WO2011151823A1

WO2011151823A1 - Lignin compositions, systems and methods for processing lignin and/or hcl

Info

Publication number: WO2011151823A1
Application number: PCT/IL2011/000424
Authority: WO
Inventors: Aharon Eyal; Robert Jansen; Asher Vitner; Revital Mali
Original assignee: Hcl Cleantech Ltd.
Priority date: 2010-06-03
Filing date: 2011-06-01
Publication date: 2011-12-08
Also published as: EP2609104A1; WO2011151823A8; BR112012030819A2

Abstract

A lignin composition including: (a) lignin; (b) water; and (c) a first organic solvent (SI) less than 15% soluble in water and characterized by at least one of: (i) a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa; and (ii) a hydrogen-bond related component of Hoy's cohesion parameter (delta-H) between 5 and 20 MPa. Methods and systems employing such compositions are also disclosed.

Description

[GNIN COMPOSITIONS, SYSTEMS AND METHODS FOR PROCESSING LIGNIN

AND/OR HCL

FIELD OF THE INVENTION

This invention relates to processing of lignin generated by acid hydrolysis of lignocellulosic substrates.

BACKGROUND OF THE INVENTION

The carbohydrate-conversion industry is large and rapidly increasing in size. Currently, about 100 million tons of carbohydrates are fermented annually to provide fuel- grade ethanol and this number is predicted to triple in the next decade.

Millions of tons of carbohydrates are also fermented every year to provide food and feed products, such as citric acid and lysine. Also large and increasing is fermentation to produce other products, such as monomers for the polymer industry, e.g. lactic acid for the production of polylactide

Carbohydrates are an attractive and environment-friendly substrate since they are obtained from renewable resources. For example sucrose can be produced from sugar canes and glucose can be produced from corn and wheat starches. In addition, the amount of land which would be need to grow sufficient amounts of these sugar crops to support large scale fermentation products would be cost prohibitive.

However, sugar cane, corn and wheat are produced primarily for human consumption and/or as livestock feed. Increased consumption by industry may impact food costs.

As an alternative, many renewable non-food resources are potential sources of soluble carbohydrates. The renewable non-food resources can generally be described as "woody materials" or "lignocellulosic materials". These lignocellulosic materials include, but are not limited to, wood and by-products of wood processing (e.g. chips, sawdust, and shavings) as well as residual plant material from agricultural products and paper and paper industry byproducts (e.g. cellulose containing residues and/or paper pulp)

Residual plant material from agricultural products includes processing by-products and field remains.

Processing by-products includes, but is not limited to, corn cobs, sugar cane bagasse, sugar beet pulp, empty fruit bunches from palm oil production, straw (e.g. wheat or rice), soy bean hulls, residual meals from the vegetable oil industry (e.g. soybean, peanut, corn or rapeseed), wheat bran and fermentation residue from the beer and wine industries.

Field remains includes, but is not limited to, corn stover, post harvest cotton plants, post harvest soybean bushes and post harvest rapeseed plants.

Lignocellulosic materials also include "energy crops" such as switch grass and broom grass which grow rapidly and generate low-cost biomass specifically as a source of carbohydrates.

These lignocellulosic carbohydrate sources contain cellulose, hemicellulose and Iignin as their main components and also contain mineral salts (ashes) and lipohilic organic compounds, such as tall oils. The degree and type of theses non-carbohydrate materials can create technical problems in production of soluble carbohydrates.

Lignocellulosic materials typically contain 65-80% cellulose and hemicelluloses on a dry matter basis. Cellulose and hemicellulose are polysaccharides which can release carbohydrates suitable for fermentation and/or chemical conversion to products of interest if they are hydrolyzed. Lignin is typically resistant to acid hydrolysis.

Hydrolysis of hemicellulose is relatively easy, but hydrolysis of cellulose (typically more than 50% of total polysaccharides) is more difficult due to its partial crystalline structure.

In order to realize useful carbohydrates from these potential sources in an industrial context, production costs must be considered, relative to similar costs using food derived carbohydrates. Alternatively or additionally, processing should consider a level of production of green-house gases.

Although conversion of lignocellulosic material to carbohydrates via enzyme- catalyzed and/or acid-catalyzed hydrolysis of polysaccharides and pyrolysis of lignocellulosic material have been previously described, industrial scale application of the proposed technologies has presented technical problems which remain to be overcome.

Potential downstream applications of soluble carbohydrates include, but are not limited to, production of bio-fuels (e.g. ethanol, butanol or hydrocarbons), use in the food industry (e.g. fermentation to citric acid or xanthan gum and conversion of xylose to xylitol for use as an artificial sweetener) and industrially useful monomers.

As new processes are developed for the production of alternative fuels such as fatty acid esters and hydrocarbons (directly formed by fermentation or produced by conversion of fermentation products), the demand for soluble carbohydrates is expected to increase. Acid hydrolysis of a lignocellulosic substrate using strong acids (e.g. sulfuric acid or hydrochloric acid (HQ) forms a liquid hydrolyzate containing solublecarbohydrates, contaminants soluble in aqueous acid solution and the acid. Typically, the acid is diluted to some degree by release of moisture from the substrate. Since lignin present in the substrate does not hydrolyze and stays essentially insoluble, the acid hydrolysis also produces lignin dispersed in, or wetted by, an aqueous solution of acid (e.g. HC1).

A primary industrial use of lignin is currently combustion as fuel. It is estimated that approximately 70 million tons of Lignin are burned each year. Much of this material is presently available as dried Kraft black liquor from the paper industry. Lignin is more energy rich than wood on a dry matter basis.

SUMMARY OF THE INVENTION

A broad aspect of the invention relates to increasing efficiency of commercial scale acid hydrolysis of lignocellulosic material employing HC1. According to various exemplary embodiments of the invention this efficiency contributes to a reduced cost and/or an increased yield of desired soluble carbohydrate (i.e. sugar) products. Alternatively or additionally, this efficiency contributes to an increased degree of purity of lignin produced as a byproduct of the hydrolysis. Optionally, this increased degree of purity contributes to an increase in a commercial value of the lignin which, in turn, improves the economics of producing the primary carbohydrate product. Alternatively or additionally, acid hydrolysis of lignocellulosic substrates produces about 80% less greenhouse bases than fermentation of corn to produce a similar amount of carbohydrates.

One aspect of some embodiments of the invention relates to compositions containing Lignin, water and a solvent (SI). Optionally, at least some of the lignin is present as solid lignin. These compositions are useful in various methods described hereinbelow and contribute to solution(s) of one or more technical problems described hereinbelow.

According to various exemplary embodiments of the invention these compositions may also include HC1 and/or carbohydrates.

In some exemplary embodiments of the invention, the carbohydrates include one or more of glucose, mannose, xylose, galactose, arabinose and oligosaccharides less than 11 sugar units in length (i.e. DP<11).

In some exemplary embodiments of the invention an "SI" solvent is employed. Throughout this specification and the accompanying claims "SI" refers to, an organic solvent (in some embodiments a "first" organic solvent) which is less than 15% soluble in water and has a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa^{1 2} and/or a hydrogen-bond related component of Hoy's cohesion parameter (delta-H) between 5 and 20 MPa^1/2. Optionally, SI includes an alcohol, ketone or aldehyde with 5, optionally 6, or 8 or more carbon atoms. Optionally, SI includes a hexanol, a heptanol or an ocatnol such as 2-ethyl-hexanol and combinations thereof.

Delta-P is the polarity related component of Hoy's cohesion parameter and delta-H is the hydrogen bonding related component of Hoy's cohesion parameter.

The cohesion parameter, as referred to above or, solubility parameter, was defined by Hildebrand as the square root of the cohesiv energy density:

where AEvap and V are the energy or heat of vaporization and molar volume of the liquid, respectively. Hansen extended the original Hildebrand parameter to a three-dimensional cohesion parameter. According to this concept, the total solubility parameter, delta, is composed ofthree different components, or, partial solubility parameters relating to the specific intermolecular interactions:

in which delta-D, delta-P and delta-H are the dispersion, polarity, and Hydrogen bonding components, respectively. Hoy proposed a system to estimate total and partial solubility parameters. The unit used for those parameters is MPa^1/2. A detailed explanation of that parameter and its components can be found in "CRC Handbook of Solubility Parameters and Other Cohesion Parameters", second edition, pages 122-138. That and other references provide tables with the parameters for many compounds. In addition, methods for calculating those parameters are provided.

In some exemplary embodiments of the invention, SI has a boiling point at latm between 100°C and 200°C and forms a heterogeneous azeotrope with water having a boiling point at latm of less than 100 °C.

Additional exemplary compositions are characterized in terms of their phases and/or relationships of various components within those phases. These compositions are characteristic of methods according to various embodiments of the invention.

Another aspect of some embodiments of the invention relates to separating HCl from lignin. In some exemplary embodiments of the invention, the lignin is provided in a liquid suspension including water and/or SI. This aspect presents at least two technical problems. One technical problem is that lignin absorbs a lot of water. A ton of lignin may absorb as much as 8 to 14 tons of water, optionally about 9 to 11 tons, optionally about 10 tons. In the context of acid hydrolysis, this water may contain 30 to 42 % HCl. According to some literature, lignin also absorbs HCl from the HCl solution surrounding it and/or absorbed in it. This residual HCl presents a second technical problem because it renders the lignin unsuitable for use as a fuel. Unsuitability stems from the fact that combustion would release HCl fumes into the air and/or corrode the furnace.

Another aspect of some embodiments of the invention relates to recovering HCl from lignin in a form which can be re-cycled to an acid hydrolysis reaction. According to various exemplary embodiments of the invention HCl is recovered as gas and/or liquid (i.e. in an aqueous solution). Accomplishing this recovery without diluting the HCl in water to an unacceptable degree presents an additional technical problem. Dilution presents a major problem since HCl forms an azeotrope with water at about 20%, so that re-concentration to >42% is economically unattractive. In some exemplary embodiments of the invention, the recovered HCl is not diluted at all.

Another aspect of some embodiments of the invention relates to recovering and/or recycling SI from a mixture of SI and HCl and/or water. Accomplishing this recovery without significant solvent loss and/or degradation presents an additional technical problem.

The phrase "adapted to" as used in this specification and the accompanying claims imposes additional structural limitations on a previously recited component.

Various exemplary embodiments of the invention relate to use of different solvents, under different conditions and over a wide range of industrial scales. One of ordinary skill in the art will be able to implement any relevant adaptations, by considering the specific solvents(s) and any relevant temperature and/or pressure conditions, using this specification as a guide.

The terms "extracting" and "extraction" and grammatical variations thereof as used in this specification and the accompanying claims indicate contacting between a liquid extractant and another liquid containing material. The result of such an extraction is transfer of one or more materials to the liquid extractant in a selective manner. By way of example, SI is employed in some exemplary embodiments of the invention to extract HCl and/or water from a lignin containing stream and/or from carbohydrates containing streams. According to such exemplary embodiments, HCl is extracted to both carbohydrates and water.

The terms "soluble in" and "solubility" and grammatical variations thereof as used in this specification and the accompanying claims indicate solubility of a first substance in a second substance at 25 degrees centigrade.

Throughout this specification and accompanying claims the term unless otherwise specified, "soluble carbohydrates" indicates solubility in water and/or aqueous HCl solutions and "insoluble carbohydrates" means insoluble in water and/or aqueous HCl solutions unless otherwise specified.

