HYDROCONVERSION PROCESS USING A SULFIDED MOLYBDENUM CATALYST CONCENTRATE

Abstract: A process for converting a heavy hydrocarbonaceous chargestock to lower boiling products which process comprises reacting the chargestock with a catalyst concentrate in the presence of hydrogen, at hydroconversion conditions, said catalyst concentrate having been prepared by the steps comprising: (a) forming a precursor catalyst concentrate by mixing together: (i) a hydrocarbonaceous oil comprising constituents boiling above about 570 DEG C; (ii) a metal compound, said metal being selected from the group consisting of Groups II, III, IV, V, VIB, VIIB and VIII of the Periodic Table of the Elements, in an amount to provide from about 0.2 to 2 wt. % metal, based on said hydrocarbonaceous oil; and (b) heating the precursor concentrate to an effective temperature to produce a catalyst concentrate, wherein elemental sulfur is used as the sulfiding agent in an amount such that the atomic ratio of sulfur to metal is from about 1/1 to 8/1.

Description: HYDROCONVERSION PROCESS USING A SULFIDED MOLYBDENUM CATALYST CONCENTRATE FIELD OF THE INVENTION This invention relates to a hydroconversion process for converting a heavy hydrocarbonaceous feedstock to lower boiling products, which process involves the use of a sulfided catalyst concentrate which is prepared by use of elemental sulfur as the sulfϊding source. BACKGROUND OF THE INVENTION There is substantial interest in the petroleum industry for converting heavy hydrocarbonaceous feedstocks to lower boiling liquids. One type of process suitable for hydroconversion of heavy feedstocks is a slurry process using a catalyst prepared in a hydrocarbon oil from a thermally-decomposable, metal compound catalyst precursor. The catalyst is formed in situ in the hydroconversion zone. Further, U.S. Patent Nos. 4,740,295 and 4,740,489, both of which are incorporated herein by reference, teach a method wherein the catalyst is prepared from a phosphomolybdic acid precursor concentrate. The precursor concentrate is sulfided prior to the final catalyst formation. This presulfiding step is taught to produce a catalyst having greater control over coke formation. The sulfϊding agent in these two patents requires a hydrogen-sulfide containing gas or a hydrogen-sulfide precursor and the resulting catalyst concentrate is used for hydroconversion of heavy hydrocarbonaceous materials to lower boiling products. The term "hydroconversion" with reference to a hydrocarbo¬ naceous oil, is used herein to designate a catalytic process conducted in the presence of hydrogen in which at least a portion of the heavy constituents of the oil is converted to lower boiling products. The simultaneous reduction of the concentration of nitrogenous compounds, sulfur compounds and metallic constituents of the oil may also result. All boiling points referenced herein are atmospheric pressure equivalent boiling points unless otherwise specified. It has been found that introducing a catalyst precursor as a concentrate in a hydrocarbonaceous oil into a hydroconversion zone containing a heavy hydrocarbonaceous chargestock has certain advantages when compared with a process wherein the catalyst precursor is introduced into the hydrocon¬ version zone without first forming a concentrate; that is, by introducing the catalyst precursor directly into the feed in the reactor. The advantages include: (i) ease of mixing the precursor with a small stream instead of the whole feed; (ii) the ability to store the precursor concentrate for future use and/or activity certification; and (iii) the ability to use a hydrocarbonaceous oil, other than the feedstock, as dispersing medium for the catalyst precursor, which hydrocarbonaceous oil other than the feedstock can be more optimum for developing catalyst activity- Further, it has also been found that converting a catalyst precursor concentrate to a catalyst concentrate comprised of solid catalyst particles dispersed in the hydrocarbonaceous oil and subsequently introducing a portion of this catalyst concentrate into the hydrocarbonaceous chargestock to be hydroconverted, with or without coal, will provide certain additional advantages, such as greater flexibility of conditions. Such advantages include: (i) use of higher concentrations of sulfiding agent than those concentrations that could practically be used to treat the total chargestock; (ii) flexibility of heat balance; and (iii) economy of energy. Treatment of only the catalyst precursor concentrate to produce the catalyst instead of treating the entire feedstock containing the catalyst precursor permits reduction of equipment size. Furthermore, preparing a catalyst concentrate permits storage of the catalyst concentrate for use as needed on-site or to send to another site. It has also been found, and is claimed herein, that when elemental sulfur is used as the sulfiding agent in the preparation of the catalyst concentrate of this invention a critical range of atomic ratio of sulfur to metal of the metal compound exits. This critical range is from about 1/1 to 8/1 sulfur to metal. Use of elemental sulfur has the advantages of ease and simplicity of catalyst preparation. It also has the advantage of being less hazardous because there is no need to handle hydrogen sulfide under elevated pressures, as is required by prior art processes. