Steam cracking to produce olefins

The most important petrochemical process is steam cracking of hydrocarbons to produce ethylene, propylene, C4 olefins and higher unsaturated compounds. Ethylene is the most important basic organic chemical in terms of quantity production worldwide was 40 Mt in 1985. 

Feed material Ethane Propane n-Butane i-Butane Light naphtha Full Raffinate range after naphtha aromatics extraction Kerosene Light gas oil Heavy gas oil Heavy vacuum gas oil 

Feed Ethane Propane n-Butane i-Butane Light Full Raffinate Kerosene Light Heavy Heavy 

Butene Butane C5 fraction C6 Cg nonaromatics Benzene Toluene Cg fraction Styrene C9 fraction (Final boiling point 200 °C) Pyrolysis tar Total 

In the USA, and to some extent in Great Britain and Norway, ethane is the dominant feedstock for steam cracking. It is recovered from wet natural gas and gives high yields of ethylene, hydrogen and methane. From naphtha, the preferred feedstock in Europe and Japan, additional principal products are propylene, C4 hydrocarbons and pyrolysis naphtha as well as highly aromatic pyrolysis tar. 

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