Catalyst to attain low sulfur gasoline

Abstract

This invention relates to a hydrodesulfurization catalyst, a method for preparing the catalyst, and a method for the preparation of low sulfur gasoline fuel with minimal loss of RON. The catalyst particles include a group VIB metal and a support material having relatively high surface area, and optionally includes one or more group VIIIB metal. The method for preparing the catalyst allows for greater loading of the active metal species on the surface of the support material under aqueous reaction conditions.

Claims

1. A method for hydrodesulfurizing a petroleum based hydrocarbon distillate comprising: contacting the petroleum hydrocarbon distillate with hydrogen gas in the presence of a hydrodesulfurization catalyst, wherein the petroleum hydrocarbon distillate includes sulfur or sulfur impurities; wherein the hydrodesulfurization catalyst consists of an activated carbon catalyst support material, a first metal in oxide form and selected from the group consisting of chromium, molybdenum and tungsten, and a second metal in oxide form and selected from the group consisting of iron, ruthenium, osmium, cobalt, rhenium, iridium, nickel, palladium and platinum, the activated carbon catalyst support material consisting of a basic or neutral activated carbon; wherein the hydrodesulfurization catalyst consists of between about 15 and 30% by weight of the oxide form of the first metal and between about 1 and 10% by weight of the oxide form of the second metal, wherein the molar ratio of the first metal to the second metal is between 1.5:1 and 5:1.

2. The method of claim 1 wherein the hydrodesulfurization catalyst is prepared by the process comprising: preparing a mixture comprising at least one metal salt, a catalyst support and water, wherein the mixture is under vacuum; removing the water from the mixture and collecting the catalyst particles; calcinating the particles by heating the particles to a temperature of greater than about 200 C.; and partially sulfiding the catalyst particles by contacting the calcined catalyst particles with a gas stream comprising up to about 5% by volume hydrogen sulfide; wherein the metal salt comprises a first metal selected from the group consisting of chromium, molybdenum, and tungsten.

3. The method of claim 1 wherein the hydrodesulfurization catalyst consists of about 20% by weight molybdenum and at least about 2% by weight nickel.

4. The method of claim 1 wherein the hydrodesulfurization catalyst consists of about 20% by weight molybdenum and at least about 2% by weight cobalt.

5. The method of claim 1, wherein the petroleum hydrocarbon distillate comprises fluid catalytic cracking (FCC) gasoline, coker naphtha and straight run naphtha.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Gasoline hydrodesulfurization catalysts preferably have high hydrodesulfurization activity and low hydrogenation activity of olefins. Conventional methods for the preparation of nickel-molybdenum (NiMo) or cobalt-molybdenum (CoMo) catalysts supported on activated carbon can result in catalysts having less than about 5% by weight MoO.sub.3, and non-uniform aggregates of the metal oxide. The drawbacks associated with the conventional methods for preparing catalysts on activated carbon limit the catalytic performance in the desulfurization of hydrocarbons, and particular in the desulfurization of catalytically cracked gasoline. Preferably, the metal oxide forms a thin uniform layer on the surface of the support material. Additionally, it is preferred that the metal is present in an amount greater than approximately 15% by weight of the support material to enhance catalytic conversion of sulfur compounds.

(2) Catalyst

(3) The catalyst includes a support material and at least one active metal.

(4) The catalyst support can be selected from activated carbon, activated carbon fiber, carbon black, activated carbon fabric, activated carbon honeycomb, metal oxides including silicon dioxide, titanium dioxide, zirconium dioxide, and the like, and combinations thereof. Activated carbon and carbon black are believed enhance the activity of the metal species due to relatively weak polarity and relatively high surface area. In certain embodiments, the surface area of the support material can be at least about 200 m.sup.2/g. In other embodiments, the surface area can be at least about 300 m.sup.2/g. In preferred embodiments, the surface area can be at least about 500 m.sup.2/g, more preferably at least about 1000 m.sup.2/g. In certain embodiments, the pore diameter can be between about 0.5 nm and 5 nm. In certain other embodiments, the pore diameter can be between about 1.5 nm and 4 nm.

(5) The catalyst composition can at least one active metal selected from Group VIB of the periodic table, which includes, chromium, molybdenum and tungsten. The catalyst can also include at least one promoter metal selected from the Group VIIIB metals of the periodic table, which include iron, ruthenium, osmium, cobalt, rhenium, iridium, nickel, palladium and platinum, as the active component. In certain embodiments, the catalyst composition can include more than one Group VIIIB metal. In a preferred embodiment, the catalyst can include molybdenum. In certain other preferred embodiments the catalyst composition can include either cobalt or nickel. Optionally, at least a portion of the metal can be present as a metal sulfide. Alternatively, at least a portion of the metal can be present as a metal oxide.

