Desulfurization system with enhanced fluid/solids contacting

Abstract

A method and apparatus for removing sulfur from a hydrocarbon-containing fluid stream wherein desulfurization is enhanced by improving the contacting of the hydrocarbon-containing fluid stream and sulfur-sorbing solid particulates in a fluidized bed reactor.

What is claimed is:  
     
         1 . A desulfurization unit comprising: 
 a fluidized bed reactor defining an elongated upright reaction zone within which finely divided solid sorbent particulates are contacted with a hydrocarbon-containing fluid stream to thereby provide a desulfurized hydrocarbon-containing stream and sulfur-loaded sorbent particulates, wherein said reactor includes a series of vertically spaced contact-enhancing members generally horizontally disposed in said reaction zone, wherein each of said contact-enhancing members includes a plurality of substantially parallelly extending laterally spaced elongated baffles, wherein said elongated baffles of adjacent ones of said contact-enhancing members extend transverse to one another at a cross-hatch angle in the range of from about 60 to about 120 degrees;    a fluidized bed regenerator for contacting at least a portion of said sulfur-loaded particulates with an oxygen-containing regeneration stream to thereby provide regenerated sorbent particulates; and    a fluidized bed reducer for contacting at least a portion of said regenerated sorbent particulates with a hydrogen-containing reducing stream.    
     
     
         2 . A desulfurization unit in accordance with  claim 1 , wherein each of said contact-enhancing members defines an open area through which said hydrocarbon-containing fluid stream and said sorbent particulates may pass, wherein said open area of each of said contact-enhancing members is in the range of from about 40 to about 90 percent of the cross-sectional area of said reaction zone at the vertical location of that respective contact-enhancing member.  
     
     
         3 . A desulfurization unit in accordance with  claim 2 , wherein the vertical spacing between adjacent ones of said contact-enhancing members is in the range of from about 0.02 to about 0.5 times the height of said reaction zone.  
     
     
         4 . A desulfarization unit in accordance with  claim 3 , wherein each of said baffles has a generally cylindrical outer surface.  
     
     
         5 . A desulfurization unit in accordance with  claim 1 , wherein the height of said reaction zone is in the range of from about 25 to about 75 feet and the width of the reaction zone is in the range of from about 3 to about 8 feet.  
     
     
         6 . A desulfurization unit in accordance with  claim 5 , wherein the vertical spacing between adjacent ones of said contact-enhancing members is in the range of from about 0.05 to about 0.2 times the height of said reaction zone.  
     
     
         7 . A desulfurization unit in accordance with  claim 6 , wherein each of said contact-enhancing members defines an open area through which said hydrocarbon-containing fluid stream and said sorbent particulates may pass, wherein said open area of each of said contact-enhancing members is in the range of from about 55 to about 75 percent of the cross-sectional area of said reaction zone at the vertical location of that respective contact-enhancing member.  
     
     
         8 . A desulfurization unit in accordance with  claim 7 , wherein said cross-hatch angle is in the range of from 80 degrees to about 100 degrees.  
     
     
         9 . A desulfurization unit in accordance with  claim 8 , wherein said elongated baffles of adjacent ones of said contact-enhancing members extend substantially perpendicular to one another.  
     
     
         10 . A desulfurization unit in accordance with  claim 1 , further comprising a first conduit for transporting said sulfur-loaded sorbent particulates from said reactor to said regenerator; a second conduit for transporting said regenerated sorbent particulates from said regenerator to said reducer; and a third conduit for transporting said reduced sorbent particulates from said regenerator to said reactor.  
     
     
         11 . A desulfurization unit in accordance with  claim 10 , further comprising a reactor lockhopper fluidly disposed in said conduit, wherein said reactor lockhopper is operable to transition the sulfur-loaded sorbent particulates from a high-pressure hydrocarbon environment to a low-pressure oxygen environment.  
     
