JPH0122818B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a catalyst for hydrodemetalization of petroleum-based hydrocarbon oils containing asphaltenes and 250 ppm or less of metals. In recent years, as the quality of feedstock oil has changed worldwide, the content of metals such as Ni and V, asphaltenes, and various organometallic compounds contained in oil has increased, and hydrodesulfurization targeting this type of heavy oil has increased. In reactions, hydrocracking reactions, etc., the lifetime of the catalyst is shortened due to clogging of the catalyst pores, so even the operating conditions have to be limited. Therefore, in order to maintain high hydrodesulfurization ability or high hydrogenation cracking ability, extend catalyst life, and enable stable operation, metals such as Ni and V contained in heavy oil are efficiently removed. There is a need for the development of catalysts that can remove these substances. The metals most commonly found in petroleum-based hydrocarbon oils such as atmospheric distillation residues, and hydrocarbon oils liquefied and recovered by known methods from tar sands, oil shale, etc., are nickel, vanadium, and iron. These metals exist in a free state as well as in considerable amounts in the form of metal porphyrins and the like in asphaltene and other polymers in hydrocarbon oils. These asphaltenes and metals have a very detrimental effect on various refining operations such as hydrodesulfurization, hydrocracking and catalytic cracking. In other words, these asphaltenes and metals not only poison each refining catalyst itself, but also cause blockages between the catalyst particles in the fixed bed reaction bed, or even if they do not cause blockages, they can cause uneven flow of hydrogen gas and hydrocarbon streams. It occurs in the catalyst layer and significantly reduces the efficiency of each reaction. As a result, the reactor may be stopped, the reaction may be carried out at a higher temperature than necessary, or the operating efficiency of the apparatus may be reduced. Therefore, in order to avoid such disadvantages, it is necessary to efficiently remove or reduce asphaltenes and metals prior to various purification operations. By the way, in order to hydrogenolyze asphaltene, the idea that a catalyst with a large pore diameter is effective because asphaltene has a high molecular weight and a large molecular size has been dominant in the industry. For this reason, most conventional catalysts have pore diameters that are unnecessarily larger than the pore diameter of the catalyst proposed in the present invention. Attempts are being made to prevent deactivation due to the precipitation of other metals. However, asphaltene in the residual oil thermally dissociates under high hydrogen pressure and high temperature and becomes a relatively small molecular weight, which enters the hydrogenation catalyst pores in a relatively small molecular weight state and starts the hydrogenation reaction. Conventional large pore diameter catalysts cannot necessarily be used in consideration of the mechanism of precipitation of heavy metals caused by decomposition of asphaltene or separately generated. The catalyst of the present invention uses γ-alumina as a carrier, which has easy to control physical properties, and unlike the various proposed raw materials with large pore diameters and low cost, such as iron powder and red mud, the catalyst of the present invention The conventional idea that large pores are sufficient for catalytic decomposition of asphaltene content has been changed, and now the idea is that the diameter and pore volume are sufficient to allow thermally dissociated asphaltene to diffuse into the pores. It has become concrete. That is, the catalyst of the present invention has a pore distribution measured by a nitrogen gas adsorption method, and the average diameter of pores in the range of 0 to 600 Å is 100 to 180 Å, and the pore diameter is within the average diameter ±20 Å. The total volume of the drilled hole with is 0
at least 60% of the total volume of pores with a pore diameter of ~600 Å, and the total volume of pores with a pore diameter of 50 Å or less is 10% of the total volume of pores with a pore diameter of 0 to 600 Å % or less, and the total volume of pores with a pore diameter of 200 to 300 Å is 5% or less of the total volume of pores with a pore diameter of 0 to 600 Å, and
The total volume of pores with a pore diameter of Å or more is 0~
It is less than 3% of the total volume of pores with a pore diameter of 600 Å. Furthermore, in the pore distribution of the catalyst of the present invention measured by mercury intrusion method, the average diameter of pores in the range of 62 to 600 Å is 100 to 170 Å, and the average diameter ±
The volume of pores with a pore diameter of 20 Å accounts for at least 70% of the pore volume between 62 and 600 Å, and the volume of pores with a pore diameter of 200 Å or more accounts for 5 to 15% of the pore volume between 62 and 600 Å. %It is in. Here, pore distribution measurement using nitrogen gas adsorption method
