JP2933708B2 - Modified Y-type zeolite, process for producing the same, and catalyst composition for catalytic cracking of hydrocarbons using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a modified Y-type zeolite having a characteristic pore distribution, a method for producing the same, and a catalyst composition for catalytic cracking of hydrocarbons using the same. More particularly, an improved Y-type zeolite suitable for use in the catalytic cracking of hydrocarbons, especially heavy hydrocarbons such as hydrogenated atmospheric residues, a method for producing the same, and a hydrocarbon contact using the same The present invention relates to a decomposition catalyst composition.

[Conventional technology and problems]

Since catalytic cracking of hydrocarbons is intended to produce gasoline, the zeolite used must, of course, have high cracking activity and high gasoline selectivity. However, a catalyst having a high cracking activity generally generates a large amount of coke and gas, which is a common problem with a catalytic cracking catalyst.

By the way, recent changes in the supply situation of crude oil have resulted in the use of low-grade heavy hydrocarbon fractions containing heavy metals such as vanadium, nickel, iron and copper, typically residual oil, as feedstock for catalytic cracking. It has caused a compelling situation. However, when catalytic cracking of low-grade heavy hydrocarbons occurs, the degree of metal contaminants contained in the feedstock precipitate on the catalyst increases. Be impaired. In addition to this, the metal deposited on the catalyst accelerates the dehydrogenation reaction, and thus has the disadvantage of promoting the production of coke and gas.

The following are examples of thermally excellent Y-type zeolites that exhibit high cracking activity when used as a catalytic cracking catalyst for hydrocarbons.

JP-B-42-8129 discloses that the crystalline, forgedite is continuously trans-substituted with a solution of a salt of a nitrogen base until the alkali metal content is reduced to 5% by weight or less. About 200 to 820 ° C
The composition is cooled for about 0.1 to 12 hours at a temperature of about 0.1 to 12 hours and continuously trans-substituted with a solution of a salt of a nitrogen base until the alkali metal content drops below 1% by weight, 540-820 ° C. A method for producing a synthetic ultra-stable zeolite, characterized by calcining at 0.1 ° C. for 0.1 to 12 hours and cooling and recovering the ultra-stable zeolite product.

Japanese Patent Publication No. 46-9132 discloses that when an ammonium-type crystalline aluminosilicate having a molar ratio of silica to alumina of more than 3 is fired into a corresponding hydrogen-type, the firing of the aluminosilicate is rapidly performed. Disclosed is a method for producing a catalyst composition having high heat and moisture stability for hydrocarbon conversion, which comprises carrying out base exchange of an aluminosilicate thus calcined with an ammonium salt in the presence of a steam stream.

JP-B-47-8044 discloses that in calcining a hydrogen-type crystalline aluminosilicate having a silica / alumina ratio of at least 3, calcining is carried out at a temperature of 450 ° C. to 850 ° C. Aluminosilicate and 450-8
A method for producing a hydrogen-type aluminosilicate catalyst composition which is stable against hydrothermal action, comprising calcinating the aluminosilicate, wherein the reaction is carried out at a temperature of 50 ° C. is disclosed.

The Japanese Patent Publication No. Sho 57-16925, ammonium containing sodium about 0.6 to 5 wt% as Na ₂ O - calcined sodium -Y zeolite, the calcined about from 315.6 to 898.9 ° C.
At a temperature of (600-1650 ° F) at least about 0.014 kg / cm ² (0.2
psi) and carried out for a period of time sufficient to significantly reduce the size of the zeolite and the unit cell to a value of about 24.40-24.64 °, and the calcined zeolite is
Further ammonium ion exchange treatment is performed under conditions adjusted to replace the remaining zeolite and sodium ions by at least about 25% with ammonium ions to obtain a final product containing less than about 1% by weight of Na ₂ O. A method for producing a hot water-stable and ammonia-stable Y zeolite composition is disclosed.

