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 in a deoxygenation zone to produce hydrocarbons with normal paraffins. The hydrocarbons with normal paraffins are isomerized to produce hydrocarbons with branched paraffins. The hydrocarbons with branched paraffins are fractionated to produce a naphtha at a naphtha outlet, where the naphtha is further isomerized.

1 . 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 hydrocarbons comprising normal paraffins;   isomerizing the hydrocarbons comprising normal paraffins to produce hydrocarbons comprising branched paraffins;   fractionating the hydrocarbons comprising branched paraffins to produce a naphtha at a naphtha outlet; and   isomerizing the naphtha from the naphtha outlet.   
     
     
         2 . The method of  claim 1  wherein isomerizing the hydrocarbons comprising normal paraffins further comprise isomerizing the hydrocarbons comprising normal paraffins in a first isomerization reaction zone at isomerization conditions; and wherein isomerizing the naphtha further comprises isomerizing the naphtha in the first isomerization reaction zone. 
     
     
         3 . The method of  claim 2  wherein isomerizing the naphtha further comprises adding the naphtha to the first isomerization reaction zone such that the naphtha bypasses a portion of an isomerization catalyst positioned within the first isomerization reaction zone. 
     
     
         4 . The method of  claim 2  wherein isomerizing the naphtha further comprises isomerizing the naphtha in a second isomerization reaction zone. 
     
     
         5 . The method of  claim 1  wherein isomerizing the naphtha further comprises isomerizing the naphtha in a second isomerization reaction zone. 
     
     
         6 . The method of  claim 1  wherein deoxygenating the renewable feedstock further comprises deoxygenating the renewable feedstock wherein the renewable feedstock comprises glycerides or free fatty acids. 
     
     
         7 . The method of  claim 1  wherein deoxygenating the renewable feedstock further comprises deoxygenating the renewable feedstock wherein the renewable feedstock comprises oil extracted from a plant or an animal. 
     
     
         8 . The method of  claim 1  further comprising sulfiding a deoxygenation catalyst in the deoxygenation reaction zone. 
     
     
         9 . The method of  claim 1  further comprising:
 contacting the renewable feedstock with a guard bed catalyst at pretreatment conditions. 
 
     
     
         10 . The method of  claim 1  further comprising:
 pre-cleaning the renewable feedstock in a pre-cleaning zone. 
 
     
     
         11 . A method of producing fuel from a renewable feedstock, the method comprising the steps of:
 contacting the renewable feedstock with a deoxygenation catalyst to produce hydrocarbons comprising normal paraffins;   contacting the hydrocarbons comprising normal paraffins with an isomerization catalyst to produce hydrocarbons comprising branched paraffins;   fractionating the hydrocarbons comprising branched paraffins to produce a naphtha at a naphtha outlet; and   isomerizing the naphtha from the naphtha outlet.   
     
     
         12 . The method of  claim 11  wherein contacting the hydrocarbons comprising normal paraffins with the isomerization catalyst further comprises contacting the hydrocarbons comprising normal paraffins with the isomerization catalyst wherein the isomerization catalyst is within a first isomerization reaction zone; and wherein isomerizing the naphtha further comprises contacting the naphtha with the isomerization catalyst in the first isomerization reaction zone. 
     
     
         13 . The method of  claim 12  wherein isomerizing the naphtha further comprises adding the naphtha to an isomerization reactor at a side inlet of the isomerization reactor, wherein the isomerization catalyst is positioned within the isomerization reactor and wherein the side inlet is positioned such that the naphtha bypasses some of the isomerization catalyst within the isomerization reactor. 
     
     
         14 . The method of  claim 12  wherein isomerizing the naphtha further comprises contacting the naphtha with the isomerization catalyst in a second isomerization reaction zone. 
     
     
         15 . The method of  claim 11  wherein contacting the hydrocarbons comprising normal paraffins with the isomerization catalyst further comprises contacting the hydrocarbons comprising normal paraffins with the isomerization catalyst wherein the isomerization catalyst is within a first isomerization reaction zone; and wherein isomerizing the naphtha further comprises isomerizing the naphtha in a second isomerization reaction zone different than the first isomerization reaction zone. 
     
     
         16 . The method of  claim 11  wherein contacting the renewable feedstock with the deoxygenation catalyst further comprises contacting the renewable feedstock with the deoxygenation catalyst wherein the renewable feedstock comprises glycerides or free fatty acids. 
     
     
         17 . The method of  claim 11  wherein contacting the renewable feedstock with the deoxygenation catalyst further comprises contacting the renewable feedstock with the deoxygenation catalyst wherein the renewable feedstock comprises oil extracted from a plant or an animal. 
     
     
         18 . The method of  claim 11  further comprising sulfiding the deoxygenation catalyst. 
     
     
         19 . The method of  claim 1  further comprising:
 pre-cleaning the renewable feedstock in a pre-cleaning zone. 
 
     
     
         20 . A system for producing fuel from a renewable feedstock comprising;
 a renewable feedstock feed system;   a deoxygenation reaction zone coupled to the renewable feedstock feed system;   a first isomerization reaction zone coupled to the deoxygenation reaction zone;   a fractionation zone coupled to the first isomerization reaction zone, wherein the fractionation zone comprises a naphtha outlet; and   an isomerization reactor, wherein the naphtha outlet is coupled to the isomerization reactor.