The pore distribution is determined by the BJH method, and the pore distribution is measured by the mercury intrusion method using a mercury intrusion type pore distribution measuring device model 220 manufactured by CALRO ERBA under the conditions of a contact angle of 130° and a surface tension of 473 dyn/cm ² . Further, the average diameter of the pores is a diameter corresponding to 50% of the pore volume determined from the pore distribution curve. In a catalyst having a pore diameter smaller than that of the catalyst of the present invention, the demetalization activity is significantly lower than that of the catalyst of the present invention, as is generally said. This is because even though the catalyst particles have a high specific surface area, their pore diameter is small and the pores on the outer surface of the catalyst particles are blocked by precipitated metals. Because of its high specific surface area and small pore diameter, it is initially highly active;
Start-up is possible at low temperatures, but as a result of this, the thermal dissociation of asphaltene substances, which the present inventors pointed out, becomes insufficient at lower reaction temperatures, and they do not diffuse into the catalyst pores while maintaining large molecular dimensions. Hydrodesulfurization reaction, hydrogenolysis, etc. occur at the pore entrance, causing pore blockage. On the other hand, regarding catalysts with pore diameters larger than the pore diameter of the present catalyst, an important fact that seems to be generally known but has been completely overlooked is that increasing the pore diameter increases the effectiveness of the catalyst. The problem is that the active surface area decreases. As a result, catalysts with larger pore diameters than the catalyst of the present invention have a lower hydrodesulfurization ability and a smaller metal deposition area, and in order to maintain stable activity, the reaction temperature must be increased. This will lead to undesirable results. A possible countermeasure to this problem is to increase the pore volume of the catalyst, but as the pore volume increases, the physical pressure strength of the catalyst decreases linearly, so there is a limit to this. Therefore, under high hydrogen pressure of asphaltene,
Catalysts having pore diameters larger than those of the present invention, which are designed from different considerations regarding size at high temperatures, generally have to have a small pore volume in order to maintain their compressive strength above a certain value. Since reactions such as hydrodesulfurization and hydrogenolysis occur on the effective active surface, the amount of metal that can be deposited is proportional to the active surface and pore volume. Therefore, it can be naturally understood that a catalyst with a large pore diameter and a small pore volume has a shorter life than the catalyst of the present invention. Taking these things into consideration, and further estimating the minimum compressive strength of a practical catalyst on a commercial basis to be 0.6Kg/mm,
Catalyst pore volume is 0.57-0.95cc/g, specific surface area is
The physical properties are limited to 170 to 220 m ² /g. In the present invention, when considering the reaction effect of one catalyst particle, it is necessary to have a pore structure that allows residual oil and asphaltene to effectively penetrate and diffuse into the internal pores of the catalyst particle, and at the same time In order to facilitate diffusion, it is necessary to increase the external specific surface area of the catalyst particles. That is, it is preferable to maintain the reaction activity by increasing the external specific surface area of the catalyst and increasing the effective size (volume/external specific surface area), and to prevent or slow down the clogging of pores due to metal precipitation. To this end, it is effective to make the shape of the extrusion-molded catalyst into smaller particles, or to increase the external specific surface area per particle weight by increasing the number of protrusions. Specifically, the catalyst is an extrusion-molded column whose cross section perpendicular to the extrusion axis has a trilobal or quadrilobal shape inscribed in a circle or ellipse of 1/8" to 1/32". I can do that. This produces the same effect as aggregating small catalyst particles, and increases the external specific surface area, increasing the activity of various hydrogenation reactions, including hydrodesulfurization and hydrodemetalization. . Furthermore, although these extrusion molded products appear to have low pressure resistance at first glance, an unexpected effect of increasing pressure resistance has been discovered. Furthermore, as is generally known, pressure loss can also be reduced by using these catalysts compared to cylindrical catalysts. The packing specific gravity of the catalyst of the present invention is 0.50 to 0.65 g/cc. A component of the catalyst of the present invention is γ alumina obtained from boehmite gel as a carrier material for the catalyst. Furthermore, in order to maintain hydrodemetalization activity and selectivity, the active ingredients include vanadium, Mo, W from group a of the periodic table, and Ni, Co, and Fe from group a of the periodic table.