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a process for hydroconverting a heavy hydrocarbonaceous chargestock to lower boiling products, which process comprises reacting the hydrocarbonaceous chargestock with a catalyst in the presence of hydrogen at hydroconversion conditions, said catalyst having been prepared by a method which comprises: (a) forming a catalyst precursor concentrate by mixing together: (i) a hydrocarbonaceous oil comprising constituents boiling above about 1050°F; (ii) a metal compound, said metal being selected from the group consisting of Groups IVB, VB, VIB, VHB and VIII of the Periodic Table of the Elements, in an amount to provide from about 0.2 to 2 wt% metal, based on said hydrocarbonaceous oil; (b) heating the mixture to an effective temperature to produce the catalyst concentrate; wherein elemental sulfur is used as a presulfiding agent in an amount such that the atomic ratio of sulfur to metal is from about 1/1 to 8/1. In preferred embodiments of the present invention, the metal compound is an aqueous solution of phosphomolybdic acid and a drying step is performed before the catalyst precursor is introduced into the heating zone. In other preferred embodiments of the present invention, the hydrocarbonaceous oil of step (i)(a) is a blend of a lighter oil with at least 10 wt% heavier oil, said lighter oil boiling below about 570°C and said heavier oil boiling above about 570°C. In still another preferred embodiment of the present invention, the elemental sulfur is added as a concentrate in hydrocarbonaceous oil and is added to the precursor concentrate: (i) prior to the introduction of the precursor into the heating zone of step (b) or (ii) in the heating zone. BRIEF DESCRD7TION OF THE FIGURES Figure 1 is a schematic flow plan of one embodiment of the present invention. Figure 2 is a plot of toluene insoluble coke yield on 520 +o C feed and 520 +o C conversion versus S/Mo atomic ratios in the catalyst concentrate for the catalyst materials of this invention when tested as hydroconversion catalysts. Figure 3 is a plot of toluene insoluble solid yield versus performing temperature (heating) used in forming the catalyst concentrates of this invention when tested under hydroconversion conditions. DETAILED DESCRDTTION OF THE INVENTION Figure 1 hereof represents one of the preferred embodiments for carrying out the instant invention wherein an aqueous solution of phosphomolybdic acid is used as the metal compound. The term "phosphomolybdic acid" is used herein to designate aqueous solutions of the reaction product of Mo0 3 with dilute phosphoric acid in which the phosphorus to molybdenum atomic ratio ranges from 0.083 to 2, preferably from 0.083 to 1 and most preferably from 0.083 to 0.5. Said solutions can contain one or more phosphomolybdic acid species such as the 12-molybdophosphoric acid and the dimeric 18-molybdophosphoric acid. Moreover, the crystalline 12 and 18 acids can be used to prepare the water solutions of phosphomolybdic acid used in the process of this invention. If such crystalline phosphomolybdic acids are used, additional H 3 P0 4 or other phosphorus compounds may be added to the solution to provide the desired P/Mo ratio. Phosphomolybdic acids are described in Topics In Current Chemistry No. 76. published by Springer- Verlag of New York, pp. 1-64. 1978; which is incorporated herein by reference. Referring now to Figure 1 hereof, a heavy hydrocarbonaceous oil is introduced by line 10 into mixing zone 1. Suitable hydrocarbonaceous oils for introduction into mixing zone 1 include hydrocarbonaceous oils comprising constituents boiling above 570°C, preferably having at least 10 wt% constituents boiling above 570°C, such as crude oils, atmospheric residua boiling above 330°C, and vacuum residua boiling above 570°C. Preferably, the hydrocarbonaceous oil has an initial boiling point above at least 330°C and comprises asphaltenes and/or resins. Most preferably, the hydrocarbonaceous oils comprise a lighter boiling oil boiling below about 570°C and a heavier oil boiling