Optimization Of Heat Utilization And Operation For FCC Separation System

Catalytic cracking mainly consists of three parts, namely, reaction regeneration system. The main role of FCCU is to transform the atmospheric residue, wax deasphalting residue and heavy distillates into high quality dry gas, liquefied petroleum gas, gasoline and diesel.In this study, with catalytic cracking unit of Fushun Petrochemical Company as research background, the fractionating system and absorption stabilization system was modeled using Aspen plus process simulation software. And it was proved that simulation results were reliabled through the comparison with real industrial data. The model is of great significance for guiding industrial production.The thermal condition of fractionating column was analyzed. The analysis results showed that the top cycle heat load of fractionating column was relatively large, and the middle cycle heat load of fractionating column was relatively small, which was in accordance with the actual production plan of relatively large diesel gasoline ratio. The fractionator hydraulics analysis results showed that the fractionating column tower was operated in good condition. Simulation results showed that the gasoline dry point increasd with the decreasing of top cycle heat load of fractionating column, the diesel dry point increasd with the decreasing of middle cycle heat load of fractionating column. Studies showed that the diesel dry point could be increased by lowering middle cycle, slurry cycle and to increase middle temperature of fractionating column, it would be contributed to simplify the manufacturing process.Absorption stabilization system simulation results showed that the liquefied gas content in the dry gas is lower and energy consumption was higher with the increasing of add absorber. Decreasing feed temperature of desorption column could reduce the amount of circulating liquid gas in the absorption stabilization system, it also would lead to increasing energy consumption of desorption tower, so it is useful to to find the optimum operating point. According to the simulation results, the feasibility of using middle reboiler technology was proved in theory, and process improvement schemes are put forward.