At least one of the oxides mentioned above is present in an amount of 20 wt% or less, preferably 10 wt% or less, more preferably 0.5 wt% to 5 wt%, based on the total amount of metal oxides.
Supported by alumina. The amount of vanadium oxide is 20-80wt% of the total amount of supported metal oxides.
A range of is desirable. The role of the active component of a catalyst is to efficiently increase yield and selectivity, but deviation from these optimal ranges
leading to decreased yield and selectivity. In the present invention, catalyst components and compositions suitable for hydrodemetallation are selected with these considerations in mind. In general, the active components and composition of catalysts used in hydrotreating reactions such as hydrodesulfurization and hydrocracking reactions are not designed with consideration to hydrodemetalization ability, but are designed primarily for hydrodesulfurization. However, the catalyst support and active components are optimized for desulfurization ability, and no consideration is given to demetalization. That is, if excessive active ingredients and compositions are used to increase desulfurization ability, excessive demetalization reactions occur, resulting in precipitated metals accumulating at the pore entrances before being sufficiently diffused into the pores, resulting in blockage. No attention is paid to the fact that The present inventors have conducted various studies to suppress these hydrodesulfurization reactions and selectively cause hydrodemetalization reactions. As a result, the inventors have found that V and Ni in hydrocarbon oil are selectively attracted to and accumulated in the so-called self-sustained reaction. It has been found that metals can be efficiently removed by impregnating a small amount of a vanadium compound that produces a catalytic effect and further adding small amounts of Ni, Mo, and W to impart some asphaltene decomposition and hydrogenation activity. The catalyst of the present invention is characterized by having a function as a hydrodesulfurization catalyst due to the optimal combination of catalytic active components, composition, physical properties, and shape. Maximum effectiveness can be achieved by using it in combination with a hydrocracking catalyst. In this case, the hydrodesulfurization catalyst uses a γ-alumina carrier that is almost the same as the demetalization catalyst described above. On the other hand, the carrier for the hydrocracking catalyst is a carrier for the hydrodesulfurization catalyst mixed with a third component such as zeolite. The active metals for both the hydrodesulfurization catalyst and the hydrocracking catalyst include Mo and W from group a of the periodic table, Co from group a,
At least two types of oxides of Ni and Fe are used, and the total amount of the metal oxides is 30 wt% or less, preferably 20 wt% or less. The hydrodemetalization catalyst of the present invention is placed on a hydrodesulfurization catalyst or hydrocracking catalyst in a certain ratio as a so-called guard catalyst, and in the presence of hydrogen Ni, V By bringing a feedstock containing metals such as , Fe, organometallic compounds, and asphaltene into contact with the catalyst, hydrodemetallation and hydrodesulfurization or hydrocracking can be performed all at once. The preferred operating conditions for this method of using the hydrodemetalization catalyst are an average temperature of 340 to 450 in both the hydrodemetalization reaction zone and the hydrodesulfurization (or hydrocracking) reaction zone.
℃ Preferably 375-440℃, hydrogen partial pressure 40-250Kg/
cm ² preferably 70-240Kg/cm ² , hydrogen flow rate 500-
2000 Nm ³ /Kl and LHSV 0.1-5.0 hr ^-1 preferably 0.2-4.0 hr ^-1 . Furthermore, the ratio of the hydrodemetalization catalyst in combination with a hydrodesulfurization catalyst or a hydrocracking catalyst is 5 to 70 vol per volume.
% preferably 10 to 50 vol%. In the hydrodesulfurization reaction and the hydrocracking reaction, unexpectedly excellent effects are exhibited by using the hydrodemetalization catalyst of the present invention in combination. In summary, it is not always true that a catalyst with a large pore size is necessary for the hydrodemetalization reaction, as has been previously stated, and asphaltene is dissociated, as described above.