(6) The group VIB metal can be present in oxide form and can be loaded onto the support material in an amount exceeding approximately 10% by weight of the support material. In other embodiments, the group VIB metal oxide can be loaded onto the support material in an amount exceeding approximately 15% by weight of the support material. In yet other embodiments, the group VIB metal oxide can be loaded onto the support material in an amount exceeding approximately 20% by weight of the support material. In yet other embodiments, the group VIB metal oxide can be loaded onto the support material in an amount exceeding approximately 25% by weight of the support material. In certain preferred embodiments, the metal oxide can be MoO.sub.3.

(7) The group VIIIB metal can be present in oxide form and can be loaded onto the support in an amount exceeding approximately 1% by weight of the support material. In other embodiments, the group VIIIB metal oxide can be present in an amount between about 1% and 10% by weight of the support material. In other embodiments, the group VIIIB metal oxide can be present in an amount between about 4% and 10% by weight of the support material.

(8) Known catalyst promoters can also be added to the catalyst composition. Exemplary catalyst promoters can include, but are not limited to, boron and phosphorous.

(9) The catalyst composition can be subjected to calcining or similar thermal treatment, which can be beneficial by increasing the thermal stability and metal dispersion of the catalyst composition. Generally, during calcination, the particles are heated in an oxygen containing environment to temperatures ranging from about 200 C.-800 C. The process can be carried out by placing the composition in a process heater, at the desired temperature, with a flowing oxygen containing gas, such as for example, atmospheric air. The process heater can be heated to the designated temperature or temperature range, maintained at the designated temperature for a defined time period, and then cooled to room temperature. The calcination of the catalyst composition can include heating the catalyst particles at a defined ramp rate.

(10) Prior to use, the catalyst can be exposed to a sulfur source for the preparation of surface bound metal sulfides. The sulfur source can be contacted with the catalyst in either liquid or gaseous form. In certain embodiments, the catalyst particles can be contacted with a hydrogen gas mixture that includes hydrogen sulfide. In one exemplary embodiment, the sulfur source is a hydrogen gas stream that can include up to approximately 10% hydrogen sulfide by volume. Alternatively, the hydrogen gas stream includes between approximately 1 and 5% hydrogen sulfide by volume. In certain embodiments, the catalyst particles can be contacted with a sulfur source at a temperature of greater than about 200 C., preferably at temperatures greater than about 300 C.

(11) Catalyst Preparation

(12) In another aspect, a method for preparing a hydrodesulfurization catalyst composition from an aqueous solution is provided. Generally, activated carbon species are hydrophobic. Thus, preparation of catalysts using activated carbon supports generally requires the use of organic solvents to reduce hydrophobicity of the carbon support surface, or to enhance the affinity of the metal species to the surface of the activated carbon. Methods of preparing catalysts employing carbon supports from aqueous solutions generally result in low catalyst loading. A catalytic support material can be placed under vacuum to facilitate the removal of trapped solvent and/or moisture. In certain embodiments, the catalytic support material can be heated under vacuum. Exemplary conditions for the catalyst preparation include heating the catalytic support material to a temperature of up to about 100 C. and applying vacuum up to a pressure of approximately 1 torr or less. Without being bound to any specific theory, it is believed that treating the catalytic support material under vacuum can facilitate diffusion of the metal species into the small pores.

(13) A mixture can be prepared by adding a metal salt solution that includes at least one metal salt and water, to the support under vacuum. The metal salt solution can be added to the catalyst support material slowly. Optionally, in certain embodiments, it may be advantageous that the metal salt solution is added dropwise to the catalyst support material.

(14) Exemplary catalytic support materials can include, but are not limited to, activated carbon, activated carbon fiber, carbon black, activated carbon fabric, activated carbon honeycomb, metal oxides including silicon dioxide, titanium dioxide, zirconium dioxide, and the like, and combinations thereof. In a preferred embodiment, the catalyst support material is an activated carbon species.

