 model, with a nominal capacity of 150 gpm. The lignocellulosic hydrolyzate and LAEM, having a different density than that of the lignocellulosic hydrolyzate, can be fed into a mixing chamber. The mixing chamber may be located at the bottom of the centrifuge. The two liquids can typically be mixed by a rotating agitator disk. Efficient mixing can result in a large interfacial area between the two liquids to generate maximum mass transfer of the solutes.

[0069] A turbine can typically be located at the bottom of the rotating bowl. The turbine can aspirate the lignocellulosic hydrolyzate and disperse LAEM into the centrifugal bowl. The rotating bowl may be capable of generating a centrifugal force that separates the liquids. The heavier liquid can migrate to the outer portion of the vat, while the lighter liquid can migrate to the inner portion of the vat. A heavy phase dam can regulate the position of the liquid/liquid interphase. A selection of interchangeable heavy phase weirs with different diameters may be available to accommodate a wide range of density ratios. The heavy phase can flow into a static receiving chamber, and the light phase can overflow into a separate static receiving chamber.

[0070] Gravity can discharge the liquids to the next BXP centrifugal extractor, or to downstream equipment. During multi-stage extraction processes, liquid-liquid centrifuges can be installed in series to provide the required number of stages. Interstage pumps may not be required between extractors. External inter-stage piping can allow food to enter or exit the extraction process, e.g., main extraction, scrubbing, bottom extraction, as required for optimal flexibility.

[0071] The refining method can be conducted at any temperature at which the amine is soluble, preferably at 50-70°C. In some methods, the temperature may be at least about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C. C, about 75°C, or at least about 80°C. Optionally, the refining method comprises more than one extraction step (e.g., 2, 3, or 4 steps). The ratio of the first portion of the LAEM stream (organic stream) to the hemicellulose sugar stream (aqueous stream) can range from about 0.5:1 to about 5:1 weight/weight, such as about 0. 5:1, about 1:1, about 1.5:1, about 2:1, about 2.5:1, about 3:1, about 3.5:1, about 4: 1, about 4.5:1, or about 5:1. In some examples, the ratio of the organic stream to the aqueous stream is about 1.5-3.0:1 weight/weight.

[0072] After contacting the hemicellulose sugar stream with the LAEM, the resulting mixture can be separated into an organic stream (i.e., the organic phase) comprising the LAEM and at least one impurity and a refined hemicellulose sugar stream ( i.e. the aqueous phase). At least a portion of organic acids or inorganic acids (e.g., the acids used in the extraction of sugar from hemicellulose), and other impurities can be extracted into the organic stream. Surprisingly, the refining process can efficiently deal with added amounts of impurities resulting from sugarcane leaf hydrolyzate. In some examples, the sheets may contain at least about 1, at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, or at least about 7 times higher amounts of protein than that in pomace. The protein can hydrolyze to amino acids together with the saccharide polymer.

[0073] In some examples, the organic stream may be contacted with an aqueous stream in a countercurrent mode to recover any residual sugars absorbed into the organic stream. The organic stream may comprise LAEM, an organic acid, an inorganic acid, amino acids, and other impurities. The organic stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6% , less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.1%, less than 0.05%, less than 0.02%, or less than 0.01% weight/weight of hemicellulose sugars, such as 0.001% to 0.01% of hemicellulose sugars. The organic stream may comprise organic acids (such as acetic acid, formic acid, levulinic acid), inorganic acids (such as sulfuric acid), furfural, protein, amino acids, and ash. The organic stream may comprise at least about 0.05%, at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, at least about 0.9%, at least about 1 %, at least about 2%, at least about 3%, at least about 4%, or at least about 5% weight/weight organic acids, such as 0.1% to 3% organic acids. The organic stream may comprise at least about 0.05%, at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, at least about 0.9%, at least about 1 %, or at least about 2% weight/weight acetic acid, such as 0.1% to 1% acetic acid. The organic stream may comprise at least about 0.001%, at least about 0.002%, at least about 0.003%, at least about 0.004%, at least about 0.005%, at least about 0.006%, at least about of 0.007%, at least about 0.008%, at least about 0.009%, at least about 0.01%, at least about 0.02%, or at least about 0.05% weight/weight of formic acid, such as 0.001% to 0.05% formic acid. The organic stream may comprise at least about 0.001%, at least about 0.002%, at least about 0.003%, at least about 0.004%, at least about 0.005%, at least about 0.006%, at least about of 0.007%, at least about 0.008%, at least about 0.009%, at least about 0.01%, at least about 0.02%, at least about 0.05%, or at least about 0.1% weight/weight levulinic acid, such as 0.001% to 0.1% levulinic acid. The organic stream may comprise at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, at least about 0.9%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, or at least about 5% weight/weight inorganic acids, such as 0.1% to 3% inorganic acids. The organic stream may comprise at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, at least about 0.9%, at least about 1%, or at least about 2% weight/weight of sulfuric acid, such as 0.1% to 1% sulfuric acid. The organic stream may comprise at least about 0.05%, at least about 0.1%, at least about 0.2%, at least about 0.3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, at least about 0.9%, at least about 1 %, at least about 2%, at least about 3%, at least about 4%, or at least about 5% weight/weight furfurals, such as 0.1% to 3% furfurals. The organic stream may comprise at least about 0.001%, at least about 0.002%, at least about 0.005%, at least about 0.01%, at least about 0.02%, at least about 0. 3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, or at least about minus about 0.9% weight/weight methanol, such as 0.001% to 0.1% methanol. The organic stream may comprise at least about 1.0%, at least about 1.1%, at least about 1.2%, at least about 1.3%, at least about 1.4%, at least about about 1.5%, at least about 1.6%, at least about 1.7%, at least about 1.8%, at least about 1.9%, at least about 2.0 %, at least about 2.1%, at least about 2.3%, at least about 2.4%, or at least about 2.5% weight/weight of water-soluble lignin, such as 1 .5% to 2.5% water-soluble lignin. The organic stream may comprise at least about 0.001%, at least about 0.002%, at least about 0.003%, at least about 0.004%, at least about 0.005%, at least about 0.006%, at least about of 0.007%, at least about 0.008%, at least about 0.009%, at least about 0.01%, at least about 0.1%, or at least about 0.2%, weight/weight of amino acids, such as 0.001% to 0.2% amino acids. The organic stream may comprise at least about 0.01%, at least about 0.02%, at least about 0.03%, at least about 0.04%, at least about 0.05%, at least about 0.06%, at least about 0.07%, at least about 0.08%, at least about 0.09%, at least about 0.1%, at least about 0 .2%, at least about 0.3%, at least about 0.4%, or at least about 0.5% weight/weight ash, such as 0.01% to 0.3% ash . The organic stream may comprise 0.1% to 1% acetic acid, 0.001% to 0.05% formic acid, 0.001% to 0.1% levulinic acid, 0.1% to 1% sulfuric acid, 0. .1% to 3% furfural, 0.001% to 1% amino acids, and 0.01% to 3% ash. The organic stream may comprise 0.001% to 0.01% hemicellulose sugars, 0.1% to 3% organic acids, 0.1% to 1% acetic acid, 0.001% to 0.05% formic acid, 0.001% to 0.1% levulinic acid, 0.1% to 3% inorganic acids, 0.1% to 1% sulfuric acid, 0.1% to 3% furfural, 0.001% to 0.1% of methanol, 1.5% to 2.5% of water-soluble lignin, 0.001% to 0.2% of amino acids, and 0.01% to 0.3% of ash.

[0074] In some examples, the refined hemicellulose sugar stream comprises less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/weight of acid, such as 0.01 % to 3% weight/weight of acid. In some examples, the aqueous stream (refined hemicellulose sugar stream) may comprise less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100 ppm, less than 50 ppm, or less than than 10 ppm calcium, such as 10 ppm to 300 ppm calcium. In some examples, the refined hemicellulose sugar stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8% , less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight /weight of an amine having at least 20 carbon atoms, such as 0.01% to 4% of an amine. In some examples, the refined hemicellulose sugar stream may comprise less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8% , less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight /weight of an impurity, such as 0.1% to 4% of an impurity, in which the impurity is selected from ash, water-soluble lignin, furfural, fatty acids, organic acids, such as acetic acid and formic acid , mineral acids such as hydrochloric acid and sulfuric acid, furfural, hydroxymethylfurfural, methanol, proteins, amino acids, glycerol, sterols, rosin acid, and waxy materials. In some examples, the acid may not be recovered by distillation. Preferably, the LAEM does not comprise an additional oil-soluble organic acid other than the extracted acid composition.

