JPH0533102B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a catalyst composition for catalytic cracking of hydrocarbons, and more particularly, it relates to a catalyst composition for catalytic cracking of hydrocarbons, and more specifically,
Used in the catalytic cracking of heavy hydrocarbon oils containing large amounts of heavy metals such as nickel, iron, and copper, it exhibits excellent metal resistance, maintains high cracking activity and high gasoline selectivity for a long period of time, and The present invention relates to a catalyst composition that can suppress the production of hydrogen and coke to a low level, and a method for producing the same. [Prior art] Catalytic cracking of hydrocarbons is originally intended for the production of gasoline, so the catalyst used for this must naturally have high cracking activity and high gasoline selectivity. Therefore, metal resistance is required for catalysts for catalytic cracking. The worsening oil situation in recent years has forced the use of low-grade heavy hydrocarbon oil, typically residual oil containing heavy metals such as vanadium, nickel, iron, and copper, as a raw material for catalytic cracking. This makes the metal resistance of catalytic cracking catalysts increasingly important. Generally, during catalytic cracking of heavy hydrocarbon oil,
Due to the deposition of metal contaminants contained in the feed oil on the catalyst, the cracking activity and gasoline selectivity of the catalyst are reduced to a greater or lesser extent. Therefore, the catalysts for catalytic cracking currently in common commercial use, typically catalysts for catalytic cracking in which zeolite is dispersed in a porous inorganic oxide matrix, are somewhat satisfactory even if a certain amount of metal is deposited. Usually, it has enough metal resistance to maintain the desired catalytic performance.
However, when this type of catalyst is used to catalytically crack low-grade heavy hydrocarbon oils such as those mentioned above, the catalyst is also contaminated with a large amount of metal contaminants. is deposited, which promotes the dehydrogenation reaction, increasing the production of hydrogen and coke, and even destroying the crystal structure of the zeolite, making it impossible to fulfill the original purpose of catalytic cracking. Under these circumstances, as a countermeasure when subjecting low-grade heavy hydrocarbon oil with a large amount of metal contaminants to catalytic cracking, the amount of catalyst used is increased to reduce the amount of deposited metal per catalyst particle. Alternatively, measures have been taken to suppress the decrease in catalyst activity caused by deposited metals by adding an antimony compound to the raw oil. However, these operational countermeasures are not practical due to the increased operating costs.
On the other hand, as a measure to improve the performance of the catalyst, it is known that the amount of zeolite dispersed in the catalyst is increased compared to that of a normal catalytic cracking catalyst. A catalytic decomposition catalyst is described in which the catalyst contains a phosphorus compound to improve the metal resistance of the catalyst. Furthermore, US Pat. No. 4,228,036 discloses a catalytic decomposition catalyst in which zeolite is dispersed in an alumina-aluminum phosphate-silica matrix. [Problems to be solved by the invention] Among the conventional catalysts for catalytic decomposition developed to improve the metal resistance of the catalyst, the catalyst with increased zeolite content has the disadvantage that the zeolite itself is expensive. Therefore, it cannot be made into a commercially attractive catalyst. In addition, the phosphorus-containing catalyst as shown in the above two US patents can be used in Example 2 below.
As can be seen from (example of catalyst use), metal resistance is not necessarily sufficient. It is true that the phosphorus component contributes to improving the metal resistance of catalytic cracking catalysts, but conventional phosphorus-containing catalytic cracking catalysts contain too much metal because the phosphorus component is uniformly dispersed throughout the catalyst. It is presumed that if the metal is deposited, the metal resistance of the catalyst deteriorates, and only the results shown in Example 2 can be obtained. In addition, when an alumina-containing catalytic cracking catalyst is used for catalytic cracking of hydrocarbon oil to deposit vanadium, and the spent catalyst is analyzed with an X-ray microanalyzer, the distribution of deposited vanadium corresponds well to the distribution of alumina. The present inventors have discovered that. This fact suggests that by having alumina present in the form of a block within the catalyst for catalytic cracking, metal contaminants can be deposited intensively on the alumina block. [Means for Solving the Problems] The present invention provides a catalyst composition for catalytic cracking of hydrocarbons in which phosphorus-containing alumina particles with a particle size of 2 to 60μ and crystalline aluminasilicate zeolite are uniformly dispersed in a porous inorganic oxide matrix. I will provide a. In this catalyst composition, the phosphorus-containing alumina particles range from 5 to 75% by weight, and the crystalline aluminosilicate ranges from 5 to 75% by weight.
