JP3416177B2 - Method for producing highly active resid catalyst - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to a method for producing a catalyst carrier,
The present invention relates to a hydrocarbon hydrodesulfurization catalyst produced using the carrier, and a process for hydrodesulfurizing a hydrocarbon raw material using the above-mentioned catalyst. More particularly, it relates to a method for producing a porous catalyst substantially free of macropores (having a diameter of about 1000 Å or more) and containing at least one metal and / or metal compound of Group 6B and Group 8 elements. .

Even more particularly, it mainly comprises an alumina support component which is substantially free of macropores, has a specific micropore size distribution, and has the above-mentioned metals and / or
Alternatively, it relates to a catalyst containing a metal compound. It also relates to a hydrocarbon hydrodesulfurization process using the catalyst.

[0003]

The urgent need for desulfurization of hydrocarbon oils obtained from petroleum processes is known. When these feedstocks are burned as fuels in the usual way, the sulfur present in the hydrocarbons becomes a significant pollutant of the atmosphere in the form of sulfur oxide gases.

Typical conditions for the hydrodesulfurization process are a reaction zone temperature of 315-482 ° C. (600-900 ° F.), 14-211 Kg / cm ² G (200-300 p).
pressure of sig), 89~2672N per supply 1m ³ of oil
m ³ (500-15000 SCF per barrel) hydrogen supply and a catalyst such as nickel or cobalt and molybdenum or tungsten on a porous refractory support.

The problem recognized in the case of hydrodesulfurization of heavy oils is that the effective catalytic activity, if the heavy oils contain organometallic compounds, is especially nickel and vanadium with impurities dissolved above about 10 to 20 ppm. It tends to fall relatively rapidly when it is a metal such as. These metal impurities are said to be deposited on the surface and pores of the hydrodesulfurization catalyst.

One approach to this problem of reduced metal impurity activity in hydrodesulfurization catalysts has been to alter the catalyst pore structure. However, the answer as to what pore structure is the best is not readily available, and in fact the contradiction remains in the answers proposed by the prior art. U.S. Pat. Nos. 4,066,574; 4,113,661; and 4,341,625 are hereafter referred to as Tam'574, Tam'6.
61, Tam '625, the contents of which are fully explained herein by reference, but considered inconsistencies in the art and suggested one answer.

The Tam patent discloses that a heavy metal feedstock, especially a residual feedstock, is hydrogenated using a catalyst prepared by impregnating Group 6B and Group 8 metals or metal compounds into a carrier containing alumina. It is disclosed to be desulfurized, wherein the carrier has a pore volume of at least 70% in the pores having a diameter of 80-150Å. A particularly excellent hydrodesulfurization catalyst was obtained by using the alumina carrier having the above pore size distribution from the viewpoint of an extremely low activity deterioration rate.

In Tam '661, the catalyst is prepared using primarily alpha-alumina hydrate having a size in the range of less than 500 microns and treating with a specific amount of monobasic acid. The acid and the resulting mixture are then at least partially neutralized by mixing with an aqueous solution of a nitrogen base, such as an aqueous ammonia solution. The solution contains 0.6 to 1.2 equivalents of base per equivalent of acid. The treated and neutralized product is optionally shaped, dried, calcined and converted to a catalyst support. Finally, the catalyst support is impregnated with the above metals.

If the catalyst and toms '574,' 661,
And the process of '625 could be improved to give the catalyst higher catalytic activity over time,
It is beneficial.

[0010]

SUMMARY OF THE INVENTION According to the present invention, there is provided a process for hydrodesulfurizing a hydrocarbon-containing feedstock comprising a metal, wherein the feedstock is hydrodesulfurized under conditions such that a carrier comprising alumina contains a Group 6B or 8 metal or metal compound. Contacting with a catalyst prepared by impregnating the carrier with pores having a diameter of 70 to 130Å accounting for at least 70 volume percent of the pore volume. The total pore volume of the carrier is about 0.5 to 1 cubic centimeter per gram,
Pores with a diameter of 300Å or more account for less than 5% of their pore volume, and pores with a diameter of 1000Å or more account for less than 2% of their pore volume.