In some exemplary embodiments of the invention, a hydrolyzate stream or lignin stream is described as being extracted. According to various exemplary embodiments of the invention this extraction may be on the stream per se or on a modified stream. Optional modifications include, but are not limited to, dilution, concentration, mixing with another stream, temperature adjustment, and filtration. Optionally, two or more modifications may be performed prior to extraction.

In some exemplary embodiments of the invention, HCl selectively transfers to the extractant during extraction to form an HCl-carrying extract and an HCl-depleted stream. Optionally, HCl is recovered from the extract. In some exemplary embodiments of the invention, recovered HCl is recycled.

In some exemplary embodiments of the invention, there is provided a lignin composition including:

(a) lignin; (b) water; (c) a first organic solvent (SI) characterized by a water solubility of less than 15% and characterized by at least one of: (i) a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa^{1 2} ; and (ii) a hydrogen-bond related component of Hoy's cohesion parameter (delta-H) between 5 and 20 MPa^{1 2}.

Optionally, the composition includes HCl.

Optionally, the composition includes at least one carbohydrate.

Optionally, the lignin is solid.

Optionally, SI is selected from the group consisting of alcohols, ketones and aldehydes having at least 5 carbon atoms. Optionally, SI is selected from the group consisting of hexanol, 2-ethyl-hexanol and combinations thereof.

Optionally, SI has a boiling point at 1 atm of between 100°C and 200°C; and

SI forms a heterogeneous azeotrope with water and the azeotrope has a boiling point at 1 atm of less than 100 °C.

Optionally, the carbohydrate includes one or more members selected from the group consisting of glucose, mannose, xylose, galactose, arabinose and oligosaccharides thereof with a chain length less than 11 sugar units.

Optionally, the composition includes between 5% wt and 50% wt lignin, less than 12% wt water, between 50% wt and 90% wt of SI and less than 10% wt HC1.

Optionally, the composition includes more than 0.05% HC1.

Optionally, the composition has a carbohydrate content of less than 5%wt.

Optionally, the weight ratio of SI to water in the composition is Rl, and SI forms a heterogeneous azeotrope with water, and the weight ratio of SI to water in the azeotrope is R12 and Rl is greater than R12 by at least 10%, optionally 20%, optionally 30% and optionally 50%.

Optionally, the composition is characterized by at least one of :

a solid lignin content between 3 wt% and 40 wt%, optionally between 5%wt and 30%wt and optionally between 6%wt and 25%wt;

a weight ratio of HC1 to water greater than 0.3, optionally 0.4, optionally 0.5, optionally 0.6; a weight ratio of HC1 to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25; a weight ratio of water to SI greater than 0.15, optionally 0.2, optionally 0.25, optionally 0.3, optionally 0.35; and

a weight ratio of carbohydrate to lignin less than 0.05.

Optionally, the composition includes a single liquid phase.

Optionally, the weight ratio of HC1 to water is greater than 0.3, optionally 0.4, optionally 0.5, optionally 0.6; the weight ratio of HC1 to SI is greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25; and the weight ratio of water to SI is greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25.

Optionally, the composition is of multiple phases.

Optionally, the composition includes a solid lignin.

Optionally, the majority of the lignin in the composition, optionally essentially all of it, is solid. a concentrated HCl aqueous phase with a weight ratio of HCl to water greater than 0.4, optionally 0. 5, optionally 0.6; and

a phase including SI, water and HCl, with:

a weight ratio of HCl to water greater than 0.3, optionally 0.4, optionally 0.5, optionally 0.6; a weight ratio of HCl to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25, and a weight ratio of water to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25.

In some exemplary embodiments of the invention, there is provided an acid recovery method including: (a) providing a lignin stream including lignin, HCl and water, the weight ratio of lignin to water is in the range of 0.05 to 2 and the weight ratio of HCl to water is in the range of 0.15 to 2;(b) contacting the lignin stream with SI to form a lignin composition as set forth in table 1; and (c) forming de-acidified lignin.

Optionally, the forming de-acidified lignin includes separating SI from lignin.

Optionally, the separating SI from lignin includes at least one of decantation, filtration, centrifugation, distillation, extraction with another solvent and distillation of SI and water azeo trope.

Optionally, a weight ratio of HCl to lignin in the de-acidified lignin is less than 0.03, optionally less than 0.02, optionally less than 0.01 and optionally less than 0.005.

Optionally, providing the lignin stream includes hydrolyzing a lignocellulosic material in an HCl- including hydrolysis medium.

Optionally, HCl concentration in the medium is greater than azeotropic, optionally greater than 30%wt, optionally greater than 35%wt, and optionally greater than 40%wt.

In some exemplary embodiments of the invention, there is provided a hydrolysis method including: (a) providing a lignocellulosic material feed including a polysaccharide and lignin; (b) hydrolyzing the polysaccharide with HCl to form: a hydrolyzate including at least onecarbohydrate and HCl; and a lignin stream including lignin, HCl and water, (c) de- acidifying the hydrolyzate by extraction with a first extractant including SI, to form:

an HCl-carrying first extract; and an HCl-depleted carbohydrate solution; (d) recovering HCl from the first extract and (e) de-acidifying the lignin stream as described above.

Optionally, the polysaccharide includes at least one of cellulose and hemicellulose.

Optionally, the method includes using a separated concentrated aqueous HCl stream in the hydrolysis. Optionally, a lignin:water weight ratio in the lignin stream is in the range of 0.05 to 2.0, optionally 0.06 to 1.5 and optionally 0.07 to 1.0.

Optionally the weight/weight ratio of HCl:water in the lignin stream is in the range of 0.15 to 1, optionally 0.20 to 0.9 and optionally 0.25 to 0.8.

Optionally, a carbohydrates:water weight ratio in the hydrolyzate is in the range of 0.2 to 2, optionally 0.3 to 1.5 and optionally 0.4 to 1 and a weight ratio of HClrwater in the hydrolyzate is in the range of 0.17 to 0.60, optionally 0.2 to 0.55 and optionally 0.25 to 0.50.

Optionally, the method includes extracting the HCl-depleted carbohydrate solution with a second extractant including SI and a second solvent S2 characterized by a water solubility of at least 30% and by at least one of : (i) having a delta-P greater than 8 MPa^{1 2}; and (ii) having a delta-H greater than 12 MPa^{1 2}; to form a deacidified carbohydrate solution.

Optionally, S2 is selected from the group consisting of C1-C4 mono- or poly-alcohols, aldehydes and ketones and combinations thereof.

Optionally, an HClxarbohydrate weight ratio in the HCI-depleted carbohydrate solution is less than 0.03, optionally less than 0.01 and optionally less than 0.005.

Optionally, the lignin stream includes an impurity, and a ratio of impurity. ignin (W/W) in the lignin stream relative to a same weight ratio in the de-acidified lignin is greater than 1.5.

Optionally, the lignin composition serves as a first evaporation feed, and the method includes: evaporating water, HCl and SI from the first evaporation feed to produce a first vapor phase and a lignin containing phase.

Optionally, the method includes: contacting the lignin stream, with SI to form a first evaporation feed, and evaporating water, HCl and SI from the first evaporation feed to produce a first vapor phase and a lignin composition as described above.

Optionally, the evaporation is conducted at a temperature below 100°C and at a pressure below latm.

In some exemplary embodiments of the invention, SI forms a heterogeneous azeotrope with water; and a weight ratio of Sl:water in the first evaporation feed is R13, and a weight ratio of Sl:water in the azeotrope is R12 and R13 is greater than R12 by at least 10%.

Optionally, the lignin stream includes solid lignin, and at least one carbohydrate; a content of solid lignin is 5% wt to 30% wt; a weight ratio of HCl to water is greater than 0.5; and a weight ratio of carbohydrate to lignin is less than 0.05; the contacting is with an SI- including stream and forms a lignin composition 11 or 12 set forth in table 1, and the method includes separating the solid lignin to form a separated solid lignin and a separated liquid stream includes SI, HCl and water with a weight ratio of HCl to water greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; a weight ratio of HCl to SI greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25; and a weight ratio of water to SI is greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3; optionally 0.35.

Optionally, the separated liquid stream includes a single liquid phase.

Optionally, the method includes distilling gaseous HCl from the separated liquid stream to form gaseous HCl and an HCl-depleted liquid stream.

Optionally, providing the lignin stream includes hydrolyzing a lignocellulosic material in an HCl- containing hydrolysis medium and gaseous HCl is used to form the hydrolysis medium.

Optionally, the HCl-depleted liquid stream splits at 25°C into an HCl-depleted heavy phase, which heavy phase includes HCl, water and SI, and into an HCl-depleted light phase, which light phase includes HCl, water and SI, and the HCl-depleted heavy phase is separated from the HCl-depleted light phase.

In some exemplary embodiments of the invention, there is provided a hydrolysis method including: (a) providing a lignocellulosic material feed including a polysaccharide and lignin, the lignin including solid lignin; (b) hydrolyzing the polysaccharide with HCl to form a hydrolyzate including at least one carbohydrate and HCl; and a lignin stream including lignin, HCl and water, (c) de-acidifying the hydrolyzate by extraction with a first extractant including SI, to form: an HCl-carrying first extract; and an HCl-depleted carbohydrate solution; (d) recovering HCl from the first extract; and (e) de-acidifying the lignin stream as described above.

Optionally, the lignin stream includes carbohydrates and the method includes contacting the lignin stream with an aqueous acid stream and separating to form a separated carbohydrate-depleted lignin stream and a separated carbohydrate- including acid stream.

Optionally, the lignin stream includes solid lignin and a solid lignin content is in the range of 5 wt to 30 wt; an HCl:water weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and a carbohydrate:lignin weight ratio is less than 0.05; the contacting is with a recycled stream including SI, water and HCl where an HCl:water weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6;an HC1:S1 weight ratio is greater than 0.2; and a watenSl weight ratio is greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25;the contacting forms a multi-phase composition including: solid lignin; a concentrated aqueous HC1 with an HC water weight ratio greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and a phase including SI, water and HC1 with an HCl:water weight ratio greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6, an HCl.Sl weight ratio is greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25; and a watenSl weight ratio is greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3, optionally 0.35; the method includes: separating the multi-phase composition into at least 3 streams: (a) a separated lignin composition as set forth in lines 15 or 16 of table 1; (b) a separated concentrated aqueous HC1 stream with an HChwater weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and (c) a separated stream includes SI, water and HC1 with an HCl:water weight ratio greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; an HC1:S1 weight ratio greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25; and

a watenSl weight ratio greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3, optionally 0.35; and the method includes reusing the separated stream includes SI, water and HC1 from the separating as the recycled stream includes SI, water and HC1.

Optionally, an HCl:water ratio in the separated stream including SI, water and HC1 is greater than a same ratio in the separated concentrated aqueous HC1 stream.

In some exemplary embodiments of the invention, there is provided a hydrolysis method including: (a) providing a lignocellulosic material feed including a polysaccharide and lignin; (b) hydrolyzing the polysaccharide with HC1 to form a hydrolyzate including at least one carbohydrate and HC1; and a lignin stream includes lignin, HC1 and water, (c) de- acidifying the hydrolyzate by extraction with a first extractant including SI, to form: an HC1- carrying first extract; and an HCl-depleted carbohydrate solution; (d) recovering HC1 from the first extract(e) de-acidifying the lignin stream as described above.

Optionally, the weight ratio of lignin to water in the lignin stream is in the range of 0.02 to 0.25, optionally 0.1 to 0.15; and the weight ratio of HC1 to water is in the range between 0.15 and 0.32 and the method includes producing a lignin enriched stream by mechanically treating the lignin stream to increase the weight ratio of lignin to water to at least 0.30, optionally at least 0.35.