In the range of 50% by weight, the porous inorganic oxide matrix can be adjusted in the range of 20-50% by weight, respectively. The contact composition of the present invention can be prepared by spray drying a slurry of a mixture of phosphorus-containing alumina particles, crystalline aluminosilicate, and matrix precursor; The particle size must be in the range of 2 to 60 microns. If fine phosphorus-containing alumina particles with a particle size below this range are used, the alumina particles will be uniformly dispersed in the catalyst composition and cannot be unevenly distributed in the form of blocks. Moreover, it is not preferable for the particle size to exceed the above range in relation to the average particle size of the catalyst composition finally obtained. The particle size of the phosphorus-containing alumina particles is preferably in the range of 10 to 60 microns, more preferably in the range of 15 to 60 microns. Therefore, the phosphorus-containing alumina particles of the present invention can be produced by, for example, contacting alumina or alumina hydrate with a particle size of 2 to 60μ prepared in advance with an aqueous solution containing phosphate ions (PO ₄ ^3- ), or changing the particle size. Coarse alumina or alumina hydrate is brought into contact with an aqueous solution containing phosphate ions and dried, and after firing, this is reduced to a particle size of 2~
Manufactured by grinding to 60μ. The firing temperature is generally preferably in the range of 250 to 850°C. In any case, each aqueous solution of phosphoric acid, ammonium hydrogen phosphate, ammonium phosphate, phosphate ester, or a mixture thereof can be used as the phosphate ion-containing aqueous solution. The amount of phosphorus introduced into the alumina particles by contact with the aqueous solution containing phosphate ions can be in the range of 0.01 to 0.20 in terms of P/Al atomic ratio. This is because if the content is below this range, the effect of containing phosphorus will not be achieved, and if it is above this range, the pore volume of the alumina will decrease too much, which is not preferable. Calcining after introducing phosphorus is preferable because phosphorus is strongly fixed to alumina. Synthetic Y-type zeolite, mordenite, ZSM-type zeolite, natural zeolite, etc. can be used as the crystalline aluminosilicate of the present invention, and these can contain hydrogen, ammonium, and polyvalent zeolites, as in the case of ordinary catalysts for catalytic cracking. It is used in an ion-exchanged form with a cation selected from metals.
As the porous inorganic oxide, silica, silica-alumina, silica-magnesia, etc. can be used, and matrix components commonly used in ordinary catalysts for catalytic cracking can also be used in the present invention. The catalyst composition of the present invention can be produced in the same manner as in the production of a crystalline aluminosilicate zeolite/containing catalyst for catalytic cracking, except that phosphorus-containing alumina particles with a particle size of 2 to 60 μm are used. . That is, the catalyst composition of the present invention comprises a porous inorganic oxide matrix precursor slurry, such as silica hydrosol, silica-alumina hydrosol, etc., containing phosphorus-containing alumina particles with a particle size of 2 to 60 μm and crystalline aluminosilicate. It can be prepared by adding zeolite and uniformly dispersing it, and spray-drying the resulting mixture slurry in a conventional manner. and a matrix precursor slurry;
The amount of phosphorus-containing alumina particles and crystalline aluminosilicate zeolite used is such that the final catalyst composition contains 5 to 75 phosphorus-containing alumina particles.
Crystalline aluminosilicate zeolite in the range of 5 to 50% by weight in the matrix.
The content is adjusted to be within the range of 20 to 50% by weight. Then, the spray-dried particles are washed as necessary, and after washing, they are dried again. [Function] In the catalytic cracking reaction of hydrocarbon oil, metal contaminants such as vanadium and nickel contained in the feedstock oil are deposited on the catalyst, reducing the cracking activity and gasoline selectivity of the catalyst. The dehydrogenation reaction significantly increases the amount of coke and hydrogen produced. In particular, vanadium moves near the crystalline aluminosilicate zeolite in a catalyst regeneration atmosphere where the temperature is normally maintained at 630° C. or higher and destroys its crystal structure. In the catalyst composition for catalytic cracking of the present invention, phosphorus-containing alumina particles are dispersed in the composition in the form of particles with a particle size of 2 to 60μ, so metal contaminants deposited on the catalyst are captured by the particles. It aggregates and does not disperse in the composition. Therefore, even in the catalyst regeneration atmosphere, the movement of deposited metals, especially vanadium, to/near the crystalline aluminosilicate zeolite is suppressed, and the destruction of its crystal structure is also