Abstract: In order to solve the problem of insufficient utilization of C4 resources as high-value chemicals in refineries, the coupling process of alkane/olefin extractive distillation and low reaction temperature rise hydrogenation process was proposed, and the C4 resources in a refinery were classified and utilized. The pinch technology is applied to optimize the heat exchange process, and realize the normal production and shutdown of the heating furnace, which can greatly save steam consumption by using low-temperature heat. The 600 kt/a unit built by this technology has been successfully started up at one time, the maximum reactor load can reach 120%, the purity (mass fraction) of isobutane product is 99.9% with sulfur mass fraction less than 0.5 μg/g, the purity of n-butane product is 97% with sulfur mass fraction less than 0.5 μg/g, the purity of rich butene is 95%, the actual energy consumption is significantly lower than the design value, and the unit operates stably. It shows that the technology realizes the effective utilization of C4 resources in refineries and creates higher benefits for enterprises.

Key words: refinery, extractive distillation, hydrogenation, isobutane, C₄ olefin