Improved reactivity of large coal particles by K sub(2)CO sub(3) addition during steam gasification

In this study, the excess solution impregnation method was used to impregnate large coal particles (5 and 10 mm) with K sub(2)CO sub(3), and the effect of the additive on steam gasification reactivity was investigated. A washed bituminous, medium rank-C Highveld coal, with an ash content of 12.6 wt.% (air-dried basis), was used for experimentation. The excess solution method was used to impregnate coal particles with the selected additive, K sub(2)CO sub(3), and results from XRF analysis indicated that the potassium loading increased from 0.05 wt.% (raw coal) up to 0.83 wt.% (impregnated coal), on a coal basis. The potassium-impregnated large coal particles were used for low temperature (800-875 degree C) steam gasification experiments. Results obtained for the reactivity of the parent coal were compared to that of the impregnated coal, which indicated that the addition of K sub(2)CO sub(3) increased the reaction rate of large coal particles by up to 40%. It was also found that the addition of K sub(2)CO sub(3) decreased the activation energy, from 191 kj/mol (raw coal) to 179 kj/mol (impregnated coal).