Optionally, the method includes washing the lignin stream to remove soluble carbohydrates. Optionally, the washing employs a stream of 20% to 40%, optionally, 25% to 35%, optionally, 28 to 32 % HCl.

Optionally, the method includes combining the lignin enriched stream with SI; and distilling the SI to produce a de-acidified slurry of lignin containing residual SI.

Optionally, the method includes removing the residual SI from the slurry.

Optionally, the removing employs centrifugation.

Optionally, the removing includes addition of water and distillation of the residual SI as an azeotrope with water.

In some exemplary embodiments of the invention, there is provided a hydrolysis method including: (a) providing a lignocellulosic material feed includes a polysaccharide and lignin; (b) hydrolyzing the polysaccharide with HCl to form: a hydrolyzate including at least one carbohydrate and HCl; and a lignin stream includes lignin, HCl arid water, (c) de- acidifying the hydrolyzate by extraction with a first extractant includes SI, to form an HC1- carrying first extract; and an HCl-depleted carbohydrate solution; (d) recovering HCl from the first extract; and (e) de-acidifying the lignin stream as described above.

In some exemplary embodiments of the invention, there is provided a system including: (a) a hydrolysis vessel adapted to produce an acidic hydrolyzate containing an aqueous solution of HCl with dissolved sugars and a lignin stream including HCl and water; and (b) an explosion proof lignin stream processing module adapted to separate the lignin from the lignin stream.

Optionally, the system includes HCl recovery components adapted to recover the HCl from the lignin stream and deliver recovered HCl to the hydrolysis vessel.

Optionally, the HCl recovery components include an HCl gas generator and an absorber.

Optionally, the system includes a dryer adapted to dry the lignin separated from the stream.

Optionally, the lignin stream processing module includes lignin washing equipment adapted to lower at least one of a carbohydrate and an HCl concentration in the stream.

Optionally, the lignin stream processing module includes at least one distillation unit.

Optionally, at least one of the at least one distillation unit is a flash distillation unit.

Optionally, the lignin stream processing module is adapted to extract the lignin stream with an organic solvent. Optionally, the lignin stream processing module is adapted to heat a solvent and distill HC1 from the solvent.

Optionally, the system includes one or more lignin de-solventizing components.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although suitable methods and materials are described below, methods and materials similar or equivalent to those described herein can be used in the practice of the present invention. In case of conflict, the patent specification, including definitions, will control. All materials, methods, and examples are illustrative, as opposed to limiting.

As used herein, the terms "comprising" and "including" or grammatical variants thereof are to be taken as specifying inclusion of the stated features, integers, actions or components without precluding the addition of one or more additional features, integers, actions, components or groups thereof. This term is broader than, and includes the terms "consisting of" and "consisting essentially of" as defined by the Manual of Patent Examination Procedure of the United States Patent and Trademark Office.

The phrase "consisting essentially of" or grammatical variants thereof when used herein are to be taken as specifying the stated features, integers, steps or components but do not preclude the addition of one or more additional features, integers, steps, components or groups thereof but only if the additional features, integers, steps, components or groups thereof do not materially alter the basic and novel characteristics of the claimed composition, device or method.

The term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of architecture and/or computer science.

Implementation of various methods and/or operation of various described systems optionally involves performing or completing selected tasks or steps manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of exemplary embodiments of methods, apparatus and systems several selected steps could be implemented by hardware or by software on any operating system of any firmware or a combination thereof. For example, as hardware, selected steps of the invention could be implemented as a chip or a circuit. As software, selected steps of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In any case, selected steps of the method and system of the invention could be described as being performed by a data processor, such as a computing platform for executing a plurality of instructions.

Percentages ( ) of lignin and carbohydrates (e.g. sugars) are W/W (weight per weight) unless otherwise indicated. Percentages (%) of chemicals typically supplied as liquids (e.g. water) are W/W (weight per weight) unless otherwise indicated. Similarly, ratios of various components are presented as W/W (weight per weight) unless otherwise indicated. Percentages of HC1 are expressed as HCl/[HCl+water] unless otherwise indicated.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying figures. In the figures, identical and similar structures, elements or parts thereof that appear in more than one figure are generally labeled with the same or similar references in the figures in which they appear. Dimensions of components and features shown in the figures are chosen primarily for convenience and clarity of presentation and are not necessarily to scale. Similarly, spatial relationships depicted in the figures are not necessarily reflective of actual spatial relationships. The attached figures are:

Fig. 1 is a schematic overview of an exemplary industrial context of some embodiments of the invention;

Fig. 2 is a schematic representation of one stage in lignin processing and/or HC1 recovery according to some exemplary embodiments of the invention;

Fig. 3 is a schematic representation of another stage in lignin processing and/or HC1 recovery according to some exemplary embodiments of the invention;

Fig. 4 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 5 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 6 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 7 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 8 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention; Fig. 9 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 10 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 11 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 12 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Fig. 13 is a simplified flow diagram illustrating a method according to an exemplary embodiment of the invention;

Figs. 14a, and 14b show water concentration in hexanol as a function of HC1 concentration in hexanol for a solution not contacted with lignin (diamonds) as well as for the wash solutions passed through the column (squares) based upon experimental examples 5 and 6 respectively; and was solutions prior to loading on the column (triangles) based upon experimental examples 5 and 6 respectively.

Figs. 15a and 15b show water concentration in hexanol as a function of HC1 concentration in hexanol for a solution not contacted with lignin (diamonds) as well as for the wash solutions passed through the column (squares) and was solutions prior to loading on the column (triangles) based upon experimental examples 5 and 6 respectively.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention relate to lignin compositions and/or methods of de- acidifying lignin and/or recovering acid and/or purifying carbohydrates (i.e. soluble sugars) from a lignocellulosic substrate.

Specifically, some embodiments of the invention can be used to recover acid from and/or eliminate water from residual lignin resulting from acid hydrolysis

The principles and operation of compositions, methods and systems according to exemplary embodiments of the invention may be better understood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

System Overview

Fig. 1 is a schematic overview of an exemplary industrial context of some embodiments of the invention depicting relevant portions of an acid hydrolysis system for processing of lignocellulosic material indicated generally as 100. Depicted system 100 includes an hydrolysis vessel 110 which takes in lignocellulosic substrate 112 and produces two exit streams. The first exit stream is an acidic hydrolyzate 130 containing an aqueous solution of HCl with dissolved sugars. The second exit stream 120 is a lignin stream. Processing of lignin stream 120 to remove HCl and water is one focus of this application. Recycling of the removed HCl is ah additional focus of this application. Ways to accomplish this recycling without diluting the HCl are an important feature of some exemplary embodiments described herein.

In some exemplary embodiments of the invention, hydrolysis vessel 110 is of the type described in co-pending US Provisional application 61/483,777 filed May 9, 2011 entitled "Hydrolysis Systems and Methods" which is fully incorporated herein by reference.

In other exemplary embodiments of the invention, hydrolysis vessel 110 is of the type described in co-pending US Provisional application 61/487,319 filed May 18, 2011 entitled "Hydrolysis Systems and Methods" which is fully incorporated herein by reference.

Alternatively or additionally, the hydrolysis vessel may include hydrolysis reactors of one or more other types.

System 100 indicates that processing of lignin stream 120 occurs in lignin processing module 200 and produces lignin 220 which is substantially free of residual HCl and/or water and/or soluble carbohydrates. As will be explained below, lignin processing module 200 optionally includes two or more sub-modules. For purposes of the overview of system 100, it is sufficient to note that module 200 produces a re-cycled stream 140 of concentrated HCl which is routed to hydrolysis vessel 110. In some exemplary embodiments of the invention, HCl gas 192 is added to stream 140 by means of an absorber 190. In some exemplary embodiments of the invention, the HCl gas is also produced by module 200.

In some exemplary embodiments of the invention, module 200 is provided as an explosion proof module. The phrase "explosion proof as used in this specification and the accompanying claims indicates that the module is designed and configured to separate lignin from the lignin stream while insulating electrical components, and sparks produced thereby, from potentially flammable vapors present in the module.

Exemplary Lignin Washing Equipment

Fig. 2 is a schematic representation of one sub-module in lignin processing module 200 according to some exemplary embodiments of the invention generally depicted as lignin washing module 201. According to an exemplary embodiment of the invention in which about 229,000 pounds/hour of wood is processed in reactor vessel 110, lignin stream 120 exits reactor vessel 110 at rate of about 530,000 pounds/hour. Roughly half of stream 120 is water. A little more than 191,000 pounds/hour is HC1 and about 56,000 pounds/hour is estimated to be lignin. This figure for estimated lignin appears to decrease during processing although it is not believed that any significant amount of lignin is lost. One possible reason for the apparent decrease is a change in the amount of HC1 and/or water absorbed in the lignin. Overall HC1 concentration in stream 120 can be as high as about 42%. Sugar concentration in stream 120 is in the range of about 5 to 7%, optionally about 6%.

In the depicted embodiment, washing module 201 includes a series of four physically similar processing towers depicted schematically as 210, 222, 224 and 226. Each of these towers is designed to receive stream 120 at its lower end and move it upwards to be passed out from its upper end to the lower end of the next tower in line. Upward transport of stream 120 within the towers can be achieved, for example, using a rotating auger. Exit streams of these four towers are indicated as 120a, 120b, 120c and 120d respectively.

Tower 210 is configured as a drainage tower. As stream 120 is conducted upwards, concentrated HC1 (dashed line) is allowed to drain out of the stream and is recycled to reactor vessel 110. This drainage is a mechanical treatments which decreases the total flow in pounds per hour of lignin stream 120a relative to 120 and increases the amount of lignin relative to liquid, but does not alter the ratio of HC water. In one exemplary embodiment of the invention, about 529,000 pounds per hour of lignin stream 120 enter tower 210 and about 464,000 pounds per hour of lignin stream 120a enter tower 222 with about 65,000 pounds per hour of liquid hydrolyzate returning to 110.

Towers 222, 224 and 226 are configured as a countercurrent wash system for the rightwards moving lignin stream. Although three such towers are depicted, various exemplary embodiments of the invention may employ a single tower or 4, 5 or more towers. In the depicted exemplary embodiment countercurrent washing is with a recovered or recycled solution of about 30% HCl (dashed line; from 320) which is introduced into the top of tower 226 where it flows to the bottom. This wash stream is then transferred to the top of tower 224 where it flows to the bottom and is transferred again to the top of tower 222 where it flows to the bottom and is removed.

This washing serves to lower the HCl concentration in 120d to about 30%. Alternatively or additionally, this washing serves to lower the soluble carbohydrate concentration in 120d to less than 3%, optionally less than about 1% optionally less than about 0.5%, optionally less than about 0.03%. In some exemplary embodiments of the invention, these carbohydrates washed from the lignin stream are routed back to hydrolysis reactor 110.

In addition, according to the exemplary feed rate given above, lignin stream 120d exiting tower 226 has a total flow rate of about 286,000 pounds/hour. Roughly 27% of stream 120d is water and about 34,000 pounds/hour is lignin. As the lignin stream moves through the series of four towers 210-226, the lignin concentration increases from 5 to 10%, optionally from about 7% (120) to about 12% (120d).

Aqueous HCl leaving the bottom of tower 222 has a concentration between 30 and 42% and is returned to reactor vessel 110. In the depicted embodiment, this return is via absorber 190 where HCl gas is added to increase the HCl concentration.

