Methods and apparatuses for processing renewable feedstocks

Abstract

Embodiments of methods and apparatuses for processing a renewable feedstock are provided herein. In one example, a method comprises dividing a H 2 -rich make-up stream into a first H 2 -rich portion and a second H 2 -rich portion. The second H 2 -rich portion has a lower mass flow rate than the first H 2 -rich portion. The renewable feedstock is deoxygenated in the presence of the first H 2 -rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins. At least a portion of the deoxygenating reaction zone effluent is isomerized in the presence of the second H 2 -rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin. The isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.

What is claimed is: 
     
         1 . A method for processing a renewable feedstock, the method comprising the steps of:
 dividing a H 2 -rich make-up stream into a first H 2 -rich portion and a second H 2 -rich portion that has a lower mass flow rate than the first H 2 -rich portion;   deoxygenating the renewable feedstock in the presence of the first H 2 -rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins; and   isomerizing at least a portion of the deoxygenating reaction zone effluent in the presence of the second H 2 -rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin, wherein the isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.   
     
     
         2 . The method of  claim 1 , wherein the step of dividing comprises forming the first H 2 -rich portion having a first mass flow rate and the second H 2 -rich portion having a second mass flow rate that is about 75% or less of the first mass flow rate. 
     
     
         3 . The method of  claim 2 , wherein the step of dividing comprises forming the second H 2 -rich portion having the second mass flow rate that is from about 10 to about 75% of the first mass flow rate. 
     
     
         4 . The method of  claim 1 , wherein the step of isomerizing comprises isomerizing at least the portion of the deoxygenating reaction zone effluent at the first hydrogen partial pressure of from about 1,380 to about 3,450 kPa gauge. 
     
     
         5 . The method of  claim 1 , wherein the step of isomerizing comprises isomerizing at least the portion of the deoxygenating reaction zone effluent at the first hydrogen partial pressure of from about 1,380 to about 3,280 kPa gauge. 
     
     
         6 . The method of  claim 1 , wherein the step of deoxygenating comprises deoxygenating the renewable feedstock at a second hydrogen partial pressure that is substantially the same as the first hydrogen partial pressure. 
     
     
         7 . The method of  claim 1 , wherein the step of deoxygenating comprises deoxygenating the renewable feedstock at a second hydrogen partial pressure that is greater than the first hydrogen partial pressure. 
     
     
         8 . The method of  claim 7 , wherein the step of deoxygenating comprises deoxygenating the renewable feedstock at the second hydrogen partial pressure of about 4,140 kPa gauge or greater. 
     
     
         9 . The method of  claim 7 , wherein the step of deoxygenating comprises deoxygenating the renewable feedstock at the second hydrogen partial pressure of from about 4,140 to about 8,270 kPa gauge. 
     
     
         10 . A method for processing a renewable feedstock, the method comprising the steps of:
 separating H 2 , C 3   −  hydrocarbons, CO, CO 2 , NH 3 , H 2 S, and/or H 2 O from a deoxygenating reaction zone effluent that contains normal paraffins using a first H 2 -rich portion of a H 2 -rich make-up stream to form a liquid normal paraffin-containing stream;   fluidly communicating a second H 2 -rich portion of the H 2 -rich make-up stream to an isomerization reaction zone, wherein the second H 2 -rich portion has a lower mass flow rate than the first H 2 -rich portion; and   contacting the liquid normal paraffin-containing stream with an isomerization catalyst in the presence of the second H 2 -rich portion in the isomerization reaction zone that is operating at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin, wherein the isomerization conditions include a first hydrogen partial pressure of about 4,140 kPa gauge or less.   
     
     
         11 . The method of  claim 10 , wherein the step of separating comprises contacting at least a portion of the deoxygenating reaction zone effluent with the first H 2 -rich portion in an enhanced hot separator to remove H 2 , C 3   −  hydrocarbons, CO, CO 2 , NH 3 , H 2 S, and/or H 2 O and form the liquid normal paraffin-containing stream. 
     
