Catalytic distillation hydroprocessing

Abstract

A method for hydroprocessing a hydrocarbon synthesis product feed to form upgraded fuels and lubricating oils. In a preferred embodiment, the method includes the steps of: (a) contacting a Fischer-Tropsch product with a hydroprocessing catalyst to produce a desired distillate; and (b) counter-currently stripping the desired distillate as it is produced. The method may include distilling the desired distillate or distilling the treated Fischer-Tropsch product.

1 . A method for hydroprocessing a hydrocarbon synthesis product stream comprising liquid hydrocarbons, comprising the steps of: 
 (a) feeding a hydrocarbon synthesis product stream comprising hydrocarbon liquid above a first hydroprocessing catalyst bed, comprising a hydroprocessing catalyst, in a hydroprocessing unit; wherein the hydrocarbon liquid moves downwards through said first hydroprocessing catalyst bed, said first hydroprocessing catalyst bed having a top and a bottom;    (b) feeding a hydrogen-containing gas comprising hydrogen below said first hydroprocessing catalyst bed; wherein the hydrogen-containing gas moves upwards through said first hydroprocessing catalyst bed, counter-current to said hydrocarbon liquid;    (c) converting at least a portion of said hydrocarbon liquid and and a portion of said hydrogen on said hydroprocessing catalyst to produce lighter hydrocarbons; and    (d) vaporizing at least a portion of said lighter hydrocarbons to produce a hydrocarbon vapor as lighter hydrocarbons are formed within the first hydroprocessing catalyst bed, so that said hydrocarbon vapor moves upwards towards the top of the first hydroprocessing catalyst bed, and wherein unconverted hydrogen and said hydrocarbon vapor exit said top of said first hydroprocessing catalyst bed,    wherein the temperature at the top of said first hydroprocessing catalyst bed is lower than the temperature at the bottom of said first hydroprocessing catalyst bed.    
     
     
         2 . The method of  claim 1  further comprising the step of: 
 (e) distilling unconverted hydrogen and said hydrocarbon vapor in a first distillation zone located above the first hydroprocessing catalyst bed, such that a gas stream comprising a portion of unconverted hydrogen and at least one distillate cut are recovered.    
     
     
         3 . The method of  claim 2  wherein at least a portion of said gas stream comprising a portion of unconverted hydrogen is recycled to the hydroprocessing unit and fed below the first hydroprocessing catalyst bed.  
     
     
         4 . The method of  claim 2  further comprising the step of: 
 (f) distilling a portion of the hydrocarbon liquid that drains out of said first hydroprocessing catalyst bed in a second distillation zone located below the first hydroprocessing catalyst bed to vaporize a portion of said hydrocarbon liquid.    
     
     
         5 . The method of  claim 4  wherein step (b) further comprises feeding said hydrogen-containing stream such that said hydrogen flows through said second distillation zone.  
     
     
         6 . The method of  claim 2  further comprising the step of: 
 (f) distilling said distillate cut recovered from the first distillation zone in a second distillation zone located outside of said hydroprocessing unit to produce a heavy distillate product and a light hydrocarbon stream.    
     
     
         7 . The method of  claim 6  further comprising the step of: 
 (g) recycling the light hydrocarbon stream from the second distillation zone to the first distillation zone.    
     
     
         8 . The method of  claim 1  wherein said hydrocarbon synthesis product stream is a product stream derived from a Fischer-Tropsch synthesis.  
     
     
         9 . The method of  claim 1  wherein said hydrocarbon synthesis product stream is substantially free of cyclic hydrocarbons.  
     
     
         10 . The method of  claim 1  wherein said hydrocarbon synthesis product stream comprises wax.  
     
     
         11 . The method of  claim 1  wherein the hydroprocessing unit further comprises a second hydroprocessing catalyst bed adjacent said first hydroprocessing catalyst bed.  
     
     
         12 . The method of  claim 11  wherein the first and second hydroprocessing catalyst beds comprise the same type of hydroprocessing catalyst.  
     
     
         13 . The method of  claim 11  wherein the first and second hydroprocessing catalyst beds comprise different hydroprocessing catalysts.  
     
     
         14 . The method of  claim 11  wherein step (a) comprises feeding the hydrocarbon synthesis product stream comprising hydrocarbon liquid between the first and second hydroprocessing catalyst beds.  
     
     
         15 . The method of  claim 11  wherein the first distillation zone is above said first and second hydroprocessing catalyst beds.  
     
     
         16 . The method of  claim 11  wherein step (b) comprises feeding the hydrogen-containing gas below the first and second hydroprocessing catalyst beds.  
     
     
         17 . The method of  claim 1  wherein the hydroprocessing catalyst is active in hydrocracking.  
     
     
         18 . The method of  claim 1  wherein the hydroprocessing catalyst is active in hydroisomerization.  
     
     
         19 . A method for refining a hydrocarbon synthesis product, comprising the steps of: 
 (a) converting at least a portion of said hydrocarbon synthesis product into a desired distillate in a first catalyst bed located in a vessel, said first catalyst bed having a top and a bottom; and    (b) counter-currently stripping at least a portion of said desired distillate from said hydrocarbon synthesis product as said desired distillate is produced;    wherein said first catalyst bed is operated such that the temperature at said top of said first catalyst bed is lower than the temperature at said bottom of said first catalyst bed.    
     
     
         20 . The method of  claim 19  wherein said hydrocarbon synthesis product comprises a Fischer-Tropsch wax.  
     
     
         21 . The method of  claim 19  wherein said hydrocarbon synthesis product stream is substantially free of cyclic hydrocarbons.  
     
     
         22 . The method of  claim 19  further comprising the step of: 
 (c) distilling in said vessel in a first distillation zone said desired distillate that has been stripped from said hydrocarbon synthesis product.    
     
     
         23 . The method of  claim 22  further comprising the step of: 
 (d) distilling in said vessel in a second distillation zone said hydrocarbon synthesis product that has been subjected to conversion.    
     
     
         24 . The method of  claim 23  wherein step (b) further comprises counter-currently stripping with a vapor stream comprising hydrogen and wherein said vapor stream is fed to said vessel below said second distillation zone.  
     
     
         25 . The method of  claim 24  wherein said hydrocarbon synthesis product is fed to said vessel below said first distillation zone and above said first catalyst bed.  
     
     
         26 . The method of  claim 25  further comprising the step of: 
 (e) distilling in said vessel in a third distillation zone said desired distillate that has been stripped from said hydrocarbon synthesis product and condensing in said third distillation zone a heavier portion of said desired distillate that has been stripped from said hydrocarbon synthesis product.    
     
     
         27 . The method of  claim 24  wherein step (a) comprises cracking in said first catalyst bed in said vessel and wherein said hydrocarbon synthesis product is fed to said vessel in the midst of said first catalyst bed.  
     
     
         28 . The method of  claim 24  wherein step (a) comprises cracking in said first catalyst bed in said vessel, wherein said vessel comprises a second catalyst bed adjacent to said first catalyst bed, and wherein said hydrocarbon synthesis product is fed between said first and second catalyst beds.