Gasification of bituminous coal with K-exchanged brown coal prepared from potassium chloride

Abstract

A new method utilizing KCl as a catalyst precursor in the gasification of high rank coal was investigated. Potassium-loaded brown coal (Yallourn coal) prepared with KCl using an ion-exchange technique was physically mixed with a higher rank coal (Liddell coal). The mixture was gasified in steam (0.03 MPa) or carbon dioxide (0.1 MPa) with a thermobalance. The gasification temperature ranged from 873 to 973 K. Incorporation of potassium catalyst into Yallourn coal significantly enhanced the reactivity not only of Yallourn char but also of Liddell char. The effectiveness of the catalyst on the gasification of Liddell coal was dependent on coal particle size and the mixing ratio of K-exchanged Yallourn coal to Liddell coal. Electron probe microanalysis showed that potassium catalyst transferred from Yallourn char to Liddell char and spread out over the Liddell char surface in the gasification stage. The remarkable rate enhancement of high rank coal char by this technique was observed in both steam and carbon dioxide gasification.