JPH0687977B2 - Method for producing catalyst composition for catalytic cracking of heavy oil - Google Patents

Description

TECHNICAL FIELD The present invention relates to a catalyst composition for catalytic cracking of hydrocarbons, more specifically vanadium, nickel, iron,
It is used for catalytic cracking of heavy hydrocarbon oil containing a large amount of heavy metals such as copper, exhibits excellent metal resistance, maintains high cracking activity and high gasoline selectivity for a long time, The present invention relates to a method for producing a catalyst composition capable of suppressing production to a low level.

[Conventional technology]

Catalytic cracking of hydrocarbon oils is originally intended for the production of gasoline, and the catalyst used for this must naturally have high cracking activity and high gasoline selectivity. Metal resistance is required for the catalyst. The deterioration of petroleum circumstances in recent years has led to the situation that low-grade heavy hydrocarbon oils represented by residual oils containing heavy metals such as vanadium, nickel, iron, and copper have to be used as raw materials for catalytic cracking. Invited. This makes the metal resistance of catalytic cracking catalysts even more important.

Generally, in the catalytic cracking of heavy hydrocarbon oils, metal contaminants contained in the feedstock deposit on the catalyst, which causes the catalytic cracking activity and gasoline selectivity to decrease more or less. Therefore, catalytic cracking catalysts currently in commercial use, typically catalytic cracking catalysts in which a zeolite is dispersed in a porous inorganic oxide matrix, are tentatively satisfactory even if some metal is deposited. It is usually provided with metal resistance enough to maintain the catalytic performance. However, when the above-mentioned low-grade heavy hydrocarbon oil is catalytically cracked using this kind of catalyst, a large amount of metal contaminants are contaminated with it, and therefore a large amount of metal is also present in the catalyst. Deposits, which accelerates the dehydrogenation reaction, increases the production of hydrogen and coke, and may even destroy the crystal structure of zeolite, so that the original purpose of catalytic cracking cannot be fulfilled.

Under these circumstances, as a countermeasure when low-grade heavy hydrocarbon oil with a large amount of metal pollutants is targeted for catalytic cracking,
Measures such as increasing the amount of the catalyst used to reduce the amount of deposited metal per catalyst particle, or adding an antimony compound to the feed oil to suppress a decrease in the activity of the catalyst caused by the deposited metal are taken. I've been. However, these operational countermeasures cannot be applied due to the high operating costs.
On the other hand, as a measure for the performance of the catalyst, it is known that the amount of zeolite dispersed in the catalyst is increased more than that of a conventional catalytic cracking catalyst. Also, U.S. Pat.
JP-A No. 2003-242242 describes that a zeolite-containing catalytic cracking catalyst contains a phosphorus compound to improve the metal resistance of the catalyst. Furthermore, in U.S. Pat.No. 4,363,720, in improving the metal resistance of the catalytic cracking catalyst,
The utility of zinc compounds is disclosed.

In addition, U.S. patents. No. 4,222,896 MgO-Al ₂ O ₃ -AlP
JP-A-59-150539 proposes a catalyst in which a zeolite is dispersed in a matrix of O ₄ , and JP-A-59-150539 discloses a catalyst in which zeolite is dispersed in a magnesia-containing alumina matrix.

[Problems to be solved by the invention]

Among the conventional catalytic cracking catalysts developed to improve the metal resistance of the catalyst, the catalyst with an increased zeolite content should be a commercially attractive catalyst because the zeolite itself is expensive. I can't.

Further, regarding the conventional catalytic cracking catalyst containing a magnesium component, magnesium which is a basic substance easily reacts with vanadium which is a kind of polluting metal and captures it. Therefore, the catalyst containing the magnesium component is certainly more durable against vanadium poisoning than the catalyst containing no magnesium component. However, since the durability against nickel poisoning is poor, the conventional magnesium-containing catalytic cracking catalyst does not always produce by-products of hydrogen or coke when treating heavy oil rich in nickel as a metal contaminant. It cannot be suppressed enough.

The present invention provides a method for producing a catalytic composition for catalytic cracking which exhibits excellent poisoning resistance not only to vanadium contaminants contained in feedstock oil but also to nickel contaminants.

