| 摘要 |
PURPOSE:To contrive to reduce the amount of NOx discharged from a space heater and to improve the combustion efficiency of the heater by a method wherein a honeycomb- shaped semiconducting ceramic heater (PTC heater) with positive resistance-temperature coefficient, on the surface of which metallic catalyser is carried, is used in combination with a honeycom catalyser for catalytic combustion purpose. CONSTITUTION:Fuel mixed with combustion air 4 is supplied to an inlet 7 in the upstream part of a honeycomb-shaped PTC heater catalyser 1 and to dampers 6 arranged between said honeycomb-shaped PTC heater catalyser 1 and a honeycomb catalyser 2. Combustion gas 8 from the honeycomb catalyser 2 is heat-exchanged with the combustion air 4 by means of a heat exchanger 5. At the start of a heater, the dampers 6 are closed and fuel-air mixture is supplied through the inlet 7 to the honeycomb-shaped PTC heater catalyser 1 in order to perform catalytic combustion. With the lapse of time, the temperature of the combustion air 4 is raised by the combustion gas 8 up to the temperature, at which the honeycomb catalyser 2 starts its catalytic combustion. At this time, the dampers 6 are open so as to supply the major part of the fuel-air mixture between the honeycomb-shaped PTC heater catalyser 1 and the honeycomb catalyser 2 in order to perform the most part of combustion at the honeycomb catalyser 2. |
