FCC, a prominent conversion technology employed in refineries to transmute heavy oil into lighter counterparts, emerges as one of the primary sources of CO2. Oxy-fuel combustion has demonstrated its potential as a cost-effective technology for carbon capture in FCCUs. Nevertheless, the implementation of oxy-fuel combustion in FCCUs remains at an early stage of development. This PhD project conducted a comprehensive investigation into the application of oxy-fuel combustion in FCCUs, delving into three distinct strata, which commenced with an exploration at the micro-level, ascending to the realm of reactor-level, and culminating in a study of the whole FCC carbon capture system.