Synthetic lubricant basestock and an integrated fischer-tropsch process for its production

Abstract

An integrated Fischer-Tropsch process for production of a synthetic lubricant basestock incorporating light Fischer-Tropsch products by oligomerizing such light Fischer-Tropsch products is provided. Synthetic lubricant basestock produced by an integrated Fischer-Tropsch process is also provided.

1 . An integrated Fischer-Tropsch process comprising the steps of: 
 (a) producing a synthetic crude by Fischer-Tropsch reaction of synthesis gas;    (b) fractionating the synthetic crude at least into a light Fischer Tropsch liquid, and a heavy Fischer Tropsch liquid wherein the light Fischer-Tropsch liquid comprises alcohols;    (c) contacting at least a part of the light Fischer Tropsch liquid with a dehydration catalyst to dehydrate alcohols in the light Fischer Tropsch liquid to corresponding alpha- and internal-olefins to form a dehydrated product;    (d) oligomerizing in an oligomerization reactor all or part of the dehydrated product produced in step (c) to form a product comprising a heavy branched olefin stream;    (e) hydroprocessing the heavy Fischer-Tropsch liquid to form a heavy crude baseoil; and    (f) introducing the heavy branched olefin stream and crude baseoil into a hydrofinisher to produce a synthetic lubricant crude basestock.    
     
     
         2 . The process of  claim 1  wherein the hydroprocessing step (e) comprises the steps of: 
 (e1) hydrocracking the HFTL;    (e2) hydrodewaxing all or part of the hydrocracked HFTL; and    (e3) fractionating the product of (e2) to recover a heavy crude baseoil.    
     
     
         3 . The process of  claim 1  wherein the hydroprocessing step (e) comprises the steps of: 
 (e4) hydrotreating the HFTL to form a hydrotreated HFTL;    (e5) hydrocracking the hydrotreated HFTL;    (e6) hydrodewaxing all or part of the product of (e5); and    (e7) fractionating the product of (e6) to recover a heavy crude baseoil.    
     
     
         4 . The process of  claim 1  wherein the hydroprocessing step (e) comprises the steps of: 
 (e8) hydrocracking the HFTL to form a hydrocracked HFTL;    (e9) fractionating the hydrocracked HFTL to recover a lighter and a heavier fraction;    (e10) recycling a portion of the heavier fraction from step (e9) into the hydrocracker of step (e8); and    (e11) hydrodewaxing the hydrocracked heavier fraction from step (e10).    
     
     
         5 . The process of  claim 1  wherein the dehydrated light Fischer-Tropsch liquid produced in step (c) is fractionated to recover a C 9 -C 18  fraction and wherein the C 9 -C 18  fraction is oligomerized in step (d).  
     
     
         6 . The process of  claim 1  wherein the oligomerization of step (d) is catalyzed by a BF 3 /co-catalyst system.  
     
     
         7 . The process of  claim 6  wherein the co-catalyst is an oxygen containing compound.  
     
     
         8 . The process of  claim 7  wherein the co-catalyst is selected from the group of mono-alcohols, glycol ethers, and polyglycol ethers.  
     
     
         9 . The process of  claim 1  wherein the oligomerization of step (d) occurs at temperatures from about 50° to about 300° F.  
     
     
         10 . The process of  claim 6  wherein the BF 3  is present in an amount from about 10 to about 150 parts per one-thousand parts of reactant by weight and the co-catalyst is present in an amount from about 10 to about 200 parts per one-thousand parts of reactant by weight.  
     
     
         11 . The process of  claim 1  wherein the oligomerization of step (d) is catalyzed by a catalyst system selected from the group of AlCl 3 /co-catalyst, H 3 PO 4 , and solid acidic resin catalysts.  
     
     
         12 . The process of  claim 1  wherein the dehydrated product of step (c) is fractionated to recover a C 9 -C 13  fraction and wherein the C 9 -C 13  fraction is the dehydrated light Fischer-Tropsch liquid used in step (d).  
     