Japanese Patent Publication No. 44-31948 discloses that a molecular sieve is treated in a gas phase containing 5% or more of water at a high temperature for a time sufficient to remove at least some alumina tetrahedrons from the crystal lattice of the molecular sieve. Enhancing the alumina into an amorphous phase in the molecular sieve and contacting the heat-treated molecular sieve with an agent suitable for removing alumina, thereby substantially retaining at least the crystallinity of the molecular sieve. Silica /
A step of producing an aluminosilicate zeolite molecular sieve having an alumina molar ratio in combination with a step of producing a silica / alumina in a crystal lattice of a molecular sieve type crystalline aluminosilicate zeolite in which the molecular sieve is at least partially in a hydrogen form. A method for increasing the molar ratio of is disclosed.

JP-A-51-133195 discloses: (a) a process for producing faujasite-type zeolites which have been stabilized by replacement and at least one high-temperature calcining step; (C) removing at least 15% of the aluminum atoms from the tissue by treating with a rare mineral acid; and (c) washing, drying, and recovering the obtained product. And c) increasing the silica / alumina ratio of the faujasite-type zeolite from about 35 to 6 to about 7 to 20.

JP-A-60-46916 discloses that (a) a faujasite-type zeolite containing an alkali metal or an alkaline earth metal is treated with an aqueous solution of an ammonium salt under conditions of pH 4.5 to 5.0 to form a zeolite. (B) ion-exchanging about 50 to about 67% of the alkali metal or alkaline earth metal to ammonium; (b) calcining the obtained ammonium-exchanged faujasite-type zeolite at a temperature of 400 to 600 ° C. for 2 to 4 hours; c) The calcined zeolite is treated with an aqueous solution of ammonium salt under the condition of pH 2.5 to 4.5, and the alkali metal or alkaline earth metal remaining in the zeolite is ion-exchanged with ammonium to obtain the alkali metal or alkaline earth metal in the zeolite. (D) calcining this zeolite at a temperature of 400 to 750 ° C. for 2 to 4 hours. Method of modifying a site-type zeolite is disclosed.

Conventional catalytic cracking catalysts using the various zeolites described above can provide reasonable results, even if the raw oil is a heavy hydrocarbon oil, as long as the raw material is a hydrocarbon with a relatively small amount of metal contaminants. I have.

However, in the case of catalytic cracking of low-grade heavy hydrocarbon oil, a conventional catalyst for catalytic cracking using a zeolite is not necessarily sufficient even if it is thermally and relatively stable against metal contaminants. It does not have residual oil resolution and does not keep coke and gas production to a satisfactory level.

[Object of the invention]

An object of the present invention is to provide a modified Y-type zeolite having a specific pore distribution, and further used for catalytic cracking of hydrocarbons, especially heavy hydrocarbons such as hydrogenated atmospheric residual oil. Demonstrates high residual oil resolution, high gasoline yield, and LCO / HCO ratio (LCO is light cycle oil, HC
O means heavy cycle oil), and provides a modified Y-type zeolite characterized by low coke and gas generation, a method for producing the same, and a catalyst composition for catalytic cracking of hydrocarbons using the same. .

[Summary of the Invention]

The present inventors have found that the characteristic pore distribution of Y-type zeolite has a close relationship between the amount of coke and the amount of gas generated when catalytic cracking of low-grade heavy hydrocarbons containing metal contaminants and the like. They found something and completed the present invention.

That is, the modified Y-type zeolite according to the present invention has, in the pore distribution measured by the nitrogen gas adsorption method (BJH method), (A) a pore volume occupied by pores having a diameter of 600 mm or less (a)
Is 0.40 ml / g or more, and (B) the pore volume (b) occupied by pores with a diameter of 30 mm or less is
0.30 ml / g or more, (C) Pore volume occupied by pores with a diameter of 30 to 600 mm (c)
Is 0.10 ml / g or more, and (c) / (b) is in the range of 0.25 to 0.45.

