JP7009770B2 - Method for producing zeolite molded product and lower olefin - Google Patents

Description

The present invention relates to a zeolite molded body for producing a lower olefin used as a catalyst for a fluidized bed reaction, and a method for producing propylene from a lower hydrocarbon such as ethylene as a raw material.

In a fluidized bed reaction, a reaction gas is usually supplied from the lower part of a reactor filled with a catalyst, the catalyst particles flow in the reactor by the gas flow, and the reaction occurs when the catalyst particles and the reaction gas come into contact with each other. proceed. Here, the catalyst used in the fluidized bed reaction has not only chemical performance but also physical properties suitable for the fluidized bed reaction such as particle shape, size, distribution, fluidity, and strength. Is required.
In the flow layer reaction process, when the catalyst particles are worn or crushed due to collision or contact between the catalyst particles, between the catalyst particles and the reactor, or between the catalyst particles and the reaction gas, the fluidity of the catalyst particles is reduced. Since the crushed particles are scattered, the fluid layer reaction catalyst is required to have sufficient mechanical strength to withstand wear and crushing.

That is, the catalyst used for the fluidized layer reaction needs to have mechanical strength (wear resistance) capable of withstanding collision and contact between the catalyst particles, the catalyst particles and the reactor, and the catalyst particles and the reaction gas. .. In order to impart such characteristics, a method is known in which a catalytically active component such as a metal, a composite oxide, or a zeolite is molded together with a carrier component such as silica or a binder, and the molded body is calcined. For example, Patent Document 1 describes a silica molded product containing zeolite, silica and phosphorus in a specific ratio as a catalyst for producing propylene. Patent Document 2 describes a zeolite-containing catalyst composed of a zeolite, an aluminum phosphate-containing binder, and a matrix. Further, Patent Document 3 describes a silylated zeolite as a catalyst for producing propylene. Further, Patent Document 4 describes that phosphorus, boron, and silica sol are added to a silylated zeolite to form a zeolite molded product.

Japanese Unexamined Patent Publication No. 2009-22130 Japanese Unexamined Patent Publication No. 4-354541 Japanese Unexamined Patent Publication No. 2013-75276 Japanese Unexamined Patent Publication No. 2016-175038

However, in these previously known techniques, for example, Patent Document 1 and Patent Document 3, only molded bodies having low collision durability are obtained, and in Patent Document 2, zeolite (ZSM-5) / silica slurry is used. There is a problem that only a soft catalyst having low wear resistance can be obtained from the aluminum phosphate binder. Further, all of Patent Documents 1 to 3 have a problem that the selectivity of propylene cannot be maintained at a high level for a long period of several tens of hours from the initial stage of the reaction in the production of propylene. Further, in the case of the zeolite molded product described in Patent Document 4, while the wear resistance is improved, the selectivity of propylene is not sufficient, and the selectivity of propylene may decrease with the passage of time. It has been found.
In view of the above situation, the present invention presents a zeolite molded body as a catalyst for a fluidized bed reaction, which has excellent collision durability, improved selectivity in the production of propylene, and the selectivity is stably maintained for a long period of time, and the production thereof. The purpose is to provide a method.

As a result of diligent research to solve the above problems, the present inventors have made it possible to use a zeolite molded body containing 8-membered ring-structured zeolite and alumina as a catalyst for the fluidized bed reaction in propylene production. We have found that it has fluidity, impact durability, selectivity in propylene production, and stability, and have reached the present invention.

That is, the present invention is as follows.
[1] A zeolite molded body containing 8-membered ring-structured zeolite and alumina.
[2] The zeolite molded product according to [1], wherein the mass ratio of alumina to the mass of the 8-membered ring-structured zeolite is 10 or less.
[3] The proportion of the zeolite molded body that is crushed when the zeolite catalyst is made to collide with the metal plate by blowing air containing water equivalent to the vapor pressure at 5.0 L / 50 seconds for 2 hours is 3% by mass or less. The zeolite molded product according to [1] or [2], which is characterized by the above.
[4] The zeolite molded product according to any one of [1] to [3], wherein the 8-membered ring-structured zeolite is a CHA-type zeolite.
[5] The zeolite molded product according to any one of [1] to [4], wherein at least a part of the 8-membered ring-structured zeolite is silylated.
[6] The zeolite molded product according to any one of [1] to [5], wherein the 8-membered ring-structured zeolite is a zeolite having an average particle size of 0.1 to 50 μm.
[7] The zeolite molded product according to any one of [1] to [6], which has an angle of repose of 20 to 35 °.
[8] The zeolite molded product according to any one of [1] to [7], which has a bulk density of 0.5 to 1.3 g / cm ³ .
[9] A step of contacting the zeolite molded product according to any one of [1] to [8] with a hydrocarbon raw material containing at least one selected from the group consisting of ethylene, ethanol, methanol, and dimethyl ether. A method for producing a lower olefin, including.

The zeolite molded product of the present invention is a zeolite molded product having excellent collision durability and a high active density, and has suitable physical properties as a catalyst for a flow layer reaction. Therefore, ethylene is subjected to a flow layer reaction. By using it as a catalyst for producing propylene from a hydrocarbon raw material such as the above, propylene can be stably produced at a high conversion rate, in good yield, and over a long period of time.

Hereinafter, the present invention will be described in more detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.
In the present specification, alumina is a constituent element constituting a zeolite molded product together with zeolite.

[Zeolite molded body]
The zeolite molded product of the present invention contains 8-membered ring-structured zeolite (oxygen 8-membered ring-structured zeolite) and alumina.

In order to obtain a zeolite molded body, even if only zeolite is molded, the catalyst strength is insufficient, which is generally not realistic. Therefore, it is common to use a binder called a binder. In particular, a silica binder is generally used as a catalyst for the propylene production reaction. The reason for this is that the silica of the silica binder is an inert substance in the propylene production reaction and has almost no adverse effect on the reaction.
On the other hand, silica has a low polarity, a weak force for binding zeolite particles, and a tendency to weaken the catalytic strength of the obtained zeolite molded product. Therefore, as described in the known Patent Document 1 or Patent Document 4, it is necessary to add mineral acids such as phosphoric acid to increase the catalytic strength of the molded product. However, according to the study by the present inventors, the zeolite molded body to which phosphoric acid or the like is added, which is described in Patent Document 1 or Patent Document 4, has a high strength of the molded body but a low catalytic performance. It turned out that it may end up.

