NL8403107A - CATALYST, AND METHOD FOR TREATING AN ASPHALT-CONTAINING HYDROCARBON WITH THIS CATALYST. - Google Patents

Description

t N.0. 32759 '*' X 'Λ i

Catalyst, as well as a method of treating an asphalt-containing hydrocarbon with this catalyst.

Background of the invention

The present invention relates to a hydrogenation catalyst, to a process for preparing such a catalyst and its use for the demetallization and desulfurization of asphalt-containing hydrocarbons. More particularly, the present invention relates to the preparation of a molybdenum-containing hydrogenation catalyst containing a controlled amount of access macropores interconnecting catalytically active micropores, and the use of the catalyst in the demetallization and desulfurization of asphalt-containing hydrocarbons .

Description of the Prior Art It is known in the art to remove metals and sulfur from petroleum asphalt containing hydrocarbon fractions by subjecting them to treatment with hydrogen at elevated temperatures and pressures while in contact with a catalyst containing hydrotreating components. .

Usually, Group VI and Group VIII metals or their oxides and sulfides have been used as the metallic components of the catalyst. For example, a catalyst that has been used commercially in the hydrodesulfurization of a batch of asphalt-containing crude oil is a nickel-cobalt molybdenum on alumina catalyst. Such a catalyst and such a hydrodesulfurization process is described, for example, in Re 29,315. The life of conventional hydrodesulfurization catalysts, as described above, is shortened proportionally to the concentration of metals found in the heavy oils. These metals are adsorbed on the catalyst, blocking the pores and deactivating the hydrodesulfurization catalyst.

Hydrogenation catalysts, previously used as demetalization catalysts, such as described in U.S. Patent 4,411,824, provide good demetallization, but the accompanying desulfurization is usually poor, requiring excessive initial temperatures to achieve suitable desulfurization , for example 400eC or higher.

The understanding that large catalyst pores may be useful in S403107 * 2 simultaneous demetallation and desulfurization of heavy oils is described in U.S. Pat. No. 3,898,155. This reference describes the simultaneous demetallization and desulfurization of heavy oils containing at least 50 ppm of metals, using a catalyst composition comprising a Group VI-B metal and at least one Group VIII metal composed with alumina which catalyst composition has an average pore diameter greater than 10 nm units, with 10-40% of the total pore volume in pores with a diameter greater than 60 nm, 60-90% of the total 10 pore volume in pores with a diameter is in the range of 0-60 nm and at least 80% of the micropore volume is in pores with a diameter of at least 10 nm.

A process for the hydrodemetallization and hydrodesulfurization of asphalt-containing hydrocarbons using a bimodal catalyst is also described in U.S. Patent 4,225,421. This reference describes the catalyst as a Group VIB metal supported on an aluminum oxide-containing support, with about 60% to about 95% of its micropore volume being in micropores with diameters in the range of about 5 nm to about 20 nm. nm, 0% to about 15% of its micropore volume in micropores is in diameters within the range of about 20 nm to * 60 nm and about 3% to about 30% of the total pore volume is in macropores with diameters of 60 nm- or more.

Summary of the invention

According to the invention, an optimal demetallization and desulfurization of asphalt-containing hydrocarbons is obtained under hydrogenation conditions, using a catalyst containing molybdenum and at least one Group VIII metal composed with alumina, which catalyst has a total pore volume, based on mercury penetration measurement of at least 0.4 cmVg, a macropore volume in the range of 0.02 to 0.2 cnP / cm 2 catalyst volurae and a micropore volume of at least 0.12 cm 2 / cm 2 catalyst 35 tor volume.

Brief description of the drawings

Figure 1 refers to sulfur in the product up to 10-60 nm concentration of pores 40 of the molybdenum catalyst; 8403107 • λ 3 figure 2 refers to vanadium concentration in hydrocarbon product to concentration of molybdenum in micropores; Figure 3 relates nickel concentration in hydrocarbon product to concentration of molybdenum in micropores; Figure 4 shows concentration of vanadium in hydrocarbon product to macropore volume; Figure 5 concerns concentration of nickel in hydrocarbon product to macropore volume.

Description of the invention

It has been found that the demetallization and desulfurization of asphalt-containing hydrocarbons can be optimized by using a catalyst preparation with a controlled molybdenum charge and a controlled distribution of macropore volume and micropore volume. As used in the present specification, the term "macropore volume" refers to that portion of the total pore volume that is present in pores with a pore diameter in the range of 100 to 1000 nm, as determined by the test method described in "An Instrument For the Measurement of Fore Size Distribution by

Mercury Penetration "by Winslow and Shapiro in ASTM Bulletin, No. 236, Feb. 1959. The term" micropore volume "refers to that portion of the total pore volume contained in pores having a diameter in the range of 10-60 nm units, as determined by the nitrogen adsorption method described by EV Ballon, OK Dollen, in "Analytical Chemistry", Volume 32, page 532, 1960, each of the test methods being incorporated herein by reference and hereinafter referred to as the "Mercury Intrusion" method or "nitrogen adsorption" method.

