CARBON DIOXIDE ABSORPTION METHOD FROM MIXED GAS BY AMMONIA LIQUOR

摘要

A method for absorbing carbon dioxide by using ammonia water is provided to increase carbon dioxide absorption efficiency of the absorption liquid by extracting a portion of an absorption liquid with a high temperature from an inner part of an absorption tower to an outer part of the absorption tower, cooling the absorption liquid, and supplying the cooled absorption liquid into the absorption tower, thereby lowering temperature of the absorption liquid. As a method for contacting carbon dioxide contained in flue gas with ammonia water in an absorption tower(10) to absorb and remove carbon dioxide, a method for absorbing carbon dioxide by using ammonia water comprises the steps of: recovering ammonia water with a high temperature at a preset position of the absorption tower; cooling the recovered ammonia water with a high temperature to a preset temperature; and supplying the cooled ammonia water into the absorption tower again. The ammonia water has a concentration of 1 to 4 wt.%. The ammonia water with a high temperature is recovered in the amount corresponding to 1/6 to 1/3 of an amount of the ammonia water supplied into the absorption tower. The recovered ammonia water with a high temperature is cooled to a temperature of 20 to 30 deg.C before the cooled ammonia water is supplied into the absorption tower again. The cooled ammonia water is supplied again into a position of the absorption tower that is the same as or higher than that of the absorption tower from which the ammonia water with a high temperature is recovered.