# US 10,870,947 B2 · Process for isolation of hemicelluloses from biomass pulping process waters or spent liquors

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- Number: US 10,870,947 B2
- Document ID: US10870947B2
- Status: Granted
- Kind: B2
- Application number: 16/326,769
- Filed: 2017-07-27
- Published: 2019-07-04
- Granted: 2020-12-22
- Earliest claimed: 2016-09-02
- Assignees: Andritz Inc.
- Applicants: Andritz AG
- Inventors: Oleg Shagaev; Lukas Wiesegger
- Web page: https://patentgrep.com/patent/US10870947B2

## CPC

- D21C 11/0007: {Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for (volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042)}
- D21C 11/0042: {Fractionating or concentration of spent liquors by special methods (concentration by evaporation D21C11/10)}
- D21C 11/04: of alkali lye
- D21C 11/10: Concentrating spent liquor by evaporation (evaporators B01D)
- Y02E 50/10: Biofuels, e.g. bio-diesel
- D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention relates to a process for isolation of hemicelluloses from biomass pulping process waters or spent liquors with removal of suspended solids, concentration of the product and purification of the product by removal of inorganic salts and low molecular weight substances. It is characterized in that the hemicellulose isolation process conditions at several separation/purification stages are adjusted separately by e.g. pH adjustment. The invention further relates to a plant for carrying out the process. With such process and plant it is possible to recover most of the suspended solids, especially xylan and other hemicelluloses.

## Claims

### Claim 1

Process for isolation of hemicelluloses from biomass pulping process waters or spent liquors with removal of suspended solids, comprising the steps of:
(a) providing an incoming stream (A) containing hemicellulose and coarse suspended solids having a size greater than 10 microns, fine suspended solids having a size within a range of 5-10 microns and colloidal substances, the incoming stream (A) having a pH;
(b) adjusting the pH of the incoming stream (A) to yield a pH-adjusted incoming stream (C) having a pH within a range of 8-11;
(c) feeding the pH-adjusted incoming stream (C) to a filtration unit for removal of coarse suspended solids (I) to produce a clear fluid stream (G) having a pH;
(d) adjusting the pH of the clear fluid stream (G) to a pH within the range of 8-11 to dissolve hemicelluloses to form a fraction (G′) having dissolved inorganic salts;
(e) removing fine solid particles having a size within a range of 5-10 microns and colloidal substances from the fraction (G′) to form an alternate fraction (J);
(f) enriching hemicelluloses in the alternate fraction (J) to form a concentrate (L);
(g) adjusting the pH of the concentrate (L) to a pH within a range of 4.0-4.5 to form a stream (N) having inorganic salts; and
(h) removing inorganic salts from the stream (N) to form a final product.

### Claim 2 (depends on 1)

The process of claim 1, wherein the final product after step (h) has a dryness of 15-30%.

### Claim 3 (depends on 2)

The process of claim 2, wherein the pH-adjusted incoming stream (C) has a pH within a range of 9.0-9.5.

### Claim 4 (depends on 2)

The process of claim 2, wherein hemicelluloses that are dissolved in step (d) are hemicelluloses that are precipitated on fine suspended solids.

### Claim 5 (depends on 4)

The process of claim 4, wherein the final product after step (h) has a dryness of 15-30%.

### Claim 6 (depends on 5)

The process of claim 5, wherein the pH-adjusted incoming stream (C) has a pH within a range of 9.0-9.5.

### Claim 7 (depends on 4)

The process of claim 4, wherein the pH-adjusted incoming stream (C) has a pH within a range of 9.0-9.5.

### Claim 8 (depends on 2)

The process of claim 2, wherein the fine solid particles having a size within a range of 5-10 micron are removed via a decanter centrifuge.

### Claim 9 (depends on 1)

The process of claim 1, wherein the pH-adjusted incoming stream (C) has a pH within a range of 9.0-9.5.

### Claim 10 (depends on 9)

The process of claim 9, wherein hem icelluloses that are dissolved in step (d) are hemicelluloses that are precipitated on fine suspended solids.

### Claim 11 (depends on 1)

The process of claim 1, wherein hemicelluloses that are dissolved in step (d) are hemicelluloses that are precipitated on fine suspended solids.

### Claim 12 (depends on 1)

The process of claim 1, wherein the fine solid particles having a size within a range of 5-10 micron are removed via a decanter centrifuge.