Method and system for capturing high-purity CO2 in a hydrocarbon facility

Patent metadata

Field	Value
Publication number	US-10622656-B2
Application number	US-201715730322-A
Country	US
Kind code	B2
Filing date	Oct 11, 2017
Priority date	Oct 11, 2017
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

Embodiments of methods for capturing high-purity CO2 in a hydrocarbon facility and related systems are provided. The method comprises operating a hydrogen plant to generate a high-purity hydrogen stream and a CO2 rich stream with a CO2 concentration above 30%; introducing the high-purity hydrogen stream into an anode of a molten carbonate fuel cell; introducing the CO2 rich stream and O2 into a cathode of the molten carbonate fuel cell; reacting CO2 and O2 within the cathode to produce carbonate and a cathode exhaust stream from a cathode outlet; reacting carbonate from the cathode with H2 within the anode to produce electricity and an anode exhaust stream from an anode outlet, the anode exhaust stream comprising CO2 and H2O; separating the CO2 in the anode exhaust stream in one or more separators to form a pure CO2 stream and a H2O stream; and collecting the pure CO2 stream.

First claim

What is claimed is:

1. A method for capturing high-purity CO 2 in a hydrocarbon facility, the method comprising:
operating a hydrogen plant to generate a high-purity hydrogen stream and a CO 2 rich stream with a CO 2 concentration above 30%;
introducing the high-purity hydrogen stream into an anode of a molten carbonate fuel cell;
introducing the CO 2 rich stream and O 2 into a cathode of the molten carbonate fuel cell;
reacting CO 2 and O 2 within the cathode of the molten carbonate fuel cell to produce carbonate and a cathode exhaust stream from a cathode outlet of the molten carbonate fuel cell;
reacting carbonate from the cathode of the molten carbonate fuel cell with H 2 within the anode of the molten carbonate fuel cell to produce electricity and an anode exhaust stream from an anode outlet of the molten carbonate fuel cell, the anode exhaust stream comprising CO 2 and H 2 O;
separating the CO 2 in the anode exhaust stream in one or more separators to form a pure CO 2 stream and a H 2 O stream, the pure CO 2 stream having a purity of 80% to 100% on a molar basis; and
collecting the pure CO 2 stream.

2. The method of claim 1 , wherein the method further comprises providing the H 2 O stream from the separator to a steam reforming system to generate steam for the steam reforming system.

3. The method of claim 2 , wherein the method further comprises boosting the pressure of the H 2 O stream from the separator before introduction to the steam reforming system.

4. The method of claim 3 , wherein the pressure of the H 2 O stream is increased to at least 550 psi.

5. The method of claim 1 , wherein the method further comprises providing the cathode exhaust stream to the steam reforming system to fuel a burner in the steam reforming system with residual hydrocarbons in the cathode exhaust stream.

6. The method of claim 1 , wherein the hydrogen plant is a pressure swing adsorption system.

7. The method of claim 1 , wherein the hydrogen plant comprises an absorber and a stripper to separate CO 2 from H 2 .

8. The method of claim 1 , wherein the steam reforming system generates syngas from methane and H 2 O as a feed stream to the hydrogen plant.

9. The method of claim 1 , wherein the separator condenses the H 2 O from the anode exhaust stream to form the pure CO 2 stream and the H 2 O stream.

10. The method of claim 1 , wherein CH 4 , H 2 , CO, or combinations thereof in the CO 2 rich stream are oxidized in the cathode of the molten carbonate fuel cell to generate heat to raise the temperature of the molten carbonate fuel cell to a molten carbonate fuel cell operating temperature.

11. The method of claim 10 , wherein the molten carbonate fuel cell operating temperature is in the range of 600° C. to 700° C.

12. The method of claim 1 , wherein the O 2 introduced into the cathode of the molten carbonate fuel cell is provided as an air stream.

13. A system for capturing high-purity CO 2 in a hydrocarbon facility, the system comprising:
a hydrogen plant to generate a high-purity hydrogen stream at a high-purity hydrogen stream outlet and a CO 2 rich stream with a CO 2 concentration above 30% at a CO 2 rich stream outlet;
a molten carbonate fuel cell comprising an anode, a cathode, and a molten carbonate electrolyte; and
a separator;

wherein:
the high-purity hydrogen stream outlet is operatively connected to the anode of a molten carbonate fuel cell;
the CO 2 rich stream outlet is operatively connected to the cathode of the molten carbonate fuel cell;
an O 2 source stream is operatively connected to the cathode of the molten carbonate fuel cell;
the molten carbonate fuel cell is configured for reaction of CO 2 from the hydrogen plant and O 2 from the O 2 source stream within the cathode of the molten carbonate fuel cell to produce carbonate and a cathode exhaust stream from a cathode outlet of the molten carbonate fuel cell;
the molten carbonate fuel cell is configured for reaction of the carbonate from the cathode of the molten carbonate fuel cell with H 2 from the hydrogen plan within the anode of the molten carbonate fuel cell to produce electricity and an anode exhaust stream from an anode outlet of the molten carbonate fuel cell, the anode exhaust stream comprising CO 2 and H 2 O; and
the separator comprises a separator inlet operatively connected to the anode outlet of the molten carbonate fuel cell, a pure CO 2 outlet, and a water outlet, the separator configured to separate the anode exhaust stream to form a pure CO 2 stream and a H 2 O stream, the pure CO 2 stream having a purity of 80% to 100% on a molar basis.

14. The system of claim 13 , wherein the system further comprises a steam reforming system operatively connected to the water outlet of the separator configured to provide the H 2 O stream from the separator to the steam reforming system to generator stream for the steam reforming system.

15. The system of claim 14 , the system further comprises a pressure boosting unit configured to raise the pressure of the H 2 O stream from the separator before introduction to the steam reforming system.

16. The system of claim 15 , wherein the pressure boosting unit increases the pressure of the H2O stream to at least 550 psi before introduction to the steam reforming system.

17. The system of claim 14 , wherein the steam reforming system is further operatively connected to the cathode outlet of the molten carbonate fuel cell and is configured to provide the cathode exhaust stream to the steam reforming system to fuel a burner in the steam reforming system with residual hydrocarbons in the cathode exhaust stream.

18. The system of claim 14 , wherein the steam reforming system is operatively connected to the hydrogen plant to generate syngas from methane and H 2 O as a feed stream to the hydrogen plant.

19. The system of claim 13 , wherein the hydrogen plant is a pressure swing adsorption system.

20. The system of claim 13 , wherein the hydrogen plant comprises an absorber and a stripper to separate CO 2 from H 2 .

Assignees

• Saudi Arabian Oil Co

Inventors

• Al Hunaidy Ali Shaker
• Souentie Stamatios

Classifications

• C01B2203/148

  involving a recycle stream to the feed of the process for making hydrogen or synthesis gas · CPC title

• C01B2203/043

  Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration · CPC title

• C01B3/48

  followed by reaction of water vapour with carbon monoxide · CPC title

• C01B2203/0415

  Purification by absorption in liquids · CPC title

• H01M8/0687

  Reactant purification by the use of membranes or filters · CPC title