     
         12 . A desulfurization unit in accordance with  claim 11 , further comprising a reactor receiver disposed in the said first conduit upstream of said reactor lockhopper, wherein said reactor receiver cooperates with said reactor lockhopper to transition the flow of said sulfur-loaded sorbent in said first conduit from continuous to batch.  
     
     
         13 . A fluidized bed reactor system comprising: 
 an elongated upright vessel defining a reaction zone;    a gaseous hydrocarbon-containing stream flowing upwardly through said reaction zone at a superficial velocity in the range of from about 0.25 to about 5.0 ft/s;    a fluidized bed of solid particulates substantially disposed in the reaction zone, wherein said solid particulates are fluidized by the flow of said gaseous hydrocarbon-containing stream therethrough; and    a series of vertically spaced contact-enhancing members generally horizontally disposed in said reaction zone, wherein each of said contact-enhancing members includes a plurality of substantially parallelly extending laterally spaced elongated baffles, wherein said elongated baffles of adjacent ones of said contact-enhancing members extend transverse to one another at a cross-hatch angle in the range of from 60 degrees to about 120 degrees.    
     
     
         14 . A fluidized bed reactor system in accordance with  claim 13 , wherein the WHSV in said reaction zone is in the range of from about 2 to about 12 hr −1 .  
     
     
         15 . A fluidized bed reactor system in accordance with  claim 14 , wherein said solid particulates have a mean particle size in the range of from about 20 to about 150 microns.  
     
     
         16 . A fluidized bed reactor system in accordance with  claim 15 , wherein said solid particulates have a density in the range of from about 0.5 to about 1.5 g/cc.  
     
     
         17 . A fluidized bed reactor system in accordance with  claim 16 , wherein said hydrocarbon-containing stream has a hydrogen to hydrocarbon molar ratio in the range of from about 0.1:1 to about 3:1.  
     
     
         18 . A fluidized bed reactor system in accordance with  claim 13 , wherein said superficial velocity is in the range of from about 0.5 to about 2.5 ft/sec.  
     
     
         19 . A fluidized bed reactor system in accordance with  claim 18 , wherein the WHSV in said reaction zone is in the range of from about 3 to about 8hr −1 .  
     
     
         20 . A fluidized bed reactor system in accordance with  claim 19 , wherein said solid particulates have a mean particle size in the range of from about 50 to about 100 microns.  
     
     
         21 . A fluidized bed reactor system in accordance with  claim 20 , wherein said solid particulates have a density in the range of from about 0.8 to about 1.3 g/cc.  
     
     
         22 . A fluidized bed reactor system in accordance with  claim 21 , wherein said hydrocarbon-containing stream has a hydrogen to hydrocarbon molar ratio in the range of from about 0.2:1 to about 1:1.  
     
     
         23 . A fluidized bed reactor system in accordance with  claim 22 , wherein said hydrocarbon-containing stream comprises a hydrocarbon selected from the group consisting of gasoline, cracked-gasoline, diesel fuel, and mixtures thereof.  
     
     
         24 . A fluidized bed reactor system in accordance with  claim 13 , wherein the ratio of the height of said fluidized bed to the width of said fluidized bed is in the range of from about 2:1 to about 7:1.  
     
     
         25 . A fluidized bed reactor system in accordance with  claim 24 , wherein the density of the fluidized bed is in the range of from about 30 to about 50 lb/ft 3 .  
     
     
         26 . A fluidized bed reactor for contacting an upwardly flowing gaseous hydrocarbon-containing stream with solid particulates, said fluidized bed reactor comprising: 
 an elongated upright vessel defining a lower reaction zone within which said solid particulates are substantially fluidized by said gaseous hydrocarbon-containing stream and an upper disengagement zone within which said solid particulates are substantially disengaged from said hydrocarbon-containing stream; and    a series of vertically spaced contact-enhancing members generally horizontally disposed in said reaction zone, wherein each of said contact-enhancing members includes a plurality of substantially parallelly extending laterally spaced elongated baffles, wherein said elongated baffles of adjacent ones of said contact-enhancing members extend transverse to one another at a cross-hatch angle in the range of from 60 degrees to about 120 degrees.    
     
