HYDROPROCESSING CATALYST HAVING AN ORGANIC ADDITIVE WITH METALS INCORPORATED USING CHELANT AND METHOD OF MAKING AND

USING SUCH CATALYST

This application claims the benefit of U.S. Provisional Patent Application 62/923,389 filed October 18, 2019 entitled HYDROPROCESSING CATALYST HAVING AN ORGANIC ADDITIVE WITH METALS INCORPORATED USING CHELANT AND METHOD OF MAKING AND USING SUCH CATALYST, the entirety of which is incorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to a hydroprocessing catalyst composition that includes an inorganic support having been impregnated with a solution of a hydrogenation metal component and a metal complexing agent and finished with an organic additive blend of an acetate compound and an unsaturated fatty amine compound, a method of making the catalyst composition, and the use of the catalyst composition.

BACKGROUND OF THE INVENTION

Hydroprocessing catalysts are used in processes to remove organic sulfur and nitrogen compounds from hydrocarbon feedstocks that are typically derived from the distillation of crude petroleum. In these processes the organic sulfur and nitrogen compounds are catalytically converted in the presence of hydrogen respectively to hydrogen sulfide and ammonia to then subsequently be removed from the hydrotreated feedstock.

Typical hydroprocessing catalysts include a carrier having deposited thereon a Group VIB metal, such as molybdenum and tungsten, and a Group VIII metal, such as nickel and cobalt. Phosphorus may also be present in the hydroprocessing catalyst. One method of preparing a hydroprocessing catalyst includes impregnating a carrier with the hydrogenation metal components followed by calcining the impregnated carrier to convert the metal components into oxides. The calcined catalyst is then subjected to a sulfidation treatment to convert the metal oxides to metal sulfide.

Presented in the prior art are many different catalyst compositions that are useful in hydroprocessing of hydrocarbon feedstocks. For instance, US 9,156,029 (Gabrielov et al.) discloses a hydroprocessing catalyst having a support loaded with an active metal precursor, an amine component, and a non-amine containing polar additive. The catalyst is made by incorporating a metal component into the support material to give a metal-loaded support followed by impregnation with the amine compound and non-amine containing polar additive. This impregnated composition is then treated with hydrogen and a sulfur compound and used in the hydrotreating of a hydrocarbon feedstock.

Another catalyst found to be useful in hydroprocessing of hydrocarbon feedstocks is disclosed in US 8,262,905 (Gabrielov et ah). This catalyst is prepared by incorporating a metal component into a support material to provide the support material loaded with the metal followed by impregnation with a hydrocarbon oil and a polar additive. The impregnated composition is then treated with hydrogen and a sulfur compound and used in the hydrotreating of a hydrocarbon feedstock.

US 9,211,536 (Gabrielov et al.) discloses a hydroprocessing catalyst having exceptional hydrodesulfurization and hydrodenitrogenation activity and good catalytic stability. This catalyst includes a shaped support formed from a mixture of inorganic oxide powder and catalyst fines. Incorporated into the shaped support that has been dried and calcined are a chelating agent, at least one catalytic metal, and a polar additive. The polar additive is impregnated into the dried chelant treated metal-incorporated support. This composition is then treated with hydrogen and a sulfur compound and used in the hydrotreating of a hydrocarbon feedstock.

US 9,376,637 (Gabrielov et al.) discloses another exceptional hydroprocessing catalyst. This catalyst comprises a shaped support that has had a metal solution with a chelating agent incorporated into the shaped support by a single-step impregnation. Incorporated into this dried metal-incorporated support is a polar additive followed by treatment with hydrogen and sulfur to provide the catalyst composition. This activated additive impregnated composition may suitably be used in hydrotreating of distillate feedstocks.

There is an ongoing need to find new and improved hydroprocessing catalysts with enhanced catalytic properties. Industry is perpetually searching for better hydroprocessing catalyst compositions that are highly active and stable when used in the treatment of petroleum- derived hydrocarbon process streams that have high concentrations of sulfur and nitrogen.

BRIEF SUMMARY OF THE INVENTION

It, thus, is an object of this invention to provide a composition that is useful and highly active in the catalytic hydrotreating of hydrocarbon feedstocks and a method of preparing such a composition.

