Integrated process for CO2 capture and use in thermal power production cycle

Patent metadata

Field	Value
Publication number	US-9598993-B2
Application number	US-201514744977-A
Country	US
Kind code	B2
Filing date	Jun 19, 2015
Priority date	Jun 19, 2015
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A process for reducing the amount of CO 2 released into the atmosphere with the exhaust gas stream produced by the combustion of a hydrocarbon fuel in an internal combustion engine (ICE) used to power a vehicle by capturing at least a portion of the CO 2 in a liquid sorbent on board the vehicle, recovering the CO 2 from the sorbent and compressing the CO 2 for temporary storage on board the vehicle, where the process is operated as a semi-closed system in which the liquid sorbent that captures the CO 2 serves as a working fluid and retains the CO 2 during the power generation cycle to produce mechanical energy or work, after which the CO 2 is desorbed for densification and recovery as an essentially pure gas stream and the working fluid is recycled for use in the process.

First claim

The invention claimed is:

1. A process for reducing the amount of CO 2 released into the atmosphere with the exhaust gas stream produced by the combustion of a hydrocarbon fuel in an internal combustion engine (ICE) used to power a vehicle by capturing at least a portion of the CO 2 with a sorbent on board the vehicle, recovering the CO 2 from the sorbent and compressing the CO 2 for temporary storage on board the vehicle, the process characterized by
a. passing the hot exhaust gas stream from the ICE through a plurality of heat exchangers in a first heat exchange zone to reduce the temperature of the exhaust gas stream to a value in a predetermined temperature range;
b. contacting the cooled exhaust gas stream in an absorption zone with a liquid CO 2 sorbent solution at a temperature within a predetermined temperature range, the solution comprising a liquid solvent in which is dissolved at least one compound that reversibly combines with CO 2 to capture at least a portion of the CO 2 from the exhaust gas stream to provide a CO 2 -rich solution;
c. separating the CO 2 -rich solution from the remaining exhaust gas stream that is of reduced CO 2 content;
d. discharging the remaining exhaust gas stream of reduced CO 2 content into the atmosphere;
e. pressurizing the CO 2 -rich solution and passing it into a boiler for passage in a first heat exchange relation with the exhaust gas stream to raise its temperature to desorb the CO 2 and provide a concentrated CO 2 -lean sorbent solution, and to vaporize a portion of the solvent from the sorbent solution to provide a vaporized solvent/CO 2 mixture;
f. separating the CO 2 -lean sorbent solution from the vaporized solvent/CO 2 mixture in a first separation zone;
g. passing the vaporized solvent/CO 2 mixture to a superheating zone where it passes in a second heat exchange relation with the hot exhaust gas stream directly from the ICE to further increase the temperature of the mixture;
h. passing the superheated solvent/CO 2 mixture to a turbine and expanding the mixture to a predetermined pressure value;
i. passing the hot expanded solvent/CO 2 mixture in heat exchange with the pressurized CO 2 -rich solution of step (e);
j. passing the solvent/CO 2 mixture to a condensing heat exchanger to lower its temperature to condense substantially all of the solvent vapor to the liquid state;
k. separating the condensed solvent from the CO 2 in a second separation zone and mixing all or a portion of the condensed solvent with the sorbent solution upstream of the absorption zone or discharging the solvent from the vehicle;
l. recovering the substantially pure CO 2 from the second separation zone and passing it to a compression zone to compress and densify the CO 2 and discharging any remaining water;
m. recovering the pressurized pure CO 2 and passing it to an on-board vessel for storage or for further processing to reduce its volume by changing its physical state;
n. passing the pressurized CO 2 -lean solution from the first separation zone in heat exchange relation to increase the temperature of the pressurized CO 2 -rich solution from the absorption zone;
o. introducing the pressurized CO 2 -lean solution into an expansion device to produce mechanical energy;
p. passing the reduced-pressure concentrated CO 2 -lean solution from the expansion device to a mixing device through which solvent is added to restore the desired concentration of the sorbent solution;
q. cooling the CO 2 -lean solution to the predetermined temperature range prior to passing it into the absorption zone; and
r. pressurizing the CO 2 -lean sorbent solution upstream of the absorption zone.

2. The process of claim 1 in which the solvent is water.

3. The process of claim 2 in which the increase in the temperature of the water/CO 2 mixture in step (g) is in the range of from 200° to 500° C.

4. The process of claim 1 in which the CO 2 -rich solution from the absorption zone is passed to the intake of a pump to increase its pressure to a predetermined system pressure.

5. The process of claim 1 in which the first heat exchange zone includes a final heat exchanger passing a cooling fluid at the predetermined temperature of the exhaust gas stream entering the absorption zone.

6. The process of claim 1 in which the mechanical energy output of the turbine and/or the expansion device is used directly to turn one or more pumps and/or one or more CO 2 compressors.

7. The process of claim 1 in which the mechanical energy output of the turbine and/or expansion device is used to generate electricity that is used to power pumps and or compressor motors and/or to charge a storage battery on board the vehicle.

8. The process of claim 1 in which the sorbent solution is prepared from one or more compounds selected from the group consisting of water, amine-functionalized molecules, alkali metal carbonates and bicarbonates, alkaline earth metal carbonates, alkali metal and alkaline earth metal oxides, aqueous ammonia and ammonium carbonate, alcohols, polyethers, amide compounds, molecular sieves, MOFs, COFs.

9. The process of claim 8 in which the polyether is a dimethylether of polyethylene glycol.

10. The process of claim 8 in which the CO 2 absorbing amide compound is N-methyl-2-pyrrolidone.

11. The process of claim 8 in which the solvent is methanol.

12. The process of claim 8 in which the CO 2 absorbing amine is monoethanolamine.

13. The process of claim 8 in which the CO 2 absorbing carbonate is potassium carbonate.

Assignees

• Saudi Arabian Oil Co

Inventors

• Younes Mourad Victor
• Al-Sadat Wajdi Issam
• Hamad Esam Zaki

Classifications

• B01D2252/204

  Amines · CPC title

• B01D2258/01

  Engine exhaust gases · CPC title

• B01D2252/2026

  Polyethylene glycol, ethers or esters thereof, e.g. Selexol · CPC title

• B01D2252/20484

  with one hydroxyl group · CPC title

• B01D53/1475 Primary

  Removing carbon dioxide · CPC title