Inventories of SO2 and particulate matter emissions from fluid catalytic cracking units in petroleum refineries

Fluid catalytic cracking (FCC) of heavy ends to high value liquid fuels is a common unit operation in oil refineries. In this process the heavy feedstock which contains sulphur is cracked to light products. Sulphur content is hence redistributed in the liquid and gaseous products and coke of the catalyst used in this process. The coke is later burnt in the regenerator releasing sulphur into the discharged flue gas as SO2. In the present work, comprehensive emission inventories for a FCC unit in a typical oil refinery are prepared. These inventories are based on calculations which assume complete combustion of catalyst coke in the regenerator. Yearly material balances for both SO2 and particulate matters (PM) emissions are carried out taking into account seasonal variations in the operation of the process unit. The results presented in this paper reflect the variation of sulphur in feedstock originating from various units in the refinery. The refinery operations are not dependant on seasons but controlled by market driven conditions to maximize the profit. The seasonal impact on refinery emissions is minimal due to its operation at optimum capacity fulfilling the international market demand. The data presented and analyzed here can be used to assess the hazardous impact of SO2 and particulate matter (PM) emissions on surrounding areas of the refinery