Petroleum coke generally has the following four classification methods:
According to the processing method, it can be divided into raw coke and cooked coke.
The former is obtained from the coke tower of the delayed coking unit, also known as raw coke, which contains more volatile matter and has poor strength;

According to the level of sulfur content
It can be divided into high-sulfur coke (the mass content of sulfur is higher than 4%), medium-sulfur coke (sulfur content is 2%~4%) and low-sulfur coke (sulfur content is lower than 2%).
The sulfur content of coke mainly depends on the sulfur content of the raw oil. As the sulfur content increases, the quality of the coke decreases, and its use changes accordingly.

According to the different microstructure
It can be divided into sponge coke and needle coke. The former is porous like a sponge, also known as ordinary coke. The latter is dense and fibrous, also known as high-quality coke;
It is significantly different from sponge coke in properties, and has the characteristics of high density, high purity, high strength, low sulfur content, low ablation amount, low thermal expansion coefficient and good thermal shock resistance; in thermal conductivity, electrical conductivity, magnetic conductivity and All have obvious anisotropy optically; the pores are large and few, slightly elliptical, the cracked surface has a clear texture structure, and the touch is lubricated. Needle coke is mainly produced from residual oil with high content of aromatic hydrocarbons and less content of non-hydrocarbon impurities.

In different forms
It can be divided into needle coke, projectile coke or spherical coke, sponge coke and powder coke.
(1) Needle coke: It has obvious needle-like structure and fiber texture, and is mainly used for high-power and ultra-high-power graphite electrodes in steelmaking.
(2) Sponge coke: high sulfur content, high moisture content, rough surface and high price.
(3) projectile coke or spherical coke: the shape is spherical, the diameter is 0.6~30mm, and the water content is low because of the smooth surface. Generally, it is produced from high-sulfur and high-asphaltene residual oil, which can only be used for power generation, cement and other industrial fuels.
(4) Powder coke: It is produced by radial fluidization coking process, and its particles have high thermal expansion coefficient of volatile content (diameter 0.1~0.4mm) and cannot be directly used in electrode preparation and carbon industry.