Systems and methods for producing fuel from a renewable feedstock

Abstract

Methods and systems are provided for producing a fuel from a renewable feedstock. The method includes deoxygenating the renewable feedstock with a hydrogenation catalyst in a deoxygenation reaction zone to produce normal paraffins. The normal paraffins are isomerized to form isomerized paraffins using an isomerization catalyst in an isomerization reaction zone. Aromatic compounds are formed from non-aromatic compounds with an aromatic catalyst in an aromatic production zone downstream from the deoxygenation reaction zone.

1 . A system for producing fuel from a renewable feedstock comprising:
 a renewable feedstock feed system;   a deoxygenation reaction zone comprising a hydrogenation catalyst, wherein the deoxygenation reaction zone is downstream from the renewable feedstock feed system;   an aromatic production zone comprising an aromatic catalyst, wherein the aromatic production zone is downstream from the deoxygenation reaction zone; and   an isomerization reaction zone comprising an isomerization catalyst, wherein the isomerization reaction zone is downstream from the deoxygenation reaction zone.   
     
     
         2 . The system of  claim 1  further comprising:
 an aromatics distillation column configured to produce an aromatics distillation column bottoms stream, wherein the aromatics distillation column is downstream from the aromatic production zone, and wherein the system is configured so that the aromatics distillation column bottoms stream flows to the isomerization reaction zone. 
 
     
     
         3 . The system of  claim 2  wherein the aromatics distillation column is configured to produce an aromatic compounds stream, and wherein the system is configured such that the aromatic compounds stream bypasses the isomerization reaction zone. 
     
     
         4 . The system of  claim 1  further comprising a hot liquid separator positioned downstream from the deoxygenation reaction zone. 
     
     
         5 . The system of  claim 1  wherein the aromatic production zone is downstream from the isomerization reaction zone. 
     
     
         6 . The system of  claim 5  further comprising an aromatics distillation column positioned downstream from the aromatic production zone. 
     
     
         7 . The system of  claim 1  further comprising a pretreatment zone downstream from the renewable feedstock feed system and upstream from the deoxygenation reaction zone. 
     
     
         8 . The system of  claim 1  further comprising a sulfiding agent feed system configured to add a sulfiding agent to the renewable feedstock prior to the deoxygenation reaction zone. 
     
     
         9 . A method of producing fuel from a renewable feedstock, the method comprising the steps of:
 deoxygenating the renewable feedstock in a deoxygenation reaction zone to produce normal paraffins;   isomerizing the normal paraffins in an isomerization reaction zone to produce isomerized paraffins;   forming aromatic compounds from non-aromatic compounds in an aromatic production zone, and wherein the aromatic production zone is downstream from the deoxygenation reaction zone.   
     
     
         10 . The method of  claim 9  further comprising:
 separating the aromatic compounds from the non-aromatic compounds downstream from the aromatic production zone; 
 feeding the non-aromatic compounds from the aromatic production zone into the isomerization reaction zone; and 
 combining the aromatic compounds with the isomerized paraffins downstream from the isomerization reaction zone. 
 
     
     
         11 . The method of  claim 9  wherein the step of deoxygenating the renewable feedstock further comprises deoxygenating the renewable feedstock with a hydrogenation catalyst, the method further comprising sulfiding the hydrogenation catalyst. 
     
     
         12 . The method of  claim 9  wherein forming aromatic compounds from non-aromatic compounds further comprises forming aromatic compounds from non-aromatic compounds downstream from the isomerization reaction zone. 
     
     
         13 . The method of  claim 9  wherein forming aromatic compounds from non-aromatic compounds further comprises forming aromatic compounds from non-aromatic compounds upstream from the isomerization reaction zone. 
     
     
         14 . The method of  claim 9  further comprising:
 removing gases from the non-aromatic compounds prior to forming the aromatic compounds. 
 
     
     
         15 . The method of  claim 9  further comprising:
 removing contaminants from the renewable feedstock in a pretreatment zone prior to deoxygenating the renewable feedstock. 
 
     
     
         16 . A method of producing fuel from a renewable feedstock, the method comprising the steps of:
 deoxygenating the renewable feedstock in a deoxygenation reaction zone to produce normal paraffins;   improving a cold flow property of the normal paraffins by forming aromatic compounds from normal paraffins.   
     
     
         17 . The method of  claim 16  wherein improving cold flow properties further comprises forming isomerized paraffins from the normal paraffins in an isomerization reaction zone downstream from the deoxygenation reaction zone. 
     
     
         18 . The method of  claim 17  further comprising:
 diverting the aromatic compounds around the isomerization reaction zone. 
 
     
     
         19 . The method of  claim 16  further comprising:
 sulfiding the hydrogenation catalyst. 
 
     
     
         20 . The method of  claim 16  further comprising:
 removing contaminants from the renewable feedstock in a pretreatment zone prior to deoxygenating the renewable feedstock.