On the other hand, as the binder, in addition to the above-mentioned silica binder, for example, as described in US Pat. No. 4,456780 and Japanese Patent No. 5700376, medium pore size zeolite of about 0.55 nm such as MFI, or An example in which an alumina binder is used in a zeolite having a large pore diameter exceeding 0.7 nm such as FAU has also been reported. Alumina binder has high polarity and has a strong force to bind zeolite particles. Therefore, it tends to be easy to obtain a zeolite molded body having sufficient catalytic strength.
However, alumina in the alumina binder often exists as boehmite, and the aluminum element has an acid property. Therefore, these aluminum elements move to the aluminum sites in the zeolite skeleton and exhibit strong acid properties. Therefore, when propylene is produced using a zeolite molded product as a catalyst, the new acid properties generated by the movement of the aluminum element accelerate the coke formation and shorten the catalyst life, or reduce the propylene yield. It is believed that a side reaction that affects the disease occurs. Therefore, a zeolite molded product using an alumina binder for an intermediate pore diameter zeolite such as MFI having an intermediate pore diameter of about 0.55 nm or a large pore diameter zeolite having a pore diameter exceeding 0.7 nm such as FAU is steamed before being used in the propylene production reaction. It was necessary to suppress the acid properties of aluminum by performing pretreatment such as.

However, according to the studies by the present inventors, the steaming treatment is a treatment that causes considerable damage to the zeolite skeleton structure, and tends to reduce the catalytic performance of the obtained zeolite molded product, and further, has an acid property. It turned out that there is a problem that the cost for the suppression process is high. Therefore, in consideration of this problem, it is considered unfavorable to use an alumina binder as a binder in the zeolite molded product, but according to the studies by the present inventors, surprisingly, in the 8-membered ring structure zeolite, it is considered that it is not preferable. It has been found that even if an alumina binder is used as a binder, it is possible to provide a zeolite molded product in which deterioration of catalytic performance is suppressed without performing a steaming treatment. The reason for this is not clear, but it is considered to be derived from the pore size of the 8-membered ring-structured zeolite. That is, the pore diameter of the 8-membered ring-structured zeolite is about 0.38 nm, which is considerably smaller than the pore diameter of zeolite such as MFI or FAU. Therefore, the amount of aluminum element entering the zeolite skeleton from the alumina binder can be suppressed, and as a result, the catalyst performance is less deteriorated without performing additional suppression treatment of the acid property derived from the binder such as steaming treatment. It is considered that a zeolite molded product having a long catalyst life and sufficient catalyst strength can be provided.

In the zeolite molded body according to the present invention, the mass ratio of alumina (alumina / zeolite) to the mass of zeolite having an 8-membered ring structure is not particularly limited, but is 10 or less in order to maintain excellent collision durability. Is preferable, and it is more preferably 3 or less, and further preferably 1.5 or less. Further, it is more preferably larger than 0, preferably 0.2 or more, and more preferably 0.33 or more.

Further, the zeolite constituting the zeolite molded product according to the present invention is preferably aluminosilicate or siliconoaluminophosphate, as will be described later.

When the zeolite constituting the zeolite molded body is aluminosilicate, the Al ₂ O ₃ mass ratio of the entire zeolite molded body to SiO ₂ is not particularly limited, but is preferably 0.1 to 30, more preferably 0.1 to 30. It is 0.15 to 20, particularly preferably 0.2 to 15.

On the other hand, when the zeolite constituting the zeolite molded body is silicoaluminophosphate, the Al ₂ O ₃ mass ratio of the entire zeolite molded body to SiO ₂ is not particularly limited, but is preferably 1 to 300, and further. It is preferably 3 to 200, and particularly preferably 8 to 150. If the SiO ₂ / Al ₂ O ₃ mass ratio is too small, the selectivity in the production of propylene may decrease. If it is too large, the wear loss of the zeolite molded body tends to increase. The Al _{2 O 3 referred to here contains both Al 2 O 3 in the} zeolite and Al ₂ O ₃ in the alumina binder constituting the zeolite forming body, but constitutes a clay mineral added as an auxiliary agent. Al ₂ O ₃ shall not be included.
Here, the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite molded product can be obtained by dissolving the zeolite molded product in an alkaline aqueous solution and analyzing the obtained solution by plasma emission spectroscopic analysis.

As described above, the zeolite contained in the zeolite molded product according to the present invention is an 8-membered ring-structured zeolite (oxygen 8-membered ring-structured zeolite). This 8-membered ring-structured zeolite means a ring structure in which the pores of the zeolite are composed of 8 TO ₄ units (T is Si, P, Ge, Al, Ga, etc.). By adopting such a structure, it is considered that the pore diameter of zeolite is in the range where the propylene selectivity can be increased.

The skeletal structure of a zeolite whose pores are composed of an oxygen 8-membered ring as described above is represented by a code defined by the International Zeolites Association (IZA), for example, AEI, AFX, CAS, CHA, DDR, ERI. Examples thereof include ESV, GIS, GOO, ITE, JBW, KFI, LEV, LTA, MER, MON, MTF, PAU, PHI, RHO, RTE, RTH, and the like.

Of these, AEI, AFX, CHA, DDR, ERI, LEV, RHO and RTH are preferable, CHA or AEI and ERI are more preferable, and CHA structure is particularly preferable.

Examples of the zeolite having a CHA structure include aluminosilicates whose constituent elements are silicon and aluminum, aluminophosphates (ALPO) made of aluminum and phosphorus, and siliconaluminophosphates (SAPO) whose constituent elements are silicon, aluminum and phosphorus. Of these, aluminosilicate or aluminoaluminophosphate is preferable, and aluminosilicate is more preferable.

The diameter of the pores (channels) of the zeolite is generally indicated by the crystalline channel diameter (Crystalloghaphic free diamonds of the channels) defined by the International Zeolites Association (IZA), and the upper limit thereof is 0. It is 5.5 nm or less, more preferably 0.4 nm or less, and the lower limit is 0.2 nm or more, more preferably 0.3 nm or more.

