The effect of coal rank and carbonization temperature on SO2 adsorption properties of coal chars

Coals of different rank were used to study the effect of coal type and carbonization temperature on SO2 adsorption by chars. The best adsorption properties were shown by chars obtained at a temperature of 700 degrees C from lower-rank coals. The maximum adsorption of SO2 at room temperature was 130 mg g(-1). Adsorbed SO2 underwent 70-90% desorption from the chars obtained from lower-rank coals and only 40-75% from the chars of higher-rank coals in the temperature range up to 500 degrees C. Thermal analysis of the chars showed that the desorption is a two-step process: the first from 200 to 350 degrees C in which the greater part of the SO2 is desorbed, and the second from 350 to 500 degrees C. (C) 1997 Elsevier Science Ltd.