[0075] The refined hemicellulose sugar stream may comprise less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than than 200 ppm, less than 100 ppm, or less than 50 ppm acetic acid, such as 50 ppm to 1500 ppm acetic acid. The refined hemicellulose sugar stream may comprise less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than 200 ppm , less than 100 ppm, or less than 50 ppm of formic acid, such as 50 ppm to 1500 ppm of formic acid. The refined hemicellulose sugar stream may comprise less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than 200 ppm , less than 100 ppm, or less than 50 ppm sulfuric acid, such as 50 ppm to 1500 ppm sulfuric acid. The refined hemicellulose sugar stream may comprise less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than 200 ppm , less than 100 ppm, or less than 50 ppm hydrochloric acid, such as 50 ppm to 1500 ppm hydrochloric acid. The refined hemicellulose sugar stream may comprise less than 700 ppm, less than 600 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm, less than 200 ppm, less than 100ppm, or less than 50 ppm furfural, such as 200 ppm to 600 ppm furfural. In some examples, the refined hemicellulose sugar stream comprises less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, or less than 0.1% weight/ ash weight, such as 0.1% to 4% ash. In some examples, the refined hemicellulose sugar stream comprises less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than than 200 ppm, less than 100 ppm, or less than 50 ppm nitrogen, such as 50 ppm to 1500 ppm nitrogen. In some examples, the refined hemicellulose sugar stream comprises less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than than 200 ppm, less than 100 ppm, or less than 50 ppm protein, such as 50 ppm to 1500 ppm protein. In some examples, the refined hemicellulose sugar stream comprises less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 800 ppm, less than 600 ppm, less than 400 ppm, less than than 200 ppm, less than 100 ppm, or less than 50 ppm of amino acids, such as 50 ppm to 1500 ppm of amino acids. The refined hemicellulose sugar stream may comprise 50 ppm to 1500 ppm acetic acid, less than 1500 ppm formic acid, 50 ppm to 1500 ppm sulfuric acid, less than 1500 ppm hydrochloric acid, 200 ppm 600 ppm furfural, less than 4% weight/weight ash, less than 1500 ppm nitrogen, less than 1500 ppm protein, and less than 1500 ppm amino acids. The refined hemicellulose sugar stream may comprise 0.01% to 3% weight/weight acid, 10 ppm to 300 ppm calcium, 0.01% to 4% of an amine, 0.1% to 4% of an impurity, 50 ppm to 1500 ppm acetic acid, less than 1500 ppm formic acid, 50 ppm to 1500 ppm sulfuric acid, less than 1500 ppm hydrochloric acid, 200 ppm to 600 ppm furfural, less than 4% weight/weight ash, less than 1500 ppm nitrogen, less than 1500 ppm protein, and less than 1500 ppm amino acids.

[0076] In some examples, the organic stream can be converted to the recycled LAEM stream. The recycled LAEM stream may comprise trilaurylamine, 2E1H, an organic acid, an inorganic acid, amino acids, and other impurities. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, maximum about 0.02%, maximum about 0.03%, maximum about 0.04%, maximum about 0.05%, maximum about 0.06%, maximum about 0.07%, maximum about 0.08%, maximum about 0.09% , or at most about 0.1% weight/weight organic acids, such as 0.001% to 0.1% organic acids. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, maximum about 0.02%, maximum about 0.03%, maximum about 0.04%, maximum about 0.05%, maximum about 0.06%, maximum about 0.07%, maximum about 0.08%, maximum about 0.09% , or at most 0.1% weight/weight acetic acid, such as 0.001% to 0.1% acetic acid. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, or maximum about 0.02% weight/weight of formic acid, such as 0.001% to 0, 01% formic acid. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, or maximum about 0.02% weight/weight of levulinic acid, such as 0.001% to 0.01% levulinic acid. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, maximum about 0.02%, maximum about 0.03%, maximum about of 0.04%, or at most about 0.05% weight/weight of inorganic acids, such as 0.001% to 0.03% of inorganic acids. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, or maximum about 0.02% weight/weight of sulfuric acid, such as 0.001% to 0.01% sulfuric acid. The recycled LAEM current may comprise a maximum of about 0.01%, a maximum of about 0.02%, a maximum of about 0.03%, a maximum of about 0.04%, a maximum of about 0.05 %, maximum approximately 0.06%, maximum approximately 0.07%, maximum approximately 0.08%, maximum approximately 0.09%, maximum approximately 0.1%, maximum approximately of 0.2%, a maximum of about 0.3%, a maximum of about 0.4%, or a maximum of about 0.5% weight/weight of furfurals, such as 0.05% to 0.3 % of furfurals. The organic stream may comprise at least about 0.001%, at least about 0.002%, at least about 0.005%, at least about 0.01%, at least about 0.02%, at least about 0. 3%, at least about 0.4%, at least about 0.5%, at least about 0.6%, at least about 0.7%, at least about 0.8%, or at least about minus about 0.9% weight/weight methanol, such as 0.001% to 0.1% methanol. The recycled LAEM stream may comprise at least about 1.0%, at least about 1.1%, at least about 1.2%, at least about 1.3%, at least about 1.4%, at least about 1.5%, at least about 1.6%, at least about 1.7%, at least about 1.8%, at least about 1.9%, at least about 2 .0%, at least about 2.1%, at least about 2.3%, at least about 2.4%, or at least about 2.5% weight/weight of acid-soluble lignin, such as 1.5% to 2.5% water-soluble lignin. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, maximum about 0.02%, maximum about 0.03%, maximum about of 0.04%, or at most about 0.05% weight/weight of amino acids, such as 0.001% to 0.03% of amino acids. The recycled LAEM stream may comprise a maximum of about 0.001%, a maximum of about 0.002%, a maximum of about 0.003%, a maximum of about 0.004%, a maximum of about 0.005%, a maximum of about 0.006%, at most maximum about 0.007%, maximum about 0.008%, maximum about 0.009%, maximum about 0.01%, maximum about 0.02%, maximum about 0.03%, maximum about of 0.04%, or at most about 0.05% weight/weight ash, such as 0.001% to 0.03% ash. The recycled LAEM stream may comprise 0.001% to 0.1% acetic acid, 0.001% to 0.01% formic acid, 0.001% to 0.01% levulinic acid, 0.001% to 0.01% sulfuric acid , 0.05% to 0.3% furfural, 0.001% to 0.03% amino acids, and 0.001% to 0.03% ash. The recycled LAEM stream may comprise 0.001% to 0.1% organic acid, 0.001% to 0.1% acetic acid, 0.001% to 0.01% formic acid, 0.001% to 0.01% levulinic acid , 0.001% to 0.03% inorganic acids, 0.001% to 0.01% sulfuric acid, 0.05% to 0.3% furfural, 0.001% to 0.1% methanol, 1.5% to 2.5% water-soluble lignin, 0.001% to 0.03% amino acids, and 0.001% to 0.03% ash.

[0077] The refined hemicellulose sugar stream can be further purified. For example, residual diluent in the refined hemicellulose sugar stream can be removed using a packed distillation column. Distillation can remove at least 70%, at least 80%, at least 90%, or at least 95% of residual diluent in the refined hemicellulose sugar stream. In some examples, the refined hemicellulose sugar stream may be contacted with a strong acid cation exchanger (SAC) (433) to remove residual metal cations and residual amines, then optionally contacted with a weak base anion exchanger (WBA). ) (434) to remove excess protons. Optionally, the refined hemicellulose sugar stream is purified using a distillation column (e.g., a packed distillation column), followed by a strong acid cation exchanger. In some examples, the refined hemicellulose sugar stream may be contacted with a weak base anion (WBA) exchanger to remove excess protons. The refined hemicellulose sugar stream can be pH adjusted, optionally after contacting the stream with a SAC exchanger and/or WBA exchanger. The refined hemicellulose sugar stream can be distilled or evaporated, then further polished by contact with a SAC resin, a WBA resin, and an MB resin, and, optionally, concentrated by evaporation. In some examples, the refined hemicellulose sugar stream may be evaporated (435) at 20-80% weight/weight dissolved sugars, such as 25-65% or 30-40% weight/weight dissolved sugars, thereby forming mode, a concentrated sugar solution (436). Evaporation can be conducted in any conventional evaporator, for example, a multiple effect evaporator, or a mechanical vapor recompression (MVR) evaporator.

