Method for reducing the maximum water concentration in a multi-phase column reactor

Abstract

The present invention relates to a method and apparatus for reducing the maximum water concentration in multi-phase reactors operating at Fischer-Tropsch conditions. In a preferred embodiment of the present invention, a method of reducing the maximum concentration of water in a multi-phase reactor containing an expanded slurry bed and a water-rich slurry region for Fisher-Tropsch synthesis includes changing the flow structure of a predetermined region in the reactor. The flow structure may be changed by introducing a mixing enhancing fluid into the predetermined region, installing baffles into the predetermined region, or by other methods known in the art. Preferably the predetermined region is located between ½ H and H and between ½ R and R, where H is the height of the expanded slurry bed and R is the radius of the reactor.

What is claimed is:  
     
         1 . A Fischer-Tropsch reactor system, comprising: 
 a slurry bed reactor receiving a synthesis gas feed and containing a hydrocarbon synthesis catalyst, said catalyst forming an expanded slurry bed under reaction conditions effective to form a product stream comprising hydrocarbons and water; and    means for changing the flow pattern within the reactor so as to cause mixing of slurry from a predetermined region within the reactor with fluids from the rest of the slurry bed.    
     
     
         2 . The reactor system according to  claim 1  wherein said predetermined region is located between ½ H and H and between ½ R and R, where H is the height of the expanded slurry bed and R is the radius of the reactor.  
     
     
         3 . The reactor system according to  claim 1  wherein said predetermined region is located between ¾ H and H and between ¾ R and R.  
     
     
         4 . The reactor system according to  claim 1 , further comprising a fluid inlet in said predetermined region.  
     
     
         5 . The reactor system according to  claim 1  wherein said flow changing means comprises an inlet for introducing a mixing enhancing fluid into said predetermined region.  
     
     
         6 . The reactor system according to  claim 5  wherein the mixing enhancing fluid is a gas or gas mixture selected from the group comprising synthesis gas, inert gas, methane-rich gas, light hydrocarbons, hydrogen containing gas, tail gas from a Fischer-Tropsch reactor, tail gas from a GTL plant, tail gas from an olefin plant, liquids vaporizing at operating conditions, and combinations thereof.  
     
     
         7 . The reactor system according to  claim 5  wherein the mixing enhancing fluid is a liquid that comprises liquid hydrocarbons from the product stream of the Fischer-Tropsch reactor or from other processes in a Gas-to-Liquids plant.  
     
     
         8 . The reactor system according to  claim 5  wherein said flow changing means comprises at least one mixing enhancing fluid distributor.  
     
     
         9 . The reactor system according to  claim 8  wherein the said mixing enhancing fluid distributor comprises an annular ring having at least one outlet port.  
     
     
         10 . The reactor system according to  claim 8  wherein a plurality of mixing enhancing fluid distributors are positioned at different heights in said predetermined region.  
     
     
         11 . The reactor system according to  claim 8  wherein a plurality of mixing enhancing fluid distributors are positioned at different radial positions in said water-rich slurry region.  
     
     
         12 . The reactor system according to  claim 5  wherein the mixing enhancing fluid is introduced into said predetermined region through at least one nozzle.  
     
     
         13 . The reactor system according to  claim 12  wherein said nozzles are positioned at different heights in the water-rich slurry region.  
     
     
         14 . The reactor system according to  claim 12  wherein said nozzles are positioned at different radial positions in the water-rich slurry region.  
     
     
         15 . The reactor system according to  claim 1  wherein said flow changing means comprises at least one static mixing device in said predetermined region.  
     
     
         16 . The reactor system according to  claim 1  wherein said flow changing means comprises at least one passive movable device in said predetermined region.  
     
     
         17 . The reactor system according to  claim 1  wherein said flow changing means comprises at least one power-driven device in said predetermined region.