Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C3/00—Pulping cellulose-containing materials
  • D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07G—COMPOUNDS OF UNKNOWN CONSTITUTION
  • C07G1/00—Lignin; Lignin derivatives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08H—DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS
  • C08H6/00—Macromolecular compounds derived from lignin, e.g. tannins, humic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08H—DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS
  • C08H8/00—Macromolecular compounds derived from lignocellulosic materials
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C11/00—Regeneration of pulp liquors or effluent waste waters
  • D21C11/0007—Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C11/00—Regeneration of pulp liquors or effluent waste waters
  • D21C11/10—Concentrating spent liquor by evaporation

Definitions

• EP 2304058 Al described a process of decrystallization of cellulosic biomass with an acid mixture comprising phosphoric acid and sulfuric acid to enhance the enzyme digestibility of treated biomass.
• the document does not disclose any concept of recovery or recycle of phosphoric acid or sulfuric acid.
• MCC microcrystalline cellulose
• the present invention relates to a method for fractionating a lignocellulosic biomass, comprising the steps: a) providing a lignocellulosic biomass and pretreating said lignocellulosic biomass with phosphoric acid; b) exposing said pretreated lignocellulosic biomass to phosphoric acid for a defined period of time at a defined temperature range to dissolve cellulosic and/or hemicellulosic components of said biomass; c) quenching, within the same reaction vessel as for step b), the dissolution of said cellulosic and/or hemicellulosic components, by adding a first solvent to said lignocellulosic biomass, wherein said first solvent is water, an alcohol, an ether, a ketone or a mixture of any of the foregoing, thereby precipitating said cellulosic and hemicellulosic components as solids, d) separating said precipitated solid
• said evaporation in step e) occurs at a pressure ⁇ 1 bar and at a temperature below the boiling point(s) of said first and second solvent, preferably ⁇ 78°C , preferably in the range of from 20°C to 78°C.
• said water that is added in step f) has a temperature that is equal or higher than the temperature of said concentrated combined liquid fraction and that is in the range of from 20°C to 90°C.
• said concentrated phosphoric acid obtained in step h) is mixed with fresh concentrated phosphoric acid and is thereafter recycled in step i) as such mixture to be used in step a) and/or b).
• such fresh acid is used to cover losses in the acid recovery process.
• said flocculant is mainly an anionic flocculant.
• Various types of flocculants of anionic, cationic and non-ionic nature can be used.
• said flocculant is added in an amount of 0.05 wt.% - 2 wt.%, preferably 0.05 wt% -1 wt%, more preferably 0.1 wt% to 0.5 wt%, with reference to the weight of said concentrated combined liquid fraction.
• a preferred and useful concentration is 0.2 wt.% flocculant.
• said pretreating occurs for a time period of 1 min to 30 h, preferably 1 h to 5 h, and/or at a temperature in the range of from 0°C to 100°C, preferably 25°C to 60°C.
• the method according to the present invention further comprises the additional step: subjecting the solid crude lignin fraction of step g) to an acidic hydrolysis using water, preferably at a temperature in the range of from 50°C to 100°C, said acidic hydrolysis being optionally preceded by one or several washing steps using water said hydrolysis resulting in a solid fraction and a liquid fraction, separating said solid fraction and said liquid fraction from each other, washing the solid fraction and drying it, wherein said liquid fraction is an aqueous solution of sugars, including sugar monomers and oligomers, and said solid fraction is clean lig- nin.
• the residual acid in the solids makes the material acidic so, typically, the addition of water for the final hydrolysis results in an acidic hydrolysis.
• Embodiments of the method according to the present invention provide for a pretreatment of the lignocellulosic biomass with phosphoric acid, subsequent to which the thus pretreated lignocellu- losic biomass is exposed to phosphoric acid to dissolve cellulosic and/or hemocellulosic components. Thereafter, such dissolution is quenched in the same reaction vessel as for the previous step (i. e. where the dissolution took place), by adding an appropriate first solvent.
• the fact that the pretreatement with phospohoric acid, the exposure to phosphoric acid and the quenching take place in the same vessel, aheady is a substantial improvement over the prior art, where these steps were typically performed in separate vessels, thus adding to the complexity and logistics of the process.
