When measuring the volatile matter of coal, the remaining non-volatile substances are called coke residue, and the coke residue minus the ash content is called fixed carbon. It is a non-volatile solid combustible material in coal, which can be calculated using (100-M-A-V) and is a mixture of high molecular weight compounds. The higher the fixed carbon content, the generally lower the volatile matter. The fixed carbon of coal is the main source of coal thermal energy, and the higher the fixed carbon of coal used as fuel, the better