Selective hydrogenation of acetylenes

Abstract

A process for removing acetylenic compounds using unsulfided metallic nickel or unsulfided metallic nickel modified with metallic Mo, Re, Bi or mixtures in which the catalyst is used alone or is used in combination with other acetylenic selective catalysts. The unsulfided metallic nickel catalyst or modified catalyst must be the first catalyst to contact the hydrocarbon stream.

The invention claimed:  
     
         1 . A process for removing acetylenic compounds from hydrocarbon streams, comprising contacting hydrogen and a hydrocarbon feed containing acetylenic compounds with a catalyst comprising a supported unsulfided metallic nickel under hydrogenation conditions to selectively hydrogenate a portion of said acetylenic compounds.  
     
     
         2 . The process according to  claim 1  wherein said unsulfided metallic nickel catalyst is modified with metals of Mo, Re, Bi or mixtures thereof.  
     
     
         3 . A process for removal of acetylenic compounds from hydrocarbon streams comprising: 
 contacting a hydrocarbon feed containing a first concentration of acetylenic compounds and olefins with a first catalyst comprising supported unsulfided metallic nickel in the presence of hydrogen in a reaction zone under conditions of temperature and pressure and hydrogen concentration favoring the hydrogenation of acetylenic compounds and    recovering said hydrocarbon feed having a second concentration of acetylenic compounds lower than said first concentration.    
     
     
         4 . The process according to  claim 3  wherein said unsulfided metallic nickel catalyst is modified with metals of Mo, Re, Bi or mixtures thereof.  
     
     
         5 . The process according to  claim 3  wherein a second catalyst which is selective for hydrogenation of acetylenic compounds is positioned in said reaction zone after said first catalyst.  
     
     
         6 . The process according to  claim 5  wherein said second catalyst comprises supported unsulfided metallic Ni.  
     
     
         7 . The process according to  claim 6  wherein said second catalyst comprises unsulfided metallic nickel catalyst modified with metals of Mo, Re, Bi or mixtures thereof.  
     
     
         8 . The process according to  claim 5  wherein said second catalyst comprises Pd-based catalyst.  
     
     
         9 . The process according to  claim 5  wherein said second catalyst comprises Cu-based catalyst.  
     
     
         10 . The process according to  claim 8  wherein said second catalyst comprises a silver component.  
     
     
         11 . The process according to  claim 8  wherein said second catalyst comprises Pd or Pd and other Group VIII metals and at least two metals selected from Ag, Zn or Bi.  
     
     
         12 . The process according to  claim 9  wherein said second catalyst comprises copper catalyst containing at least one Group VIII metal component, a Ag, Au component or mixtures thereof on an alumina support comprising at least one of the properties of average pore diameter larger than 200 Å or apparent bulk density of less than about 0.70 g/cm 3 .  
     
     
         13 . The process according to  claim 12  wherein said second catalyst comprises copper, zinc, silver promoted with Pd.  
     
     
         14 . The process according to  claim 3  comprising a first reaction zone containing said first catalyst and a second reaction zone containing a second catalyst which is selective for hydrogenation of acetylenic compounds.  
     
     
         15 . The process according to  claim 14  wherein said second catalyst comprises supported unsulfided metallic Ni.  
     
     
         16 . The process according to  claim 14  wherein said second catalyst comprises unsulfided metallic nickel catalyst modified with metals of Mo, Re, Bi or mixtures thereof.  
     
     
         17 . The process according to  claim 14  wherein said second catalyst comprises Pd-based catalyst.  
     
     
         18 . The process according to  claim 14  wherein said second catalyst comprises Cu-based catalyst.  
     
     
         19 . The process according to  claim 17  wherein said second catalyst comprises a silver component.  
     
     
         20 . The process according to  claim 17  wherein said second catalyst comprises a gold component.  
     
     
         21 . The process according to  claim 17  wherein said second catalyst comprises Pd or Pd and other Group VIII metals and at least two metals selected from Ag, Zn or Bi.  
     
     
         22 . The process according to  claim 18  wherein said second catalyst comprises copper catalyst containing at least one Group VIII metal component, a Ag, Au component or mixtures thereof on an alumina support comprising at least one of the properties of average pore diameter larger than 200 Å or apparent bulk density of less than about 0.70 g/cm 3 .  
     
     
         23 . The process according to  claim 22  wherein said second catalyst comprises copper, zinc, and silver promoted with Pd.  
     
     
         24 . The process according to  claim 14  wherein conditions of temperature and pressure and hydrogen concentration favoring the hydrogenation of acetylenic compounds are separately adjusted for each reaction zone.  
     
     
         25 . The process according to  claim 3  wherein said hydrocarbon feed comprises butadiene and other C 4  acetylenic compounds and the temperature in the reaction zone is in the range of 70 to 170° F.  
     
     
         26 . The process according to  claim 3  wherein the unsulfided Ni catalyst is present on the support in amounts in excess of that necessary for the selective hydrogenation.  
     
     
         27 . The process according to  claim 12  wherein the surface area of said support is greater than 40 m 2 /g.