EXHAUST GAS TREATMENT APPARATUS

PROBLEM TO BE SOLVED: To obtain an exhaust gas treatment apparatus suitable for reducing SO3 in exhaust gas. SOLUTION: In an exhaust gas treatment apparatus, an NH3 injection device for removing SO3 is arranged only to the exhaust gas flow passage provided to the inlet of a denitration device and a washing device 17 is provided to the GGH heat recovery device 7 arranged to the exhaust gas flow passage provided to the inlet of a dust collector and a high performance demister 16 is provided to the outlet part of an absorbing tower 22. Since NH3 is not injected in the dust collector, no ammonium sulfate is generated and the concn. of soot flowing in th absorbing tower 22 of a desulfurization equipment is not increased and SO3 is condensed in the GGH heat recovery device 7 but can be easily removed by the washing device and SO3 mist contained in exhaust gas is also removed by the high performance demister 16 provided to the outlet of the absorbing tower of the desulfurization equipment and the SO3 mist recovered in the absorbing tower 22 can be recovered as gypsum in the absorbing tower 22 of the desulfurization equipment by the reaction with limestone and, therefore, the concn. of soot at the outlet of the desulfurization equipment is not increased and the concn. of NH3 in waste water is not also increased.