• An appropriate first solvent may be water, an alcohol, an ether, a ketone, or a mixture of any of these.
• a typical example is ethanol.
• the cellulosic and hemicel- lulosic components will precipitate as solids, preferably amorphous solids.
• these precipitated solids, preferably amorphous solids can be separated from the liquid fraction present, and can be washed using a second solvent which also is water, an alcohol, an ether, a ketone or a mixture of any of the foregoing.
• the first and the second solvents are the same, i. e. both are water, an alcohol or an ether or a ketone.
• the first and the second solvent are ethanol.
• the second solvent which is used for washing is subsequently combined with the liquid fraction resulting from the quenching step, and this resultant "combined liquid fraction" comprises phosphoric acid, the first solvent and the second solvent and, additionally, lignin components dissolved in any of the aforementioned solvents.
• This "combined liquid fraction” is dark in colour and is also sometimes referred to herein as "black liquor”.
• the combined liquid fraction i. e. the "black liquor”
• Such evaporation is preferably performed at reduced pressure, i. e.
• a subsequent step water is added to such concentrated black liquor to precipitate at least part of the lignin components, in particular the crude lignin components, which have been dissolved in said concentrated combined liquid fraction.
• the dissolved lignin components precipitate. What results from this therefore is a precipitate of the lignin components and a dilute combined liquid fraction.
• Such "dilute combined liquid fraction” comprises phosphoric acid, and water and, possibly some biomass degradation products.
• the two components, i. e. the dilute combined liquid fraction and the precipitate of the lignin components are subsequently separated.
• the dilute combined liquid fraction is then concentrated by evaporation of the water.
• the method according to the present invention allows for an efficient recycling of both the phosphoric acid and of the first solvent and second solvent. Moreover, the yield of the overall process as well as the purity of the lignin recovered is exceptionally high.
• a fioc- culant is used in order to increase the precipitation of the lignin components dissolved in the combined liquid fraction (i. e. in the black liquor").
• the use of such flocculant not only increases the size of the lignin particles to facilitate the filtration efficiency, but also increases the lignin yield as well as the yield of the acid, when compared with a method using no flocculants. In addition to this, the use of flocculant increases the purity and decreases the viscosity of the recycled acid.
• the present invention also provides for a recycling of the first and second solvent obtained in the evaporation step e). Such first and second solvent is condensed and is subsequently recycled to be reused in steps c) and/or d). The efficiency of recycling can be further enhanced if the precipitated cellulosic solids of step d) having been washed using the second solvent, are further washed by water, and the resultant liquid fraction is collected. Such liquid fraction contains water, some first and second solvent and phosphoric acid.
• water washate This is also sometimes herein referred to as "water washate", and this can be further treated by evaporating the first and second solvent in a first step and by evaporating water in a second step. This will result in a clean fraction of first and/or second solvent, a clean water fraction and a clean concentrated phosphoric acid fraction.
• the resultant solids of such water washing step are cellulosic solids, and these can then be subjected to enzymatic (or other) hydrolysis, to produce sugars, either in monomeric or oligomeric form or in mixtures thereof, and these sugars can subsequently be subjected to fermentation.
• the flocculants that are used in embodiments of the present invention are manifold. They may be anionic, cationic or non-ionic.
• anionic flocculants are also preferred.
• poly- acrylamide flocculants in particular anionic polyacrylamide flocculants.Examples of the products tried are presented in Table 1.
• the use of a flocculant increases the yield of clean acid and of lignin.
• the flocculant samples were supplied by Nalco Inc for testing the suitability of the sample for crude lignin precipitation work. Table 1 below shows the applicability of various anionic and cationic flocculants on crude lignin precipitation work.
• the amount of flocculant doses, amount of water use, temperature of precipitation process have been optimized for both Nalclear® 7763 and Optimer® 9825.
• phosphoric acid is meant to include orthophosphoric acid as well as condensed polymeric forms thereof, such as pyrophosphoric acid and polyphosphoric acid, i.e. ⁇ ( ⁇ 0 2 ⁇ ) ⁇ ⁇ , where x is the number of P0 2 OH-units in the molecule.
