Patent ID: 7591939

Claim:
A process for providing reduced sulfur fuel and chemical feedstock products, said process comprising: (a) cracking a hydrocarbon feedstock in a riser reactor in a fluid catalytic cracking unit in the presence of a cracking catalyst and a sulfur removal catalyst to produce a stream comprising cracked product and spent catalyst; (b) separating said cracked product and spent catalyst in a separator comprising a separation unit for receiving said cracked product and spent catalyst, the separation unit comprising: (i) a substantially cylindrical internal downcomer pipe having an inlet, a downcomer portion having a vertical window located in a portion of said downcomer and a downcomer floor provided with a solids distribution plate; and (ii) a vapor outlet duct suitable for receiving gases from said vertical window and located concentrically outside said internal downcomer pipe and extending upwardly to produce a reduced sulfur cracked product stream and a spent catalyst stream; (c) steam stripping said spent catalyst in a dense bed stripper; (d) fractionating said reduced sulfur cracked product stream to produce at least a reduced sulfur gasoline stream, a reduced sulfur chemical feedstock stream and a reduced sulfur heavier than gasoline stream; and, (e) obtaining a heavy naphtha from said fractionation in step (d) and recycling said heavy naphtha to said riser reactor, wherein said process provides a net desulfurization of at least 70% of said fuel and chemical feedstock.