Studies on the effect of different rates of heating on low temperature carbonisation assay of coals and their blends

摘要

The rate of heating on coal plays an important part in the conversion of coke from coal. With increasing heating rate than normal rate of heating in the laboratory, the plastic and coking properties of coal improves as it helps to form increase amount of plasticity, higher dilation and swelling, higher devolatilization resulting in increase yield of tar and decrease yield of coke. During lower rate of heating than normal, the formation of plastic mass becomes less and devolatilization of coal becomes slower showing very low fluidity, low plastic temperature range, dilation and swelling do not take place resulting inferior low temperature coke type. The increase yield of coke and decrease yield of tar is due to longer time coke-tar interaction in the primary stage carbonization in the lower heating rate. Higher rate of heating cannot improve the coking and plastic properties of very low rank, high volatile non coking to very weak caking coals. Very high rank coal deficient in coking and plastic properties in not appreciably improved its properties in higher rate of heating which is reflected in coke strength by laboratory micro tumbler test.