Techno-economic feasibility of fluid catalytic cracking unit integrated chemical looping combustion - A novel approach for CO2 capture

Oil refineries are collectively responsible for about 4-6% of the global CO2 emissions, largely because of the regenerator part of the Fluid Catalytic Cracking (FCC) unit (25-35%). An advanced combustion technology, also called chemical looping combustion (CLC), has been recently presented as a novel CO2 capture process for FCC units; however, no study provides the economic feasibility of a CLC-FCC unit. In this study, a techno-economic feasibility of the novel CLC-FCC unit was presented for the first time based on a case study with 50,000 barrels feed per day. A rigorous mass and energy balance estimation shows that 96 vol% of coke regeneration (com-bustion) was achieved in the FCC regenerator by using a stoichiometrically required amount of metal oxide (CuO modified catalysts) at 750 C-degrees for 45 min. The preliminary energy penalty calculations of the proposed CLC-FCC unit (0.21 GJ/ton CO2) is relatively lower compared to the post-combustion (3.1-4.2 GJ/t CO2) via amine solvent and oxy-fuel combustion (1.8-2.5 GJ/t CO2) units reported in the literature. The equipment purchase cost (EPC) is 1.1 times higher than a standalone FCC unit due to the increase in the number of processing equipment required. The cash flow analysis results reveal a yearly basis average CO2 capture cost of 0.0106 US$/kg of CO2 (10.6 US$/ton CO2) for the CLC-FCC unit, which is lower compared to the other conventional CCS technologies i.e. oxy-fuel combustion and post-combustion. Factors such as EPC, capital expenditure (CAPEX), and discount rate significantly influenced the capture cost. In contrast, the CO2 capture cost is not influenced by a change in oxygen carrier and electricity cost.