Process to produce low sulfur catalytically cracked gasoline without saturation of olefinic compounds

• US 8,366,913 B2
• Filed: 02/15/2012
• Issued: 02/05/2013
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Original Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Inventors: Choi, Ki-Hyouk, Al-Shareef, Ali H., Al-Ghamdi, Sameer A.
• Primary Examiner(s): MCCAIG, BRIAN A
• Application Number:
  US13/397,429
• Publication Number:
  US 20120138510A1
• Time in Patent Office: 356 Days
• Field of Search: 208/208.R, 208/209, 208/212, 208/213, 208/216.R, 208/217, 208/250, 208/299, 208/302
• US Class Current: 208/213
• CPC Class Codes: C10G 2300/1044 Heavy gasoline or naphtha having a boiling range of about 100 - 180 °C
• CPC Class Codes: C10G 2300/107 Atmospheric residues having a boiling point of at least about 538 °C
• CPC Class Codes: C10G 2300/1074 Vacuum distillates
• CPC Class Codes: C10G 2300/1077 Vacuum residues
• CPC Class Codes: C10G 2300/202 Heteroatoms content, i.e. S, N, O, P
• CPC Class Codes: C10G 2300/207 Acid gases, e.g. H2S, COS, SO2, HCN
• CPC Class Codes: C10G 2300/301 Boiling range
• CPC Class Codes: C10G 2300/305 Octane number, e.g. motor octane number [MON], research octane number [RON]
• CPC Class Codes: C10G 2300/44 Solvents
• CPC Class Codes: C10G 2400/02 Gasoline
• CPC Class Codes: C10G 55/04 including at least one thermal cracking step
• CPC Class Codes: C10G 69/04 including at least one step of catalytic cracking in the absence of hydrogen

Abstract

The invention relates to a process for the desulfurization of a gasoline fraction with high recovery of olefins and reduced loss of Research Octane Number (RON). A petroleum fraction is contacted with hydrogen and a commercially available hydrodesulfurization catalyst under mild conditions with to remove a first portion of the sulfur present, and is then contacted with an adsorbent for the removal of additional sulfur.

Claims

1. A method for producing gasoline fraction having a reduced sulfur content comprising:

contacting an overcut heavy cat naphtha fraction with a hydrotreating catalyst in the presence of hydrogen gas to remove at least a portion of the sulfur present in the overcut heavy cat naphtha fraction and produce a low sulfur hydrotreated heavy cat naphtha effluent, said hydrotreating catalyst comprising a support selected from zeolite, synthetic clay, natural clay, activated carbon, activated carbon fiber and carbon black and at least one metal selected from chromium, molybdenum, tungsten, nickel and cobalt;

contacting the low sulfur hydrotreated heavy cat naphtha effluent with a solid adsorbent at a temperature of between about 0°

C. and 100°

C., wherein the solid adsorbent comprises a solid support and wherein the adsorbent is pretreated by pyrolyzing to a temperature of at least about 600°

C. in an inert atmosphere; and

recovering a product stream having reduced sulfur content.

2. The method of claim 1 wherein the product stream has a sulfur content of less than 20 ppm.

3. The method of claim 1 wherein contacting the overcut heavy cat naphtha with the hydrotreating catalyst removes up to 95% of the sulfur present and contacting the low sulfur hydrotreated heavy cat naphtha effluent with the adsorbent removes up to 95% of the remaining sulfur.

4. The method of claim 1 further comprising supplying the low sulfur hydrotreated heavy cat naphtha effluent to a liquid-gas separator to remove hydrogen and hydrogen sulfide from the effluent.

5. The method of claim 1 wherein the hydrotreating catalyst comprises:

one or more of the elements selected from boron, nitrogen, fluorine, chlorine, phosphorous, potassium, magnesium, sodium, rubidium, calcium, lithium, strontium and barium.

6. The method of claim 1 wherein the adsorbent comprises metal species appended to the surface thereof.

7. The method of claim 6 wherein at least a portion of the metal species are present as sulfides.

8. The method of claim 1 wherein the adsorbent comprises at least one Group IB metal and at least one Group IIB metal.

9. The method of claim 8 wherein the Group IB metal is selected from copper and the Group IIB metal is selected from zinc.

10. The method of claim 1 wherein the adsorbent is an activated carbon having a surface area greater than about 500 m²/g.

11. The method of claim 1 wherein the overcut heavy cat naphtha fraction is contacted with the hydrotreating catalyst at a temperature of between 300°

C. and 350°

C. and a pressures of between about 0.5 MPa and 5 MPa.

12. The method of claim 1 further comprising regenerating the adsorbent;

wherein regeneration of the adsorbent comprises washing the adsorbent with an organic solvent.

13. The method of claim 12 wherein the organic solvent is selected from toluene, benzene, xylene, straight run naphtha, ethanol, isopropanol, n-butanol, i-butanol, n-pentanol, i-pentanol, ketone, and mixtures thereof.

