Abstract: In recent years, with the improvement of China's fuel oil standards and the upgrading of refining units, naphtha, which was formerly used as raw materials for ethylene plant, are mostly used as reforming feedstock, leading to the inadequate supply of ethylene raw materials. And the hydrogenation of butadiene tail gas has gradually increased the probability of using butane as ethylene feedstock. Butane is mainly composed of n-butane and isobutane. The experimental data of butane pyrolysis shows that there is a negative benefit in the co cracking of n-butane and isobutane. The higher the isobutane content, the lower the yield of ethylene, the yields of ethylene and propylene and the yields of ethylene, propylene and butadiene are. Therefore, the isobutane content of butane, which is used as ethylene feedstock, should be reduced as much as possible to improve the yield of ethylene, the yields of ethylene and propylene and the yields of ethylene, propylene and butadiene in butane.

Key words: Ethylene, Diene, Triene, Cracking, Yield