Coking of coal is also called high temperature dry distillation of coal. A coal conversion process in which coal is used as raw material, heated to about 950℃ under the condition of air isolation, and then dry distilled at high temperature to produce coke, and at the same time, coal gas and coal tar are obtained, and other chemical products are recovered. In order to ensure the quality of coke, the most basic requirements for selecting coking coal are volatile, caking and coking; Most coking coals must be washed to ensure the lowest possible ash, sulfur and phosphorus content. When selecting coking coal, we must also pay attention to the expansion pressure of coal during coking. Coking with low volatile coal, because of its high colloid viscosity, is easy to produce high expansion pressure, which causes damage to coke oven masonry and needs to be solved by blending coal for coking.