(15) In certain preferred embodiments, the catalyst support material can be neutral or basic, when compared to the gamma-type alumina, which is frequently used as the support material for desulfurization catalysts. For use in the desulfurization of hydrocarbon streams, in particular catalytically cracked gasoline, which can typically include olefins and produce hydrogen sulfide as a product of the hydrodesulfurization, the catalyst support material is preferably not acidic. Without wishing to be bound by any theory, it is believed that acidic sites on a support material can facilitate olefin saturation, which can result in RON loss, and recombination of hydrogen sulfide with olefin, which limit attainable sulfur content of product. Any RON loss must then be compensated for by the addition of expensive alkylates, isomerates and/or other chemicals.

(16) Catalyst support materials having a high surface area allow for greater loading of the active species which provide the catalytic activity. Thus, catalyst support materials having a relatively high surface area are preferred. In other embodiments, the catalyst support material surface area can be at least about 200 m.sup.2/g. In certain embodiments, the catalyst support material surface area is at least about 300 m.sup.2/g. Preferably, the catalyst support material surface area is at least about 500 m.sup.2/g. Even more preferably, the catalyst support material has a surface area of at least about 1000 m.sup.2/g.

(17) The catalyst support material particles can have a diameter of between about 0.5 and 10 mm, preferably between about 1 and 8 mm in diameter, and even more preferably approximately 5 mm in diameter. In certain other embodiments, the catalyst support material particles can have a pore diameter of less than about 15 nm. In yet other embodiments, the catalyst support material particles can have a pore diameter of less than about 10 nm.

(18) Exemplary catalyst support materials having low acidity and high surface area include activated carbon species. Activated carbons are exemplary catalyst support materials that can be advantageously used to prepare hydrodesulfurization catalysts, according to the methods described herein.

(19) Exemplary metal salts can include salts of the Group VIB metals of the periodic table, which include chromium, molybdenum and tungsten. In certain embodiments, exemplary metal salts can include salts of the VIIIB metals, which include iron, ruthenium, osmium, cobalt, rhenium, iridium, nickel, palladium and platinum. In certain embodiments, the metal salt includes a metal that is preferably selected from cobalt, molybdenum and nickel. In other embodiments, more than one metal salt can be added to the solution, wherein at least one of the metals is selected from cobalt, molybdenum and nickel. Preferably, the metal salt(s) and catalyst support material are sufficiently mixed to produce a homogeneous aqueous solution that contains the metal salt and the support material. Specific examples of metal salts which can be employed according to the methods disclosed herein include, but are not limited to, (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O, Ni(NO.sub.3).sub.2.6H.sub.2O, Co(NO.sub.3).sub.2.6H.sub.2O, NiCl.sub.2.6H.sub.2O, CoCl.sub.2.6H.sub.2O, (NH.sub.4).sub.6H.sub.2W.sub.12O.sub.40.XH.sub.2O (ammonium metatungstate), and the like. Nickel and cobalt acetates can also be used as precursors, although, for purposes of solubility, organic solvents may be required. Optionally, finely ground particles of molybdenum trioxide can also be used to prepare a colloidal precursor solution.

(20) The mixture can be mechanically mixed to ensure adequate interaction between the catalyst support material and the metal salts. Mixing can be accomplished by known means, such as for example, by ultrasonic vibration, by mechanical stirring means, or other means known in the art. In certain embodiments, a mixture that includes water, catalyst support material and the metal salt can be mixed for at least about 15 minutes. In other embodiments, the mixture can be mixed for a period of at least about 1 hour. In yet other embodiments, the mixture can be mixed for a period of between about 4 and 6 hours.

(21) After mixing, the mixing vessel can be exposed to atmospheric conditions and the water can be removed. Optionally, the mixture can be heated to assist in the evolution of water and gases. In certain other embodiments, the solids can be collected by filtration. In certain preferred embodiments, the mixture can be first heated, followed by removal of the remained of the liquids under vacuum. In other embodiments, the mixture is heated to a temperature of between about 40 C. and 150 C., preferably between about 60 C. and 130 C. In certain embodiments, the mixture is heated to a temperature of greater than about 100 C. In certain other embodiments, the mixture is heated to a temperature of approximately 120 C. In certain embodiments, the mixture is stirred while the catalyst is heated. In certain embodiments, liquids can be removed under a vacuum of up to about 1 torr. In certain preferred embodiments, remaining liquids can be removed under a vacuum of approximately 1 torr, for a period of approximately 16 hours.

