INTEGRATED PROCESS FOR ACTIVATING HYDROPROCESSING CATALYSTS WITH IN-SITU PRODUCED SULFIDES AND DISULPHIDES

Abstract

The invention involves an integrated process in which a hydrocarbon feedstock is treated with a caustic (alkaline) extraction to remove sulfides, disulfides, and mercaptans. These extracted materials are further treated, and are then used to activate hydrotreating catalysts.

Claims

1. An integrated process for removing sulfur containing hydrocarbons from a hydrocarbon feedstock and activating a hydroprocessing catalyst, comprising: (i) contacting said hydrocarbon feedstock to an alkaline extraction solution in an extraction vessel, to remove sulfides, disulfides, and mercaptans; (ii) reacting the mercaptans with an alkali in said alkaline extraction solution to form thiolates; (iii) contacting said thiolates with oxygen in the presence of a catalyst, to form a mixture of sulfides and disulfides; (iv) removing any sulfides and disulfides from said alkaline solution by adsorbing said sulfides and disulfides to an adsorbent to form a mixture; (v) removing any non-sulfur compounds from said mixture, and (vi) activating a hydroprocessing catalyst by contact of said sulfur containing compounds to said hydroprocessing catalyst.

2. The process of claim 1, comprising carrying out (i) and (ii) at a temperature of 15 C. to 80 C.

3. The process of claim 2, comprising carrying out (i) and (ii) at a temperature of 40 C. to 60 C.

4. The process of claim 1, comprising carrying out (i) and (ii) at a pressure of 10-50 bars.

5. The process of claim 1, comprising carrying out (iii) at a temperature of from 20 C. to 300 C.

6. The process of claim 5, comprising carrying out (iii) at a temperature of from 20 C. to 80 C.

7. (canceled)

7. (canceled)

8. (canceled)

9. The process of claim 1, comprising removing water soluble sulfur containing compounds in (iv) via a water wash.

10. (canceled)

11. The method of claim 10, wherein said adsorbent is activated carbon alumina, silica alumina, sand, a zeolite, or a regenerated spent catalyst.

12. The method of claim 1, wherein said hydrocarbon feedstream is natural gas, fuel gas, liquefied petroleum gas, a pentane mixture, light straight run naphtha, light thermally cracked naphtha, full straight run naphtha, full FCC cracked naphtha, heavy FCC cracked naphtha, heavy SR naphtha, aviation turbine fuel, kerosene, or a distillate fuel having a boiling point of up to 350 C.

13. The process of claim 1, wherein said extraction vessel comprises a plurality of liquid-liquid contacting decks.

14. (canceled)

15. (canceled)

Description

BRIEF DESCRIPTION OF THE FIGURES

[0020] FIG. 1 shows a conventional MEROX process.

[0021] FIG. 2 shows one embodiment of the invention, where DSO is produced and purified, then used to activate catalysts.

[0022] FIG. 3 shows a further embodiment of the invention in which extracted thiolates are converted to mercaptans, which are then used to activate catalysts.

[0023] FIG. 4 shows activation of a hydrotreating catalyst using a commercial disulfide and the extracted disulfide formed from the MEROX process as described in the invention.

[0024] FIG. 5 shows hydrotreating catalyst activity for a catalyst activated using commercial disulfide and the extracted disulfide formed from the MEROX process according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0025] Referring to FIG. 1, which shows a conventional MEROX process, one has two reaction vessels 1 and 2, for treatment of propane (1) and butane (2), obtained during refining. The propane and butane are not pure, and they are contacted to an alkaline or caustic solution introduced to the reaction vessel by 3. The contact takes place at a temperature that is preferably 40-60 C., but can range from 15-80 C., and a pressure which can range from 10-50 bars. Impure propane or butane 4 or 5 enters the reaction vessel 1 or 2, and after contact with the caustic solution, leaves, as shown by 6 and 7.