above about 570°C in a blend comprising at least about 22 wt% materials boiling above 570°C. Preferred concentrations of the 570 +o C fraction in the blend include from about 22 to 85 wt% heavier oil, more preferably from about 30 to 85 wt% heavier oil, still more preferably about 40 to 85 wt% heavier oil and, most preferably about 45 to 75 wt% heavier oil, based on the total weight of the blend (mixture of oils). The light oil may be a gas oil and heavier oil may be a vacuum residuum. Alternatively, an atmospheric residuum having the appropriate amount of desired constituents may be used as the oil of line 10. The hydrocarbonaceous oil carried by line 10 may be derived from any source, such as petroleum, tar sand oil, shale oil, liquids derived from coal liquefaction processes and mixtures thereof. Generally, these oils have a ■ Conradson carbon content ranging from about 5 to about 50 wt% (as to Conradson carbon, see ASTM test D-189-65). Elemental sulfur, either as the sublimed powder or as a concen¬ trated dispersion of sublimed powder, such as commercial Flowers of sulfur, in heavy hydrocarbonaceous oil, is introduced into mixing zone 1 by line 12. Allotropic forms of elemental sulfur, such as orthorhombic and monoclinic sulfur are also suitable for use herein. The preferred physical form of sulfur is the sublimed powder (flowers of sulfur), although sulfur may also be introduced as molten sulfur and as sulfur vapor. The amount of sulfur added into mixing zone 1 is such that the atomic ratio of sulfur to molybdenum is from about 1/1 to 8/1, preferably from about 2/1 to 7/1 and, more preferably from about 3/1 to 6/1. Alternatively, sulfur can be added at any point in the catalyst concentration preparation procedure as long as it is not contacted with an aqueous solution prior to being introduced into oil. For example, it can be added as a concentrate in a hydrocarbonaceous oil after the precursor concentrate has been dried. It can also be introduced into the heating zone during formation of the catalyst concentrate. If the elemental sulfur is added as a concentrate in oil, the amount of sulfur in the concentrate is such that it still meets the aforementioned requirements pertaining to atomic ratio of sulfur to metal. That is,, the atomic ratio of sulfur to metal of the metal compound will remain 1/1 to 8/1. The mixture from mixing zone ' 1 is passed to mixing zone 2 via line 14 where an appropriate metal compound, such as an aqueous solution of phosphomolybdic acid (catalyst precursor) is also introduced via line 16. A sufficient amount of the aqueous phosphomolybdic acid solution is introduced into mixing zone 2 to provide from about 0.2 to 2 wt%, preferably from about 0.2 to 1 wt%, more preferably 0.3 to 1 wt% molybdenum from the phosphomolybdic acid, calculated as elemental molybdenum based on the hydrocarbonaceous oil. The resulting mixture is a water-containing catalyst precursor concentrate (i.e., wet catalyst precursor concentrate). The wet catalyst precursor concentrate is removed from mixing zone 2 by line 18 and passed to drying zone 3 in which water is removed from the wet catalyst precursor concentrate by any suitable manner. Such a suitable manner includes heating the water-containing catalyst precursor concentrate to a temperature sufficient to vaporize the water, for example, at a temperature ranging from 100 to 150°C. The water is removed from drying zone 3 by line 20. The dried catalyst precursor concentrate is removed from drying zone 3 and is passed via line 22 to heating zone 4. In heating zone 4, the dried catalyst precursor concentrate is heated, in the absence of added hydrogen, to a temperature of at least about 275°C, preferably at a temperature ranging from about 275°C to about 425°C, more preferably from about 315°C to about 410°C and, most preferably from 330°C to about 400°C. The total pressure in heating zone 4 will range from about 0 psig to about 500 psig, preferably from about 0 psig to about 100 psig. The precursor concentrate is heated for an effective amount of time. By "effective amount of time" we mean that amount of time needed to convert the catalyst precursor to the corresponding catalyst concentrate. Zone 4 may be considered a catalyst formation zone in which the sulfur-containing catalyst precursor concentrate of phosphomolybdic acid is converted to the solid molybdenum-containing catalyst concentrate. The catalyst concentrate is removed from heating zone 4 by line 24. At least a portion of the catalyst concentrate is introduced, via line 25, into line 26 which carries a carbonaceous chargestock comprising a hydro¬ carbon which may have the same boiling point range as the hydrocarbonaceous oil of line 