Optimized Operation of Fluidized Catalytic Cracking Considering CO2 Fixation and Carbon Pricing

Abstract

Recently, Japan and the European Union have been experiencing declining petroleum demand owing to global initiatives aimed at reducing environmental impact by curtailing CO2 emissions. Consequently, alternative products and operational conditions should be developed to utilize the fluid catalytic cracking (FCC) unit. Using simulation software (Aspen Hysys), this study modeled a typical FCC unit and compared the simulation results with operational data to ensure reproducibility. Two new process models were developed to investigate two scenarios: (i) the slurry discharged from the FCC unit is utilized as a feedstock for the FCC process and (ii) the slurry and fraction obtained from the downstream absorber of the FCC unit are introduced into a delayed coker unit to facilitate carbon fixation. Within an optimum riser outlet temperature (ROT) of 520–530 °C, the yields of gasoline and liquefied petroleum gas increased up to 4%. For profit performance, although ROT of 535–545 °C yielded peak efficiency, the CO2 emissions increased by 70%. Thus, a ROT of 530–540 °C, coupled with a delayed coker unit, can maximize profitability. Furthermore, a correlation graph illustrated the relationship between CO2 emissions and profit for selecting optimal FCC operational conditions.