Patent ID: 7094332

Claim:
A hydrocracking process for the production of ultra low sulfur diesel wherein the process comprises: (a) reacting a first hydrocarbonaceous feedstock and hydrogen in a hydrocracking zone containing hydrocracking catalyst to produce diesel boiling range hydrocarbons; (b) introducing a hydrocracking zone effluent produced in step (a) and a second hydrocarbonaceous feedstock having a majority boiling at a temperature greater than about 565° C. (1050° F.) into a first desulfurization zone containing desulfurization catalyst to produce a first desulfurization zone effluent stream; (c) passing the first desulfurization zone effluent to a hot, high pressure vapor-liquid separator to recover a vaporous hydrocarbonaceous stream containing hydrogen and a first liquid hydrocarbonaceous stream; (d) introducing the first vaporous hydrocarbonaceous stream containing hydrogen and a third hydrocarbonaceous feedstock comprising diesel boiling range hydrocarbons into a second desulfurization zone containing desulfurization catalyst to produce a second desulfurization zone effluent stream; (e) passing the second desulfurization zone effluent stream to a cold vapor-liquid separator to recover a hydrogen-rich gaseous stream and a second liquid hydrocarbonaceous stream; and (f) passing the first liquid hydrocarbonaceous stream and the second liquid hydrocarbonaceous stream to a fractionation zone to produce a hydrocarbonaceous stream comprising diesel boiling range hydrocarbons and a hydrocarbonaceous stream comprising hydrocarbons boiling at a temperature great than about 565° C. (1050° F.).