Methods for selectively producing hydrogen and methane from biomass feedstocks using an anaerobic biological system

• US 8,246,828 B2
• Filed: 08/04/2009
• Issued: 08/21/2012
• Est. Priority Date: 08/04/2009
• Status: Expired due to Fees

• Current Assignee: GeoSynfuels, Inc., GeoSynfuels, LLC
• Original Assignee: GeoSynfuels, LLC
• Inventors: Cheong, Dae-Yeol, Clark, Thomas R.
• Primary Examiner(s): Monshipouri, Maryam
• Application Number:
  US12/535,503
• Publication Number:
  US 20110033908A1
• Time in Patent Office: 1,113 Days
• Field of Search: 210/630, 210/603
• US Class Current: 210/603
• 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 pretreated 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 less than 85%;

d) collecting hydrogen gas from the reactor vessel at the first moisture level;

e) increasing the moisture concentration of the contents of the reactor vessel to a second moisture level greater than 90%; and

f) collecting methane gas from the reactor vessel at the second moisture level.

2. The method of claim 1, wherein step (e) comprises increasing the moisture concentration by introducing water, a liquid stream, a dilution leaching solution, steam or vapor.

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

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

5. 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.

6. The method of 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.

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

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

9. The method of claim 1, wherein the biomass is pretreated via a member selected from the group consisting of:

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

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

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