[0078] The residual solvent present in the hemicellulose sugar stream or concentrated sugar solution can also be removed by evaporation. For example, a solvent that forms a heterogeneous azeotrope with water can be separated and optionally returned to the solvent cycle. Optionally, the refined hemicellulose sugar stream can be contacted with activated carbon to remove residual organic impurities. The refined hemicellulose sugar stream can also be contacted with a mixed bed resin system to remove any residual ions or color bodies.

[0079] The LAEM 431-A stream can be bottom extracted with an aqueous solution containing a base (e.g., sodium hydroxide, sodium carbonate, and magnesium hydroxide) (see, for example, process denoted in Fig. 4 by number 450). The base can be added as a suspension or aqueous solution. A portion of the solvent may be further purified using a lime solution (e.g., calcium oxide, calcium hydroxide, calcium carbonate, or a combination thereof) (see, e.g., process denoted in Fig. 4 by the number 460). , and the purified solvent can be recycled back to LAEM 431 extraction.

[0080] Optionally, prior to contacting the organic stream with a base 450, the organic stream 431-A is washed with water to recover any sugars in the stream to form a dilute solution of sugar and water. Typically, after washing, the organic stream 431-A may be less than 5%, 2%, 1%, 0.5%, 0.2%, 0.1%, or less than 0.05% of sugars, such as 0.1% to 2% sugars.

[0081] The base can be added as an aqueous solution or suspension. Optionally, the base is lime. The base may be a solution or suspension comprising lime, NaOH, Na2CO3, Mg(OH)2, MgO, or NH4OH. Optionally, the base concentration is about 1-20% weight/weight, preferably 4-10% weight/weight. Preferably, the base can produce a soluble salt after contacting acid in the acid-charged organic stream. Preferably, the base may be present in 2-10% excess over the stoichiometric equivalent of acid in the organic stream. The pH of the neutralized mixture can be between 5-8, such as pH 6-7. For example, the pH may be about 5.5, about 5.7, about 6.0, about 6.5, about 6.7, about 7.0, or about 7.5.

[0082] Contact of the organic stream with a base (e.g., bottom extraction) 450 can be carried out in any device, such as a centrifuge, a mixer-settler, stirred tanks, columns, or any other equipment suitable for this mode of bottom extraction. Preferably, the organic stream can be added to the base in a liquid-liquid separation centrifuge. Bottom extraction can result in the removal of at least 90% of the mineral acid, and at least 80% of the organic acid from the organic phase. In some examples, bottom extraction can remove at least 90%, such as at least 95%, of acids from the organic phase.

[0083] In some examples, a fraction of the organic stream, typically 5-25% of the total weight of the organic stream, may be separated for a deep cleaning process. The deep cleaning process may comprise contacting the organic stream with a base, such as sodium hydroxide, potassium hydroxide, and/or calcium oxide. The pH of the deep cleaning process may be at least 10, at least 11, at least 12, at least 13, or at least 14, such as 11 to 14. Optionally, this mixture comprising a fraction of the organic stream and base is combined with the remaining organic stream.

[0084] Optionally, bottom extraction 450 is carried out in multiple reactors. In one example, bottom extraction 450 is carried out in 4 reactors. In the first reactor, an amount of base equivalent to that of carboxylic acid can be added, and only the carboxylic acids can be extracted from the LAEM to produce a solution of the corresponding salts (e.g., sodium salt). In the second reactor, mineral acid can be extracted from the LAEM. The streams removed from each reactor can be treated separately to allow recovery of organic acids. Optionally, the aqueous streams taken from the bottom extraction steps can be combined. Typically, the combined stream may contain at least 3% mineral acid anion (e.g., sulfate ion if sulfuric and/or sulfurous acids were used in extracting sugar from hemicellulose 100), 0.2-3% acetic acid , and lower concentrations of other organic acids. The aqueous stream may contain a low concentration of the diluent, typically less than 0.5%, depending on the solubility of the diluent used in the water. Preferably, the aqueous stream removed from the bottom extraction can be maintained to allow segregation of chemicals present in these streams. In one example, Ca2+ and SO42-, which are harmful to anaerobic digestion, can be separately targeted for aerobic treatment.

[0085] The diluent can be removed from the aqueous phase by distillation. In some examples, the diluent may form a heterogeneous azeotrope with water that has a lower boiling point than the diluent alone, thus the energy required to distill the diluent is significantly reduced due to the vast excess of water over the diluent. diluent. Distilled diluent can be recovered and recycled for further use. The aqueous phase without diluent can be directed to the facility's waste treatment unit.

[0086] The organic stream, now neutralized after acid removal, can be washed with water to remove salts remaining from the bottom extraction. Optionally, the neutralized organic stream is washed with mixed extraction agents that can partially saturate with water, such as certain alcohols. The wash stream can be combined with the bottom extraction aqueous stream. In some examples, a fraction of the washed organic stream, typically 5-25% of the total weight of the organic stream, may be separated for the purification and filtration step (see also, process 460 in Fig. 4). The remaining organic stream (i.e., a second portion of a LAEM) can be recycled to the refining method denoted as 502 (referred to as LAEM extraction in Fig 5). The second portion of the LA-EM can be washed with water, thereby forming a washed LAEM. The portion of the washed organic stream (LAEM) may be less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, or less than 5% by weight of the washed organic stream, such as 10% to 25% by weight of the washed organic stream. The washed LAEM can be contacted with a second base. The pH of the base may be at least 10, at least 11, at least 12, at least 13, or at least 14, such as 11 to 13. The neutralized organic stream is also referred to herein as a second portion of a LAEM . During the continuous process of refining the lignocellulosic hydrolyzate, the second portion of a LAEM recovered from the neutralized mixture can be reused when it contacts the lignocellulosic hydrolyzate with a first portion of a LAEM. The continuous process may be repeated at least 20, at least 25, at least 30, at least 35, at least 40, at least 45, at least 50, at least 55, at least 60, at least 65, or at least 70 times in a day, such as 25 to 65 times a day. The volume of the second portion of a LAEM after repetition is at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 85%, at least about 90% or at least about 97% of the volume, such as 55% to 85% of the volume of the first portion of a LAEM before repetition.

[0087] The fraction separated for the purification step (504 in Fig. 5; process 460 in Fig. 4) can be treated with a suitable base, such as 5%, 10%, 15%, 20%, 25% weight /weight of lime, sodium hydroxide or potassium hydroxide mixture. The ratio of solvent to base suspension can be in the range of 1:1 to 10:1, such as 4:110:1, 4:1-5:1, 5:1-6:1, 6:1-7 :1, 7:1-8:1, 8:1-9:1, or 9:1-10:1. The treatment may be conducted in any suitable device, for example a thermostatic mixed tank. The solution may be heated for at least 1 hour at 60-100°C, such as 80-90°C. Base, such as lime, can react with residual organic acids and esters of organic acids, and organic adsorption impurities present in the organic phase, such as acidic soluble lignin and furfurals, as visualized by a color change from dark to light. The contaminated base and impurities can be filtered or centrifuged to recover the purified organic stream, which is washed with water and recycled back to the hydrolyzate refining process (502 in Fig. 5; process 431 in Fig. 4). The aqueous stream can be separated into other aqueous waste streams. Any solid cake that can be formed by the base reaction can be used in the waste water treatment plant as a neutralizing salt for waste acids, such as those produced from ion exchange regenerations.

[0088] The bottom extraction aqueous stream may contain salts of organic acids. This stream can be contacted with a cation exchanger to convert all salts into their respective organic acids (see, for example, the processes denoted as 505 in Fig. 5). Alternatively, organic acids can be converted to the acidic form by acidifying the solution with a strong mineral acid. The acidified stream can be distilled to collect formic acid and acetic acid (e.g., process 506 in Fig. 5). The remaining aqueous streams can be separated into residue.