suppressed. It is also presumed that the phosphorus introduced into the alumina promotes the aggregation of metals such as vanadium and nickel captured on the alumina, and promotes the inactivation of these metals. Example 1 Aluminum hydroxide obtained by the Bayer method was calcined in air at 600°C for 2 hours. Next, 500 g of this calcined alumina was weighed out, and an aqueous phosphoric acid solution prepared by diluting 82 g of orthophosphoric acid with a concentration of 85% with water to make 115 ml was added to the calcined alumina and blended for 10 minutes. The phosphoric acid-added alumina particles were dried at 110°C for 17 hours and then calcined at 600°C for 1 hour to prepare phosphorus-containing alumina particles. The average particle size of these phosphorus-containing alumina particles is 30μ, and the phosphorus content is 4.2% by weight.
(The atomic ratio of P/Al was 0.07), and the specific surface area was 67 m ² /g. 5% by weight prepared by adding sulfuric acid to water glass
500 g of the phosphorus-containing alumina particles described above were added to 4000 g of silica hydrosol containing SiO ₂ and 300 g of hydrogen ion-exchanged Y-type crystalline aluminosilicate (zeolite) was added to obtain a mixed slurry. This mixed slurry was then spray-dried, washed, and further dried to obtain the catalyst composition for catalytic cracking of the present invention. This catalyst composition contained 50% by weight of phosphorus-containing alumina particles, 30% by weight of H-Y type zeolite, and 20% by weight of silica derived from the matrix, and had an average particle size of 68 microns. This catalyst composition was used as catalyst A.
shall be. Comparative Example 1 This example relates to the conventional catalyst described in US Pat. No. 4,228,036. The aluminum sulfate solution was neutralized with aqueous ammonia, and the formed aluminum hydroxide precipitate was washed to remove by-product salts. To this alumina hydrogel slurry corresponding to an amount of 450 _g as _AL2O3 , 85
Phosphorus content of alumina is 4.2% orthophosphoric acid
The mixture was added with stirring to obtain a phosphorus-containing alumina hydrogel slurry. SiO ₂ concentration 5wt prepared by adding sulfuric acid to water glass
A mixed slurry was prepared by adding 6250 g of the above phosphorous-containing alumina hydrogel slurry to 4000 g of silica hydrosol, and further adding 300 g of H-Y type zeolite. Next, this slurry was spray dried in the same manner as in Example 1, washed, and further dried to obtain a catalyst composition for catalytic cracking. This catalyst composition has a total amount of phosphorus and alumina.
It contained 49.6% by weight, 30% by weight of H-Y type zeolite, and 20.4% by weight of silica derived from the matrix. This will be referred to as catalyst B. Comparative Example 2 This example shows a conventional catalyst corresponding to US Pat. No. 4,430,199. Commercially available No. 3 water glass was diluted to prepare a water glass solution with a SiO ₂ concentration of 11.2%. Separately, an aluminum sulfate solution with a concentration of 10.5% was prepared. This water glass solution and aluminum sulfate solution were mixed while being poured into a container at a rate of 20/min and 10/min, respectively.
A silica-alumina hydrogel slurry was prepared. After aging the slurry at 65℃ for 3.5 hours,
A water glass solution was added to this to adjust the pH to 5.8 and stabilize it. After that, add H-Y to this slurry.
type zeolite is mixed so that the zeolite content of the final catalyst composition is 30% by weight, and the resulting mixed slurry is spray-dried in the same manner as in Example 1, washed and dried to obtain a phosphorus-free catalyst composition. I got it. Next, this catalyst was calcined at 600℃ for 1 hour, and the concentration of 22
% orthophosphoric acid aqueous solution and then dried to obtain a phosphorus-containing catalyst composition. This catalyst contains 2.1% by weight of phosphorus, 30% by weight of H-Y zeolite, and 67.9% by weight of silica-alumina.
It contained. This catalyst will be referred to as catalyst C. Example 2 (Example of Catalyst Usage) Each of the above catalysts A to C was evaluated for performance using ASTM MAT. First, in order to examine metal resistance, nickel and vanadium were deposited on each catalyst as follows. That is, each catalyst was preliminarily calcined at 600°C for 1 hour, and then a predetermined amount of a benzene solution of nickel naphthenate and vanadium naphthenate was absorbed into each catalyst, then dried at 110°C, and then calcined at 600°C for 1.5 hours. After that, to achieve pseudo-equilibrium, each catalyst was
It was steam-treated at 770°C for 6 hours and fired again at 600°C for 1 hour. Further, each catalyst on which nickel and vanadium were not deposited was also subjected to steam treatment at 770°C for 6 hours for pseudo-equilibrium, and then calcined at 600°C for 1 hour. Using each of the catalysts pretreated in this way, an ASTM MAT evaluation test was conducted. Display the results -
Shown in 1. Incidentally, the reaction conditions are as follows. Feedstock oil: Desulfurized vacuum gas oil Reaction temperature: 482℃ Space velocity: 16hr ^-1 Catalyst/oil ratio: 3 (weight)

