Abstract: The feed position and temperature of the absorption and desorption tower in hydrocracking unit are usually designed according to the undercooled liquid feed to the absorption and stabilization system, but the liquid feed is actually saturated. Therefore, the optimization of absorption and desorption tower can greatly influence the material consumption and energy consumption of the unit. The effects of liquid feed position and stripping tower reflux temperature on material loss, energy consumption and operating cost are studied using Pro/II, and some optimization methods are proposed. The optimization results of the absorption and stabilization system in a 1.0 Mt/a hydrocracking unit show that the loss of heavy components in dry gas can be reduced by 37%, the energy consumption can be reduced by 23%, and the benefit can be increased by 1.64 million CNY per year.

Key words: hydrocracking, absorption and desorption tower, feed position, feed temperature