Ethylene is widely used in chemical industry, and its worldwide production(over 109 million tonnes in 2006) exceeds that of any other organic compound. Commercially ethylene is obtained by(1)thermal cracking of hydrocarbons such as ethane, propane, butane, naphtha, kerosene, gasoil, crude oil, etc, (2) auto thermic cracking (partial oxidation) of the above hydrocarbons, (3)recovery from refinery off-gas, (4) recovery from coke-oven gas, and(5) catalytic dehydration of ethyl alcohol or ethyl ether. The thermal cracking process is the most interesting process to produce ethylene commercially .At this project production of ethylene from naphtha is studied. Naphtha, an important feedstock for ethylene production, is a collective of liquid hydrocarbon intermediate oil refining products. It is a mixture of hydrocarbons in the boiling point range of 30-200 C. it is fed to the naphtha cracking furnace. Then, the cracked gas is fed to gasoline fractionator, where it separates the quench oil as a bottom and the cracked gasoline and lighter components as the overhead products. Then, the overhead products are separated in different column.