Abstract: In order to exploit the flexibility of C₅/C₆ isomerization unit, and realize the co-production of high octane number isomerization gasoline and high-purity chemical products, with the help of Aspen Plus process simulation software, this paper analyzed the optimization direction of the “single column depentane + one-pass” process of Par-Isom-C₅/C₆ isomerization technology, three kinds of technological process reconstruction schemes of “two columns + one-pass”, “three columns + one-pass” and “multiple columns + one-pass” processes were proposed, and the three upgarding processes simulation and optimization were carried out,respectively. The results showed that the octane number of isomerized gasoline product could be increased by more than 4 with the upgrading schemes, and the “two columns + one-pass” scheme could only increase the octane number of the isomerized gasoline, and could not co-produce chemical products. The “three columns + one-pass” scheme could produce high-purity isopentane and mixed C₄ hydrocarbons, while the “multiple columns + one-pass” scheme could produce high-purity isopentane, mixed C₄ hydrocarbons and cyclopentane product. In addition, all three upgrading schemes were technically feasible, but would increase the energy consumption at different degree, so desirable C₅/C₆ isomerization upgrading process scheme could be selected according to market demand and actual needs.

Key words: C₅/C₆ isomerization, process simulation, technology upgrading, quality and efficiency promoting