Objective The cracking feedstock and the process conditions are optimized for producing more propylene from naphtha resources.

Methods The cracking feedstock and the yield of propylene in the cracking product of naphtha from six different producing areas under different process conditions were compared and analyzed by using the bench scale pyrolysis apparatus(BSPA) of KBR company.

Results Urumqi Petrochemical company naphtha has the highest yield of propylene, which is 16.19%. Compared with the raw material composition, it also has the highest mass fraction of isoalkanes, which is 52.58%. Under the conditions of residence time 100 ms, water-oil mass ratio 0.6 and cracking temperature 860 ℃, the propylene yield of naphtha in No.2 tank farm of Lanzhou Petrochemical company is 15.50%.

Conclusions The naphtha with high quality fraction of isoalkane may produce more propylene. At the same time, under the premise of not pursuing the maximum yield of ethylene and propylene, relatively low cracking temperature and high water-oil mass ratio are conducive to the improvement of the yield of propylene. According to the economic benefit estimation results of naphtha from different producing areas, it is found that in the selection of naphtha cracking feedstock for productive propylene, factors such as the yield of ethylene, propylene and butadiene, energy consumption, market price of olefin, and coking problem should be combined in order to obtain the maximum economic benefit.