Fischer-tropsch tail-gas utilization

• US 20030083390A1
• Filed: 10/23/2001
• Published: 05/01/2003
• Est. Priority Date: 10/23/2001
• Status: Abandoned Application

• Current Assignee: TEXACO, INC. AND TEXACO DEVELOPMENT CORPORATION
• Original Assignee: TEXACO, INC. AND TEXACO DEVELOPMENT CORPORATION
• Inventors: Song, Rae, Quintana, Manual E., Thacker, Pradeep S., Shah, Lalit S.
• Application Number:
  US10/001,820
• Publication Number:
  US 20030083390A1
• Time in Patent Office: Days
• US Class Current: 518/702
• CPC Class Codes: C01B 2203/0255 containing a non-catalytic partial oxidation step
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/062 Hydrocarbon production, e.g. Fischer-Tropsch process
• CPC Class Codes: C01B 3/36 using oxygen or mixtures containing oxygen as gasifying agents
• CPC Class Codes: C10G 2/32 with the use of catalysts
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0973 Water
• CPC Class Codes: C10J 2300/1659 to liquid hydrocarbons
• CPC Class Codes: C10J 2300/1671 with the production of electricity
• CPC Class Codes: C10J 2300/1807 Recycle loops, e.g. gas, solids, heating medium, water

Abstract

The present invention deals with the handling of the tail-gas product from an integrated gasification reactor/Fischer-Tropsch reactor unit. The Fischer-Tropsch tail-gas is either recycled back for feed to the gasification unit to be converted into syngas, is processed in a CO₂ removal unit and recycled back to the feed of the Fischer-Tropsch reactor to improve the liquid product yield, or is sent to a power production unit for the generation of electric power.

Claims

1. A hydrocarbon synthesis process comprising:

(a) forming a synthesis gas by reacting a combustible carbonaceous material and a tail-gas with

     1) steam and/or water and

     2) oxygen or air or enriched air at an elevated temperature in a gasification reactor;

(b) contacting the said synthesis gas with a hydrocarbon synthesis catalyst to form liquid hydrocarbons and the tail-gas in hydrocarbon synthesis reactor;

(c) separating the resulting tail-gas and the liquid hydrocarbons; and

(d) recycling the tail-gas back the reactor.

2. The process of claim 1 comprising the additional step of removing carbon dioxide from a fraction of the tail-gas and mixing the carbon dioxide-free tail-gas fraction with the synthesis gas prior to contacting the synthesis gas with the hydrocarbon synthesis catalyst.

3. The process of claim 1 comprising the additional step of combusting a fraction of the tail-gas and generating power from said combusted fraction.

4. The process of claim 3 comprising the additional step of removing carbon dioxide from a second fraction of the tail-gas and mixing the carbon dioxide-free tail-gas second fraction with the synthesis gas prior to contacting the synthesis gas with the hydrocarbon synthesis catalyst.

5. A method for consuming a tail-gas produced by reacting a synthesis gas with a hydrocarbon synthesis catalyst comprising reacting the tail-gas and a combustible carbonaceous material with steam and oxygen at an elevated temperature to form the synthesis gas.

6. The method of claim 5 comprising the additional step of removing carbon dioxide from a fraction of the tail-gas and mixing the carbon dioxide-free tail-gas fraction with the synthesis gas prior to reacting the synthesis gas with the hydrocarbon synthesis catalyst.

7. The method of claim 5 comprising the additional step of combusting a fraction of the tail-gas and generating power from said combusted fraction.

8. The method of claim 7 comprising the additional step of removing carbon dioxide from a second fraction of the tail-gas and mixing the carbon dioxide-free tail-gas second fraction with the synthesis gas prior to reacting the synthesis gas with the hydrocarbon synthesis catalyst.