PROCESS FOR TREATMENT OF BIOMASS FEEDSTOCKS

• US 20090098251A1
• Filed: 11/09/2005
• Published: 04/16/2009
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: The Michigan Biotechnology Institute
• Original Assignee: The Michigan Biotechnology Institute
• Inventors: Rajagopalan, Srinivasan, McCalla, Darold, Tiedje, Tonya
• Granted Patent: US 7,937,851 B2
• Time in Patent Office: Days
• US Class Current: 426/69
• CPC Class Codes: F26B 1/00 Preliminary treatment of solid materials or objects to facilitate drying , e.g. mixing or backmixing the materials to be dried with predominantly dry solids F26B5/005 takes precedence
• CPC Class Codes: F26B 21/14 using gases or vapours other than air or steam , e.g. inert gases
• CPC Class Codes: F26B 25/006 Separating volatiles, e.g. recovering solvents from dryer exhaust gases
• CPC Class Codes: F26B 7/00 Drying solid materials or objects by processes using a combination of processes not covered by a single one of groups F26B3/00 and F26B5/00 F26B1/005, F26B5/04, F26B23/026 take precedence

Abstract

A method and apparatus for continuously treating a moist biomass feedstock is disclosed. The method includes treating a biomass feedstock with a swelling agent in a pressurized first vessel, transferring the feedstock to a second vessel at a lower operating pressure than the first vessel such that the biomass fibers rupture. At least portions the swelling agent, and/or the moisture are recycled in the process.

Claims

1. A method for continuously treating a moist biomass material, comprising:

rupturing a biomass material by vaporizing a swelling agent to provide a first vapor stream;

drying the ruptured biomass material to provide a second vapor stream containing at least a portion of the swelling agent and moisture from the ruptured biomass material and a dried biomass;

condensing the second vapor stream; and

using the condensed second vapor stream to treat biomass material before the biomass material is ruptured.

6. The method of claim 1, 2 or 3, wherein the swelling agent is ammonia.

7. The method of claim 1, 2 or 3, wherein the biomass material includes material selected from the group consisting of corn stover, wheat straw, alfalfa, grass, rice straw, corn fiber, distiller'"'"'s dried grains with solids, switchgrass, bagasse, and mixtures thereof.

22. The method of claim 1, 2 or 3, wherein the ruptured biomass is dried under partial vacuum.

2. A method for continuously treating a moist biomass material, comprising:

rupturing a biomass material by vaporizing a swelling agent to provide a first vapor stream;

condensing the first vapor stream;

retaining the condensed first vapor stream in a storage tank;

using the condensed first vapor stream to treat biomass material before the biomass material is ruptured;

drying the ruptured biomass material to provide a second vapor stream and a dried biomass;

condensing the second vapor stream; and

using the condensed second vapor stream to treat biomass material before the biomass material is ruptured.

3. A method for continuously treating a moist biomass material, comprising:

contacting the biomass material with a swelling agent under a pressure sufficient to prevent vaporization of the swelling agent and for a time sufficient to allow the swelling agent to swell fibers within the biomass material;

rupturing the biomass material by vaporizing the swelling agent to provide a first vapor stream;

drying the ruptured biomass material to provide a second vapor stream and a dried biomass,

condensing the second vapor stream; and

using the condensed second vapor stream to treat biomass material before the biomass material is ruptured.

4. The method of claim 3, wherein the step of rupturing the biomass material comprises transferring the biomass material from a reactor to a vessel having a pressure sufficiently less than that of the reactor such that at least a portion of the swelling agent vaporizes and exits the vessel through a vapor outlet, causing the biomass fibers to rupture.

5. The method of claim 4, wherein the biomass is ruptured by adiabatically flashing the biomass material exiting the reactor.

8. A method for continuously treating biomass material, comprising:

contacting the biomass material and a swelling agent in a first vessel under a pressure sufficient to prevent vaporization of the swelling agent and for a time sufficient to allow the swelling agent to swell fibers within the biomass material; and

transferring the biomass material to a second vessel having a pressure sufficiently less than that of the first vessel such that at least a portion of the swelling agent rapidly vaporizes, causing the biomass fibers to rupture;

wherein the first vessel is pressurized with a first stream including vaporized swelling agent to a pressure sufficient to prevent vaporization of the swelling agent in the first vessel.

9. A method for continuously treating biomass material, comprising:

contacting the biomass material and a swelling agent in a first vessel under a pressure sufficient to prevent vaporization of the swelling agent and for a time sufficient to allow the swelling agent to swell fibers within the biomass material; and

transferring the biomass material to a second vessel having a pressure sufficiently less than that of the first vessel such that at least a portion of the swelling agent rapidly vaporizes, causing the biomass fibers to rupture, wherein the first vessel is pressurized with a first stream including vaporized swelling agent to a pressure sufficient to prevent vaporization of the swelling agent in the first vessel;

drying the biomass material to provide a second vapor stream and a dry biomass;

condensing the second vapor stream; and

using the condensed second vapor stream to treat the biomass material before the biomass material enters the first vessel.

10. The method of claim 9, wherein the second vapor stream includes ammonia and water.

11. The method of claim 9, wherein the second stream includes vaporized swelling agent that is at least partially obtained from the second vessel.

12-21. -21. (canceled)