[0089] In one aspect, the disclosure provides a system for refining a lignocellulosic hydrolyzate. In some examples, the system comprises (a) a hydrolyzate refining unit comprising a first inlet for receiving a lignocellulosic hydrolyzate stream, a second inlet for receiving a recycled LAEM stream, a first discharge for releasing an organic stream, and a second discharge for releasing an aqueous stream, and (b) a neutralization unit in fluid communication with the hydrolyzate refining unit, wherein the neutralization unit comprises an inlet for receiving the organic stream, and a second inlet for receiving a base, in which the neutralization unit is configured to convert the organic stream to the recycled LAEM stream, and further in which the neutralization unit comprises a first discharge for releasing the recycled LAEM stream into fluid communication with the second inlet. of the hydrolyzate refining unit.

[0090] The system may comprise a hydrolyzate refining unit, in which the hydrolyzate refining unit is configured to receive a stream of lignocellulosic hydrolyzate and a recycled LAEM, and in which the LAEM removes impurities from the stream. hemicellulose sugar to produce a refined hemicellulose sugar stream. Optionally, the lignocellulosic hydrolyzate stream is extracted with the LAEM against the current, for example, the lignocellulosic hydrolyzate stream flows in a direction opposite to the flow of the LAEM. The hydrolyzate refining unit may comprise a mixer-settler device, a stirred tank, a liquid-liquid separation centrifuge, a column, or a combination thereof. Optionally, the mixer-settler device, stirred tank, liquid-liquid separation centrifuge, or column, is equipped with a liquid feed device to receive the lignocellulosic hydrolyzate stream. The hydrolyzate refining unit may be a centrifuge, such as a liquid-liquid separation centrifuge. The hydrolyzate refining unit may comprise at least one liquid-liquid separation centrifuge, such as at least 2 liquid-liquid separation centrifuges. Optionally, the hydrolyzate refining unit comprises at least 2, at least 3, at least 4, or at least 5 liquid-liquid separation centrifuges. The hydrolyzate refining unit can be equipped with an inlet to receive the LAEM. Optionally, both mixtures of the hydrolyzate stream with the LAEM and separation stream can be conducted in a liquid-liquid separation centrifuge. In some examples, the hydrolyzate stream and the LAEM stream are premixed and fed to the centrifuge as a mixture through a single inlet. Liquid-liquid separation centrifuges are commercially available from several suppliers, including, for example, Rousselet Robatel Inc. and US Centrífuga Sistemas LLC. The refining unit can be maintained at any temperature at which the amine is soluble, such as 50-70°C. The ratio of the LAEM stream (organic stream) to the lignocellulosic hydrolyzate stream (aqueous stream) can vary from about 0.5:1 to about 10:1 weight/weight, such as about 3:1. about 3.5:1, about 4:1, about 4.5:1, about 5:1, about 5.5:1, or about 6:1. In some examples, the ratio of the organic stream to the aqueous stream is between about 3:1 to about 5:1 weight/weight. In some examples, the hydrolyzate refining unit may further comprise column or batch units for contacting the lignocellulosic hydrolyzate stream with ion exchange resins, or activated carbon to further polish the aqueous solution. In some examples, the second discharge of the hydrolyzate refining unit may be in fluid communication with a fermentation unit, in which the fermentation unit may be configured to convert sugars in the aqueous stream to fermentation products.

[0091] The hydrolyzate refining unit may be in fluid communication with a LAEM refining unit. The LAEM refining unit may comprise an inlet for receiving the organic stream. The LAEM refining unit may comprise a discharge to release an entrained sugar stream and a loaded organic stream. The LAEM refining unit may comprise a centrifuge or a static mixer, and a decanter centrifuge.

[0092] The neutralization unit may comprise a liquid-liquid separation centrifuge. The neutralization unit may comprise a mixing tank configured for an organic and base stream. The neutralization unit may be in fluid communication with a cleaning unit.

[0093] The cleaning unit may comprise an intake to receive at least 5% of the recycled LAEM stream. In some examples, the cleaning unit may be configured to contact the recycled LAEM stream with a base, thereby forming a mixture. The cleaning unit may comprise a flush to release the mixture into the neutralization unit.

[0094] The present systems and processes are designed to be used and carried out on industrially relevant scales. Processes described here for refining lignocellulosic hydrolyzates can be carried out using industrially available means and machines that can support high production rates at low cost, while maintaining high purification energy. A process of the present disclosure can be scaled up to a size that allows refining at least 1,000 tons of lignocellulosic hydrolyzate per year, or more. Optionally, this enables the production of at least 7,000 tons of purified xylose per year, or more.

[0095] A continuous process described herein may comprise at least 3 extraction steps: (i) extraction of mineral acid, organic acid and impurities by contacting the lignocellulosic hydrolyzate with a first portion of a liquid anion exchange medium (LAEM), and separating the contacted mixture into an aqueous stream and a charged organic stream; (ii) sugar entrained from bottom extraction from the charged organic stream by contacting the organic stream comprising the LAEM, acids and impurities with water, and separating the resulting mixture into an aqueous stream and a charged organic stream; and (iii) regeneration of the LAEM by contacting the charged organic stream comprising the LAEM, acids and impurities with a base solution or suspension, and separating the resulting mixture into an aqueous waste stream comprising the anions of the acids and impurities , and an organic stream comprising the regenerated LAEM. Reagents can be continuously recycled.

[0096] Each such step can be carried out in a liquid-liquid separation centrifuge. The liquid-liquid separation centrifuge may comprise a mixing section in the inlet, and a separation unit in the rotating section. Optionally, the liquid-liquid separation centrifuge is used in some, but not all, of the steps. The other steps can be carried out using different mixing and separation apparatus. Preferably, the step of contacting a lignocellulosic hydrolyzate can be conducted using a liquid-liquid separation centrifuge to provide high efficiency in high yield. Furthermore, this extraction can be done in a countercurrent mode. In other examples, this extraction may be achieved in a single-stage mode. Optionally, at least one line of the first extraction step, for example, at least 2 lines of the first extraction step, may feed a single line of the solvent recycle contacts. The second extraction step (i.e., sugar entrained in the bottom extraction) can be conducted in a liquid-liquid separation centrifuge. The second extraction step may be conducted by mixing the loaded organic stream with wash water in a static mixer, and separating in a centrifuge, for example, a decanter centrifuge. Optionally, the third extraction step (i.e., LAEM regeneration) is conducted by mixing the charged organic stream with a base suspension or solution in a mixing tank, and separating the mixture in a centrifuge, e.g., a centrifuge. liquid-liquid separation. Examples of industrial installations for refining lignocellulosic hydrolysates according to the disclosed methods are shown schematically in Figs. 7, 8 and 9.

[0097] Fig. 7 represents a schematic of an industrial production installation using only liquid-liquid separation centrifuges for all extraction steps. The feed hydrolyzate may be maintained in a feed tank 710, after separating the hydrolyzate from solids and counting the hydrolyzate with a strong acid cation exchange resin (SAC). Stream 711 can feed the hydrolyzate into two hydrolyzate refining units 701 and 702. Each hydrolyzate refining unit can also be fed with the organic stream 716 (i.e., the LAEM). The light phase, i.e. the organic phase loaded from both centrifuges, can be combined into a single stream 712, where it is optionally fed together with wash water in the LAEM refining unit 704 to the sugars entrained from the back extract. The aqueous stream 713, comprising refined sugar from both centrifuges 701 and 702, may be combined with the aqueous stream 714 to produce the running sugar solution which is sent for polishing and concentration as disclosed in PCT Application No. PCT/US2013 /039585 and PCT/US2016/012384, incorporated herein by reference. The hydrolyzate refining unit may be in fluid communication with a LAEM refining unit. The LAEM refining unit may comprise an inlet for receiving an organic stream. The organic phase from the hydrolyzate refining unit can be fed together with wash water into a LAEM refining unit for tail extract entrained sugars. The LAEM refining unit may comprise a discharge to release an entrained sugar stream and a loaded organic stream. The LAEM refining unit may comprise a centrifuge, or a static mixer, and a decanter centrifuge.

