Petroleum coke

Petroleum coke is a solid that is mainly made of carbon. It is similar to coke, but it is gotten from petroleum (coke is made from coal). Petroleum coke can be used as an industrial fuel, but there are very toxic by-products based on nickel and vanadium which make this a problem. Petroleum coke is also used in the aluminum industry, and in the heat treatment of steel and iron. Petroleum coke may be kept in a pile near an oil refinery ready for sale.
Types.
There are four types of petroleum coke. They are: needle coke, honeycomb coke, sponge coke and shot coke. Different types of petroleum coke have different properties and microstructures.
Needle coke is a crystalline petroleum coke. It is also called acicular coke. It is used in making electrodes for the steel and aluminium industries. Needle coke is made only from either fluid catalytic cracking (FCC) decant oil or coal tar pitch.
Honeycomb coke is an intermediate coke. Compared to needle coke, honeycomb coke has a lower coefficient of thermal expansion and a lower electrical conductivity.
Composition.
The chemicals inside petroleum coke depends on the petroleum feed stock used. It is mainly always made of carbon. It is also sometimes made up of hydrogen, nitrogen, sulfur and so on.