Accordingly, provided is a hydroprocessing catalyst, comprising an inorganic oxide support particle impregnated with a metal impregnation solution, including a metal complexing agent and either cobalt or nickel, or both, and molybdenum, and further having incorporated therein an organic additive blend, comprising an acetate compound and unsaturated fatty amine compound.

The hydroprocessing catalyst is made by impregnating an inorganic oxide support particle with a metal impregnation solution, comprising at least one hydrogenation metal component and a metal complexing agent, to provide a metal-impregnated particle. The metal- impregnated particle is dried to provide a dried particle that is impregnated with an organic additive blend, comprising an acetate compound and an unsaturated fatty amine compound.

The inventive hydroprocessing catalyst and the catalyst composition made by the inventive method can be used to treat hydrocarbon feedstocks by contacting a feedstock with the catalyst under hydroprocessing conditions to yield a treated hydrocarbon effluent.

DETAILED DESCRIPTION OF THE INVENTION

The composition of the invention is particularly useful in applications involving the catalytic hydroprocessing of petroleum derived feedstocks, such as in the hydrotreating of atmospheric distillates, gas oils and residues and of vacuum gas oils and residues.

The inventive catalyst composition comprises an inorganic oxide support particle that has been impregnated with a metal impregnation solution that includes a metal complexing agent and either cobalt or nickel, or both, and molybdenum over which is incorporated an organic additive blend, comprising an acetate compound and an unsaturated fatty amine. This inventive composition exhibits improved hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activity over comparative catalyst compositions. This improvement in catalytic performance is attributed to the combined application of the metal complexing agent as a component of the metal impregnation solution used to yield a metal-impregnated particle with the subsequent impregnation of the metal-impregnated particle with a specific organic additive blend or mixture. In other words, the combined use of the metal complexing agent of the invention with the metal impregnation of the inorganic oxide support particle and the incorporation of the organic additive blend provides the inventive hydroprocessing catalyst having enhanced catalytic properties.

It is theorized that the application of the metal complexing agent contributes to the enhanced properties of the inventive additive-impregnated catalyst in a synergistic way with the incorporation of organic additive. It does this by forming metal chelate complexes with the metals that are incorporated into the inorganic support of the catalyst. The formation of the metal chelate complexes helps in the dispersion of the metals when the organic additive is subsequently incorporated into the inorganic support. This is because the chelation reaction pulls the metals out from or prevents the metals from being strongly bound to the surface of the inorganic support which provides for improved dispersion of the metals when the metal-impregnated particle is further impregnated with the organic additive blend of the invention.

Any suitable method can be used to prepare the support particle of the inventive composition. In one method, the inorganic oxide is mixed with water to form a mixture. The mixture should have properties that allow it to be formed into particles such as aggregates, balls, extrudates, and pills. It is preferred for the mixture to be an extrudable mixture or paste so that it can be extruded and formed into extrudates. If required, one or more additives such as a peptizing agent and an extrusion aid can be mixed with the inorganic oxide and water. The peptizing agent may be any material that provides for peptization of the inorganic oxide. Examples of possible peptizing agents are selected from mineral acids such as nitric acid, hydrochloric acid and sulfuric acid. The formed support particle is dried and calcined to provide the support particle that is used in preparing the catalyst of the invention.

The inorganic porous refractory oxide used in the preparation of the support particle may be any material that suitably allows for incorporation of the metal hydrogenation components and for receiving the organic additive blend of the hydroprocessing catalyst. The inorganic porous refractory oxide of the support particle should have porosity that allows for further filling with a metal impregnation solution and, after drying, filling with the organic additive blend of the invention.

Examples of possible suitable inorganic porous refractory oxides of the support particle include silica, alumina, titania, zirconia, silica-alumina, silica-titania, silica-zirconia, titania- alumina, zirconia-alumina, silica-titania and combinations of two or more thereof. The preferred porous refractory oxide for use in the preparation of the support of the inventive composition is one selected from the group consisting of alumina, silica, and silica-alumina. Among these, the most preferred porous refractory oxide is alumina.

The porous refractory oxide generally may have an average pore diameter in the range of from about 50 Angstroms to about 200 Angstroms. The total pore volume of the porous refractory oxide as measured by standard mercury porosimetry methods is in the range of from about 0.2 cc/gram to about 2 cc/gram.

