Method for production of aviation fuel
A process plant and a process for production of a hydrocarbon suitable for use as jet fuel from a feedstock being a renewable feedstock or an oxygenate feedstock, including combining the renewable feedstock with an amount of a hydrocracked intermediate product, directing it to contact a material catalytically active in hydrodeoxygenation under hydrodeoxygenation conditions to provide a hydrodeoxygenated intermediate product, fractionating the hydrodeoxygenated intermediate product in at least two fractions including a first fraction of which at least 90% boils below a defined boiling point and a second fraction of which at least 90% boils above the defined boiling point, directing at least an amount of the second fraction to contact a material catalytically active in hydrocracking under hydrocracking conditions to provide the hydrocracked intermediate product, the process being suited for efficiently converting the upper-boiling point of an oxygenate feedstock such as a renewable feedstocks to a lower boiling product.
1. A process for production of a hydrocarbon fraction suitable for use as jet fuel from an oxygenate feedstock, comprising the steps of:
a. feeding the oxygenate feedstock to the process,
b. combining all of the fed feedstock with a hydrocracked intermediate product to form a combined feedstock, directing the combined feedstock to contact a material catalytically active in hydrodeoxygenation (HDO) under hydrodeoxygenation conditions to provide a hydrodeoxygenated intermediate product,
c. defining a fractionation boiling point, fractionating said hydrodeoxygenated intermediate product in at least two hydrocarbon liquid fractions, including a first fraction of which at least 90% boils below said defined boiling point and a second fraction of which at least 90% boils above said defined fractionation boiling point,
d. directing at least an amount of said second fraction to contact a material catalytically active in hydrocracking (HDC) under hydrocracking conditions to provide the hydrocracked intermediate product, wherein an entirety of the hydrocracked intermediate product is combined with the oxygenate feedstock of step (a),
wherein the process excludes the first fraction of step (c) and the oxygenate feedstock of step (a) from being directed to contact any material catalytically active in hydrocracking (HDC) under hydrocracking conditions to provide the hydrocracked intermediate product.
2. The process according to claim 1 wherein step (b) comprises separating hydrodeoxygenated intermediate product according to boiling point, to provide a hydrocracked intermediate jet product having T10 above 205° C. and final boiling point below 310° C. according to ASTM D86.
3. The process according to claim 1 , wherein the total volume of hydrogen sulfide relative to the volume of molecular hydrogen in the gas phase of the total stream directed to contact the material catalytically active in hydrodeoxygenation is at least 50 ppm v , optionally originating from an added stream comprising one or more sulfur compounds.
4. The process according to claim 1 , wherein said oxygenate feedstock comprises at least 50% wt triglycerides or fatty acids.
5. The process according to claim 1 , wherein hydrodeoxygenation conditions involve a temperature in the interval 250-400° C., a pressure in the interval 30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval 0.1-2 and wherein the material catalytically active in hydrodeoxygenation comprises molybdenum or optionally tungsten, optionally in combination with nickel and/or cobalt, supported on a carrier comprising one or more refractory oxides.
6. The process according to claim 1 , wherein hydrocracking conditions involve a temperature in the interval 250-400° C., a pressure in the interval 30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-4, optionally together with intermediate cooling by quenching with cold hydrogen, feed or product and wherein the material catalytically active in hydrocracking comprises (a) one or more active metals taken from the group platinum, palladium, nickel, cobalt, tungsten and molybdenum, (b) an acidic support taken from the group of a molecular sieve showing high cracking activity, and having a topology of MFI, BEA and FAU and amorphous acidic oxides and (c) a refractory support.
7. The process according to claim 1 , wherein the process conditions are selected such that the conversion, defined as the difference in the amount of material boiling above 310° C. in said hydrocracked intermediate product and the amount of material boiling above 310° C. in said second fraction, relative to the amount of material boiling above 310° C. in said second fraction, is above 20%.
8. The process according to claim 1 , wherein at least an amount of said first fraction is directed to contact a material catalytically active in hydrodearomatization (HDA) under hydrodearomatization conditions to provide a hydrodearomatized product comprising less than 1 wt/wt %, calculated by total mass of aromatic molecules relative to all hydrocarbons in the stream.
9. The process according to claim 8 , wherein hydrodearomatization conditions involve a temperature in the interval 200-350° C., a pressure in the interval 20-100 Bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8 and wherein said material catalytically active in hydrodearomatization comprises an active metal taken from the group comprising platinum, palladium, nickel, cobalt, tungsten and molybdenum, and a refractory support.
10. The process according to claim 8 wherein a hydrogen rich stream comprising at least 90 vol/vol % hydrogen is directed to contact the material catalytically active in hydrodearomatization (HDA).
11. The process according to claim 1 , wherein at least an amount of said first fraction is directed to contact a material catalytically active in isomerization (ISOM) under isomerization conditions.
12. The process according to claim 11 , wherein isomerization conditions involves a temperature in the interval 250-350° C., a pressure in the interval 20-100 Bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8 and wherein the material catalytically active in isomerization comprises an active metal taken from the group comprising platinum, palladium, nickel, cobalt, tungsten and molybdenum, an acidic support, and an amorphous refractory support comprising one or more oxides taken from the group comprising alumina, silica and titania.
13. The process according to claim 8 , wherein the hydrodearomatized product is directed to a gas/liquid separator (SEP 4 ) to provide a second stage gaseous fraction and a treated intermediate jet product which is directed to a further means of separation (STAB), to provide said hydrocarbon fraction suitable for use as a jet fuel and a treated product off gas.
14. The process according to claim 8 , wherein at least an amount of said hydrodearomatized product is directed to contact a material catalytically active in isomerization (ISOM) under isomerization conditions.
15. The process according to claim 14 , wherein isomerization conditions involves a temperature in the interval 250-350° C., a pressure in the interval 20-100 Bar, and a liquid hourly space velocity (LHSV) in the interval 0.5-8 and wherein the material catalytically active in isomerization comprises an active metal taken from the group comprising platinum, palladium, nickel, cobalt, tungsten and molybdenum, an acidic support, and an amorphous refractory support comprising one or more oxides taken from the group comprising alumina, silica and titania.