摘要 |
Pyrolyzing pulverized coal to form char and volatiles, separating the char from the volatiles, burning the char in heat-transfer relationship with a stoichiometric excess of air, forming thereby ash and a mixture of gases, the excess of air being chosen to produce in the ash a temperature below the fusion temperature thereof, separating the mixture of gases from the ash, and thereafter burning the volatiles in the mixture of gases. Also, coal burning apparatus which comprises, in combination a spouted bed pyrolyzer, a fluidized bed combustor, a first cyclone, a second cyclone, and an afterburner, the pyrolyzer being connected to accept pulverized coal and to discharge char to the combustor and gaseous materials with entrained particulate material to the first cyclone, the first cyclone being connected to deliver gases to the afterburner, the combustor being connected to accept also a combustion supporting gas and to deliver to the second cyclone gaseous materials with entrained particulate material, and the second cyclone being connected to deliver gaseous material to the afterburner. |