Methods and systems for reducing carbon dioxide in combustion flue gases
View Patent ↗A method for processing flue-gas, in an exemplary embodiment, includes providing an absorber unit having a membrane contactor, channeling a combustion flue gas along a first surface of the membrane contactor, and channeling an ammonia-based liquid reagent along a second opposing surface of the membrane contactor. The method also includes partially separating the ammonia-based liquid from the flue gas such that the ammonia-based liquid and the flue gas contact at gas-liquid interface areas, defined by a plurality of pores of the membrane contactor, to separate CO 2 from the flue gas by a chemical absorption of CO 2 within the ammonia-based liquid to produce a CO 2 -rich ammonia-based liquid.
1. A method for processing flue-gas that contains carbon dioxide (CO 2 ), said method comprising:
providing an absorber unit having a membrane contactor that has a surface area of about 10 to about 100 m 2 /gr and a void volume of about 90% to about 95%;
channeling a combustion flue gas along a first surface of the membrane contactor;
channeling an ammonia-based liquid reagent along a second opposing surface of the membrane contactor;
coupling a desorber unit in flow communication with the absorber unit to receive carbon dioxide (CO 2 )-laden ammonia-based liquid reagent from the absorber unit; and
channeling lean ammonia-based liquid reagent discharged from the desorber unit through a steam generator coupled in flow communication between the desorber unit and the absorber unit.
2. A method in accordance with claim 1 further comprising coupling a desorber unit to the absorber unit.
3. A method in accordance with claim 2 further comprising channeling the CO 2 -rich ammonia-based liquid to the desorber unit.
4. A method in accordance with claim 3 further comprising heating the CO 2 -rich ammonia-based liquid to release CO 2 from the CO 2 -rich ammonia-based liquid.
5. A method in accordance with claim 1 wherein providing an absorber unit having a membrane contactor comprises providing an absorber unit having a hydrophobic membrane contactor.
6. A method in accordance with claim 1 wherein providing an absorber unit having a membrane contactor comprises providing an absorber unit having an expanded polytetrafluoroethylene membrane contactor.
7. A combustion system comprising:
an absorber unit comprising:
a housing for channeling a combustion flue gas that contains carbon dioxide (CO 2 );
an ammonia-based liquid reagent channeled within said housing;
a membrane contactor positioned within said housing, wherein said membrane contactor comprises a first surface, a second opposing surface, and a plurality of pores defining gas-liquid interface areas and having a surface area of about 10 to about 100 m 2 /gr and a void volume of about 90% to about 95%, the combustion flue gas is channeled along said first surface and said ammonia-based liquid reagent is channeled along said second opposing surface; and
a desorber unit coupled to said absorber unit, wherein said desorber unit receives and releases CO 2 from the CO 2 -rich ammonia-based liquid; and
a steam generator coupled between said desorber unit and said absorber unit, such that lean ammonia-based liquid reagent discharged from the desorber unit is channeled through said steam generator prior to entering said absorber unit.
8. A combustion system in accordance with claim 7 wherein said membrane contactor comprises a hydrophobic material.
9. A combustion system in accordance with claim 7 wherein said membrane contactor comprises an expanded polytetrafluoroethylene material.
10. A combustion system in accordance with claim 7 wherein said membrane contactor comprises a plurality of hollow fibers.
11. A combustion system in accordance with claim 10 wherein said plurality of hollow fibers is packaged in a tube-and-shell arrangement.
12. A combustion system in accordance with claim 7 wherein said membrane contactor comprises a substantially planar sheet.
13. A combustion system in accordance with claim 12 wherein said substantially planar sheet is packaged as a spiral-wound module.
14. A flue-gas processing system comprising:
a housing for channeling a combustion flue gas that contains carbon dioxide (CO 2 );
an ammonia-based liquid reagent channeled within said housing; and
a membrane contactor positioned within said housing, wherein said membrane contactor comprises a first surface, a second opposing surface, and a plurality of pores defining gas-liquid interface areas, said membrane contactor having a surface area of about 10 to about 100 m 2 /gr and a void volume of about 90% to about 95%, the combustion flue gas is channeled along said first surface and said ammonia-based liquid reagent is channeled along said second opposing surface;
a desorber unit coupled to said housing for receiving carbon dioxide (CO2)-laden ammonia-based liquid reagent from said housing; and
a steam generator coupled in flow communication with said desorber unit, for receiving a lean ammonia-based liquid reagent discharged from said desorber unit and for channeling the lean ammonia-based liquid reagent to said housing.
15. A flue-gas processing system in accordance with claim 14 wherein said membrane contactor comprises a hydrophobic material.
16. A flue-gas processing system in accordance with claim 14 wherein said membrane contactor comprises an expanded polytetrafluoroethylene material.
17. A flue-gas processing system in accordance with claim 14 wherein said membrane contactor comprises a plurality of hollow fibers.
18. A flue-gas processing system in accordance with claim 17 wherein said plurality of hollow fibers is packaged in a tube-and-shell arrangement.
19. A flue-gas processing system in accordance with claim 14 wherein said membrane contactor comprises a substantially planar sheet.
20. A flue-gas processing system in accordance with claim 19 wherein said substantially planar sheet is packaged as a spiral-wound module.