System and process for fischer-tropsch conversion

Abstract

A system for converting carbon monoxide and hydrogen gas into C2+ hydrocarbons including at least one high shear mixing device comprising at least one rotor and at least one stator separated by a shear gap, wherein the high shear mixing device is capable of producing a tip speed of the at least one rotor of greater than 22.9 m/s (4,500 ft/min), and a pump configured for delivering a fluid stream comprising liquid medium to the high shear mixing device.

1 . A system for converting carbon monoxide gas and hydrogen gas into C2+ liquid and gaseous hydrocarbons, the system comprising:
 at least one high shear mixing device comprising at least one rotor and at least one stator separated by a shear gap, wherein the shear gap is the minimum distance between the at least one rotor and the at least stator, and wherein the high shear mixing device is capable of producing a tip speed of the at least one rotor of greater than 22.9 m/s (4,500 ft/min); and   a pump configured for delivering a fluid stream comprising liquid medium to the high shear mixing device.   
     
     
         2 . The system of  claim 1 , further comprising:
 a Fischer Tropsch reactor fluidly connected to an outlet of the external high shear device and having an outlet for a product stream comprising liquid hydrocarbons.   
     
     
         3 . The system of  claim 2  wherein the reactor is a slurry reactor. 
     
     
         4 . The system of  claim 3  further comprising a separator, wherein the product stream further comprises catalyst and wherein the separator comprises an inlet connected to the outlet for the product stream and an outlet for a catalyst slurry stream from which at least a portion of the liquid hydrocarbons have been removed, and an outlet for a stream comprising liquid hydrocarbons. 
     
     
         5 . The system of  claim 2  further comprising a recycle line connecting the outlet for the catalyst slurry stream and an inlet to the Fischer-Tropsch reactor. 
     
     
         6 . The system of  claim 1  wherein the at least one high shear mixing device is configured for producing a dispersion of hydrogen and carbon monoxide gas bubbles in a liquid phase, wherein the dispersion has a mean bubble diameter of less than 5 μm. 
     
     
         7 . The system of  claim 1  wherein the at least one high shear mixing device is capable of producing a tip speed of the at least one rotor of at least 20.3 m/s (4000 ft/min). 
     
     
         8 . The system of  claim 1  comprising at least two high shear mixing devices. 
     
     
         9 . The system of  claim 1 , wherein the shear gap comprises a width in the range of about 0.025 mm to about 10 mm, and wherein the rotor and the stator each comprise at least one grooved surface. 
     
     
         10 . In a system for converting synthesis gas to C2+ hydrocarbons, including a Fischer Tropsch reactor and a Fischer-Tropsch catalyst that catalyzes the conversion of synthesis gas to C2+ hydrocarbons, the improvement comprising:
 an external high shear device upstream of the reactor, the external high shear device comprising an inlet for a fluid stream comprising synthesis gas and a liquid medium, and at least one generator comprising a rotor and a stator having a shear gap therebetween, wherein the high shear device provides an energy expenditure of greater than 1000 W/m 3  of fluid.   
     
     
         11 . The system of  claim 10  wherein the high shear device comprises at least two generators. 
     
     
         12 . The system of  claim 11  wherein the shear rate provided by one generator is greater than the shear rate provided by another generator. 
     
     
         13 . The system of  claim 11 , wherein the shear gap is the minimum distance between the rotor and the stator, wherein the shear gap comprises a width in the range of about 0.025 mm to about 10 mm, and wherein the rotor and the stator each comprise at least one grooved surface. 
     
     
         14 . A method for forming C2+ hydrocarbons, the method comprising:
 forming a dispersion comprising synthesis gas bubbles dispersed in a liquid phase comprising hydrocarbons in a high shear device, wherein the average bubble diameter of the synthesis gas bubbles is in the range from about greater than 400 nm to less than 1 μm, and wherein the high shear device comprises at least one rotor and at least one stator;   introducing the dispersion into a reactor; and   removing a product stream comprising liquid hydrocarbons from the reactor.   
     
     
         15 . The method of  claim 14 , wherein the at least one rotor and at least one stator are separated by a shear gap width in the range of about 0.001 inch to about 0.125 inch. 
     
     
         16 . The method of  claim 14  wherein the reactor comprises Fischer-Tropsch catalyst and wherein the method further comprises circulating at least a portion of the product stream to the high shear device, wherein the high shear device comprises at least a first and second generator, and wherein a first shear rate provided by the first generator is greater than a second shear rate provide by the second generator. 
     
     
         17 . The method of  claim 16  wherein the at least a portion of the product stream circulated to the high shear device comprises Fischer-Tropsch catalyst, wherein the first generator comprises at least one rotor and at least one stator separated by a fixed shear gap width, and wherein the second generator comprises at least a second rotor and a second stator separated by a variable shear gap width. 
     
     
         18 . The method of  claim 16  wherein the at least a portion of the product stream circulated to the high shear device is substantially catalyst-free, wherein the first generator comprises a rotor and a stator separated by a clearance, and wherein the rotor and the stator each comprise at least one grooved surface. 
     
     
         19 . The method of  claim 14  wherein forming the dispersion comprises subjecting a mixture of the synthesis gas and the liquid phase to a shear rate of greater than about 20,000 s −1 , wherein the high shear device comprises a flow path, and wherein the shear rate varies with a longitudinal position along the flow path. 
     
     
         20 . The method of  claim 14  wherein the high shear device comprises at least one rotor, and wherein the at least one rotor is rotated at a tip speed of at least 22.9 m/s (4,500 ft/min) during formation of the dispersion.