(22) The particles can be calcinated after collection and drying at a temperature of between about 200 C. to 600 C. In certain embodiments, the catalyst particles are calcinated at a temperature between about 200 C. and 500 C. In preferred embodiments, the catalyst particles are calcinated at a temperature of between about 250 C. and 350 C. Optionally, the catalyst particles can be calcinated at a temperature of approximately 300 C. The catalyst particles can be calcinated for between about 30 minutes and 8 hours, preferably for between 3-6 hours. In an exemplary embodiment, the catalyst particles are calcinated at a temperature of approximately 320 C. for a period of approximately 3 hours. Optionally, calcination can be done in an oxygen containing environment, preferably in air. Without being bound to any theory, calcination in air is believed to form the oxidic precursor form of the metal as the active phase of the catalyst.

(23) After being dried and collected, the catalyst particles can be contacted with a sulfur containing source. The sulfur containing source can be a gas or liquid source. In certain embodiments, the catalyst particles can be contacted with a hydrogen gas mixture that includes hydrogen sulfide. Optionally, the sulfur source is a hydrogen gas stream which can include up to approximately 10% hydrogen sulfide by volume. Alternatively, the hydrogen gas stream includes between approximately 1 and 5% hydrogen sulfide by volume. In certain embodiments, the catalyst particles can be contacted with a sulfur source at a temperature of greater than about 100 C., preferably at temperatures greater than about 200 C., and most preferably at a temperature greater than about 300 C. In an exemplary embodiment, the catalyst particles can be contacted with a sulfur containing source at a temperature of approximately 360 C. Preferably, the sulfur containing hydrogen gas can contact the catalyst particles for an extended period of time, such as for example, at least one hour, or more preferably, at least two hours. The effluent leaving the catalyst during pre-sulfiding has sulfur content lower than that of the effluent being fed, thus showing active sulfidation of the oxidic form of the catalyst particles.

(24) Catalytic Desulfurization

(25) In one aspect, a method of producing a reduced sulfur gasoline is provided.

(26) The method includes the steps of contacting a gasoline feedstock prepared by the catalytic cracking gasoline with a desulfurization catalyst wherein the desulfurization catalyst includes an activated carbon support having one or more of a Group VIB and a Group VIIIB metal sulfide adsorbed on the surface.

(27) The hydrocarbon feedstock can be a derivative from crude petroleum oil, oil sands, oil shale, or oil derived from coal or wood. Generally, any hydrocarbon oil that includes sulfur or sulfur impurities, can be used as a suitable hydrocarbon feedstock. Typically, modern gasoline is a blend of several different refinery streams, including reformate, straight run naphtha, catalytically cracked gasoline, coker naphtha, isomerate, alkylate and oxygenate. The main source of sulfur content typically comes from FCC gasoline, coker naphtha and straight run naphtha obtained from high sulfur crudes.

(28) Desulfurization can take place in a reactor, such as for example, a fixed bed, packed bed, slurry bed or fluidized bed reactor, which can be charged with an activated carbon supported desulfurization catalyst, which can be prepared as described herein. Typically, the gasoline feedstock, hydrogen gas and the catalyst are contacted in a reactor, typically at an elevated temperature. The desulfurization can take place at a temperature of at least about 200 C. In certain embodiments, the desulfurization takes place at a temperature of between about 250 C. and 400 C. Typically pressures can be between about 100 and 500 psig. The LHSV can be between about 2 and 10 h.sup.1, preferably between approximately 4 and 8 h.sup.1. The ratio of hydrogen gas to feedstock can be from about 20-200 L/L, preferably from about 50-150 L/L, more preferably approximately 110-130 L/L.

(29) The overall process can include multiple reactors arranged in parallel. This arrangement allows for continuous operation of the desulfurization process while allowing for the simultaneous regeneration of spent catalyst.

(30) The process and catalyst described herein are advantageously solid heterogeneous catalysts. Because the catalyst is a heterogeneous catalyst, there is no need to determine suitable organic solvents for solubility of the catalyst and hydrocarbonaceous feedstock. Additionally, because the catalyst is a solid material, and dissolution of catalyst in reaction matrix is not an important aspect of the desulfurization, there is never any need to separately remove solvent or dissolved catalyst from the effluent.

EXAMPLES

(31) Example 1 provides a method for the preparation of an exemplary hydrodesulfurization catalyst that includes molybdenum and cobalt on an activated carbon support. An HCN (heavy cat naphtha) fraction distilled from a FRCN (full range cat naphtha) is treated with the hydrodesulfurization catalyst prepared according to the procedure described in Example 1. Example 2 describes the hydrodesulfurization of an HCN fraction distilled from a FRCN with a commercially available desulfurization catalyst. The results are compared in Table 6.