When the pore diameter of zeolite exceeds 0.5 nm, by-products other than propylene (butene, pentene, etc.) increase, and the selectivity tends to decrease. On the other hand, if the pore diameter is less than 0.2 nm, neither ethylene nor propylene can pass through the pores, the frequency of contact between ethylene and the catalytic active site decreases, and the reaction rate tends to decrease.
By setting the pore diameter within the above range, side reactions can be suppressed and the selectivity of propylene can be increased.

The average particle size of the 8-membered ring-structured zeolite is preferably 0.05 μm to 50 μm, preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 20 μm, and 0.5 μm to 4 μm. Is more preferable.
If the average particle size of the zeolite is too large, the collision durability of the zeolite molded product tends to decrease. If the average particle size of the zeolite is too small, the crystallinity of the zeolite is lowered and the catalytic activity of the zeolite molded product tends to be lowered. The average particle size can be measured by a laser diffraction / scattering type particle size distribution meter. The average particle size referred to here is the particle size distribution of powdery zeolite (the ratio of particles within a certain particle size section) measured by the above analyzer, and the cumulative particle size distribution is calculated with the total volume as 100%. , That is, the particle size at the point where the cumulative total is 50%, that is, the cumulative average diameter (center diameter, Median diameter).

The 8-membered ring-structured zeolite contained in the zeolite molded product of the present invention may be an aggregated type or a non-aggregated type.

The 8-membered ring-structured zeolite contained in the zeolite molded product of the present invention is preferably a silylated zeolite, as will be described later. By forming a zeolite molded body containing a silylated 8-membered ring-structured zeolite, it becomes possible to act as a catalyst with further improved selectivity in the production of propylene.

When the zeolite molded product of the present invention is used as a catalyst, it is usually a proton exchange type, but some of them are long-periodic periodic table group 1 elements (excluding hydrogen) such as sodium and potassium, magnesium, and calcium. It may be exchanged for a group 2 element of the long-periodic table such as.

The zeolite used in the present invention can be prepared by a commonly used hydrothermal synthesis method. Further, a hydrothermal synthesis method in which the composition is changed by ion exchange, dealuminum treatment, impregnation, etc. can also be used.

The alumina binder contains at least one of aluminum oxides and hydroxides. Here, examples of at least one of aluminum oxides and hydroxides include powder alumina such as γ-alumina and boehmite, aluminum hydroxide and alumina sol. One of these may be used alone, or two or more thereof may be mixed and used.

The average particle size of alumina in the powdered alumina and the alumina sol is closely related to the wear resistance and bulk density of the zeolite molded product, and the average particle size in the slurry is particularly important. The smaller the average particle size in the slurry, the more uniform and dense the filled state of the zeolite particles and alumina, the better the wear resistance of the zeolite molded product, and the more appropriate the bulk density tends to be. The average particle size in the preferred slurry is 10 nm to 300 nm, more preferably 10 to 200 nm.

Further, the zeolite molded product according to the present invention may contain other auxiliaries in addition to the 8-membered ring-structured zeolite and alumina. For example, the zeolite molded product may contain clay minerals such as kaolin, silica, zirconia, titania, ceria and the like. These contents are preferably 70% by mass or less, more preferably 50% by mass, and particularly preferably 30% by mass or less with respect to the total mass of the molded body.

Further, the alumina molded product of the present invention may contain phosphorus and / or boron.
The total mass of phosphorus and boron with respect to the mass of the zeolite constituting the alumina molded product is not particularly limited, but is preferably 0% by mass to 7.5% by mass, and more preferably 0% by mass to 5.0% by mass. It is particularly preferably 0% by mass to 3.0% by mass. If the mass ratio is too large, the fluidity tends to decrease, and the activity of the catalyst and the life of the catalyst tend to decrease.
The mass ratio can be obtained by dissolving the zeolite molded product in an alkaline aqueous solution and quantitatively analyzing each of silicon, aluminum, phosphorus and boron by plasma emission spectroscopic analysis.

When the zeolite molded product contains phosphorus and boron, the mass of boron with respect to the total mass of phosphorus and boron in the zeolite molded product is preferably 30% by mass to 80% by mass, and more preferably 35% by mass to 75% by mass. It is by mass, particularly preferably 40% by mass to 75% by mass. If the mass ratio is too small, phosphorus tends to affect the reaction performance and the selectivity of propylene tends to decrease, and if it is too large, the shape of the zeolite molded product may deteriorate and the fluidity may decrease.

Further, the ratio of the zeolite molded body that is crushed when the zeolite catalyst is made to collide with the metal plate by blowing air containing water equivalent to the vapor pressure at 5.0 L / 50 seconds for 2 hours (hereinafter referred to as wear loss). ) Means that the smaller the value, the better the collision durability. In particular, when the wear loss of the zeolite molded body is 3% by mass or less, the zeolite molded body has extremely little wear and breakage, excellent collision durability, excellent mechanical strength, and little loss during the propylene production reaction. It can be suitably used as a catalyst for a fluidized bed. Above all, the wear loss of the zeolite molded product is more preferably 2.5% by mass or less.

The zeolite molded product of the present invention has an angle of repose of preferably 20 ° to 35 °, more preferably 22 ° to 34 °, still more preferably 24 ° to 33 °, and particularly preferably 25 ° to 25 °. It is 32 °. If the angle of repose is too small, the fluidity tends to be excessive, so that the handleability tends to deteriorate, and if it is too large, the fluidity tends to decrease and bridging between zeolite moldings tends to occur easily.

The bulk density is important as an index of the spheroidity or flow state of the zeolite molded product. The zeolite molded product of the present invention has a bulk density of preferably 0.50 g / cm ³ to 1.30 g / cm ³ , more preferably 0.53 g / cm ³ to 1.25 g / cm ³ , and particularly preferably 0. It is 55 g / cm ³ to 1.20 g / cm ³ . When a zeolite molded body having a bulk density within the above range is used as a catalyst in a fluidized bed reaction, the reaction gas linear velocity is improved, and the mass transfer and heat transfer between the catalyst particles and the reaction gas tend to be better. It is in. If the bulk density is too small, the proportion of distorted catalyst particles, cracks, chips, and hollow catalyst particles tends to increase, and if it is too large, the specific surface area decreases and the chemical performance as a catalyst is insufficient. It tends to be.

