Experimental study on gasification characteristics and slagging behavior of Chinese typical high ash fusion temperature coal in lab scale downflow gasifier

Abstract

In order to extend the applicability of entrained flow gasification technology by using Chinese high ash fusion temperature (AFT) coal with dry ash extraction, gasification characteristics and slagging behavior of Chinese high AFT coal were studied in a lab scale downflow gasifier. The results showed that under this experimental condition, the optimum temperature window which is suitable for dry ash extraction with high AFT coal ranges from 1573 to 1623 K, as well as the corresponding optimum O2/coal mass ratio ranges from 0.93 to 1.13. The cold gas efficiency and carbon conversion are around 42 and 90%, respectively in this experiment. The slag on the bottom of the gasifier and in the cyclone existed, on the whole, as solid except that some small parts were melted with several micrometers in diameter, while the slag in the bag filter had remained unmelted when continue operating at an optimum condition for 1.5 h. Due to the small percentage of melted parts in the slag, the tendency of plugging is small and the problems of plugging can be avoided at the exit of gasifier by gasifying Chinese high AFT coal at around 1623 K. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.