     
         12 . The method of  claim 11 , wherein the step of contacting comprises contacting at least the portion of the deoxygenating reaction zone effluent with the first H 2 -rich portion in the enhanced hot separator at a temperature of from about 100 to about 350° C. 
     
     
         13 . The method of  claim 11 , wherein the step of separating comprises separating H 2 , C 3   −  hydrocarbons, CO, CO 2 , NH 3 , H 2 S, and/or H 2 O from the deoxygenating reaction zone effluent in a hot separator to form an intermediate liquid normal paraffin-containing stream, and wherein the step of contacting comprises contacting the intermediate liquid normal paraffin-containing stream with the first H 2 -rich portion in the enhanced hot separator to form the liquid normal paraffin-containing stream. 
     
     
         14 . The method of  claim 13 , wherein the step of separating comprises separating H 2 , C 3   −  hydrocarbons, CO, CO 2 , NH 3 , H 2 S, and/or H 2 O from the deoxygenating reaction zone effluent in the hot separator at a temperature of from about 100 to about 350° C. 
     
     
         15 . The method of  claim 13 , wherein the step of separating in the hot separator and contacting in the enhanced hot separator form a first vapor stream and a second vapor stream, respectively, each comprising H 2  and C 3   −  hydrocarbons, and wherein the method further comprises the steps of:
 combining the first and second vapor streams to form a combined H 2 —, C 3   −  hydrocarbon-containing stream; and 
 separating the combined H 2 —, C 3   −  hydrocarbon-containing stream in a cold separator to form a H 2 -rich stream that comprises the first H 2 -rich portion. 
 
     
     
         16 . The method of  claim 15 , further comprising the step of:
 deoxygenating the renewable feedstock in the presence of the H 2 -rich stream at hydroprocessing conditions effective to form the deoxygenating reaction zone effluent.   
     
     
         17 . The method of  claim 15 , wherein the step of separating the combined H 2 —, C 3   −  hydrocarbon-containing stream comprises separating the combined H 2 —, C 3   −  hydrocarbon-containing stream in the cold separator at a temperature of from about 20 to about 60° C. 
     
     
         18 . The method of  claim 10 , further comprising the step of:
 fluidly communicating the isomerization reaction zone effluent from the isomerization reaction zone to a product recovery zone for separating the isomerization reaction zone effluent into product streams.   
     
     
         19 . The method of  claim 10 , further comprising the steps of:
 separating H 2  from the isomerization reaction zone effluent to form a H 2 -rich stream and a liquid branched paraffin-containing stream; and   combining the H 2 -rich stream and the first H 2 -rich portion to form a combined H 2 -rich stream, and wherein the step of separating comprises separating H 2,  C 3   −  hydrocarbons, CO, CO 2 , NH 3 , H 2 S, and/or H 2 O from the deoxygenating reaction zone effluent using the combined H 2 -rich stream to form the liquid normal paraffin-containing stream.   
     
     
         20 . An apparatus for processing a renewable feedstock, the apparatus comprising:
 a control valve configured to divide a H 2 -rich make-up stream into a first H 2 -rich portion and a second H 2 -rich portion that has a lower mass flow rate than the first H 2 -rich portion;   a deoxygenating reaction zone containing a hydroprocessing catalyst and configured to deoxygenate the renewable feedstock in the presence of the first H 2 -rich portion at hydroprocessing conditions effective to form a deoxygenating reaction zone effluent that contains normal paraffins; and   an isomerization reaction zone containing an isomerization catalyst and configured to isomerize at least a portion of the deoxygenating reaction zone effluent in the presence of the second H 2 -rich portion at isomerization conditions effective to form an isomerization reaction zone effluent that contains branched paraffin, wherein the isomerization conditions include a hydrogen partial pressure of about 4,140 kPa gauge or less.