[Manufacturing method of zeolite molded body]
The zeolite molded product of the present invention is not particularly limited, but can be produced by (i) a step of preparing a raw material mixture and (ii) a step of drying.

[Step (i): Preparation step of raw material mixture]
In the raw material preparation step, zeolite having an 8-membered ring structure, which is a solid component as a raw material, and alumina powder or alumina sol are mixed in a liquid medium to produce a slurry in which the solid component is dispersed. The liquid medium is preferably water. In the case of producing a zeolite molded body containing auxiliary agents, the auxiliary agents may be added to the above-mentioned raw materials and dispersed or dissolved in a liquid medium to form a slurry. Similarly, when a zeolite molded product containing phosphorus and / or boron is produced in the zeolite molded product, a phosphorus compound and / or a boron compound is added to the above-mentioned raw materials and dispersed or mixed in a liquid medium. A slurry may be formed.

Hereinafter, the case where water is used as the liquid medium will be described as an example.
When alumina, which is a solid component, is an alumina powder, it is preferable to handle it as an alumina sol dispersed in water because of its good mixing property. The 8-membered ring-structured zeolite, which is a solid component, may be used as a powder or as a slurry dispersed / suspended in water or a part of an alumina sol. Further, when an auxiliary agent, a phosphorus compound, a boron compound or the like is added as a raw material, these may be used as they are or may be used after being dissolved and dispersed in water or the like in advance.

As the alumina powder or alumina sol, powdered alumina or alumina sol stabilized with acetic acid, hydrochloric acid, nitric acid or the like can be used. It is preferably acetic acid-stabilized powdered alumina or alumina sol. Further, powdered alumina or alumina sol can be used together with aluminosilicate, silica, titania, zirconia, ceria, kaolin, diatomaceous earth and the like, and these may be used in combination of two or more.

The auxiliaries are not particularly limited, but examples thereof include the auxiliaries listed above.

Phosphoric compounds include phosphoric acid, phosphoric acid, hypophosphoric acid, pyrophosphate, polyphosphoric acid, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, triammonium phosphate, ammonium perphosphate, and ammonium hypophosphite. , Phosphoric acid pentoxide, phosphins and the like can be used. A water-soluble phosphorus compound such as phosphoric acid, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, triammonium phosphate, pyrophosphoric acid, and polyphosphoric acid is preferable, and phosphoric acid is more preferable. These can be used alone, as a mixture, as an aqueous solution, or the like.

As the boron compound, boric acid, sodium tetraborate, sodium perborate, boron tribromide, diboron trioxide, boron trifluoride, boron phosphate, boron silicate, boron carbide, boron nitride and the like should be used. Can be done. A water-soluble boron compound such as boric acid, sodium tetraborate, sodium perborate, boron tribromide, boron tribromide, and boron trifluoride is preferable, and boric acid is more preferable. These can be used alone, as a mixture, as an aqueous solution, or the like.

The mixing order of the raw materials when preparing the raw material mixture of the zeolite molded product is not particularly limited. Zeolites may be added to the alumina sol, and phosphorus compounds and boron compounds may be added to the mixture, or phosphorus compounds and boron compounds are added to the powdered alumina slurry which has been well dispersed in water in advance, and zeolite is added to the mixture. May be. The 8-membered ring-structured zeolite is an 8-membered ring-structured zeolite powder, a slurry in which an 8-membered ring-structured zeolite is dispersed / suspended in water, or an 8-membered ring-structured zeolite dispersed / suspended in a part of an alumina sol. It is preferable to use it as a slurry. The phosphorus compound and the boron compound may be used as they are, or may be dispersed in water or the like in advance.

Further, an acid may be appropriately added to the raw material mixture in order to suitably adjust the pH of the raw material mixture. In this case, examples of the acid that can be used include sulfuric acid, hydrochloric acid, nitric acid and the like, and nitric acid is preferable. The pH of the raw material mixture is preferably 0.5 to 10, and more preferably 0.5 to 4. These raw materials are generally put into a tank-shaped container equipped with a stirrer and stirred and mixed to prepare a uniform slurry.

The solid content mass concentration of the raw material mixture is not particularly limited, but is preferably 5% by mass to 70% by mass, and more preferably 10% by mass to 50% by mass.
By setting the concentration in the above range, mixing and stirring can be performed appropriately, and the handleability of the slurry is improved.

The stirring time of the raw material mixture is preferably 0.5 hours to 50 hours, more preferably 1 hour to 5 hours. The temperature of the mixture during stirring is preferably 10 ° C. to 90 ° C., more preferably 15 ° C. to 70 ° C., and even more preferably 15 ° C. to 40 ° C. The viscosity of the raw material mixture may be increased by heating as needed.
Further, a surfactant that adjusts the surface tension of the raw material mixture may be added for the purpose of making the shape of the zeolite molded body more spherical.

[Step (ii): Drying step]
The drying step is a step of spray-drying the slurry produced in the preparation step of the raw material mixture to obtain a dry powder.
The slurry produced in the raw material preparation step can be spray-dried immediately after preparation, or after preparation, it is spray-dried after mixing and stirring for a predetermined time to control the amount of adsorbed auxiliary agent or the like on the 8-membered ring-structured zeolite. You may.
A method such as a rotary disk method, a two-fluid nozzle method or a high-pressure nozzle method can be adopted for spraying the slurry in the spray drying step, but it is preferable to use the rotary disk method or the two-fluid nozzle method.

As the drying heat source, it is preferable to use air heated by steam, an electric heater, or the like. The temperature of the drying airflow at the inlet of the dryer (hereinafter referred to as “inlet temperature”) is preferably more than 100 ° C. and 400 ° C. or lower. A more preferable inlet temperature is 150 ° C to 350 ° C.
The distribution method of the drying airflow may be a parallel flow method or a counterflow method, but the parallel flow method is preferable from the viewpoint of drying efficiency and prevention of adhesion to the inner wall of the dryer. ..

