Titania-supported hydrotreating catalysts

Abstract

TiO.sub.2-supported catalysts include at least molybdenum or tungsten as active components for hydrotreating processes, in particular for the removal of sulfur and nitrogen compounds as well as metals out of crude oil fractions and for the hydrogenation of sulfur oxides.

Claims

1. Supported catalyst composition for hydrotreating, comprising: shaped titania support bodies having at least one oxide of molybdenum and/or tungsten on the surface thereof; and having a surface area of at least 80 m.sup.2 per gram, a pore volume measured by mercury porosimetry of at least 0.25 cm.sup.3/g, a side-crush strength greater than 7 N/mm, and a tapped bulk density in the range of 600-1200 kg/m.sup.3, wherein the titania support bodies contain 70 to 100 wt. % TiO.sub.2 and up to 30 wt. % silica.

2. Catalyst composition according to claim 1, wherein the titania support bodies contain 80 to 100 wt. % TiO.sub.2 and up to 20 wt. % silica.

3. Catalyst composition according to claim 1, having a content of molybdenum and/or tungsten in the range of 9.0 to 16.0 wt. %, expressed as trioxides, calculated on the total weight of the supported catalyst composition.

4. Catalyst composition according to claim 1, further comprising a total content of at least one of cobalt and nickel in the range of 0 to 6.5 wt. %, expressed as Co.sub.3O.sub.4 or NiO, calculated on the total weight of the supported catalyst composition.

5. Catalyst composition according to claim 1, wherein at least 20 weight percent of the supported precursor particles of the catalytically active oxides being present after calcination are smaller than 50 nm.

6. Catalyst composition for hydrotreating according to claim 1, obtainable by applying an aqueous solution of at least one salt of molybdenum and/or tungsten on shaped titania support bodies followed by drying and calcining the obtained bodies.

7. Process for the preparation of a catalyst composition as claimed in claim 1 wherein a solution of at least one salt of molybdenum and/or tungsten is applied on titania support bodies in the presence of a protic solvent and optionally an alkali compound, the formed catalyst bodies are recovered following precipitation, drying and calcining the obtained bodies.

8. Process for reclaiming the metal selected from cobalt and molybdenum from the catalyst composition according to claim 1 after use thereof, said process comprising the steps of: calcining the catalyst composition in air at a temperature in the range of 400-700° C.; and subsequent treating the calcined catalyst composition with an aqueous solution of ammonia and ammonium carbonate.

9. Process according to claim 8, further comprising the step of evaporating the ammonia and recovering the formed cobalt carbonate.

10. Process according to claim 9, further comprising, after separation of cobalt carbonate, the step of evaporating water to obtain the molybdenum metal as molybdate.

11. A process for the hydrogenation of sulfur dioxide, comprising subjecting a reaction gas containing sulfur dioxide to a hydrogenation step with a catalyst composition according to claim 1, thereby hydrogenating the sulfur dioxide to hydrogen sulfide.

12. Process according to claim 11, wherein the hydrogenation step is carried out at a temperature from less than 250° C.

13. A process for removal of sulfur and nitrogen compounds from crude oil fractions comprising treating crude oil fractions with hydrogen and a catalyst composition according to claim 1, thereby removing the sulfur and nitrogen compounds.

14. A process for removal of metals out of crude oil fractions comprising treating crude oil fractions with hydrogen and a catalyst composition according to claim 1, thereby removing the metals.

15. The catalyst composition according to claim 1, wherein said titania support bodies contain no alumina.

16. The catalyst composition according to claim 1, wherein the titania support bodies comprise silica.

17. The catalyst composition according to claim 4, further comprising 2-6.5 wt. % of at least one of Co.sub.3O.sub.4 or NiO, based the total weight of the catalyst composition.

18. Catalyst composition according to claim 1, further comprising platinum, palladium, rhodium, rhenium, silver, gold, or mixtures thereof.

19. A catalyst composition for hydrotreating, comprising: a preformed, shaped support comprising 70-100 wt. % TiO.sub.2, wherein said support contains no alumina, said support loaded with: 9-16 wt. % of MoO.sub.3; and 2-6.5 wt. % of Co.sub.3O.sub.4.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) This invention relates to the hydroprocessing catalyst and hydroprocessing of chemical and petroleum feedstocks using said catalyst composition containing Mo and/or W and optionally Ni and/or Co and an inert refractory oxide, of which 80 wt % or more is titania and the remainder being silicon dioxide.

