CO2 capture from fluid catalytic crackers via chemical looping combustion: Regeneration of coked catalysts with oxygen carriers

Oil refineries are responsible for ∼5% of total global CO2 emissions and approximately 25–35% of these emissions are released from a single unit called Fluid Catalytic Cracking (FCC). Chemical Looping Combustion (CLC) has been recently proposed as a novel CO2 capture method from the regenerator of FCC units as an integrated process of CLC-FCC. In this study, for the first time, the combustion behaviour of three types of cokes, a model FCC coke (which is a low volatile semi-anthracite coal), and cokes deposited on commercial FCC catalysts by n-hexadecane cracking and Vacuum Gas Oil, were comprehensively investigated with oxygen carriers (Co3O4, CuO, and Mn2O3) in a fixed-bed reactor at 700–850 °C. The results demonstrate that a high coke combustion efficiency was achieved with CuO (98 vol %), Co3O4 (91 vol %), and Mn2O3 (91 vol %) at 800 °C for 30 min. CuO was the most effective oxygen carrier, at temperatures greater than 750 °C for 45 min of residence time. These are the regeneration conditions used in the conventional FCC regenerators.