| 摘要 |
PURPOSE:To remove the adhered substance on a preheater, by passing a part of exhaust gas through a first regeneration type air preheater through a denitration apparatus to heat secondary air and passing the remainder of the exhaust gas through a second regeneration type air preheater and bypassing secondary air to send the same to a boiler. CONSTITUTION:The exhaust gas 2 issued from a coal firing boiler 1 is divided into two systems and a part of the exhaust gas is mixed with NH3 from an ammonia injection nozzle 3 to perform denitration in a denitration apparatus 4 and guided to an electric precipitator 7 through a first regeneration type air preheater 20 while the remainder of the exhaust gas is directly guided to the electric precipitator 7 through a second regeneration type air preheater 21. When the adhered substance of the first preheater 20 is removed, a damper B is opened to allow secondary air 6b to bypass the first preheater 20 and said air 6b is heated only by a steam type air preheater 12 to be supplied to the boiler 1 while primary water 6a is heated by the second preheater 21. Whereupon, the temp. of the first preheater 20 rises and acidic ammonium sulfate is decomposed and the adhered substance is removed without stopping the operation of the boiler. |
