CCSEM study of ash forming reactions during lignite gasification

Ash particles in gasified lignite chars were analyzed by a computer-controlled scanning electron microscope (CCSEM). The reactions between mineral particles and the fate of dispersed inorganic species which are contained in the Beulah-Zap lignite are deduced on the basis of the CCSEM method. Interaction among discrete mineral particles was not significant during gasification below 800 °C. On the other hand, a large portion of the finely dispersed Na-species combined with inherent mineral particles like kaolinite and quartz, and the interaction was most significant with kaolinite under the same gasification conditions. Dispersed Ca-species was also combined with kaolinite and quartz, but the extent was much lower than with Na.