What is the aim of cracking naphtha???????

Steam cracking is a petrochemical process in which saturated hydrocarbons (such as Naphtha) are broken down into smaller, often unsaturated, hydrocarbons.
It is the principal industrial method and the aim for producing different products such as the lighter alkenes (or commonly olefins), including ethene (or ethylene) and propene (or propylene).
In steam cracking, a gaseous or liquid hydrocarbon feed like Naphtha, LPG or Ethane is diluted with steam and then briefly heated
The products produced in the reaction depend on the composition of Naphtha, the hydrocarbon to steam ratio and on the cracking temperature and furnace residence time.
Light naphthas gives product streams rich in the lighter alkenes, including ethylene, propylene, and butadiene. Heavy naphthas gives some of these, but also give products rich in aromatic hydrocarbons and hydrocarbons suitable for inclusion in gasoline or fuel oil. The process also results in the slow deposition of coke, a form of carbon, on the reactor walls.
For details, pleaser refer:
http://en.wikipedia.org/wiki/Steam_crackers

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