EFFECT OF CALCIUM AND CALCIUM MINERALS IN COAL ON ITS THERMAL-ANALYSIS

The effect of the presence of limestone and dolomite in coal, and calc ium in lignite, on atmospheric-pressure temperature-programmed reducti on (AP-TPR) analysis was studied. AP-TPR experiments were carried out on a bituminous coal with added limestone and dolomite and on a demine ralized lignite. The results showed that both calcium minerals capture d the gaseous H2S formed under AP-TPR conditions and produced CaS. Con sequently the sulfur recovery monitored was too low and the AP-TPR kin etograms were deformed. The study also showed that the influence of do lomite is greater than of limestone. AP-TPR analysis of lignite demine ralized and then loaded with calcium ions again showed a clear lowerin g of sulfur comparable with that of dolomite, but starting at a higher temperature. Copyright (C) 1997 Elsevier Science Ltd.