(2) In more detail, the present invention provides a supported catalyst composition for hydrotreating in the form of shaped titania support bodies having at least one oxide of molybdenum and/or tungsten on the surface thereof and having a surface area of at least 80 m.sup.2 per gram, a pore volume measured by mercury porosimetry of at least 0.25 cm.sup.3/g, a side-crush strength greater than 7 N/mm, and a tapped bulk density in the range of 600-1200 kg/m.sup.3.

(3) The freshly calcined catalyst has generally a surface area of at least 80 m.sup.2 per gram, preferably of at least 125 m.sup.2 per gram, and even more preferably of at least 135 m.sup.2 per gram and most preferably of at least 150 m.sup.2 per gram, a pore volume measured by mercury porosimetry of at least 0.25 cm.sup.3/g, preferably of at least 0.30 cm.sup.3/g, and more preferably of 0.34 cm.sup.3/g, a side crushing strength of at least 7 N/mm, preferably at least 8 N/mm, and more preferably at least 10 N/mm, and a tapped bulk density in the range of 600-1200 kg/m.sup.3, more preferably 800-1200 kg/m.sup.3.

(4) As known in the state of art, for example in “Catalyst Handbook” (2nd Edition) by Martyn V. Twigg, (1989) or “Fundamentals of Industrial Catalytical Processes” by Robert J. Farrauto and Calvin H. Bartholomew (1997), the properties of the catalyst in respect of side crush strength and bulk density are important parameters for their usefulness as catalyst in the reactors. The side crush strength is defined as the resistance of formed catalysts to compressive forces. Measurements of the side crush strength are intended to provide an indication of the ability of the catalyst to maintain its physical integrity during handling and use. A standard test method for radial crush strength of extruded catalyst and catalyst carrier particles is described in ASTM D6175-03(2008) which is also applied here as detailed below.

(5) The measurement of tapped density has been formalized in a number of standard methods such as for catalysts in ASTM 4164 as a “Standard Test Method for Mechanically Tapped Packing Density of Formed Catalyst and Catalyst Carriers” which is applied here as detailed below.

(6) The inventive supported catalyst composition for hydrotreating is obtainable by applying an aqueous solution of at least one salt of molybdenum and/or tungsten on titania support bodies and calcining the obtained bodies.

(7) The term hydroprocessing is used herein to cover a range of hydrotreatment processes where the hydrocarbon feed is brought in contact with hydrogen in order to modify key physical and chemical properties.

(8) For applying the aqueous solution of at least one salt of molybdenum and/or tungsten on titania support, solutions of molybdenum and/or tungsten in the form of their water-soluble salts are generally used; aqueous solution of molybdates and/or tungstates or metal-phosphorous complexes (e.g. heteropolyacids) are preferred.

(9) During the application step, the hydrated forms of the metal components are deposited onto the titania support. In more detail, suitable precursors such as metals salts are dissolved in water in the concentrations to result in the desired metals loading upon (dry) impregnation, drying and calcination. Good examples are basic cobalt or nickel carbonate, ammonium molybdate or tungstate salts. These are converted into e.g. heteropolyacid structures. This can be achieved by heating the dissolved compounds in water, optionally in the presence of a complexing agent such as phosphoric acid. First, mechanically shaped titania supports can be loaded in a suitable vessel, such as a blender, e.g. a cone blender. The pore volume impregnation was effected with an impregnation solution at the rate of 0.01-0.1 ml/min/g support. The amount might be varied depending on the intended load of the supports. After dosing of the impregnation solution, the impregnated formed bodies are aged, preferably for at least 12 hrs, more preferred for at least 24 hours. The resulting material is then subjected to drying and calcining steps. Before drying, an aging step of the freshly impregnated material is preferably carried out for a time of up to 36 hours, preferably between 12 and 24 hours in order to serve for a more homogeneous distribution of the metal components deposited in the pores of the material. The drying step is carried out at a temperature in the range of 100° to 150° C. for a time up to several hours in order to remove the solvent. Thereafter, calcination is typically carried out for a time between 30 and 240 minutes at a temperature in the range of 300° to 600° C. The active catalyst is obtained after a sulfidation step in which metal oxides are converted to their corresponding sulfides. The sulfidation can be done in an ex-situ presulfiding step or in-situ after loading of the catalyst in the hydrotreatment reactor with sulfur compounds and processes known to those skilled in the art.