The temperature of the drying airflow at the outlet of the dryer (hereinafter referred to as "outlet temperature") is preferably more than 80 ° C. and 250 ° C. or lower, more preferably 85 ° C. to 200 ° C. As a matter of course, the inlet temperature is higher than the outlet temperature.
If the dryer inlet temperature or outlet temperature is lower than the above range, drying may be insufficient and deposits may be formed on the inner wall of the dryer, or irregular particles such as particles fused to each other may be formed. Alternatively, the strength of the obtained particles may be insufficient, and pulverization may become significant during use. On the other hand, if the inlet temperature or the outlet temperature of the dryer exceeds the above range, it is energetically disadvantageous.

The temperature difference (Δt) between the inlet temperature and the outlet temperature is preferably more than 50 ° C. and 300 ° C. or less, and a more preferable temperature difference is 60 ° C. to 250 ° C. If this temperature difference is 50 ° C or less, the drying efficiency is low and the equipment capacity cannot be fully utilized. On the other hand, if the temperature difference exceeds 300 ° C, the thermal history of the catalyst becomes excessive and the obtained catalyst is suitable for flow. There is a risk that it will not have a shape.

In order to perform good drying and obtain catalyst particles having a shape and strength suitable for use in a fluidized bed reactor, the mass ratio of the water content in the supplied slurry in the spray drying step to the drying airflow is 0.005 to 0. It is necessary to dry so that it becomes .2. If it is less than this range, a large amount of drying airflow will be required and the energy efficiency will decrease. May occur.

There is no particular limitation on the shape of the spray-drying device, but in general, a device with a cylindrical straight body at the top and an inverted conical cone at the bottom makes it easier to take out dry particles and spray liquid. It is preferable because the drops are easy to dry. The range of the ratio of the maximum length in the vertical direction to the maximum length in the horizontal direction (maximum length in the vertical direction / maximum length in the horizontal direction) (hereinafter referred to as “L / D”) is 0.1 to 10. If the L / D is out of this range, it will be difficult to manufacture the equipment, and it will take time and effort to operate and maintain and manage the equipment.

In the conventional method, it is known that when the slurry is spray-dried, the dried powder particles may be destroyed, the particle surface may be opened or depressed, and the particles may have an indefinite shape and become fragile. This is because the droplets shrink due to the evaporation of the liquid from the droplets, while the surface of the droplets solidifies, the pressure of the liquid inside the droplets increases, and the evaporation occurs in the form of sudden boiling. It is considered that this is because the powder particles are destroyed (cracked or chipped), the surface of the powder particles is opened, or the surface of the powder particles is depressed.
In the present invention, since the slurry of a specific raw material and composition is spray-dried under predetermined conditions, the strength of the entire catalyst particles spray-dried by close contact between the 8-membered ring-structured zeolite and the alumina particles in the alumina sol. Is improved, so that the above-mentioned problems are less likely to occur.

[Process: Firing process]
The method for producing a zeolite molded product of the present invention may further include a step of calcining the dry powder, if necessary, for the purpose of obtaining a zeolite molded product having higher collision durability.
The firing step is a step of heating the dry powder obtained in the spray drying step to activate the zeolaoite molded product, and to improve the hardness of the particles to impart collision durability.

The firing step can be performed using a muffle furnace, a rotary furnace, a tunnel furnace, a tube furnace, a fluid firing furnace, or the like.
The firing temperature is 400 ° C. to 900 ° C., preferably 450 ° C. to 800 ° C., and more preferably 500 ° C. to 700 ° C. If the calcination temperature is less than the above range, the activation of the catalyst may be insufficient, the selectivity of propylene may be insufficient, or the conversion rate of ethylene may be lowered. If the calcination temperature becomes higher than the above range, the activation effect is not improved, but on the other hand, the zeolite crystals may collapse and the catalytic performance may deteriorate.

The firing time is 0.1 hour to 10 hours. If the firing time is less than 0.1 hours, a sufficient firing effect may not be obtained, while if the firing time exceeds 10 hours, the catalyst performance is not improved and the productivity is lowered.
The firing step can be carried out under any conditions such as an oxygen atmosphere, an atmospheric atmosphere, an inert atmosphere, and a vacuum.
The firing step may be repeated.
Further, the alumina / 8-membered ring zeolite mass ratio and the SiO ₂ / Al _{2O 3} molar ratio in the produced zeolite molded product generally maintain the composition of the charged material.

[Process: Cyrilization process]
The method for producing a zeolite molded product of the present invention may further include a step of pre-silylating the 8-membered ring-structured zeolite for the purpose of improving selectivity in the production of propylene.
The silylation treatment includes liquid phase silylation using alkoxysilane and vapor phase silylation using chlorosilane, both of which may be carried out according to a conventional method.

For example, for liquid phase silylation, tetraethoxysilane or the like is dissolved in a desired solvent or added as it is to an 8-membered ring-structured zeolite in an amount of about 0.1 to 3 times by mass at 20 ° C to 140 ° C for 0.5 hours. It can be done by processing for about 24 hours. After the treatment, the zeolite is filtered and washed, and then dried to obtain a silylated zeolite.
In addition, vapor phase silylation is carried out using tetrachlorosilane or the like so that the amount of vapor-deposited silica is about 1% by mass to 20% by mass with respect to the 8-membered ring-structured zeolite under the conditions of about 20 ° C to 400 ° C. It can be a treated 8-membered ring structure zeolite.

The SiO ₂ / Al ₂ O ₃ molar ratio in the silylated 8-membered ring-structured zeolite is 15 to 2000, preferably 25 to 1500, more preferably 25 to 1200, and even more preferably 25 to 1200 in the case of aluminosilicate. Is 30 to 1000. In the case of silicoaluminophosphate, it is 0.2 to 100, preferably 0.25 to 80, and more preferably 0.25 to 50. Here, the SiO ₂ / Al ₂ O ₃ molar ratio of the silylated 8-membered ring-structured zeolite is such that the silylated 8-membered ring-structured zeolite is dissolved in an alkaline aqueous solution and the obtained solution is subjected to plasma emission spectroscopy. It can be obtained by analyzing by an analytical method.

