Renewable diesel
The present technology relates to hydrocarbon fuels comprising renewable content. More particularly, the technology relates to manufacture of renewable diesel for potential use as aviation turbine fuel blendstock.
1. A process for producing a renewable diesel overhead fraction comprising the steps of
a. subjecting a feedstock comprising free fatty acids, mono-, di-, and/or tri-glycerides to hydrodeoxygenation (HDO) to produce an HDO effluent comprising C 14 -C 18 n-paraffins;
b. subjecting the HDO effluent to hydroisomerization to produce a hydroisomerizate comprising C 14 -C 18 isoparaffins and unreacted C 14 -C 18 n-paraffins; and
c. separating the hydroisomerizate in a flash drum into an overhead renewable diesel fraction and a bottoms fraction wherein both fractions comprise C 14 -C 18 n-paraffins and C 14 -C 18 isoparaffins;
wherein the overhead renewable diesel has a difference of 20° C. or less between its final boiling point (FBP) and its 95% boil-off temperature (T95) according to ASTM D2887 simulated distillation test method;
wherein the overhead renewable diesel fraction has an existent gum value of 7 mg/100 mL or less according to ASTM D381; and
wherein the hydroisomerizate has a value of final boiling point minus 95% boil-off temperature (FBP-T95) that is greater than 30° C. as measured by ASTM D2887 simulated distillation test method.
2. The process of claim 1 , wherein the overhead renewable diesel fraction comprises at least 90% C 14 -C 18 n-paraffins and iso-paraffins.
3. The process of claim 1 , wherein the overhead renewable diesel fraction is used as jet fuel blendstock.
4. The process of claim 1 , wherein the feedstock comprises tallow, lard, poultry fat, fish oil, canola oil, rapeseed oil, palm oil, soybean oil, corn oil, jatropha oil, carinata oil, cotton seed oil, hempseed oil, sunflower oil, greases from restaurants and/or food processing operations, microbial oil, or a combination of any two or more thereof.
5. The process of claim 1 , wherein the cloud point of the overhead renewable diesel fraction is less than −5° C.
6. The process of claim 5 , wherein the cloud point of the overhead renewable diesel fraction is between −12° C. and −30° C.
7. The process of claim 1 , wherein the hydrodeoxygenation is performed under at least 500 psia hydrogen partial pressure at temperatures in the 500-700° F. range over a sulfided molybdenum catalyst promoted by nickel and/or cobalt.
8. The process of claim 1 , wherein the hydroisomerization is performed under at least 500 psia hydrogen partial pressure at temperatures in the 580-680° F. range over a bifunctional catalyst comprising platinum or tungsten and a support comprising silica.
9. The process of claim 1 , wherein the feedstock is diluted with a hydrocarbon solvent.
10. The process of claim 9 , wherein the hydrocarbon solvent is a petroleum middle distillate.