The surface area of the porous refractory oxide, as measured by the B.E.T. method, generally exceeds about 100 m ² /gram, and it is typically in the range of from about 100 m ² /gram to about 500 m ² /gram, or in the range of from 125 to 400 m ² /gram.

In the preparation of the support particle it is dried under standard drying conditions that can include a drying temperature in the range of from 50 °C to 200 °C, preferably, from 75 °C to 175 °C, and more preferably, from 90 °C to 150 °C. After drying, the support particle is calcined under standard calcination conditions that include a calcination temperature in the range of from 250 °C to 900 °C, preferably, from 300 °C to 800 °C, and, most preferably, from 350 °C to 600 °C.

The support particle should have a surface area and pore volume that allow for its impregnation with an impregnation solution, comprising a hydrogenation metal component and a metal complexing agent, followed by impregnation with the organic additive blend of the invention. The support particle can have a surface area (determined by the BET method employing N2, ASTM test method D3037) that is in the range of from 50 m ² /g to 450 m ² /g, preferably, from 75 m ² /g to 400 m ² /g, and, most preferably, from 100 m ² /g to 350 m ² /g.

The mean pore diameter in angstroms (A) of the support particle is in the range of from 50 to 200, preferably, from 70 to 150, and, most preferably, from 75 to 125. The pore volume of the support particle should exceed 0.55 cc/g and is typically in the range of from 0.5 cc/g to 1.1 cc/g. More typically, the pore volume is in the range of from 0.6 cc/g to 1.0 cc/g, and, most typically, it is from 0.7 to 0.9 cc/g.

The references herein to pore size distribution and pore volume of the support particle are properties as determined by mercury intrusion porosimetry, ASTM test method D 4284. The measurement of the pore size distribution of the support particle is by any suitable measurement instrument using a contact angle of 140° with a mercury surface tension of 474 dyne/cm at 25 °C.

To provide the metal-impregnated particle of the invention, the support particle is impregnated with a metal impregnation solution. The impregnation solution comprises at least one hydrogenation metal component and a metal complexing agent. The support particle is impregnated with amounts of the hydrogenation metal component or components to provide a metals content in the final catalyst within the required concentration ranges for having an effective catalyst. The concentration of the metal complexing agent in the metal impregnation solution should provide for a final catalyst having enhanced catalytic properties after the impregnation of the organic additive blend of the invention.

The support particle is impregnated in one or more impregnation steps with at least one metal component using one or more aqueous solutions containing at least one metal salt wherein the metal compound of the metal salt solution is an active metal or active metal precursor. The metal elements are those selected from Group 6 of the IUPAC Periodic Table of the elements (e.g., chromium (Cr), molybdenum (Mo), and tungsten (W)) and Groups 9 and 10 of the IUPAC Periodic Table of the Elements (e.g., cobalt (Co) and nickel (Ni)). Phosphorous (P) is also a desired metal component.

For the Group 9 and 10 metals, the metal salts used to prepare the impregnation solution include Group 9 or 10 metal acetates, formats, citrates, oxides, hydroxides, carbonates, nitrates, sulfates, and two or more thereof. The preferred metal salts are metal nitrates, for example, such as nitrates of nickel or cobalt, or both. For the Group 6 metals, the metal salts include Group 6 metal oxides or sulfides. Preferred are salts containing the Group 6 metal and ammonium ion, such as ammonium heptamolybdate and ammonium dimolybdate.

The concentration of the metal compounds in the metal impregnation solution is selected to provide the desired metal content in the final composition of the invention taking into consideration the pore volume of the support particle into which the aqueous solution is impregnated. The metal concentrations in the final composition of the invention are as described herein. Typically, the concentration of metal compound in the impregnation solution is in the range of from 0.01 to 100 moles of metal per liter of solution.

The concentration of the metal complexing agent in the metal impregnation solution is selected to provide for reaction with a sufficient portion of its metal components to yield, after impregnation of the support particle with the organic additive blend, a final catalyst composition having enhanced catalytic properties. The amount of the metal complexing agent, also referred to as a chelating agent, in the metal impregnation solution should be in the range of from 0.5 weight percent (wt.%) to 15 wt.% of the total weight of the metal impregnation solution. It is more specifically in the range of from 1 wt.% to 13 wt. %, and, most specifically, from 2 wt.% to 12 wt.% of the total weight of the metal impregnation solution.

