1 Introduction Combination of residue hydrodesulfurization (HDS) and residue fluid catalytic cracking (RFCC) is a unique technology for processing high-sulfur residue. This paper discusses the optimized combination of these two processes. 2 Residue Fluid Catalytic Cracking 2.1 Feed quality In order to ensure economically feasible operation of RFCC, 1 Introduction Combination of residue hydrodesulfurization (HDS) and residue fluid catalytic cracking (RFCC) is a unique technology for processing high-sulfur residue. This paper discusses the optimized combination of these two processes. 2 Residue Fluid Catalytic Cracking 2.1 Feed quality In order to ensure economically feasible operation of RFCC,