10. The hydrocarbon may also comprise a single hydrocarbon (e.g., tetralin) or a mixture of hydrocarbons having the same, or different, boiling point range as the hydrocarbonaceous oil of line 10 or a different boiling point range from the hydrocarbonaceous oil of line 10. The carbonaceous chargestock may be a hydrocarbonaceous oil or coal in a hydrocarbon diluent. Suitable hydrocarbonaceous oil chargestocks include crude oils; mixtures of hydrocarbons boiling above 220°C, preferably above 340°C; for example, gas oils, vacuum residua, atmospheric residua, once-through coker bottoms and asphalt. The hydrocarbonaceous oil chargestock may be derived from any source, such as petroleum, shale oil, tar sand oil, oils derived from coal liquefaction processes, including coal liquefaction bottoms and mixtures thereof. Preferably, the hydrocarbonaceous oils have at least 10 wt% materials boiling above 570°C. More preferably, the hydrocarbonaceous oils have a Conradson carbon content ranging from about 5 to about 50 wt%. Coal may be added to any of these oils. Alternatively, slurries of coal in a hydrocarbon diluent may be used as chargestock to convert the coal (i.e., coal liquefaction). The diluent may be a single type of hydrocarbon or a mixture of hydrocarbons and may be a light hydrocarbon or a heavy hydrocarbon, as described in U.S. Patent No. 4,094,765, column 1, lines 54 to column 2, line 43, the teaching of which is hereby incorporated herein by reference. When the chargestock, into which at least a portion of the catalyst concentrate is introduced, is an oil, the concentrate disperses in the oil. If the chargestock comprises coal in a diluent, the concentrate may be added to the diluent before, after, or simultaneously with the addition of coal to the diluent. A hydrogen-containing gas is introduced by line 27 into line 26. The mixture of carbonaceous chargestock, catalyst concentrate and hydrogen is passed into slurry hydroconversion zone 5. The catalyst concentrate of line 25 is added to the carbonaceous chargestock in an amount sufficient to provide from about 10 to about 2000 wppm, preferably from about 50 to 1000 wppm, more preferably from about 50 to 800 wppm molybdenum and, most preferably from about 50 to 300 wppm metal, calculated as the elemental metal, preferably molybdenum, based on the total hydroconversion zone chargestock, i.e., concentrate plus carbonaceous chargestock. Suitable hydroconversion operating conditions are summarized below. Conditions Broad Range Preferred Range Temperature, °C 340 to 480 440 to 465 H 2 Partial Pressure, psig 50 to 5000 100 to 2500 The hydroconversion zone effluent is removed by line 28 and passed to a gas-liquid separation zone 6 wherein the normally gaseous phase is separated from a normally liquid phase. The gaseous phase is removed from separation zone 6 by line 30. Alternatively, the gaseous phase, which comprises hydrogen, may be recycled by line 32, preferably after removal of undesired constituents, to slurry hydroconversion zone 5 via line 27. The normally liquid phase, which comprises the molybdenum-containing catalytic solids and a hydroconverted hydrocarbonaceous oil product, is passed by line 34 to separation zone 7 for fractionation by conventional means, such as distillation into various fractions; such as light, medium boiling, and heavy bottoms fractions. The light fraction is removed by line 36. The medium boiling fraction is removed by line 38. The heavy bottoms fraction is removed by line 40 and, if desired, at least a portion of the bottoms fraction may be recycled to the hydroconversion zone. Furthermore, if desired, the catalytic solids may be separated from the hydroconverted oil product and the separated solids may be recycled to the hydroconversion zone. In a broader aspect of the instantly-claimed invention, a metal compound (catalyst precursor), other than an aqueous solution of phosphomolybdic acid, is introduced into one or both of the mixing zones. Of course, if an aqueous solution is not used, there is no need for the drying step. The metal compound may be a compound or mixture of compounds as finely divided solids, or a compound or mixture of compounds as finely divided solids mixed with an organic liquid that is soluble in said hydrocarbonaceous oil, a compound or mixture of compounds that is soluble in the hydrocarbonaceous oil or a compound that is soluble in an organic compound (liquid medium) that can be dispersed in the hydrocarbonaceous oil. It can also be a compound that is water soluble and the resulting aqueous solution dispersed in the hydrocarbonaceous material. For example, the metal compound may be in a phenolic medium, in water, in alcohol, etc. Suitable metal