Catalytic Steam Gasification Reactivity of HyperCoals Produced from Different Rank of Coals at 600-775 °C

HyperCoal is a clean coal with ash content <0.05 wt %. HyperCoals were prepared from a brown coal, a sub-bituminous coal, and a bituminous raw coal by solvent extraction method. Catalytic steam gasification of these HyperCoals was carried out with K2CO3 at 775, 700, 650, and 600 degrees C, and their rates were compared. HyperCoals produced from low-rank coals were more reactive than those produced from the high-rank coals. XRD measurements were carried out to understand the difference in gasification reactivity of HyperCoals. Arrhenius plot of 1n (k) vs 1/T in the temperature range 600-825 degrees C was a curve rather than a straight line. The point of change was observed at 700 degrees C for HyperCoals from low-rank coals and at 775 degrees C for HyperCoals from high-rank coals. Using HyperCoal produced from low-rank coals as feedstock, steam gasification of coal may be possible at temperatures less than 650 degrees C.