Two-stage hydrocracking unit with intermediate HPNA hydrogenation step

Patent metadata

Field	Value
Publication number	US-11136512-B2
Application number	US-201916704871-A
Country	US
Kind code	B2
Filing date	Dec 5, 2019
Priority date	Dec 5, 2019
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

A method and a system for hydrocracking an oil feedstock to produce a light oil stream without build-up of heavy polynuclear aromatic (HPNA) hydrocarbons in the recycle stream. The method may include hydrocracking an oil feedstock, separating the produced effluent into a first, second, and third product stream, and hydrogenating the third product stream in a third reactor over a noble metal hydrogenation catalyst at an operational pressure equal to or less than the second reactor.

First claim

What is claimed is:

1. A method of hydrocracking an oil feedstock to produce a light oil stream without build-up of heavy polynuclear aromatic (HPNA) hydrocarbons in a recycle stream, the method comprising the steps of:
hydrocracking the oil feedstock with a first stage hydrocracking catalyst possessing hydrotreating and hydrocracking functionality in a first reactor to produce an effluent stream;
fractionating the effluent stream into first, second and third product streams, wherein the first product stream comprises C 1 -C 4 , naphtha, and diesel boiling in the range of 36-370° C., the second product stream comprises hydrocarbon components having an initial nominal boiling point of 370° C. and a final boiling point ranging from 420-750° C., and the third product stream comprises HPNA hydrocarbons and other hydrocarbons boiling above 420° C. to 750° C., depending upon the final boiling point of the second product stream;
cracking the second product stream in a second reactor; and
hydrogenating the third product stream in a third reactor over a noble metal hydrogenation catalyst at an operational pressure equal to or less than the second reactor.

2. The method of claim 1 , wherein the feedstock oil comprises at least one of a vacuum gas oil, deasphalted or demetalized oil from a solvent deasphalting process, light and heavy coker gas oils from a coker process, cycle oils from a fluid catalytic cracking (FCC) process derived from crude oils, synthetic crude oils, heavy oils and/or bitumen, shale oil and coal oils.

3. The method of claim 1 , wherein hydrocarbons after reactions in the second reactor and third reactor are sent to a separation unit.

4. The method of claim 1 , wherein the hydrogenation catalyst of the third reactor is selected from the group consisting of zeolite based catalysts, amorphous alumina catalysts, amorphous silica-alumina catalysts, titania catalysts, and a combination comprising at least one of zeolite based catalysts, amorphous alumina catalysts and amorphous silica alumina catalysts, wherein the average pore diameter is at least 100 angstroms.

5. The method of claim 4 , wherein the average pore diameter of the hydrogenation catalyst is at least 500 angstroms.

6. The method of claim 1 , wherein the noble metal hydrogenation catalyst comprises one or more metals selected from the group consisting of Pt, Pd, Ru, or a mixture thereof.

7. The method of claim 1 , wherein the third reactor comprises an unsupported metal catalyst.

8. The method of claim 7 , wherein the unsupported catalyst is composed of at least one or more selected from the group of Ni, Mo, W, Co, Zn, Zr, or a mixture thereof.

9. The method of claim 1 , wherein the first reactor further hydrodesulfurizes and hydrodenitrogenizes the oil feedstock, and the first product stream further includes H 2 S and NH 3 .

10. The method of claim 1 , wherein the first stage hydrocracking catalyst is selected from the group consisting of amorphous alumina catalysts, amorphous silica alumina catalysts, zeolite based catalyst, and a combination comprising at least one of amorphous alumina catalysts, amorphous silica alumina catalysts and zeolite based catalyst.

11. The method of claim 10 , wherein the first stage hydrocracking catalyst further comprises an active phase of Ni, W, Mo, Co, or a combination comprising at least one of Ni, W, Mo and Co.

12. The method of claim 10 , wherein 10% to 80% by volume of hydrocarbons boiling above 370° C. at a hydrogen partial pressure in the range of 100-200 kg/cm 2 are converted to one or more light gases selected from the group consisting of methane, ethane, propane, n-butane, isobutene, hydrogen sulfide, ammonia, naphtha fractions boiling in the range of 36° C. to 180° C., diesel fractions boiling in the range of 180° C. to 375° C., and combinations comprising at least one of the foregoing light gases.

13. The method of claim 12 , wherein the hydrogen partial pressure is 100-150 kg/cm 2 .

14. The method of claim 12 , wherein the flow of feedstock oil is in the range of 300-2000 m 3 over 1000 m 3 of hydrotreating catalyst per hour.

15. The method of claim 1 , wherein the operational pressure of the third reactor is 50-90 kg/cm 2 .

Assignees

• Saudi Arabian Oil Co

Inventors

• Koseoglu Omer Refa

Classifications

• C10G69/00

  Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process (C10G67/00 takes precedence) · CPC title

• C10G49/02 Primary

  characterised by the catalyst used · CPC title

• C10G2400/28

  Propane and butane · CPC title

• C10G2300/70

  Catalyst aspects · CPC title

• C10G45/52

  containing platinum group metals or compounds thereof · CPC title