compounds convertible (under preparation conditions) to solid, metal- containing catalysts include: (1) inorganic metal compounds such as carbonyls, halides, oxyhalides; polyacids such as isopolyacids and heteropolyacids (e.g., phosphomolybdic acid, and molybdosilicic acid); (2) metal salts of organic acids such as acyclic and cyclic aliphatic carboxylic acids and thiocarboxylic acids containing two or more carbon atoms (e.g., naphthenic acids); aromatic carboxylic acids (e.g., toluic acid); sulfonic acids (e.g., toluenesulfonic acid); sulfinic acids; mercaptans; xanthic acids; phenols, di- and polyhydroxy aromatic compounds; (3) organometallic compounds such as metal chelates, e.g., with 1,3-diketones, ethylenediamine, ethylenediaminetetraacetic acid, phthalocyanines, etc.; (4) metal salts of organic amines such as aliphatic amines, aromatic amines and quaternary ammonium compounds. The metal constituent of the metal compound that is convertible to a solid, non-colloidal, metal-containing catalyst is selected from the group consisting of Groups IVB, VB, VIB, V B and VHI and mixtures thereof of the Periodic Table of the Elements. The Periodic Table of the Elements referred to herein is published by Sergeant-Welsh Scientific Company being copyrighted in 1979 and available from them as Catalog Number S- 18806. Non-limiting examples include zinc, antimony, bismuth, titanium, cerium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, rhenium, iron, cobalt, nickel and the noble metals including platinum, iridium, palladium, osmium, ruthenium and rhodium. The preferred metal constituent of the metal compound is selected from the group consisting of molybdenum, tungsten, vanadium, chromium, cobalt, titanium, iron, nickel and mixtures thereof. Preferred compounds of the given metals include the salts of acyclic (straight or branched chain) aliphatic carboxylic acids, salts of cyclic aliphatic carboxylic acids, polyacids, carbonyls, phenolates and organoamine salts. Such metal compounds are described in U.S. Patent No. 4,295,995, the teachings of which are incorporated herein by reference. The preferred metal compounds are inorganic polyacids of metals selected from Groups VB, VIB and mixtures thereof, that is, vanadium, niobium, chromium, molybdenum, tungsten and mixtures thereof. Suitable inorganic polyacids include phosphomolybdic acid, phosphotungstic acid, phosphovanadic acid, silicomolybdic acid, silicotungstic acid, silicovanadic acid and mixtures thereof. The preferred polyacid is a phosphomolybdic acid. The terms "heteropolyacids" and "isopolyacids" are used herein in accordance with the definitions given in Advanced Inorganic Chemistry. 4th Edition, by S.A. Cotton and Geoffrey Wilkinson, Interscience Publishers, New York, pages 852-861. The following examples are presented to illustrate the invention and should not be construed as limiting the invention. EXAMPLE 1 Preparation of Catalyst Concentrate with Elemental S/Mo Atom Ratio of 5.2/1: Colloidal Sulfur Preblended with Cold Lake Crude, vehicle for preparation. Step A - Dispersion of Sulfur in Cold Lake Crude A 500-ml stainless steel beaker was charged with 99.23 g of Cold Lake Crude oil that contained 50 wt% components boiling above 520 +o C, 12.9 wt% Conradson Carbon and which exhibited an initial boiling point of 471°F. The beaker was then heated to 80-90°C and 0.77 g of colloidal sulfur (a sublimed, pharmaceutical grade product supplied by Battelle-Renwick Company, lot 2195) was stirred into the oil and the mixture was held _at 80-90°C for a period of 15 minutes. Step B - Introduction of Aqueous Phosphomolybdic Acid To a 300-cc stirred Autoclave Engineer's Autoclave was added 90.0 g of the dispersion of sulfur in Cold Lake Crude that was prepared in Step A. After flushing with nitrogen the autoclave was heated to 80°C and, with stirring, there was injected 9.99 g of an aqueous solution of phospho¬ molybdic acid that contained 4.0 wt% Mo and stirring was continued for 10 minutes at 80°C. The sulfur/molybdenum atom ratio in the mixture was 5.2/1. Phosphomolybdic acid solution was prepared by dissolving 1.60 g crystalline acid (50 wt% Mo, Fisher Scientific) in 18.4 g of deionized water at room temperature. Step C - Removal of Water Upon completion of the 10-minute stirred period at 80°C, the autoclave was heated to 150°C and held at this temperature with stirring and with nitrogen flow-through at atmospheric pressure to remove water. Step D - Formation of Catalyst Concentrate The dry catalyst precursor concentrate obtained in Step C, was converted to catalyst concentrate by increasing the autoclave temperature to 385°C and maintaining this temperature for a stirred contact period of 30 minutes. After