The invention is based on the finding that unexpectedly active catalysts result from slight changes in the pore size distribution. In another aspect of the invention, a characteristic pore size distribution is obtained by improving the method of making the catalyst support.

Specifically, the catalyst is produced by the following. (A) A peptizable fine particle solid mainly containing alpha alumina hydrate is mixed with an acidic aqueous solution to obtain p
H Process up to about 3.0 to 4.5. (B) by mixing at least a portion of the mixed acid with an aqueous solution of a nitrogen base containing an amount of base in the range of about 0.2 to 0.5 equivalents per equivalent of the acid to the treated solid. Neutralize. (C) Forming a neutralized or partially neutralized solid. And (d) about 66 ° C to 927 ° C (150 to 1700 ° F)
The carrier is completed by drying and calcining the molded solid at a temperature in the range.

In another embodiment of this invention, reverse neutralization reduces the nitrogen base equivalent number of peptic acid, and the calcination temperature is reduced compared to Tam '661, and the residual oil is lower than prior art catalysts. To make smaller pore catalysts that are more active for the conversion of The catalyst of this invention produces a high quality, low nitrogen vacuum gas oil. It is especially useful for raw materials with relatively low metal content.

DETAILED DESCRIPTION OF THE INVENTION The catalytic process of this invention is primarily aimed at residual oil feedstock as opposed to gas oil feedstock. Residual oils usually have more than 10 ppm metal, whereas gas oils almost always have less than 10 ppm metal content. Thus, typical feedstocks for this invention are crude oil atmospheric distillation column bottoms (concentrated crude oil or atmospheric column residue) or vacuum distillation column bottoms (vacuum column residue). Metal is an organometallic compound,
Probably believed to exist in a porphyrin or chelate-type structure, the metal content referred to herein is calculated as parts per million of pure metal.

Alumina is the preferred support material used in the process of this invention, although alumina can be combined with other refractory support materials such as silica or magnesia. The alpha alumina hydrate preferably used in this invention is obtained from various markets such as Catapal or Versal. It's also Tam '66
It can also be prepared as described in 1.

The support material containing alumina must have the above pore size distribution to provide the catalyst according to the requirements of the present invention. Since the change in pore size distribution due to impregnation of the support with Group 6B and Group 8 metal compounds is small, the pore size distribution of the alumina support used to form the final catalyst is substantially the same as that of the final catalyst. Are the same. Relatively pure alumina is obtained from various sources such as spray dried, amorphous or crystalline hydrate powder. These materials are suitable for extrusion when mixed with water immediately after the extrusion aid is added.

Two commonly used auxiliaries are strong mineral acids or combustible organic lubricating oils. The former usually gives a high density extrudate and the latter leads to a pore size distribution which substantially comprises a micropore volume, both of which are unacceptable in the resid desulfurization catalyst support according to the invention. The Tam patent, cited above, found that such materials were 97%
The above discloses a process that can be used to obtain a suitable low density alumina, which usually has a pore volume of 99% or more. It is in the region of pore diameters less than about 500Å.

In the present invention, the method of the Tam patent is improved by a unique improvement of the manufacturing method, and 70% of the pore volume in the pores has a pore size distribution having a diameter of 80 to 150Å, resulting in 70% in the pores. % Pore volume moves to a pore size distribution with a diameter of 70-130 Å. As pointed out in Tam'661, acid treated microparticulate solid alumina monohydrate is about 0.6 per equivalent of acid already added.
It is partially neutralized by adding an aqueous solution of a nitrogen base containing an amount of base in the range of 1.2 equivalents to the treated solid. This method is sometimes known as "back titration". The back titration is about 0.2-per equivalent of the previously added acid.
It is an aspect of this invention to work with a solution of a nitrogen base containing an amount of base in the range of 0.5 equivalents.

To make an alumina carrier or support with a pore size distribution in accordance with the requirements of the present invention, the alumina is a suitable monobasic acid, preferably nitric acid, or its equivalent as described above (Tum '661), for example. It must be treated with hydrochloric acid, hydrofluoric acid and hydrobromic acid.

