Patent ID: 9675932
Date: 2017-06-13
CPC Classifications: B01D

Claim:
1. An impurity removal system having a plurality of impurity separators comprising a plurality of compressors configured to stepwisely compress an oxyfuel combustor exhaust gas mainly constituted of carbon dioxide to a target pressure for liquefied or compressed transportation, and coolers each for cooling the exhaust gas from the corresponding compressor to discharge water condensed by the cooling as drain, an alkaline aqueous solution being supplied to an exhaust gas entry side of one of the coolers to discharge impurities in the exhaust gas together with the drain, the system comprising a drain tank for receiving the drain from at least one of the coolers to store a predetermined amount of drain, an alkaline aqueous solution supply unit comprising an aqueous solution adjustment tank for receiving and storing part of the drain from the drain tank, a solid alkaline agent supplier for supplying a solid alkaline agent to the drain in the aqueous solution adjustment tank to produce the alkaline aqueous solution, an alkaline concentration controller for controlling the solid alkaline agent supplier to regulate a detected alkaline concentration of the alkaline aqueous solution and a pump for supplying the alkaline aqueous solution in the aqueous solution adjustment tank to the exhaust gas entry side of the cooler, and an alkaline supply control unit comprising an impurity sensor arranged downstream of the cooler in a succeeding one of the impurity separators, a drain pH sensor for obtaining a detected pH of the drain in the drain tank, and a supply controller to which a detected impurity value from the impurity sensor and a detected pH from the drain pH sensor are inputted, the supply controller for regulating the alkaline aqueous solution supply unit on a basis of the detected impurity value by the impurity sensor so as to keep the detected pH by the drain pH sensor to a set value, thereby controlling an alkaline supply amount to the exhaust gas entry side of the cooler.