It has been found that there is a synergistic effect from using as described herein the chelating agent of the invention in combination with impregnation of the dried metal- impregnated particle or dried particle with the organic additive blend of the invention. The chelating agent of the invention is desirably a sugar alcohol or a compound containing at least two carboxylic moieties or a combination of these compounds.

It is preferred for the sugar alcohol to be selected from a group consisting of sugar alcohols having from 4 to 7 carbon atoms per molecule. Examples of these sugar alcohols include erythritol (C4), threitol (C4), arabitol (C5), xylitol (C5), ribitol (C5), mannitol (C6), sorbitol (C6), galactitol (C6), fucitol (C6), iditol (C6), inositol (C6), and volemitol (C7). The more preferred sugar alcohols are those having either five or six carbons per molecule. Among these more preferred sugar alcohols is xylitol and sorbitol.

Compounds containing two or more carboxyl functional groups that are suitable chelating agents of the invention include dicarboxylic acid compounds and tricarboxylic acid compounds. The dicarboxylic acid compounds can be selected from among compounds having 4 to 6 carbon atoms per molecule. The tricarboxylic acid compounds can be selected from among compounds having from 5 to 7 carbon atoms. A preferred dicarboxylic acid compound is malic acid (C4H6O5). A preferred tricarboxylic acid compound is citric acid (C6H8O7).

The amount of chelating agent relative to the amount of metal components contained in the metal impregnation solution is important because the formation of metal coordination complexes is required to provide a final catalyst composition having improved properties. The concentration of the chelating agent relative to the total metal concentration in the metal impregnation solution should be within the range of from 0.01 : 1 to 20: 1, based on the ratio of the total weight of the chelating agent per total weight of metal as elements, e.g. the total weight of nickel and molybdenum, or total weight of cobalt and molybdenum, or total weight of cobalt, nickel, and molybdenum.

It is desired for the weight ratio of chelating agent-to-total metal components in the metal impregnation solution to be at least 0.025: 1, and it is more desired for the weight ratio of chelating agent-to-total metal components in the metal impregnation solution to be at least 0.05:1, or at least 0.1:1. A desired upper limit for the weight ratio of chelating agent-to-total metal components in the metal impregnation solution is less than 15:1, and more desired the upper limit is less than 10: 1.

The amount of metal in the metal-impregnated support particle can depend upon the application for which the final composition of the invention is to be used. Generally, for hydroprocessing applications, the Group 9 and 10 metal components, i.e., cobalt or nickel, can be present in the support particle to provide a metal-impregnated support particle having a metal component incorporated therein in an amount in the range of from 0.5 wt. % to 20 wt. %, preferably from 1 wt. % to 15 wt. %, and, most preferably, from 2 wt. % to 12 wt. %. These weight percent values are based on the weight of the dry metal-impregnated support particle and the metal component in the elemental form regardless of its actual form, e.g., the oxide form or sulfide form, in the composition.

The Group 6 metal component, i.e., molybdenum or tungsten, preferably, molybdenum, is incorporated into the support particle in an amount in the range of from 5 wt. % to 50 wt. %, preferably from 8 wt. % to 40 wt. %, and, most preferably, from 12 wt. % to 30 wt. %. These weight percent values are based on the weight of the the dry metal-impregnated support particle and the metal components in the elemental form regardless of its actual form, e.g., the oxide form or sulfide form, in the composition.

In the inventive method of preparing or making the catalyst composition of the invention, the metal impregnation solution may be an aqueous solution comprising at least one hydrogenation metal component, as described above, having a hydrogenation function and the metal complexing agent. The at least one hydrogenation metal component of the metal impregnation solution may include, for example, a metal selected from the group consisting of nickel, cobalt, molybdenum, tungsten and any combination of two or more thereof, and is incorporated into the support particle to thereby provide a metal-impregnated support particle.