As has been observed, acid treated alumina is satisfactory for the preparation of the final catalyst which is substantially free of macropores. However, it is unsatisfactory for producing a catalyst carrier having an appropriate pore volume used for preparing a residual oil desulfurization catalyst.
Satisfactory residual oil desulfurization catalyst carrier and catalyst is at least 0.5 m
It should have a pore volume of 1 / g, preferably at least 0.65 ml / g. Generally, if the micropore distribution and macropore content are satisfied, the larger the pore volume, the longer the catalyst life. To achieve the useful pore volume required for the final support and catalyst and to provide a suitable micropore distribution, a significant portion of the acid mixed in the treated feed is nitrogen base. Neutralized with and it must be mixed well with the feed by vigorous stirring.

As used herein, "nitrogen base" means a base of the formula: Ie R ₃ N and the corresponding hydroxide R
_{In 3} HNOH, the R groups are the same or different, and are selected from the group consisting of hydrogen and alkyl groups having 1 to 3 carbon atoms. Aqueous ammonia solution is preferred.

The prior art recommends that "each equivalent of acid used in the process usually requires at least about 0.6 equivalents of base". It is claimed that the prior art has a gradual advantage up to the point that large relative amounts of base may be used for neutralization. After that, larger relative amounts are undesirable. According to Tam'66, good results are generally obtained for the final carrier when the relative amount of base in the aqueous solution per equivalent of acid is in the range of about 0.6 to 1.2 equivalents, and this ratio is about 1: 1. The carrier obtained when it is .6 is usually unsatisfactory.

For the improved high activity bottoms catalyst, the relative amount of base in the neutralized aqueous solution per equivalent of acid is about 0.2 to 0.
It is a discovery of this invention that it should be in the range of 5 equivalents, preferably about 0.35 equivalents or more per equivalent of acid.

The properties of the mixture resulting from the neutralization of the treated alumina depend on its volatile content. It is either a free-flowing solid or a viscous paste. The preferred form required for use as an extrusion feed is a flowable solid having a volatile content of 50-70% by weight. The term "volatiles" as used herein means 480 ° C (90
Material released during high temperature drying above 0 ° F.

Various molding methods can be used to form the catalyst support precursor from the treated and neutralized solids. Preferably extrusion is preferably used for molding. In the manufacture of the final carrier, the drying and calcination steps of existing methods are typically about 65-815 ° C (150-170 ° C).
0 ° F), preferably 565-815 ° C
It is carried out at a temperature in the range of (1050 to 1700 ° F). The drying step is usually about 65-260 ° C (150-5
00 ° F. and drying followed by calcination in a dry or humidified atmosphere at about 260-815 ° C. (5
At temperatures in the range of 00 to 1700 ° F), preferably at temperatures of 565 to 815 ° C (1050 to 1700 ° F), and most preferably less than 760 ° C (1400 ° F).

The process is preferably such that more than 98% of their pore volume has a region of micropores, and in particular pores with diameters in the range 70 to 130Å have at least 70% of the total pore volume. A reasonably low density, mainly alumina, catalyst support having less than 5% of the total pore volume of pores with a diameter of 300 Å or more and less than 2% of pores with a diameter of 1000 Å or more Bring about the manufacture of. Table 1 gives a typical distribution of pore volume between each pore diameter in the prior art catalysts described in Tam'661, '574, and' 625. Table 2 gives a typical pore volume distribution between each pore diameter of the catalyst of this invention.

It is assumed that the pore volume described here is the volume of liquid adsorbed on the pore structure of the sample at saturated vapor pressure, and that the adsorbed liquid has the same density as the bulk density of the liquid. The liquid used for this assay was liquid nitrogen. A method for measuring the pore volume by physical adsorption of nitrogen is described in D. H. Everett and F.M. S. Ston
e, Colstrom Research Societ
Minutes of y's 10th Symposium (Proceedi
ngs of the Tenth Symposos
m of the Colstrom Research
Society), Bristol, Englan
d: Academic Press, March 1958,
pp. 109-110.