An aluminum oxide support is used in the preparation of the new catalysts of the present invention. The aluminum oxide of the present invention may contain up to ten (10) percent by weight of other ingredients, such as silica. Typically, the support should have a total pore volume, as determined by mercury induction of 0.8 cm / g, nitrogen adsorption volume of 0.5 cmVg, a compacted bulk density of 0.5 g / ca, 95% of the nitrogen volume in pores with a diameter in the range of 10-60 nm is a BET specific surface area of 200 ml / g, a macropore volume of 0.5 ca / ml? catalyst volume, the pore diameters in the range of 200-40-600 nm being a micropore volume of 0.3 cm 3 / cm 2 catalyst volume urn.

84031 07 »4 4

Depending on the loading of the catalyst metals, the previously described support parameters can be adjusted to prepare the catalyst described below.

In the preparation of the catalyst, the alumina can be dried to remove any free water therefrom, usually at a temperature of 121 ° C for a period of time ranging from 1 to 24 hours. Thereafter, the support can be calcined at a temperature in the range of 427-871eC in an oxygen atmosphere for a period ranging from 1 to 24 hours.

The catalysts of the present invention contain molybdenum and at least one metal component selected from Group VIII. Molybdenum is deposited on the alumina support to provide, based on molybdenum trioxide, a load of at least 0.0005 g, preferably from 0.0006 to 0.0014 g, of molybdenum trioxide per square meter of catalyst surface. The Group VIII metal is supported on the support to provide a weight ratio of the Group VIII metal to molybdenum in the range of 0.10 to 0.50, preferably 0.18 to 0.38.

The preparation of the catalyst as described below will be particularly directed to a two-stage impregnation of the aluminum oxide support with the metals, although other preparation methods can be used. A single impregnation step can be used or the catalysts can be prepared by the extrusion method described in Journal of Catalysis 72, pages 255 to 265 (1981).

In the two-stage impregnation of the alumina support, alumina extrusion products can be mixed with an aqueous solution of salts such as ammonium molybdate, ammonium hepamolybdate, molybdenum pentachloride or molybdenum oxalate. The wet-impregnated alumina can then be dried by applying, for example, a temperature of 121 ° C for a period of 1 to 24 hours.

Thereafter, the alumina support impregnated with the molybdenum may be contacted with an aqueous Group VIII metal solution, such as nickel nitrate. The moist catalyst can then be dried in a second drying step at 121 ° C for a period of 1 to 24 hours. After the second drying step, the catalyst can then be calcined at a temperature in the range of 427 to 704 ° C for a period of 1 to 24 hours.

The metal components of the prepared hydrogenation catalyst 8403107 * * 5 can be used in sulfided or unsulfided form. When preparing the sulfided form, the catalyst can be pre-sulfided after calcination, or after calcination and reduction, according to art-known methods. For example, the sulfidation can be performed at a temperature in the range of 204-371 ° C at atmospheric or elevated pressures. Pre-sulfidation can be conveniently carried out at the start of an activation period under the same conditions as used at the start of the demetallization and desulfurization process. Mixtures of hydrogen sulfide 10 can be used in which the relative proportions of hydrogen and hydrogen sulfide are not critical. * Elemental sulfur or sulfur compounds, such as mercaptans or carbon sulfide, may be used in place of hydrogen sulfide.

The catalyst, as prepared and used in the demetallization and desulfurization process of asphalt-containing hydrocarbons of the present invention, will have a total pore volume, as determined by mercury penetration, of at least 0.5 µg / g, preferably in the range of 0.60-0.75 cm / g, a macropore volume of 0.02 to 0.20 cm ^ / cm ^ catalyst volume with the macropore diameters in the range of 100-1000 nm and a micropore volume of at least at least 0.12, preferably from 0.20 to 0.32 cm 3 / cm 2 catalyst volume. Preferably, the pore diameter of the macropore volume will be in the range of 200 to 600 nm and the macropore volume will be in the range of 0.035 to 0.075 ca ^ / cm ^ catalyst volume, and the pore diameters of the micropore volume will be in the range of 10 -40 nm. In addition, the catalysts of the present invention will have a nitrogen adsorption volume of at least 0.3, preferably from 0.40 to 0.50 cm 2 / g, a bulk density of at least 0.4, preferably from 0.50 to 0.70 g / cm 3, a specific surface area of at least 100, preferably 130-175 mm / g, and the micropore volume will comprise at least 70, preferably 80 to 95% of the nitrogen adsorption volume.