• phosphoric acid also included in the term “phosphoric acid” are cyclic structures forming metaphosphoric acid molecules. This includes examples, such as trimetaphosphoric acid or cyclotriphosphoric acid, i.e. H 3 P 3 0 9 .
• the respective phosphoric acid anhydride compounds such as P 4 O 10 , often abbreviated as P 2 0 5 . Upon addition of water, such phosphoric acid anhydride will form phosphoric acid.
• ketone is meant to include compounds having a non-terminal carbon- yl group in their structure. Examples for a ketone are acetone, butanone, pentanone, methyl ethyl ketone and methyl isobutyl ketone.
• the ketones listed are not meant to be limiting rather to be descriptive of the potential to use any of a number of different ketones with various ketone structures that can be used to cause the precipitation of the polysaccharides.
• the first and second solvent contains no water or no more water than in a range of from 0.1 %(v/v) to 10 %(v/v).
• the second solvent is an alcohol, preferably ethanol, more preferably 90 %, 91 %, 92 %, 93 %, 94 %, 95 % or 96 % or 97 % or 98 % or 99 % (v/v) ethanol.
• steps a) - d) are performed without a separate addition of water.
• a situation is referred to wherein water is not added to the reaction as a separate solvent.
• a certain amount of water may be present in the reaction vessel(s) during steps a) - d), due to the possibly inherent water content of lignocellulosic biomass, i.e. such biomass itself containing some water and/or due to the first and/or second solvent possibly containing a small amount of water which is in the range of from 0.1 % (v/v) to 15 % (v/v), with reference to the amount of phosphoric acid, first or second solvent added, there is no separate addition of water.
• to quench is meant to refer to an action of a solvent which slows down, or halts a reaction. Such quenching is typically or in many instances also accompanied by a precipitation of some components.
• lignocellulosic biomass is meant to refer to a biomass which contains, inter alia, cellulose, hemicellulose, lignin, water extractives, ethanol extractives, acetic acid, phenolic compounds, free sugars (e.g. glucose and sucrose), inorganic minerals, resins, rosins, tannins, etc.
• the "lignocellulosic biomass” according to the present invention may be derived from different materials, selected from hardwood, softwood, paper, in particular recycled paper, waste paper, wood shavings, sawdust, forest trimmings, pulp, corn stover, corn cobs, corn
• water may refer to water which, optionally, has dissolved material in it, such as salts.
• reaction vessels include but are not limited to a reactor, a tank, preferably having at least one stirring device, more preferably having at least two stirring devices, a continuously stirred tank, a tubular reactor, a batch tank, a planetary mixer, a double arm kneader, a continuous kneader or an extruder.
• the term "configured to receive a solvent from a container”, as used herein is meant to refer to an arrangement, wherein a reaction vessel or separation vessel is adapted to receive a solvent from a solvent container. In one embodiment, such solvent container is connected to the reaction vessel/separation vessel by an appropriate pipe, such as a tubing etc.
• the methodology according to the present invention results, inter alia, in cellulose, hemicellulose and lignin. Furthermore, the methodology according to the present invention has a stream of phosphate as phosphoric acid as a possible product.
• the cellulose as well as the hemicellulose can be further processed to result in sugars, for example xylose and glucose.
• the stream of phosphate is typically recycled to be re-used again in steps a) and b), as outlined above, but can, if desired, also be converted into a fertilizer component.
• the lignin that results from the methodology according to the present invention can be further used in various applications, outlined further below.
• xylose as an example of a hemicellulosic-sugar, this is a sugar that was first isolated from wood and hence named for it.
• Xylose is classified a monosaccharide of the aldo- pentose type, which means that it contains five carbon atoms and includes a formyl functional group. It is the precursive to hemicellulose, one of the main constituents of ligno cellulosic bio- mass. Like most sugars, it can adopt several structures depending on conditions. With its free carbonyl group, it is a reducing sugar.
• the acid catalyzed degradation of hemicellulose provides xylose which can be dehydrated to form furfural, a specialty solvent in industry and a precursor to synthetic polymers.
• Xylose is not metabolized by humans. It is absorbed unchanged from the gut, and excreted by the kidneys.