     
         27 . A fluidized bed reactor in accordance with  claim 26 , wherein the vertical spacing between adjacent ones of said contact-enhancing members is in the range of from about 0.02 to about 0.5 times the height of said reaction zone.  
     
     
         28 . A fluidized bed reactor in accordance with  claim 27 , wherein each of said contact-enhancing members defines an open area through which said hydrocarbon-containing stream and said solid particulates may pass, wherein said open area of each of said contact-enhancing members is in the range of from about 40 to about 90 percent of the cross-sectional area of said reaction zone at the vertical location of that respective contact-enhancing member.  
     
     
         29 . A fluidized bed reactor in accordance with  claim 28 , wherein the height to width ratio of said reaction zone is in the range of from about 2:1 to about 15:1.  
     
     
         30 . A fluidized bed reactor in accordance with  claim 29 , wherein the maximum cross-sectional area of said disengagement zone is at least two times larger than the maximum cross-sectional area of said reaction zone.  
     
     
         31 . A fluidized bed reactor in accordance with  claim 26 , wherein the height of said reaction zone is in the range of from about 25 to about 75 feet and the width of the reaction zone is in the range of from about 3 to about 8 feet.  
     
     
         32 . A fluidized bed reactor in accordance with  claim 31 , wherein the vertical spacing between adjacent ones of said contact-enhancing members is in the range of from about 0.05 to about 0.2 times the height of said reaction zone.  
     
     
         33 . A fluidized bed reactor in accordance with  claim 32 , wherein each of said contact-enhancing members defines an open area through which said hydrocarbon-containing stream and said solid particulates may pass, wherein said open area of each of said contact-enhancing members is in the range of from about 55 to about 75 percent of the cross-sectional area of said reaction zone at the vertical location of that respective contact-enhancing member.  
     
     
         34 . A fluidized bed reactor in accordance with  claim 33 , wherein each of said baffles has a generally cylindrical outer surface.  
     
     
         35 . A fluidized bed reactor in accordance with  claim 34 , wherein said elongated baffles of adjacent ones of said contact-enhancing members extend substantially perpendicular to one another.  
     
     
         36 . A fluidized bed reactor in accordance with  claim 35 , wherein each of said baffles is a generally cylindrical bar or tube having a diameter in the range of from about 1.5 to about 3 inches and wherein said baffles are laterally spaced from one another in the range of from about 4 to about 8 inches on center.  
     
     
         37 . A fluidized bed reactor in accordance with  claim 26 , further comprising a distributor plate defining the bottom of said reaction zone, wherein said distributor plate defines a plurality of holes for allowing the hydrocarbon-containing stream to flow upwardly through said distributor plate and into said reaction zone.  
     
     
         38 . A fluidized bed reactor in accordance with  claim 37 , wherein said distributor plate has in the range of from about 15 to about 90 of said holes.  
     
     
         39 . A fluidized bed reactor in accordance with  claim 37 , wherein said distributor plate has in the range of from about 30 to about 60 of said holes.  
     
     
         40 . A fluidized bed reactor in accordance with  claim 26 , wherein said vessel defines a fluid inlet for receiving said gaseous hydrocarbon-containing stream in said reaction zone, a fluid outlet for discharging said gaseous hydrocarbon-containing stream from said disengagement zone, a solids inlet for receiving said solid particulates in said reaction zone, and a solids outlet for discharging said solid particulates from said reaction zone, wherein said solids inlet, said solids outlet, said fluid inlet, and said fluid outlet are separate from one another.  
     
     
         41 . A fluidized bed reactor in accordance with  claim 40 , further comprising a filter positioned proximate said fluid outlet and operable to allow said gaseous hydrocarbon-containing stream to flow through said fluid outlet while blocking the passage of said solid particulates through said fluid outlet.  
     