The average particle size of the 8-membered ring-structured zeolite when the 8-membered ring-structured zeolite is silylated is also preferably 0.05 μm or more, similar to the above-mentioned average particle size of the preferred 8-membered ring-structured zeolite. It is 50 μm, more preferably 0.3 μm to 20 μm, and even more preferably 0.5 μm to 4 μm. By setting the average particle size of the silylated 8-membered ring-structured zeolite within the above range, a zeolite molded body having excellent collision durability and catalytic activity can be obtained. Examples of adjusting to the average particle size include a method of pulverizing an 8-membered ring-structured zeolite that has been silylated by a silylation treatment step, and a method of pulverizing the zeolite and then performing a silylation treatment. If it is possible to adjust, either of the above two methods or a combination of the above methods may be used.

<Propene manufacturing method>
The zeolite molded product produced by the above production method is essentially a catalyst suitable for producing lower olefins having different carbon atoms from various lower olefins having 2 to 4 carbon atoms. Therefore, although not particularly limited, at least one selected from the group consisting of ethylene and / or ethanol, methanol and dimethyl ether as an example of a catalytic reaction exhibiting a remarkable effect by using the zeolite molded product produced by the method of the present invention as a catalyst. An example of producing propylene from a hydrocarbon raw material containing one type using ethylene as a main raw material will be briefly described below.

1. 1. Raw Material As described above, ethylene is mentioned as a raw material for producing propylene using the zeolite molded product of the present invention as a catalyst.
The ethylene equivalent content based on the hydrocarbon compound in the raw material to be supplied to the catalyst is not particularly limited, but from the viewpoint of productivity, the ethylene equivalent content is preferably 20% by mass or more, more preferably 30% by mass. Above, more preferably 50% by mass or more.
In addition to ethylene, the above-mentioned charged raw materials may contain alkanes such as methane, ethane and propane, olefins such as propylene, butene and hexene, and other alkynes such as acetylene. Alcohols such as ethanol and methanol, ethers such as dimethyl ether and the like may be contained.
In addition, water (water vapor), hydrogen, nitrogen, carbon dioxide, carbon monoxide and the like may be contained as long as the performance of the catalyst of the present invention is not impaired.

2. 2. Method for Producing Propylene When producing propylene using the zeolite molded product of the present invention, the above ethylene or a raw material mixture containing ethylene is supplied to a fluidized bed reactor charged with the zeolite molded product and contacted. It is preferable to use a method of converting ethylene to propylene.
The method for producing propylene using the present zeolite molded product will be described below.

(1) Steam Treatment of Zeolite Molded Body Before starting the supply of ethylene, for example, the zeolite molded product of the present invention is steam-treated at a temperature of 300 ° C. to 900 ° C. under the condition of a partial pressure of steam of 0.01 atm or more. Can be done. In the heat treatment in the presence of water vapor, nitrogen and / or oxygen or the like may be contained as a gas component other than water vapor.
By performing the steam treatment, in the production of propylene using the zeolite molded body of the present invention, deterioration of the zeolite molded body due to the deposition (caulking) of carbonaceous components on the zeolite molded body can be suppressed, and the propylene yield can be suppressed.・ Yield may improve.

(2) Reaction Conditions The reaction temperature in the method for producing propylene using the zeolite molded product of the present invention is preferably in the range of 300 ° C to 500 ° C, more preferably in the range of 300 ° C to 400 ° C. The reaction pressure is preferably in the range of 0.01 MPa to 1 MPa (absolute pressure) and more preferably in the range of 0.1 MPa to 0.7 MPa (absolute pressure).

The supply rate of ethylene to the reactor is preferably 1 to 100 mmol / (g-zeo · h) as the mass-based (g-zeo) space velocity (WHSV) of the zeolite molded product of the present invention, and is 5 to 5. It is more preferably 70 mmol / (g-zeo · h).
Under the above conditions, the gas flow rate in the fluidized bed reactor is set to 0.1 m / sec to 1.5 m / sec, preferably 0.1 m / sec to 1.0 m / sec, more preferably 0.2 m / sec. By setting the range to about 1.0 m / sec, propylene can be produced efficiently and stably.

(3) Fluidized Bed Reactor In the method for producing propylene using the zeolite molded product of the present invention, it is preferable to use a fluidized bed reactor as the reactor.
There are fluidized bed reactors and riser reactors as fluidized bed reactors, both of which can be used, but from the viewpoint of separation and recovery of zeolite molded products and efficient and stable production of propylene, fluidized beds It is preferable to use a type reactor.

As the structure of the fluid bed type reactor, a gas dispersion tube for supplying raw material gas is provided at the bottom of the reactor and / or at the bottom of the reactor, and the thick layer and the dilute layer of the zeolite molded body are used for slow heating as needed. A reactor having a cooling coil of the above and having a cyclone for separating the reaction gas and the zeolite molded body at the upper part in the reactor can be mentioned. The cyclone can also be installed outside the reactor.

(4) Ethylene conversion rate The ethylene conversion rate in the method for producing propylene using the zeolite molded product of the present invention can be obtained by analyzing the product using gas chromatography and using the following formula (1).
Ethylene conversion rate (%) = [[reactor inlet ethylene (mol) -reactor outlet ethylene (mol)] / reactor inlet ethylene (mol)] x 100 (1)

(5) Propylene selectivity In the method for producing propylene using the zeolite molded product of the present invention, the selectivity of propylene can be analyzed by gas chromatography and obtained by the following formula (2).
Propene selectivity (%) = [reactor outlet propylene-derived carbon (mol) / [reactor outlet total carbon (mol) -reactor outlet ethylene-derived carbon (mol)]] x 100 (2)

(6) Yield of Propylene The yield of propylene is obtained by the product of the ethylene conversion rate and the selectivity of the produced propylene, and can be calculated by the following formula (3).
Propene yield (%) =
(Ethylene conversion rate (%) x propylene selectivity (%)) / 100 (3)

