Effects of Potassium Additive on Transformation of Sulphur in Coal During Pyrolysis

Three coals of different rank with rich organic sulphur were chosen as the experimental samples. Effects of addition of KCl into coal on sulphur transfer and release were studied in the fixed bed pyrolysis-gas chromatographic analysis apparatus. The results show that KCl in coals obviously affects the releasing temperature of sulphur and its ratio in gas and char. The role of KCl in coal mainly presents to promote the release of sulphur in Shuiyu coal to gas and slightly inhibits the formation of sulphur-containing gases in Zunyi coal. For Ximeng coal, it is more obvious to promote the formation of COS than H2S. The sulphur contents in chars from pyrolysis of three coals at 1000 degrees C are 39.8, 67.39 and 62.08 %, while they change respectively to 29.24, 64.04 and 53.95 % for coals containing KCl, showing that the sulphur-containing groups in the coal with high organic sulphur are more easily transformed to other forms by KCl additive.