     
         42 . A fluidized bed reactor in accordance with  claim 26 , wherein the maximum cross-sectional area of said disengagement zone is at least three times larger than the maximum cross-sectional area of said reaction zone.  
     
     
         43 . A fluidized bed reactor in accordance with  claim 42 , wherein said reaction zone is generally cylindrical and said disengagement zone includes a lower generally frustoconical section and an upper generally cylindrical section.  
     
     
         44 . A fluidized bed reactor in accordance with  claim 43 , wherein the height to width ratio of said reaction zone is the range of from about 4:1 to about 8:1.  
     
     
         45 . A desulfurization process comprising the steps of: 
 (a) contacting a hydrocarbon-containing fluid stream with finely divided solid sorbent particulates comprising a reduced-valence promoter metal component and zinc oxide in a fluidized bed reactor vessel under desulfurization conditions sufficient to remove sulfur from said hydrocarbon-containing fluid stream and convert at least a portion of said zinc oxide to zinc sulfide, thereby providing a desulfurized hydrocarbon-containing stream and sulfur-loaded sorbent particulates;    (b) simultaneously with step (a), contacting at least a portion of said hydrocarbon-containing stream and said sorbent particulates with a series of substantially horizontal, vertically spaced, cross-hatched baffle groups, thereby reducing axial dispersion in said fluidized bed reactor and enhancing sulfur removal from said hydrocarbon-containing fluid stream;    (c) contacting said sulfur-loaded sorbent particulates with an oxygen-containing regeneration stream in a regenerator vessel under regeneration conditions sufficient to convert at least a portion of said zinc sulfide to zinc oxide, thereby providing regenerated sorbent particulates comprising an unreduced promoter metal component; and (d) contacting said regenerated sorbent particulates with a hydrogen-containing reducing stream in a reducer vessel under reducing conditions sufficient to reduce said unreduced promoter metal component, thereby providing reduced sorbent particulates.    
     
     
         46 . A desulfurization process in accordance with  claim 45 , further comprising the step of: 
 (e) contacting said reduced sorbent particulates with said hydrocarbon-containing fluid stream in said fluidized bed reactor vessel under said desulfurization conditions.    
     
     
         47 . A desulfurization process in accordance with  claim 45 , wherein said hydrocarbon-containing fluid stream comprises hydrocarbons which are normally in a liquid state at standard temperature and pressure.  
     
     
         48 . A desulfurization process in accordance with  claim 47 , wherein said hydrocarbon-containing fluid stream has a hydrogen to hydrocarbon molar ratio in the range of from about 0.1:1 to about 3:1.  
     
     
         49 . A desulfurization process in accordance with  claim 48 , wherein said hydrocarbon-containing fluid stream comprises a hydrocarbon selected from the group consisting of gasoline, cracked-gasoline, diesel fuel, and mixtures thereof.  
     
     
         50 . A desulfurization process in accordance with  claim 45 , wherein said reduced-valence promoter component comprises a promoter metal selected from the consisting of nickel, cobalt, iron, manganese, tungsten, silver, gold, copper, platinum, zinc, ruthenium, molybdenum, antimony, vanadium, iridium, chromium, and palladium.  
     
     
         51 . A desulfurization process in accordance with  claim 45 , wherein said reduced-valence promoter component comprises nickel.  
     
     
         52 . A desulfurization process in accordance with  claim 45 , wherein each of said baffle groups has an open area in the range of from about 40 percent to about 90 percent of the cross-sectional area of said reactor vessel at the vertical location of that respective baffle group.  
     
     
         53 . A desulfurization process in accordance with  claim 52 , wherein said series of baffle groups comprises in the range of 3 to 7 individual baffle groups.  
     
     
         54 . A desulfurization process in accordance with  claim 53 , wherein the vertical spacing between adjacent ones of said individual baffle groups is in the range of from about 0.5 to about 6 feet.  
     
     
         55 . A desulfurization process in accordance with  claim 54 , wherein each of said individual baffle groups comprises a plurality of laterally spaced substantially cylindrical bars or tubes.