NOX CONTROL METHOD IN STEP INCINERATOR

PURPOSE:To enable a stabilized and high incineration of materials containing moistures as well as a decrease of production of NOx by dividing feed of the air for combustion into two system such as blowing from the lower part of the fire bed and blowing into a gas phase in the upper part of the fire bed. CONSTITUTION:Dehydrating cake is drawn out from a hopper 1 to a dry fire bed 3 by a pusher 2, heated and dried by circulation gas G in high temperature and combustion gas S in low temperature which are heated by a heater 13 on the fire bed 3, and transferred to the combustion fire bed successively. The cake bed reaching a fired bed 4 is successively incinerated on the fire bed by getting feed of combustion gases A, B respectively from both fire bed for combustion and a header 19 for blowing of the air. The incineration residues which are semi-molten is exhausted from an outlet 10 for slag. This air A performs cooling function of the fire bed and is limited in its amount and temperature enough to burn the fixed carbon content in the cake bed to control production amount of NOx. Moreover, the air B is mainly blown as the one for combustion of inflammable gas existing on the gas phase within the furnace.