The effect of catalytic metal concentrations in specific pore structures was determined by preparing seven catalysts according to the previously described two-step method. The properties of the prepared alumina-supported catalysts and the properties of a commercial catalyst (No. 6) are listed in Table A below.

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«Fs * TABLE A

® Catalyst number_1_2_3_4_5 04 metal, wt% ίι · η)>

Ba 0.25 7 \ Cr - 4.0 3.0

Go - 1.0

Ni 6.0 1.3 1.0 0.5 3.0

Mo 2.0 4.0 5.0 8.0 8.0

Ti 5.0-

Calculated number of grams, MoOg / m ^ 0.00012 0.00025 0.00031 0.00050 0.00

Calculated number of grams 0.5 1.1 1.4 2.3 2.5

Mo in the range 10-60 nm per cm3 of catalyst

Macroporia volume ** 0.144 0.144 0.144 0.144 0.14 of the support, cm3 / cm3

Approximate pore diameter (nm) of 800 800 800 800 800 macro pores in the support

Sort weight, g / cm3 0.425 0.461 0.459 0.460 0.51 * The sample is a commercial hydrodesulfurization catalyst ** "" "total" PVstikstoP (compacted bulk density) | * «7

Catalysts 1-5 had large macropores (800 nm); catalysts 6 and 8 had no macropores and catalyst 7 had small macro pores (80 na). These catalysts were tested comparatively in a trickle bed pilot plant for de-metallizing-desulfurizing an asphalt-containing hydrocarbon operated at an LHSV of 0.4, a hydrogen pressure of 16750 kPa and a circulation rate of 89 Nm / hl and at a temperature of 399 ° C. The feed used was a desozed crude oil from Venezuela with the following analysis: density, API 9.1 sulfur, wt% 3.3 nitrogen, wt% 0.61 nickel, ppm 87 vanadium, ppm 360 carbon residue 15.2 The product quality data obtained after 8 days of operation are illustrated in Figures 1-3.

Figure 1 shows that the amount or size of the macroporosity does not affect the concentration of sulfur in the desulfurization product increasing as the concentration of molybdenum 20 in the pores with diameters of 10-60 nm is increased . At molybdenum, loads of at least 0.0005 g molybdenum oxide per square meter specific surface area, desulfurization is optimized. For these catalysts with a pore structure in the diameter range of 10 to 60 nm, the diffusion of organic sulfur molecules is not a limiting factor.

Figures 2 and 3 show the challenge of using large macropores (in pore diameters in the range of 100-1000 nm) in the demetallization of residual hydrocarbon fractions, although the macroporousness of catalyst 7 is substantially equivalent to that. of the catalyst 1 to 5, the demetallization efficiency of catalyst 7 was significantly less, demonstrating the significantly better diffusion capabilities of large macro pores.

Now that a need for large or "access" macropores has been identified to catalyze the large, metal-containing molecules in all parts of the catalyst particle, experiments were conducted to determine the amount of the macropore volume and the optimist size of the pores. and determine in the macro pore volume.

Since the propagation of macroporousness causes a decrease in the catalytically active microporousness per unit volume, the amount of macroporousness should be optimized to maintain the catalytic activity for demetallization and desulfurization.

A series of alumina supported catalysts were prepared using the above-described two-stage impregnation method. The properties of the prepared catalysts are described in Table 5 below.

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<=> TABLE B

Catalyst number _I_9 χρ n ^ 13 metal »wt%

O

^ Co ___________________ 8, TM -L »------------------------------------- o,

Pore volume, cm3 / g dlameter range, nm stlketofadsorptle ° »45 0.14 0.31 0.49 0, 0.08 0.04 0.07 0.06 0 ° I ° ° .13 0.04 0.11 0.12 0, i 7 ^ 0 O »11 0.03 0.08 0.14 0, <10 0.013 0.03 0.05 0.17 0,

Kwikind ringIng 1,68 lt2 ° ^ 68 ^ 00 0 »200J00 0,11 0,24 0,17 0,02 0, £ 00-600 0,01 0,04 0,04 0,02 0, 0,0 0 , 02 0.02 0.01 0,> 1000 0.01 0.03 0.04 0.01 0,