Example 1

(32) A 20.0 g sample of dried and purified activated carbon (Norit) having specific surface area of 1,065 m.sup.2/g and average pore diameter of 2.2 nm was placed in a 200 mL flask. The flask was then evacuated under vacuum for approximately 16 hours to a pressure of approximately 1 torr. An aqueous solution was prepared by dissolving 4.91 g (0.00397 mol) of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O (Fluka) to make 20 mL (0.20 M) aqueous solution. The aqueous solution (20 mL) was added dropwise and shaken over a period of about 5 minutes into the flask, which was maintained under vacuum, and mixed for approximately 6 hours. Following mixing, the flask was vented to the atmosphere and heated at a temperature of approximately 120 C. until the atmospheric vaporization of water ceased. The flask was cooled to room temperature and evacuated under vacuum to a pressure of approximately 1 torr for approximately 16 hours.

(33) An 8.02 g (0.00649 mol) sample of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O (Fluka) was dissolved in water to make 40 mL (0.16 M) aqueous solution. A 20 mL sample of the aqueous solution was introduced to the flask dropwise over about a 5 minute period with shaking, under vacuum, and mixed for approximately 6 hours. The flask was vented to atmosphere and to a temperature of approximately 70 C. until the atmospheric vaporization of water ceased. The flask was cooled to room temperature and evacuated under vacuum to a pressure of approximately 1 torr for approximately 16 hours again.

(34) A 7.06 g (0.0243 mol) sample of Co(NO.sub.3).sub.2.6H.sub.2O (Aldrich Chem.) was dissolved in water to make a 20 mL aqueous solution (1.2 M). The aqueous solution (20 mL) was introduced to the flask dropwise over about a 5 minute period with shaking, under vacuum, and mixed for approximately 6 hours. After mixing, the flask was vented to atmosphere and heated to a temperature of approximately 70 C. until the atmospheric vaporization of water ceased. The contents of the flask, a black powder, was transferred to an alumina crucible, heated at a rate of approximately 2 C./min to about 320 C. and calcinated for approximately 3 hours under atmosphere. The catalyst product (29 g) was collected as a black particulate material, consisting of approximately 25 wt % molybdenum oxide and 6.2 wt % cobalt oxide.

(35) A full range cat naphtha (FRCN) feedstock was distilled to produce a heavy cat naphtha (HCN) stream. Properties of feedstocks are outlined in Table 1.

(36) TABLE-US-00001 TABLE 1 FRCN HCN A Total Sulfur (ppm) 2467 665 Total Nitrogen (ppm) 19 6 Composition, wt % (ASTM-D5134) Aromatics 22.2 36.2 I-Paraffins 27.3 26.9 Napthenes 14.2 17.1 n-Olefins 10.7 6.1 I-Olefins 12.0 4.6 Cyclic-Olefins 1.5 0.5 Total Olefins 23.5 13.4 Paraffins 5.5 4.3 Unidentified 4.0 2.1 Distillation (ASTM-D2887) ( C.) 5% 39 91 10% 46 99 20% 57 112 40% 85 127 50% 103 141 70% 143 153 90% 191 173

(37) The HCN A catalyst described in Table 1 above was hydrotreated with approximately 10 mL of the catalyst, prepared as described above, which was pre-sulfided at 320 C. for 12 hours with straight run naphtha spiked with dimethyldisulfide to have a sulfur content of approximately 2.5 wt %. Operating conditions for hydrotreatment of HCN are summarized in Table 2.

(38) TABLE-US-00002 TABLE 2 Run 29 Run 30 Run 31 Pressure (psig) 300.0 300 300 Temperature ( C.) 280 300 341 LHSV (h.sup.1) 6.1 5.8 6.0 H.sub.2/Oil (L/L) 119 119 119

(39) The liquid products from Runs 29, 30 and 31 were analyzed as shown in Table 3.

(40) TABLE-US-00003 TABLE 3 Liquid Liquid Liquid Product Product Product from Run 29 from Run 30 from Run 31 Total Sulfur (ppm) 90 30 7 Total Nitrogen (ppm) 1.7 1.5 1.7 RON Loss 4.5 5.2 9.7 Distillation (ASTM D2887) 5% 91 87 84 10% 96 98 92 20% 105 112 104 40% 123 128 120 50% 132 138 129 70% 150 156 148 90% 171 172 169

Example 2

(41) The HCN A described in Table 1 above was hydrotreated with approximately 10 mL of a commercially available Cobalt/Molybdenum hydrotreating catalyst having an alumina support and a surface area of approximately 250 m.sup.2/g. The catalyst was pre-sulfided at 320 C. for approximately 12 hours with straight run naphtha spiked with dimethyldisulfide to have 2.5 wt % sulfur. The operating conditions for hydrotreatment of the HCN fraction are summarized in Table 4.

