Study on the integration of fluid catalytic cracking unit in refinery with solvent-based carbon capture through process simulation

Fluid catalytic cracking unit (FCCU) is an important refinery process by cracking heavy hydrocarbons to form lighter valuable products, including gasoline and diesel oil. However, the FCCU also generates the largest amount of CO2 emissions among all the refinery units. To solve this problem, solvent-based carbon capture can be introduced to capture CO2 in the flue gas from FCCU, but the energy consumption from the reboiler of the carbon capture plant will undoubtedly reduce the economic benefits of the refinery. In this paper, solvent-based carbon capture for an FCCU in a real life refinery is studied through process simulation. This study takes into account the process design and heat integration. An industrial FCCU with a feed capacity of over 1.4 million tons vacuum gas oil per year was modelled, and the process model was validated according to industrial operating data. A carbon capture plant model with MEA solvent was also developed in Aspen Plus (R) at pilot scale, and scaled up to match the capacity of the FCC unit. Case studies were performed to analyze the integration of the FCCU with commercial scale carbon capture plant, in which different heat integration options were discussed to reduce the energy consumption. The simulation results indicated that a proper design of heat integration will significantly reduce the energy consumption when the carbon capture plant is integrated with an industrial FCCU.