Process for fermentation of syngas from indirect gasification

• US 8,759,047 B2
• Filed: 09/16/2009
• Issued: 06/24/2014
• Est. Priority Date: 09/16/2009
• Status: Active Grant

• Current Assignee: Synata Bio, Inc.
• Original Assignee: Coskata, Inc.
• Inventors: Datta, Rathin, Corley, Ralph
• Primary Examiner(s): Marcheschi, Michael
• Assistant Examiner(s): HURST, JONATHAN M
• Application Number:
  US12/561,116
• Publication Number:
  US 20100298450A1
• Time in Patent Office: 1,742 Days
• Field of Search: 435/161
• US Class Current: 435/161
• CPC Class Codes: C01B 2203/0244 the reforming step being an autothermal reforming step, e.g. secondary reforming processes
• CPC Class Codes: C01B 2203/06 Integration with other chemical processes
• CPC Class Codes: C01B 2203/86 Carbon dioxide sequestration
• CPC Class Codes: C01B 3/382 Multi-step processes
• CPC Class Codes: C07C 29/1518 one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
• CPC Class Codes: C07C 31/04 Methanol
• CPC Class Codes: C07C 31/12 containing four carbon atoms
• CPC Class Codes: C07C 53/08 Acetic acid pyroligneous acid C10C; preparation of vinegar C12J
• CPC Class Codes: C07C 53/124 Acids containing four carbon atoms
• CPC Class Codes: C10B 49/22 according to the "fluidised bed" technique
• CPC Class Codes: C10B 53/02 of cellulose-containing material production of pyroligneous acid C10C5/00
• CPC Class Codes: C10G 2/30 from carbon monoxide with hydrogen
• CPC Class Codes: C10G 2300/1014 of vegetal origin
• CPC Class Codes: C10K 1/026 by centrifugal forces cyclones B04C
• CPC Class Codes: C10K 1/10 with aqueous liquids alkaline reacting aqueous liquids C10K1/12
• CPC Class Codes: C10K 3/008 by cracking
• CPC Class Codes: C12P 7/065 with microorganisms other than yeasts
• CPC Class Codes: C12P 7/08 produced as by-product or from waste or cellulosic material substrate
• 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
• CPC Class Codes: Y02P 20/145 : the feedstock being materials of biological origin
• CPC Class Codes: Y02P 30/00 : Technologies relating to oil refining and petrochemical industry
• CPC Class Codes: Y02P 30/20 : using bio-feedstock

Abstract

Ethanol and other liquid products are produced from biomass using indirect gasification of the biomass to produce a syngas containing CO2, CO, H2 and methane that passes the syngas without substantial removal of the methane to a fermentation zone for the conversion of the CO and CO2 and H2 to ethanol and the production of a methane rich stream followed by the methane reforming of the methane rich stream to produce additional CO and CO2 and H2 that passes to the fermentation zone.

Claims

1. A process for the production of liquid products from a biomass feedstock by indirect gasification to syngas comprising CO₂, CO, H₂ and CH₄, and bio-conversion of syngas components, said process comprising:

providing a biomass feedstock to a gasifier and indirectly gasifying the biomass feedstock by contact with a heating medium to produce a syngas stream comprising CO₂, CO, H₂ and at least 10 mole % CH₄ on an anhydrous basis;

passing a feed gas comprising the syngas stream and containing at least 10 mole % CH₄ on an anhydrous basis from the gasifier to a bioreactor to convert CO and CO₂ and H₂ to liquid products by contact with microorganisms therein;

withdrawing a bioreactor effluent stream containing the liquid products from the bioreactor and recovering liquid products from the bioreactor effluent stream;

recovering a tail gas stream from the bioreactor comprising CO₂ and CH₄;

separating CO₂ from the tail gas stream to produce a CH₄ rich gas stream;

passing at least a portion of the CH₄ rich stream to a reformer to produce a reformed stream comprising CO and CO₂ and H₂; and

,

passing at least a portion of the reformed stream to the bioreactor along with syngas from the gasifier to provide the feed gas to the bioreactor.

2. The process of claim 1 wherein the liquid products comprise at least one of ethanol, acetic acid, butanol, or butyric acid.

3. The process of claim 1 wherein a portion of the CH₄ rich stream passes to a combustion heat recovery system for the generation of power or to provide process heat.

4. The process of claim 1 wherein the gasifier comprises a gasification zone that gasifies the carbonaceous feed under substantially anaerobic conditions and a combustion zone that provides heat to the gasification zone.

5. The process of claim 1 wherein the oxygen concentration in the gasification zone is less than 1 mole %.

6. The process of claim 1 wherein the reformer comprises a partial oxidation autothermal reformer.

7. The process of claim 1 wherein the syngas undergoes clean-up for removal of water and particulates before entering the bioreactor.

8. The process of claim 1 wherein the biomass is selected from one or more the group consisting of wood, miscanthus, switchgrass, sugar cane bagasse, corn stover and urban waste.

9. The process of claim 1 wherein the liquid products comprise ethanol.

10. The process of claim 7 wherein the microorganisms in the bioreactor comprises a mono-culture or a co-culture of at least one of Clostridium ragsdalei, Butyribacterium methylotrophicum, Clostridium Ljungdahlii, Clostridium Autoethanogenum, Clostridium Woodii and Clostridium carboxydivorans.

11. The process of claim 1 wherein the syngas on an anhydrous basis comprises 20 to 45 mole % H₂, 15 to 50 mole % CO, 10 to 20 mole % CH₄, and 10 to 20 mole % CO₂ and the tail gas comprises at least 25 mole % CH₄ and at least 50 mole % CO₂.

12. The process of claim 1 wherein the gasifier operates with a temperature of less than 900°

C. and a pressure of less than 4 bars absolute.

13. A process for the production of ethanol from a biomass feedstock by indirect gasification to syngas comprising CO₂, CO, H₂ and CH₄, and bio-conversion of syngas components, said process comprising:

providing a biomass feedstock to a gasifier and indirectly gasifying the biomass feedstock by contact with a heating medium at a temperature of less than 900°

C. and a pressure of less than 4 bars absolute to produce a syngas stream comprising CO₂, CO, H₂ and at least 10 mole % of CH₄ on an anhydrous basis;

passing a feed gas comprising syngas and containing at least 10 mole % CH₄ on an anhydrous basis from the gasifier to a bioreactor to convert CO and CO₂ and H₂ to ethanol by contact with microorganisms therein;

withdrawing a bioreactor effluent stream containing ethanol from the bioreactor and separating the ethanol in a ethanol recovery section to produce an ethanol product;

recovering a tail gas stream from the bioreactor comprising on an anhydrous basis at least 40 mole % CO₂ and 25 mole % CH₄;

separating CO₂ from the tail gas stream to produce a CH₄ rich gas stream;

passing a portion of the CH₄ rich gas stream to a combustion heat recovery system for the generation of power or to provide process heat;

passing at least a portion of the CH₄ rich stream to an autothermal reformer to produce a reformed stream comprising CO and CO₂ and H₂; and

,

passing at least a portion of the reformed stream to the bioreactor along with syngas from the gasifier to provide the feed gas to the bioreactor.