[Means for solving problems]

The method for producing a catalytic composition for catalytic cracking according to the present invention is a fine spherical particle prepared by spray-drying an aqueous slurry containing a precursor of a porous matrix material and a crystalline aluminosilicate zeolite, and the particle is magnesium. Salt solution and pH 3.
After contacting under conditions of 0 to less than 8.5, a pH adjuster is added to the solution in contact with the particles to raise the pH above 8.5, then the particles are recovered from the solution, washed and dried. Characterize.

According to the method of the present invention, fine spherical particles are first prepared by spray drying an aqueous slurry containing a precursor of a porous matrix material and a crystalline aluminosilicate zeolite. As the crystalline aluminosilicate zeolite, any synthetic or natural zeolite can be used, and the synthetic zeolite includes mordenite, Y-type zeolite, ultra-stable Y-type zeolite, ZSM-type zeolite and the like. These crystalline aluminosilicate zeolites are used in a form ion-exchanged with any one of hydrogen, ammonium and polyvalent metal cations, like the zeolite component of the conventional catalytic cracking catalyst. In addition, a hydrosol or hydrogel such as silica, alumina, or silica-alumina is typically used as the precursor of the porous matrix material, and alumina particles, clay minerals, etc. should be added to this precursor. You can

In preparing the aqueous slurry for spray drying, the amount of crystalline aluminosilicate zeolite used is selected so that the final catalyst composition contains 5 to 70% by weight of crystalline aluminosilicate zeolite. Also, the amount of the precursor of the porous matrix material used is 20 to 90% by weight in the final catalyst composition.
Of porous inorganic oxides. Therefore, when alumina particles or a clay mineral is blended with the precursor, the above-mentioned amount "20 to 90% by weight" is an amount containing the alumina particles or the inorganic oxide derived from the clay mineral.

An aqueous slurry containing a precursor of a crystalline aluminosilicate zeolite and a porous matrix material, preferably further containing alumina particles and / or clay mineral, is a conventional method,
Spray dried. Since the fine spherical particles obtained by spray drying often contain an alkali metal that is a catalyst poison, the amount of alkali metal contained in the spray dried particles is small.
It is preferable to wash the Na ₂ O so as to be 1.0% by weight or less.

The spray dried, washed microspherical particles are then contacted with an aqueous magnesium salt solution under conditions of pH 3.0 to less than 8.5, preferably pH 5.0 to 7.0. At the time of contact
If the pH is less than 3.0, the crystal structure of the crystalline aluminosilicate zeolite in the particles may be destroyed, and if the pH is 8.5 or more, the magnesium salt in the liquid will precipitate, so make sure to sufficiently introduce the magnesium component into the particles. I can't. As the magnesium salt aqueous solution, an aqueous solution of magnesium chloride, sulfate, nitrate or the like can be used, and the concentration thereof is suitably in the range of 0.05 to 25% by weight in terms of MgO.

Generally, the contact between the magnesium salt aqueous solution and the particles is such that the particles are immersed in the magnesium salt aqueous solution having a pH value in the above range at room temperature or under heating, and the magnesium component in the solution is introduced into the particles, which is converted into MgO. At 0.5-10% by weight of particles
Until the magnesium component corresponding to is introduced into the particles. Depending on the concentration of the magnesium salt aqueous solution, the above-mentioned amount of magnesium component can be introduced into the particles by keeping the particles in contact with the solution for at least 2 minutes.

The amount of magnesium component introduced into the particles is 0.5 in terms of MgO
If it is less than wt%, the metal resistance of the final catalyst composition is poor and hydrogen and coke by-products in the catalytic cracking process cannot be sufficiently suppressed. Further, when the amount of magnesium component is 10% by weight or more in terms of MgO, the crystalline structure of the crystalline aluminosilicate zeolite in the catalyst during the use of the final catalytic composition in the usual catalytic cracking process. , Is destroyed by the excess magnesium component, thus reducing the activity of the final catalyst composition.

After the intended amount of magnesium component has been introduced into the particles, a pH adjusting agent is added to the solution in contact with the particles to bring the pH of the solution to 8.5 or above, preferably 9.0 to 11.0, more preferably 9.5 to The magnesium component introduced into the particles is precipitated in the form of magnesium hydroxide by raising the temperature to a range of 10.5. The pH adjusting agent used for precipitation of magnesium hydroxide is a basic compound such as ammonia, an amine compound, calcium hydroxide or barium hydroxide, and these are usually used in an aqueous solution. However, hydroxides of alkali metals such as NaOH are poisonous to the catalyst and are not suitable as pH adjusters. A particularly preferred pH adjuster is an aqueous solution containing ammonium ions such as ammonia and amine compounds.