[0026] The caustic alkaline solution, which contains various thiolates of formula XSR, where X is an alkaline ion such as K.sup.+, or Na.sup.+, or some other component of an alkaline compound and R is as discussed supra, moves 8 to a second reaction vessel 9, which contains a catalyst 10, and to which oxygen containing air 11 is introduced. The contact preferably takes place at a temperature of from 20 C. to 300 C., more preferably at a temperature from 20 C. to 80 C., Following oxidation, a minor proportion of sulfides and a major proportion of disulfides 12 are produced, and are treated as discussed infra.

[0027] FIG. 2 shows one embodiment of the invention, where following the process elaborated supra, the solvent 12 containing the sulfides and disulfides is moved to a further reaction vessel 20, where solvent 21 is added and sulfides/disulphides are separated from the solvent into 22 (sulfides and disulfides) and 23 (solvent). The solvent is cleaned in solvent recovery vessel 24 and may be either reused 25, or disposed of 26, while purified sulfides/disulfides 22 move to a further reaction vessel 27, containing an inactive, hydroprocessing catalyst. Following contact, activated catalyst 28 is formed and is used in further processes. The cleaning of the solvent may be accomplished via various art recognized methodologies. Exemplary, but not inclusive, are a water wash, which removes water soluble sulfur containing compounds, and adsorption with, e.g., activated carbon, alumina, silica alumina, sand, a zeolite, or regenerated, spent catalyst.

[0028] FIG. 3 shows an embodiment of the invention very similar to that shows in FIG. 2, except that, in the vessel 30 comparable to 9 in FIG. 2, hydrolysis, using an acid rather than air, takes place, to form mercaptans of formula RSH, as defined supra, and sulfides. The mercaptan containing solution moves to purification reactor 40 via means 32 and is treated as described herein. This contact preferably takes place at a temperature of front 20 C. to 100 C., more preferably, at a temperature from 20 C. to 80 C. A further difference is that in this embodiment the product 33 leaving reactor 40 is a mixture of purified sulfides and mercaptans.

[0029] FIG. 4 is a further depiction of the activation of hydrotreating catalysts using DSO prepared in accordance with the invention, and used in the integrated process of the invention and is compared to the activation of the same catalyst using a commercially available disulfide.

[0030] FIG. 5 shows the hydrotreating catalyst activity experimental results when sulfiding the catalyst with the disulfide prepared in accordance with the invention and a commercially available disulfide.

[0031] As noted, supra, the MEROX reaction, as well as methods for separating the products produced in the oxidation of mercaptans, are known. What is not taught by the art, and which will be elaborated upon infra, is the use of these sulfide compounds as catalyst activation agents, especially in an integrated process whereby mercaptans in a hydrocarbon feedstock are oxidized, the sulfide oxidation products are used directly to activate catalysts which are used as part of the integrated process.

EXAMPLE 1

[0032] Two diesel hydrotreating pilot plant tests were conducted. The catalyst to be activated, in each test, was an NiMo hydrocracking catalyst in oxide form. The mode of activating the catalyst was to contact it with either commercially available DMDS, or recovered DSO, obtained via the integrated process of the invention,.

[0033] Activating solutions were prepared using kerosene fractions containing 1% sulfur, to which DSO was added, to obtain 2% sulfur content.

[0034] To activate the catalyst, the reaction vessel was pressurized to 45 bars, using hydrogen followed by a 30 minute purge. The hydrogen flow was 27.5 NL/h and the temperature was increased to 175 C., in 25 C./hr increments.

[0035] Commercially available activating solution (DMDS), was added at LHSV of 3 h.sup.1, and held for 3 hours. The temperature was increased to 250 C. at the same rate as above. The concentration of H.sub.2S in the vessel was monitored every 30 minutes, until the level in the off gas exceeded 0.2 V %. Catalyst activation continued for 8 hours.

[0036] The rate of activation of the catalysts can be seen in FIG. 4.

EXAMPLE 2

[0037] This example compares commercially available DMDS sulfiding to DSO obtained using the invention. The DSO was obtained by combining the DSOs from propane and butane MEROX units, as described supra.