[0098] The organic stream 715 leaving the LAEM refining unit 704 can be sent to the neutralization unit 703, where it is mixed with an aqueous-based solution to neutralize the LAEM. The neutralization unit may comprise a liquid-liquid separation centrifuge. The neutralization unit may be in fluid communication with a cleaning unit. The aqueous phase removed from the neutralization unit 703 can carry the removed acids and impurities, and can be sent to the waste treatment part of the facility. The regenerated LAEM stream 716 can be sent back to centrifuges 701 and 702 for further use. The cleaning unit 720 may comprise an inlet for receiving at least 1%, 2%, 3%, 5%, 10%, 15%, 20%, or at least 25% of the recycled LAEM stream 716 that is separated from the 717. The cleaning unit can be configured to contact the recycled LAEM stream with a base, thereby forming a mixture. The cleaning unit may comprise a discharge for releasing the mixture of organic phase and aqueous phase, stream 721, into the neutralization unit 703, together with the stream 715.

[0099] Fig. 8 represents a schematic of an industrial production facility for performing extraction in a single-stage mode using liquid-liquid separation centrifuges. The hydrolyzate may be fed from the feed tank 810 via the stream 811 to the liquid-liquid separation centrifuges 801 and 802, where it is contacted with the organic stream 816 (i.e., the LAEM). After separation, the organic stream 812 may be mixed with wash water in a static mixer 831, and separated in a decanter centrifuge 832. The aqueous streams 813, from centrifuges 801 and 802, may be combined with the aqueous stream 814 from the decanter centrifuge to form the sugar stream which is sent for further polishing and concentration. The organic stream 815 can be sent to a neutralization tank 840, where it is mixed with an aqueous slurry or base solution. The resulting solution may be sent via stream 841 to the liquid-liquid separation centrifuge 803. The aqueous stream from the centrifuge 803 may comprise the removed acids and impurities, and may be sent to the waste treatment part of the plant. Organic stream 816 may comprise recycled LAEM. The recycled LAEM can be sent back to centrifuges 801 and 802 for additional extractions. Optionally, about 5%, 10%, 15%, 20%, 25% of the stream 816 is separated from the stream 817 and tank 820 for LAEM cleaning by contacting the organic stream with an aqueous-based solution. The mixture of organic and aqueous phases can be separated by stream 821 back to mixing tank 840, together with stream 815.

[00100] Fig. 9 represents a schematic of an industrial production facility for performing extraction in a countercurrent mode using liquid-liquid separation centrifuges. The hydrolyzate may be fed to a feed tank 910 via stream 911 to liquid-liquid separation centrifuges 901. The aqueous outflow stream 912 may be fed to liquid-liquid separation centrifuge 902. In a countercurrent mode, the centrifuge 2 may also be fed with recycled LAEM stream 942. The organic outflow stream 914 may be fed into the centrifuge 901. The loaded LAEM stream 915 may be fed into a static mixer 931. Along with wash water, The mixture may then be separated in a decanter centrifuge 932. The sugar comprising stream 933 may be mixed with a sugar comprising stream 913, and they may be sent for further product polishing and concentration. The organic stream 934, comprising the charged LAEM, may be mixed with a base solution or suspension in the neutralization tank 940. The mixture may be fed 941 into the liquid-liquid separation centrifuge 3. The aqueous outflow stream may be be sent to the waste treatment part of the facility. The regenerated LAEM stream 942 can be recycled back for further extraction. At least about 5%, 10%, 15%, 20%, or at least about 25% of the stream 932 can be separated from the stream 943 and tank 920 for LAEM cleaning by contact with a water-based solution. Optionally, the organic and aqueous phase mixture is separated by stream 921 back to mixing tank 940, along with stream 934. In certain aspects of the present disclosure, the aqueous solution or suspension fed into neutralization tank 920 or 940 may comprise an alkali metal oxide, alkali metal hydroxide, alkaline earth metal oxide, or alkaline earth metal hydroxide, or mixtures thereof. The aqueous solution may comprise a suspension of lime or NaOH, or a mixture thereof. Optionally, the base is added as an aqueous solution. Neutralization is controlled at a pH between 6 and 8. The neutralization pH may be controlled at a pH of at least about 6.0, at least about 6.1, at least about 6.2, at least about of 6.3, at least about 6.4, at least about 6.5, at least about 6.6, at least about 6.7, at least about 6.8, at least about 6 .9, at least about 7.0, at least about 7.1, at least about 7.2, at least about 7.3, at least about 7.4, at least about 7.5 , at least about 7.6, at least about 7.7, at least about 7.8, at least about 7.9, or at least about 8.0. Optionally, the aqueous solution or suspension fed into the solvent cleaning tank 920 comprises an alkali metal oxide, alkali metal hydroxide, alkaline earth metal oxide, or alkaline earth metal hydroxide, or mixtures thereof. The aqueous solution may be a suspension comprising lime or NaOH, or a mixture thereof. The solvent cleaning pH can be controlled at a pH of at least about 13.0, at least about 13.5, at least about 14.0, or at least about 14.5. Optionally, the pH of the LAEM cleanup is at least about 13.0, at least about 13.5, at least about 14.0, or at least about 14.5. The equivalent bases in LAEM cleaning excess can be used for LAEM neutralization.

[00101] LAEM can be recycled by contact with a base at very high efficiency. For example, during 365 days of continuous operation, only a maximum of about 0.5%, a maximum of about 1%, a maximum of about 1.5%, a maximum of about 2%, a maximum of about 2.5 %, maximum about 3%, maximum about 3.5%, maximum about 4%, maximum about 4.5%, maximum about 5%, or maximum about 5.5% of LAEM, such as 2% to 3.5% of LAEM can be lost to waste streams. The initial charge service life of the LAEM may be at least about 5 years, at least about 7 years, at least about 9 years, at least about 11 years, at least about 13 years, at least about 15 years old, at least about 17 years old, or at least about 19 years old, such as 5 years old to 11 years old. The service life of the LAEM may be at least about 5, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35 , or at least about 40 times, such as about 15 to 35 times that of a WBA that would have the same capacity for refining bagasse lignocellulosic hydrolysates. LAEM can be recycled at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about of 55, or at least about 60 times a day, such as 30 to 45 times a day. In some examples, the non-recoverable stream may be a maximum of 1%, a maximum of 5%, a maximum of 10%, a maximum of 15%, or a maximum of 20% of the total solvent stream, such as 5% to 15% of the total solvent stream. In another example, the amount of freshwater generated is at most about 0.5, at most about 0.55, at most about 0.6, at most about 0.65, at most about 0.7 , at most about 0.75, or at most about 0.8, such as 0.55 to 0.75, compared to the amount of fresh water generated by a WBA system of the same capacity when refining lignocellulosic hydrolysates of bagasse. The energy required for concentration of fresh water can be at most about 0.5, at most about 0.55, at most about 0.6, at most about 0.65, at most about 0.7, at most about 0.75, or at most about 0.8, such as 0.55 to 0.7, compared to the amount of energy required to concentrate freshwater generated by a WBA system of the same capacity when refining bagasse lignocellulosic hydrolysates. In another example, the amount of ash generated as a regeneration dump product from the LAEM weak base site may be a maximum of 0.05, a maximum of 0.1, a maximum of 0.15, a maximum of 0.2, at most maximum 0.25, maximum 0.30, maximum 0.35, or maximum 0.4, such as 0.15 to 0.30 compared to the amount of ash generated in the regeneration of a WBA system of the same capacity when refining lignocellulosic bagasse hydrolysates.

[00102] A system described herein may comprise a detection unit in fluid communication with the refining unit to analyze the refined aqueous stream. The detection unit can analyze the refined aqueous stream continuously or in batches. In some examples, the detection unit may comprise a pH probe. Optionally, if the pH probe detects that the pH of the refined aqueous stream is too acidic, such as pH less than about 3.0, the detection unit can separate the stream away from the fermentation unit. In some examples, if the pH probe can detect that the pH of the refined aqueous stream is too acidic, the detection unit is configured to raise the pH of the solution, for example, by adding ammonia. In some examples, the detection unit may analyze the color of the refined aqueous stream, for example, using a spectrophotometer. If the absorbance of light at a particular wavelength is determined to be very high, the detection unit can separate the stream away from the fermentation unit. In some examples, the detection unit may analyze the conductivity of the refined aqueous stream, for example, using a conductivity probe. If the conductivity is determined to be very high, such as conductivity greater than 10,000 μS/cm, the detection unit can separate the stream away from the fermentation unit. In some examples, the detection unit may analyze the density of the refined aqueous current, for example, using a refractometer. If the density is determined to be too high or too low, such as a density corresponding to a sugar concentration outside the range of 50 g/L to 300 g/L, the detection unit can separate the stream away from the fermentation unit. , or may cause the addition of water to dilute the current. The detection unit may be configured to analyze the concentration of one or more components of the refined aqueous stream, in which the one or more components are selected from xylose, arabinose, hexoses, glucose, galactose, mannose, fructose, disaccharides, oligosaccharides. , ash, phenolic compounds, furfural, and hydroxymethylfurfural. Any concentration outside the ranges described for the object methods and compositions may cause the detection unit to separate the stream away from the fermentation unit, or correct the concentration by appropriate concentration or dilution. Any stream separated from the fermentation unit can be further refined or used in some other process in the facility.

