Question

Identify the different types of coke.
(A) Honeycomb coke
(B) Needle coke
(C) Sponge coke
(D) All of these

Answer 1

Coke is a carbon rich solid material which is obtained by oil refining. Coke is a by-product of coal that has a very high combustion power. It burns and produces more heat than coal. Major sources of coke are found in Porbandar in India.

Complete Solution :
-Coke is a by-product but is more combustible than coal. That means it creates more energy and smoke than coal when burnt.
- Petroleum coke can be classified into four types namely sponge coke, honeycomb coke, shot coke and needle coke.
- Discussing the option (A), Honeycomb coke has the ellipsoidal pores which are uniformly distributed.
- Honeycomb coke is an intermediate coke and will be having low electrical conductivity and low coefficient of thermal expansion.
- Discussing the option (B), In order to produce the electrodes for the aluminium and the steel industries, a highly crystalline petroleum coke i.e. the needle coke is used. This is very important because the electrodes should be regularly replaced.
- Needle coke can also be called an acicular coke. Needle coke can be produced by two methods namely the fluid catalytic cracking decants oil and the coal tar pitch. Needle coke will have higher thermal conductivity and high thermal expansion coefficient.
- Discussing the option (C), Sponge coke is also a type of coke that is formed from coker shots.
So, the correct answer is “Option D”.

Note: Different types of petroleum coke have different microstructures as there are many differences in operating variables and nature of feedstock. Significant differences are also to be observed in the properties of the different types of coke, particularly ash and volatile matter contents because there are different origins.