Flue gas desulfurization device, combustion system and combustion method

摘要

Disclosed is a desulfurization device that releases exhaust gas from the desulfurization device into the atmosphere without reduction in CO recovery rate and without mercury components, and a combustion system that uses said desulfurization device. Because the absorbent (6) of the desulfurization device is drawn from an absorbent reservoir (11) by a circulating pump (5) and sprayed through spray nozzles (4) into a desulfurization-absorption unit (26) and, in the absorbent reservoir (11), is mainly circulated outside the wall of a water seal tube (7) by a stirrer (10), the flow of the absorbent (6) that falls from the desulfurization-absorption unit (26) into the water seal tube (7) flows in a single direction from top to bottom and hinders the ascension of gas bubbles. Intermixing of the gas (27) for oxidizing the sulfur dioxide, which is generated in the absorbent, with the desulfurization device exhaust gas (2) is thereby prevented, efficient CO recovery is possible without reduction in the CO concentration recovered from the exhaust gas after desulfurization by the CO recovery device (17) and mercury in the combustion exhaust gas is absorbed in the absorbent of the desulfurization device (3) and is not released directly into the atmosphere.