[00103] The acid-depleted hemicellulose sugar stream (i.e., the refined aqueous stream) can be further purified. For example, residual diluent in the acid-depleted hemicellulose sugar stream can be removed using a packed distillation column. Distillation can remove at least 70%, 80%, 90%, or 95% of the diluent, such as 80% to 85% of the diluent, in the acid-depleted hemicellulose sugar stream. With or without a diluent distillation step, the acid-depleted hemicellulose sugar stream can also be contacted with a SAC exchanger to remove any residual metal cations and any residual amines. Preferably, the acid-depleted hemicellulose sugar stream can be purified using a packed distillation column followed by a SAC exchanger. Preferably, the acid-depleted hemicellulose sugar stream can then be contacted with a WBA exchanger to remove excess protons. The amine-stripped and neutralized hemicellulose sugar stream may be adjusted to pH, and evaporated to 25-65% and preferably 30-40% weight/weight of dissolved sugars in any conventional evaporator, e.g. multiple effect, or a mechanical vapor recompression evaporator (MVR).

[00104] Any residual solvent present in the hemicellulose sugar stream can also be removed by evaporation. For example, solvent that forms a heterogeneous azeotrope with water can be separated and returned to the solvent cycle. Optionally, the concentrated sugar solution can be contacted with activated carbon to remove residual organic impurities. The concentrated sugar solution may also be contacted with a mixed bed resin system to remove any residual ions or color bodies. Optionally, the now refined sugar solution can be further concentrated by a conventional evaporator or MVR.

[00105] The resulting stream may be a highly purified hemicellulose sugar mixture (e.g., 436 in Fig. 4) comprising, for example, 85-95% weight/weight monosaccharides out of total dissolved sugars. The composition of sugars may depend on the composition of the starting biomass. A hemicellulose sugar mixture produced from softwood biomass may have 65-75% (w/w) C6 saccharides in the sugar solution out of total sugars. In contrast, a hemicellulose sugar mixture produced from softwood biomass can contain 8085% weight/weight C6 sugars out of total sugars. The purity of the stream in all cases can be sufficient for fermentation processes and/or catalytic processes using these sugars.

[00106] The highly purified hemicellulose sugar mixture 436 may be characterized by one or more, two or more, three or more, four or more, five or more, six or more characteristics including (i) monosaccharides in a proportion to sugars total dissolved > 0.50 weight/weight; (ii) glucose in a ratio to total mosaccharides < 0.25 weight/weight; (iii) xylose in a ratio to total monosaccharides > 0.18 wt/wt; (iv) fructose in a ratio to total monosaccharides < 0.10 wt/wt; (v) fructose in a ratio to total monosaccharides > 0.01 weight/weight; (vi) furfurals in amounts up to 0.01% weight/weight; (vii) phenols in amounts up to 500 ppm; and (viii) a trace amount of 2-ethyl-1-hexanol. For example, the sugar mixture may be a mixture having a high ratio of monosaccharides to total dissolved sugars, a low glucose content, and a high xylose content. The sugar mixture may be a mixture having a high ratio of monosaccharides to total dissolved sugars, a low glucose content, a high xylose content, and low impurity contents (e.g., low furfurals and phenols). The mixture may be characterized by a high ratio of monosaccharides to total dissolved sugars, a low glucose content, a high xylose content, low impurity contents (e.g., low furfurals and phenols), and a trace amount of 2- ethyl-1-hexanol.

[00107] The resulting stream can be a sugar mixture with a high monomeric proportion. In some sugar mixture, the ratio of monosaccharides to total dissolved sugars is greater than 0.50, 0.60, 0.70, 0.75, 0.80, 0.85, 0.90, or 0.95 weight/weight, such as 0.75 to 0.90 weight/weight. The aqueous stream (refined hemicellulose sugar stream) may comprise less than 14%, less than 12%, less than 10%, less than 8%, less than 6%, less than 4%, or less than 2% weight/weight arabinose, such as 6% to 12% arabinose relative to total dissolved sugars. The refined hemicellulose sugar stream may comprise less than 10%, less than 8%, less than 6%, less than 4%, or less than 2% weight/weight disaccharides, such as 4 % to 8% weight/weight of disaccharides, relative to total dissolved sugars. The resulting stream may be a sugar mixture having a low glucose content. In some sugar mixture, the ratio of glucose to total monosaccharides is less than 0.25, 0.20, 0.15, 0.13, 0.10, 0.06, 0.05, 0.03, or 0.02 weight/weight, such as 0.05 to 0.15 weight/weight glucose. Optionally, the resulting stream is a mixture of sugar with a high xylose content. In some sugar mixture, the ratio of xylose to total monosaccharides may be greater than 0.10, 0.15, 0.18, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80 or 0.85 weight/weight, such as 0.20 to 0.50 weight/weight of xylose.

[00108] In some 436 sugar mixtures, the ratio of fructose to total dissolved sugars may be less than 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0 .08, 0.09, 0.10, 0.15, 0.20, 0.25 or 0.30 weight/weight, such as 0.07 to 0.20 weight/weight. In some 436 sugar mixtures, the ratio of fructose to total dissolved sugars may be greater than 0.001, 0.002, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, or 0.09 weight/weight, such as 0.01 to 0.05 weight/weight.

[00109] The above hemicellulose sugar mixture may include a very low concentration of impurities (e.g., furfurals and phenols). In some resulting streams, the sugar mixture may have furfurals in an amount of up to 0.1%, 0.05%, 0.04%, 0.03%, 0.04%, 0.01%, 0.075%, 0.005 %, 0.004%, 0.002%, or 0.001% weight/weight, such as 0.01% to 0.04% weight/weight. In some resulting streams, the sugar mixture may have phenolic compounds in an amount of up to 700 ppm, 600 ppm, 500 ppm, 400 ppm, 300 ppm, 200 ppm, 100 ppm, 60 ppm, 50 ppm, 40 ppm, 30 ppm, 20 ppm, 10 ppm, 5 ppm, 1 ppm, 0.1 ppm, 0.05 ppm, 0.02 ppm, or 0.01 ppm, such as 30 ppm to 100 ppm. The hemicellulose sugar mixture may be further characterized by a trace amount of 2-ethyl-1-hexanol, for example, 0.01-0.02%, 0.02-0.05%, 0.05-0. .1%, 0.1%-0.2%, 0.2-0.5%, 0.5-1%, or less than 1, 0.5, 0.2, 0.1, 0, 05, 0.02, 0.01, 0.005, 0.002, or less than 0.001% weight/weight of 2-ethyl-1-hexanol.

[00110] This high purity sugar solution can be used to produce industrial products and consumer products as described in PCT/IL2011/00509 (incorporated herein by reference for all proposals). Furthermore, the softwood sugar product containing 65-75% w/w C6 sugars can be used as fermentation feed for species that are only capable of utilizing C6 sugars, and the resulting mixture of C5 and product can be separated. , the C5 can then be refined to obtain a C5 product, as described in PCT/US2011/50435 (incorporated herein by reference for all proposals).

[00111] A fermentation product may include at least one member selected from the group consisting of alcohols, carboxylic acids, amino acids, monomers for the polymer industry and proteins, and in which the method further comprises processing said fermentation product to produce a product selected from the group consisting of detergent, polyethylene-based products, polypropylene-based products, polyolefin-based products, polylactic acid (polylactide)-based products, polyhydroxyalkanoate-based products, and products polyacrylic based. These fermentation products can be used alone or with other components such as food or feed, pharmaceuticals, nutraceuticals, plastic parts or components to produce various consumer products, gasoline, gasoline, chemical additive, or surfactant.