The method of the invention for preparing a modified Y-type zeolite having the above characteristics, the ammonium containing sodium of 4.5 to 6 weight percent range as the Na ₂ O - sodium -Y zeolite was calcined in a steam atmosphere and then The zeolite is subjected to an acid treatment at a pH of 3.5 or less.

The catalyst composition for catalytic cracking of hydrocarbons according to the present invention is obtained by dispersing the modified Y-type zeolite obtained by the above-described method in a porous inorganic oxide matrix.

[Specific description of the invention]

Hereinafter, the modified Y-type zeolite of the present invention, a method for producing the same, and a catalytic catalytic cracking catalyst composition using the same will be specifically described.

The modified Y-type zeolite of the present invention has a SiO ₂ / Al ₂ O ₃ molar ratio,
In terms of unit cell constants, etc., it belongs to the category of ultra-stable Y-type zeolite (USY) obtained by hydrothermal treatment or acid treatment of NH ₄ Y-type zeolite. Is distinguished. That is, the modified Y-type zeolite of the present invention has a pore distribution described in the claims.

In the feature of the pore distribution of the modified Y-type zeolite of the present invention, the modified (A) has a pore volume (a) occupied by pores having a diameter of 600 ° or less having a pore volume smaller than 0.40 ml / g. Y-type zeolite has low crystallinity, and the aluminum desorbed from the crystal structure reduces the pore volume. Therefore, when used as a catalyst for catalytic cracking of hydrocarbons, the activity of the catalyst decreases, and coke and gas are reduced. Production volume tends to increase.

Further, since the pore volume (c) occupied by the (C) pores having a diameter of 30 to 600 ° (hereinafter referred to as secondary pores) is smaller than 0.10 ml / g, the modified Y-type zeolite was used as a catalytic cracking catalyst. In this case, the diffusion of hydrocarbons having a large molecular weight is poor, and the resolution of residual oil tends to be low.

The pore volume (b) occupied by the (B) pores having a diameter of 30 ° or less (hereinafter referred to as primary pores) is based mainly on the pores of a cage having a uniform diameter peculiar to zeolite.

In the modified Y-type zeolite according to the present invention, the ratio between the volume (b) of the primary pores and the volume (c) of the secondary pores is important for obtaining desired performance when used in a catalytic cracking catalyst. is there.

When the ratio (c) / (b) of the volume (b) of the primary pores and the volume (c) of the secondary pores is smaller than 0.25, the ratio of the secondary pores to the volume of the primary pores is reduced. , The residual oil resolution tends to be low, and if it is larger than 0.45, the amount of coke and gas generation tends to increase. Preferred values of (c) / (b) are in the range of 0.30 to 0.40.

The pore distribution in the present invention was determined by sintering the sample at 600 ° C. for 1 hour in the air, followed by the BJH method using nitrogen gas adsorption.

The modified Y-type zeolite of the present invention has a SiO ₂ / Al ₂ O ₃ molar ratio of
5.5 or more, preferably 6.0 or more, the unit cell constant is 24.65
Å, preferably in the range of 24.30 to 24.60Å.

The modified Y-type zeolite, for example, (i) ammonium sodium content is in the range of 4.5 to 6% by weight Na ₂ O - Sodium -Y (NH _4-Na-
Y) type zeolite having a unit cell constant of about 24.30 to about 24.65.
(B) acid-treating the steam-treated zeolite at a pH of 3.5 or less to a sodium content of 2% by weight or less as Na ₂ O, It is manufactured by the following steps:

The NH ₄ —Na—Y type zeolite in the range of 4.5 to 6% by weight, preferably 4.5 to 5.5% by weight as Na ₂ O in the above (a) is obtained by ammonium ion exchange without calcining NaY obtained by synthesis. Obtained by

Steaming the NH ₄ -Na-Y-type zeolite, 500-85
It can be performed by rotating and firing in a steam atmosphere at a temperature of 0 ° C. for 1 to 6 hours. Ammonium-Y in which the Na ₂ O weight% of the NH ₄ —Na—Y type zeolite is less than 4%
When the zeolite is subjected to steam treatment, the ratio of the secondary pore volume tends to be too large. On the other hand, Na ₂ O weight% is 6%
If more NH ₄ —Na—Y type zeolite is subjected to steam treatment, the unit cell constant is less likely to decrease, and the crystallinity tends to decrease.