     
         13 . The process of  claim 1  wherein the dehydrated light, Fischer-Tropsch liquid produced in step (c) is fractionated to recover a C 14 -C 18  fraction and wherein the C 14 -C 18  fraction is oligomerized in step (d).  
     
     
         14 . The process of  claim 1  further comprising the step of isomerizing at least a part of the dehydrated product of step (c) prior to oligomerization in step (d).  
     
     
         15 . The process of  claim 1  wherein the synthesis gas is produced by autothermal reaction in the presence of nitrogen.  
     
     
         16 . The process of  claim 1  wherein the dehydration catalyst is selected from the group of treated activated alumina and treated activated silica-alumina.  
     
     
         17 . The process of  claim 1  further comprising the steps of: 
 (g) fractionating the product of step (d) to isolate a nonoligomerized olefin/paraffin stream; and    (h) dehydrogenating the nonoligomerized olefin/paraffin stream by contacting it with a dehydrogenation catalyst.    
     
     
         18 . The process of  claim 17  wherein the dehydrogenation catalyst comprises a Group VIII metal supported on a high-surface inorganic support.  
     
     
         19 . The process of  claim 17  further comprising the step of: 
 (i) passing the product of step (h) into the oligomerization reactor.    
     
     
         20 . The process of  claim 1  further comprising the step of fractionating the synthetic lubricant crude basestock to recover a synthetic lubricant basestock product containing essentially no unsaturated hydrocarbons and essentially no hydrocarbons having a carbon number of less than 15.  
     
     
         21 . An integrated Fischer-Tropsch process comprising the steps of: 
 (a) producing a synthetic crude by Fischer-Tropsch reaction) of synthesis gas;    (b) fractionating the synthetic crude at least into a light Fischer Tropsch liquid, and a heavy Fischer Tropsch liquid wherein the light Fischer-Tropsch liquid comprises alcohols;    (c) subjecting at least some of the light Fischer-Tropsch liquid to means for dehydrogenating hydrocarbons to produce a dehydrogenated light Fischer-Tropsch liquid;    (d) oligomerizing in an oligomerization reactor at least a portion of the dehydrogenated light Fischer-Tropsch liquid to form a product comprising a heavy branched olefin stream;    (e) hydroprocessing the heavy Fischer-Tropsch liquid to form a heavy crude baseoil; and    (f) introducing the heavy branched olefin stream and heavy crude baseoil into a hydrofinisher to produce a synthetic lubricant crude basestock.    
     
     
         22 . The process of  claim 21  wherein the hydroprocessing step (e) comprises the steps of: 
 (e1) hydrocracking the HFTL;    (e2) hydrodewaxing all or part of the hydrocracked HFTL; and    (e3) fractionating the product of (e2) to recover a heavy crude baseoil.    
     
     
         23 . The process of  claim 21  wherein the hydroprocessing step (e) comprises the steps of: 
 (e4) hydrotreating the HFTL;    (e5) hydrocracking the hydrotreated HFTL;    (e6) hydrodewaxing all or part of the product of (e5); and    (e7) fractionating the product of (e6) to recover a heavy crude baseoil.    
     
     
         24 . The process of  claim 21  wherein the hydroprocessing step (e) comprises the steps of: 
 (e8) hydrocracking the HFTL;    (e9) fractionating the hydrocracked HFTL to recover a heavy crude baseoil and a heavier fraction;    (e10) recycling a portion of the heavier fraction from step (e9) into the hydrocracker of step (e8); and    (e11) hydrodewaxing the hydrocracked heavier fraction from step (e10).    
     
     
         25 . The process of  claim 21  wherein the dehydrated light Fischer-Tropsch liquid produced in step (c) is fractionated to recover a C 9 -C 18  fraction and wherein the C 9 -C 18  fraction is oligomerized in step (d).  
     
     
         26 . The process of  claim 21  wherein the oligomerization of step (d) is catalyzed by a BF 3 /co-catalyst system.  
     