[0028]

[Table 1]

[0029]

[Table 2]

The hydrocarbon hydrodesulfurization catalyst of the present invention comprises at least one hydrogenating agent, preferably a combination of two such agents. Metals and / or metal compounds, especially sulfides and oxides of Group 6B (especially molybdenum and tungsten) and Group 8 (especially cobalt and nickel) of the Periodic Table of the Elements, are generally satisfactory catalyst agents, and of the present invention. It is contemplated for use with a substantially macroporous support made by the method.
A combination of cobalt, nickel and molybdenum catalysts is preferred.

The catalytic agent required for this catalyst composition can be incorporated into the calcined support by any suitable method, in particular by the impregnation methods commonly used in the catalyst preparation art. A particularly outstanding catalyst is that the alumina used not only has the pore size distribution required by this invention, but the catalyst is a single step of alumina using a solution of a cobalt or nickel salt and a heteropolymolybdic acid such as phosphomolybdic acid. It has been discovered that it is obtained when made by impregnation.

The following examples illustrate methods of making the catalysts of this invention.

[0033]

Example A Preparation of Catalyst Support 60% Catapal Alumina and Versal 250
Alumina raw material consisting of 40% alumina is deflocculated with 7.6% nitric acid and reverse neutralized with 35% ammonium hydroxide,
A volatile content of 63% by weight was given. Specifically, 1260
g Catapal and 840 g Versal on a volatile-free base at 54.5 ° C.-60 ° C. (130-14
Temperature of 0 ° F. and 228 g of concentrated nitric acid and 1
515 g deionized water was added at 150 cc / min to bake and mixed in a mixer for 15 minutes or until pasty. 20 g of paste was slurried with 80 cc of deionized water and its pH was 3.4.

55 g of concentrated ammonium hydroxide (58 wt% ammonium hydroxide) was mixed with 1145 g of deionized water and added to the mixer at a rate of about 150 cc / min, followed by a further 15 minutes of mixing. Volatile content is 6
It was 1.9% by weight. Paste temperature is 56 ℃ (133
° F). The paste is 50 mm (2 inc
Extruded in h) using a 1 mm (0.039 inch) cylindrical die. The extrudate was air dried and heated in a 120 ° C (250 ° F) oven for 2 hours. It was then heated at 400 ° F (205 ° C) for an additional 2 hours.
The recovered weight was 2345.5 g. The dried extrudates were calcined for 1 hour at 760 ° C (1400 ° F) with dry air at a rate of 28.3 liters / hour (1 ft ³ / hour).

The finished particles had the following properties. Particle size: 0.808 mm (0.0318 inch); Particle density: 1.056 g / cc; Total pore volume: 0.6188
cc / g; surface area 185 m ² / g. The support material was then impregnated with nickel and molybdenum by the following method. A mixture of molybdenum oxide dissolved in ammonium was acidified to pH 2.8 with phosphoric acid and nickel nitrate hexahydrate was added. The support was impregnated with the mixture to make the catalyst. Catalyst is 120 ℃ (25
Dried at 0 ° F. for 2 hours and 205 ° C. (400 ° F.) for 6 hours. It is then 0.566m ³ / h (20ft
⁴ at 232 ° C (450 ° F) with dry air at ³ / hr)
Hours, 400 ° C (750 ° F) for 4 hours, 510 ° C (9
It was calcined at 50 ° F for 5 hours. The final catalyst contained 8.62 wt% molybdenum, 3.16 wt% nickel, and 1.93 wt% phosphorus. Intermediate pore size is 111Å
Which was smaller than the prior art catalyst. Surface area is 1
It was 59 m ² / g. See FIG.

[0036]

Example B: The catalyst of Example A was prepared analogously by conventional techniques (Table 1 and FIG. 2 ... Tam '57.
4, '625,' 661) and the standard activity test. In this test, the conversion catalyst was charged to the reactor under a standard commercial demetallization catalyst bed and both catalysts were pre-sulphided with dimethyl disulfide. They were then mixed with 405 ° C + (760 ° F +) Arabian heavy resid and 0.
35 LHSV and 140 Kg / cm ² (2000 ps
i) 5000 SCF / bb1 (874 Nm ³ under total pressure)
/ M ³ ) with a 1-pass hydrogen flow. The layered catalyst system is 370 ° C to 400 ° C (700 to 750 °
F) in the temperature range and 0.35 hr ⁻¹ LH
Tested over 750 hours at feed rates ranging from SV to 0.50 h ⁻¹ LHSV.

