Temperature and gas concentration profiles in a circulating fluidized-bed combustor burning an Indian coal

An experimental investigation has been carried out to study the bed tempera ture and gas concentration profiles due to combustion of an Indian coal in a laboratory-scale circulating fluidized-bed (CFB) combustor of 102 mm x 10 2 mm cross-section and 5.25 m high, made of insulating firebricks. As the s ulphur content of the coal burned was low, no sorbent was used. Sand acted as the bed material. The results are discussed for four different superfici al velocities at a constant coal feed rate. The temperature of the bed was essentially uniform for each of the superficial velocities used. The oxygen concentration decreases along the riser height showing that combustion con tinues over its entire length. The carbon monoxide concentration decreases along the riser except only near the top. The carbon dioxide concentration, however, increases along the riser except near the top. The concentration of NOx is also discussed, as it is a significant pollutant from coal combus tion. The results are explained to obtain some insight into the combustion of coal in a CFB.