| 摘要 |
PURPOSE:To ecomonically treat NH3-contg. fly ashes by heating the NH3-contg. fly ashes to allow NH3 to decompose and evaporate, utilizing this for removal of NOX and recovering the heat of the fly ashes by air for combustion. CONSTITUTION:In a denitration reactor 4 provided on the lower stream side of the economizer 2 of a coal firing boiler 1, NH3 is injected from a nozzle 3. A small amount of unreacted NH3 reacts with the SO3 in the gas and is bound or adsorbed by the fly ashes. The NH3-contg. fly ashes collected in a dust collector 6 are introduced via a cyclone 11 into an NH3 removing heater 15, where the NH3 content is thermally decomposed and evaporated by a combustion gas. The gas is then flowed through a line 24 into the upper stream side of the reactor 4. The high-temp. fly ashes removed of NH3 are introduced into a heat recovery cooler 27, where heat is recovered therefrom by the combustion air taken out from the outlet of steam air heater 7. The air of elevated temp. is returned to the combustion air lower stream side of the outlet of the air heater 5. |
