Abstract:

In order to improving the utilization efficiency of hydrocarbons in naphtha, zeolites ZSM-5 was synthesized by hydrothermal method to separate monomethyl isoparaffins from naphtha. The effects of preparation conditions on the properties of zeolites ZSM-5 were investigated using 2-methylpentane/cyclohexane as separation system. The optimum preparation conditions for zeolites ZSM-5 were using n-butylamine as the template, the SiO2/Al2O3 of 80, the aging time of 36h and the crystallizing time of 48 h. The static saturated adsorption capacity of zeolites ZSM-5 synthesized in this paper was 2.39 g 2-methylpentane/(100 g) zeolite at 25 ℃, which is 20% higher than the contrastive zeolites ZSM-5. The total content of normal paraffins and monomethyl isoparaffinsin naphtha was 97.47% after the adsorption separation by zeolites ZSM-5. The potential aromatic contents of naphtha was increased from 23.19% to 34.21%.The content of 30% of normal paraffins and 12% monomethyl isoparaffins was separated from naphtha with synthesized zeolites ZSM-5.

Key words: ZSM-5 zeolite, naphtha, hydrothermal method, monomethyl isoparaffin