Methods for recovering organic heteroatom compounds from hydrocarbon feedstocks

Patent metadata

Field	Value
Publication number	US-9394489-B2
Application number	US-201514617358-A
Country	US
Kind code	B2
Filing date	Feb 9, 2015
Priority date	Dec 16, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

Methods for recovering organic heteroatom compounds from a hydrocarbon feedstock include feeding into a contactor a hydrocarbon feedstock and an aqueous solvent to form an extraction mixture of the aqueous solvent with the hydrocarbon feedstock. The hydrocarbon feedstock includes a hydrocarbon and an organic heteroatom compound. The aqueous solvent includes an ionic liquid formed from pressurized carbon dioxide and water. A pressure and temperature of the extraction mixture may be established that together tune the aqueous solvent to selectively form a solvent complex with the at least one organic heteroatom compound. Then, the solvent complex is extracted to a recovery vessel from the extraction mixture in the contactor. By adjustment of a recovery temperature of the recovery vessel, a recovery pressure of the recovery vessel, or both, the solvent complex decomposes into carbon dioxide and the organic heteroatom compound. The organic heteroatom compound is then recovered from the recovery vessel.

First claim

What is claimed is:

1. A method for reducing or removing one or more organic heteroatom compounds from a hydrocarbon feedstock to form a lean hydrocarbon, the method comprising:
feeding a hydrocarbon feedstock into a contactor, the hydrocarbon feedstock comprising at least one hydrocarbon and at least one organic heteroatom compound, the at least one organic heteroatom compound chosen from nitrogen-containing heterocyclic compounds, sulfur-containing heterocyclic compounds, porphyrins, organometallic compounds, and combinations thereof;
feeding an aqueous solvent into the contactor to form an extraction mixture of the aqueous solvent with the hydrocarbon feedstock, the aqueous solvent comprising an ionic liquid formed from pressurized carbon dioxide and water;
establishing a contactor pressure and a contactor temperature of the extraction mixture in the contactor that together tune the aqueous solvent to selectively form a mixture containing a lean hydrocarbon and a solvent complex with the at least one organic heteroatom compound, wherein the contactor temperature is from greater than the critical temperature of carbon dioxide to about 100° C.;
extracting the solvent complex to a recovery vessel from the extraction mixture in the contactor; and
recovering the lean hydrocarbon from the contactor.

2. The method of claim 1 , further comprising recovering the at least one organic heteroatom compound from the solvent complex.

3. The method of claim 2 , wherein the organic heteroatom compound is recovered from the solvent complex by adjusting a recovery temperature of the recovery vessel, a recovery pressure of the recovery vessel, or both, to decompose the solvent complex in the recovery vessel into carbon dioxide and the at least one organic heteroatom compound, the method further comprising recovering the at least one organic heteroatom compound from the recovery vessel.

4. The method of claim 3 , wherein adjusting the recovery temperature of the recovery vessel, the recovery pressure of the recovery vessel, or both, comprises reducing the recovery pressure to less than the contactor pressure.

5. The method of claim 3 , wherein adjusting the recovery temperature of the recovery vessel, the recovery pressure of the recovery vessel, or both, comprises lowering the recovery temperature to less than the contactor temperature.

6. The method of claim 1 , wherein the hydrocarbon feedstock comprises crude oil or a crude oil fraction.

7. The method of claim 1 , wherein the at least one organic heteroatom compound is selected from the group consisting of pyrrole, pyridine, quinoline, carbazole, indole, nickel-tetraphenyl-porphyrin, vanadyl-tetraphenyl-porphyrin, thiophene, benzothiophene, dibenzothiophene, and 7,8,9,10-tetrahydro-benzo[b]naphtho[2,3-d]thiophene, and combinations thereof.

8. The method of claim 1 , wherein the contactor pressure is from about 2 bar to about 300 bar.

9. The method of claim 8 , wherein the contactor pressure is greater than or equal to the critical pressure of CO 2 .

10. The method of claim 1 , wherein recovering the at least one organic heteroatom compound comprises mixing an aromatic solvent with the solvent complex.