Further, calcining the NH ₄ —Na—Y type zeolite in a steam atmosphere is a weight in removing aluminum from the zeolite crystal structure without destroying the crystal structure. If it is calcined in air, the zeolite of the present invention cannot be obtained (see Comparative Example 1).

In the above (b), by treating the steam-treated zeolite at a pH of 3.5 or less, the sodium content is reduced to 2% or less, and aluminum desorbed from the crystal structure is removed. The acid treatment pH is preferably in the range of 2.5 to 3.5, and when the pH is lower than 2.5, the crystal structure may be broken, which is not desirable. If the pH is higher than 3.5, aluminum desorbed from the crystal structure cannot be removed to a desired amount.

A zeolite from which the aluminum desorbed from the crystal structure has not been sufficiently removed is not desirable because when used in a catalytic cracking catalyst composition, the amount of generated coke, hydrogen and the like tends to increase. This acid treatment can be performed in the presence or absence of ammonium ions, and as the acid treatment agent, a mineral acid such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, or an organic acid can be used.

The catalyst composition for catalytic cracking of hydrocarbons according to the present invention comprises the above-mentioned modified Y-type zeolite dispersed in a porous inorganic oxide matrix. As the porous inorganic oxide matrix, a porous inorganic oxide matrix usually used for a catalytic cracking catalyst such as silica, alumina, silica-alumina, and silica-magnesia can be used. Incidentally, the porous inorganic oxide matrix is a viscous mineral such as kaolin,
Metal scavengers such as alumina, calcium aluminate and magnesium silicate may also be included.

The above and modified Y in the catalytic cracking catalyst composition of the present invention.
The type zeolite is desirably in the range of 5 to 40% by weight as in the case of a usual catalyst for catalytic cracking. The catalytic cracking catalyst composition is produced, for example, by mixing a precursor of a porous inorganic oxide matrix with the above-described modified Y-type zeolite at a predetermined ratio, followed by spray drying, and washing and drying the resulting fine particles. Is done. In the above production method, it is possible to introduce phosphorus, rare earth or the like into fine particles obtained by spray drying, or to ion-exchange with rare earth metal or the like by a method known as the above-mentioned modified Y-type zeolite. You can also use what you have done. The catalyst precursor composition obtained by the spray drying described above is usually calcined in a hydrocarbon catalytic cracking device,
It changes to the desired catalyst composition. That is, a catalyst composition containing the modified Y-type zeolite having the pore distribution according to claim 1 in the matrix is obtained by this calcination.

Since the catalytic cracking catalyst composition of the present invention thus obtained is made of a modified Y-type zeolite having a specific pore distribution, when used for catalytic cracking of hydrocarbons, particularly heavy hydrocarbons, Low coke and gas production despite having high stability to metal contaminants and high residual oil resolution.

 Examples will be described below.

〔Example〕

Reference Example Production of Raw Material NaY A reaction mixture having the following molar composition was prepared using water glass, silica gel, sodium aluminate, sodium hydroxide and water.

2.7Na ₂ O: Al ₂ O ₃ : 8SiO ₂ : 120H ₂ O The reaction mixture was held at a temperature of 95 ° C. for 48 hours, filtered, and the resulting cake was dried at 110 ° C. for 16 hours to obtain NaY ( Sodium-Y type faujasite) was produced. Then, from the X-ray diffraction method and the chemical analysis, this Na-
Y has a crystallinity of 110% and a unit cell size of 24.70Å
It was confirmed that the molar ratio of SiO ₂ / Al ₂ O ₃ was 4.8.