The particles with magnesium hydroxide deposited on the surface or inside are then recovered from the solution, washed and generally dried. Thus, crystalline aluminosilicate zeolite is 5 to 70% by weight, porous matrix material is 20 to 90% by weight,
A catalyst composition containing a magnesium component in an amount of 0.5 to 10% by weight in terms of MgO can be obtained. Then, this catalyst composition is calcined prior to being used in the catalytic cracking process, as is the case with the catalyst composition produced by a conventional method.

The catalytic composition for catalytic cracking produced by the method of the present invention exhibits excellent performance even when a relatively high-grade heavy hydrocarbon oil having a low content of metal pollutants is used as a feedstock. The superiority of the catalyst composition is most remarkable when the feedstock is a low-grade heavy hydrocarbon oil containing a large amount of metal contaminants. It is known that the catalytic composition for catalytic cracking containing a magnesium component has durability against vanadium poisoning, but the catalyst produced by the conventional method has the magnesium component dispersed in the matrix. However, it has poor durability against nickel poisoning. In contrast to this, the catalyst prepared according to the method of the present invention is, as shown in FIG. 1, because the magnesium component is concentrated on the surface of the catalyst particles, so that the catalyst is naturally not poisoned by vanadium. It is considered that it also exhibits excellent durability against nickel poisoning.

Next, the present invention will be described more specifically by way of examples.

Example 1 Commercially available No. 3 water glass was diluted with water to a SiO ₂ concentration of 12.73%, and this water glass solution and sulfuric acid having a concentration of 25% were added at 20 / min and 5.
Both were mixed while continuously pouring into a container at a rate of 6 / min for 10 minutes to obtain silica hydrosol (X). Kaolin corresponding to 45% by weight of the final catalyst was mixed with this silica hydrosol, and further an aqueous slurry of ammonium-exchanged Y-type zeolite was mixed so that the amount of zeolite was 30% by weight of the final catalyst, Hot air temperature 220
Spray dried at ° C. Then, the dried particles were washed and then dried again to obtain fine spherical particles. This is designated as catalyst A.

Next, 500 g of catalyst A was mixed with 2500 g of an aqueous magnesium chloride solution having a MgCl ₂ concentration of 1.17 wt% and a liquid temperature of 60 ° C., and stirred at pH 5.5 for 10 minutes. Then, 650 g of 15 wt% ammonia water was added to this suspension slurry to adjust the pH of the solution to 9.5.
And held for 10 minutes. Then, the particles in the liquid were collected by filtration, washed, and then dried at 110 ° C. for 15 hours to obtain a catalyst B. This catalyst contained 2.29 wt% magnesium component in terms of MgO.

Also, except that the concentration, pH, etc. of the aqueous magnesium chloride solution used were changed as shown in the following table,
C, D, E, F were prepared.

Example 2 Catalyst B except that 1000 g of 10 wt% aqueous tetraethylamine solution was used instead of 650 g of 15 wt% aqueous ammonia.
A catalyst G was prepared in exactly the same manner as the preparation of. This catalyst
It contained 2.16 wt% magnesium component in terms of MgO.

Example 3 A catalyst H was prepared in exactly the same manner as the preparation of the catalyst B, except that an aqueous magnesium nitrate solution was used instead of the aqueous magnesium chloride solution. This catalyst contained 2.0 wt% of magnesium component in terms of MgO.

Comparative Example 1 Silica hydrosol (X) obtained in the same manner as in Example 1
Was mixed with an aqueous MgCl ₂ solution containing magnesium in an amount such that a final catalyst containing magnesium component of 5.3 wt% in terms of MgO was obtained, and further kaolin corresponding to 42.6% by weight of the final catalyst was mixed. An aqueous slurry of ammonium-exchanged Y-type zeolite was mixed with this mixture so that the amount of zeolite was 28.5% based on the weight of the final catalyst, and the resulting mixture was spray-dried at a hot air temperature of 220 ° C. Next, the dried particles were washed and then dried again to obtain catalyst I.