(10) By the term ‘supported’ or ‘support’ it is to be understood that the composition has a preformed, shaped catalyst support which is then loaded with metal compounds via impregnation or deposition. Generally, in this supported catalyst composition, the support is a separate distinct material within the composition, i.e. the support is generally not prepared, in a shaping process, from powderous material already loaded with metal compounds. Said shaping can be effected mechanically, for example, by extrusion of a paste-like material. The shaped bodies have generally a diametral size of a few millimeters in a range starting from 1 up to 10 mm. The shape of the bodies can be cylindrical, trilobal, tetralobal as long as the mechanical properties are maintained.

(11) In one embodiment, the inventive titania support can contain 70 to 100 wt. %, preferably 80 to 100 wt. % TiO.sub.2 and up to 30 wt. %, preferably 20 wt. % silica, which can raise the thermal stability of the titania.

(12) One embodiment of the inventive catalyst composition has a content of molybdenum and/or tungsten in the range of 9.0 to 25.0 wt. %, preferably 10 to 16 wt. %, more preferrably 12 to 16 wt %, calculated as trioxides, on the total weight of the calcined catalyst.

(13) Another embodiment of the inventive catalyst composition can, in addition to the content of molybdenum and/or tungsten, have a content of at least one of cobalt and nickel in the range of up to 10 wt. %, preferably 6.5 wt. %, more preferably 2 to 4 wt. %, expressed as Co.sub.3O.sub.4 or NiO and calculated on the total weight of the supported catalyst composition. Suitable nickel compounds, based on a similar criteria as for molybdenum, are nickel carbonate, nickel oxide, nickel hydroxide, nickel phosphate, nickel formiate, nickel sulfide, nickel molybdate, or a mixture of two or more thereof. Additionally soluble salts such as nickel nitrate, sulphate or acetate may be used in combination with one or more of these compounds and/or with each other. The corresponding cobalt compounds are also suitable.

(14) Preferably, the inventive catalyst composition contains a combination of molybdenum and cobalt in the aforementioned content ranges for each metal.

(15) Though the present invention is directed to supports being loaded with the afore mentioned metal compounds, the invention is also concerned with a supported catalyst composition for catalytic processes like hydrogenation and oxidation reactions in the form of shaped titania support bodies having at least one catalytically active material, selected from platinium, palladium, rhodium renium silver and gold or mixtures in an amount of up to 8% wt, preferably 5% wt, calculated on the total weight of the calcined catalyst, loaded on the surface thereof and having a surface area of at least 80 m.sup.2 per gram, a pore volume measured by mercury porosimetry of at least 0.25 cm.sup.3/g, a side-crush strength greater than 7 N/mm, and a tapped bulk density in the range of 600-1200 kg/m.sup.3.

(16) The active components have been applied finely divided on the titania support, which leads to the precursor (oxides) of the active species being advantageously smaller than 50 nm and preferably smaller than 20 nm. Preferably scanning transmission electron microscopy with elemental analysis is used to assess the size of the active components. It has been surprisingly found that the catalysts according to the invention are very well appropriate to hydrogenate sulfur dioxide to hydrogen sulfide, in particular in the hydrogenation step required in the so-called SCOT process to treat Claus tail gases.

(17) The multi-step Claus process recovers sulphur from the gaseous hydrogen sulphide present in raw natural gas and from the by-product gases containing hydrogen sulphide derived from refining crude oil and other industrial processes. The by-product gases mainly originate from physical and chemical gas treatment units (Selexol, Rectisol, Purisol and amine scrubbers) in refineries, natural gas processing plants and gasification or synthesis gas plants. These by-product gases may also contain hydrogen cyanide, hydrocarbons, sulphur dioxide or ammonia. Gases with an H.sub.2S content of over 25% are suitable for the recovery of sulphur in straight-through Claus plants. The tail gas from the Claus process is still containing combustible components and sulphur compounds (H.sub.2S, H.sub.2 and CO) is either burned in an incineration unit or further desulphurized in a downstream tail gas treatment unit.

