METHODS FOR SELECTIVELY PRODUCING HYDROGEN AND METHANE FROM BIOMASS FEEDSTOCKS USING AN ANAEROBIC BIOLOGICAL SYSTEM

• US 20110033908A1
• Filed: 08/04/2009
• Published: 02/10/2011
• Est. Priority Date: 08/04/2009
• Status: Active Grant

• Current Assignee: GeoSynfuels, Inc., GeoSynfuels, LLC
• Original Assignee: GeoSynfuels, LLC
• Inventors: Clark, Thomas R., Cheong, Dae-Yeol
• Granted Patent: US 8,246,828 B2
• Time in Patent Office: Days
• US Class Current: 435/167
• CPC Class Codes: C12M 21/04 for producing gas, e.g. biogas digesters for manure with production of biogas A01C3/028, biological treatment of water, waste water or sewage C02F3/00, C02F11/02, preparation of natural gas or syngas C10L3/06, C10L3/10
• CPC Class Codes: C12M 41/34 of gas
• CPC Class Codes: C12P 3/00 Preparation of elements or inorganic compounds except carbon dioxide recovery of carbon dioxides as by-products C12F3/02
• CPC Class Codes: C12P 5/023 Methane
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

The present invention provides a method for selective production of hydrogen and methane from a biomass feedstock in a reactor vessel maintained under anaerobic conditions by controlling moisture concentration in the reactor vessel. The method comprises the steps of introducing a biomass feedstock into the reactor vessel maintained under anaerobic conditions; introducing a bacterial inoculum into the reactor vessel to facilitate digestion of the biomass feedstock; setting a moisture concentration of the contents of the reactor vessel at a first moisture level; and collecting hydrogen gas from the reactor vessel. The method may further comprise maintaining the moisture concentration at a first moisture level or within a first moisture range. The method may additionally comprise increasing the moisture concentration of the contents of the reactor vessel to a second moisture concentration; and collecting methane gas from the reactor vessel. Switching between hydrogen and methane production is controlled by adjusting the moisture concentration of the contents of the reactor vessel.

Claims

1. A method for selective production of hydrogen and methane from a biomass feedstock in a reactor vessel maintained under anaerobic conditions, the method comprising:

a) introducing a biomass feedstock into a reactor vessel maintained under anaerobic conditions;

b) introducing a bacterial inoculum into the reactor vessel to facilitate digestion of the biomass feedstock;

c) setting a moisture concentration of contents of the reactor vessel at a first moisture level; and

d) collecting hydrogen gas from the reactor vessel.

2. The method of claim 1, further comprising maintaining the moisture concentration at a first moisture level or within a first moisture range.

3. The method of claim 1, wherein the method further comprises:

e) increasing the moisture concentration of the contents of the reactor vessel to a second moisture level; and

f) collecting methane gas from the reactor vessel.

4. The method of claim 3, wherein step (e) comprises increasing the moisture concentration by introducing water, a liquid stream, a dilution leaching solution, steam or vapor.

5. The method of claim 1, wherein there is no chemical agent or heat pretreatment to enrich the bacterial inoculum.

6. The method of claims claim 1, wherein the first moisture concentration of the contents of the reactor vessel is less than 85%.

7. The method of claim 1, wherein the first moisture concentration of the contents of the reactor is less than 80%.

8. The method of claim 3, wherein the second moisture concentration of the contents of the reactor vessel is greater than 90%.

9. The method of claim 1, further comprising maintaining a pH level of the contents of the reactor vessel at a first pH level or within a first pH range.

10. The method claim 1, wherein the biomass feedstock is selected from the group consisting of:

plant material, animal material, food water, industrial waste, and organic waste products or residual thereof.

11. The method of claim 1, wherein the biomass feedstock comprises cellulose.

12. The method of claim 1, wherein the biomass feedstock is non-sterile.

13. The method of claim 1, wherein the biomass feedstock is pretreated.

14. The method of claim 13, wherein the pretreatment is a member selected from the group consisting of:

acid treatment, steam explosion, and ammonia fiber-freeze explosion.

15. The method of claim 1, wherein the biomass feedstock is a residue obtained from a process to produce ethanol.

16. The method of claim 1, wherein the biomass feedstock and the bacterial inoculum are introduced into the reactor vessel substantially at the same time.

17. A system for performing the method of claim 1, the system comprising:

a reactor vessel maintained under anaerobic conditions configured to receive biomass feedstock and a bacterial inoculum;

a moisture monitor/controller configured to monitor and/or control a moisture level of contents of the reactor vessel;

a gas collector configured to collect hydrogen and/or methane produced in the reactor vessel from digestion of the biomass feedstock;

optionally, a pH monitor/controller configured to monitor and/or control pH of the contents of the reactor vessel; and

optionally, a biomass pretreater configured to pretreat the biomass feedstock prior to introduction into the reactor vessel.