(6) Recovery / Reuse of Raw Materials In the method for producing propylene using the zeolite molded product of the present invention, the gas flow after separating propylene from the outflow gas from the reactor removes some high boiling point components. Therefore, it is preferable to circulate it in the reactor and reuse it.
As a method for separating propylene from the outflow gas of the fluidized bed reactor, distillation separation or the like may be used, and the gas flow after separating propylene contains a low boiling component such as ethylene and a high boiling component such as butene. Therefore, it is efficient to remove some of the components having a higher boiling point and then circulate and reuse them in the fluidized bed reactor as a part of the raw material gas.
The amount and ratio of reuse are not particularly limited, and it is sufficient to adjust the amount and ratio according to the production amount of propylene.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[Measurement method of various physical properties]
The methods for measuring various physical properties are as follows.
(1) Wear loss of the zeolite molded body The wear loss, which is an index of the wear resistance of the zeolite molded body, was measured using a spray type flow device. The spray type flow device has an inner diameter of 37.1 mm and a length of 700 mm, a "powder rising part", and an inner diameter of 133.8 mm and a length of 580 mm, a "powder separation part" in which an orifice having one 0.7 mm hole is installed in the gas inlet. , "Fine powder collecting part". A cone-shaped "metal shielding portion" having a diameter of 20 mm and opening at 60 ° is installed at a position 10 mm from the orifice in the "powder rising portion". 25 cc (charge weight (A)) of the zeolite molded body dried at 140 ° C. is put into the "powder separation part", and then 5.0 L / 50 of air containing water equivalent to the vapor pressure is introduced from the "gas inlet". Blow for 2 hours in seconds to allow the zeolite molding to flow. The fluidized zeolite molding collides with the "metal shield", and a part of it is crushed into fine powder. The zeolite molded body that has become fine powder is collected in the "fine powder collecting section". The weight (B) of the recovered fine powder zeolite molded body was measured, and the wear loss was determined according to the following formula.
Wear loss (% by mass) = B / A x 100
The smaller the wear loss, the better the collision durability.

(2) Bulk Density of Zeolite Molded Body The bulk density of the zeolite molded product was measured using a JIS standard Z-2504 bulk specific gravity measuring instrument (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.) according to the attached manual.

(3) Angle of repose of the zeolite molded product The angle of repose of the zeolite molded product is a granulation manual (Nippon Kakutai Kogyo Co., Ltd.) at a rotation speed of 10 rpm using a three-wheeled cylindrical rotary flow surface angle measuring instrument (manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). It was measured using the angle of repose method described in (Ohm Co., Ltd., edited by the Association).

(4) Ethylene conversion rate, propylene selectivity, propylene yield Calculated by the above method.

[Catalyst preparation method]
(1) Cyrilized Zeolite To 5.0 kg of proton-type aluminosilicate (SiO ₂ / Al ₂ O ₃ = 25, zeolite) having a CHA structure synthesized by the method described in US Pat. No. 4,544,538. 43.0 kg of toluene was added, and the mixture was stirred at room temperature for 1 hour. Then, 2.97 kg of tetraethoxysilane was added, and the silylation treatment was carried out by heating at 70 ° C. for 3 hours. After the treatment, filtration and washing were performed, and the obtained aluminosilicate was dried under reduced pressure at 80 ° C.

Then, the zeolite treated with the above silylation was crushed by a jet mill. When the crushed zeolite was measured with a laser diffraction / scattering type particle size distribution meter, the average particle size was 2.6 μm. Hereinafter, the crushed zeolite is referred to as Zeolite 1.

(Example 1)
Using the above "zeolite 1" as an alumina binder, Catalyst AP-1 (manufactured by JGC Catalysts and Chemicals Co., Ltd., aluminum concentration 71.0% by mass) is added to a slurry previously dispersed in water to prepare a slurry, and a spray dryer manufactured by Pris Co., Ltd. is prepared. (TR160, spray method: rotary disk type) is used to spray dry under the conditions of an inlet gas temperature of 150 ° C. and an outlet gas temperature of 90 ° C., and then calcined at 550 ° C. for 8 hours to prepare a zeolite molded body 1. did. The wear loss, bulk density and angle of repose of the obtained zeolite forming body 1 were measured according to the above measuring method. The results obtained are shown in Table 1.

Next, the zeolite molded body 1 was filled in a stainless steel reaction tube using a fixed-bed flow reactor. The reaction and regeneration are repeated by supplying the reactor so that the space velocity of ethylene is 50 mmol / (g-zeo · h) based on the zeolite mass and the space velocity of hydrogen is 50 mmol / (g-zeo · h) based on the zeolite mass. Evaluation was performed. When the product when the reaction integration time reached 20 hours was analyzed by gas chromatography, the ethylene conversion was 89.1%, the propylene selectivity was 80.4%, and the propylene yield was 71.6%. rice field. Analysis of the products when the reaction integration time reached 400 hours revealed that the ethylene conversion was 81.0%, the propylene selectivity was 83.3%, and the propylene yield was 67.5%.

(Example 2)
Spray drying and firing in the same manner as in Example 1 above, except that the "zeolite 1" was added to aluminum sol-A2 (manufactured by Kawaken Fine Chemical Co., Ltd., alumina concentration 9.9% by mass) as an alumina binder to prepare a slurry. 2 was prepared, and the same measurement was performed. The results obtained are shown in Table 1.
The reaction / regeneration of propylene production was repeatedly evaluated under the same conditions as in Example 1 except that the zeolite molded body 2 was used instead of the zeolite molded body 1. When the product when the reaction integration time reached 20 hours was analyzed by gas chromatography, the ethylene conversion was 90.0%, the propylene selectivity was 81.8%, and the yield was 73.6%. .. Analysis of the products when the reaction integration time reached 400 hours revealed that the ethylene conversion was 84.9%, the propylene selectivity was 84.4%, and the propylene yield was 71.7%.

