Dust coal boiler, dust coal combustion method, dust coal fuel thermal power generation system, and waste gas purification system for dust coal boiler

摘要

A pulverized coal thermal power generation system that significantly reduces the amount of NOx emissions from a boiler and does not require a denitration unit is provided. When a denitration unit is not used, performance to remove mercury from a boiler waste gas is reduced. A waste gas purification system for a pulverized coal boiler, that compensates for this is provided.;A pulverized coal boiler having a furnace for burning pulverized coal, burners for supplying pulverized coal and air used for combustion into the furnace so as to burn the pulverized coal in an insufficient air state and after-air ports provided on the downstream side of the burners for supplying air used for perfect combustion characterized in that, an air ratio in the furnace is 1.05 to 1.14, and the residence time of a combustion gas from the burner disposed on the uppermost stage to a main after-air port is 1.1 to 3.3 seconds. Preferably, water is mixed in advance with the air supplied from the after-air port so as to increase the specific heat. Furthermore, pulverized coal carrying air in the burner and a part of air used for combustion are mixed together in advance before they are jetted into the furnace.;A waste gas purification system having a pulverized coal boiler, an air heater disposed downstream of the pulverized coal boiler for exchanging heat with a boiler waste gas to heat air used for combustion in the pulverized coal boiler, a dust removing unit, and a desulfurizing unit characterized in that, at least one of a halogen gas supply unit, a catalyst unit for oxidizing a mercury gas, and a mercury adsorbent blowing device is provided so as to oxidize mercury included in the waste gas.