Comparative Example 2 In this comparative example, a catalyst production example using a zeolite ion-exchanged with magnesium is shown.

The ammonium-exchanged Y-type zeolite used in Example 1 was mixed with an aqueous solution of magnesium chloride and ion-exchanged three times according to a usual method to obtain a Y-type zeolite having a magnesium exchange rate of 47.3%.

In order to make it possible to omit the step of washing and removing the alkali metal which is usually required in the process of preparing the catalyst, in this example, silica hydrogel was not used, but instead desalting with a SiO ₂ concentration of 5% prepared in advance was used. A silicic acid solution was used. This desalted silicic acid solution is mixed with kaolin corresponding to 45% based on the weight of the final catalyst, and further the magnesium-exchanged Y-type zeolite is mixed so that the amount of zeolite is 30% based on the weight of the final catalyst. The catalyst J was obtained by spray-drying the obtained mixture at a hot air temperature of 220 ° C. This catalyst is 1.25w in terms of MgO
It contained t% magnesium component.

Comparative Example 3 A catalyst K was obtained in the same manner as the catalyst B except that the step of increasing the pH by adding aqueous ammonia was omitted in the method for preparing the catalyst B in Example 1. This catalyst contained 0.76 wt% of magnesium component in terms of MgO.

Example 4 (Catalyst use example) The performance of each of the above catalysts A to K was evaluated by ASTM MAT.

First, in order to examine the metal resistance, nickel and vanadium were deposited on each catalyst as follows. That is, after each catalyst was previously calcined at 600 ° C. for 1 hour, a benzene solution containing a predetermined amount of nickel naphthenate and vanadium naphthenate was absorbed by each catalyst and then dried at 110 ° C.
It was baked at 00 ° C for 1.5 hours. After that, each catalyst was steam-treated at 770 ° C for 6 hours and pseudo-equilibrium was added to 600 ° C again.
It was baked for 1 hour. In addition, for each catalyst on which nickel and vanadium were not deposited, 770
Steamed at 6 ° C for 6 hours and then calcined at 600 ° C for 1 hour.

An ASTM MAT evaluation test was performed using each catalyst thus pretreated. The results are shown in Table-2. The reaction conditions are as follows.

Feed oil: Desulfurized vacuum gas oil Reaction temperature: 482 ° C. Space velocity: 16 hr ^-1 catalyst / oil ratio: 3 (weight) As shown in Table-2, catalysts B, C, D, which correspond to the catalyst composition of the present invention, E, G, and H maintain high cracking activity and high gasoline selectivity even when a large amount of metal is deposited, and even though they have high cracking activity, they can suppress the production rate of coke and hydrogen to low levels. it can. In contrast to this,
The catalysts I, J, K and the catalyst A of the comparative example have a high production rate of coke and hydrogen due to the deposition of a large amount of metal. Further, the catalyst F having a large amount of MgO has a low production rate of coke and hydrogen, but has a low conversion rate.

[Brief description of drawings]

FIG. 1 is a graph showing the results of measuring the distribution of Mg in the catalyst particles with an X-ray microanalyzer after the catalyst B prepared in Example 1 was calcined at 600 ° C. for 1 hour. FIG. 2 is a graph showing the results of measuring the distribution state of Mg in the catalyst particles with an X-ray microanalyzer after the catalyst H prepared in Comparative Example 1 was calcined at 600 ° C. for 1 hour.

Claims (3)

[Claims] 1. A fine spherical particle is prepared by spray-drying an aqueous slurry containing a precursor of a porous matrix material and a crystalline aluminosilicate zeolite, and the fine spherical particle is treated with an aqueous solution of magnesium salt to a pH of 3.0 to less than 8.5. After contacting under conditions, a pH adjuster is added to the solution in contact with the particles to raise the pH to 8.5 or higher, and then the particles are recovered from the solution, washed, and dried. A method for producing a catalyst composition for oil catalytic cracking. 2. The production method according to claim 1, wherein the pH adjuster is an aqueous solution containing ammonium ions. 3. The production method according to claim 1, wherein the amount of the magnesium salt impregnated in the spray-dried particles is 0.5 to 10% by weight of the particles in terms of MgO.