INTEGRATED HYDROTREATING AND ISOMERIZATION PROCESS WITH AROMATIC SEPARATION

• US 20130062256A1
• Filed: 07/27/2012
• Published: 03/14/2013
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia)
• Original Assignee: Omer Refa Koseoglu
• Inventors: KOSEOGLU, Omer Refa
• Granted Patent: US 8,852,426 B2
• Time in Patent Office: Days
• US Class Current: 208/87
• CPC Class Codes: B01D 11/043 with stationary contacting elements, sieve plates or loose contacting elements
• CPC Class Codes: B01D 11/0457 comprising rotating mechanisms, e.g. mixers, mixing pumps
• CPC Class Codes: B01D 11/0461 mixing by counter-current streams provoked by centrifugal force
• CPC Class Codes: B01D 17/0202 by ab- or adsorption
• CPC Class Codes: B01D 17/0217 by centrifugal force
• CPC Class Codes: B01D 17/041 with moving devices
• CPC Class Codes: B01D 17/047 with separation aids
• CPC Class Codes: C10G 21/12 Organic compounds only
• CPC Class Codes: C10G 2300/1096 Aromatics or polyaromatics
• CPC Class Codes: C10G 2300/202 Heteroatoms content, i.e. S, N, O, P
• CPC Class Codes: C10G 2300/4081 Recycling aspects
• CPC Class Codes: C10G 2300/44 Solvents
• CPC Class Codes: C10G 25/00 Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
• CPC Class Codes: C10G 65/043 at least one step being a change in the structural skeleton
• CPC Class Codes: C10G 65/12 including cracking steps and other hydrotreatment steps
• CPC Class Codes: C10G 67/04 including solvent extraction as the refining step in the absence of hydrogen
• CPC Class Codes: C10G 67/0418 The hydrotreatment being a hydrorefining
• CPC Class Codes: C10G 67/0436 The hydrotreatment being an aromatic saturation
• CPC Class Codes: C10G 67/06 including a sorption process as the refining step in the absence of hydrogen
• CPC Class Codes: C10G 69/02 plural serial stages only

Abstract

Deep desulfurization of hydrocarbon feeds containing undesired organosulfur compounds to produce a hydrocarbon product having low levels of sulfur, i.e., 15 ppmw or less of sulfur, is achieved by hydrotreating the feed under mild conditions, and separating the hydrotreated effluent into an aromatic-rich fraction which contains a substantial amount of the aromatic refractory and sterically hindered sulfur-containing compounds, and an aromatic-lean fraction. The aromatic-rich fraction is contacted with isomerization catalyst, and the isomerized aromatic-rich fraction is recycled to the mild hydrotreating process.

Claims

1. A method of processing a hydrocarbon feed to reduce the concentration of undesired organosulfur compounds comprising:

subjecting the hydrocarbon feed to a mild hydrotreating process effective to

convert labile organosulfur compounds and

produce a hydrotreated effluent containing converted compounds and unconverted sterically hindered refractory aromatic organosulfur compounds;

separating the hydrotreated effluent into an aromatic-lean fraction that is recovered as a hydrotreated hydrocarbon product and an aromatic-rich fraction that contains sterically hindered refractory aromatic organosulfur compounds;

contacting the aromatic-rich fraction with an isomerization catalyst in the presence of hydrogen to remove steric hindrance of certain compounds and produce an isomerized effluent including isomerate and any remaining unreacted hydrogen; and

recycling at least a portion of the isomerized effluent to the hydrotreating zone.

2. The method of claim 1, further comprising, prior to contacting the aromatic-rich fraction with an isomerization catalyst, contacting the aromatic-rich fraction with an adsorbent material to reduce the nitrogen content to produce an adsorption effluent.

3. The method of claim 1, further comprising,

prior to separating the hydrotreated effluent into an aromatic-lean fraction and an aromatic-rich fraction, flashing the hydrotreated effluent to produce a light hydrotreated effluent and a heavy hydrotreated effluent;

separating the heavy hydrotreated effluent into an aromatic-lean fraction and an aromatic-rich fraction; and

recovering the light hydrotreated effluent.

4. The method of claim 3, further comprising recycling at least a portion of the heavy hydrotreated effluent back to the step of mild hydrotreating.

