Patent ID: 6843906

Claim:
An integrated hydrotreating process for the desulfurization of a fluid catalytic cracker (FCC) feedstock to achieve low sulfur specifications in FCC produced gasoline and the simultaneous production of an ultra low sulfur diesel stream which process comprises: a) reacting a hydrocarbonaceous feedstock having a majority boiling at a temperature greater than about 371° C. (700° F.) and hydrogen in a first denitrification and desulfurization reaction at reaction zone conditions including a temperature from about 204° C. (400° F.) to 426° C. (800° F.) and a pressure from about 3.5 MPa (500 psig) to about 17.3 MPa (2500 psig) with a catalyst to reduce the sulfur content of the feedstock and to convert less than about 20 volume percent of the feedstock to lower boiling hydrocarbons; b) passing a denitrification and desulfurization reaction zone effluent to a first vapor-liquid separator maintained at a temperature from about 149° C. (300° F.) to about 426° C. (800° F.) to produce a first vapor stream boiling in a range below that of the feedstock and containing diesel boiling range hydrocarbons, and a first liquid stream; c) cooling and partially condensing the first vapor stream to produce in a second vapor-liquid separator, a hydrogen-rich gaseous stream containing hydrogen sulfide and a second liquid stream comprising diesel boiling range hydrocarbons; d) passing the hydrogen-rich gaseous stream containing hydrogen sulfide to an acid gas scrubbing zone to produce a hydrogen-rich gaseous stream having a reduced concentration of hydrogen sulfide; e) passing the first liquid stream to a flash zone to remove dissolved hydrogen and normally gaseous hydrocarbons and then to a fractionation zone; f) passing at least a portion of the second liquid stream to the fractionation zone; g) removing a third liquid stream containing diesel boiling range hydrocarbons from the fractionation zone and passing the third liquid stream and hydrogen to a second denitrification and desulfurization zone to produce a fourth liquid stream containing reduced sulfur content, diesel boiling range hydrocarbons; h) passing at least a portion of the hydrogen-rich gaseous stream having a reduced concentration of hydrogen sulfide to the first and the second desulfurization reaction zones; and i) recovering a fluid catalytic cracking feedstock having a sulfur content lower than the feedstock and having a majority boiling at a temperature greater than about 371° C. (700° F.).