(18) In such SCOT (Shell Claus Off-Gas Treating) process, the gas flow out of the last catalytic Claus reactor is cooled to condense the elementary sulphur, after which the gas flow has to be reheated to establish the temperature required to hydrogenate the remaining sulphur dioxide to hydrogen sulphide. The hydrogen sulphide can be selectively removed by absorption into liquids containing alkanolamines. Remaining sulphur dioxide reacts irreversibly with the alkanolamines, in contrast to hydrogen sulphide, which can be thermally desorbed. Therefore, sulphur dioxide has to be removed completely.

(19) It is commercially very attractive to perform the reheating of the gas flow out of the sulfur condensor with steam, and surprisingly, the catalyst according to this invention has a high activity in a temperature range from 200° C. to 240° C. It was particularly surprising that, even at lower temperatures such as 200° C., a complete conversion of sulfur dioxide can be achieved. Since the temperature that can be established with steam is about 240° C., the inventive catalyst is of particular advantage in the SCOT process in view of its sufficiently high activity already at 200° C. to 240° C., in particular between 215° C. and 240° C.

(20) The final sulfur recovery of the SCOT process and the like is mainly determined by the amount of mercaptanes formed during the hydrogenation of sulfur dioxide and the effectiveness of the simultanous removal of COS and CS.sub.2 by hydrolysis, with the water contained in the process gas. It has been observed that the amount of mercaptanes generated employing the inventive titania-supported catalyst is substantially lower than the amount produced by an alumina-supported catalyst.

(21) Very high hydrolysis efficiencies can be obtained with the catalysts according to the present invention, compared to alumina supported products and low pore volume titania based catalysts.

(22) Also for the removal of metals out of crude oil fractions titania-supported catalysts according to the present invention are very attractive. Due to the high pore volume and macro/meso-porous properties of the support and inventive catalysts, much metal can be loaded on the catalyst bodies before plugging of the pores brings about a drop in activity. Moreover, due to the highly dispersed state of the active surface components, it is stated that these catalysts pick up much enhanced quantities of metallic foulants.

(23) For the inventive catalysts, a further advantage has been surprisingly found, i.e. that the spent titania-supported catalysts can be treated for recovery of the metals in a very attractive way. It has been found by the inventors that, after combustion of the carbon deposited into and onto the catalyst bodies during the hydrotreating step, the metals, i.e. molybdenum, tungsten, cobalt, nickel as well as vanadium deposited on the catalysts from the crude oil fraction can be readily dissolved in a mixture of concentrated ammonia and ammonium carbonate. To raise the rate of the dissolution, the reaction can be performed at elevated pressures. The titania support does not dissolve in alkaline solutions, whereas molybdenum, tungsten and vanadium enters the solution as molybdates, tungstates or vanadates, and cobalt and nickel dissolve as ammonia complexes.

(24) After separation from the titania support the cobalt and nickel can be separated by thermal desorption of the ammonia, which leads to precipitation of the corresponding carbonates. The other metal(s) present as oxyanions remain in the solution and can be recovered in further process steps.

(25) Therefore, the invention also concerns a process for reclaiming the metals, particularly cobalt and/or molybdenum, from the inventive catalyst composition after use thereof, said process comprising the steps of calcining the catalyst composition in air at a temperature in the range of 400-700° C. and subsequent treating the calcined catalyst composition with solvent for the metal compounds, for cobalt and molybdenum an aqueous solution of ammonia and ammonium carbonate, and recovering the solved metals from the solution.

(26) For cobalt and molybdenum, the further treatment envisages a step of evaporating the ammonia and recovering the formed cobalt carbonate, and after separation of cobalt carbonate, the step of evaporating water to obtain the molybdenum metal as molybdate which might any ammonium molybdate.

(27) The invention will further be illustrated by way of the following examples for preparing and testing the inventive catalysts.