venting autoclave pressure (some light hydrocarbon removed) and cooling to room temperature, there was obtained 78 g of catalyst concentrate that contained 0.51 wt Mo. This concentrate was assayed to determine formation of a solid molybdenum-containing catalyst by the following procedure: a sample of 30 g of this concentrate was diluted with 150 g of toluene and filtered over a Number 2 Whatman paper. Recovered solids, after toluene washing and drying under vacuum at 100°C, amounted to 1.04 g (3.47 wt% catalyst solids in catalyst concentrate). The Mo content of the recovered solids was 14.7 wt%. EXAMPLE 2 Preparation of Catalyst Concentrate with Elemental S/Mo Atom Ratio of 2.6/1: Colloidal Sulfur Preblended with Cold Lake Crude. The procedures of Example 1 were repeated except that the blend used in Step A comprised 99.61 g Cold Lake Crude and 0.39 g colloidal sulfur, an amount of sulfur that provided a S/Mo atomic ratio of 2.6/1 in Step B. There was obtained 76 g of catalyst concentrate that contained 0.53 wt% Mo and 2.9 wt% toluene-insoluble catalyst solids. The Mo content of the solids was 18.5 wt%. EXAMPLE 3 Preparation of Catalyst Concentrate with Elemental S/Mo Atom Ratio of 7.6/1: Colloidal Sulfur Preblended with Cold Lake Crude. The procedures of Example 1 were repeated except that the blend used in Step A comprised 98.85 g Cold Lake Crude and 1.15 g colloidal sulfur, an amount of sulfur that provided a S/Mo atomic ratio of 7.6/1 in Step B. There was obtained 74 g of catalyst concentrate that contained 0.54 wt% Mo and 3.1 wt% toluene-insoluble catalyst solids. The Mo content of the solids was 17.4 wt%. EXAMPLE 4 Preparation of Catalyst Concentrate with Elemental S/Mo Atom Ratio of 9.5/1: Colloidal Sulfur Preblended with Cold Lake Crude. The procedures of Example 1 were repeated except that the blend used in Step A comprised 98.6 g Cold Lake Crude and 1.40 g colloidal sulfur, an amount of sulfur that provided a S/Mo atomic ratio of 9.5/1 in Step B. There was obtained 80.0 g of catalyst concentrate that contained 0.50 wt Mo and 3.2 wt catalyst solids. The Mo content of the solids was 15.6 wt%. EXAMPLE 5 Preparation of Catalyst Concentrate Without Addition of Elemental Sulfur. The procedures of Example 1 were repeated except that colloidal sulfur was not added to Cold Lake Crude in Step A. There was obtained 82 g of catalyst concentrate that contained 0.49 wt Mo and 2.7 wt% catalyst solids. The Mo content of the solids was 18.1 wt . COMPARATIVE EXAMPLE I Preparation of Catalyst Concentrate Using Hydrogen Sulfide. Comparative Catalyst Prepared According to Methods Described in U.S. Patent No. 4,740,489. A solution of phosphomolybdic acid was prepared by dissolving 2 g of crystalline phosphomolybdic acid in 18 g of de-ionized water. This solution was mixed with 0.68 g of colloidal sulfur with stirring. Next, 9 g of this solution, which contained 4 wt% Mo, was injected into a 300-cc stirred Autoclave Engineer's Autoclave. The autoclave was heated to 80°C while stirring and was held at that temperature, with stirring, for 10 minutes. The S/Mo atomic ratio of the blend was 4.5/1. Upon completion of the 10-minute stirred period at 80°C, the autoclave was heated to 150°C and held at this temperature, with stirring and with nitrogen flow-through at atmospheric pressure to remove water. The autoclave was then pressured to 100 psig with H 2 S and was held, with stirring, at 150°C for 30 minutes. At this point, the autoclave was vented, flushed with nitrogen, sealed and heated to 365°C. There was obtained 88 g of catalyst concentrate that contained 0.52 wt% Mo and 4 wt% of catalyst solids. The Mo content of the solids was 11.8 wt%. EXAMPLE 6 Test of Catalyst of Example 1 for Hydroconversion Activity. A hydroconversion experiment was carried out with a Cold Lake Crude vacuum bottoms feedstock that contained 23.76 wt% Conradson Carbon and 94.80 wt% of components boiling above 520°C. To a 300-cc stirred autoclave from Autoclave Engineers was charged 109.5 g of vacuum Cold Lake bottoms, 5.59 g of Cold Lake Crude (12.9 wt% Conradson Carbon and 50 wt% components boiling above 520°C) and 4.91 g of the catalyst concentrate of Example 1. This amount of catalyst concentrate was sufficient to provide a Mo concentration of 208 wppm on the total reactor charge, i.e. the combined weight of vacuum bottoms, Cold Lake Crude and catalyst concentrate. The autoclave was subsequently flushed with hydrogen, sealed and stirred for 10 minutes at 90°C to mix the components. Upon cooling to room temperature, the autoclave was charged to 1350 psig with hydrogen and, with stirring, the autoclave was heated to 385°C and held at that temperature for a period of 20 minutes. At this