Abstract:
The experimental study on the Yangquan high-ash coal catalytic gasification with mixing-gas (air/steam) by using solid alkali (sodium hydroxide) or waste liquid of viscose fiber as the catalyst in a smallscale fluidized bed with 28mm i.d. was carried out. The loading saturation levels (LSL) of two catalysts in Yangquan high-ash coal are about 6%. Under the gasification temperature ranging from 830℃ to 900℃ and from 900℃ to 920℃, the apparent reaction order of Yangquan highash coal with respect to the unreacted carbon fraction approximates to 2/3 and 1/3 for the noncatalyst case, respectively. Also, the different values of apparent reaction order in the two temperature ranges are presented for the case with 3% solid alkali catalyst loaded. At the low temperature ranging from 830℃ to 860℃, the apparent reaction order of catalytic gasification is 1 since enough active carbon sites on the coal surface are formed during the catalytic gasification by solid alkali. But at the high temperature ranging from 860℃ to 920℃, the sodium carbonate produced by the reaction of solid alkali with carbon dioxide can be easily fused, transferred and redistributed, which affects the gasification reaction rate, and the apparent reaction order of catalytic gasification is reduced to 1/3.