(Comparative Example 1)
Snowtex NXS (manufactured by Nissan Chemical Industries, Ltd., slurry concentration 14.5% by mass), phosphoric acid (Wako Pure Chemical Industries, Ltd., reagent special grade), and boric acid (Wako Pure Chemical Industries, Ltd.) as silica sol in the "zeolite 1" Slurry is prepared by adding Reagent Special Grade Co., Ltd.), and conditions of inlet gas temperature 250 ° C and outlet gas temperature 150 ° C using a mobile minor type spray dryer (spray drying method: rotary disk type) manufactured by Niro Atomizer. After spray-drying at 550 ° C. for 8 hours, the zeolite molded body 3 was prepared. The wear loss, bulk density and angle of repose of the obtained zeolite forming body 3 were measured according to the above measuring method. The results obtained are shown in Table 1. Next, the zeolite molded body 3 was filled in a stainless steel reaction tube using a fixed-bed flow reactor. The reaction and regeneration are repeated by supplying the reactor so that the space velocity of ethylene is 35 mmol / (g-zeo · h) based on the zeolite mass and the space velocity of hydrogen is 35 mmol / (g-zeo · h) based on the zeolite mass. Evaluation was performed. When the product when the reaction integration time reached 20 hours was analyzed by gas chromatography, the ethylene conversion was 89.4%, the propylene selectivity was 86.1%, and the propylene yield was 77.0%. rice field. Analysis of the products when the reaction integration time reached 400 hours revealed that the ethylene conversion was 69.5%, the propylene selectivity was 88.8%, and the propylene yield was 61.7%.

(Comparative Example 2)
Snowtex NXS (manufactured by Nissan Chemical Industries, Ltd., slurry concentration 14.5% by mass), phosphoric acid (Wako Pure Chemical Industries, Ltd., reagent special grade), and boric acid (Wako Pure Chemical Industries, Ltd.) are added to the above-mentioned "zeolite 1" as silica sol. Slurry is prepared by adding Reagent Special Grade Co., Ltd.), and conditions of inlet gas temperature 250 ° C and outlet gas temperature 150 ° C using a mobile minor type spray dryer (spray drying method: rotary disk type) manufactured by Niro Atomizer. After spray-drying at 550 ° C. for 8 hours, the zeolite molded body 4 was prepared. The wear loss, bulk density and angle of repose of the obtained zeolite forming body 4 were measured according to the above measuring method. The results obtained are shown in Table 1.
Next, the zeolite molded body 4 was filled in a stainless steel reaction tube using a fixed-bed flow reactor. The reaction and regeneration are repeated by supplying the reactor so that the space velocity of ethylene is 35 mmol / (g-zeo · h) based on the zeolite mass and the space velocity of hydrogen is 35 mmol / (g-zeo · h) based on the zeolite mass. Evaluation was performed. When the product when the reaction integration time reached 20 hours was analyzed by gas chromatography, the ethylene conversion was 92.5%, the propylene selectivity was 74.5%, and the propylene yield was 78.2%. rice field. Analysis of the products when the reaction integration time reached 400 hours revealed that the ethylene conversion was 85.9%, the propylene selectivity was 78.9%, and the propylene yield was 67.8%.

The following points were found from Table 1.
(1) The zeolite molded bodies of Examples 1 and 2 that satisfy the requirements specified in the present application have low wear loss. That is, it has excellent collision durability. Further, since the angle of repose is within a specific range, the fluidity is good and it is easy to handle. In addition, since the bulk density is within a specific range, it has effective performance when used as a catalyst in a fluidized bed reaction. Looking at the results of the production of propylene of Examples 1 and 2, high propylene selectivity and high productivity are achieved, and the performance is maintained for a long period of time, so that it can be suitably used for a fluidized bed type reactor.

(2) On the other hand, in Comparative Examples 1 and 2 which do not satisfy the requirements specified in the present application, both collision durability and stable and high proprene productivity are not compatible. That is, although the value of wear loss is small in Comparative Example 1, in the production of propylene, a large amount of phosphoric acid contained inhibits the reaction, so that the performance as a catalyst deteriorates and the stable maintenance of the catalyst performance for a long period of time is maintained. Can not. Further, in Comparative Example 2, the amount of phosphoric acid and boric acid contained is small, the degree of inhibition of the reaction is small in the production of propylene, and a fairly stable catalytic performance can be obtained, while the amount of phosphoric acid and boric acid contained is small. The value of wear loss is large and it does not have collision durability. It is easily expected that in the production of propylene in a fluidized bed reactor, the zeolite molded product becomes miniaturized in a short time, causing a deterioration in performance as a catalyst, or being discharged to the outside of the reaction system. Therefore, it is considered difficult to use it in a fluidized bed type reactor.

The zeolite molded product and the zeolite molded product obtained by the method for producing a zeolite molded product of the present invention have excellent collision durability, a good shape, and improved selectivity and productivity in the production of propylene, and the selection thereof. As a catalyst that can industrially produce propylene with high productivity by using a fluidized bed reactor with high selectivity using ethylene as a raw material because the property and productivity continue to be stable for a long time. It is useful.

Claims (8)

A zeolite molded body containing at least a part of an 8-membered ring-structured zeolite and alumina having a silylation treatment and having an angle of repose of 20 to 35 °. The first aspect of claim 1, wherein the zeolite molded body contains at least a partially silylated 8-membered ring-structured zeolite and alumina and has a bulk density of 0.5 to 1.3 g / cm ³ . Zeolite molded body. The zeolite molded product according to claim 1 or 2, wherein the mass ratio of alumina to the mass of the 8-membered ring-structured zeolite is 10 or less. The proportion of the zeolite molded body that is crushed when the zeolite catalyst is made to collide with the metal plate by blowing air containing water equivalent to the vapor pressure at 5.0 L / 50 seconds for 2 hours is 3% by mass or less. The zeolite molded product according to any one of claims 1 to 3, wherein the zeolite molded product is characterized by the above-mentioned. The zeolite molded product according to any one of claims 1 to 4, wherein the 8-membered ring-structured zeolite is a CHA-type zeolite. The zeolite molded product according to any one of claims 1 to 5 , wherein the 8-membered ring-structured zeolite is a zeolite having an average particle size of 0.1 to 50 μm. The method for producing a zeolite molded product according to any one of claims 1 to 6, wherein the 8-membered ring-structured zeolite having at least a partially silylated treatment and alumina are molded. A lower grade comprising a step of contacting the zeolite molded product according to any one of claims 1 to 6 with a hydrocarbon raw material containing at least one selected from the group consisting of ethylene, ethanol, methanol, and dimethyl ether. Method for producing olefin.