Power generation and CO2 capture with turbines in series

Patent metadata

Field	Value
Publication number	US-9556753-B2
Application number	US-201414486200-A
Country	US
Kind code	B2
Filing date	Sep 15, 2014
Priority date	Sep 30, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

In various aspects, a method for producing electricity by operating two or more turbines in series is provided. The method can include introducing, at least part of, the exhaust from an upstream turbine into a combustion chamber of a downstream turbine. In one aspect, exhaust from the upstream turbine is introduced into the downstream turbine's combustion chamber via the downstream turbine's compression chamber.

First claim

What is claimed is:

1. A method for producing electricity, the method comprising:
introducing a first oxygen stream and a first combustion fuel stream into a combustion chamber of a first combustion turbine;
generating electricity and a first exhaust gas by combusting the first combustion fuel stream in the first combustion turbine, the first exhaust gas having first exhaust concentration of O 2 and a first exhaust concentration of CO 2 ;
introducing at least about 50 mol % of the O 2 and at least about 50 mol % of the CO 2 from the first exhaust gas into a combustion chamber of a second combustion turbine;
introducing a second combustion fuel stream into the combustion chamber of the second combustion turbine;
generating electricity and a second exhaust gas by combusting the second combustion fuel stream in the second combustion turbine, the second exhaust gas having second exhaust concentration of O 2 and a second exhaust concentration of CO 2 , a ratio of the second exhaust concentration of CO 2 to the first exhaust concentration of CO 2 being at least about 1.3:1; and
separating CO 2 from at least a portion of the second exhaust gas, comprising:
introducing the at least a portion of the second exhaust gas into a cathode of a molten carbonate fuel cell;
introducing an anode fuel stream comprising a reformable fuel into an anode of the molten carbonate fuel cell, an internal reforming element associated with the anode, or a combination thereof;
generating electricity within the molten carbonate fuel cell; and
generating an anode exhaust from the molten carbonate fuel cell comprising H 2 , CO, and CO 2 .

2. The method of claim 1 , wherein the first exhaust gas has a mole fraction of CO 2 of at least about 3%.

3. The method of claim 1 , wherein the second exhaust gas has a mole fraction of CO 2 of at least about 6%.

4. The method of claim 1 , wherein the method further comprises introducing the first exhaust gas into a heat recovery and steam generator prior to said introducing of at least a portion of the exhaust gas into the second combustion turbine.

5. The method of claim 1 , wherein the method further comprises adding air to the first exhaust gas prior to said introducing of the at least about 50 mol % of the O 2 and the at least about 50 mol % of the CO 2 from the first exhaust gas into the combustion chamber of the second combustion turbine.

6. The method of claim 1 , wherein a ratio of the second exhaust concentration of CO 2 to the first exhaust concentration of CO 2 is at least about 1.7:1.

7. The method of claim 1 , wherein the first exhaust concentration of O 2 is less than about 15 mol % and the second exhaust concentration of O 2 is less than about 7 mol %.

8. The method of claim 1 , further comprising performing a water gas shift process on at least a portion of the anode exhaust.

9. The method of claim 1 , further comprising separating CO 2 from at least a portion of the anode exhaust.

10. The method of claim 1 , wherein one or more of the first combustion fuel stream, the second combustion fuel stream, and the anode fuel stream comprising a reformable fuel, each comprise at least about 10 vol % CO 2 .

11. The method of claim 1 , further comprising forming an H 2 -containing stream from at least a portion of the anode exhaust.

12. The method of claim 1 , wherein methane comprises at least about 90 vol % of the first combustion fuel stream, the second combustion fuel stream, the anode fuel stream comprising a reformable fuel, or a combination thereof.

13. The method of claim 1 , wherein the fuel cell is operated at a thermal ratio of about 0.25 to about 1.0.

14. The method of claim 1 , wherein an amount of the reformable fuel introduced into the anode, the reforming stage associated with the anode, or the combination thereof, is at least about 75% greater than an amount of hydrogen reacted in the molten carbonate fuel cell to generate electricity.

15. The method of claim 1 , wherein the fuel cell is operated to generate electrical power at a current density of at least about 150 mA/cm 2 and at least about 40 mW/cm 2 of waste heat, the method further comprising performing an effective amount of an endothermic reaction to maintain a temperature differential between the anode inlet and an anode outlet of about 100° C. or less.

16. The method of claim 1 , wherein an electrical efficiency for the fuel cell is between about 10% and about 40% and a total fuel cell efficiency for the fuel cell is at least about 55%.

17. The method of claim 1 , wherein at least about 90 mol % of the CO 2 from the first exhaust gas is introduced into the combustion chamber of the second combustion turbine.

18. The method of claim 1 , wherein at least about 99 mol % of the CO 2 from the first exhaust gas is introduced into the combustion chamber of the second combustion turbine.

19. The method of claim 1 , wherein a remaining portion of the O 2 and the CO 2 from the first exhaust gas is recycled to the combustion zone of the first combustion turbine.

Assignees

• Barckholtz Timothy A
• Hershkowitz Frank H
• Berlowitz Paul J
• Exxonmobil Res & Eng Co

Inventors

• Barckholtz Timothy A
• Hershkowitz Frank H
• Berlowitz Paul J

Classifications

• H01M2008/147

  Fuel cells with molten carbonates · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title

• F02C3/22

  the fuel or oxidant being gaseous at standard temperature and pressure (F02C3/28 takes precedence) · CPC title

• F02C6/00

  Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use · CPC title

• F05D2260/61

  Removal of CO2 · CPC title