System and process for pyrolysis gasoline hydrotreatment

Abstract

Systems and processes for the hydrotreatment of pyrolysis gasoline comprising reactors, monolithic catalyst beds and hydrogen-containing treatment gases that allow for improved efficiency and productivity over conventional trickle bed processes and systems for such hydrotreatment.

We claim:  
     
         1 . A process for hydrotreating pyrolysis gasoline feed, comprising the step of: 
 contacting said pyrolysis gasoline feed with a hydrogen-containing treatment gas in the presence of at least one catalyst bed comprising monolithic catalyst to provide reacted pyrolysis gasoline product.    
     
     
         2 . The process of  claim 1  wherein said monolithic catalyst comprises an Al 2 O 3 -containing catalyst support surface of gamma-alumina, theta-alumina, or combinations thereof.  
     
     
         3 . The process of  claim 1  wherein said monolith catalyst alumina support surface is a coating on a cordierite monolith.  
     
     
         4 . The process of  claim 1 , wherein said monolithic catalyst comprises a metal hydrogenation catalyst component selected from the group consisting of nickel, platinum, palladium, rhodium, ruthenium, silver, iron, copper, cobalt, chromium, iridium, tin, and mixtures and alloys thereof.  
     
     
         5 . The process of  claim 1 , wherein said monolithic catalyst has a cell density of from about 10-2000 cpsi.  
     
     
         6 . The process of  claim 1 , wherein said contacting step is carried out at about 20° C. to about 350° C.  
     
     
         7 . The process of  claim 1 , wherein said contacting is carried out at a pressure of about 5 bar to about 100 bar.  
     
     
         8 . The process of  claim 1 , wherein said contacting is carried out at a liquid hourly space velocity greater than 0.1 hr − .  
     
     
         9 . The process of  claim 1  wherein said contacting is carried out at a volumetric gas to liquid ratio of 0.1 to 10:1.  
     
     
         10 . The process of  claim 1 , wherein said hydrogen-containing treatment gas comprises at least about 50 mol % of molecular hydrogen.  
     
     
         11 . The process of  claim 1  wherein said pyrolysis gasoline feed flows through multiple catalyst beds.  
     
     
         12 . The process of  claim 11 , wherein said at least a portion of the hydrogen-containing treatment gas is introduced between said catalyst beds.  
     
     
         13 . The process of  claim 11  wherein said feed flows through two to four catalyst beds.  
     
     
         14 . The process of  claim 1  wherein said contacting provides a conversion of dienes in said pyrolysis gasoline feed of greater than 10%.  
     
     
         15 . The process of  claim 1 , wherein a liquid portion of said reacted pyrolysis gasoline is recycled.  
     
     
         16 . A system for hydrotreating pyrolysis gasoline feed comprising one or more reactor vessels comprising at least one monolithic catalyst bed, wherein each of said one or more reactor vessels further comprises at least one feed inlet, at least one effluent outlet, and at least one hydrogen-containing treatment gas inlet.  
     
     
         17 . The system of  claim 16 , wherein a portion of liquid effluent from said reactor is recycled to the inlet of at least one of the reactors.  
     
     
         18 . The system of  claim 16 , wherein at least one of said reactor vessels comprises more than one catalyst bed.  
     
     
         19 . The system of  claim 18  wherein hydrogen-containing treatment gas is introduced between catalyst beds through said hydrogen-containing treatment gas inlet.  
     
     
         20 . The system of  claim 16  wherein hydrogen containing gas is added to maintain a gas to liquid volumetric ratio above 0.5:1 at all points in the reactor.