The incorporation of the metal impregnation solution into the support particle may be done by any suitable means or method known to those skilled in the art. Such method may include standard impregnation by incipient wetness or even soaking the support particle with an excess amount of the metal impregnation solution than would be used in a dry impregnation or an incipient wetness impregnation.

Regardless, however, of the actual means or method used to incorporate the metal impregnation solution into the support particle, the pores of the resulting metal-impregnated support particle are filled with the metal impregnation solution. As a result, the pores are not able to retain or be filled with additional volume of liquid or other material, such as the organic additive blend of the invention.

The metal-incorporated support particle, thus, undergoes a drying step by which at least a portion of the volatiles content is driven from the metal-impregnated support particle but leaving the metals behind upon the surface of the support particle. This provides a dried particle having available pore volume that can be filled with the organic additive blend of the invention. The dried particle is, thus, a support particle that has been impregnated with a metal impregnation solution that provides a metal-impregnated support particle. The metal-impregnated support particle is then dried giving the dried particle.

The metal-impregnated support particle is then dried under drying conditions that include a drying temperature that is less than a calcination temperature. This indeed is an important feature of the inventive method, which is to dry the metal-impregnated support particle at a drying temperature not exceeding a calcination temperature.

The drying temperature then should not exceed 400 °C, and, preferably, the drying temperature at which the metal-impregnated support particle is dried does not exceed 300 °C, and, most preferably, the drying temperature does not exceed 250 °C. It is understood that this drying step will, in general, be conducted at lower temperatures than those mentioned above. Typically, the drying temperature will be conducted at a temperature in the range of from 60 °C to 150 °C. This drying step provides a dried particle that may then be filled with the organic additive blend of the invention. The drying of the metal-impregnated support particle is preferably controlled in a manner to provide the resulting dried particle that has a volatiles content within a desired range. The volatiles content of the dried particle should be controlled so that it does not exceed 20 wt. % LOI. It is preferred for the LOI of the dried particle to be in the range of from 1 wt. % to 20 wt.

% LOI, and, most preferred, from 3 wt.% to 15 wt. % LOI.

LOI, or loss on ignition, is defined as the percentage weight loss of the material after its exposure to air at a temperature of 482 °C for a period of two hours. LOI can be represented by the following formula: (sample weight before exposure less sample weight after exposure) multiplied by 100 and divided by (sample weight before exposure).

The organic additive blend component of the inventive hydroprocessing catalyst is impregnated into available pore volume of the pores of the dried particle provided by drying of the metal-impregnated support particle. This is done by incorporating the organic additive blend into the dried particle to provide an additive impregnated dried particle by applying any suitable method or means to impregnate the dried particle with the organic additive blend.

The preferred method of impregnating the dried particle with the organic additive blend may be any standard well-known pore fill methodology whereby the pore volume is filled by taking advantage of capillary action to draw the liquid into the pores of the dried particle. The percentage of the pore volume of the dried particle that is filled with the organic additive blend is in the range of from 25% up to 100% of the available pore volume of the dried particle. Preferably, at least 50% of the available pore volume of the dried particle is filled with the organic blend, and, more preferably, at least 70% is filled with the organic additive blend. It is preferred for up to 100% of the available pore volume of the dried particle to be filled with the organic additive blend, but the pores of the additive impregnated dried particle may have up to 95% or even up to 90% of the available pore volume filled with the organic additive blend. The filling of the dried particle with the organic additive blend provides a final composition that when activated exhibits exceptional hydroprocessing catalytic properties.

The combined features of using a support particle, impregnated with both a hydrogenation metal and the metal complexing agent, that is further impregnated with an organic additive blend provide for the inventive composition having enhanced hydroprocessing activity. The organic additive blend component of the inventive catalyst comprises both an acetate compound and an unsaturated fatty amine. The organic additive blend should include its individual components at a weight ratio of the unstaturated fatty amine compound-to-acetate compound in the range of from 0.1:1 to 10:1. It is preferred for the organic additive blend to have a weight ratio of the unsaturated fatty amine-to-acetate in the range of from 0.2: 1 to 8: 1, and, more preferably, from 0.3: 1 to 2: 1. Most preferably, the weight ratio of the unsaturated fatty amine-to-acetate is in the range of from 30/70 to 15/10.

