Processes for selective naphtha reforming

Patent metadata

Field	Value
Publication number	US-10465129-B2
Application number	US-201816106981-A
Country	US
Kind code	B2
Filing date	Aug 21, 2018
Priority date	Aug 23, 2017
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

Process for reforming a hydrocarbon feedstock comprising paraffins and naphthenes. A hydrocarbon feedstock is separated to produce a first fraction enriched in naphthenes and a second fraction that is enriched in paraffins. The first fraction is contacted with a first reforming catalyst in a first reactor that is maintained at a temperature and pressure that facilitates conversion of naphthenes to aromatics. The second fraction is contacted with a second reforming catalyst in a second reactor at a temperature and pressure that converts at least 50 wt. % of paraffins in the second fraction to olefins. The process produces a liquid hydrocarbon reformate product suitable for use as a blend component of a liquid transportation fuel.

First claim

We claim:

1. A process for reforming a hydrocarbon feedstock, comprising:
a) providing a hydrocarbon feedstock comprising paraffins and naphthenes, each of which comprises from four to twelve carbon atoms, wherein the boiling point range of the hydrocarbon feedstock ranges from −12° C. to 230° C.;
b) separating the hydrocarbon feedstock into a first fraction and a second fraction, wherein the first fraction is enriched in naphthenes relative to the hydrocarbon feedstock, and the second fraction is enriched in paraffins relative to the hydrocarbon feedstock;
c) contacting the first fraction with a first reforming catalyst to convert the first fraction to a first reformer effluent that is characterized by increased research octane number and that is suitable for use as a blend component of a liquid transportation fuel, wherein the contacting is conducted at a temperature, pressure and a hydrogen to hydrocarbon ratio that facilitates the catalytic aromatization of naphthenes present in the first fraction, thereby producing a first reformer effluent that comprises an increased wt. % of aromatics relative to the first fraction and that is characterized by an increased research octane number relative to the first fraction, wherein the temperature is maintained in the range of 480° C. or less to minimize cracking of naphthenes present in the first fraction, and aromatics present in the first reformer effluent;
d) combining the second fraction with a second reforming catalyst to facilitate conversion of paraffins present in the second fraction to produce a second reformer effluent suitable for use as a blend component of a liquid transportation fuel that predominantly comprises olefins containing four or five carbon atoms and unreacted paraffins and that is characterized by an increased research octane number relative to the second fraction, wherein the combining is conducted at a temperature, a pressure and a hydrogen to hydrocarbon ratio that facilitates the dehydrogenation of at least 50% of the paraffins present in the second fraction.

2. The process of claim 1 , wherein the first reforming catalyst comprises a solid support that comprises acidic sites, and the second reforming catalyst comprises a solid support that does not comprise acidic sites.

3. The process of claim 1 , wherein the first reforming catalyst is a bi-functional naphtha reforming catalyst comprising a solid support that is selected from zeolite, silica, alumina, chlorided alumina and fluorided alumina.

4. The process of claim 3 , wherein the first reforming catalyst further comprises at least one metal selected from Group VIIB, Group VIIIB, Group IIB, Group IIIA and Group IVA of the Periodic Table.

5. The process of claim 3 , wherein the first reforming catalyst further comprises at least one metal selected from Pt, Ir, Rh, Re, Sn, Ge and In.

6. The process of claim 1 , wherein the second reforming catalyst comprises a solid support comprising Group II aluminate spinels according to the formula M(AlO 2 ) 2 or MO.Al 2 O 3 , wherein M is a divalent Group IIA or Group IIB metal.

7. The process of claim 6 , wherein the second reforming catalyst further comprises at least one metal from Group VIIIB of the Periodic Table.

8. The process of claim 6 , wherein the second reforming catalyst further comprises at least one co-promoter selected from the group consisting of As, Sn, Pb, Ge and Group IA metals.

9. The process of claim 1 , wherein the catalytic activity of the first reforming catalyst is adversely affected by contact with steam, and the catalytic activity of the second reforming catalyst is not adversely affected by contact with steam.

10. The process of claim 1 , wherein the hydrocarbon feedstock comprises at least one of:
a refinery raffinate, hydrotreated straight run naphtha, coker naphtha, hydrocracker naphtha, hydrotreated hydrocracker naphtha, refinery hydrotreated heavy naphtha, refinery hydrotreated coker naphtha, or C4+ hydrocarbons derived from natural gas liquids.

11. The process of claim 1 , wherein the boiling point range of the hydrocarbon feedstock ranges from 27° C. to 230° C., comprising hydrocarbons that contain from five to twelve carbon atoms.

12. The process of claim 1 , wherein the contacting of c) is conducted at a temperature in the range from 470° C. to 480° C. to minimize cracking of naphthenes present in the first fraction, and aromatics present in the first reformer effluent.

13. The process of claim 1 , wherein the combining of d) is conducted at a temperature, a pressure and a hydrogen to hydrocarbon ratio that facilitates the dehydrogenation of at least 70% of the paraffins present in the second fraction.

14. The process of claim 1 , wherein a hydrogen to hydrocarbon ratio during the contacting of c) is greater than 2:1, and a hydrogen to hydrocarbon ratio during the combining of d) is equal to, or less than 1:1.

15. The process of claim 1 , wherein the hydrogen to hydrocarbon ratio during the contacting of c) is at least 4:1 and the hydrogen to hydrocarbon ratio during the combining of d) is equal to, or less than, 0.7:1.

16. The process of claim 1 , additionally comprising contacting the second reformer effluent with an oligomerization catalyst at a temperature and a pressure that facilitates the oligomerization of olefins in the effluent to larger hydrocarbons that are characterized by a decreased Reid vapor pressure, and that are suitable for use as a blend component of a liquid transportation fuel.

17. The process of claim 1 , wherein the second reforming catalyst additionally facilitates the aromatization of naphthenes present in the second fraction.

18. The process of claim 1 , wherein a supplemental feedstream of light paraffins comprising from four to five carbon atoms is added to the second fraction either prior to, or concurrent with the combining of the second fraction with the second reforming catalyst.

19. The process of claim 1 , additionally comprising separating the second reformer effluent to produce a light hydrocarbons fraction comprising hydrocarbons containing from one to four carbon atoms, and a heavy hydrocarbons fraction comprising hydrocarbon containing five or more carbon atoms that is suitable for use as a blend component of liquid transportation fuel, wherein the light hydrocarbons fraction is contacted with an oligomerization catalyst at a temperature and a pressure that facilitate the oligomerization of at least a portion of the light hydrocarbons fraction to produce larger hydrocarbons that are suitable for use as a blend component of liquid transportation fuel.

Assignees

• Phillips 66 Co

Inventors

• Weintrob Edward C
• Uppili Sundararajan
• Miller Clark A
• Choudhary Tushar V

Classifications

• C10G2400/30

  Aromatics · CPC title

• B01J21/005

  Spinels · CPC title

• B01J2523/82

  Metals of the platinum group · CPC title

• C10G59/06 Primary

  plural parallel stages only · CPC title

• C10G50/00

  Production of liquid hydrocarbon mixtures from lower carbon number hydrocarbons, e.g. by oligomerisation · CPC title