Fischer-tropsch derived diesel fuel and process for making same

Abstract

The present invention is directed to a Fischer-Tropsch derived distillate suitable for use as a distillate fuel having a flash point 38° C. minimum measured by ASTM D 93 and a cloud point of +14° C. or less and further containing not less than 0.01 wt,% oxygen in each of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol and not more than 0.01 wt.% oxygen in C 11+ linear alcohols. Preferably, the Fischer-Tropsch derived distillate will have a cloud point at or below 0° C., and more preferably the cloud point of the Fischer-Tropsch derived distillate, will be at or below −15° C.

1 . A Fischer-Tropsch derived distillate suitable for use as a diesel fuel having a flash point 38° C. minimum measured by ASTM D 93 a cloud point of +14° C. or less and further containing not less than 0.01 wt. % oxygen in at least two alcohols selected from the group consisting of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol; and mixtures of more than two alcohols, and not more than 0.01 wt. % oxygen in C 11+  linear alcohols. 
     
     
         2 . The Fischer-Tropsch derived distillate of  claim 1  wherein the cloud point is 0° C. 
     
     
         3 . The Fischer-Tropsch derived distillate of  claim 2  wherein the cloud point is −15° C. or less. 
     
     
         4 . The Fischer-Tropsch derived distillate of  claim 3  wherein the cloud point is −25° C. or less. 
     
     
         5 . The Fischer-Tropsch derived distillate of  claim 4  wherein the cloud point is −49° C. or less. 
     
     
         6 . The Fischer-Tropsch derived distillate of  claim 1  wherein the sum of the oxygenate content of the C 5 -C 10  linear alcohols present are within the range of from 0.01 wt. % oxygen and 1 wt. % oxygen. 
     
     
         7 . A process for preparing a Fischer-Tropsch derived distillate fuel which comprises;
 (a) separating a Fischer-Tropsch condensate into a first and second fraction, wherein:
 (i) said first fraction comprises not less than 0.01 wt. % oxygen of alcohols selected from the group consisting of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and mixtures thereof, and not more than 0.01 wt. % oxygen in C 11+  linear alcohols and 
 (ii) said second fraction comprises C 11+  linear alcohols; 
   (b) removing the C 11+  linear alcohols from at least a portion of said second fraction and recovering a treated heavy fraction substantially free of C 11+  linear alcohols; and   (c) blending at least a portion of the first fraction of step a(i) and a portion of the treated heavy fraction of step (b) in the proper proportion to prepare a Fischer-Tropsch derived distillate fuel wherein the sum of the oxygenate content of the C 5 -C 10  alcohols present are within the range of from 0.01 wt. % oxygen and to 1 wt. % oxygen, the cloud point is not more than +14° C., and the flash point 38° C. minimum measured by ASTM D 93.   
     
     
         8 . The process of  claim 7  wherein the first fraction and the second fraction are blended in step (c) with the proper proportion to prepare a Fischer-Tropsch derived distillate fuel having a cloud point of not more than 0° C. 
     
     
         9 . The process of  claim 8  wherein the first fraction and the second fraction are blended in step (c) with the proper proportion to prepare a Fischer-Tropsch derived distillate fuel having a cloud point of not more than −15° C. 
     
     
         10 . The process of  claim 7  wherein the Fischer-Tropsch condensate is separated into first, second, and third fractions wherein said first and second fractions are as described and said third fraction comprises C 4−  linear alcohols. 
     
     
         11 . The process of  claim 7  wherein the second fraction is treated by a process selected from hydrotreating, hydrocracking, hydroisomerization, dehydration, adsorption, absorption, or a combination thereof to obtain the treated heavy fraction substantially free of C 11+  linear alcohols. 
     
     
         12 . In a distillate fuel having a cloud point of +14° C. or less, the improvement comprising not less than 0.01 wt. % oxygen in at least two alcohols selected from the group consisting of 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and mixtures of more than two alcohols; and not more than 0.01 wt. % oxygen in C11 +  linear alcohols. 
     
     
         13 . The distillate fuel of  claim 12  wherein the cloud point is 0° C. or less. 
     
     
         14 . The distillate fuel of  claim 13  wherein the cloud point is −15° C. or less. 
     
     
         15 . The distillate fuel of  claim 12  wherein the sum of the oxygenate content of the C 5 -C 10  linear alcohols present are within the range of from 0.01 wt. % oxygen and 1 wt. % oxygen. 
     
     
         16 . The diesel fuel of  claim 12  wherein the alcohol is any two of the C 5 -C 10  linear alcohols in a total concentration less than 1 wt. % oxygen. 
     
     
         17 . The Fischer-Tropsch derived distillate of  claim 1  wherein the alcohol is any two of the C 5 -C 10  linear alcohols in a total concentration less than 1 wt. % oxygen. 
     
     
         18 . The Fischer-Tropsch derived distillate of  claim 7  wherein the alcohol is any two of the C 5 -C 10  linear alcohols in a total concentration less than 1 wt. % oxygen. 
     
     
         20 . The Fischer-Tropsch derived distillate according to claim  19  with 1-alcohols selected from the groups consisting of C 5  and C 6 ; C 5  and C 7 ; or C 6  and C 7 . 
     
     
         21 . The process of  claim 7  wherein the first fraction further includes 1-alcohols C 8 , C 9  and C 10  and step b removes the C 11+  linear alcohols from at least a portion of said second fraction and recovering a treated heavy fraction substantially free of C 11+  linear alcohols and step (c) blends at least a portion of the first fraction of step a(i) and a portion of the treated heavy fraction of step (b). 
     
     
         22 . The diesel fuel of  claim 12  further comprising 1-alcohols selected from the group consisting of C 8 , C 9  and C 10  and mixtures thereof alcohols and wherein the paraffins are at least 90% i-paraffins. 
     
     
         23 . The diesel fuel of  claim 1  further comprising 1-alcohols selected from the group consisting of C 8 , C 9  and C 10  and mixtures thereof alcohols and wherein the paraffins are at least 90% i-paraffins.