point, pressure in the autoclave was adjusted to 2100 psig, a flow of hydrogen was started through the autoclave to maintain a rate of 0.36 liter/min (measured at the outlet at atmospheric pressure and ambient temperature after caustic scrubbing to remove H 2 S), and the temperature was increased to 445°C to cany out the hydroconversion run. Flow-through gas was collected and analyzed by mass spectrometry. After 180 minutes of stirred contact at 445°C at 2100 psig with 0.36-liter/min hydrogen flow, the flow was stopped and the autoclave was quickly cooled to 120°C. The volume of gaseous material was vented from the reactor at 120°C and was measured by wet test meter at atmospheric pressure and room temperature after first scrubbing " with caustic solution to remove H 2 S. Gas composition was determined by mass spectrometry. Liquid and solid products in the autoclave reactor, still at about 90°C, were filtered over a Number 2 Whatman filter paper to determine the yield of hot, oil insoluble solids (composite of catalyst, demetallization products and carbonaceous material). Filtered oil, after removal of 6.0 g for analytical tests, was set aside for determination of toluene-insoluble solids content. Liquid and solids remaining in the reactor after pouring out the hot oil contents were washed out with hot toluene and this wash was filtered by passing over the paper + solids from the hot oil filtration step. Filtered toluene wash liquid was then added to the oil from hot filtration and additional toluene was added so that the total weight of toluene was about 360 g. After standing for one hour at room temperature, this toluene-diluted sample was filtered over fresh Number 2 Whatman filter paper to recover toluene- insoluble solids (carbonaceous material). Toluene filtrate, combined with toluene used to wash the hot-oil-insoluble solids and toluene-insoluble solids, was distilled to recover the 520 +o C bottoms product. Hot-oil-insoluble solids and toluene-insoluble solids were dried separately under oil-pumped vacuum for one hour at 100°C prior to weighing. In this manner, there were recovered 1.00 g of hot-oil-insoluble solids, 0.91 g of toluene-insoluble solids and 9.8 g of 520 +o C bottoms, which bottoms contained 68.95 wt% Conradson Carbon components. Overall, the yield of solids (hot-oil-insoluble plus toluene-insoluble) amounted to 1.80 wt% based on the weight of 520 +o C feed and conversion of 520 +o C to 520 " °C products was 88.9%. To compare the effectiveness of this catalyst concentrate with those prepared at different S/Mo atom ratios, see Table I in Example 10 and Figure 2. EXAMPLE 7 Test of Catalyst of Example 2 for Hydroconversion Activity. The catalyst concentrate of Example 2 was tested according to the procedure given in Example 6. The reactor charge consisted of 109.5 g of vacuum Cold Lake Bottoms, 5.75 g of Cold Lake Crude and 4.75 g of the catalyst concentrate of Example 2. This amount of catalyst provided a Mo concentration of 208 wppm on the total reactor charge of feed and catalyst. There were recovered 1.24 g of hot-oil-insoluble solids, 0.90 g of toluene-insoluble solids and 11.2 g of unconverted 520 +o C bottoms. Overall, the total yield of solids amounted to 2.00 wt% on 520 +o C feed and conversion of 520 +o C bottoms to 520^C products was 87.5%. To compare effectiveness of this catalyst concentrate with those prepared at different S/Mo atom ratios, see Table I and Figure 2. EXAMPLE 8 Test of Catalyst of Example 3 for Hydroconversion Activity. The catalyst concentrate of Example 3 was tested according to the procedure given in Example 6. The reactor charge consisted of 109.5 g of Cold Lake vacuum bottoms, 5.87 g of Cold Lake Crude and 4.63 g of the catalyst concentrate of Example 3. This amount of concentrate was sufficient to provide a Mo concentration of 208 wppm on total feed. There were recovered 1.42 g of hot-oil-insoluble solids, 1.03 g of toluene-insoluble solids and 12.1 g of unconverted 520 +o C bottoms. Overall, the total yield of solids was 2.3 wt% on 520 +o C feed and conversion of 520 +o C bottoms to 520 " °C products was 86.43%. To compare the effectiveness of this catalyst with those prepared at different S/Mo atom ratios, see Table I in Example 10 and Figure 2. EXAMPLE 9 Test of Catalyst of Example 4 for Hydroconversion Activity. The catalyst concentrate of Example 4 was tested according to the procedure given in Example 6. The reactor charge consisted of 109.5 g of Cold lake vacuum bottoms, 5.50 g of Cold Lake Crude and 5.00 g of the catalyst concentrate of Example 4. This amount of concentrate provided 208 wppm Mo on total feed. There were recovered 1.41 g of hot-oil-insoluble solids, 1.69 g of toluene-insoluble solids