【table】

[Table] As shown in Table 1, Catalyst A, which corresponds to the catalyst composition of the present invention, maintains high cracking activity and high gasoline selectivity even when a large amount of metal is deposited, and also has high cracking activity. Nevertheless, the production rate of coke and hydrogen can be kept to a low level. In contrast, the cracking activity and gasoline selectivity of Catalyst B of Comparative Example 1 and Catalyst C of Comparative Example 2 are significantly reduced due to the deposition of a large amount of metal. Next, for catalysts A and B on which metals have been deposited, the distribution of Al, Si, and V in the catalyst particles is
It was investigated using a line microanalyzer (XMA). The measurement was carried out in accordance with the method described in Journal of Japan Petroleum Institute, Vol. 26, p. 344 (1983). The results are shown in FIG. 1 (catalyst A) and FIG. 2 (catalyst B). As is clear from the comparison between Figures 1 and 2, catalyst A has alumina dispersed in the catalyst particles.
In this case, Al and V show almost the same distribution, which indicates that V is selectively deposited on alumina. On the other hand, in catalyst B, it can be seen that V is uniformly deposited in the catalyst particles. Example 3 Aluminum hydroxide with an average particle size of 50μ obtained by the Bayer method was treated with phosphoric acid in the same manner as in Example 1, and the phosphorus content was 0.008, 0.14, and 0.22 in the atomic ratio of P/Al.
Phosphorus-containing alumina particles were prepared. Using these phosphorus-containing alumina particles, 50% by weight of the phosphorus-containing alumina particles and H
-30% by weight of Y-type zeolite, 20% by weight of silica
Containing catalysts D, E and F were obtained. Next, predetermined amounts of nickel and vanadium were deposited on each of these catalysts in the same manner as in Example 2 to achieve pseudo-equilibrium, and the metal resistance of each catalyst was evaluated under the same conditions as in Example 2. The results are shown in Table-2. Catalysts D and F, in which the P/Al atomic ratio of the phosphorus-containing alumina is outside the range of 0.01 to 0.20, have lower gasoline ratios and more coke than E.

[Table] [Effects] The hydrocarbon catalytic cracking catalyst composition of the present invention exhibits high cracking activity and high gasoline selectivity even when a large amount of metal contaminants are deposited on the catalyst, and suppresses the production of coke and hydrogen. quantity can be kept to a low level.

[Brief explanation of the drawing]

FIGS. 1 and 2 are drawings showing the distribution states of Si, Al, and V in catalyst A of the present invention and comparative catalyst B, respectively.

Claims (1)

[Scope of Claims] 1. A catalyst composition for catalytic cracking of hydrocarbons, in which phosphorus-containing alumina particles with a particle size of 2 to 60 μm and crystalline aluminosilicate zeolite are uniformly dispersed in a porous inorganic oxide matrix. 2. The composition according to claim 1, which contains 5 to 75% by weight of phosphorus-containing alumina particles, 5 to 50% by weight of crystalline aluminosilicate zeolite, and 20 to 50% by weight of porous inorganic oxide matrix. Catalyst composition. 3. The catalyst composition according to claim 1, wherein the phosphorus-containing alumina particles have an atomic ratio of P/Al in the range of 0.01 to 0.20. 4 For hydrocarbon catalytic cracking, which consists of mixing phosphorus-containing alumina particles with a particle size of 2 to 60 μm and crystalline aluminosilicate zeolite in a porous inorganic oxide precursor slurry, and spray drying the resulting mixed slurry. Method for producing catalyst composition. 5. The method according to claim 4, which uses phosphorus-containing alumina particles having an atomic ratio of P/Al in the range of 0.01 to 0.20.