(42) TABLE-US-00004 TABLE 4 Run 4 Run 5 Run 6 Pressure (psig) 300 300 300 Temperature ( C.) 260 300 330 LHSV (h.sup.1) 6.1 6.1 6.0 H.sub.2/Oil (L/L) 118 118 118

(43) Liquid products from Run 4, 5 and Run 6 were analyzed as shown in Table 5.

(44) TABLE-US-00005 TABLE 5 Liquid Product Liquid Product Liquid Product from Run 4 from Run 5 from Run 6 Total Sulfur (ppm) 571 216 55 Total Nitrogen (ppm) 2.4 1.4 1.3 RON Loss 0.6 1.7 5.8 Distillation (ASTM D2887) ( C.) 5% 89 89 87 10% 96 97 94 20% 105 108 104 40% 122 126 120 50% 130 136 129 70% 148 153 147 90% 169 172 168

(45) The results are presented in comparative form below, wherein the hydrodesulfurization temperatures, resulting sulfur content and percent (%) conversion for the desulfurization of HCN using a the catalyst prepared according to Example 1 (corresponding to Tables 2 and 3, Runs 29, 30 and 31) and the commercially available hydrotreating catalyst prepared according to Example 2 (corresponding to Tables 4 and 5, Runs 4, 5 and 6).

(46) TABLE-US-00006 TABLE 6 Hydrotreatment with Catalyst Prepared Hydrotreatment with Commercially According to Example 1 Available Catalyst Accordin to Example 2 Temp. ( C.) Sulfur (ppm) % Conversion Temp. ( C.) Sulfur (ppm) % Conversion 280 90 86.5 260 571 14.2 300 30 95.4 300 216 67.5 341 7 98.9 330 55 91.7

(47) As shown in the above tables and summarized in Table 6, hydrotreatment of HCN with the catalyst prepared according to the methods described in Example 1 resulted in a HCN product stream having much lower sulfur contents than the product stream from hydrotreatment with a commercially available alumina supported catalyst. Hydrotreatment at a temperature of 300 C. with the catalyst of Example 1 achieved an HCN product stream having approximately 30 ppm sulfur while similar hydrotreatment with the commercially available alumina supported catalyst of Example 2 produced an HCN product stream having approximately 216 ppm sulfur. Those particular sulfur contents correspond to sulfur conversions of approximately 95.4% and 67.5%, respectively. Desufurization with the commercially available alumina supported catalyst of Example 2 resulted in a sulfur conversion of approximately 91.9% 340 C. In contrast, ultra deep sulfur conversion was achieved with the catalyst prepared according to Example 1 during hydrotreatment at a temperature of approximately 341 C., wherein the process resulted in a sulfur conversion of approximately 98.9%, and produced a product stream having a sulfur content of approximately 7 ppm.

(48) Loss of RON, estimated by PIONA data, was less for desulfurization with the catalyst of Example 1 than with the commercially available alumina supported catalyst of Example 2 for relatively similar conversion rates. For example, the catalyst of Example 1 had an RON loss of approximately 5.2 at 97.5% sulfur conversion (Run 30, 300 C.) and an RON loss of approximately 9.7 at 98.9% sulfur conversion (Run 31, 341 C.). In contrast, the commercially catalyst of Example 2 had an RON loss of approximately 5.8 at 91.9% sulfur conversion (Run 6, 330 C.). Thus, it is shown that the catalyst prepared according to Example 1 can achieve higher conversion (95.4% desulfurization vs. 91.7% desulfurization), at less severe conditions (300 C. vs. 330 C.), and a lower loss of RON (5.2 vs. 5.8). In addition, it is shown that the catalyst prepared according to Example 1 can achieve much higher sulfur conversion than the commercially available catalyst of Example 2 under severe reaction conditions (98.9% conversion corresponding to a sulfur content of 7 ppm at a desulfurization temperature of 341 C. vs. 91.7% conversion corresponding to a sulfur content of 55 ppm at 330 C.).

(49) As used herein, the terms about and approximately should be interpreted to include any values which are within 5% of the recited value. Furthermore, recitation of the term about and approximately with respect to a range of values should be interpreted to include both the upper and lower end of the recited range.

(50) While the invention has been shown or described in only some of its embodiments, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.