Density, g / cm3 0.396 0.429 0.359 0.396 0,

Number of grams in the diameter range 0.60 0.31 0 44 1 01 1 from 10-60 nm per 100 cm3 * »>

Macro pore volume in the diameter range 0.048 0.120 0 072 0 008 O

from 200-600 nm, cm3 / cm3 * * *

Product properties sulfur,% by weight 1.88 2.69 2.21 1.49 1,

Metals, ppm, ”1 31 38 42 30 42 v 125 145 123 128 174 9 \ 10

The catalysts of Table B were tested comparatively in the pilot plant previously described in a series of tests conducted at an LHSV of 0.5, a hydrogen pressure of 13,790 kPa and a circulation rate of 35.6 Hm / hl and at a temperature of 371 ° C. The feed used was a Mexican Maya atmospheric tower bottom fraction with the following analysis: density, API 7.5 sulfur, wt% 4.7 nickel, ppm 78 vanadium, ppm 408

The sulfur and metal concentrations of each of the test products are shown in Table B. Since linear relationships exist between metals in the product and the molybdenum content for a catalyst with identical amounts and dimensions of macroporosity and using the above product data from Table B, the curves of Figures 4 and 5 were developed for catalysts with 0.5 g of molybdenum in the pores with a diameter of 10 to 60 nm per 100 cm3 reactor volume urn and the macroporosity being in the range of 200 to 600 nm. Figures 4 and 5 show that when the amount of macroporosity is less than 0.03 cm3 / cm 2 reactor volume, diffusion is inhibited, while macroporosity greater than 0.08 cm / cm 2 catalyst volume has little effect on enlargement. of the diffusion. A range of macroporousness between 0.035 and 0.075 cm 2 / cnp catalyst volume optimizes the desired diffusion properties of the catalyst. Similar expansions for pores in the range of 600 to 1000 nm showed no recognizable trends, supporting the preferred pore size range of 200 to 600 nm in diameter for the macro pores.

Two catalysts are prepared to illustrate the effectiveness of the invention. Catalyst 17 was prepared by impregnating 236.0 g of a calcined 0.8 nm alumina extrusion with 360 ml of an aqueous solution containing 103.96 g of ammonium heptamolybdate (81.5% MO3) and 45.4 ml of ammonium hydroxide.

The mass was dried in an oven at 121 ° C and then calcined at 538 ° C for 10 hours. The calcined mass was then impregnated with an aqueous solution (326 ml) containing (a) 100.09 g of nickel nitrate hexahydrate and (b) 312.69 g of amine solution stabilized with 18.31% TiO2 “TiCl2. The mass was dried in an oven at 121 ° C for about 27 hours and finally calcined at 538 ° C for 10 hours.

8403 107 9 11

Catalyst 18 was prepared by impregnating 187.0 g of a calcined 0.8 mm alumina extruded product with 300 ml of an etcher containing solution containing 82.17 g of ammonium heptamol lybdate (81.5 Z MOO3) and 35 .9 ml of ammonium hydroxide. Mass 5 was dried in an oven at 121 ° C and then calcined at 538 ° C for 10 hours. The calcined mass was then impregnated with 275 ml of an aqueous solution containing (a) 79.05 g of nickel nitrate hexahydrate and (b) 248.22 g of an 18.01%

TiO2, TiCl2, stabilized aqueous amine solution.

The mass was dried in an oven at 121 ° C for about 27 hours and finally calcined at 538 ° C for 10 hours.

As suggested in the following Table C, the catalysts prepared have the desired amounts of macroporosity, 0.043, respectively. 0.041 cu? / Approx. catalyst-full union, and a microporosity of 0.20, respectively. 0.24 caP / cnP catalyst volume. The catalysts were tested comparatively in the pilot plant described above operated at an LHSV of 0.3, a hydrogen pressure of 16,500 fcPa and a circulation rate of 89 Nm? / Ml using a Merey Campo crude feed.

840 31 0 7 * ψ t 12 _TABLE 3_

Catalyst No. 17 18 Metals, wt%

Ni 5.0 5.0

Mo 14.0 14.0

Ti 8.5 8.5 S ti ks to f ad sor pt ion specific surface area, m3 / g 130.7 134.3 average pore diameter, A 120 132 total pore volume, cm3 / g 0.39 0.44

Pore volume in diameter ranges nm cm3 / g 40-60 0.028 0.021 20-40 0.104 0.116 10-20 0.175 0.205 <10 0.083 0.098

Kwi ing ing pore volume in diameter ranges nm cm3 / g total 0.63 0.54 200-400 0.033 0.049 400-600 0.033 0.010 600-1000 0.033 0.003> 1000 0.038 0.006

Compressed bulk density, g / cm3 0.653 0.704

Number of grams in the diameter range. 4.5 6.2 10-60 nm per 100 cm3

Number of grams ΜοΟβ / τη3 0.00100 0.00127

Microporousness in the diameter range 0.20 0.24 from 10-60 nm, cm3 / cm3

Macro porosity in the diameter range 0.043 0.041 from 200-600 nm, cm3 / cm3 8403107 ♦ 5 13

The feed analyzes and the product oils prepared in the experiments are given in the following Table D. For the catalysts 17 and 18, a desulfurization of 78.1 Z, respectively. 78.9 Z and a demetallization of 83.3 Z resp. 86.9 Z were obtained.