14. A process for producing a gasoline fraction having reduced sulfur content, comprising:

separating a high boiling fraction having a boiling range of about 60°

C. to 250°

C. from a full boiling point range catalytically cracking gasoline;

contacting the high boiling fraction with a hydrotreating catalyst in the presence of hydrogen to remove a portion of the sulfur compounds and produce a hydrodesulfurization product;

removing hydrogen sulfide and hydrogen gases from the hydrodesulfurization product to produce a stripper effluent;

contacting the stripper effluent with a solid adsorbent to remove sulfur compounds and produce a gasoline fraction having reduced sulfur content, wherein said solid adsorbent is pretreated by heating to a temperature of between about 400°

C. and 600°

C. in a nitrogen atmosphere and an oxygen content of between about 0.1 vol. % and 5 vol. %;

wherein the loss of Research Octane Number of the high boiling fraction is less than 2.

15. The process of claim 14, in which full boiling point range catalytically cracked gasoline is produced by fluidized catalytic cracking of light cycle oil, heavy cycle oil, vacuum gas oil, atmospheric resid, vacuum resid or their mixture.

16. The process of claim 14 wherein the hydrotreating catalyst comprises:

at least one support material selected from alumina, silica, silica-alumina, zeolite, synthetic clay, natural clay, activated carbon, activated carbon fiber, and carbon black;

a metal selected from Group VIB of the periodic table and at least one metal selected Group VIIIB of the periodic table; and

at least one element selected from boron, nitrogen, fluorine, chlorine, phosphorous, potassium, magnesium, sodium, rubidium, calcium, lithium, strontium, barium.

17. The process of claim 14 wherein the adsorbent comprises at least one metal selected from Group IB of the periodical table and at least one metal selected from Group IIB of the periodic table.

18. The process of claim 14 wherein the adsorbent is selected from silica, alumina, silica-alumina, zeolite, synthetic clay, natural clay, activated carbon, activated charcoal, activated carbon fiber, carbon fabric, carbon honeycomb, alumina-carbon composite, silica-carbon composite, and carbon black.

19. The process of claim 14 further comprising contacting the stripper effluent with a solid adsorbent in the absence of hydrogen.

20. A method for producing gasoline fraction having a reduced sulfur content comprising:

contacting an overcut heavy cat naphtha fraction with a hydrotreating catalyst in the presence of hydrogen gas to remove at least a portion of the sulfur present in the overcut heavy cat naphtha fraction and produce a low sulfur hydrotreated heavy cat naphtha effluent, said hydrotreating catalyst comprising a support selected from zeolite, synthetic clay, natural clay, activated carbon, activated carbon fiber and carbon black and at least one metal selected from chromium, molybdenum, tungsten, nickel and cobalt;

contacting the low sulfur hydrotreated heavy cat naphtha effluent with a solid adsorbent at a temperature of between about 0°

C. and 100°

C., wherein the solid adsorbent comprises a solid support and wherein the adsorbent is pretreated by heating to a temperature of between about 400°

C. and 600°

C. in a nitrogen atmosphere and an oxygen content of between about 0.1 vol. % and 5 vol. %; and

recovering a product stream having reduced sulfur content.

21. The method of claim 20 wherein the product stream has a sulfur content of less than 20 ppm.

22. The method of claim 20 wherein contacting the overcut heavy cat naphtha with the hydrotreating catalyst removes up to 95% of the sulfur present and contacting the low sulfur hydrotreated heavy cat naphtha effluent with the adsorbent removes up to 95% of the remaining sulfur.

23. The method of claim 20 further comprising supplying the low sulfur hydrotreated heavy cat naphtha effluent to a liquid-gas separator to remove hydrogen and hydrogen sulfide from the effluent.

24. The method of claim 20 wherein the hydrotreating catalyst comprises:

one or more of the elements selected from boron, nitrogen, fluorine, chlorine, phosphorous, potassium, magnesium, sodium, rubidium, calcium, lithium, strontium and barium.

25. The method of claim 20 wherein the adsorbent comprises metal species appended to the surface thereof.

26. The method of claim 25 wherein at least a portion of the metal species are present as sulfides.

27. The method of claim 20 wherein the adsorbent comprises at least one Group IB metal and at least one Group IIB metal.

28. The method of claim 27 wherein the Group IB metal is selected from copper and the Group IIB metal is selected from zinc.

29. The method of claim 20 wherein the adsorbent is an activated carbon having a surface area greater than about 500 m²/g.

30. The method of claim 20 wherein the overcut heavy cat naphtha fraction is contacted with the hydrotreating catalyst at a temperature of between 300°

C. and 350°

C. and a pressures of between about 0.5 MPa and 5 MPa.

31. The method of claim 20 further comprising regenerating the adsorbent;

wherein regeneration of the adsorbent comprises washing the adsorbent with an organic solvent.

32. The method of claim 31 wherein the organic solvent is selected from toluene, benzene, xylene, straight run naphtha, ethanol, isopropanol, n-butanol, i-butanol, n-pentanol, i-pentanol, ketone, and mixtures thereof.