AM-95-35 KEY ELEMENTS IN OPTIMIZING CATALYST SELECTIONS FOR RESID FCC UNITS

Description:

Achieving the optimum activity and yield structure from a commercial Resid FCC Unit (RFCC) is essential to maximizing profitability in today’s modem refinery. Proper catalyst selection is a key element in this optimization. This paper is written to provide FCC Process Engineers with an understanding of some basic elements of RFCC operation. The necessity of using realistic evaluation methods to assure proper RFCC catalyst selection is explained. The differences between Activity limited and Delta Coke limited RFCC operations are elucidated and the related catalyst performance requirements are discussed. The effect of the catalyst to oil ratio on conversion and on catalyst site utilization and poisoning plays a key role in the transition of an RFCC unit from Catalyst Activity limited regime to a Cat-to-Oil limited regime. For the Activity limited operation the catalyst resistance to poisons with the appropriate feedstock will be the most important selection criteria. For the Delta Coke limited operation, a reduction of the commercial delta coke of the catalyst will be crucial. The types of commercial delta coke are discussed and methods for their evaluation are suggested. In both cases the use of realistic catalyst evaluation methods and feedstock will be essential in order to arrive at the correct catalyst selection. Finally, commercial data comparisons illustrate the improvements in product value that can be achieved when the proper catalyst is chosen.