| 摘要 |
PURPOSE:To unnecessitate a large thermal decomposition furnace of an NH3 compound and to thermally decompose the NH3 compound efficiently by thermally decomposing the NH3 compound in a coal ash while said coal ash is transported through an ash treating pipe. CONSTITUTION:A waste gas of a coal burning boiler 1 is treated by a system consisted of a denitrification apparatus 2, an air preheater 3, a low temp. dust collector 4 and a desulfurization apparatus 6. In this case, the coal ash collected in the dust collector 4 containing the NH3 compound (e.g. ammonium sulfate) discharged from the dust collector 4 is thrown into the ash treating pipe 12 as well as a high temp. combustion waste gas of the boiler 1 is introduced into the pipe 12 and said ash and gas are subjected to solid-gas contact to thermally decompose the NH3 compound in the coal ash. In this case, the temp. in said pipe is 250-700 deg.C. Subsequently, the coal ash after thermal decomposition and the decomposed gas are separated in a solid-gas separator 13 and the decomposed gas is returned to a position in front of the denitrification apparatus 2 to be reutilized as a NH3 source. On the other hand, the coal ash is cooled in a cooler and, thereafter, transported to an ash treating installation 20. |