[00112] High purity sugar solution products may be suitable for chemical catalytic conversions, as catalysts are usually sensitive to impurities associated with biomass and sugar degradation products. Typically, the purity may be greater than 95, 96, 97, 98%, preferably greater than 99, 99.5, or 99.9%. This product may comprise small amounts of tracer molecules, including, for example, residual diluent, for example, hexanol, 2-ethyl-1-hexanol, kerosene, or any other diluents used, as well as furfural, hydroxymethylfurfural, furfural or condensation products. of hydroxymethylfurfural, color compounds derived from caramelization of sugar, levulinic acid, acetic acid, methanol, galacturonic acid, or glycerol.

[00113] Once hemicellulose sugars are extracted, the remaining lignocellulosic stream can be subjected to cellulose hydrolysis to obtain an acid hydrolyzed cellulosic hydrolyzate stream and acid lignin stream. The acid cellulosic hydrolyzate stream can be refined using a LAEM as described herein to produce an aqueous stream comprising one or more cellulose sugars.

EXAMPLES

[00114] It is intended that the examples and embodiments described herein are for illustrative purposes only, and are not intended to limit the scope of the claimed invention. It is also understood that various modifications or changes in light of the examples and embodiments described herein will be suggested to the person skilled in the art, and are to be included within the spirit and scope of this application and the scope of the appended claims.

[00115] Example 1 - Bagasse extraction and refining: Bagasse sugar composition (DB4D01): Bagasse was crushed in a wood crusher. In a temperature-controlled tank, bagasse (60 lbs, dry basis) was then treated with an aqueous solution containing 0.5% H2SO4 (wt/wt) at a liquid to solid ratio of 14:2. The average temperature of the temperature-controlled tank was maintained at 130-135°C for 3 hours. The solution was circulated by pumping. The resulting liquor was collected and the solids washed with water. The wash water was then used to prepare the acid solution for the next batch by adding acids as needed. The lignocellulosic matter exhausted from hemicellulose was collected and dried.

[00116] The acidic hemicellulose sugar stream was moved through a SAC column. The sugar stream was then continuously extracted in a series of liquid-liquid separation centrifuges (2 stages countercurrent) with a LAEM having tri-laurylamine:2-ethyl-1-hexanol at a ratio of 30:70. The ratio of LAEM to sugar stream was maintained in the range of 2:1 to 1.5:1. The resulting aqueous phase was further purified using a SAC resin, a WBA resin, and a mixed bed resin. The pH of the resulting stream was adjusted to 4.5 with 0.5% HCl, and the sugar solution evaporated to a concentration of ~30% dissolved solids (DS). The resulting sugar stream contained about 7% arabinose, 2.5% galactose, 6.5% glucose, 65% xylose, 1.5% mannose, 4% fructose, and 14% oligosaccharides ( all % weight/total sugars). This sugar solution was further processed by fractionation in an SSMB system, resulting in a xylose-rich fraction and a xylose-depleted fraction. Each fraction was concentrated by evaporation. Table 1 provides a chemical analysis of the resulting xylose-rich sugar solution.

[00117] Table 1: Chemical analysis of a hemicellulose sugar mixture produced by extraction and purification of hemicellulose sugar from bagasse

[00118] Example 2 - Extraction of lignocellulosic hydrolyzate with 2-ethyl-1-hexanol: Careful design of the industrial plant to achieve high production of the refining sequence can be vital in order to achieve reasonable production rate and economy. A liquid-liquid separation centrifuge, such as the Rousselet model Robatel BXP 190, rated capacity 15 gpm, can be used. The Rotabel is a pilot-scale centrifuge, and can be scalable to industrial size.

[00119] The sugar stream was extracted continuously in a series of liquid-liquid separation centrifuges (2 stages countercurrent) with a LAEM having tri-laurylamine: 2-ethyl-1-hexanol at a ratio of 30:70. During extraction, contaminants diffuse across the interface of the organic and aqueous phases. Strong mixing can result in a large surface contact area. After diffusion has occurred, rapid phase separation can result in high throughput from the system. To achieve this, careful selection of the diluent and optimal mechanical means for mixing and separation may be necessary.

[00120] The extraction relief in the diffusion of contaminants through the interface of the two phases. As a result, it is preferable to create a larger surface by strong mixing. However, once diffusion occurs, it is desired to have rapid phase separation to allow high production in the system. These requirements can be optimized by selecting the organic phase and optimizing the mechanical means used for mixing and separation.

[00121] The single contact data in Table 2 shows that 2E1H, which is more hydrophobic, is less effective than hexanol in extracting impurities. This was studied on a number of typical impurities that can be found in the hydrolyzate. Table 2 shows that similar amounts of mineral acid were removed by organic phases comprising either hexanol or 2-ethyl-1-hexanol. However, the ability of 2E1H to remove organic acids and furfural from the hydrolyzate was limited. Total acidity was measured by titration of the aqueous phase, while specific acid species were quantified by HPLC. Sulfuric acid contributes to the majority of total acidity.

[00122] Table 2: Comparison of impurity removal using hexanol and 2-ethyl-1-hexanol

[00123] When conducting the process using the Robatel centrifuge, the relative hydrophobicity of hexanol results in a slow separation of the mixed solvents, and slow operation of the system. Surprisingly, 2-ethyl-1-hexanol has been found to be a more preferred diluent in a continuous process using a liquid-liquid separation centrifuge, such as the Robatel centrifuge described herein. As shown in Fig. 10, 2-ethyl-1-hexanol removes organic acids from the hydrolyzate more efficiently than hexanol in the continuous process. Not wishing to be bound by any particular theory, the greater hydrophobicity of 2-ethyl-1-hexanol is believed to contribute to improved performance in the continuous process. As a result, less solvent is entrained in the aqueous phase, resulting in better, more consistent performance. On an industrial scale, the continuous LAEM extraction process with 2E1H results in rapid separation of the organic and aqueous phases using less energy than would be required for acid removal processes typically used in the sugar refining industry.

[00124] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications can be made to them and are contemplated here. An embodiment of one aspect of the disclosure may be combined with or modified by an embodiment of another aspect of the disclosure. It is not intended that the invention(s) be limited by the specific examples provided within the specification. While the invention(s) has (or have) been described with reference to the above-mentioned specification, the descriptions and illustrations of the embodiments of the invention(s) herein are not significant to be construed in a sense of limitation. Furthermore, it should be understood that all aspects of the invention(s) are not limited to the specific representations, configurations or relative proportions set forth herein which depend on a variety of conditions and variables. Various modifications in the form and detail of embodiments of the invention(s) will be apparent to one skilled in the art. It is therefore contemplated that the invention(s) should also cover any such modifications, variations and equivalents.

Claims (64)