Conversely, as the wash stream moves to the left, it increases in size as it absorbs liquid and sugars from the lignin stream. According to the numerical example begun above, about 272,000 pounds per hour of liquid was stream enters tower 226 from 320 and about 652,000 pounds/hour of liquid is routed to absorber 190 from the bottom of tower 222. About 201,000 pounds per hour of this flow is from mechanical separation apparatus 250 described below.

Stream 120d is routed to a mechanical separation apparatus 250. Apparatus 250 may be, for example, a centrifuge or press. Optionally, apparatus 250 works on a continuous flow basis. Apparatus 250 extracts a stream of liquid HCl (dashed line) which is returned to hydrolysis vessel 110. Optionally, this return is via tower 222 and/or absorber 190.

In some exemplary embodiments of the invention, the relatively low concentration of HCl in 120d contributes to an amenability of the stream to a desired industrial process. For example, a 30% HCl concentration can be processed in a flow through centrifuge (optionally 250) while a 42% HCl stream is much more difficult to process in this manner. Increased vapor pressure of HCl at higher concentrations contributes to the degree of processing difficulty. Following removal of the bulk of the liquid, the lignin exits apparatus 250 as lignin stream 220e. Stream 220e (based on the example begun above) has a total flow rate of about 85,000 pounds/hour of which about 36,000 pounds is water, about 15,000 pounds is HCl and about 34,000 pounds is lignin. Although the HCl concentration has not changed relative to 120d, the total amount of liquid to be processed is significantly reduced. Sugar concentration is still about 0.5%.

In some exemplary embodiments of the invention, lignin stream 120 is provided at a temperature of 12 to 17, optionally about 15 degrees centigrade. In some exemplary embodiments of the invention, the wash solution applied to column 226 from 320 is delivered at a temperature of 30 to 70, optionally about 50 degrees centigrade. These exemplary conditions result in a heat exchange so that stream 120d is below 30 degrees centigrade, optionally below 28 degrees centigrade, optionally 26 to 27 degrees, optionally about 25 degrees centigrade. In some exemplary embodiments of the invention, increasing temperature of the lignin stream contributes to an increase in washing efficiency. Optionally, this increase in efficiency is related to a decrease in viscosity. In some exemplary embodiments of the invention, a decrease in viscosity of a liquid portion of stream 120 contributes to an increase in draining efficiency.

According to various exemplary embodiments of the invention, washing module 201 contributes to a reduction in the sugar concentration in stream 120 by decreasing HCl concentration and/or by decreasing viscosity and/or by increasing temperature.

Exemplary Lignin De-acidification Equipment

Fig. 3 is a schematic representation of another stage in lignin processing and/or HCl recovery according to some exemplary embodiments of the invention indicated generally as flash distillation module 300. Module 300 is a sub-module of module 200 as depicted in figure 1.

The main components of module 300 are a flash distillation tower 310 and a solvent distillation tower 320. Lignin stream 220e enters flash distillation tower 310 where it mixes with an excess of solvent [SI] (dotted line from distillation tower 320) and is flash distilled by steam 330a. In some exemplary embodiments of the invention, distillation tower 320 is a recycling mechanism used to recover solvent used to separate HCl from hydrolyzate 130 (figure 1). In the depicted exemplary embodiment, solvent distillation tower 320 provides HCl gas 192, which can optionally be routed to absorber 190 (figure 1) and a flow of aqueous HC1 at a concentration of about 30% which is optionally the source of wash solution entering wash tower 226.

S 1 , which forms a heterogeneous azeotrope with water, drives all the water and acid out the top of tower 310 leaving a de-acidified slurry 220f of lignin in SI. HC1 (dashed line) exits tower 310 as a gas and/or as a concentrated liquid 192 and is routed to absorber 190 (not seen in this figure) for recovery.

In some exemplary embodiments of the invention, the bottom of tower 310 has a temperature of about 150 degrees centigrade while the top has a temperature of about 100 degrees centigrade, which is at or above the azeotropic boiling point for the solvent and water.

De-acidified lignin slurry 220f is subject to additional solvent removal 370. In some exemplary embodiments of the invention, solvent removal 370 includes one or more of centrifugation, pressing and cooling to produce de-solventized lignin 220g.

Optionally, solvent removal 370 includes centrifugation and/or a Barr-Rosin ring dryer (a modified flash dryer; GEA Barr-Rosin; St. Charles, Illinois, USA) with a nitrogen atmosphere, which evaporates 90-95% of the solvent. Removed solvent (dotted line) is recycled to distillation tower 320, optionally via a splitter (350) which diverts a portion of the solvent stream to an impurities removal module (not depicted).

De-solventized lignin 220g is subject to final processing in a dryer 380 powered by steam 330b which removes any residual solvent and yields de-acidified dried lignin 220. Residual solvent from dryer 380 is returned (as depicted) to flash distillation unit 310 or returned (not depicted) to distillation tower 320. Using the input amounts described above, lignin is recovered at a rate of about 34,000 pounds per hour and is more than 99% pure. Optionally, dryer 380 includes a Rosinaire™ Paddle Dryer (GEA Barr-Rosin; St. Charles, Illinois, USA).

Exemplary Lignin Compositions

According to various exemplary embodiments of the invention one or more lignin compositions are used to achieve desired goals in the context of lignin processing as described hereinabove and/or hereinbelow. . Some important components and/or characteristics of lignin compositions according to various exemplary embodiments of the invention are set forth in Table 1, below. Compositions 1 to 16 of table 1 correspond to claims 1 to 16. In some exemplary embodiments of the invention, the lignin composition includes, lignin, water and a first organic solvent (SI) less than 15% soluble in water . Optionally, SI has a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa^1/2 . Alternatively or additionally, SI has a hydrogen-bond related component of Hoy's cohesion parameter (delta-H) between 5 and 20 MPa^1/2. Such a composition optionally includes HCl and/or one or more carbohydrates. In many cases the lignin is at least partially solid lignin.

In some cases SI includes one or more alcohols, ketones or aldehydes having at least 5 carbon atoms. In some exemplary embodiments of the invention, SI includes hexanol, 2- ethyl-hexanol or combinations thereof.

In some exemplary embodiments of the invention, SI has a boiling point at latm between 100°C and 200°C. Optionally, SI forms a heterogeneous azeotrope with water and the azeotrope has a boiling point at latm of less than 100 °C.

In those cases where the composition includes carbohydrate, the carbohydrates may include one or more of glucose, mannose, xylose, galactose, arabinose and oligosaccharides thereof with a chain length of less than 11 sugar units.

Compositions of this general type are useful in various extraction protocols and/or distillation protocols according to exemplary embodiments of the invention.

A first sub-class of compositions provides various additional exemplary embodiments of the invention in which the composition includes 5 to 50% W:W lignin, less than 12% W:W water, between 50 and 90% W:W of SI and less than 10% W:W HCl. Alternatively or additionally, the composition includes more than 0.05% HCl.

Optionally, the carbohydrate content is less than 5% W:W.

Table 1; Summar of exem lar i nin com ositions accordin to various exem lar embodiments of the invention

Optionally, the weight ratio of SI to water is Rl, wherein SI forms a heterogeneous azeotrope with water, wherein the weight ratio of SI to water in the azeotrope is R12 and wherein Rl is greater than R12 by at least 10%.

Compositions of this sub-class are typically found during distillation associated with performance of a method according to an exemplary embodiment of the invention.

A second sub-class of compositions provides various additional exemplary embodiments of the invention in which the composition includes solid lignin content between 3 and 40 W:W. Optionally, a weight ratio of HCl to water is greater than 0.5 and/or a weight ratio of HCl to SI is greater than 0.2 and/or a weight ratio of water to SI is greater than 0.35 and/or a weight ratio of carbohydrate to lignin is less than 0.05. In some exemplary embodiments of the invention, a composition of this type includes a single liquid phase.

Compositions belonging to this sub- class are useful in extraction according to some exemplary embodiments of the invention.

A third sub-class of compositions provides various additional exemplary embodiments of the invention in which the ratio of HCl to water W:W is greater than 0.5 and/or the ratio of HCl to S 1 W: W is greater than 0.2 and/or the ratio of water to S 1 W: W is greater than 0.35.

This third sub-class also includes compositions including a solid lignin, a concentrated HCl aqueous phase with a ratio of HCl to water W:W greater than 0.5; and a phase comprising SI, water and HCl, with a ratio of HCl to water W:W greater than 0.5, a ratio of HCl to SI W:W greater than 0.2, and a ratio of water to SI W:W greater than 0.35.

This third sub-class is useful, for example, in which SI is used to displace HCl/water from a lignin stream.

Overview of Exemplary Methods

Lignin de-acidification methods according to various exemplary embodiments of the invention can be broadly divided into 4 categories as set forth in Table 2, below. All 4 categories are applied to a feed including lignin which is roughly 10% solids and 90% liquids. Of the liquids, the vast majority is HCl at the percentage indicated. All four categories employ a solvent removal process downstream of the acid removal process. Mechanical removal in category IV includes, but is not limited to centrifugation. In some exemplary embodiments of the invention, reducing a concentration of HCl in the lignin stream contributes to ease of centrifugation. Optionally, a concentration of about 30% HCl makes centrifugation on an industrial scale feasible.

Table 2:Categories of methods according to various exemplary embodiments of the invention

Each lignin de-acidification method can also be described as an HCl recovery method and/or as a carbohydrate recovery method belonging to an upstream acid hydrolysis process (see Fig. 1 and accompanying explanation). These additional methods and/or processes are additional embodiments of the invention.

General Description of Exemplary Acid recovery Methods:

Fig. 4 is a simplified flow diagram of an acid recovery method according to some exemplary embodiments of the invention indicated generally as 400. Although described as an acid recovery method, the depicted method could also be described as a lignin de- acidification and/or lignin purification method.

Depicted method 400 includes providing 410 a lignin stream comprising lignin, HCl and water. In some exemplary embodiments of the invention, the weight ratio of lignimwater is between 0.1 and 2 W:W and the weight ratio of HC water is between 0.15 and 2 W:W. In some exemplary embodiments of the invention, the lignin stream is provided by hydrolyzing a lignocellulosic material with HCl wherein HCl concentration in the hydrolysis solution is greater than azeotropic.

Method 400 includes contacting the lignin stream with a solvent (SI) to form a lignin composition according as set forth in table 1. (420) and forming de-acidified lignin (430).

Optionally, forming de-acidified lignin involves separating SI from lignin. According to various exemplary embodiments of the invention, separating SI from lignin may involve one or more of decantation, filtration, centrifugation, distillation, extraction with another solvent and distillation of S 1 and water azeotrope.

In some exemplary embodiments of the invention, a weight ratio of HCl to lignin in the de-acidified lignin is less than 0.03. Method 400 is relevant to types I-IV in table 2.

Exemplary carbohydrate recovery methods described in general terms;

Fig. 9 is a simplified flow diagram of a carbohydrate recovery method according to some exemplary embodiments of the invention indicated generally as 900: Although described as a carbohydrate recovery method, the depicted method could also be described as an acid recovery method and/or a lignin de-acidification and/or lignin purification method.