[0038] Activating solutions were prepared using kerosene fractions containing 1% sulfur, to which DSO was added, to obtain 2% sulfur content.

[0039] The vessel was pressurized to 45 bars, with hydrogen gas, and purged for 30 minutes. The rate of hydrogen flow was set at 27.5 NL/h, and the reactor temperature was increased to 175 C., at a rate of 25 C./hour.

[0040] The catalyst activating solution was fed to the vessel, at a LHSV of 3 h.sup.1, and held for 3 hours. The reactor temperature was then increased to 250 C., at a rate of 25 C./hour. The H.sub.2S gas concentration was monitored every 30 minutes for sulfur breakthroughs, until the H.sub.2S concentration was greater than 0.2 V % in off gas. The vessel was held with the same gas and liquid flow rates for 8 hours, to complete activation.

[0041] FIG. 4 shows the activation data for both activating agents. It will be seen that the activation was similar.

EXAMPLE 3

[0042] The activated catalysts of Examples 1 and 2 were tested, using an SR gas oil, derived from a mix of Arabian light and heavy crude (25:75). Properties of the feedstock are in the following Table;

TABLE-US-00004 TABLE 4 Feedstock properties and composition. Property Unit Value Sulfur W % 1.45 Density g/cc 0.8448 Nitrogen ppmw 98 0 C. 113 5 C. 172 10 C. 198 20 C. 233 30 C. 254 40 C. 273 50 C. 293 60 C. 311 70 C. 330 80 C. 352 90 C. 379 95 C. 400 100 C. 437

[0043] The feedstock was tested at constant pressure of 46 bars, LHSV of 0.95 h.sup.1, and temperatures in the range 320 C.-400 C.

[0044] These conditions follow:

TABLE-US-00005 TABLE 5 Operating conditions of hydrotreating tests. Variable Unit Test 1 Test 2 Catalyst activating Agent DMDS DSO Hydrogen partial pressure Bar 46 46 LHSV h.sup.1 0.95 0.95 Temperature C. 300, 310, 320, 300, 320 and 340 330, 340, 350, 360, 380 and 400 Duration days 3 at each 3 at 300 and 2 days temperatures at 320 and 340

[0045] The results are presented in FIG. 5. As seen both commercial DMDS and extracted DSO were effective in activating the hydroprocessing catalysts, converting it from oxide form into sulfide form.

[0046] The foregoing invention describes an integrated process for removing sulfur containing hydrocarbons from hydrocarbon feed, and then processing these to materials useful for activating a hydrocracking catalyst. The sulfur compounds, once removed into a caustic solvent, may be treated in one of two ways, it being understood that mercaptans, when contacted with an alkali react as follows:

2RSH+2NaOH.fwdarw.2NaSR+2H.sub.2O

[0047] It is to be understood that NaOH is representative of other alkalis including, but not being, limited to KOH, LiOH, other alkali hydroxides, and other alkali materials.

[0048] The resulting thiolate, i.e., NaSR, or any compound of formula XSR (where X is the cation of the alkali), can then either be oxidized in the presence of a catalyst to form a disulfide, viz:

4XSR+O.sub.2+2H.sub.2O.fwdarw.2RSSR+4XOH

[0049] or can be treated in the presence of acid and a catalyst:

XSR+H.sub.3O.fwdarw.RSH+H.sub.2O+X

[0050] If the first reaction, i.e., oxidation, is used, it is preferably carried out at a temperature of 20 C. to 80 C., but can range from 20 C. to 300 C. The second reaction is preferably carried out at 20 C. to 100 C., and preferably at 20 C.-80 C., at a pressure of from 1-30 bars, and for 15-60 minutes, although these parameters are not critical.

[0051] Other features of the invention will be clear to the skilled artisan and need not he reiterated here.

[0052] The terms and expression which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expression of excluding any equivalents of the features shown and described or portions thereof, it being recognized that various modifications are possible within the scope of the invention.