A test study on influence of different coal sort

different load

and different air flow rate upon the bed temperature has been carried out on a 75 t/h circulating fluidized bed (CFB) boiler.The test shows that the bed temperature is gradually reduced along the height of furnace in case of lower volatile matter content in the coal sort

but the temperature of returned material is obviously en- hanced;the bed temperature is entirely increased in the event of increasing the load

but the temperature difference between bottom and centre of the furnace being decreased;the heat quantity carried out by the flue gas from dense-phase region is greater than that released from combustion while increasing the primary air flow rate

thus making the bed temperature to be lowered.