EXAMPLES

Example 1

(28) For preparing the inventive supported catalyst composition, a TiO.sub.2-material commercially available form Euro Support Manufacturing in the form of trilobes was used and impregnated with solutions of the metal salts. Generally, two types (A, B) of impregnation solutions were used exemplarily here, but other solutions with different ratios of the metals might be used to obtain differing loads on the support as long as the ratios lead to the loads as defined in the claims. The impregnation solutions used in the following examples were based on: A) Complex molybdates dissolved as polyoxy-anions and Cobalt nitrate B) Molybdenum and Phosphorous based heteropolyacids and Cobalt nitrate
Solution Preparation:
Preparation of Solution A:

(29) 27.86 gram of (NH.sub.4).sub.2Mo.sub.2O.sub.7 was added under stirring to 52.4 ml of demineralised water at a temperature of 60° C. After 5 minutes of stirring at the temperature, 3.81 gram of MoO.sub.3 was added. When the MoO.sub.3 was dissolved the solution was cooled to 30° C. A solution of 37.6 gram of Co(NO.sub.3).sub.2 (Co content 13.4%) was added. The final pH of the resulting solution was 4.7. The total volume of the solution was 100 ml.

(30) Preparation of Solution B:

(31) 42.66 gram of MoO.sub.3 was added under stirring to 85.9 ml of water at 65° C. After 20 minutes 3.27 gram of H.sub.3PO.sub.4 (concentration 85 wt. %) was added. Subsequently 14.27 gram of Cobalt carbonate (Co content 45.3%) was added stepwise. After the addition of the total amount of Cobalt carbonate was finished 1.19 gram HNO.sub.3 (concentration 65%) was added. The solution was cooled to room temperature. The final pH of resulting solution was 4.1. The total volume of the solution was 100 ml.

(32) Impregnation Procedure:

(33) 100 grams of the titania supports indicated as S-1 or S-2 (Table 1), which are commercially available form Euro Support under the trade names Mirkat 200, 300 and 400, were loaded in a cone blender. The pore volume impregnation was effected with solution A or B by addition of 42 ml of the impregnation solution at the rate of 0.5 ml/min here. The amount might be varied depending on the intended load of the supports. After dosing of the impregnation solution, the impregnated formed bodies were aged for 24 hours. Next the catalyst was dried at 120° C. (overnight) and calcined at 400° C. (1 hour).

(34) The characterizations of the supports S-1 and S-2 and of the impregnated catalysts are detailed in the following Tables 1 and 2. The abbreviations used in the tables have the following meaning: BET-SA: Total specific surface area, determined by nitrogen adsorption, according to the theory developed by Brunauer, Emmet and Teller. PV.sub.Hg: Pore volume as determined by mercury intrusion up to a pressure of 2000 bar TBD: Tapped bulk density as measured according to ASTM (American Society for Testing And Materials) method D 4164-03. CS: Side crush strength (N/mm). The force that is applied to break an extruded body in radial direction. The method applied deviates from the ASTM method D 6175-03 in that, in the method here, a 2 mm anvil and a flat plate have been used instead of two flat plates.

(35) TABLE-US-00001 TABLE 1 BET SA PV.sub.Hg TBD CS Support Shape/size (m.sup.2/g) (ml/g) (kg/m.sup.3) (N/mm) S-1 1.8 mm trilobes 266 0.43 690 10 S-2 1.8 mm trilobes 229 0.44 706 15

(36) The two supports S-1 and S-2 have been treated by applying solution B to it, and the following characteristics for the obtained inventive catalysts C-1 and C-2 have been observed as shown in Table 2.

(37) TABLE-US-00002 TABLE 2 BET SA PV.sub.Hg Co.sub.3O.sub.4 MoO.sub.3 TBD CS Catalyst Support (m.sup.2/g) (ml/g) (wt %) (wt %) (kg/m.sup.3) (N/mm) C-1 S-1 180 0.34 3 15.1 900 11 C-2 S-2 159 0.37 3.1 14.6 979 17

Example 2

(38) In a comparative example, the above two titania-based catalysts C-1 and C-2 according to the invention have been used in testing of HDS/HDN using respectively LGO as feed stock, with low sulfur and nitrogen content, and a mix of heavier feed stocks with a high sulfur and nitrogen content. The characterizations of the impregnated catalysts and of alumina-supported reference catalysts RC-1 and RC-2 (characteristics summarised in Table 3).

