Process for reduction of content of sulphur compounds and polyaromatic hydrocarbons in distillate fuels

Abstract

A process for reducing content of sulphur compounds and polyaromatic hydrocarbons in a hydrocarbon feed having a boiling range between 120° C. and 450° C., which process comprises in combination contacting the feed and hydrogen over a hydrotreating catalyst and hydrotreating feed at hydrotreating conditions, cooling the effluent consisting of hydrocarbon, polyaromatic hydrocarbons, hydrogen sulphide and hydrogen-rich gas from the hydrotreating reactor, contacting said effluent and hydrogen gas over a hydrotreating catalyst in a post treat reactor at a temperature appropriate to lower the polyaromatic hydrocarbon content.

1 . A process for reducing content of sulphur compounds and polyaromatic hydrocarbons in a hydrocarbon feed having a boiling range between 120° C. and 450° C., which process comprises 
 contacting the feed and hydrogen in a first step over a hydrotreating catalyst, hydrotreating the feed at hydrotreating conditions, and obtaining a hydrocarbon effluent containing hydrogen and hydrogen sulphide;  
 cooling the effluent; and  
 contacting the cooled effluent with a hydrotreating catalyst in a post treat step at conditions being effective in reduction of content polyaromatic hydrocarbon in the hydrocarbon feed.  
 
     
     
         2 . A process of  claim 1 , wherein the conditions in the post treat step is a temperature being between 50° C. and 150° C. lower than outlet temperature of the hydrotreater.  
     
     
         3 . A process of  claim 1 , wherein LHSV in the post treat reactor is between 2 and 20 times the LHSV in the hydrotreating reactor.  
     
     
         4 . A process of  claim 1 , wherein the post treat step is conducted in a final bed of the hydrotreating reactor.  
     
     
         5 . A process of  claim 1 , wherein the hydrocarbon feed is characterised by having a 50% boiling point between 200° C. and 350° C.  
     
     
         6 . A process of  claim 1 , wherein the hydrotreating catalyst used in the post treat step is a composite of Group VI-B and/or Group VIII metal on a porous refractory inorganic oxide.  
     
     
         7 . A process of  claim 6 , wherein the metals are nickel and molybdenum, or nickel and tungsten.  
     
     
         8 . A process of  claim 7 , wherein the porous refractory inorganic oxide is alumina or silica-alumina.  
     
     
         9 . A process of  claim 1 , wherein the catalyst in the post treat step is presulphided and/or in-situ sulphided.