Method of converting biomass

• US 20190316051A1
• Filed: 07/03/2017
• Published: 10/17/2019
• Est. Priority Date: 07/01/2016
• Status: Active Grant

• Current Assignee: CH-Bioforce Oy
• Original Assignee: CH-Bioforce Oy
• Inventors: Vahasalo, Lari, Lax, Nicholas, Von Schoultz, Sebastian
• Granted Patent: US 11,001,777 B2
• Time in Patent Office: Days
• CPC Class Codes: C10L 2230/14 for improving storage or transport of the fuel
• CPC Class Codes: C10L 2230/22 for improving fuel economy or fuel efficiency
• CPC Class Codes: C10L 2290/08 Drying or removing water
• CPC Class Codes: C10L 2290/146 of water
• CPC Class Codes: C10L 2290/148 of steam
• CPC Class Codes: C10L 2290/28 Cutting, disintegrating, shredding or grinding
• CPC Class Codes: C10L 2290/30 Pressing, compressing or compacting
• CPC Class Codes: C10L 2290/544 Extraction for separating fractions, components or impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 5/442 Wood or forestry waste
• CPC Class Codes: C10L 9/08 by heat treatments, e.g. calcining
• CPC Class Codes: D21C 1/02 with water or steam
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

Increasing of the heating value of combustible biomass through hemicellulose extraction and subsequent press-drying is described. After hemicellulose extraction the remaining biomass is soft and easily press-dried to high dry content of up to 80%. The method involves the removal of most water binding hemicelluloses and retaining most of the lignin in the biomass. Lignin can either be retained in the biomass during the extraction or combining the lignin, which has been separated from the hemicellulose extract, with the extracted biomass.

Claims

1. A method of producing a modified biomass composition having a high heating value, comprising the steps of

providing biomass, such as fresh biomass, containing cellulose, lignin and hemicelluloses;

subjecting the biomass to a step of hot water extraction at a pre-determined temperature in excess of 100°

C.;

continuing the hot water extraction so as to remove at least 50 weight-% of hemicelluloses and less than 10 weight-% of lignin from the biomass so as to produce an extracted biomass;

recovering the extracted biomass; and

subjecting the warm, extracted biomass to press-drying so as to achieve a biomass having dry matter content which is higher than 50 weight-%.

2. The method according to claim 1, further comprising press-drying the biomass which has a surface temperature of more than 30°

C., in particular at least 40°

C.

3. The method according to claim 1, further comprising press-drying biomass which has not been cooled down to a surface temperature below 35°

C., in particular below 40°

C., between the extraction and the press-drying steps.

4. The method according to claim 1, wherein the biomass is press-dried to a dry matter content which is higher than the maximum dry matter content of press dried fresh lignocellulosic biomass.

5. The method according to claim 1, further comprising carrying out the step of hot water extraction by removing at least 60 weight-% of hemicelluloses from the biomass by hot water extraction at a maximum temperature of 160°

C., preferably at 135-160°

C., and then press drying the resulting biomass.

6. The method according to claim 1, further comprising carrying out the step of hot water extraction by removing at least 50 weight-%, in particular at least 60 weight-%, of hemicelluloses from the biomass by hot water extraction.

7. The method according to claim 1, wherein the biomass is subjected to hot water extraction at a minimum temperature in excess of 160°

C., in particular at a temperature of up to 220°

C.

8. The method according to claim 1, further comprising

carrying out the step of hot water extraction by

removing at least 60 weight-% of hemicelluloses from the biomass by hot water extraction;

and

precipitating dissolved lignin from the extraction solution back onto the extracted biomass; and

press-drying the resulting biomass to a dry content of at least 60 weight-%.

9. The method according to claim 1, further comprising removing hemicelluloses from the biomass in an oxygen starved environment using an aqueous extraction solution, in particular hemicelluloses are removed from the biomass in an environment, in which oxygen concentration is lower than 0.1 kg oxygen/kg of said aqueous extraction solution, in order to hinder oxidative reactions in the biomass during the hot water extraction.

10. The method according to claim 1, further comprising extracting hemicelluloses from the biomass using an aqueous solution in which the amount of oxygen is less than 0.01 kg oxygen/kg of said aqueous solution, preferably less than 0.005 kg oxygen/kg of said aqueous solution, in particular less than 0.0001 kg oxygen/kg of said aqueous solution during extraction.

11. The method according to claim 1, wherein lignin is precipitated in or from a hemicellulose-containing aqueous solution of hot water extraction, by the step of

a) adding a lignin precipitating chemical to the solution;

or

b) lowering the temperature of the extraction solution below the solubility of lignin;

or

c) a combination of steps a and b.

12. The method according to claim 1, wherein the extracted biomass is press-dried to a dry content of 60 to 90 weight-%.

13. The method according to claim 1, wherein the lignocellulosic biomass, in particular the fresh lignocellulosic biomass, comprises wood, in particular the biomass is formed by chips or saw dust, preferably crushed chips.

14. The method according to claim 1, further comprising recovering biomass having, at a pre-determined dry matter content, a heating value which is at least 10% higher than the heating value of the corresponding untreated lignocellulosic biomass, at the same dry matter content.

15. Lignocellulosic biomass having a dry content of at least 90 weight-%, said biomass containing less than 50% of the hemicelluloses and at least 90 weight-% of the lignin of the corresponding fresh lignocellulosic biomass, and preferably at least 90 weight-% of the cellulose of the corresponding fresh lignocellulosic biomass.

16. Use of the lignocellulosic biomass having a dry content of at least 90 weight-%, said biomass containing less than 50% of the hemicelluloses and at least 90 weight-% of the lignin of the corresponding fresh lignocellulosic biomass, and preferably at least 90 weight-% of the cellulose of the corresponding fresh lignocellulosic biomass,

as a raw material for energy production;

or

as a fuel.