• xylose In animal medicine, xylose is used to test for mal-absorption by administration in water to the patient after fasting. If xylose is detected in blood and/or urine within the next few hours, it has been absorbed by the intestines. Reduction of xylose by catalytic hydrogenation produces the non-cario genie sugar substitute xylitol.
• Xylose - as a sweetener - its use as a sweetener directly is very limited, however, once hydro- genated either chemically or biologically it becomes xylitol which is used as a low glycemic in- dex non-cariogenic sweetener.
• the actual market for xylitol is actually not very large and can be flooded by xylitol made by chemically hydrogenating xylose from China very quickly.
• Xylitol is a sweetener that can be made chemically by hydrogenation of xylose or via fermentation of xylose using a xylitol producing organism. There are a number of naturally occurring organisms that produce xylitol from xylose.
• the present invention may result in cellulosic-sugars.
• Such cellulosic-sugars can be converted into platform molecules through fermentation or chemical transformation.
• Ethanol is probably the most studied chemical from bio-conversion of sugars. Its uses in bio-fuel or in the production of ethylene are the largest potential market for this molecule.
• Di-acids are another type of chemicals that has a high potential for both commodity and specialty chemicals.
• succinic acid can be converted in a variety of other chemicals such as 1,4-butanediol or tetrahydrofuran that are building blocks for the production of fibers, polymers or solvents.
• lignin resulting from the present invention may be used as:
• the methodology according to the present invention also has a stream of phosphate as phosphoric acid as a by-product.
• the phosphoric acid typically is recycled from the backend of the process to be used in steps a) and b) again, but, alternatively may also be converted to a fertilizer component.
• the acid can be neutralized with an appropriate base to provide a good fertilizer component.
• Bases might include NaOH, KOH, NH40H, Ca(OH)2, Mg(OH)2, and the carbonates for instance of all of the aforementioned materials.
• This invention for the first time, enables the acid and solvent recovery and recycling aspects of the COSLIF based biorefinery.
• most of the 2 nd generation industries are designed to burn the crude lignin to generate energy in absence of any credible and economic process of isolation and purification for application in value added product development.
• Figure 1 shows a block flow diagram describing the recovery of phosphoric acid and of lignin according to an embodiment of the present invention, without the use of a flocculant.
• Figure 2 shows a block flow diagram describing the purification of lignin according to an embodiment of the present invention, without the use of a flocculant,
• Figure 3 shows a block flow diagram describing biomass pretreatment and fractionation conditions
• Figure 5 shows a block flow diagram describing the purification of lignin according to an embodiment of the present invention involving the use of a flocculant
• Figure 7 shows a flow diagram describing the chemical recovery processes from the water wash of the precipitated cellulosic solids in accordance with an embodiment of the present invention.
• An embodiment of the process in accordance with the present invention includes processing of biomass for size reduction, concentrated phosphoric acid treatment of biomass at temperature ranging from 30 to 70 °C for 40 to 80 min, followed by quenching of the reaction and washing of the pretreated solid with ethanol, followed by washing with water before sending the acid and ethanol free solid mass to hydrolysis, preferably enzymatic hydrolysis, and fermentation process.
• the quenching and ethanol washing steps generate a stream called "black liquor", whereas the water wash steps generate another stream called water washate.
• Black liquor consists of phosphoric acid, ethanol, some water, biomass derived products and extractives.
• the water washate contains ethanol, water, acid and sugar in monomelic and oligomer form. It is important to recover phosphoric acid, ethanol, and biomass derived products from black liquor to make the whole process economically viable. Most of the used phosphoric acid is in black liquor, significant amount in water washate and very small quantity in washed pretreated biomass.
• a process has been developed to separate phosphoric acid from black liquor and purify to a level suitable for reuse in biomass pretreatment process.
• the black liquor was evaporated to collect ethanol as condensate and the residual concentrated black liquor is then mixed with four times of water on a mass basis for precipitation of crude lignin
• the precipitated particles are very small (about ⁇ 5 ⁇ ).
• the precipitated solid particles are separated by centrifuge and washed with water to remove residual acid along with some water soluble materials.
• the liquid fraction from solid- liquid separation was concentrated to get an acid stream of 85% strength to be reused in pretreatment process.
