Production of diesel fuel from renewable feedstocks containing phosphorus

Abstract

A process has been developed for producing diesel fuel from renewable feedstocks such as plant oils, animal oils and greases. The process involves treating a renewable feedstock by hydrogenating and deoxygenating to provide a diesel boiling range fuel hydrocarbon product. If desired, the hydrocarbon product can be isomerized to improve cold flow properties. A portion of the hydrocarbon product is recycled to the treatment zone to increase the hydrogen solubility of the reaction mixture. The renewable feedstock comprises from about 1 to about 20 wt. ppm phosphorus measured as elemental phosphorus.

1 ) A process for producing a diesel boiling range hydrocarbon product from a renewable feedstock comprising;
 a) treating the renewable feedstock in a reaction zone by hydrogenating and deoxygenating the feedstock at reaction conditions to provide a reaction product comprising paraffins having from about 8 to about 24 carbon atoms, and recycling a portion of the reaction product to the reaction zone wherein the volume ratio of recycle to feedstock is in the range of about 2:1 to about 8:1, wherein the renewable feedstock comprises from about 1 to about 20 wt. ppm phosphorus, measured as to elemental phosphorus; and   b) isomerizing at least a portion of the paraffins in the reaction product in an isomerization zone by contacting with an isomerization catalyst at isomerization conditions to isomerize at least a portion of the paraffins to branched-paraffins.   
     
     
         2 ) The process of  claim 1  wherein the renewable feedstock comprises from about 10 to about 20 wt. ppm phosphorus, measured as elemental phosphorus. 
     
     
         3 ) The process of  claim 1  wherein the volume ratio of recycle to feedstock is in the range of about 2:1 to about 6:1. 
     
     
         4 ) The process of  claim 1  wherein the volume ratio of recycle to feedstock is in the range of about 4:1. 
     
     
         5 ) The process of  claim 1  further comprising pre-treating the renewable feedstock in a pretreatment zone at pretreatment conditions to remove phosphorus in excess of about 20 wt. ppm, measured as elemental phosphorus. 
     
     
         6 ) The process of  claim 1  where the feedstock is hydrogenated and deoxygenated by contacting the feedstock with a hydrogenation and deoxygenation catalyst at a temperature of about 200° C. to about 300° C. and a pressure of about 1379 kPa absolute (200 psia) to about 4826 kPa absolute (700 psia). 
     
     
         7 ) The process of  claim 1  wherein the reaction product is passed to the isomerization zone without employing phosphorus removal techniques. 
     
     
         8 ) The process of  claim 1  where deoxygenation comprises at least one of decarboxylation, decarbonylation, and hydrodeoxygenation. 
     
     
         9 ) The process of  claim 1  further comprising treating a petroleum hydrocarbon feedstock in the reaction zone. 
     
     
         10 ) The process of  claim 1  wherein the renewable feedstock comprises at least one component selected from the group consisting of canola oil, corn oil, soy oil, rapeseed oil, soybean oil, colza oil, tall oil, sunflower oil, hempseed oil, olive oil, linseed oil, coconut oil, castor oil, peanut oil, palm oil, mustard oil, cottonseed oil, jatropha oil, tallow, yellow and brown greases, lard, train oil, fats in milk, fish oil, algal oil, sewage sludge. 
     
     
         11 ) The process of  claim 10  wherein the renewable feedstock further comprises at least one co-feed component selected from the group consisting of spent motor oils, spent industrial to lubricants, used paraffin waxes, liquids derived from the gasification of coal, biomass, natural gas followed by a downstream liquefaction step, liquids derived from depolymerization, thermal or chemical, of waste plastics, and synthetic oils generated as byproducts from petrochemical and chemical processes.