and 11.2 g of unconverted 520 +o C bottoms. Overall, the total solids yield was 2.9 wt% on 520 +o C feed and the conversion of 520 +o C feed to 520 " °C products was 86.4%. To compare effectiveness of this catalyst concentrate with those prepared at different S/Mo atom ratios see Table I in Example 10 and the curve in Figure 2. EXAMPLE 10 Test of Catalyst of Example 5 for Hydroconversion Activity. The catalyst concentrate' of Example 5 was tested according to the procedure given in Example 6. The reactor charge consisted of 109.5 g- of Cold lake vacuum bottoms, 5.60 g Cold Lake Crude and 4.90 g of the catalyst concentrate of Example 5. This amount of concentrate provided 208 wppm Mo on total feed. There were recovered 2.36 g of toluene-insoluble solids (oil- insoluble solids recovered as part of toluene insolubles) and 11.4 g of unconverted 520 +o C bottoms. Overall, the total yield of solids was 2.2 wt% on 520 +o C feed and conversion of 520 +o C feed to 520 * 0 products was 87.4%. With reference to Table I and to the curve shown in Figure 2, it is apparent that catalyst concentrates that have maximum effectiveness, in terms of lowest solids yield (materials that could lead to reactor fouling) and highest conversion of 520 +o C feed into 520 " °C products, are obtained at S/Mo atom ratios above about 2.6/1 and below about 7.6/1. COMPARATIVE EXAMPLE II Test of catalyst of Comparative Example I for Hydroconversion Activity. The catalyst concentrate of Comparative Example I was tested according to the procedure of Example 6. The reactor charge consisted of 109.5 g of Cold Lake vacuum bottoms, 4.63 g of Cold Lake crude and 5.87 g of the catalyst concentrate of Example 13. This amount of concentrate provided 250 wppm Mo on total reactor feed. There were recovered 1.44 g of hot-oil-insoluble solids, 0.86 g of toluene-insoluble solids and 9.52 g of unconverted 520 +o C bottoms. Overall, the total yield of solids was 2.10 wt% on 520 +o C feed and conversion of 520 +o C feed to 52θ " °C products was 89.1 wt%.

Claims: CLAIMS 1. A process for converting a heavy hydrocarbonaceous chargestock to lower boiling products which process comprises reacting said hydrocarbonaceous chargestock in the presence of hydrogen, at hydroconversion conditions which include a hydrogen partial-pressure from 50 to 5000 psig and a temperature from about 650 to 900°F, in the presence of a catalyst concentrate having been prepared by the steps comprising: (a) forming a precursor concentrate by mixing: (i) a hydrocarbonaceous oil comprising constituents boiling above about 570°C; (ii) a metal compound, said metal being selected from the group consisting of Groups IVB, VB, VIB, VIIB and VII of the Periodic Table of the Elements, in an amount to provide from about 0.2 to 2 wt% metal based on said hydrocarbonaceous oil; and (b) heating the concentrate, in the substantial absence of added hydrogen, at a temperature from about 275°C to about 425°C and a total pressure of from about 0 psig to about 500 psig, for a time sufficient to convert said catalyst precursor to a solid molybdenum-containing catalyst. wherein elemental sulfur is used as a sulfiding agent at any stage of the catalyst preparation in an amount so that the atomic ratio of elemental sulfur to metal is about 1/1 to 8/1. 2. The process of claim 1 wherein the elemental sulfur is added to the hydrocarbonaceous chargestock prior to addition of the metal compound. 3. The process of claim 1 wherein the hydrocarbonaceous oil of step (a) comprises a blend of gas oil and a vacuum residuum. 4. The process of claim 2 wherein the hydrocarbonaceous oil of step (a) is an atmospheric distillation residuum. 5. The process of claim 2 wherein the amount of phosphomolybdic acid is such that it provides from about 0.2 to 1 wt% Mo based on said hydrocarbonaceous oil. 6. The process of claim 5 wherein the amount of sulfur is such that the atomic ratio of sulphur to molybdenum is from about 2/1 to 7/1. 7. The process of claim 6 wherein the amount of phosphomolybdic acid is such that it provides about 0.2 to 1 wt% Mo, based on said hydrocarbonaceous chargestock, and wherein the elemental sulfur ~ is added as a concentrate in hydrocarbonaceous oil and is added to the precursor concentrate of step (a) prior to heating of step (b). 8. The process of claim 1 wherein the sulfur is in the form of a sublimed powder. 9. The process of claim 7 wherein the sulfur is in the form of a sublimed powder.

Inventors: ALDRIDGE CLYDE LEE, BEARDEN ROBY JR, ALDRIDGE, CLYDE, LEE, BEARDEN, ROBY, JR.
Applicants: EXXON RESEARCH ENGINEERING CO, EXXON RESEARCH AND ENGINEERING COMPANY
Application year: 1991
Main classification: C10G47
IPC codes: B01J27, B01J37, C10G47, C10G49