Depicted method 900 includes providing 910 a lignocellulosic material feed comprising a polysaccharide and lignin and hydrolyzing 920 the polysaccharide with HCl to form a hydrolyzate 922 comprising at least one carbohydrate and HCl and a lignin stream 924 comprising lignin, HCl and water. The depicted exemplary method 900 also includes de- acidifying 930 hydrolyzate 922 by extraction with a first extractant comprising a first solvent (SI). In some exemplary embodiments of the invention, HCl selectively transfers to SI. De- acidifying 930 produces an HCl-carrying first extract 932 and an HCl-depleted carbohydrate solution 934. Optionally, an HClrcarbohydrate weight ratio in 934 is less than 0.03.

Method 900 includes recovering 940 HCl from first extract 932 and de-acidifying 950 the lignin stream as indicated hereinabove. Optionally, HCl recovered at 940 is recycled for use in hydrolysis 920.

Optionally, a separated concentrated aqueous HCl stream is used in hydrolysis 920. Concentrated HCl may be, for example, 40-45% HCl, optionally about 42%.

In some exemplary embodiments of the invention, a lignimwater weight ratio in lignin stream 924 is in the range of 0.1 to 2.0 and/or a weight/weight ratio of HCl: water in lignin stream 924 is in the range of 0.15 to 1.

In some exemplary embodiments of the invention, a carbohydrates: water weight ratio in hydrolyzate 922 is in the range of 0.2 to 2 and/or a weight ratio of HCl:water in the hydrolyzate is in the range of 0.17 to 0.60.

Optionally, method 900 includes extracting 954 HCl-depleted carbohydrate solution 934 with a second extractant comprising SI and a second solvent (S2) characterized by a water solubility of at least 30% and/or a delta-P greater than 8 MPa and/or a delta-H greater than 12 MPa" . In some exemplary embodiments of the invention, HCl selectively transfers to the second extractant to form a de-acidified carbohydrate solution. In some exemplary embodiments of the invention, extraction 954 produces a deacidified carbohydrate solution with a lower concentration of HCl than HCl depleted carbohydrate solution 934. According to various exemplary embodiments of the invention S2 can include one or more of Cj-Q mono- or poly-alcohols, aldehydes and ketones.

In some exemplary embodiments of the invention, lignin stream 924 includes an impurity. A weight ratio of impurity to lignin in the lignin stream and in the deacidified lignin can be defined as R2 and R22, respectively. In some exemplary embodiments of the invention, the ratio of R2 to R22 is greater than 1.5.

Method 900 is relevant to types I-IV in table 2.

Exemplary acid recovery methods accordinfi to category I:

Fig. 5 is a simplified flow diagram of an acid recovery method according to some exemplary embodiments of the invention indicated generally as 500. Although described as an acid recovery method, the depicted method could also be described as a lignin de- acidification and/or lignin purification method.

Depicted method 500 includes using a lignin composition as set forth in table 1 as a first evaporation feed. Method 500 includes evaporating 520 water, HC1 and SI from the first evaporation feed. Optionally, evaporation is at a temperature below 100°C and/or at a pressure below latm. Evaporation produces a first vapor phase 530 and a lignin containing phase 540.

Method 500 is relevant to type I in table 2.

Exemplary carbohydrate recovery methods according to category I:

Fig. 10 is a simplified flow diagram of a carbohydrate recovery method according to some exemplary embodiments of the invention indicated generally as 1000. Method 1000 is a variation of method 900 of figure 9.

Depicted method 1000 involves contacting 1030 hydro lyzate 922 of method 900 with a first extractant including SI . Optionally, the SI employed has a water solubility of less than

10% . Optionally, SI is characterized by a delta-P between 5 and 10 MPa^1/2 and/or a delta-H

1/2

between 5 and 20 MPa . In some exemplary embodiments of the invention HC1 selectively transfers to the extractant at this stage. Contacting 1030 produces an HCl-carrying first extract 1032 and an HCl-depleted carbohydrate solution 1034. Optionally, extract 1032 is subject to HC1 recovery 940 and/or solution 1034 is extracted 950 with SI and S2.

Depicted method 1000 also includes contacting 1050 a lignin stream, (e.g. 924) with SI to form a first evaporation feed 1052. Evaporation feed 1052 is then evaporated (1054) to eliminate water, HC1 and SI. This evaporation produces a first vapor phase 1064 and a lignin composition as set forth in table 1. In some exemplary embodiments of the invention, the lignin composition is a multi-phase composition.

In some exemplary embodiments of the invention, evaporation 1054 is conducted at a temperature below 100°C and at a pressure below latm.

Optionally, SI forms a heterogeneous azeotrope with water. In some exemplary embodiments of the invention, a weight ratio of Sl :water in first evaporation feed 1052 is greater than a weight ratio of SI to water in the azeotrope by at least 10%. These conditions tend to favor azeotrope formation.

Method 1000 is relevant to type I in table 2.

Exemplary acid recovery methods according to category II:

Fig. 6 is a simplified flow diagram of an acid recovery method according to some exemplary embodiments of the invention indicated generally as 600. Although described as an acid recovery method, the depicted method could also be described as a lignin de- acidification and/or lignin purification method.

Depicted method 600 includes using a lignin stream 610 including solid lignin, HCl, water and one or more carbohydrates. Optionally, a content of solid lignin is 5%wt to 30%wt and/or a weight ratio of HCl to water is greater than 0.5 and/or a weight ratio of carbohydrate to lignin is less than 0.05.

According to method 600, contacting 620 is with an SI -comprising stream and forms a lignin composition 11 or 12 as set forth in table 1.

In depicted exemplary method 600, the solid lignin is separated 622 to form a separated solid lignin 624 and a separated liquid stream 626 comprising SI, HCl and water. Optionally, liquid stream 626 is characterized by one or more of a weight ratio of HCl to water greater than 0.5, a weight ratio of HCl to SI greater than 0.2; and a weight ratio of water to SI greater than 0.35.

In some exemplary embodiments of the invention, separated liquid stream 626 comprises a single liquid phase. In some exemplary embodiments of the invention, stream 626 is distilled 630 to produce gaseous HCl 632 and HCl depleted liquid stream 634

Optionally, lignin stream 610 results from hydrolyzing a lignocellulosic material in an HCl-comprising hydrolysis medium and the gaseous HCl 632 is used to form the hydrolysis medium.

In some exemplary embodiments of the invention, the HCl-depleted liquid stream splits at 25°C into an HCl-depleted heavy phase 644 and an HCl-depleted light phase 642. Optionally, heavy phase 644 includes HC1, water and S 1 and/or light phase 642 includes HC1, water and SI. Optionally, an amount of HC1 in liquid stream 634 contributes to the composition of phases 642 and 644. In some exemplary embodiments of the invention, phases 642 and 644 are separated. Optionally, lignin tends to remain in the light phase. In some exemplary embodiments of the invention, light phase 642 is contacted with a lignin stream as a means of initial separation of lignin from HC1.

Method 600 is relevant to type II in table 2.

Exemplary carbohydrate recovery methods according to category II:

Fig. 11 is a simplified flow diagram of a carbohydrate recovery method according to some exemplary embodiments of the invention indicated generally as 1100. Method 1100 is a variation of method 900 of figure 9 and/or method 600 of figure 6.

Depicted method 1100 relates to cases where the lignin in lignin stream 1 124 includes solid lignin, HC1 and water and is subjected to de-acidification 1130 according to a method

600 of figure 6.

Optionally, lignin stream 1 124 includes carbohydrates. In some exemplary embodiments of the invention, method 1100 includes contacting 1140 the lignin stream with an aqueous acid stream and separating 1150 to form a separated carbohydrate-depleted lignin stream and a separated carbohydrate-comprising acid stream.

Practice of methods of this general type is compatible with type II of table 2.

Exemplary acid recovery methods according to category III:

Fig. 7 is a simplified flow diagram of an acid recovery method according to some exemplary embodiments of the invention indicated generally as 700. Although described as an acid recovery method, the depicted method could also be described as a lignin de- acidification and/or lignin purification method.

Depicted method 700 includes using a lignin stream 710 including solid lignin. In some exemplary embodiments of the invention, solid lignin content in stream 710 is between 5 and 30%wt. Alternatively or additionally, an HChwater weigh weight ratio is greater than 0.5 and/or a carbohydrate: lignin weigh weight ratio is less than 0.05. Method 700 is similar to method 400 and is characterized in that contacting 720 is with a recycled stream comprising SI, water and HC1 wherein. In some exemplary embodiments of the invention, this stream is characterized in that an HChwater weigh weight ratio is greater than 0.5 and an HChsolvent weigh weight ratio is greater than 0.2 and a watensolvent weigh weight ratio is greater than 0.35. In the depicted exemplary embodiment 700, contacting 720 forms a multi-phase composition 730 including solid lignin 732, a concentrated aqueous HCl 736 with an HChwater weigh weight ratio greater than 0.5 and a phase 734 comprising SI, water and HCl with an HCl:water weigh weight ratio greater than 0.5, an HChsolvent weigh weight ratio greater than 0.2 and a waterrsolvent weight: weight ratio greater than 0.35.

Depicted method 700 includes separating 740 multi-phase composition 730 into at least 3 streams. In the depicted embodiment, the streams are separated lignin composition 742 as listed in lines 15 or 16 of table 1, a separated concentrated aqueous HCl stream 746, and a separated stream 744 comprising SI, water and HCl. Optionally, stream 746 has an HC water weight:weight ratio greater than 0.5. Optionally, stream 744 has an HC water weigh weight ratio greater than 0.5, an HCl:solvent weigh weight ratio greater than 0.2 and a water:solvent weigh weight ratio greater than 0.35. In some exemplary embodiments of the invention stream 744 is used as a re-cycled stream 750 (to 720).

In some exemplary embodiments of the invention, an HCl:water ratio in stream 744 is greater than a same ratio in stream 746.

Method 700 is relevant to type III in table 2

Exemplary carbohydrate recovery methods according to category III:

Fig. 12 is a simplified flow diagram of a carbohydrate recovery method according to some exemplary embodiments of the invention indicated generally as 1200. Method 1200 is a variation of method 900 of figure 9 and/or method 600 of figure 6.

The depicted method could also be referred to as a lignin purification method and/or an HCl recovery method.

Depicted method 1200 includes providing 1210 a lignocellulosic material feed comprising a polysaccharide and lignin and hydrolyzing 1220 the polysaccharide with HCl. Hydrolysis 1220 produces a hydrolyzate 1222 comprising at least one carbohydrate and HCl and a lignin stream 1224 comprising lignin, HCl and water.

According to the depicted exemplary embodiment, hydrolyzate 1222 is de-acidified 1230 by extraction with a first extractant comprising SI . Optionally, hydrolyzate 1222 may be modified prior to this extraction. According to various exemplary embodiments of the invention the modification may include one or more of dilution, concentration, mixing with another stream, temperature adjustment, and filtration.

De-acidification 1230 produces an HCl-carrying first extract 1232 and an HC1- depleted carbohydrate solution 1234. Optionally, HCl is recovered 1240 from extract 1232. Alternatively or additionally, solution 1234 is extracted 1254 with an extractant including SI and S2 (see description of Fig. 9) to yield a de-acidified carbohydrate solution.

In the depicted exemplary embodiment, lignin stream 1224 is de-acidified 1250.

Optionally, de-acidification 1250 is according to a method as depicted in figure 7.

In some exemplary embodiments of the invention, HCl selectively transfers to the extractant to form an HCl-carrying first extract 1232 and an HCl-depleted carbohydrate solution 1230. In some exemplary embodiments of the invention, HCl is recovered 1240 from the first extract.

Method 1200 is optionally carried out in conjunction with a de-acidification method as depicted in figure 7.