11. The method of claim 1 , wherein:
feeding the hydrocarbon feedstock comprises spraying the hydrocarbon feedstock into a bottom of the contactor; and
feeding the aqueous solvent comprises spraying the aqueous solvent into a top of the contactor.

12. The method of claim 11 , wherein the density of the aqueous solvent is greater than the density of the hydrocarbon feedstock, whereby the extraction mixture phase separates into at least an organic phase and an aqueous phase and at least a portion of the solvent complex migrates into the aqueous phase.

13. The method of claim 12 , wherein extracting the solvent complex comprises removing the at least a portion of the solvent complex from the aqueous phase or from a CO 2 phase that forms above the aqueous phase in the contactor.

14. The method of claim 1 , further comprising mixing the hydrocarbon feedstock with supercritical CO 2 before feeding the hydrocarbon feedstock into the contactor.

15. The method of claim 1 , further comprising reducing or removing at least one additional organic heteroatom compounds in at least one additional contactor in series with the contactor, wherein in each additional contactor a contactor pressure and a contactor pressure are established that together tune an aqueous solvent to selectively form a solvent complex with at least one organic heteroatom compound remaining in a lean hydrocarbon fed into the additional contactor.

16. The method of claim 1 , wherein the lean hydrocarbon comprises at least one second organic heteroatom compound not extracted from the hydrocarbon stream in the contactor, the method further comprising:
feeding the lean hydrocarbon into a second contactor;
feeding a second aqueous solvent into the second contactor to form a second extraction mixture of the second aqueous solvent with the lean hydrocarbon, the second aqueous solvent comprising an ionic liquid formed from pressurized carbon dioxide and water;
establishing a second contactor pressure and a second contactor temperature of the second extraction mixture in the second contactor that together tune the second aqueous solvent to selectively form a mixture containing a second lean hydrocarbon and a second solvent complex with the at least one second organic heteroatom compound;
extracting the second solvent complex to a second recovery vessel from the second extraction mixture in the second contactor; and
recovering the second lean hydrocarbon from the second contactor.

17. The method of claim 1 , wherein the at least one organic heteroatom compound comprises a nitrogen-containing heterocyclic compound.

18. The method of claim 17 , wherein:
the hydrocarbon feedstock is crude oil or a crude fraction; and
the nitrogen-containing heterocyclic compound is chosen from pyrrole, pyridine, quinoline, carbazole, indole, and combinations thereof.

19. The method of claim 1 , wherein the at least one organic heteroatom compound comprises a sulfur-containing heterocyclic compound.

20. The method of claim 19 , wherein:
the hydrocarbon feedstock is crude oil or a crude fraction; and
the sulfur-containing heterocyclic compound is chosen from thiophene, benzothiophene, dibenzothiophene, and 7,8,9,10-tetrahydro-benzo[b]naphtho[2,3-d]thiophene, and combinations thereof.

21. The method of claim 1 , wherein the at least one organic heteroatom compound comprises an organometallic compound.

22. The method of claim 21 , wherein the organometallic compound is a porphyrin.

23. The method of claim 22 , wherein:
the hydrocarbon feedstock is crude oil or a crude fraction; and
the porphyrin is chosen from nickel-tetraphenyl-porphyrin, vanadyl-tetraphenyl-porphyrin, and combinations thereof.

24. The method of claim 1 , wherein the contactor comprises electrical plates, the method further comprising activating the electrical plates to align ions of the ionic liquid and ions of the at least one organic heteroatom compound.

25. The method of claim 1 , wherein the contactor is a packed bed contactor, a fluidized bed contactor, or a baffled contactor.

26. The method of claim 1 , wherein:
the density of the aqueous solvent is greater than the density of the hydrocarbon feedstock; and
the hydrocarbon feedstock is fed by

Assignees

• Saudi Arabian Oil Co

Inventors

• Yusuf Zaki
• Hammad Ahmad D
• Souentie Stamatios
• Fadhel Bandar
• Rasheedi Nayif

Classifications

• C10G32/02

  by electric or magnetic means · CPC title

• C10G2300/205

  Metal content · CPC title

• B01D11/0403 Primary

  with a supercritical fluid · CPC title

• C10G21/28 Primary

  Recovery of used solvent · CPC title

• C10G2300/44

  Solvents · CPC title