Selective ring opening process for producing diesel fuel with increased cetane number

Abstract

A process, preferably in a counter-current configuration, for selectively cracking carbon-carbon bonds of naphthenic species using a low acidic catalyst, preferably having a crystalline molecular sieve component and carrying a Group VIII noble metal. The diesel fuel products are higher in cetane number and diesel yield.

We claim:  
     
         1 . A process for selectively producing diesel fuels from a hydrocarbon feed comprising contacting said hydrocarbon feed with a hydrogen containing gas, and contacting said liquid product effluent under superatmospheric conditions with a selective ring-opening catalyst comprising 
 a large pore crystalline molecular sieve material component having a faujasite structure and an alpha acidity of less than 1, and    a group VIII noble metal component.    
     
     
         2 . The process as described in    claim 1    further comprising operating said process in a counter-current configuration.  
     
     
         3 . The process as described in    claim 1    wherein said crystalline sieve material component is zeolite USY.  
     
     
         4 . The process as described in    claim 1    wherein said alpha acidity is about 0.3 or less.  
     
     
         5 . The process as described in    claim 1    wherein said Group VIII noble metal component is selected from the elemental group consisting of platinum, palladium, iridium, and rhodium, or a combination thereof.  
     
     
         6 . The process as described in    claim 5    wherein said Group VIII noble metal component is platinum.  
     
     
         7 . The process as described in    claim 1    wherein the particle size of said Group VIII noble metal component is less than about 10 Å.  
     
     
         8 . The process as described in    claim 1    wherein the content of said Group VIII noble metal component is between 0.1 and 5 wt % of said catalyst.  
     
     
         9 . The process as described in    claim 6    wherein the platinum is dispersed on said crystalline molecular sieve component, said dispersion being characterized by an H/Pt ratio of between 1.1 and 1.5.  
     
     
         10 . The process as described in    claim 1    wherein said hydrocarbon feed is contacted with said catalyst at a pressure from about 400 to about 1000 psi H 2 , a temperature from about 544° F. to about 700° F., a space velocity of about 0.3 to about 3.0 LHSV, and a hydrogen circulation rate of about 1400 to about 5600 SCF/bbl.