REVERSIBLE SOLID ADSORPTION METHOD AND SYSTEM UTILIZING WASTE HEAT FOR ON-BOARD RECOVERY AND STORAGE OF CO2 FROM MOTOR VEHICLE INTERNAL COMBUSTION ENGINE EXHAUST GASES

• US 20130298532A1
• Filed: 01/20/2012
• Published: 11/14/2013
• Est. Priority Date: 01/20/2011
• Status: Active Grant

• Current Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Original Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Inventors: Hamad, Esam Zaki, Al-Sadat, Wajdi Issam
• Granted Patent: US 9,581,062 B2
• Time in Patent Office: Days
• US Class Current: 60/274
• CPC Class Codes: B01D 2251/304 of sodium
• CPC Class Codes: B01D 2251/402 of magnesium
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2259/65 Employing advanced heat integration, e.g. Pinch technology
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/92 of engine exhaust gases exhaust or silencing apparatus for internal combustion engines, machines or engines in general, having means for purifying, rendering innocuous or otherwise treating exhaust gases F01N3/00
• CPC Class Codes: F01N 3/00 Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust electric control F01N9/00; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00 ; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Abstract

A method and system are described for on-board treatment of an exhaust stream containing CO₂ emitted by a hydrocarbon-fueled internal combustion engine (ICE) used to power a vehicle in order to reduce the amount of CO₂ discharged into the atmosphere which include:

• • a. a treatment zone on board the vehicle containing a capture agent having a predetermined capacity for extracting CO₂ from the exhaust stream,
    • the treatment zone preferably operating in swing mode with at least two subsystems, each having an inlet for admitting the exhaust gas stream and an outlet for passage of a treated exhaust stream having a reduced CO₂ content,
    • the treatment zone preferably operating in swing mode with at least two subsystems, each including a heat exchanger with an inlet for receiving the hot exhaust gas stream from the ICE for passage in heat exchange relation with the capture agent to release CO₂ and regenerate the capture agent, and an outlet for the cooled exhaust gas stream,
    • the treatment zone having a CO₂ discharge outlet for CO₂ released from the regenerated capture agent;
  • b. a compression zone in fluid communication with the CO₂ discharge outlet from the treatment zone, the compression zone including one or more compressors for reducing the volume of the CO₂;
  • c. a storage zone for receiving the compressed CO₂ for temporary storage on board the vehicle; and
  • d. an exhaust gas conduit in fluid communication with the treated exhaust gas stream outlet from the treatment zone.

Claims

1. A method for reducing the amount of CO₂ discharged into the atmosphere with the exhaust gas stream emitted by an internal combustion engine (ICE) used to power a vehicle, the method comprising:

a. passing the exhaust gas stream into contact with a CO₂ capture agent on board the vehicle, the capture agent having a predetermined capacity to extract CO₂ from the exhaust stream;

b. discharging a treated exhaust gas stream having a reduced CO₂ content into the atmosphere;

c. discontinuing the passage of the exhaust gas stream in contact with the capture agent when the concentration of the CO₂ extracted by the capture agent has reached a predetermined level;

d. heating the CO₂ capture agent to release the extracted CO₂ and regenerate the capture agent;

e. recovering an essentially pure CO₂ gas stream;

f. recovering heat and energy from the hot exhaust gas stream emitted by the ICE by contact with an energy conversion medium;

g. compressing the recovered CO₂ gas on board the vehicle to reduce its volume using the energy recovered in step (f); and

h. temporarily storing the compressed CO₂ on board the vehicle.

2. The method of claim 1 which operates substantially continuously following start-up of the vehicle'"'"'s ICE.

3. The method of claim 1 which further includes measuring the CO₂ level remaining in the treated exhaust gas stream and comparing the value of the measured level to a predetermined limiting value.

4. The method of claim 3 where the limiting value corresponds to the predetermined capacity of the CO₂ capture agent and the passage of the exhaust gas stream in contact with the CO₂ capture agent is discontinued when the limiting value is reached.

5. The method of claim 1 in which the CO₂ capture agent is heated in step (d) by heat exchange with the hot exhaust gas stream.

6. The method of claim 5 in which the heat exchange occurs in a tube and shell heat exchanger.

7. The method of claim 1 in which the CO₂ capture agent is a high temperature solid adsorbent selected from the group consisting of chemical adsorbents and physical adsorbents.

8. The method of claim 1 in which the CO₂ capture agent is selected from solid adsorbents and liquid adsorbents on a solid carrier.

9. The method of claim 1 in which the CO₂ capture agent is a solid adsorbent that is contacted with the exhaust gas stream in a fixed bed or a fluidized bed.

10. The method of claim 1 in which a portion of the heat energy of the exhaust stream is utilized in the regeneration step (d) and compression of step (g).

11. The method of claim 1 in which the CO₂ content of exhaust gas stream is reduced by at least 10%.

12. The method of claim 1 in which the capture agent is maintained in two separate swing zones and the exhaust gas is passed through one of the zones while the other zone is heated to release CO₂ and regenerate the capture agent.

13. The method of claim 1 in which the hot exhaust from the vehicle'"'"'s engine is passed in heat exchange relation in step (d) to regenerate the capture agent.

14. The method of claim 1 in which the passage of the exhaust gas stream in contact with the capture agent in step (c) is discontinued when the temperature or rate of increase of the temperature of the capture agent reaches a predetermined value.

15. The method of claim 14 in which the temperature is measured by a plurality of temperature sensors in contact with the capture agent.

16. The method of claim 1 in which the passage of the exhaust gas stream in contact with the capture agent in step (c) is discontinued when the pressure or, the rate of increase of the pressure in a vessel containing the capture agent during its heating in step (d) reaches a predetermined value.

20. The system of claim 16 in which the diverter valve is controlled based on the operating conditions of the ICE.

17. A system for on-hoard treatment of an exhaust gas stream containing CO₂ emitted by a hydrocarbon-fueled internal combustion engine (ICE) used to power a vehicle in order to reduce the amount of CO₂ discharged into the atmosphere, the system comprising:

a. a treatment zone on board the vehicle containing a capture agent having a predetermined capacity for extracting CO₂ from the exhaust stream,

the treatment zone having an inlet for admitting the exhaust gas stream and an outlet for passage of a treated exhaust stream having a reduced CO₂ content,

the treatment zone further including a heat exchanger with an inlet for receiving the hot exhaust gas stream from the ICE for passage in heat exchange relation with the capture agent to release CO₂ and regenerate the capture agent, and an outlet for the cooled exhaust gas stream,

the treatment zone having a CO₂ discharge outlet for CO₂ released from the regenerated capture agent;

b. a compression zone in fluid communication with the CO₂ discharge outlet from the treatment zone, the compression zone including one or more compressors for reducing the volume of the CO₂;

c. a storage zone for receiving the compressed CO₂ for temporary storage on board the vehicle; and

d. an exhaust gas conduit in fluid communication with the treated exhaust gas stream outlet from the treatment zone.

18. The system of claim 17 in which the treatment system is comprised of at least two parallel subsystems configured and constructed to operate in swing mode, with valves to direct the vehicle'"'"'s exhaust to one and then another of the at least two subsystems for extraction of CO₂ and simultaneously regenerate the capture agent in another of the at least two subsystems, whereby the system is operable continuously to treat the engine exhaust stream.

19. The system of claim 17 which includes a diverter valve for regulating the volumetric amount of the exhaust gas stream which passes into the treatment zone before being discharged into the atmosphere.

21. The system of claim 17 which includes control means for discharging all or a portion of the exhaust gas stream into the atmosphere without passing through the treatment zone.