Effects of blending ratios of coals in blends on the steam-gasification characteristics of coke

The coal blends with the different ratios of three dif-ferent ranks of coals were used for the preparation of the coke at 1 150 ℃ in a muffle furnace. The gasification reactivity,gas production and the composition of product gas were tested through a fixed-bed reactor in a laboratory scale coupled with the gas analyzer. It shows that the gasifica- tion reactivity and product gas composition are con-trolled by the coal blending ratios in the blends. The order that the increasing effect of single coal on the CRI of the cokes is:MSC>WGC>DFC. The relative change of the subbituminous coal and fat coal in blends has the crucial influence on the pore structure and the reactivity of the coke. The blending ratio of the coals in blends affects the content of the catalytic element in the coke. The increase of the gas coal and fat coal lead to the increase of the catalytic element in the coke,and the ratio of fat coal being about 0. 3 is especially helpful for the retaining of the catalytic element. The component of volatiles and the evolution of the pore structure during pyrolysis influence the content of catalytic element in the coke. The catalytic elements in the coke can promote the occurrence of the water-gas shift reaction and then adjust the composition of product gas. The results provide a theoreti- cal foundation for improving the coke reactivity and modifying the composition of the product gas through the optimiza- tion of coal blending in the coking process,thus contributing to the utilization of excess coking capacity and low quality coking coal.