Method 1200 is relevant to type III in table 2.

Exemplary acid recovery methods according to category 4:

Fig. 8 is a simplified flow diagram of an acid recovery method according to some exemplary embodiments of the invention indicated generally as 800. Although described as an acid recovery method, the depicted method could also be described as a lignin de- acidification and/or lignin purification method.

According to depicted exemplary method 800 a weight ratio of lignin to water in lignin stream 810 is in the range of 0.1 to 0.15; and a weight ratio of HCl to water is in the range between 0.15 and 0.32. Method 800 includes mechanical treatment of lignin stream 810 to increase the weight ratio of lignin to water to at least 0.35. According to various exemplary embodiments of the invention the mechanical treatment can include centrifugation and/or pressing and/or drainage. Optionally, a flow through centrifuge is employed.

Optionally, method 800 also includes washing 830 the treated lignin stream to remove soluble carbohydrates. Optionally, washing 830 employs a stream of 28 to 32 % HCl. Optionally this stream is about 30% HCl. Optionally, washing 830 includes application of a counter current stream. In some exemplary embodiments of the invention, washing 830 is conducted prior to and/or concurrently with mechanical treatment 820.

In some exemplary embodiments of the invention, mechanical treatment 820 produces a lignin enriched stream 812. Optionally, method 800 includes combining stream 812 with SI and distilling 840 a significant portion of the S I to produce a de-acidified slurry 814 of lignin containing residual SI .

In some exemplary embodiments of the invention, residual SI is removed 850. Optionally, the removing 850 employs centrifugation 852. Alternatively or additionally, removing 850 includes addition of water and distillation of the residual SI as an azeotrope with water. This distillation yield lignin 816 substantially free of SI and a mixture 818 of SI and water. Mixture 818 can be recycled. Optionally, recycling involves additional distillation via towers 310 and/or 320 (see figure 3).

Method 800 is relevant to type IV in table 2.

Exemplary acid hydrolysis method according to category 4:

Fig. 13 is a simplified flow diagram of an acid hydrolysis method according to some exemplary embodiments of the invention indicated generally as 1300. Although described as an acid hydrolysis method, the depicted method could also be described as a lignin production and/or lignin purification method and/or an acid recycling method.

Depicted exemplary method 1300 includes providing 1310 a lignocellulosic material feed comprising a polysaccharide and lignin and hydro lyzing 1320 the polysaccharide with HCl to form a hydrolyzate 1330 including at least one carbohydrate and HCl. The soluble carbohydrates in 1330 can be viewed as a primary product of method 1300. These carbohydrates may serve as an input for downstream fermentation reactions. Optionally, these ^Λ fermentation reactions produce ethanol or other bio-fuels.

Hydrolyzing 1320 also produces a lignin stream 1340 comprising lignin, HCl and water.

Method 1300 includes de-acidifying 1350 hydrolyzate 1330 by extraction with a first extractant comprising SI. In some exemplary embodiments of the invention, HCl selectively transfers to the first extractant. De-acidificatiortl350 produces an HCl-carrying first extract 1360 and an HCl-depleted carbohydrate solution 1370. In some exemplary embodiments of the invention, hydrolyzate 1330 is de-acidified 1350 directly. In other exemplary embodiments of the invention, hydrolyzate 1330 is de-acidified 1350 after modification. Exemplary modifications include filtration and/or dilution and/or concentration (e.g. by evaporation).

Method 1300 also includes recovering 1380 HCl from first extract 1360. In some exemplary embodiments of the invention, method 1300 includes de-acidifying 1390 lignin stream 1340. In some exemplary embodiments of the invention, de-acidification is according to a method as depicted in Fig. 8.

In some exemplary embodiments of the invention, lignin stream 1340 is mixed with an SI containing stream. Optionally, the SI containing stream is a recycled stream. In some exemplary embodiments of the invention, this mixing contributes to de-acidification 1390. Alternatively or additionally, this mixing contributes to ease of transfer of lignin stream 1340 to a desired location.

Exemplary flow control considerations:

In some exemplary embodiments of the invention flow control mechanisms are used to transport solids, slurries or liquids. Exemplary flow control mechanisms include, but are not limited to pumps and mechanical transport mechanisms. Because they are not central to the primary objectives of the described exemplary embodiments, these flow control mechanisms are not depicted in the drawings.

Optionally, pumps are used to transport liquids or slurries. For example, lignin stream 120 (figure 1) may be transported by a pump to lignin processing module 200. Alternatively or additionally, hydrolyzate stream 130 may pumped to further processing and/or storage (not depicted). Alternatively or additionally, HC1 stream 140 may be pumped before and/or after it passes through absorber 190.

Alternatively or additionally, mechanical transport mechanisms (e.g. conveyor belts or augers) are optionally used to transport solids or slurries containing a high solids concentration. For example, lignocellulosic substrate 112 may be transported by a conveyor belt to hydrolysis vessel 110. In some exemplary embodiments of the invention, lignocellulosic substrate 112 is provided as a slurry with aqueous HC1. Depending upon the solids content of the slurry, it may optionally be pumped. Alternatively or additionally, lignin streams 120a, 120b and 120c (figure 2) are handled by vertical augurs as they move through towers 222, 224 and 226 respectively. Alternatively or additionally, centrifuge 250 can be viewed as mechanical transport mechanism. In some exemplary embodiments of the invention, lignin stream 220e is transported to flash distillation unit 310 (figure 3) by a mechanical transport mechanism.

Exemplary energy balance considerations

In some exemplary embodiments of the invention, lignin 220 can be burned as an energy source. Optionally, energy from lignin combustion fuels various distillation processes (e.g. 310 and/or 320) and/or provides steam (e.g. 330a or 330b) and/or provides electric power to drive mechanical equipment (e.g. motors to turn augers in towers 210; 222; 224 and 226 and/or a motor of centrifuge 250 and/or various pumps or conveyors (not depicted) which facilitate material flows).

Exemplary cost considerations In some exemplary embodiments of the invention, production of re-cycled stream 140 of concentrated HC1 by module 200 and routing of that stream to hydrolysis vessel 110 contributes to a reduction in cost of the hydrolysis reaction being conducted in 110.

Alternatively or additionally, lignin 220 can be burned as an energy source to fuel various distillation processes (e.g. 310 and/or 320) and/or provide steam (e.g. 330a or 330b) and/or provide electric power to drive mechanical equipment (e.g. motors to turn augers in towers 210; 222; 224 and 226 and/or a motor of centrifuge 250 and/or various pumps or conveyors (not depicted) which facilitate material flows).

Optionally, energy from combustion of lignin 220 can be used on-site for purposes not directly related to the industrial processes described hereinabove. For example, electricity generated by lignin combustion can be used for climate control, lighting, operation of office equipment or to charge electric vehicles used in the plant.

Alternatively or additionally, electricity generated by lignin combustion can be sold to a power company to generate a revenue stream which contributes to a reduction in overall production costs of hydrolyzate 130 .

Exemplary materials

According to various exemplary embodiments of the invention, different parts of the depicted/described machinery may need to be resistant to HC1 at concentrations ranging from about 30% to about 42%. It is noted that use of acid concentrations at the lower end of this . ranges offers greater flexibility in selection of materials . Optionally, resistance can be achieved by construction from resistant materials and/or shielding from contact with the acid.

Resistant materials include but are not limited to Stainless steel, glass, and acid resistant plastics. Acid resistant plastics include, but are not limited to polyethylene and polypropylene, FEP (Hexafluoropropylene-tetrafluoroethylene Copolymer), PVDF (Polyvinylidene Difluoride), ECTFE (Ethylene chlorotrifluoroethylene), PCTFE (Polychlorotrifluoroethylene) and PEEK (PolyEtherEtherKetbne).

At relatively low HC1 concentrations, such as 30%, polypropylene may be acceptable.

Optionally, layers of plastic coating can be used to impart HC1 resistance to other materials that would otherwise be unsuitable for use in a corrosive acid environment.

It is expected that during the life of this patent many flow handling apparatus will be developed and the scope of the invention is intended to include all such new technologies a priori.

As used herein the term "about" refers to ? ^" 10 %. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Specifically, a variety of numerical indicators have been utilized. It should be understood that these numerical indicators could vary even further based upon a variety of engineering principles, materials, intended use and designs incorporated into the invention. Additionally, components and/or actions ascribed to exemplary embodiments of the invention and depicted as a single unit may be divided into subunits. Conversely, components and/or actions ascribed to exemplary embodiments of the invention and depicted as sub- units/individual actions may be combined into a single unit/action with the described/depicted function.

Alternatively, or additionally, features used to describe a method can be used to characterize an apparatus and features used to describe an apparatus can be used to characterize a method.

It should be further understood that the individual features described hereinabove can be combined in all possible combinations and sub-combinations to produce additional embodiments of the invention. The examples given above are exemplary in nature and are not intended to limit the scope of the invention which is defined solely by the following claims. Specifically, the invention has been described in the context of acid hydrolysis of wood but might also be used on other lignocellulosic substrates.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

The terms "include", and "have" and their conjugates as used herein mean "including but not necessarily limited to".

Additional objects, advantages, and novel features of various embodiments of the invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting. Additionally, each of the various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below finds experimental support in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with the above descriptions, illustrate the invention in a non limiting fashion.

EXAMPLE 1 :

Recovery of Hcl using azeotropic distillation

In order to examine the possibility of separating HCl from lignin using an organic solvent during distillation, a lignin composition according to an exemplary embodiment of the invention was prepared by mixing 18.77gr lignin, 18.14gr HCl and 60.28gr of water. This material approximates stream 120 in figure 1.

This simulated lignin stream was combined in a flask with 243.2 gr of fresh hexanol. Distillation at atmospheric pressure at about 102-103°C for 3 hours was conducted. Cooling of the distillate produced an organic solvent-rich phase (light phase) and an aqueous phase (heavy phase). A lignin cake remained in the feed flask in a brown liquid, rich in solvent.

The cake was filtered and analyzed. The dry solids (DS) of the cake was about 38%, the hexanol content was about 60%, and the HCl content, on as is basis, was about 0.7%.

This example illustrates that it is possible to effectively separate HCl from lignin using an organic solvent such as hexanol. This meyhod suggests that it is possible to overcome problems associated with HCl water azeotropes using an organic solvent, such as hexanol.

EXAMPLE 2:

Additional Azeotropic Distillation Experiment:

An azeotropic distillation was conducted as follows:

150g of wet lignin including 9g HCl and 23.6g water, was mixed with 375g hexanol and 37.5g water. Distillation was applied at atmospheric pressure at about 104°C. When the vapor temp reduced to ~50°C, vacuum was applied for 5 minutes and the distillation was ended.

Cooling of the distillate produced an organic solvent-rich light phase (light) and an aqueous phase (heavy). Within the feed flask remained a lignin cake which was filtered, dried over night at 150°C and analyzed for HCl concentrations (by titration). Results presented in Table 3 illustrate that the azeotropic distillation reduces the HCl contents within the lignin to less than 1%, over dry lignin. Table 3: Titration results

, This example confirms the results of Example 1.

EXAMPLE 3:

Hcl and Water Rejection From Lignin by Adding

Synthetic Solution of Hexanol-HCl-H₂Q

The ability of an organic solvent to separate lignin from aqueous HCl was demonstrated as follows:

14gr of acidified lignin was used. An analysis showed that the concentration of HCl was 38% and the total DS was 14%. The lignin was introduced into a vial with 30gr HCl 37%. HCl gas was bubbled in at a temperature of about 0-2°C. After bubbling was stopped, a sample of the solution was analyzed for HCl and water. This brings the HCl concentration to about 42%. This material is representative of unwashed lignin stream 120 in figure 1. The following experiment was conducted in order to examine the possibility of using hexanol to wash the residual HCl from the lignin without distillation.

