Staged pressure swing adsorption for simultaneous power plant emission control and enhanced hydrocarbon recovery

Patent metadata

Field	Value
Publication number	US-10071338-B2
Application number	US-201615339978-A
Country	US
Kind code	B2
Filing date	Nov 1, 2016
Priority date	Nov 17, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

Systems and methods for using pressure swing adsorption to separate and/or capture resulting emissions are provided. A stream of recycled exhaust gas is passed into a first swing adsorption reactor comprising a first adsorbent material which adsorbs CO 2 . An enriched N 2 stream is recovered from a forward end of the first swing adsorption reactor. The pressure in the first swing adsorption reactor is reduced. The first swing adsorption reactor is purged with a portion of the first N 2 stream recovered from the first swing adsorption reactor. The first purge output is passed to a second swing adsorption reactor comprising a second adsorbent material which adsorbs CO 2 . A second N 2 stream is recovered from the second swing adsorption reactor. The pressure in the second swing adsorption reactor is reduced. The second swing adsorption reactor is purged with a steam purge.

First claim

The invention claimed is:

1. A method for capturing emissions comprising:
passing a stream of recycled exhaust gas into a first swing adsorption reactor comprising a first adsorbent material;
adsorbing CO 2 on the first adsorbent material;
recovering a first N 2 stream from a forward end of the first swing adsorption reactor wherein the first N 2 stream is an enriched N 2 stream;
reducing the pressure in the first swing adsorption reactor by outputting a blow down stream from at least one end of the first swing adsorption reactor;
purging the first swing adsorption reactor with a portion of the first N 2 stream recovered from the first swing adsorption reactor to create a first purge output from the first swing adsorption reactor;
passing the first purge output to a second swing adsorption reactor comprising a second adsorbent material;
adsorbing CO 2 on the second adsorbent material;
recovering a second N 2 stream from a forward end of the second swing adsorption reactor;
reducing the pressure in the second swing adsorption reactor by outputting a blow down stream from at least one end of the second swing adsorption reactor; and
purging the second swing adsorption reactor with a steam purge to create an output from the second swing adsorption reactor.

2. The method of claim 1 , wherein reducing the pressure in the first swing adsorption reactor comprises reducing the pressure to an intermediate pressure value lower than a pressure value of the recycled exhaust gas and higher than a pressure value of the output from the second swing adsorption.

3. The method of claim 2 , wherein the intermediate pressure value is between 3 and 12 bar.

4. The method of claim 1 , wherein at least one of the first swing adsorption reactor and the second swing adsorption reactor comprises multiple adsorbent beds.

5. The method of claim 4 , wherein adsorption of CO 2 by the multiple adsorbent beds is cycled to allow regeneration of at least one bed without completely ceasing adsorption.

6. The method of claim 1 , wherein the first adsorbent material is different from the second adsorbent material.

7. The method of claim 1 , wherein the first adsorbent material is sensitive to steam.

8. The method of claim 1 , wherein the first adsorbent material is any one of CaO, Ca(OH) 2 , CaO—La 2 O 3 , and CaMg(CO 3 ) 2 .

9. A system for capturing emissions comprising:
a first swing adsorption reactor which receives a stream of recycled exhaust gas, wherein the first swing adsorption reactor comprises:
a first adsorbent material which adsorbs CO 2 ;
a first forward end from which a first N 2 stream is output wherein the first N 2 stream is an enriched N 2 stream;
a first blow down output feed which outputs a blow down stream to reduce the pressure in the first swing adsorption reactor;
a first purge input feed which receives a portion of the first N 2 stream;
a first purge output feed which outputs a first purge output comprising CO 2 and N 2 ;

a second swing adsorption reactor which receives the first purge output, wherein the second swing adsorption reactor comprises:
a second adsorbent material which adsorbs CO 2 ;
a second forward end from which a second N 2 stream is output;
a second blow down output feed which outputs a blow down stream to reduce the pressure in the second swing adsorption;
a second purge input feed which receives a steam purge; and
a second purge output feed which outputs a second purge output comprising CO 2 and steam.

10. The system of claim 9 , wherein the first blow down output feed reduces the pressure to an intermediate pressure value lower than a pressure value of the recycled exhaust gas and higher than a pressure value of the output from the second swing adsorption.

11. The system of claim 10 , wherein the intermediate pressure value is between 3 and 12 bar.

12. The system of claim 9 , wherein at least one of the first swing adsorption reactor and the second swing adsorption reactor comprises multiple adsorbent beds.

13. The system of claim 12 , wherein adsorption of CO 2 by the multiple adsorbent beds is cycled to allow regeneration of at least one bed without completely ceasing adsorption.

14. The system of claim 9 , wherein the first adsorbent material is different from the second adsorbent material.

15. The system of claim 9 , wherein the first adsorbent material is sensitive to steam.

16. The system of claim 9 , wherein the first adsorbent material is any one of CaO, Ca(OH) 2 , CaO—La 2 O 3 , and CaMg(CO 3 ) 2 .

Assignees

• Exxonmobil Res & Eng Co

Inventors

• Sundaram Narasimhan
• Thomann Hans
• Mittricker Franklin F
• STARCHER Loren

Classifications

• B01D2259/40028

  Depressurization · CPC title

• B01D2253/1124

  Metal oxides · CPC title

• B01D2259/40086

  by using a purge gas (B01D2259/4009 takes precedence) · CPC title

• B01D53/047 Primary

  Pressure swing adsorption · CPC title

• B01D2256/10

  Nitrogen · CPC title