5. The method of claim 1, further comprising,

subsequent to contacting the aromatic-rich fraction with an isomerization catalyst, flashing the isomerized effluent to produce a light isomerized effluent and a heavy isomerized effluent;

separating the heavy isomerized effluent into an aromatic-lean fraction and an aromatic-rich fraction; and

recovering the light isomerized effluent.

6. The method of claim 5, further comprising recycling at least a portion of the heavy isomerized effluent back to the step of mild hydrotreating.

7. The method of claim 1, wherein separating the hydrotreated effluent into an aromatic-lean fraction and an aromatic-rich fraction comprises:

subjecting the hydrotreated effluent and an effective quantity of extraction solvent to an extraction zone to produce

an extract containing a major proportion of the aromatic content of the hydrotreated effluent and a portion of the extraction solvent and

a raffinate containing a major proportion of the non-aromatic content of the hydrotreated effluent and a portion of the extraction solvent;

separating at least substantial portion of the extraction solvent from the raffinate and retaining the aromatic-lean fraction;

separating at least substantial portion of the extraction solvent from the extract and retaining the aromatic-rich fraction.

8. The method of claim 1, wherein the aromatic-lean fraction includes aliphatic organosulfur compounds.

9. The method of claim 8, wherein the aliphatic organosulfur compounds include sulfides, disulfides, and mercaptans.

10. The method of claim 1, wherein the aromatic-rich fraction includes benzothiophene, alkylated derivatives of benzothiophene, dibenzothiophene, alkyl derivatives of dibenzothiophene, benzonaphtenothiophene, and alkyl derivatives of benzonaphtenothiophene.

11. The method of claim 1, wherein the aromatic-rich fraction includes aromatic nitrogen compounds including pyrrole, quinoline, acridine, carbazole and their derivatives.

12. The method of claim 2, wherein the step of contacting the aromatic-rich fraction with an adsorbent material comprises

a. passing the aromatic-rich fraction through a first of two packed columns;

b. transferring the aromatic-rich fraction from the first column to the second column while discontinuing passage through the first column;

c. desorbing and removing nitrogen-containing compounds and/or poly-nuclear aromatic compounds from the adsorbent material in the first column to thereby regenerate the adsorbent material;

d. transferring the aromatic-rich fraction from the second column to the first column while discontinuing the flow through the second column;

e. desorbing and removing nitrogen-containing compounds and/or poly-nuclear aromatic compounds from the adsorbent material in the second column to thereby regenerate the adsorbent material; and

f. repeating steps (a)-(e), whereby the processing of the aromatic-rich fraction is continuous.

13. An apparatus for processing a hydrocarbon feed containing undesired organosulfur compounds comprising:

a mild hydrotreating zone operable to convert labile organosulfur compounds, the mild hydrotreating zone including an inlet for receiving the hydrocarbon feed and an outlet for discharging hydrotreated effluent;

an aromatic separation zone operable to extract aromatic organosulfur compounds from the hydrotreated effluent, the aromatic separation zone including an inlet for receiving the hydrotreated effluent, an aromatic-rich outlet and an aromatic-lean outlet; and

an isomerization reaction zone having

an inlet in fluid communication with the aromatic-rich outlet and

an isomerization reaction zone outlet in fluid communication with the mild hydrotreating zone inlet for recycling isomerate.

14. The apparatus as in claim 13, further comprising a flashing zone having an inlet in fluid communication with the hydrotreated effluent discharge outlet, an outlet for discharging light hydrotreated effluent and an outlet in fluid communication with the aromatic separation zone for discharging heavy hydrotreated effluent.

15. The apparatus as in claim 13, further comprising a flashing zone having an inlet in fluid communication with the isomerized effluent discharge outlet, an outlet for discharging light isomerized effluent and an outlet in fluid communication with the aromatic separation zone for discharging heavy isomerized effluent.

16. The apparatus as in claim 13, further comprising an adsorption zone having an inlet in fluid communication with the aromatic-rich discharge outlet and an adsorption zone outlet for discharging extract having a reduced concentration of nitrogen-containing compounds, wherein the isomerization reaction zone inlet is in fluid communication with the adsorption zone outlet.