The light gas stripped liquid product from the reaction is ASTM based on micro carbon residue (MCR).
Tested according to D4530-85. Figure 3 shows 55% M
The calculated temperature required to maintain CR conversion is shown. The results shown in FIG. 3 show that the catalyst of this invention is significantly more active than the reference catalyst, as indicated by the lower reactor temperature required to maintain the target MCR conversion.

[Brief description of drawings]

FIG. 1 is a diagram showing a distribution of pore diameters of a catalyst of the present invention.

FIG. 2 is a diagram showing a distribution of pore diameters of a conventional catalyst.

FIG. 3 To achieve a 55% Micro Carbon Residue (MCR) when feeding 404 ° C. + (760 ° F. +) Arab heavy atmospheric residue at a liquid hourly space velocity of 0.35. It is a figure which shows the required reactor temperature.

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Claims (11)

(57) [Claims] 1. A porous support is impregnated with an aqueous solution containing at least one catalyst agent or catalyst precursor selected from Group 6B and Group 8 compounds that is thermally decomposed into metal oxides,
A process for preparing a highly active catalyst for hydrodesulfurization of heavy oil, which comprises drying and calcining the resulting impregnated carrier, said carrier comprising: (a) predominantly alpha-alumina hydrate. Ri by the fact that the deflocculation properties particulate solid mixing process with an acidic aqueous solution containing
3 . A nitrogen base having a pH of 0 to 4.5, and (b) at least a portion of the mixed acid containing an amount of base in the treated solid in the range of 0.2 to 0.5 equivalents per equivalent of the acid. neutralized by mixing the aqueous solution, (c) shaping the neutralized or partially neutralized solid, and (d) shaped solid 6 6 ℃ ~927 ℃ (150
Produced by completing the carrier by drying and calcining at a temperature in the range of ~ 1700 ° F), the carrier having a pore volume of at least 0.5 cubic centimeters per gram, At least 70% of the pore volume has a pore diameter in the range of 70 to 130Å, less than 5% of the pore volume in the pore has a diameter of 300Å or more, and less than 2% of the pore volume of the pore. A manufacturing method characterized in that the volume has a pore diameter of 1000 Å or more. Wherein at least 80% of the pore volume in the catalyst pores with a diameter of 70～130A, The method of claim 1. 3. The catalyst is further characterized in that the Group 6B and Group 8 compounds are selected from the group consisting of cobalt, nickel and molybdenum compounds.
The method of claim 1 . 4. Pore volume of less than 5% in the pores is 140Å
The method according to claim 1 , wherein the method has the above diameters. 5. The method of claim 1 , wherein pores having a diameter of 1000 liters or greater make up less than 1% of the pore volume. Wherein said acidic solution is nitric acid, hydrochloric acid, selected from hydrofluoric acid and hydrobromic acid, Process according to claim 1. 7. The alpha-alumina hydrate is 500
The method of claim 1 having submicron dimensions. 8. The nitrogen base is of the formula R ₃ N or R ₃ NHO.
A process according to claim 1 wherein H is selected and all radicals are the same or different and are selected from the group consisting of hydrogen and alkyl radicals having carbon atoms in the range from 1 to 3. 9. A solution of the aqueous solution of a cobalt or nickel salt and heteropoly molybdate, the impregnation is carried out in a single step, A method according to claim 1. 10. The catalytic agents or catalyst precursor comprises nickel and molybdenum, further characterized in that the catalyst comprises nickel and molybdenum by 3 and 9% by weight are respectively the method according to claim 1 . 11. A solution of the nitrogen base is equivalent to the acid.
0 . The method of claim 1 , comprising an amount of base less than 35 equivalents.