In order to make petroleum coke (green coke) the raw material for graphite electrodes and carbon products, the green coke is calcined. The purpose is to remove volatiles in petroleum coke, increase the degree of graphitization of petroleum coke, reduce resistivity, increase bulk density, and improve the physical and chemical indicators of graphite electrodes.
Calcined petroleum coke meaning?
Calcined petroleum coke is a process of discharging moisture and volatiles from raw materials, and is heated to 1200~1500°C through high temperature. If it is not calcined first, shrinkage and deformation will occur during the subsequent firing of the electrode, causing the electrode to break. Generally, the calcination temperature is higher than the calcination temperature.
During the calcination process, the molecular structure of petroleum coke is constantly changing, reducing chemical activity, increasing volume density, high mechanical strength, reducing electrical resistivity, and improving graphitization.
Petroleum coke calcination temperature
The temperature of the calciner is divided into three zones, the first preheating zone, the charging end is 500~600°C, and the high temperature end is 800~1100°C. The second calcination zone is 1200°C~1300°C. The third section is the cooling zone. Although the maximum temperature of the tank calciner can reach 1300°C, there is a temperature difference of 100°C~150°C between the raw materials for calcining. In order to ensure the quality of calcination, the temperature of the calcination belt needs to be increased between 1250°C and 1350°C.
The calcination temperature of the rotary kiln is 1200~1350°C, and the residence time in the furnace is 30 minutes in Russia, 50-60 minutes in China, and 60~90 minutes in the United States. The calcination temperature of the electric calciner is 1300°C~1400°C.
Petroleum coke calcination plant
There are three types of petroleum coke calcining equipment: tank calciner, rotary kiln, and electric calciner.
Tank calciner, the technology adopted by most small and medium-sized enterprises, the technology is mature and suitable for dispersed calcination
The electric calcining furnace is a vertical resistance furnace with a simple structure, which uses electric energy to convert heat energy to heat to a high temperature to achieve the purpose of calcination.
Rotary kiln calcination is the most widely used technology in the world. 85% of calcined petroleum coke is produced by rotary kiln.