The cracked lighter product rises to the top of the drum and is drawn off. The heavier product remains and, because of the retained heat, cracks ultimately to coke, a solid carbonaceous substance akin to coal, known as petcoke.

Decoking is accomplished by a high-pressure water jet. First the top and bottom heads of the coke drum are removed. Next a hole is drilled in the coke from the top to the bottom of the vessel. Then a rotating stem is lowered through the hole, spraying a water jet sideways. The high-pressure jet cuts the coke into lumps, which fall out the bottom of the drum for subsequent loading into trucks or railcars for shipment.

Cokers produce no liquid residue but yield up to 30 percent petcoke by weight. Much of the low-sulphur product is employed to produce electrodes for the electrolytic smelting of aluminum. Most lower-quality coke is burned as fuel in admixture with coal.

Most of the imported Petcoke( petroleum coke) is used for burning as the fuel materials like power generation, silicon melting, cement industry. This kinds of Petcoke normally have high sulphur, metal content, also have high shot coke content (over 30%, some of them is 100% shot coke).

Petcoke is also widely used to produce Calcined Petroleum Coke (CPC), which will be used to produce Pre-baked Anode or Graphite products. This kinds of petcoke should be sponge coke with low sulphur, ash and metal content.

Petroleum coke can be used in different industries. The major user of high-sulfur petroleum coke are cement plant and power station. The main users of low sulfur petroleum coke are carbon plant, the aluminum industry, iron and steel plants.

As fuel for the cement plant and electric plant, which need a high caloric value and a good grinding; As raw materials for Aluminum and steel plants or carbon factory, whether as artificial graphite electrode and the raw material of anode paste, both need to control sulfur and volatile. The metal content of petroleum coke for graphite electrode production should also be controlled.