After distilling process, crude is turned into residue and petroleum pitch. Through the coking process, they finally turn into petroleum gas, gasoline, diesel and petroleum coke. The productivity of petroleum coke is 10%-25% of the raw material for coking.
What is petroleum coke?
Petroleum passes through a coking unit, being cooked at 500~550℃ to produce black solid coke. Coke is irregularly shaped black particles with metallic luster. The particles of coke have a porous structure which closes to natural graphite with low resistance and high bulk density, so petroleum coke is the raw material for graphite electrodes.
What is petroleum coke used for?
According to the sulfur content, petroleum coke is classified into high-sulfur coke (sulfur content>3%) and low-sulfur coke (sulfur content<3%). High-sulfur coke is used in chemical production, such as the manufacture of televisions, silicon carbide, etc., and can also be used as fuel for cement plants and power plants. Low-sulfur coke is used to produce electrode paste (for aluminum plants) and graphite electrodes (for steel plants), especially high-quality low-sulfur coke can be used to produce graphite electrodes and charcoal additives.
Petroleum coke production process
Delayed coking is an advanced coking process, which requires a cyclically operated delayed coking device.
In the delayed coking process, a horizontal tube heating furnace is usually used. Under the conditions of high flow rate and short residence time, the materials are heated to the reaction temperature of 490~510℃ and then enter the coke tower. Under certain temperature, residence time and pressure conditions in the coke tower, the materials undergo cracking and condensation reactions to generate gas, gasoline, diesel, wax oil and coke. Due to the short residence time of the material in the heating furnace tube, only a shallow thermal cracking reaction occurs. After the material quickly passes through the heating furnace tube and obtains the energy required for the reaction, its cracking and condensation coke formation reaction is "delayed" to occur in the coke drum downstream of the heating furnace. So, this process is called "delayed coking".