FINELY DISPERSED CALCIUM IN HARD AND BROWN COALS - ITS INFLUENCE ON PRESSURE AND BURN-OFF DEPENDENCIES OF STEAM AND CARBON-DIOXIDE GASIFICATION

As known Calcium can act as a catalyst in steam and carbon dioxide gasification as far as it is finely dispersed throughout the particle and not bound in minerals. Former works demonstrate, however, that the compounds of calcium are not as mobile as K-compounds. In contrast they deactivate with increasing burn-off by cluster formation. To what extent the catalysis by Ca, i.e. its burn-off dependence or its deactivation, is influenced by the temperature and pressure conditions of gasification was the subject of the present paper. Besides, the Ca-compounds formed during deactivation in steam and carbon dioxide are identified. © 1990.