5 _TABLE D _

Analyzes Supply _Catalyst_

Merey Campo_17_18 density, API 17.8 20.9 22.5 sulfur, weight Z 2.28 0.50 0.48 10 nitrogen, weight Z 0.41 0.34 0.31 carbon residue according to 11.00 7, 05 6.67

Conradson, weight Z

nickel, ppm 55 17 15 vanadium, ppm 220 29 21 15 in n-pentane insoluble 12.22 5.86 4.13

constituents, wt

days in operation - 10 20 temperature, ° C - 391_391_

The configuration of the catalyst particle used in the demetalization-desulfurization process desirably has a high geometric specific surface area and a high bulk density as used in the reactor. Although not limited thereto, preferred embodiments have tapped cylinders and molded extrusion products of 0.8 mm.

The demetallization desulfurization reactions conducted in accordance with the process of the present invention are carried out on asphalt-containing hydrocarbons in the presence of the catalyst at a temperature which is maintained, after the relatively rapid increase in temperature which is added during starting. 30, in the range of about 316 to 454 ° C, preferably 343 to 427 ° C. The reactions are performed in the presence of non-combined hydrogen partial pressures in the range of 3450 to 27,580 kPa, preferably 10,350 to 15,250 kPa. Hydrogen gas (with at least a purity of 60 Z) is circulated through reaction zone at a rate of 17.8-178, preferably 35.7-106.8 Nm? per hl supply. A space velocity in the range of 0.1 to 5.0, preferably 0.2 to 2.0, fluid volumes of oil per volume of catalyst per hour (LHSV) is maintained in the reaction zone.

8403107 t 11. A process according to claim 10, wherein the catalyst also contains a Group IVS deposited metal thereon.

12. The method of claim 11, wherein the micropore volume of the catalyst is in the range of 0.20 to 0.32 cm 3 / cm 2 catalyst volurizer.

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Claims (10)

A catalyst containing molybdenum and a Group VIII metal supported on an alumina support, said catalyst having a total pore volume, as determined by mercury penetration, of at least 0.4 cm 2 / g, a macropore volume of 0.02 to 0.20 cm 3 / cm 3 catalyst volume and a micropore volume of at least 0.12 cm 3 / cm 3 catalyst volume. Catalyst according to claim 1, wherein the macropore volume is in the range of 0.035 to 0.75 cmVcm @ 2 catalyst volume and the 10 pore diameters of the macro pores are in the range of 200 to 600 nm. The catalyst of claim 2, wherein the molybdenum is deposited on the alumina support to provide a load of at least 0.0005 g of molybdenum trioxide per square meter of catalyst surface. The catalyst of claim 3, wherein the load is in the range of from 0.0006 to 0.0014 g of molybdenum trioxide per square meter of catalyst surface. Catalyst according to claim 3, wherein the micropore volume is 20 in the range from 0.20 to 0.32 cm 3 / cm 2 catalyst volume. Catalyst according to claim 5, wherein the pore diameters of the micropore volume are in the range of 10-40 nm. Catalyst according to claim 3 containing a group IVB metal on the alumina support. A process comprising contacting an asphalt-containing hydrocarbon containing sulfur and metals under hydrogenation conditions with hydrogen and a catalyst containing molybdenum and a Group VIII metal supported on an alumina support, said catalyst comprising a total pore volume, as determined by mercury penetration, of at least 0.4 cm 3 / g, a macropore volume of 0.02 to 0.20 cm 3 / cm 2 catalyst volume and a micropore volume of at least 0.12 cm 2 / cm 2 catalyst volume. The method of claim 8, wherein the macropore volume is in the range of 0.035 to 0.075 cm 3 / cm 3 catalyst volume and the pore diameters of the macropores are in the range of 200 to 600 nm. The method of claim 9, wherein the molybdenum is deposited on the alumina support to provide a load of at least 0.0005 g of molybdenum trioxide per square meter of catalyst surface. 8403107