The solution with the lignin was then transferred into an ice-cooled column with a valve on its bottom. Liquid was drained from the column and analyzed to confirm the HCl concentration.

The remaining 15g lignin cake was used in the experiment. The composition of that cake, as shown in Table 4, was determined from the analysis of the separated liquid and from the known amount of solid lignin.

Table 4: Initial lignin cake and hexanol-HCl-water compositions

* solvent phase The solvent phase was prepared by mixing the highly concentrated aqueous HCl solution, drained from the ice cooled column describe above was mixed with dry hexanol in an amount similar to that of the lignin cake to form a hexanol-HCl-water solution (see Table 4 for composition).

The ratio between the phases was such that, on equilibrium, two phases existed.

The lignin cake and the Hexanol-HCl-water solution were contacted in a column and gently mixed and transferred into a separatory funnel and allowed to settle, he composition separated into two phases:

a heavy phase that is essentially aqueous and includes some HCl; and

and a light phase containing hexanol water and HCl.

Surprisingly, the solid lignin was dispersed in the light phase.

The two phases were separated and analyzed. Results of the analysis are summarized in Table 5. Hexanol content of the heavy phase was not determined. The lignin phase was analyzed by washing with ethanol followed by analyzing the wash solution for water and HCl. The hexanol content was determined by difference. The analysis reported in Table 5 is for the upper region liquid as such. In addition, the DS of the lignin in the upper region was determined.

Table 5: Light and heavy phase compositions

Results summarized in table 5 indicate that 71% of the HCl, and 93% of the water originally present in the lignin cake were found in the heavy phase. HCl concentration in the heavy phase is relatively low. Possibly, part of the HCl was lost into the atmosphere during the operations (the total amount of HCl in the final phases is ~95% of the initial). Yet, about 16% of the initial HCl in the lignin cake was transferred into the light phase, HCl concentration of which grew from 24% to 25.1%. These results suggest that loading of hexanol in the solvent phase was too low.

However, the results suggests that this procedure can serve as at least a partial substitute for distillation in an industrial context. EXAMPLE 4:

HCL AND WATER REJECTION FROM LIGNIN USING LIGHT PHASE FROM

EXAMPLE 3

Lignin cake was prepared using 13 grams of lignin composition according to the method of Example 3 (analysis in Table 6).

A solvent phase was prepared by separating 32.8gr of light phase from the upper phase of Example 3 (See analysis in Table 6).

The lignin cake was contacted with the solvent phase (light phase). Observations, separation and analysis were done as in Example 3. The results are reported in Table 5.

Table 6: Initial lignin cake and hexanol-HCl-water compositions

Table 7: Li ht and heav hase composition

These results indicate that 81% of the HCl and 94% of the water originally present in the lignin cake were found in the heavy phase. For HCl, this is a significant increase relative to Example 3. HCl concentration in the heavy phase is still lower than the one in the lignin, but higher than that in Example 3 (38.8% and 36.8%, respectively). In the present example, HCl concentration in the light phase increases on contacting, as in the 1^st, but significantly less (from 25.1% to 25.4%).

These observations support the hypothesis that HCl concentration in the hexanol in the previous experiment was not high enough and suggest that at the correct initial HCl concentration of the light phase (which would be the case on recycling), practically all the HCl and water in the lignin cake will be rejected to the aqueous phase. EXAMPLE 5:

Recovery of HCl and Water from Lignin Using a Counter Current Solvent Wash

In order to evaluate the possibility of recovering HCl from Lignin using a counter current flow, a mock "lignin stream" (see 120 fig 1) with a composition as summarized in table 8 was washed and the composition of each wash was analyzed

Table 8: Lignin input

Briefly, 17.27gr lignin loaded into a column with a bottom stopcock. The diameter of the column was 2.5cm and the height was 15cm. After settling, the lignin reached a height of approximately 7.5 cm.

Five wash solutions were prepared as summarized in table 9. Each solution was loaded through the stopcock in the bottom end of the column, allowed to interact with the lignin in the column for about 20 minutes and drained through the stopcock into a separate container. The washes and drainings are indicated as stages 1 to 5 respectively in tables 9 and 10. Table 10 summarizes results for analyses of HCl and water (Washing solution No. 1 initially contained 2 phases but after mixing it was united to one phase, which was passed through the column again).

HCl and water amounts in the lignin phase (table 10) were calculated based upon the assumption that the lignin phase and the washing solution have the same composition of HCl water and hexanol.

Table 9: Initial composition of the washing solution of each stage

HCl H₂0 Hexanol HCl/100 solvent H₂O/100 solvent r Wt% Wt% Wt%

stage 1 30 11.3 11.8 77

stage 2 31 17.9 25.1 57 32.4 48.2

stage 3 30.6 12.8 21.8 65 19.7 33.5

stage 4 29.4 7.6 13.6 79 13.1 22.3

stage 5 7.88 0.0 0.0 100 Table No.10: com osition of column effluent and wet li nin in the column after each sta e

In order to facilitate analysis of liquid remaining on the lignin after the 5 hexanol washes, the lignin in the column was washed 3 times with ethanol. 55.8gr ethanol solution was recovered and analyzed for HCI and water. Results of this analysis are summarized in table 11.

Table 11: HCI and water amounts that remain with the lignin in the column after the 5 stage (analyzed by ethanol washing)

This example indicates that the series of 5 washes was sufficient to recover 81% of the HCI and 77% of the water initially present in the lignin loaded in the column. It is expected that HCI recovery would be higher if the loaded lignin contained 42% HCl/(HCl+water) instead of 38% HCI as in the current experiment.

In general, flow of the wash solution through the lignin was good and equilibrium was reached as indicated by the fact that in stage 5 the lignin phase composition calculated from the solvent is almost the same as the composition analyzed by the ethanol washing

The weight of lignin did not change appreciably after each wash.

These results suggest that a washing strategy consistent with table 9 can improve HCI recovery relative to the two previous examples. However, the method of this example requires use of dry hexanol, which implies a need for distillation. Therefore, this method may not be appropriate for de-acidification of lignin on a commercial scale . Figures 14a and 14b show water concentration in hexanol as a function of HC1 concentration in hexanol for a solution not contacted with lignin (diamonds) as well as for the wash solutions passed through the column (squares). The fact that the squares are on or below the line of diamonds indicates an absence of phase separation. Triangles in fig. 14b are wash solutions prior to loading on the column.

EXAMPLE 6:

Recovery of HC1 and water from Lignin using a counter current solvent wash; additional experiment

Example 5 was repeated using 18.5 grams of a lignin composition as summarized in table 12. Washes were conducted using solutions as summarized in table 13 and compositions of column effluent and retained lignin are summarized in table 14.

Table 12: Lignin input

Table 13: Initial composition of the washing solution of each stage

Table 14: composition of column effluent and lignin remaining in the column after each stage

lignin phase composition Wash solution composition

HCl/100 H₂O/10()

HC1 water Hexanol lignin HC1 H₂0 Hexanol

solvent solvent gr gr gr gr gr gr Wt% Wt% Wt%

initial

stage 1 22.7 4.87 6.29 9.12 2.42 33.4 24.0 31 45.0 53.4 68.9 stage 2 19 3.07 4.41 9.10 2.42 40.7 18.5 26.6 54.9 33.7 48.5 stage 3 18.9 2.47 4.04 10.0 2.42 32.9 15.0 24.5 60.5 24.8 40.5 stage 4 18.5 1.80 3.27 11.0 2.42 32.8 11.2 20.3 68.5 16.3 29.6 stage 5 17.1 1.15 2.38 11.2 2.42 6.39 7.83 16.2 76.0 10.3 21.3 After the 5 stage the lignin retained in the column was washed 3 times with ethanol. 40gr ethanol solution was recovered and analyzed for HCl and water. Results of this analysis are summarized in table 15.

Table 15: HCl and water amounts that remain with the lignin in the column after

In this example that the series of 5 washes resulted in recovery of 81% of the HCl and 77% of the water initially present in the lignin loaded in the column.

This example confirmed that there were no problems with flow through the column and establishment of equilibrium in stage 5 and that the weight of lignin did not change appreciably after each wash.

In summary, a washing strategy consistent with table 9 and/or 13 can be appropriate for de-acidification of lignin on a commercial scale. Results are summarized graphically in figures 15a and 15b which are similar to 14a and b of the previous example.

Claims

WHAT IS CLAIMED IS:

1. A lignin composition comprising :

(a) lignin;

(b) water;

(c) a first organic solvent (SI) characterized by a water solubility of less than 15% and characterized by at least one of:

(i) a polarity related component of Hoy's cohesion parameter (delta-P) between 5 and 10 MPa^1/2 ;and

(ii) a hydrogen-bond related component of Hoy's cohesion parameter (delta- H) between 5 and 20 MPa^{1 2}.

2. A composition according to claim 1, comprising HC1.

3. A composition according to claim 1 or 2, comprising at least one carbohydrate.

4. A composition according to any one of the preceding claims, wherein said lignin is solid.

5. A composition according to any one of the preceding claims, wherein SI is selected from the group consisting of alcohols, ketones and aldehydes having at least 5 carbon atoms.

6. A composition according to any one of the preceding claims, wherein SI is selected from the group consisting of hexanol, 2-ethyl-hexanol and combinations thereof.

7. A composition according to any one of the preceding claims, wherein SI has a boiling point at 1 atm of between 100°C and 200°C; and

wherein SI forms a heterogeneous azeotrope with water and said azeotrope has a boiling point at 1 atm of less than 100 ?C.

8. A composition according to any one of claims 3 to 7, wherein said carbohydrate includes one or more members selected from the group consisting of glucose, mannose, xylose, galactose, arabinose and oligosaccharides thereof with a chain length less than 11 sugar units.

9. A composition according to any one of claims 4 to 8, comprising between 5% wt and 50% wt lignin, less than 12% wt water, between 50%' wt and 90% wt of SI and less than 10% wt HCl.

10. A composition according to any one of claims 4 to 9, comprising more than 0.05% HC1.

11. A composition according to any one of claims 3 to 10, having a carbohydrate content of less than 5%wt.

12. A composition according to any one of the preceding claims, wherein the weight ratio of SI to water in the composition is Rl, and SI forms a heterogeneous azeotrope with water, and the weight ratio of SI to water in the azeotrope is R12 and Rl is greater than R12 by at least 10%, optionally 20%, optionally 30% and optionally 50%.

13. A composition according to any one of claims 4 to 12, characterized by at least one of: a solid lignin content between 3 wt% and 40 wt%, optionally between 5%wt and 30%wt and optionally between 6%wt and 25%wt;

a weight ratio of HCl to water greater than 0.3, optionally 0.4, optionally 0.5, optionally 0.6;

a weight ratio of HCl to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25;

a weight ratio of water to SI greater than 0.15, optionally 0.2, optionally 0.25, optionally 0.3, optionally 0.35; and

a weight ratio of carbohydrate to lignin less than 0.05.

14. A composition according to claim 13, comprising a single liquid phase.

15. A composition according to any one of claims 4 to 12, wherein the weight ratio of HCl to water is greater than 0.3, optionally 0.4, optionally 0.5, optionally 0.6;

wherein the weight ratio of HCl to SI is greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25; and

wherein the weight ratio of water to SI is greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25.