• the precipitated lignin was further purified by hy- drolyzing it in acidic medium and by solid/liquid separation and washing.
• the crude lignin will undergo a mild acidic hydrolysis process to facilitate the conversion of carbohydrate to mono- meric sugar.
• the lignin is maintained as a solid. Following the solid liquid separation, the aqueous sugar solution will go to fermentation process or depending on the sugar concentration, it might be cycled back to water washing with no or minimal additional work.
• the lignin will be dried for potential use to prepare value added products.
• the black liquor generated through ethanol quenching of the reaction and ethanol washing of residual solid will typically consist of phosphoric acid, ethanol, water and biomass degradation products such as lignin, C5 and C6 monomeric sugars and oligomers, extractives, and other soluble organic and inorganic materials.
• the black liquor will then go through an evaporation process where ethanol is removed and passed through a condenser yielding ethanol of 90 to 95% purity.
• the evaporation process was performed in a rotavapor at temperature in the range of 30 to 75 0 C under vacuum at around 15 mbar.
• the block flow diagram of acid and lignin purification has been shown in Figure 1.
• This black liquor will then be mixed with water, with water to concentrated black in the ratio of 2:1 to 10:1 as weight percent. This addition of water causes the lignin and minor amounts of carbohydrate to precipitate. Basic compounds were avoided to minimize any salt formation in the acid allowing for more complete recovery.
• the particle size of the precipitates is typically in the range of 0.4 to 5 micron.
• the solid-liquid separation is performed using a centrifuge only since the very small size precipitates passed through and/or blocks the pore to slow the filtration.
• the filtrate from the solid liquid separation is dilute phosphoric acid, whereas the precipitate is crude lignin along with residual acid, oligomers, carbohydrates, inorganic etc.
• the precipitates then undergo a water wash to recover some residual acid.
• the washed acid is then added to the dilute acid stream before going to the evaporator to remove water to produce concentrated acid.
• the dilute acid was evaporated in rotavapor at around 60 to 90 °C under vacuum at 15 mbar to remove water.
• the strength of the recovered acid is around 91% well above the fresh acid of 85% strength.
• This recovered acid after diluting to 85% strength level can be used in the biomass pretreatment step(s) (i.e. steps a) and/or b)).
• the washed crude lignin is then going to an autohydrolysis process at 100 0 C for two hrs. After cooling down, the mass undergoes a solid/liquid separation and washing step. The solid residue is the purified lignin.
• the filtrate will contain mainly sugar and some soluble materials.
• the crude lignin compositional analysis shows the presence of ash, the majority of which comes from acid as P 2 0 5 .
• the recovered acid was processed at 91% strength, well above 85% strength as required in bio- mass pretreatment. However, it was not possible to remove all small size, e.g. micron size particles by centrifuge or by other filtration method. As a result, the concentrated recovered acid according to this embodiment still contains a significant quantity of micron size black particles that makes the recovered acid black in color and of higher viscosity than that of fresh phosphoric acid.
• the viscosity of "fresh", i.e. pristine, i.e. unused, i.e. freshly manufactured, acid is 47 cSt, whereas for recovered acid it is 56.6 cSt in accordance with this embodiment of the present invention.
• the need to find some method to transform the small particles into larger particles and to remove all the solid particles to get relatively clean recovered acid with strength greater than 85%o and of viscosity similar to pristine acid is addressed further below.
• the recycled acid obtained following embodiments of the method according to the present invention has been applied in the pretreatment of biomass and compared with that of fresh acid as well as mixed acid containing 50% recycled acid and 50%> fresh acid.
• the pretreatment condition, washing condition and pretreatment yield has been presented in Table 3.
• Table 3 Biomass pretreatment condition, washing requirement and biomass yield.
• the concentrated black liquor is treated with a flocculant, preferably an anionic flocculants more preferably an anionic flocculants solution.
• a flocculant preferably an anionic flocculants more preferably an anionic flocculants solution.
• Pursuant to such treatment the quantity of solid fraction and the size of the particle are significantly higher than those obtained by precipitating with water only.
• the solid/liquid separation can easily be performed by using filter paper of pore size 25 micron under vacuum.
• the crude lignin was then washed one time with water to remove residual acid.
