Important Terms from A to Z
Petcoke is a solid derived from crude oil, which is mainly used as an energy source, but also widely used in many metallurgy applications – most commonly aluminum and steel production. The starting materials are very heavy oils, for example residues from vacuum distillation. The crude form of these residues that results from cracking is called green coke. This coke contains volatile hydrocarbons incl. nickel and vanadium, which is why it is preferred for use in the heat treatment of steel or as fuel in industrial heat generation. As nickel and vanadium are pollutants, the use of unregulated green coke is not without controversy.
Various refining processes can be used to improve this coke by eliminating certain components: the purer the petcoke, the better its quality. One common processing method is “delayed coking,” where the volatile hydrocarbons and other by-elements contained in the green coke are eliminated at temperatures of up to 1,200°C under exclusion of air. The final product of this refinement process is calcined petcoke, which consists of almost pure carbon. It is denser, more electrically conductive, and is therefore most useful in fabrication and utilization of smelter anodes and electrodes for aluminum and steel production.
With an extremely low concentration of by-elements and a carbon content of over 99%, graphitized petcoke has the highest quality. This ultrapure carbon carrier is used for carburizing steel and foundry products with the highest quality requirements.
Petcoke comes in many different shapes and sizes; from fine dust, to small bee bees, to larger rock-like formations. It is therefore classified as a dry bulk product (similar to coal).
Status: December 2015
All information subject to change. Errors and omissions excepted.