16. A composition according to any one of claims 4 to 13, comprising a solid lignin,

a concentrated HCl aqueous phase with a weight ratio of HCl to water greater than 0.4, optionally 0. 5, optionally 0.6; and

a phase comprising S 1 , water and HCl, with:

a weight ratio of HCl to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25, and a weight ratio of water to SI greater than 0.1, optionally 0.15, optionally 0.2, optionally 0.25.

17. An acid recovery method comprising:

(a) providing a lignin stream comprising lignin, HCl and water, wherein the weight ratio of lignin to water is in the range of 0.05 to 2 and wherein the weight ratio of HCl to water is in the range of 0.15 to 2;

(b) contacting said lignin stream with SI to form a lignin composition according to any one of claims 1 to 16; and

(c) forming de-acidified lignin.

18. A method according to claim 17, wherein said forming de-acidified lignin comprises separating S 1 from lignin.

19. A method according to claim 18, wherein said separating SI from lignin comprises at least one of decantation, filtration, centrifugation, distillation, extraction with another solvent and distillation of S 1 and water azeotrope.

20. A method according to claim 17, wherein a weight ratio of HC1 to lignin in said de- acidified lignin is less than 0.03.

21. A method according to any one of claims 17 to 20, wherein providing said lignin stream comprises hydrolyzing a lignocellulosic material in an HCl-comprising hydrolysis medium, wherein HC1 concentration in said medium is greater than azeotropic.

22. A hydrolysis method comprising:

(a) providing a lignocellulosic material feed comprising a polysaccharide and lignin;

(b) hydrolyzing said polysaccharide with HC1 to form:

a hydrolyzate comprising at least one carbohydrate and HC1; and

a lignin stream comprising lignin, HC1 and water,

(c) de-acidifying said hydrolyzate by extraction with a first extractant comprising an SI solvent, to form:

an HCl-carrying first extract; and

an HCl-depleted carbohydrate solution;

(d) recovering HC1 from said first extract

(e) de-acidifying said lignin stream according to a method of any of claims 17-21.

23. A method according to claim 22, comprising using a separated concentrated aqueous HC1 stream in said hydrolysis.

24. A method according to claim 22, wherein a lignimwater weight ratio in said lignin stream is in the range of 0.05 to 2.0 and wherein a weight/weight ratio of HC water in said lignin stream is in the range of 0.15 to 1.

25. A method according to claim 22, wherein a carbohydrates: water weight ratio in said hydrolyzate is in the range of 0.2 to 2 and wherein a weight ratio of HCl:water in said hydrolyzate is in the range of 0.17 to 0.60.

26. A method according to claim 22,- comprising extracting said HCl-depleted carbohydrate solution with a second extractant comprising an SI solvent and a second solvent S2 characterized by a water solubility of at least 30% and by at least one of :

(i) having a delta-P greater than 8 MPa^1/2; and

(ii) having a delta-H greater than 12 MPa^1/2; to form a deacidified carbohydrate solution.

A method according to claim 26, wherein S2 is selected from the group consisting of C - C₄ mono- or poly-alcohols, aldehydes and ketones and combinations thereof.

A method according to claim 26, wherein an HCl arbohydrate weight ratio in said HC1- depleted carbohydrate solution is less than 0.03.

A method according to claim 22, wherein said lignin stream comprises an impurity, wherein a ratio of impurity: lignin (W/W) in said lignin stream relative to a same weight ratio in said de-acidified lignin is greater than 1.5.

A method according to claim 17, wherein said lignin composition serves as a first evaporation feed, and comprising:

evaporating water, HC1 and SI from said first evaporation feed to produce a first vapor phase and a lignin containing phase.

A method according to claim 22, comprising :

contacting said lignin stream, with S 1 to form a first evaporation feed, and

evaporating water, HC1 and SI from said first evaporation feed to produce a first vapor phase and a lignin composition as set forth in table 1.

A method according to claim 31, wherein said evaporation is conducted at a temperature below 100°C and at a pressure below latm.

A method according to claim 31 :

wherein S 1 forms a heterogeneous azeotrope with water; and

wherein a weight ratio of Sl :water in said first evaporation feed is R13, wherein a weight ratio of SI : water in said azeotrope is R12 and wherein R13 is greater than R12 by at least 10%.

A method according to claim 17, wherein:

said lignin stream comprises solid lignin, and at least one carbohydrate; wherein:

a content of solid lignin is 5% wt to 30%wt;

a weight ratio of HC1 to water is greater than 0.5; and

a weight ratio of carbohydrate to lignin is less than 0.05;

said contacting is with an SI -comprising stream and forms a lignin composition 11 or 12 as set forth in table 1 ;

said method comprising :

separating said solid lignin to form a separated solid lignin and a separated liquid stream comprising S 1 , HC1 and water, wherein:

a weight ratio of HC1 to water is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; a weight ratio of HC1 to SI is greater than 0.1, optionally, 0.15, optionally

0.2, optionally 0.25; and

a weight ratio of water to S 1 is greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3; optionally 0.35.

35. A method according to claim 34, wherein said separated liquid stream comprises a single liquid phase.

36. A method according to claim 34, comprising distilling gaseous HC1 from said separated liquid stream to form gaseous HC1 and an HCl-depleted liquid stream.

37. A method according to claim 36, wherein providing said lignin stream comprises hydrolyzing a lignocellulosic material in an HCl-comprising hydrolysis medium and wherein said gaseous HC1 is used to form said hydrolysis medium.

38. A method according to claim 37, wherein said HCl-depleted liquid stream splits at 25°C into an HCl-depleted heavy phase, which heavy phase comprises HC1, water and SI, and into an HCl-depleted light phase, which light phase comprises HC1, water and SI, and wherein said HCl-depleted heavy phase is separated from said HCl-depleted light phase.

39. A hydrolysis method comprising:

(a) providing a lignocellulosic material feed comprising a polysaccharide and lignin wherein said lignin comprises solid lignin;

(b) hydrolyzing said polysaccharide with HC1 to form:

a hydrolyzate comprising at least one carbohydrate and HC1; and a lignin stream comprising lignin, HC1 and water,

an HCl-carrying first extract; and

an HCl-depleted carbohydrate solution;

(d) recovering HC1 from said first extract; and

(e) de-acidifying said lignin stream according to a method of any one of claims 34 to 38.

40. A method according to claim 39 wherein said lignin stream comprises carbohydrates and comprising contacting said lignin stream with an aqueous acid stream and separating to form a separated carbohydrate-depleted lignin stream and a separated carbohydrate-comprising acid stream.

41. A method according to claim 17, wherein:

said lignin stream comprises solid lignin wherein;

said solid lignin content is in the range of 5%wt to 30%wt,; an HClrwater weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and

a carbohydrate :lignin weight ratio is less than 0.05;

said contacting is with a recycled stream comprising SI, water and HCl wherein: an HClrwater weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6;

an HClrSl weight ratio is greater than 0.2; and

a waterrSl weight ratio is greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25;

said contacting forms a multi-phase composition comprising:

solid lignin;

a concentrated aqueous HCl with an HC water weight ratio greater is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and

a phase comprising SI, water and HCl with an HC water weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6, an HC1:S1 weight ratio is greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25;

and a water:Sl weight ratio is greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3, optionally 0.35;

said method comprising:

separating the multi-phase composition into at least 3 streams:

(a) a separated lignin composition as set forth in lines 15 or 16 of table 1 ;

(b) a separated concentrated aqueous HCl stream;

wherein an HChwater weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6; and

(c) a separated stream comprising S I, water and HCl, wherein:

an HChwater weight ratio is greater than 0.3, optionally, 0.4, optionally 0.5, optionally 0.6;

wherein an HC1.S1 weight ratio is greater than 0.1, optionally, 0.15, optionally 0.2, optionally 0.25; and

a watenSl weight ratio is greater than 0.15, optionally, 0.2, optionally 0.25, optionally 0.3, optionally 0.35; and

reusing the separated stream comprising SI, water and HCl from said separating as said recycled stream comprising SI, water and HCl.

42. The method according to claim 41, wherein an HCl: water ratio in said separated stream comprising SI, water and HCl is greater than a same ratio in said separated concentrated aqueous HCl stream.

43. A hydrolysis method comprising:

(b) hydrolyzing said polysaccharide with HCl to form:

a hydrolyzate comprising at least one carbohydrate and HCl; and

a lignin stream comprising lignin, HCl and water,

(c) de-acidifying said hydrolyzate by extraction with a first extractant comprising SI, to form:

an HCl-carrying first extract; and

an HCl-depleted carbohydrate solution;

(d) recovering HCl from said first extract

(e) de-acidifying said lignin stream according to a method of any of claims 41 to 42.

44. A method according to claim 17, wherein:

the weight ratio of lignin to water in said lignin stream is in the range of 0.02 to 0.25, optionally 0.1 to 0.15; and

the weight ratio of HCl to water is in the range between 0.15 and 0.32;

comprising;

i producing a lignin enriched stream by mechanically treating said lignin stream to increase said weight ratio of lignin to water to at least 0.30, optionally at least 0.35.

45. A method according to claim 44, comprising washing said lignin stream to remove soluble carbohydrates.

46. A method according to claim 45, wherein said washing employs a stream of 28 to 32 % HCl.

47. A method according to claim 45 or 46, comprising:

combining said lignin enriched stream with S 1 ; and

distilling said SI to produce a de-acidified slurry of lignin containing residual SI .

48. A method according to claim 47, comprising removing said residual SI from said slurry.

49. A method according to claim 48, wherein said removing employs centrifugation.

50. A method according to claim 48, wherein said removing includes addition of . water and distillation of the residual SI as an azeotrope with water.

51. A hydrolysis method comprising:

(b) hydrolyzing said polysaccharide with HCl to form:

a hydrolyzate comprising at least one carbohydrate and HCl; and

a lignin stream comprising lignin, HCl and water,

an HCl-carrying first extract; and

an HCl-depleted carbohydrate solution;

(d) recovering HCl from said first extract; and

(e) de-acidifying said lignin stream according to a method of any one of claims 44 to

46.

52. A system comprising:

(a) a hydrolysis vessel adapted to produce an acidic hydrolyzate containing an aqueous solution of HCl with dissolved sugars and a lignin stream including HCl and water; and

(b) an explosion proof lignin stream processing module adapted to separate said lignin from said lignin stream.

53. A system according to claim 52, comprising HCl recovery components adapted to recover said HCl from said lignin stream and deliver recovered HCl to said hydrolysis vessel.

54. A system according to claim 53, wherein said HCl recovery components include an HCl gas generator and an absorber.

55. A system according to any one of claims 52 to 54, comprising a dryer adapted to dry said lignin separated from said stream.

56. A system according to any one of claims 52 to 55, wherein said lignin stream processing module includes lignin washing equipment adapted to lower at least one of a carbohydrate and an HCl concentration in said stream.

57. A system according to any one of claims 52 to 56, wherein said lignin stream processing module includes at least one distillation unit.

58. A system according to claim 57, wherein at least one of said at least one distillation unit is a flash distillation unit.

59. A system according to any one of claims 52 to 58, wherein said lignin stream processing module is adapted to extract said lignin stream with an organic solvent. A system according to any one of claims 57-59, wherein said lignin stream processing module is adapted to heat a solvent and distill HCl from the solvent.

A system according to any one of claims 57-60, comprising one or more lignin de- solventizing components.