     
         27 . The process of  claim 26  wherein the co-catalyst is an oxygen containing compound.  
     
     
         28 . The process of  claim 27  wherein the co-catalyst is selected from the group of mono-alcohols, glycol ethers, and polyglycol ethers.  
     
     
         29 . The process of  claim 21  wherein the oligomerization of step (d) occurs at temperatures from about 50° to about 300° F.  
     
     
         30 . The process of  claim 26  wherein the BF 3  is present in an amount from about 10 to about 150 parts per one-thousand parts of reactant by weight and the co-catalyst is present in an amount from about 10 to about 200 parts per one-thousand parts of reactant by weight.  
     
     
         31 . The process of  claim 21  wherein the oligomerization of step (d) is catalyzed by a catalyst system selected from the group of AlCl 3 /co-catalyst, H 3 PO 4 , and solid acidic resin catalysts.  
     
     
         32 . The process of  claim 21  further comprising the steps of: 
 (g) contacting at least a part of the light Fischer Tropsch liquid with a dehydration catalyst to dehydrate alcohols in the light Fischer Tropsch liquid to corresponding alpha- and internal-olefins to form a dehydrated product; and    (h) oligomerizing in the oligomerization reactor at least a portion of the dehydrated product produced in step (g) to form a product comprising a heavy branched olefin stream.    
     
     
         33 . The process of  claim 32  wherein the dehydration catalyst is selected from the group of treated activated alumina and treated activated silica-alumina.  
     
     
         34 . The process of  claim 32  wherein the dehydrated product of step (g) is fractionated to recover a C 9 -C 13  fraction and wherein the C 9 -C 13  fraction is the dehydrated light Fischer-Tropsch liquid used in step (d).  
     
     
         35 . The process of  claim 32  wherein the dehydrated product produced in step (g) is fractionated to recover a C 14 -C 18  fraction and wherein the C 14 -C 18  fraction is oligomerized in step (d).  
     
     
         36 . The process of  claim 32  further comprising the step of isomerizing at least a part of the dehydrated product of step (c) prior to oligomerization in step (d).  
     
     
         37 . The process of  claim 21  further comprising the steps of: 
 (i) fractionating the product of step (d) to isolate a nonoligomerized olefin/paraffin stream; and    (j) dehydrogenating the nonoligomerized olefin/paraffin stream by contacting it with a dehydration catalyst.    
     
     
         38 . The process of  claim 37  wherein the dehydrogenation catalyst is platinum supported on a high-surface alumina.  
     
     
         39 . The process of  claim 37  further comprising the step of: 
 (k) passing the product of step (j) into the oligomerization reactor.    
     
     
         40 . The process of  claim 21  further comprising the step of fractionating the synthetic lubricant crude basestock to recover a synthetic lubricant basestock product containing essentially no unsaturated hydrocarbons and essentially no hydrocarbons having a carbon number of less than 15.  
     
     
         41 . The process of  claim 1  wherein the synthesis gas is produced by autothermal reaction in the presence of nitrogen.  
     
     
         42 . A high stability synthetic lubricant crude basestock produced by the process of  claim 1  having a BI of between about 23.4% and about 25.5% and a DM of between about 18% and about 21.2% such that DM≧2BI−29.9.  
     
     
         43 . The high stability synthetic lubricant crude basestock produced by the process of  claim 1  wherein the BI is between about 23.4% and 24.7% and the DM is between about 20.4% and about 21.2%.  
     
     
         44 . The high stability synthetic lubricant crude basestock of  claim 43  wherein the BI is about 24.4% and the DM is about 21.1%  
     
     
         45 . A high stability synthetic lubricant crude basestock produced by the process of  claim 1  having a BI of 25.5% or less and DM of 21.2% or lower such that DM≧2BI−29.9.  
     
     
         46 . A high stability synthetic lubricant crude basestock produced by the process of  claim 21  having a BI of 25.5% or less and DM of 21.2% or lower such that DM≧2BI−29.9.  
     
