Petroleum Coke

There are at least four basic types of petroleum coke, namely, needle coke, honeycomb coke, sponge coke and shot coke. Different types of petroleum coke have different micro-structures due to differences in operating variables and nature of feed-stock. Significant differences are also to be observed in the properties of the different types of coke, particularly ash and volatile matter contents.

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Needle coke, also called acicular coke, is a highly crystalline petroleum coke used in the production of electrodes for the steel and aluminium industries and is particularly valuable because the electrodes must be replaced regularly.

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Needle coke is produced exclusively from either FCC decant oil or coal tar pitch.

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Honeycomb coke is an intermediate coke, with ellipsoidal pores that are uniformly distributed. Compared to needle coke, honeycomb coke has a lower coefficient of thermal expansion and a lower electrical conductivity.