Distribution of alkaline (earth) metals and gasification reaction characteristics of HSQ coal under CO₂/H₂O atmosphere

The distributions of Hongshaquan coal's alkaline (earth) metals and their influence on coal char gasification reaction activity under different gasification conditions were investigated in a high-temperature gasification fixed-bed experimental system. The results showed that the Na discretely distributed on the char surface at low temperature, while it showed a slight aggregation phenomenon when the gasification temperature was higher than ash fusion temperature. During the gasification process, the K was evenly distributed on the char surface. The enrichment of Ca and Mg elements on the surface of coal char was relatively obvious. The migration clusters of calcium-containing and magnesium-containing minerals formed large-sized ash sphere in the depressions on the surface of coal char. There was a certain dependence on the distribution of the above two elements. As the carbon conversion increased, the apparent activation energy and pre-exponential factor all increased, and the reactivity of coal char became worse.