(39) TABLE-US-00003 TABLE 3 BET SA PV.sub.Hg Co.sub.3O.sub.4 MoO.sub.3 TBD CS Catalyst Support Size (m.sup.2/g) (ml/g) (wt %) (wt %) (kg/m.sup.3) (N/mm) C-1 S-1 1.8 mm trilobes 180 0.34 3 15.1 900 11 RC-1 alumina 1.1 mm trilobes 190 0.56 6.2 22.6 742 C-2 S-2 1.8 mm trilobes 159 0.37 3.1 14.6 979 17 RC-2 alumina 1.3 mm 127 0.31 4.5 26.5 915 21 extrusion

(40) The following Table 4 shows the available BET surface area per unit volume in the test reactor.

(41) TABLE-US-00004 TABLE 4 BET SA Test reactor loading BET surface area per loaded Catalyst (m.sup.2/g) density (kg/m3) volume in test reactor (m.sup.2/l) C-1 180 900 162000 RC-1 190 742 140980 C-2 159 979 155661 RC-2 127 915 116205
Testing Procedure:

(42) In the following experiments, an isothermal reactor (30 mm inner diameter) was loaded with 100 ml catalyst. The catalysts were pre-sulfided using DMDS(dimethyl disulfide). The pre-sulfiding procedure is well known to those skilled in the art.

Example 3

(43) In another comparative example, after presulfiding catalyst C-1 and its reference RC-1 were tested using a feed as specified in Table 5.

(44) TABLE-US-00005 TABLE 5 Density@ 15° C. [kg/m.sup.3] 848.3 Refractive index @ 20° C. 1.4716 Sulfur content [mg/kg] 7990 Nitrogen content [mg/kg] 112.7 Color ASTM D 1500 0.3 Bromine index [mg Br/100 g] 2958 Composition by liquid chromatography (HPLC) Saturated [% m/m.] 68.4 Monoaromatics [% m/m.] 20.2 Diaromatics [% m/m.] 11.2 Triaromatics [% m/m.] 0.2

(45) The test conditions were as follows: Pressure (H.sub.2):3 MPa; WHSV: 1.0 kg.sub.feed/l.sub.cat/h; H.sub.2/feed: 350 l.sub.n/kg.sub.feed (average); Temperature: 350, 360, 370° C.

(46) The HDS and HDN activity of the catalysts was as summarised in Table 6.

(47) TABLE-US-00006 TABLE 6 C-1 RC-1 C-1 RC-1 Temperature (° C.) ppm S ppm S ppm N ppm N feed 8000 8000 112 112 350 34 30.7 5.1 16.6 360 17.3 12.5 3.4 12.6 370 8.4 7.65 2.9 8.0 Temperature (° C.) at 10 ppm 367 362 340 370

Example 4

(48) In yet another comparative example, after presulfiding catalyst C-2 and its reference (RC-2) were tested using a feed as specified in Table 7.

(49) TABLE-US-00007 TABLE 7 Density @15° C. [kg/m.sup.3] 939.2 Density@50° C. [kg/m.sup.3] 915.8 Refraction index n.sub.D50° C. 1.5110 Colour ASTM D 1500 >8 Freezing point [° C.] +39 Sulphur content [% hm.] 2.28 Nitrogen content [ppm] 2258 Carbon precursors (MCRT) [% hm.] 1.34 Metal content: V [mg/kg] 1.90 Ni [mg/kg] 0.62 Fe [mg/kg] 1.78 GC separation Sawatzky: saturated [% hm.] 31.0 mono-aromatic [% hm.] 22.0 di-aromatic [% hm.] 13.2 tri-aromatic [% hm.] 13.3 poly-aromatic [% hm.] 18.8 polar compound [% hm.] 1.7

(50) The test conditions were as follows: Pressure (H.sub.2): 6 MPa; WHSV: 1.0 kg/l catalyst/h; H.sub.2/Feed-330 m.sup.3/m.sup.3; Temperature program: 370-390-405-420° C.

(51) The HDS and HDN activities of the catalysts have been summarised in Table 8.

(52) TABLE-US-00008 TABLE 8 C-2 RC-2 C-2 RC-2 Temp. Celsius ppm S ppm S ppm N ppm N Feed 22800 22800 2258 2258 370 2972 3445 1250 1250 390 966 1619 938 1050 405 534 1047 809 960 420 412 686 826 1042

Example 5

(53) A series of catalysts has been prepared for testing of SO.sub.2 hydrogenation and hydrolysis reactions. The catalysts have been prepared using preparation methods A or B (Example 1) using a range of titania support materials as outlined in Tables 9 and 10.

