How is graphitized petroleum coke classified?

Graphitized petroleum coke is a solid carbonaceous substance produced by coking petroleum residue and petroleum pitch produced during petroleum processing. Its main element is carbon, and its ash content is very low, generally below 0.5%. The appearance of petroleum coke is black or dark gray honeycomb structure, and the pores in the coke block are mostly oval. Petroleum coke belongs to graphitized carbon. The output of petroleum coke in my country has reached more than 5.5 million tons. Among them, the petroleum coke used to produce carbon materials mainly includes Daqing coke, Fushun coke, Jinzhou coke, Shengli coke, Anqing coke, Nanjing coke, Zhenjiang coke, Jingmen coke, and Jinxi coke. , Huludao Jiao, Changling Jiao.

Graphitized petroleum coke is usually classified in the following four ways:

(1) According to the coking method, it can be divided into delayed coke, kettle coke, fluidized coke and flat coke. At present, delayed coking is produced in large quantities at home and abroad, and only a small amount of still coke is produced.

(2) According to the heat treatment temperature, it can be divided into green coke and calcined coke (scorched). The green coke is prepared by the delayed coking method (500°C), contains a large amount of volatile matter, and has low mechanical strength. Calcined green coke (about 1350°C) obtains calcined coke. Most oil refineries in China only produce coke, and most of the calcination operations are carried out in carbon plants.

(3) According to the sulfur content of coke, it can be divided into three types: high-sulfur coke, medium-sulfur coke and low-sulfur coke.

(4) According to the appearance, structure and properties of graphitized petroleum coke, it is divided into sponge coke, honeycomb coke and needle coke. Sponge coke looks like a sponge, contains a lot of impurities, has many small holes inside, and the coke wall between the holes is very thin, which is not suitable for the production of carbon materials. The honeycomb coke has uniform pore distribution, obvious honeycomb structure and good physical and mechanical properties. This petroleum coke can be used as a raw material for the production of ordinary power graphite electrodes, pre-baked anodes and electric carbon products. There are obvious stripes on the outer surface of the needle coke, and the pores in the coke block are arranged in elongated elliptical shapes. After crushing, they become elongated particles, which can be used as raw materials for the production of high-power and super-power graphite electrodes.