# US 9,751,781 B2 · Method to separate lignin-rich solid phase from acidic biomass suspension at an acidic pH

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- Number: US 9,751,781 B2
- Document ID: US9751781B2
- Status: Granted
- Kind: B2
- Application number: 14/387,169
- Filed: 2013-03-15
- Published: 2015-02-12
- Granted: 2017-09-05
- Earliest claimed: 2012-03-20
- Assignees: The Research Foundation for The State University of New York
- Applicants: The Research Foundation for The State University of New York
- Inventors: Lakshmi Rakesh Kumar Yasarla; Bandaru V. Ramarao; Thomas Amidon
- Web page: https://patentgrep.com/patent/US9751781B2

## CPC

- C02F 1/5272: {using specific organic precipitants}
- B01D 21/0012: {Settling tanks making use of filters, e.g. by floating layers of particulate material}
- B01D 21/01: using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10)
- B01D 21/262: {by using a centrifuge}
- B01D 36/045: {Combination of filters with centrifugal separation devices}
- C07G 1/00: Low-molecular-weight derivatives of lignin (high-molecular-weight derivatives of lignin {C08H6/00})
- C08H 6/00: {Macromolecular compounds derived from lignin, e.g. tannins, humic acids}
- C08H 8/00: Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)}
- C12M 45/04: {Phase separators; Separation of non fermentable material; Fractionation}
- C12M 45/09: {by enzymatic treatment}
- C12P 7/10: substrate containing cellulosic material
- C13K 13/00: Sugars not otherwise provided for in this class
- C13K 13/002: {Xylose}
- C02F 2001/007: {Processes including a sedimentation step}
- C02F 2103/26: from the processing of plants or parts thereof
- C12P 2203/00: Fermentation products obtained from optionally pretreated or hydrolyzed cellulosic or lignocellulosic material as the carbon source
- Y02E 50/10: Biofuels, e.g. bio-diesel
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07G: COMPOUNDS OF UNKNOWN CONSTITUTION (sulfonated fats, oils or waxes of undetermined constitution C07C309/62)
- C08H: DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS (polysaccharides C08B; natural rubber C08C; natural resins or their derivatives C09F; bituminous materials C10)
- C12M: APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; {APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS}
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}
- C13K: SACCHARIDES OBTAINED FROM NATURAL SOURCES OR BY HYDROLYSIS OF NATURALLY OCCURRING DISACCHARIDES, OLIGOSACCHARIDES OR POLYSACCHARIDES (chemically synthesised sugars or sugar derivatives C07H; polysaccharides, e.g. starch, derivatives thereof C08B; malt C12C; fermentation or enzyme-using processes for preparing compounds containing saccharide radicals C12P19/00; production of sucrose C13B)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method of separating a lignin-rich solid phase from a solution suspension, by pretreating a lignocellulosic biomass with a pretreatment fluid having remove soluble components, colloidal material and primarily lignin containing particles; separating the pretreated lignocellulosic biomass from the pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles; flocculating the separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles using polyethylene oxide (i.e., PEO) or cationic Poly acrylamide (i.e., CPAM) as a flocculating agent; and filtering the flocculated separated pretreatment fluid with soluble components, colloidal material and primarily lignin containing particles to remove agglomerates.

## Claims

### Claim 1

A method of separating a lignin-rich solid phase from an aqueous suspension comprising a lignocellulosic biomass having an acidic pH and aromatic components, the method comprising:
dividing the aqueous suspension comprising the lignocellulosic biomass having the acidic pH and the aromatic components into a residual lignocellulosic biomass and a suspension comprising soluble components having colloidal material and primarily lignin containing particles, said suspension having a pH less than about 4, using a pretreatment fluid;
flocculating said suspension using a sufficient amount of polyethylene oxide (PEO) as a flocculating agent, substantially without added cofactors;
adding to said suspension a precipitated calcium carbonate to raise the pH to between about 5 to 7.5; and
separating the flocculated suspension to remove agglomerates to achieve a reduction in turbidity of about 99.5%.

