Carbon dioxide capture from power or process plant gases

摘要

The present invention are methods for removing preselected substances from a mixed flue gas stream characterized by cooling said mixed flue gas by direct contact with a quench liquid to condense at least one preselected substance and form a cooled flue gas without substantial ice formation on a heat exchanger. After cooling additional process methods utilizing a cryogenic approach and physical concentration and separation or pressurization and sorbent capture may be utilized to selectively remove these materials from the mixed flue gas resulting in a clean flue gas.

主权项

1. A method for removing a preselected substance from a flue gas stream comprising:
cooling the flue gas stream by direct contact with a cool liquid to remove water from the flue gas stream; compressing the flue gas stream to approximately 120 psia to remove additional water; dehydrating the compressed flue gas stream with either a first absorbent or a first adsorbent; cooling the compressed, dehydrated flue gas stream by indirect heat exchange with cold expanded flue gas components; contacting the compressed, dehydrated flue gas stream with a second absorbent or a second adsorbent to physically absorb or adsorb the preselected substance; regenerating the second absorbent or the second adsorbent, thereby releasing the preselected substance from the second absorbent or the second adsorbent into a separate stream; and expanding the compressed, dehydrated, treated flue gas stream through a gas expander, thus producing electric power, and cooling the expanded stream which is reheated by indirect heat exchange with the compressed, dehydrated flue gas stream.