• the crude lignin still containing some acid will undergo a mild acidic hydrolysis process to facilitate the conversion of carbohydrate to monomeric sugar.
• the lignin is maintained as a solid and separated from aqueous solution by filtration.
• the black liquor generated through ethanol quenching of the reaction and ethanol washing of residual solid will typically consist of phosphoric acid, ethanol, water and biomass degradation products such as lignin, C5 and C6 monomeric sugars and oligomers, extractives, and other soluble organic and inorganic materials.
• the black liquor will go through an evaporation process where ethanol is removed and passed through a condenser yielding ethanol of 90 to 95% purity.
• the evaporation process was performed in a rotavapor at temperature range 30 to 60 0 C under vacuum at around 15 mbar.
• the filtrate from the solid liquid separation is dilute phosphoric acid, whereas the precipitate solid is crude lignin along with residual acid, oligomers, carbohydrates, inorganic etc.
• the precipitate is then undergoing a water wash to recover some residual acid.
• the washed acid is then added to the dilute acid stream before going to the evaporator to remove water to produce concen- trated acid.
• the dilute acid was evaporated in a rotavapor at around 70 to 90 C under vacuum at 15 mbar.
• the strength of the recovered acid is around 91% well above the fresh acid of 85% strength. This recovered acid after diluting to 85% strength level as required by pretreatment condition can be used in the biomass pretreatment step a) or the exposure step b).
• the recovered acid was processed at 91% strength, well above 85%) strength as required in biomass pretreatment.
• the recovery rate of clean acid is about 94% of the acid used in pretreatment process.
• the remaining 6% might end up in the filtrate from lignin separation, water wash and small quantity in washed solid residue.
• the color of the recovered acid is lighter than that of recovered acid processed without using flocculants during precipitation of lignin.
• the washed crude lignin is then going to an autohydrolysis process at 100 0 C for two hrs. After cooling down, the mass undergoes a solid/liquid separation and washing step. The solid residue is the purified lignin. The filtrate will contain mainly sugar and some soluble materials.
• the crude lignin compositional analysis shows the presence of ash, majority of which coming from acid as P 2 0 5 .
• the following compositional analysis presented in Table 3 for washed crude lignin, and hydrolyzed and washed lignin indicate that the washed lignin contains carbohydrate and ash in addition to lignin.
• the hydrolysis of washed crude lignin without addition of any acid should convert most of the carbohydrate into monomer sugar. Through the washing of hydrolyzed material, all sugars and any residual acid go into the aqueous phase leaving behind the purified lignin.
• the compositional analysis of purified lignin shows complete removal of ash but contain significant quantity of sugar, especially xylose. This might be due to incomplete hydrolysis of carbohydrate and/or good washing. This problem can be solved by simply extending the hydrolysis time and improved washing. .
• Table 4 Compositional analysis of water washed crude lignin and hydrolyzed & washed purified lignin.
• biomass pretreatment and fractionation conditions for the embodiments using a flocculant are the same as shown in figure 3.
• the inventors believe that the recovery of increased amount of lignin and clean acid is due to the formation of large agglomerated crude lignin precipitate with a flocculant suitable for better solid/liquid during filtration in comparison when no flocculant is used.
• the clean lignin content is 1.5% higher than that of when no flocculant is used.
• Table 6 Comparison of product recovery combined from black liquor and water wash with and without flocculant use.
• the block-flow diagrams in Figure 6 shows the lignin purification process when a flocculant is used in lignin precipitation.
• the bock flow diagram in Figure 7 shows the recovery process of acid and ethanol from a water wash of the cellulosic solids.
• the biomass is mixed with the phosphoric acid (85%) and allowed to sit or soak for 1 to 5 hours. For the acid recovery and recycle work 1 hour presoak was used. Once the presoak period is completed, the acid and biomass is transferred into the reactor (Charles Ross and Sons 200 gallon planetary mixer). The mixture is heated to 70 °C and held at this temperature for 1 hour. At the end of the reaction period the reaction is quenched with 400 Kg of ethanol. Because the acid dissolves the biomass, the quench process actually causes the cellulose and hemicellulose to precipitate as solids (cellulosic solids). The lignin fraction remains soluble in the acid and ethanol solution.

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