Patent ID: 6638418
Filing Date: 2003-10-28
Classification: C10G

Abstract:
A hydrocracking process for maximum production of ultra low sulfur diesel which process comprises:a) contacting a first hydrocarbonaceous feedstock and hydrogen with a hydrotreating catalyst in a first hydrotreating reaction zone at reaction conditions including a temperature from about 204Â° to 482Â° C. (400Â° to 900Â° F.) and a pressure from about 3.6 to 17.3 MPa (500 to 2500 psig) and recovering a hydrotreating reaction zone effluent therefrom; b) passing at least a portion of the first hydrotreating reaction zone effluent and a hereinafter described liquid hydrocarbonaceous recycle stream to a hydrocracking reaction zone containing hydrocracking catalyst and operated at reaction zone conditions including a temperature from about 204Â° to 482Â° C. (400Â° to 900Â° F.) and a pressure from about 3.6 to 17.3 MPa (500 to 2500 psig) and recovering a hydrocracking reaction zone effluent therefrom; c) introducing the hydrocracking reaction zone effluent into a high pressure stripper to produce a hydrocarbonaceous vapor stream comprising hydrogen, hydrogen sulfide and hydrocarbons boiling in the diesel range, and a liquid hydrocarbonaceous stream comprising hydrocarbons boiling at and above the diesel range and saturated with hydrogen; d) recycling at least a portion of the liquid hydrocarbonaceous stream produced in step (c) to the hydrocracking zone in step (b) as at least a portion of the liquid hydrocarbonaceous recycle stream; e) fractionating in a fractionation zone at least a portion of the liquid hydrocarbonaceous stream produced in step (c) to produce a first stream of ultra low sulfur diesel and a stream comprising hydrocarbons boiling at a temperature above the diesel range; f) recycling at least a portion of the stream comprising hydrocarbons boiling at a temperature above the diesel range produced in step (e) to the first hydrotreating reaction zone in step (a); g) contacting the hydrocarbonaceous vapor stream from step (c) and a second hydrocarbonaceous feedstock comprising diesel boiling range hydrocarbons with a hydrotreating catalyst in a second hydrotreating reaction zone; and h) fractionating at least a portion of the effluent from the second hydrotreating reaction zone to produce a second stream of ultra low sulfur diesel.