     
         47 . A high stability synthetic lubricant crude basestock produced by the process of  claim 21  having a BI of between about 23.4% and about 25.5% and a DM of between about 18% and about 21.2% such that DM≧2BI−29.9.  
     
     
         48 . The high stability synthetic lubricant crude basestock produced by the process of  claim 21  wherein the BI is between about 23.4% and 24.7% and the DM is between about 20.4% and about 21.2%.  
     
     
         49 . The high stability synthetic lubricant crude basestock of  claim 48  wherein the BI is about 24.4% and the DM is about 21.1%  
     
     
         50 . A lubricant baseoil composition produced by an integrated Fischer-Tropsch process comprising at least 40% of methyl branched hydrocarbons, characterized by BI of between about 23.4% and about 25.5% and a DM of between about 18% and about 25.5% and at least 5% long-chain branched hydrocarbons wherein the branches have a carbon number of at least 2, and are characterized by BI of less than about 24% and a DM of less than about 21%, wherein the lubricant baseoil arises from both Fischer-Tropsch oil and Fischer-Tropsch wax.  
     
     
         51 . The lubricant baseoil composition of  claim 50  wherein the methyl branched hydrocarbons are characterized by a BI of about 25% and a DM of about 20%.  
     
     
         52 . The lubricant baseoil composition of  claim 50  wherein the long-chain branched hydrocarbons are characterized by a BI of about 21% and a DM of about 19%.  
     
     
         53 . A lubricant baseoil composition produced by an integrated Fischer-Tropsch process comprising at least about 40% of methyl branched hydrocarbons with a pour point of at most −10° C., and at least about 5% long chain branched hydrocarbons having a pour point equal to or less than −30° C.  
     
     
         54 . A lubricant baseoil composition produced by an integrated Fischer-Tropsch process comprising at least about 40% of methyl branched hydrocarbons and at least about 5% long chain branched hydrocarbons wherein the baseoil composition has a pour point of about −20° C.  
     
     
         55 . The process of  claim 1  further comprising the step of fractionating the synthetic lubricant crude basestock.  
     
     
         56 . A synthetic lubricant crude basestock produced by the process of  claim 1  which comprises between about 15 and about 25 vol % 2 cSt product, between about 15 and about 25 vol % 3 cSt product, between about 20 and about 30 vol % 5 cSt product, between about 20 and about 30 vol % 6 cSt product and between about 12 and about 18 vol % product having a viscosity of greater than 6 cSt.  
     
     
         57 . A synthetic lubricant crude basestock produced by the process of  claim 1  wherein 4 cSt and heavier products comprise at least 40% of the total lubricant crude basestock.  
     
     
         58 . A synthetic lubricant crude basestock produced by the process of  claim 21  which comprises between about 15 and about 25 vol % 2 cSt product, between about 15 and about 25 vol % 3 cSt product, between about 20 and about 30 vol % 5 cSt product, between about 20 and about 30 vol % 6 cSt product and between about 12 and about 18 vol % product having a viscosity of greater than 6 cSt.  
     
     
         59 . A synthetic lubricant crude basestock produced by the process of  claim 21  wherein 4 cSt and heavier products comprise at least 40% of the total lubricant crude basestock.  
     
     
         60 . The process of  claim 1  wherein the lubricant crude basestock comprises 2 cSt, 3 cSt, 4 cSt, and higher cSt components and wherein the ratio of 2 cSt plus 3 cSt component to 4 cSt and higher cSt components is between about 0.8 and about 1.2.  
     
     
         61 . The process of  claim 18  wherein the Group VIII metal is palladium.  
     
     
         62 . The process of  claim 18  wherein the Group VIII metal is nickel.  
     
     
         63 . The process of  claim 18  wherein the high-surface inorganic support is high-surface alumina.  
     
     
         64 . The process of  claim 18  wherein the Group VIII metal is palladium and the high-surface inorganic support is high-surface alumina.