1. Method for refining a lignocellulosic hydrolyzate, the method characterized by the fact that it comprises: (a) providing at least 250 parts of the lignocellulosic hydrolyzate and 1 part of a liquid anion exchange medium (LAEM); (b) in a liquid-liquid separation centrifuge operating in a continuous process in countercurrent mode, contact at least a portion of at least 250 parts of the lignocellulosic hydrolyzate with 1 part of the LAEM; (c) separating at least a portion of the LAEM from the lignocellulosic hydrolyzate to form an aqueous stream comprising one or more sugars; and (d) repeating steps (b) and (c) until at least 250 parts of the lignocellulosic hydrolyzate have made contact with 1 part of the LAEM and at least 225 parts of the aqueous stream have been separated from the LAEM. 2. Method according to claim 1, characterized by the fact that the at least 250 parts comprises at least 1000 parts, and further in which the recovery of at least 225 parts comprises at least 900 parts. 3. Method according to claim 1, characterized by the fact that the at least 250 parts comprises at least 10,000 parts, and further in which the recovery of at least 225 parts comprises at least 9,000 parts. 4. Method, according to claim 1, characterized by the fact that the LAEM is periodically recycled. 5. Method, according to claim 1, characterized by the fact that the continuous process comprises steps of washing, neutralizing, and refining the LAEM portion. 6. Method according to any one of the preceding claims, characterized by the fact that at any given time, the ratio of the first portion of a LAEM to the lignocellulosic hydrolyzate is less than 5:1. 7. Method for refining a lignocellulosic hydrolyzate, the method characterized by the fact that it comprises: (a) contacting the lignocellulosic hydrolyzate with a first portion of a liquid anion exchange medium (LAEM) in a separation system comprising two separation centrifuges liquid-liquid fluidly coupled and operating in countercurrent mode to form a mixture; (b) separating the mixture in the liquid-liquid separation centrifuge into an organic stream and an aqueous stream, in which the organic stream comprises the LAEM, an acid and an impurity, and in which the aqueous stream comprises one or more sugars; (c) contacting the organic stream with a base, thereby forming a neutralized mixture; and (d) recovering a second portion of a LAEM from the neutralized mixture; in which steps (a) to (b) are a continuous process. 8. Method according to claim 7, characterized by the fact that steps (a) to (d) are a continuous process. 9. Method according to claim 7 or 8, characterized in that steps (a) to (d) are completed within 90 min. 10. Method according to any one of claims 7 to 9, characterized in that steps (a) and (b) are completed within 60 min. 11. Method according to claim 10, characterized in that steps (a) and (b) are completed within 30 min. 12. Method according to claim 11, characterized in that steps (a) and (b) are completed within 15 min. 13. Method according to claim 12, characterized in that steps (a) and (b) are completed within 5 min. 14. Method according to any one of claims 7 to 13, characterized by the fact that it further comprises washing the organic stream with water to remove residual sugar from the organic stream, thereby forming a dilute solution of sugar and water, and a washed organic stream. 15. Method according to claim 14, characterized by the fact that the diluted sugar and water solution is combined with the aqueous stream, in which the combined stream comprises at least 3.8% weight/weight of sugars. 16. Method according to any one of claims 7 to 15, characterized in that the base is added as an aqueous suspension or solution. 17. Method according to any one of claims 7 to 16, characterized by the fact that the base is lime. 18. Method according to any one of claims 7 to 16, characterized in that the base is added as an aqueous solution. 19. Method according to claim 18, characterized by the fact that the base is NaOH. 20. Method according to any one of claims 7 to 19, characterized by the fact that a pH of the neutralized mixture is between 6 and 7. 21. Method according to any one of claims 7 to 20, characterized in that it further comprises washing the second portion of a LAEM with water, thereby forming a washed LAEM. 22. Method, according to claim 21, characterized by the fact that it further comprises contacting a portion of the washed LAEM with a second base. 23. Method according to claim 22, characterized by the fact that the portion of the washed LAEM comprises less than 20% of the washed LAEM, and in which a pH of the base is at least 13. 24. Method according to any one of claims 7 to 23, characterized by the fact that it further comprises repeating steps (a)-(d), in which the second portion of a LAEM recovered in step (d) is reused in step (a) as the first portion of a LAEM when repeating steps (a)-(d). 25. The method of claim 24, wherein a volume of the second portion of a LAEM after repetition is at least 80% of the volume of the first portion of a LAEM before repetition. 26. Method according to claim 25, characterized by the fact that the volume of the second portion of a LAEM after repetition is at least 90% of the volume of the first portion of a LAEM before repetition. 27. Method according to claim 26, characterized by the fact that the volume of the second portion of a LAEM after repetition is at least 95% of the volume of the first portion of a LAEM before repetition. 28. Method according to claim 27, characterized by the fact that the volume of the second portion of a LAEM after repetition is at least 97.5% of the volume of the first portion of a LAEM before repetition. 29. Method according to any one of claims 24 to 28, characterized in that the method is repeated at least 45 times in a day. 30. Method according to any one of claims 7 to 29, characterized in that a proportion of the first portion of a LAEM to the lignocellulosic hydrolyzate is less than 5:1. 31. Method according to any one of the preceding claims, characterized in that the LAEM comprises an amine, in which the amine comprises at least 20 carbon atoms. 32. Method according to claim 31, characterized by the fact that the amine is a tertiary amine. 33. Method according to claim 32, characterized by the fact that the amine is tri-laurylamine. 34. Method according to any one of claims 31 to 33, characterized in that the LAEM additionally comprises a diluent. 35. Method according to claim 34, characterized in that the diluent comprises a C6-16 alcohol or kerosene. 36. Method according to claim 35, characterized in that the diluent is hexanol or 2-ethylhexanol. 37. Method according to claim 36, characterized by the fact that the diluent is 2-ethylhexanol. 38. Method according to any one of claims 34 to 37, characterized in that a ratio of the amine to the diluent is between 1:7 and 7:1 weight/weight. 39. Method according to any one of the preceding claims, characterized by the fact that the lignocellulosic hydrolyzate comprises at least 0.1% weight/weight of acid. 40. Method according to claim 39, characterized by the fact that the lignocellulosic hydrolyzate comprises at least 0.5% weight/weight of acid. 41. Method according to claim 39 or 40, characterized in that the acid comprises an inorganic acid and an organic acid. 42. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 200 ppm of calcium. 43. Method according to any one of the preceding claims, characterized in that the aqueous stream comprises arabinose in an amount of up to 12% weight/weight relative to total dissolved sugars. 44. Method according to any one of the preceding claims, characterized in that the aqueous stream comprises disaccharides in an amount of up to 8% weight/weight relative to total dissolved sugars. 45. Method according to any one of the preceding claims, characterized in that the aqueous stream comprises ash in an amount of up to 0.25% weight/weight. 46. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 1000 ppm of acetic acid. 47. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 1000 ppm of formic acid. 48. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 1000 ppm sulfuric acid. 49. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 1000 ppm of hydrochloric acid. 50. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 0.5% weight/weight of acid. 51. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises less than 0.1% weight/weight of acid. 52. Method according to any one of the preceding claims, characterized in that the aqueous stream comprises phenolic compounds in an amount of up to 500 ppm. 53. Method according to any one of the preceding claims, characterized by the fact that the aqueous stream comprises furfural in an amount of up to 500 ppm. 54. Method according to any one of the preceding claims, characterized in that the aqueous stream comprises nitrogen in an amount of up to 1000 ppm. 55. System for refining a lignocellulosic hydrolyzate, characterized by the fact that it comprises: (a) a hydrolyzate refining unit comprising: (i) two liquid-liquid separation centrifuges fluidly coupled; (ii) a first inlet for receiving a stream of lignocellulosic hydrolyzate, (iii) a second inlet for receiving a stream of recycled LAEM, (iv) a first discharge for releasing an organic stream, and (v) a second discharge for releasing an aqueous stream; and (b) a neutralization unit in fluid communication with the hydrolyzate refining unit, wherein the neutralization unit comprises an inlet for receiving the organic stream, and a second inlet for receiving a base, in which the neutralization unit is configured to convert the organic stream to the recycled LAEM stream by contacting the organic stream with the base, and further in which the neutralization unit comprises a first discharge for releasing the recycled LAEM stream into fluid communication with the second inlet of the hydrolyzate refining unit. 56. System according to claim 55, characterized in that the hydrolyzate refining unit further comprises a mixer-settler device, a stirred tank, a column, or a combination thereof. 57. System according to any one of claims 55 to 56, characterized by the fact that the hydrolyzate refining unit is in fluid communication with a LAEM refining unit, and further in which the LAEM refining unit comprises an admission to receive the organic current. 58. System according to claim 57, characterized by the fact that the LAEM refining unit comprises a discharge for releasing an entrained sugar stream and a loaded organic stream. 59. System according to claim 57 or 58, characterized in that the LAEM refining unit comprises a centrifuge or a static mixer and a decanter centrifuge. 60. System according to any one of claims 55 to 59, characterized in that the neutralization unit comprises a liquid-liquid separation centrifuge. 61. System according to any one of claims 55 to 60, characterized in that the neutralization unit comprises a mixing tank configured to mix the organic stream and the base. 62. System according to any one of claims 55 to 61, characterized by the fact that the neutralization unit is in fluid communication with a cleaning unit. 63. System according to claim 62, characterized by the fact that the cleaning unit comprises an inlet for receiving at least 5% of the recycled LAEM stream, and further in which the cleaning unit is configured to contact the recycled LAEM stream. LAEM is recycled with a base, thus forming a mixture. 64. System according to claim 63, characterized in that the cleaning unit comprises a discharge for releasing the mixture into the neutralization unit.