In order to efficiently remove the metals contained therein, catalysts with limited active components and physical properties are required. Since the catalyst of the present invention changes its active components and composition from a hydrodesulfurization reaction to a hydrodemetalization reaction, an excessive demetalization reaction does not occur at the pore entrance, and the pore size and pore size are limited. In conjunction with the volume, pore clogging does not occur, resulting in a longer catalyst life, and furthermore, it serves to protect the hydrodesulfurization catalyst and hydrocracking catalyst used in combination from metals, allowing them to maintain sufficient activity. Can be done. EXAMPLES In order to explain the present invention in more detail, Examples will be described below, but these examples are for illustration purposes only and are not intended to limit the present invention in any way. Example 1 93.0 kg of an aluminum sulfate solution with a concentration of 2.5 wt% as alumina is added to 80 kg of a sodium aluminate solution with a concentration of 5 wt% as alumina over about 10 minutes, and the final pH is adjusted to 7.2. This alumina slurry was filtered and approximately 120 kg of 0.2wt% ammonia water was extracted.
Pour water over it and wash off the sodium sulfate. Ammonia water was added to the alumina hydrate containing pseudo-boehmite obtained in this way, and the pH was adjusted to 10 or more.
Matured at 95℃ for 20 hours. This alumina hydrate is heated and concentrated using a kneader to obtain a hydrate. This product is molded into a trilobal shape with a size of 1/22" using an extrusion molding machine. This product is dried at 150℃ for 16 hours, and then at 550℃ for 3 hours.
The catalyst carrier (X) was obtained by firing. In order to support 1.5wt% of vanadium pentoxide and 1.5wt% of nickel oxide on 500g of carrier (X), 10g of ammonium metavanadate and 14.2wt% of nickel carbonate were added.
g was mixed with an appropriate amount of water and dissolved by heating at 95°C to obtain an impregnating liquid. After spraying and impregnating the carrier with this impregnating solution, it was dried while slowly raising the temperature from room temperature to 250°C, and then calcined at 550°C for 1 hour to prepare the catalyst (A).
I got it. Comparative Example 1 10wt% of clay minerals and fibrous organic compounds were added to the alumina hydrate obtained in Example 1 to form a hydrate again, which was then molded into a trefoil shape with a size of 1/22″ using an extrusion molding machine. and dried at 150℃ for 16hr, then dried at 550℃,
A catalyst carrier (Y) was obtained by firing for 3 hours. Molybdenum oxide 10.5wt% to 500g of carrier (Y),
Ammonium paramolybdate was used to support 1.23wt% of cobalt oxide and 0.7wt% of nickel oxide.
60.0g, cobalt nitrate 27.3g, nickel nitrate 15.7
An impregnating solution was prepared by adding and dissolving 277 g of 15% NH ₄ OH and 15% NH 4 OH in water. After spray impregnating the carrier with this impregnating liquid, it was dried while slowly raising the temperature from room temperature to 250°C, and then calcined at 550°C for 1 hour to obtain a catalyst (B). Comparative Example 2 A catalyst was prepared using 500 g of the carrier (Y) obtained in Comparative Example 1 using the same metal components and composition as in Example 1 and following the same procedure. This catalyst is designated as (C). In addition, the catalyst
(C) was a hydrodemetalization catalyst. Comparative Example 3 During the preparation of alumina described in Example 1, Example 1 was applied to a carrier obtained by performing each step including the alumina concentration in the same manner, except that the aging step was changed to 95°C for 10 hours.
It was prepared by the same procedure using the same metal components and composition. This catalyst is designated as (D). Table 1 shows the physical properties of the catalysts (A) to (D) described above.

【table】

[Table] Evaluation test example 1 Catalysts (A) to (D) were tested using a fixed bed flow type experimental device.
A hydrodemetalization activity test was conducted. For the activity test, 300g of catalyst was placed in a reaction tube with an inner diameter of 19.2mmφ and a length of 3000mm.