The acetate compound component of the organic additive blend used in the preparation of the inventive catalyst composition may be any suitable molecular compound having an acetate moiety and that contributes to the enhanced catalytic properties of the final catalyst composition of the invention. Such an acetate compound must be liquid under the temperature conditions of the catalyst preparation (typically within the temperature range of from 0 °C to 40 °C) and miscible with the unsaturated fatty amine component of the organic additive blend of the inventive catalyst composition.

The acetate compound of the organic additive blend may be selected from among suitable acetate compounds in the group consisting of alkyl acetates, ethoxy alkyl acetates, methoxy alkyl acetates, and alkoxy alkoxy alkyl acetates.

The alkyl acetates from which the acetate compound is selected may be represented by the formula: CH ₃ C(0)OR _n , wherein R represents an alkyl group and n = an integer of from 1 to 20 representative of the number of carbon atoms in R.

The ethoxy alkyl acetates from which the acetate compound is selected may be represented by the formula: CH ₃ CH ₂ 0R _n 0(0)CCH ₃ , wherein R represents the number of carbons within the range of n = an integer of from 1 to 10.

The methoxy alkyl acetates from which the acetate compound is selected may be represented by the formula: CH ₃ 0R _n 0(0)CCH ₃ , wherein R represents the number of carbons within the range of n = an integer of from 1 to 10.

The alkoxy alkoxy alkyl acetates from which the acetate compound is selected may be represented by the formula R _I 0R ₂ 0R ₃ 0(0)CCH ₃ , wherein Ri represents the number of carbons in the range of from 1 to 4, R2 represents the number of carbons in the range of from 1 to 4, R3 represents the number of carbons in the range of from 1 to 4, R4 represents the number of carbons in the range of from 1 to 4.

The most preferred acetate compound for use as a component of the organic additive blend is butyl carbitol acetate (butoxy ethoxy ethyl acetate). The unsaturated fatty amine compound component used in the preparation of the organic additive blend of the invention may be any suitable molecular compound that contributes to the enhanced properties of the final catalyst composition of the invention. Suitable unsaturated fatty amines are those that are miscible with the acetate compound used in the preparation of the organic additive blend.

The unsaturated fatty amine compound may be selected from among suitable unsaturated fatty amine compounds in the group of unsaturated fatty amines having 8 to 22 carbon atoms per molecule. The unsaturated fatty amine of the organic additive blend includes an amine moiety attached to a hydrocarbon chain of eight or more carbon atoms in length up to 22 carbon atoms with at least one carbon-carbon double bound within the hydrocarbon chain.

The most preferred unsaturated amine compound for use as a component of the organic additive blend is oleylamine (C18H35NH2 with a double bound on the ninth (9 ^th ) carbon).

The impregnation of the dried particle with the organic additive blend provides a composition that comprises the support particle, at least one hydrogenation metal, and the organic additive blend. As mentioned above, the amount of organic additive blend impregnated into the dried particle provides a pore volume fill of the dried particle with the organic additive blend in the range of from 25% up to 100% of the available pore volume. The pore volume of the dried particle can be measured by any suitable method or means know to those skilled in the art. One suitable method is to measure the water pore volume of the dried particles by water titration or by filling the dried particles with water and measuring the weight difference between the dried particles and the water-filled particles to determine the volume of adsorbed water.

The final or organic additive blend impregnated composition may be treated, either ex situ or in situ, with hydrogen and with a sulfur compound, and, indeed, it is one of the beneficial features of the invention that it permits the shipping and delivery of a non-sulfurized composition to a reactor in which it can be activated, in situ, by a hydrogen treatment step followed by a sulfurization step. The composition can first undergo a hydrogen treatment that is then followed with treatment with a sulfur compound.

The hydrogen treatment includes exposing the composition to a gaseous atmosphere containing hydrogen at a temperature ranging upwardly to 250 °C. Preferably, the impregnated composition is exposed to the hydrogen gas at a hydrogen treatment temperature in the range of from 100 °C to 225 °C, and, most preferably, the hydrogen treatment temperature is in the range of from 125 °C to 200 °C.

