Carbon dioxide recovery

Patent metadata

Field	Value
Publication number	US-10315150-B2
Application number	US-201815883614-A
Country	US
Kind code	B2
Filing date	Jan 30, 2018
Priority date	Mar 8, 2013
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

The present techniques are directed to a system and method for recovering carbon dioxide (CO2). The method includes recovering the CO2 from a gas mixture including the CO2 via a CO2 separation system. The CO2 separation system includes a rotating freezer/melter.

First claim

What is claimed is:

1. A method for recovering carbon dioxide (CO 2 ), comprising:
receiving, in a CO 2 separation system, a gas mixture from a power plant, wherein the gas mixture comprises CO 2 , and the CO 2 separation system comprises:
a rotating freezer/melter having a freezing zone, a melting zone, and a rotor;
a CO 2 separation device downstream of the freezing zone of the rotating freezer/melter; and
a compressor downstream of the CO 2 separation device;

flowing the gas mixture through the rotor while the rotor is in the freezing zone;
capturing solid CO 2 from the gas mixture on the rotor while the rotor is in the freezing zone;
melting the solid CO 2 captured on the rotor while the rotor is in the melting zone, thereby forming liquid CO 2 ;
flowing the liquid CO 2 through the rotor while the rotor is in the melting zone;
maintaining the melting zone at a higher pressure than the freezing zone to preserve the melted CO 2 in a liquid state as it exits the melting zone;
routing the remaining gas mixture out of the freezing zone and into the CO 2 separation device;
recovering residual CO 2 from the remaining gas mixture using the CO 2 separation device;
pressurizing the residual CO 2 using the compressor to produce a pressurized CO 2 vapor stream; and
using the pressurized CO 2 vapor stream to melt the solid CO 2 within the melting zone of the rotating freezer/melter.

2. The method of claim 1 , further comprising pumping at least a portion of the melted CO 2 using a pump disposed downstream of the rotating freezer/melter, thereby generating pressurized liquid CO 2 .

3. The method of claim 2 , further comprising converting the pressurized liquid CO 2 to a vapor CO 2 stream using a refrigeration load.

4. The method of claim 3 , further comprising using the refrigeration load to chill cooling water for the power plant.

5. The method of claim 3 , further comprising using the vapor CO 2 stream in enhanced oil recovery (EOR) operations.

6. The method of claim 1 , further using a dehydration system to remove H 2 O from the gas mixture prior to receiving the gas mixture in the CO 2 separation system.

7. The method of claim 1 , wherein the CO 2 separation system further comprises a heat exchanger and a first expander.

8. The method of claim 7 , further comprising, prior to flowing the gas mixture through the rotor:
cooling the gas mixture using the heat exchanger; and
flowing the gas mixture through the first expander, thereby forming solid CO 2 from at least a portion of the CO 2 in the gas mixture.

9. The method of claim 8 , wherein the gas mixture is cooled via indirect heat exchange.

10. The method of claim 8 , further comprising flowing the remaining gas mixture to the heat exchanger prior to routing the remaining gas mixture to the CO 2 separation device, wherein the heat exchanger cools the gas mixture via indirect exchange with the remaining gas mixture.

11. The method of claim 8 , wherein the first expander lowers the pressure and temperature of the gas mixture thereby freezing at least a portion of CO 2 within the gas mixture to pure solid CO 2 .

12. The method of claim 1 , wherein the CO 2 separation device recovers the residual CO 2 from the remaining gas mixture via a potassium carbonate separation process.

13. The method of claim 1 , further comprising:
recycling a portion of the liquid CO 2 to the melting zone of the rotating freezer/melter; and
using the portion of the liquid CO 2 to melt the solid CO 2 within the melting zone.

14. The method of claim 1 , wherein an exhaust gas from the power plant provides the gas mixture.

15. The method of claim 1 , comprising producing power via the power plant.

16. The method of claim 15 , wherein producing power via the power plant comprises:
providing mechanical energy via an expander turbine using energy extracted from the gas mixture after combustion of the gas mixture in a combustor; and
generating electricity via a generator using the mechanical energy provided by the expander turbine.

17. The method of claim 15 , wherein producing the power via the power plant comprises:
providing mechanical energy via an expander turbine using energy extracted from the gas mixture after combustion of the gas mixture in a combustor;
generating steam via a heat recovery steam generator (HRSG) by heating a boiler with an exhaust stream from the expander turbine;
providing mechanical energy via a steam turbine using energy extracted from the steam generated by the HRSG; and
generating electricity via a generator using the mechanical energy provided by the expander turbine and the steam turbine.

18. The method of claim 1 , further comprising recycling a portion of the gas mixture to the power plant.

Assignees

• Huntington Richard A
• Denton Robert D
• Dhanuka Sulabh K
• Exxonmobil Upstream Res Co

Inventors

• Huntington Richard A
• Denton Robert D
• Dhanuka Sulabh K

Classifications

• F23J2900/15061

  Deep cooling or freezing of flue gas rich of CO2 to deliver CO2-free emissions, or to deliver liquid CO2 · CPC title

• F23J15/06

  of coolers · CPC title

• B01D53/75

  Multi-step processes · CPC title

• C10L3/104

  Carbon dioxide · CPC title

• F25J3/0266

  separation of carbon dioxide (production of carbon dioxide in general C01B32/00) · CPC title