Process for improving cold flow properties and increasing yield of middle distillate feedstock through liquid full hydrotreating and dewaxing
Novel liquid-full process for improving cold flow properties and increasing yield of middle distillate fuel feedstock by hydrotreating and dewaxing the feedstock in liquid-full reactors.
1. A liquid-full process for hydroprocessing a middle distillate fuel feedstock, comprising:
(a) contacting the feedstock with (i) a diluent and (ii) hydrogen, to produce a feedstock/diluent/hydrogen mixture, wherein the hydrogen is dissolved in the mixture to provide a liquid feed;
(b) contacting the feedstock/diluent/hydrogen mixture with a hydrotreating catalyst in a first reaction zone, to produce a first product effluent; and
(c) contacting the first product effluent with a dewaxing catalyst in a second reaction zone, to produce a second product effluent comprising naphtha and a middle distillate product;
wherein the middle distillate product has at least one improved cold flow property compared to the middle distillate fuel feedstock and has the yield of at least 85 wt %, and wherein the middle distillate fuel feedstock comprises a range of products from the middle fraction of a crude oil barrel.
2. The process of claim 1 , wherein the middle distillate fuel feedstock has a nitrogen content of at least 200wppm, and the middle distillate product has a cloud point of at least 15° C. lower compared to the middle distillate fuel feedstock.
3. The process of claim 1 , wherein the middle distillate fuel feedstock has a nitrogen content of at least 90 wppm, and the middle distillate product has a cloud point of at least 25° C. lower compared to the middle distillate fuel feedstock.
4. The process of claim 1 , wherein steps (b) and (c) are conducted in a single reactor containing one or more catalyst beds.
5. The process of claim 1 , wherein steps (b) and (c) are conducted in separate reactors, each of the reactors containing one or more catalyst beds.
6. The process of claim 1 , wherein the first product effluent includes H 2 S and NH 3 dissolved therein and is fed directly into the second reaction zone without separating ammonia, hydrogen sulfide and remaining hydrogen from the first product effluent.
7. The process of claim 1 , wherein the first reaction zone has a temperature in the range of about 225° C. to about 425° C. and a pressure in the range of about 3.0MPa to about 17.5MPa.
8. The process of claim 1 , wherein the second reaction zone has a temperature in the range of about 225° C. to about 425° C. and a pressure in the range of about 3.0MPa to about 17.5MPa.
9. The process of claim 1 , wherein both the middle distillate fuel feedstock and the middle distillate product are diesels.
10. The process of claim 1 , wherein the dewaxing catalyst is selected from the group consisting of catalysts comprising a non-precious metal and an oxide support, catalysts comprising a crystalline, microporous oxide structure without metal loaded on it, and catalysts comprising a molecular sieve without metal loaded on it.
11. The process of claim 1 , wherein the dewaxing catalyst comprises a zeolite.
12. The process of claim 1 , wherein the dewaxing catalyst comprises a crystalline, microporous oxide structure without metal loaded on it.
13. The process of claim 1 , wherein the dewaxing catalyst comprises a zeolite without metal loaded on it.
14. The process of claim 13 , wherein the zeolite has a 8-member ring structure, a 10-member ring structure, or a 12-member ring structure.
15. The process of claim 1 further comprising contacting the second product effluent with a hydrotreating catalyst in a third reaction zone to produce a third product effluent.
16. The process of claim 1 further comprising recovering the second product effluent.
17. The process of claim 1 further comprising recycling a portion of the second product effluent for use as all or part of the diluent.
18. The process of claim 1 , wherein the middle distillate fuel feedstock has a nitrogen content of at least 90wppm.