The partial pressure of the hydrogen of the gaseous atmosphere used in the hydrogen treatment step generally can be in the range of from 1 bar to 70 bar, preferably, from 1.5 bar to 55 bar, and, most preferably, from 2 bar to 35 bar. The impregnated composition is contacted with the gaseous atmosphere at the temperature and pressure conditions mentioned above for a hydrogen treatment time period in the range of from 0.1 hours to 100 hours, and, preferably, the hydrogen treatment time period is from 1 hour to 50 hours, and most preferably, from 2 hours to 30 hours.

Sulfiding of the composition after it has been treated with hydrogen can be done using any conventional method known to those skilled in the art. Thus, the hydrogen treated composition can be contacted with a sulfur-containing compound, which can be hydrogen sulfide or a compound that is decomposable into hydrogen sulfide, under the contacting conditions of the invention. Examples of such decomposable compounds include mercaptans, CS2, thiophenes, dimethyl sulfide (DMS), and dimethyl disulfide (DMDS). Also, preferably, the sulfiding is accomplished by contacting the hydrogen treated composition, under suitable sulfurization treatment conditions, with a hydrocarbon feedstock that contains a concentration of a sulfur compound. The sulfur compound of the hydrocarbon feedstock can be an organic sulfur compound, particularly, one which is typically contained in petroleum distillates that are processed by hydrodesulfurization methods.

Suitable sulfurization treatment conditions are those which provide for the conversion of the active metal components of the hydrogen treated composition to their sulfided form. Typically, the sulfiding temperature at which the hydrogen treated composition is contacted with the sulfur compound is in the range of from 150 °C to 450 °C, preferably, from 175 °C to 425 °C, and, most preferably, from 200 °C to 400 °C.

When using a hydrocarbon feedstock to sulfide the hydrogen treated composition, the sulfurization conditions can be the same as the process conditions under which the hydrotreating is performed. The sulfiding pressure at which the hydrogen treated composition is sulfided generally can be in the range of from 1 bar to 70 bar, preferably, from 1.5 bar to 55 bar, and, most preferably, from 2 bar to 35 bar. It is recognized that the final or additive -impregnated composition of the invention, after its treatment with hydrogen and sulfur, is a highly effective catalyst for use in the hydrotreating of hydrocarbon feedstocks. This catalyst is particularly useful in applications involving the hydrodesulfurization (HDS) or hydrodeni trogenation (HDN), or both, of hydrocarbon feedstocks, and, especially, it has been found to be an excellent catalyst for use in the HDS and HDN of gas oil feedstocks.

The inventive composition may be used as well to make ultra-low sulfur distillate product having a sulfur concentration of less than 15 ppmw, preferably, less than 10 ppmw, and, most preferably, less than 8 ppmw. Also, as noted, the inventive composition may be used to treat heavier hydrocarbon feedstocks, such as the gas oils. In the hydrotreatment of gas oil, the nitrogen content of the treated product is typically less than 1000 ppmw, or less than 800 ppmw, and, even less than 600 ppmw. The sulfur content of the treated product is typically less than 500 ppmw, or less than 400 ppmw, and, even less than 300 ppmw.

In hydrotreating applications, the composition, preferably is used in a delayed feed introduction procedure or otherwise treated with hydrogen and sulfur, as described above. In this procedure, the composition is contacted under suitable hydrodesulfurization conditions with a hydrocarbon feedstock that typically has a concentration of sulfur. This provides for sulfiding of the composition.

One hydrocarbon feedstock that may be processed using the inventive composition is a petroleum middle distillate cut having a boiling temperature at atmospheric pressure in the range of from 140 °C to 410 °C. These temperatures are approximate initial and boiling temperatures of the middle distillate. Examples of refinery streams intended to be included within the meaning of middle distillate include straight run distillate fuels boiling in the referenced boiling range, such as, kerosene, jet fuel, light diesel oil, heating oil, heavy diesel oil, and the cracked distillates, such as FCC cycle oil, coker gas oil, and hydrocracker distillates. The preferred distillate feedstock is a middle distillate boiling in the diesel boiling range of from about 140 °C to 400 °C.