The degree of crystallinity was determined by determining the total peak area S of the (533) and (642) planes of the X-ray diffraction diagram, and the total crystal area was determined using a commercially available sodium-Y type zeolite (manufactured by Union Carbide, SK-40). The peak area S ₀ was determined from the following equation with the crystallinity being 100%.

Crystallinity = 100 S / S ₀ Example-1 In this example, a method for preparing a modified Y-type zeolite using NaY (sample Y) produced in the reference example will be described.

A non-calcined sample Y1 kg was brought into contact with a 0.38 mol / aqueous ammonium sulfate solution 10 at a temperature of 90 ° C., washed, and washed with NH ₄ —Na—Y zeolite in which a part of sodium ions of NaY was ammonium ion exchanged ( 5.9wt containing Na ₂ O
%) Was prepared.

Next, the NH ₄ —Na—Y type zeolite was calcined at 650 ° C. for 3 hours in a steam atmosphere, and then the zeolite was heated to a temperature of 60 ° C.
And suspended in 1.64 mol / aqueous ammonium sulfate solution 5 held in water.
The pH was adjusted to 3.5 (60 ° C.) and the mixture was heated, acid-treated at a temperature of 90 ° C. for 1 hour, then washed and dried to prepare a modified Y-type zeolite (sample b).

 Table 1 shows the properties of the modified Y-type zeolite.

In the same manner as described above, the amount of the ammonium sulfate aqueous solution and the number of times of ion exchange were changed to prepare NH ₄ —Na—Y zeolites having different Na ₂ O amounts shown in Table 1, and then Table 1
Steam treatment was performed under the calcination conditions shown below, and then acid treatment was performed with only an aqueous solution of ammonium sulfate and an aqueous solution of sulfuric acid or sulfuric acid to prepare modified Y-type zeolite (samples, a, c, b, e, f, g, h). .

 Table 1 shows the properties of these modified zeolites.

Comparative Example 1 An NH ₄ —Na—Y type zeolite (5.9 wt% containing Na ₂ O) prepared in the same manner as in Example 1 was calcined at 650 ° C. for 3 hours in the air. The zeolite (sample i) was prepared by treating under the acid treatment conditions shown in Table 1.

 Table 1 shows the properties of this zeolite.

Comparative Example 2 Sample Y which had not been calcined was brought into contact with an aqueous solution of ammonium sulfate to carry out the first ion exchange to prepare an NH ₄ —Na—Y type zeolite (5.9 wt% containing Na ₂ O). This NH _{4 is} then used to increase the ion exchange rate and reduce the Na ₂ O content.
-Na-Y type zeolite was calcined in air at 630 ° C. for 3 hours, and then subjected to a second ion exchange using an ammonium sulfate aqueous solution to obtain NH ₄ —Na-Y type having a Na ₂ O content of 1.60 wt%. A zeolite was prepared.

The NH ₄ —Na—Y type zeolite was divided into three parts, each of which was subjected to steam treatment under the calcination conditions shown in Table 1 in the same manner as in Example 1, and further subjected to acid treatment with an aqueous ammonium sulfate solution and an aqueous sulfuric acid solution or an aqueous sulfuric acid solution alone. The zeolite (sample j, k, l) was prepared by the treatment. Comparative Example 2 shows a case where zeolite having a lower Na ₂ O content than that of the present invention was calcined in steam and subjected to an acid treatment.

 Table 1 shows the properties of these zeolites.

