Coal based activated carbon is developed through a series of processes such as carbonization → cooling → activation → washing. Its appearance is generally black cylindrical activated carbon, amorphous coal granular activated carbon, also known as broken carbon. Cylindrical activated carbon, also known as columnar carbon, is generally made from powdered raw materials and binders through kneading, extrusion molding, carbonization, activation and other processes. It can also be extruded with powdered activated carbon and adhesive. It has developed pore structure, good adsorption performance, high mechanical strength, easy repeated regeneration, low cost, etc; It is used for purifying toxic gas, waste gas treatment, industrial and domestic water purification, solvent recovery, etc.