Distillate desulfurization process

Abstract

A process is disclosed for the ultradeep desulfurization of a sulfur-containing distillate feedstock. The hydrodesulfurization process conditions employed in the process of the invention include a hydrogen circulation rate of at least five times the molar consumption rate of hydrogen and a feedstock vaporization of at least 30 mole percent.

That which is claimed is:  
     
         1 . A process for hydrodesulfurizing a sulfur-containing distillate feedstock which process comprises contacting said feedstock with hydrogen in a hydrodesulfurization zone in the presence of a hydrodesulfurization zone catalyst at hydrodesulfurization conditions to produce a desulfurized effluent stream wherein said conditions comprise a hydrogen circulation rate of at least 5 times the molar rate of chemical hydrogen consumption and wherein the percent vaporization of the feedstock in the hydrodesulfurization zone is at least 30 mole percent.  
     
     
         2 . The process of  claim 1  wherein the percent vaporization of the feedstock is at least 40 mole percent.  
     
     
         3 . The process of  claim 1  wherein the percent vaporization of the feedstock is at least 50 mole percent.  
     
     
         4 . The process of  claim 1  wherein the hydrogen circulation rate is at least 10 times the molar rate of chemical hydrogen consumption.  
     
     
         5 . The process of  claim 4  wherein the percent vaporization of the feedstock is at least 40 mole percent.  
     
     
         6 . The process of  claim 4  wherein the percent vaporization of the feedstock is at least 50 mole percent.  
     
     
         7 . The process of  claim 1  wherein the hydrogen circulation rate is at least 20 times the molar rate of chemical hydrogen consumption.  
     
     
         8 . The process of  claim 7  wherein the percent vaporization of the feedstock is at least 40 mole percent.  
     
     
         9 . The process of  claim 7  wherein the percent vaporization of the feedstock is at least 50 mole percent.  
     
     
         10 . The process of  claim 1  wherein the effluent from the hydrodesulfurization zone contains less than about 50 ppmw sulfur.  
     
     
         11 . The process of  claim 4  wherein the effluent from the hydrodesulfurization zone contains less than about 50 ppmw sulfur.  
     
     
         12 . The process of  claim 7  wherein the effluent from the hydrodesulfurization zone contains less than about 50 ppmw sulfur.  
     
     
         13 . The process of  claim 1  wherein the effluent from the hydrodesufurization zone contains less than about 15 ppmw sulfur.  
     
     
         14 . The process of  claim 4  wherein the effluent from the hydrodesufurization zone contains less than about 15 ppmw sulfur.  
     
     
         15 . The process of  claim 7  wherein the effluent from the hydrodesufurization zone contains less than about 15 ppmw sulfur.  
     
     
         16 . The process of  claim 1  wherein the effluent from the hydrodesulfurization zone contains less than about 10 ppmw sulfur.  
     
     
         17 . The process of  claim 4  wherein the effluent from the hydrodesulfurization zone contains less than about 10 ppmw sulfur.  
     
     
         18 . The process of  claim 7  wherein the effluent from the hydrodesulfurization zone contains less than about 10 ppmw sulfur.  
     
     
         19 . The process of  claim 1  wherein the hydrodesulfurization zone comprises a multi-stage process, wherein an upstream stage is operated at conventional hydrodesulfurization conditions and a downstream stage is operated at conditions that include a hydrogen circulation rate of at least 5 times the molar rate of chemical hydrogen consumption and wherein the percent vaporization of the feedstock to the downstream stage is at least 30 mole percent.