(Preparation of catalytic cracking catalyst composition.) Example 2 was prepared SiO ₂ concentration 12.73% water glass solution by diluting commercially available 3 Gosui glass. Separately, a 25% concentrated sulfuric acid was prepared. This aqueous glass solution and sulfuric acid are each 20 / min.
A silica hydrosol (bound) was prepared by continuously mixing at a rate of 5.6 / min for 10 minutes. An appropriate amount of the silica hydrosol thus prepared and an appropriate amount of a hydrogel of pseudoboehmite alumina obtained by a neutralization reaction of an appropriate amount of an aqueous solution of kaolin and sodium aluminate with an aqueous solution of aluminum sulfate (the amount of the catalyst used is The composition is such that the composition of the product will be the ratio described below), and then the above-prepared Example-1 and Samples b, e, f, h and Comparative Example-1,
After mixing the zeolites of each of the two samples i, j, k,
Spray dried. Wash the obtained dried particles,
Then, after being immersed in an aqueous solution of rare earth chloride, washed, dried and each of the catalytic cracking catalyst compositions B, E, F, H and I,
J and K were prepared. 35% by weight of each catalyst composition
It consisted of zeolite, 10% by weight pseudo-boehmite alumina, 35% by weight kaolin and 20% by weight of silica as binder, and contained 0.9% by weight of rare earth as RE ₂ O ₃ .

Example 3 (Evaluation of Catalyst Composition) Each of the catalysts B, E, F, H and I, J, and K prepared in Example 2 was calcined in air at 600 ° C. for 2 hours. Each catalyst was impregnated with a benzene solution containing nickel acid and vanadium naphthenate, and then benzene was removed under reduced pressure.
m and 3300 ppm of vanadium were deposited. The decomposition characteristics of each catalyst obtained in this way were converted to a conversion ratio of 55 to 66 wt% by using a hydrogenated atmospheric residual oil (DSAR) as a feedstock and changing the catalyst / oil ratio for comparison. A catalytic cracking test was performed with adjustment.

Prior to the test, each catalyst was calcined at 600 ° C. for 2 hours, then pretreated by contacting with 100% steam at 770 ° C. for 6 hours before the test. The evaluation results are shown in Table 2 and FIG.

[Effect] FIG. 1 is a plot of the amount of each product with respect to the conversion from the evaluation results in Table-2.

As can be seen from Table 1, the modified zeolite of the present invention has:
It can be seen that the pore volume is large and the ratio between the primary pore volume and the secondary pore volume is within a certain range.

When the catalytic composition for catalytic cracking of hydrocarbons prepared using such a modified zeolite is used for catalytic cracking of atmospheric residue (DSAR), as shown in Table 2 and FIG. Gasoline yield, LCO / HCO ratio, and low coke and hydrogen production when compared with other reference catalysts under low conversion. Such high residual oil resolution (high LCO / HC
Despite exhibiting O), the characteristic of low generation of coke and hydrogen is based on the characteristics of the modified Y-type zeolite.

[Brief description of the drawings]

FIG. 1 shows the evaluation results in Example 3, and is a diagram showing the relationship between the conversion and the amount of various products.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C01B 39/00-39/54 B01J 29/10

Claims (3)

(57) [Claims] (1) In a pore distribution measured by a nitrogen gas adsorption method (BJH method), (A) a pore volume occupied by pores having a diameter of 600 mm or less (a) is 0.40 ml / g or more, and (B) a diameter of 30 mm. (B) the pore volume occupied by the following pores is 0.30 ml / g or more, (C) the pore volume occupied by pores having a diameter of 30 to 600 mm is (c) 0.10 ml / g or more, and (c) ) / (B) is in the range of 0.25 to 0.45. 2. An ammonium-sodium-Y type zeolite containing sodium in the range of 4.5 to 6% by weight as Na ₂ O is calcined in a steam atmosphere, and then the zeolite is subjected to pH adjustment.
The method for producing a modified Y-type zeolite according to claim 1, wherein the acid treatment is performed at 3.5 or less. 3. An ammonium-sodium-Y type zeolite containing sodium in the range of 4.5 to 6% by weight as Na ₂ O is calcined in a steam atmosphere, and then the zeolite is brought to pH 3.
A catalyst composition for catalytic cracking of hydrocarbons, wherein a modified Y-type zeolite obtained by acid treatment at 5 or less is dispersed in a porous inorganic oxide matrix.