METHOD AND DEVICE FOR RECOVERING CO2

摘要

PURPOSE:To cool waste combustion gas approximately at ordinary pressure in this method utilizing the cold of LNG by using a gas having a lower solidifying temp. than CO2 as the low-temp. gas to be mixed into the waste gas. CONSTITUTION:The waste combustion gas from a boiler 1 is introduced into a dehumidifier 2 and dehumidified to the humidity region where ice is not deposited on a heating surface, and the waste gas contg. remaining moisture and CO2 is introduced into a dry ice crystallizer 3 as a mixing tank. The waste gas is heat-exchanged with the cold LNG introduced through a low-temp. circulating gas pipeline 4, and the obtained low-temp. recirculating dry gas is supplied to the mixing tank 3 and directly mixed with the waste gas to form dry ice. The dry ice is introduced into a cyclone 5 and separated, and the circulating gas (consisting essentially of N2 and O2) is sent to a heat exchanger 6. Since the low-temp. circulating gas has a lower solidifying temp. than CO2, the gas is directly mixed with the waste gas.