The reaction was carried out under the following reaction conditions. Pressure 150Kg/cm ² G LHSV 0.25hr ^-1 H ₂ /HC 700m ³ /Kl Temp 390°C Hydrogen concentration 90mol% AH.RC having the following properties was used as the raw material oil. Specific gravity (15/4℃) 0.99 Viscosity (at 50℃) 2900cst Residual carbon 15wt% Asphaltene content 8.2wt% Sulfur content 4.1wt% Nitrogen content 0.3wt% Metal content (vanadium + nickel) 130ppm Desorption after 50 hours from the start of the test The metal activity is shown in Table 2.

[Table] Evaluation test example 2 Using a fixed bed flow reactor, a life test of the hydrodesulfurization reaction was conducted using a combination of hydrodemetallization catalysts (A) to (D) and a commercially available hydrodesulfurization catalyst. Ivy. Inner diameter
A reaction tube with an inner diameter of 19.2 mmφ and a length of 19.2 mmφ and a length of 19.2 mmφ is directly connected to the guard catalyst reaction tube by filling a reaction tube with a diameter of 19.2 mm and a length of 1200 mm with 100 g of hydrodemetalization catalyst.
A 300 mm reaction tube was filled with 300 g of a commercially available hydrodesulfurization catalyst to serve as the main reaction tube for carrying out the hydrodesulfurization reaction. The reaction conditions and raw material oil were the same as those in Evaluation Test Example 1, except that the reaction temperature was adjusted within the range of 370 to 420°C in order to obtain a constant desulfurization rate. FIG. 1 shows the results of hydrodesulfurization reactions performed using combinations of each hydrodesulfurization catalyst and a commercially available hydrodesulfurization catalyst. As is clear from FIG. 1, the hydrodesulfurization catalyst (A) of the present invention exhibits the effect of significantly extending the life of the hydrodesulfurization activity when used in combination with a hydrodesulfurization catalyst.

[Brief explanation of drawings]

FIG. 1 is a graph showing the experimental results of Evaluation Test Example 2.

Claims (1)

[Scope of Claims] 1. A catalyst composition comprising vanadium and an oxide of at least one metal selected from Group A and Group A of the Periodic Table supported on a support consisting essentially of γ alumina, the catalyst composition comprising: Total amount of oxide is 10wt
% or less, and the pore characteristics of the composition satisfy all of the following conditions (a), (b), and (c). (a) The average diameter of pores in the pore diameter range of 0 to 600 Å in the pore distribution measured by nitrogen gas adsorption method.
100 to 180 Å, and the total volume of pores with a pore diameter of ±20 Å is at least 60% of the total volume of pores with a pore diameter of 0 to 600 Å, and the pore diameter is less than or equal to 50 Å. The total volume of pores with a pore diameter of 0 to 600 Å is 10% or less of the total volume of pores with a pore diameter of 0 to 600 Å, and the total volume of pores with a pore diameter of 200 to 300 Å is 0 to 600 Å. 5% or less of the total volume of pores with a pore diameter of 300 Å or more, and the total volume of pores with a pore diameter of 300 Å or more is 0 to 600 Å.
3% or less of the total volume of pores with a pore diameter of
The average diameter of the pores ranges from 62 to 600 Å.
170 Å and the total volume of pores with a pore diameter of average diameter ± 20 Å accounts for at least 70% of the pore volume of 62 to 600 Å, and the volume of pores with a pore diameter of 200 Å or more accounts for at least 70% of the pore volume of 62 to 600 Å The pore volume of 5~
(c) the specific surface area is 170-270 m ² /g and the pore volume (600 Å or less) is 0.57-0.95 ml/g; 2. the catalyst composition is an extruded column; The shape of the cross section perpendicular to the extrusion axis direction is 1/
It is a three-lobed or four-lobed shape inscribed in a circle or ellipse of 8" to 1/32", and the catalyst closest packing specific gravity is 0.50.
2. Catalyst according to claim 1, characterized in that the amount is 0.65 g/ml. 3. The catalyst according to claim 1, wherein the metals in group a of the periodic table are Mo and W, and the metals in group a are Ni, Co, and Fe.