| 摘要 |
<p>PURPOSE:To contrive to save energy as well as to carry out stable coal burning waste gas treatment by a method wherein an NH3 compound in a coal ash is thermally decomposed by a high temp. combustion gas in the system and a decomposed gas is reutilized as an NH3 source of a denitrification apparatus. CONSTITUTION:A waste gas of a coal burning boiler 1 is treated by a system consisted of a denitrification apparatus 2, an air preheating apparatus 3, a low temp. dust collecting apparatus 4 and a desulfurization apparatus 6. In this case, a coal ash containing the NH3 compound discharged from the dust collecting apparatus is thrown into a thermal decomposition furnace 13 through an ash hopper 12 and said NH3 compound is thermally decomposed at a temp. of 250-700 deg.C by a high temp. combustion gas of the boiler 1. Then, the coal ash after the thermal decomposition and the decomposed gas are separated in a solid-gas separator 15 and the decomposed gas is returned to a position in front of the denitrification apparatus 2 to be reutilized as an NH3 source. On the other hand, the coal ash is cooled by air in a cooler 18 and, thereafter, transported to an ash treating installation 21. Further, air heated to about 200-500 deg.C after heat exchanged with the high temp. coal ash in the cooler 18 is blown into a coal ash transport pipe 11 of an upstream side of the furnace 13 and used as a source for transporting the NH3 containing coal ash.</p> |