The gas oils may also be processed using the inventive composition. These gas oils may include atmospheric gas oil, light vacuum gas oil, and heavy vacuum gas oil. It is further contemplated that the inventive composition may have use in the treatment of residuum feedstocks, as well. The sulfur concentration of the middle distillate feedstock can be a high concentration, for instance, being in the range upwardly to about 2 weight percent of the distillate feedstock based on the weight of elemental sulfur and the total weight of the distillate feedstock inclusive of the sulfur compounds. However, the distillate feedstock typically has a sulfur concentration in the range of from 0.01 wt.% (100 ppmw) to 1.8 wt.% (18,000). But, more typically, the sulfur concentration is in the range of from 0.1 wt.% (1000 ppmw) to 1.6 wt.% (16,000 ppmw), and, most typically, from 0.18 wt.% (1800 ppmw) to 1.1 wt.% (11,000 ppmw). It is understood that the references herein to the sulfur content of the distillate feedstock are to those compounds that are normally found in a distillate feedstock or in the hydrodesulfurized distillate product and are chemical compounds that contain a sulfur atom and which generally include organosulfur compounds.

The composition of the invention may be employed as a part of any suitable reactor system that provides for contacting it or its derivatives with the distillate feedstock under suitable hydrodesulfurization conditions that may include the presence of hydrogen and an elevated total pressure and temperature. Such suitable reaction systems can include fixed catalyst bed systems, ebullating catalyst bed systems, slurried catalyst systems, and fluidized catalyst bed systems. The preferred reactor system is that which includes a fixed bed of the inventive catalyst contained within a reactor vessel equipped with a reactor feed inlet means, such as a feed nozzle, for introducing the distillate feedstock into the reactor vessel, and a reactor effluent outlet means, such as an effluent outlet nozzle, for withdrawing the reactor effluent or the treated hydrocarbon product or the ultra-low sulfur distillate product from the reactor vessel.

The hydroprocessing process generally operates at a hydroprocessing reaction pressure in the range of from 689.5 kPa (100 psig) to 13,789 kPa (2000 psig), preferably from 1896 kPa (275 psig) to 10,342 kPa (1500 psig), and, more preferably, from 2068.5 kPa (300 psig) to 8619 kPa (1250 psig).

The hydroprocessing reaction temperature is generally in the range of from 200 °C (392 °F) to 420 °C (788 °F), preferably, from 260 °C (500 °F) to 400 °C (752 °F), and, most preferably, from 320 °C (608 °F) to 380 °C (716 °F).

It is recognized that one of the unexpected features from the use of the inventive composition is that it exhibits higher catalytic activity than certain other alternative catalyst compositions, and, thus, it will, in general, provide for comparatively lower required process temperatures for a given amount of desulfurization or denitrogenation, or both.

The flow rate at which the hydrocarbon feedstock is charged to the reaction zone of the inventive process is generally such as to provide a liquid hourly space velocity (LHSV) in the range of from 0.01 hr ¹ to 10 hr ¹ . The term “liquid hourly space velocity”, as used herein, means the numerical ratio of the rate at which the hydrocarbon feedstock is charged to the reaction zone of the inventive process in volume per hour divided by the volume of catalyst contained in the reaction zone to which the hydrocarbon feedstock is charged. The preferred LHSV is in the range of from 0,05 hr ¹ to 5 hr ¹ , more preferably, from 0.1 hr ¹ to 3 hr ¹ and, most preferably, from 0.2 hr ¹ to 2 hr ¹ .

It is preferred to charge hydrogen along with the hydrocarbon feedstock to the reaction zone of the inventive process. In this instance, the hydrogen is sometimes referred to as hydrogen treat gas. The hydrogen treat gas rate is the amount of hydrogen relative to the amount of hydrocarbon feedstock charged to the reaction zone and generally is in the range upwardly to 1781 m ³ /m ³ (10,000 SCF/bbl). It is preferred for the treat gas rate to be in the range of from 89 m ³ /m ³ (500 SCF/bbl) to 1781 m ³ /m ³ (10,000 SCF/bbl), more preferably, from 178 m ³ /m ³ (1,000 SCF/bbl) to 1602 m ³ /m ³ (9,000 SCF/bbl), and, most preferably, from 356 m ³ /m ³ (2,000 SCF/bbl) to 1425 m ³ /m ³ (8,000 SCF/bbl).

The hydrotreated product yielded from the process of the invention has low or reduced sulfur and nitrogen concentrations relative to the hydrocarbon feedstock.