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

Abstract

An experimental investigation has been carried out to study the bed temperature and gas concentration profiles due to combustion of an Indian coal in a laboratory-scale circulating fluidizedbed (CFB) combustor of 102 mm  102 mm cross-section and 5.25 m high, made of insulating firebricks. As the sulphur content of the coal burned was low, no sorbent was used. Sand acted as the bed material. The results are discussed for four different superficial 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 continues 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 NO x is also discussed, as it is a significant pollutant from coal combustion. The results are explained to obtain some insight into the combustion of coal in a CFB.