(54) TABLE-US-00009 TABLE 9 BET SA PV.sub.Hg TBD CS Support Shape/size (m.sup.2/g) (ml/g) (kg/m.sup.3) (N/mm) S-3 1.8 mm trilobes 211 0.42 793 13 S-4 1.8 mm trilobes 162 0.48 639 8 S-5 1.5 mm extrusions 266 0.43 721 8 S-6 2.3 mm extrusions 166 0.32 885 10 S-7 1.8 mm trilobes 229 0.44 706 15

(55) TABLE-US-00010 TABLE 10 BET SA PV.sub.Hg Co.sub.3O.sub.4 MoO.sub.3 CS TBD Catalyst Support Method Shape (m.sup.2/g) (ml/g) (wt %) (wt %) (N/mm) (kg/m.sup.3) C-3 S-5 B 1.5 mm 140 0.35 3.1 15.0 9 1163 circular extrusions C-4 S-6 B 2.3 mm 155 0.26 2.2 11.2 10 1066 circular extrusions C-5 S-7 B 1.8 mm 159 0.37 3.1 14.6 17 979 trilobes C-6 S-4 B 1.8 mm 131 0.37 2.7 13.9 7 886 trilobes C-7 S-7 A 1.8 mm 190 0.40 2.4 10.6 15 898 trilobes C-8 S-3 B 1. 8 mm 156 0.39 3.2 14.3 10 982 trilobes

(56) Table 11 summarises the characteristics of commercial alumina based CoMo reference catalysts RC-3 and RC-4 for SO.sub.2 hydrogenation and CS.sub.2 and COS hydrolysis in Claus tail gas, one specifically for operating temperatures <240° C., the other for temperatures >260° C.

(57) TABLE-US-00011 TABLE 11 BET TBD SA PV.sub.Hg Co.sub.3O.sub.4 MoO.sub.3 (kg/ Catalyst Shape (m.sup.2/g) (ml/g) (wt %) (wt %) CS m.sup.3) RC-3 2.2 mm 248 0.67 3.1 13.6  38 669 for T < 240 trilobes (N/mm) ° C. RC-4. 3-5 mm 304 0.43 2.9 9.1 100 763 for T > 260 spheres (N) ° C. flat plate

(58) The following table shows the available BET surface area per unit volume in the test reactor.

(59) TABLE-US-00012 TABLE 12 BET specific Test reactor surface area loading density BET surface area per loaded Catalyst (m.sup.2/g) (kg/m3) volume in test reactor (m.sup.2/l) C-3 140 1131 158312 C-4 155 1036 160503 C-5 159 966 153642 C-6 131 829 108547 C-7 190 869 165034 C-8 156 926 144503 RC-3 248 647 160605 RC-4 304 712 216326

Example 6

(60) The previously described catalysts C-3 to C-8 according to the invention have been tested comparatively with two reference catalysts RC-3 and RC-4 at a range of temperatures. The catalysts were pre-sulfided before testing in a gas stream containing 1 mol % H.sub.2S, 4 mol % H.sub.2, N.sub.2 balance, at a space velocity (GHSV) of 650 Nm.sup.3/m.sup.3/h for 16 hours, at a temperature of 375° C. After pre-sulfiding the feed gas was switched to a gas containing 1 mol % H.sub.2S, 0.5 mol % SO.sub.2, 1.5 mol % H.sub.2, 1.1 mol % CO, 16.7 mol % CO.sub.2, 0.025 mol % COS, 0.025 mol % CS.sub.2, 22 mol % H.sub.2O, N.sub.2 balance. The space velocity was either 825 or 1500 Nm.sup.3/m.sup.3/h. The catalysts were tested at 290° C., 260° C., 230° C., 220° C., 215° C. and 200° C., for ca. 12 hours at each temperature. The catalytic activity was characterized by SO.sub.2, CS.sub.2, COS and CO conversion, as well as production of methyl mercaptan, CH.sub.3SH. The results of testing at a space velocity of 825 Nm.sup.3/m.sup.3/h are summarized in Table 13. The data refer to the conversions and mercaptan production after 12 hours testing at each temperature.