### Claim 2 (depends on 1)

The method according to claim 1, wherein said dividing comprises at least one method selected from the group consisting of sedimentation, centrifugation, and microfiltration.

### Claim 3 (depends on 1)

The method according to claim 1, wherein said pretreatment fluid comprises a hot water extraction fluid.

### Claim 4 (depends on 1)

The method according to claim 1, wherein said flocculating is conducted at a temperature of about 21.5° C. to about 25° C.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising fermenting a solution resulting after separating the flocculated suspension to remove agglomerates.

### Claim 6 (depends on 1)

The method according to claim 1, wherein said separating comprises filtering through a filter having a pore size of less than about 10 microns.

### Claim 7 (depends on 1)

The method according to claim 1, wherein said separating comprises filtering through at least one of a ceramic filter and a cloth filter.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the flocculating is performed for a sufficient time of less than about 2 hours to form agglomerates separable from the flocculated suspension to achieve the reduction in turbidity of about 99.5%.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the precipitated calcium carbonate is limited to an amount that does not substantially increase turbidity of the suspension.

### Claim 10

A method for treating lignocellulosic biomass comprising:
treating the lignocellulosic biomass with an extractant to extract a suspension comprising soluble components having colloidal material and primarily lignin containing particles from the lignocellulosic biomass, yielding a residual biomass and the suspension having a pH less than about 4;
separating the suspension from the residual biomass;
adding a flocculating agent to the suspension to form a flocculated suspension, wherein the flocculating agent comprises polyethylene oxide (PEO) in an amount sufficient to achieve a 99.5% reduction in turbidity after separation;
adding to the suspension a precipitated calcium carbonate to raise the pH between about 5 and 7.5; and
separating a flocculated portion of the flocculated suspension from a non-flocculated portion of the flocculated suspension to produce a fermentable solution from the lignocellulosic biomass.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the extractant comprises hot water.

### Claim 12 (depends on 10)

The method according to claim 10, wherein the suspension is separated from the residual biomass with a separation device which comprises at least one of a filter, a sedimentation tank, and a centrifuge.

### Claim 13

A method of separating a lignin-rich solid phase from a suspension comprising:
dividing a lignocellulosic biomass into a residual lignocellulosic biomass and a suspension comprising soluble components having colloidal material and primarily lignin containing particles, the suspension having a pH less than about 4, using a pretreatment fluid;
treating the suspension with a polymer flocculating agent comprising a sufficient amount of polyethylene oxide (PEO) and precipitated calcium carbonate to raise the pH to between about 5 and 7.5 and said polymer flocculating agent, being substantially without additional cofactors; and
separating the flocculated suspension to remove agglomerates to achieve a reduction in turbidity of about 99.5%.

### Claim 14 (depends on 13)

The method according to claim 13, wherein said dividing comprises at least one method selected from the group consisting of sedimentation, centrifugation, and microfiltration.

### Claim 15 (depends on 13)

The method according to claim 13, wherein said suspension comprises an aqueous suspension.

### Claim 16 (depends on 13)

The method according to claim 13, wherein said treating is conducted at a temperature of about 21.5° C. to about 25° C.

### Claim 17 (depends on 13)

The method according to claim 13, further comprising microbially processing a non-agglomerated portion of the flocculated suspension.

### Claim 18 (depends on 17)

The method according to claim 17, wherein said microbially processing comprises fermenting.

### Claim 19 (depends on 13)

The method according to claim 13, wherein said separating comprises filtering through a filter having a pore size of less than about 10 microns.

### Claim 20 (depends on 13)

The method according to claim 13, wherein said separating comprises filtering through at least one of a ceramic filter and a cloth filter.

### Claim 21 (depends on 13)

The method according to claim 13, wherein the treating is performed for less than about 2 hours.

### Claim 22 (depends on 13)

The method according to claim 13, wherein said pretreatment fluid comprises a hot water extraction fluid and said treating is conducted at a temperature of about 21.5° C. to about 25° C.

### Claim 23 (depends on 13)

The method according to claim 13, wherein the precipitated calcium carbonate is limited to an amount that does not substantially increase turbidity of the suspension.