(61) TABLE-US-00013 TABLE 13 CH.sub.3SH in SO.sub.2 CS.sub.2 COS CO product gas Temper- conversion conversion conversion conversion (mol ppm ature: (%) (%) (%) (%) dry basis) 290° C. C-3 100 100 92 99 0 C-4 100 100 92 99 0 C-5 100 100 91 99 0 C-6 100 100 93 99 0 C-7 100 100 92 99 0 C-8 100 100 92 99 0 RC-3 100 100 92 99 0 RC-4 100 100 92 99 0 260° C. C-3 100 100 94 99 0 C-4 100 100 95 99 0 C-5 100 100 94 99 0 C-6 100 100 95 99 0 C-7 100 100 95 99 0 C-8 100 100 94 99 0 RC-3 100 100 94 99 0 RC-4 100 100 94 99 14 230° C. C-3 100 100 95 100 41 C-4 100 100 95 100 14 C-5 100 100 96 100 23 C-6 100 100 97 100 8 C-7 100 100 96 100 18 C-8 100 100 96 100 22 RC-3 100 100 96 100 34 RC-4 100 100 96 100 57 220° C. C-3 100 100 95 100 44 C-4 100 100 97 100 31 C-5 100 100 97 100 41 C-6 100 100 97 100 18 C-7 100 100 97 100 33 C-8 100 100 97 100 40 RC-3 100 100 96 100 63 RC-4 100 99 94 99 80 215° C. C-3 100 100 95 100 59 C-4 100 100 97 100 44 C-5 100 100 97 100 50 C-6 100 100 97 100 39 C-7 100 100 97 100 45 C-8 100 100 97 100 53 RC-3 100 100 95 100 75 RC-4 100 99 90 99 77 200° C. C-3 100 100 95 100 107 C-4 100 100 97 100 80 C-5 100 100 96 100 101 C-6 100 100 98 100 91 C-7 100 100 95 100 76 C-8 100 100 96 100 99 RC-3 100 98 90 98 109 RC-4 100 98 82 95 90

(62) The results of testing at a space velocity of 1500 Nm.sup.3/m.sup.3/h are summarized in Table 14.

(63) TABLE-US-00014 TABLE 14 CH.sub.3SH in SO.sub.2 CS.sub.2 COS CO product gas Temper- conversion conversion conversion conversion (mol ppm ature: (%) (%) (%) (%) dry basis) 290° C. C-3 100 100 92 98 0 C-6 100 100 92 99 0 C-7 100 100 92 99 0 C-8 100 100 91 99 0 RC-3 100 100 91 99 0 RC-4 100 100 93 99 0 260° C. C-3 100 100 94 99 0 C-6 100 100 95 99 0 C-7 100 100 94 99 0 C-8 100 100 94 99 0 RC-3 100 100 93 99 0 RC-4 100 100 94 99 18 230° C. C-3 100 100 90 98 36 C-6 100 100 96 100 18 C-7 100 100 94 99 32 C-8 100 100 95 99 25 RC-3 100 99 91 99 50 RC-4 100 94 88 97 34 220° C. C-3 100 100 85 97 59 C-6 100 100 93 100 35 C-7 100 100 91 99 45 C-8 100 100 89 99 43 RC-3 100 97 84 98 78 RC-4 100 81 62 85 23 215° C. C-3 100 100 76 96 77 C-6 100 100 91 100 57 C-7 100 100 88 98 57 C-8 100 100 82 98 60 RC-3 100 92 70 96 76 RC-4 100 70 57 73 16 200° C. C-3 100 98 37 88 116 C-6 100 98 55 93 115 C-7 100 93 50 89 91 C-8 100 95 20 86 112 RC-3 100 72 −8 86 56 RC-4 100 65 56 51 15

(64) As it can be seen from the above examples that the catalyst composition according to the invention is excellent in its HDS and HDN activity and can be advantageously used in processes for removal of sulfur and nitrogen compounds from crude oil fractions by treatment with hydrogen.

(65) Catalysts according to the invention are also excellently suited for hydrogenation of SO.sub.2 with complete conversion in gases like Claus off gas. At moderate temperatures, 215-230° C., the catalysts combine high hydrogenation and hydrolysis activities with a substantially lower mercaptan production, compared to alumina supported catalysts.