JP2023046749A - Catalyst for producing butadiene, apparatus for producing butadiene, and method for producing butadiene - Google Patents

Abstract

To provide a catalyst for producing butadiene, an apparatus for producing butadiene, and a method for producing butadiene, which can suppress variation in productivity of butadiene, where the variation in productivity of butadiene is caused by "bridging" of the catalyst, which makes filling of catalyst in a reaction tube uneven to cause variation of flow quantity of a raw material gas and productivity of butadiene; a phenomenon termed "bridging" sometimes occurs when filling granular catalysts in a reaction tube of a production apparatus due to contact of the catalysts with each other and the catalysts become stuck at a higher position than an intended filling position in the reaction tube.SOLUTION: Provided is a catalyst for producing butadiene, used in a method for producing butadiene, in which butadiene is produced from a raw material including ethanol. The catalyst comprises a group of granular particles and has an average particle size of 1 to 8 mm and an average sphericity of 0.89 to 1.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a butadiene production catalyst, a butadiene production apparatus, and a butadiene production method.

Butadiene such as 1,3-butadiene is used as a raw material for styrene-butadiene rubber (SBR) and the like. Traditionally, butadiene was purified from the C4 fraction. The C4 fraction is a by-product of naphtha cracking to synthesize ethylene from petroleum. However, the use of oil decreased as the use of shale gas increased. As a result, the production of butadiene from naphtha cracking of petroleum is also decreasing. Therefore, alternative methods for producing 1,3-butadiene are sought.

As a method for producing butadiene, for example, a method of converting ethanol to acetaldehyde in the presence of a catalyst and then converting ethanol and acetaldehyde to 1,3-butadiene is known (see, for example, Patent Document 1).

Japanese Patent Publication No. 2017-532318

In the production of butadiene, a solid and granular catalyst is used to ensure the flow rate of the raw material gas. When a granular catalyst is packed into a reaction tube of a manufacturing apparatus, a phenomenon called "bridging" may occur in which the catalysts come into contact with each other and become stuck at a position higher than the intended packing position in the reaction tube.
When "bridging" occurs, the filling of the catalyst in the reaction tube becomes non-uniform, the flow rate of the raw material gas fluctuates, and the productivity of butadiene fluctuates.

Accordingly, an object of the present invention is to provide a catalyst for producing butadiene, an apparatus for producing butadiene, and a method for producing butadiene, which can suppress variations in productivity of butadiene.

In order to solve the above problems, the present invention has the following aspects.
[1] A butadiene production catalyst used in a butadiene production method for producing butadiene from a raw material containing ethanol,
a group of spherical particles,
A catalyst for producing butadiene, having an average particle diameter of 1 to 8 mm and an average sphericity of 0.89 or more and 1 or less.
[2] The catalyst for producing butadiene according to [1], which has an angle of repose of 20° or less.
[3] The catalyst for producing butadiene according to [1] or [2], which has an average crushing strength of 10 to 150 [N].

[4] A butadiene production apparatus comprising a reaction tube filled with the butadiene production catalyst according to any one of [1] to [3], a product discharge pipe, and a first filter,
The product discharge pipe is connected to the outlet of the reaction tube,
The first filter is located at a connection portion between the reaction tube and the product discharge pipe,
The apparatus for producing butadiene, wherein the mesh size of the first filter is 50% or less of the average particle size.
[5] further comprising a second filter;
The second filter is located downstream of the first filter in the product discharge pipe,
The apparatus for producing butadiene according to [4], wherein the mesh size of the second filter is 25% or less of the average particle size.
[6] Further comprising a third filter,
The third filter is located downstream of the second filter in the product discharge pipe,
The apparatus for producing butadiene according to [5], wherein the mesh size of the third filter is 70% or less of the average particle size of fragments when the catalyst for producing butadiene is cracked.

[7] A method for producing butadiene, comprising a step of bringing a raw material containing ethanol into contact with the butadiene production catalyst according to any one of [1] to [3] to produce butadiene.
[8] A butadiene production method for producing butadiene from a raw material containing ethanol using the butadiene production apparatus according to any one of [4] to [6],
A method for producing butadiene, comprising a step of supplying the raw material to the reaction tube and bringing the raw material into contact with the catalyst for producing butadiene to produce butadiene.

According to the catalyst for producing butadiene, the apparatus for producing butadiene, and the method for producing butadiene of the present invention, variations in productivity of butadiene can be suppressed.

1 is a schematic diagram of a butadiene production apparatus according to an embodiment of the present invention. FIG.

≪Butadiene production catalyst≫
The catalyst for producing butadiene of the present invention is a catalyst for synthesizing butadiene from a raw material containing ethanol.

As used herein, the “particle diameter” of the butadiene-producing catalyst means the average value ((D _L +D _S )/2) of the major diameter (D _L ) and the minor diameter (D _S ) of the butadiene-producing catalyst. do. Here, the "major axis" is the longest diameter of the particles of the catalyst for producing butadiene when viewed in plan from an arbitrary direction, and the "minor axis" is the diameter in the direction perpendicular to the major axis. The major axis and minor axis of the catalyst for producing butadiene can be measured, for example, with an optical microscope (eg, Digital Microscope VHX-7000 manufactured by Keyence Corporation).
In the present specification, the "average particle size" of the catalyst for producing butadiene is obtained by randomly selecting 50 particles of the catalyst for producing butadiene, measuring the particle size of each, and averaging the values. be able to.

In the present specification, the “sphericity” of the catalyst for producing butadiene is a value represented by the ratio (D _S /D _L ) of the major diameter (D _L ) and the minor diameter (D _S ) of the butadiene production catalyst. is. The upper limit of the sphericity is 1, and when the major axis and the minor axis are equal, the sphericity is 1, which means a true sphere.
In the present specification, the “average sphericity” of a butadiene-producing catalyst means that 50 particles of a butadiene-producing catalyst are randomly selected, the sphericity is measured for each, and the values are averaged. can be obtained by

The average particle size of the catalyst for producing butadiene is 1 to 8 mm, preferably 1.1 to 4 mm, more preferably 1.18 to 3 mm. When the average particle size of the catalyst for producing butadiene is at least the above lower limit, a sufficient contact area with the raw material gas can be ensured. When the average particle size of the butadiene-producing catalyst is equal to or less than the above upper limit, the filling rate of the butadiene-producing catalyst in the reaction tube can be increased. Therefore, the production efficiency of butadiene can be further improved.

The catalyst for producing butadiene of the present embodiment is a group of spherical particles. Since the shape of the butadiene-producing catalyst is spherical, the particles of the butadiene-producing catalyst are in point contact, not surface contact. Therefore, since the filling state tends to be uniform, it becomes difficult for the raw material to flow unevenly. Furthermore, sticking between particles is also suppressed. As a result, variations in productivity of butadiene can be suppressed.

The average sphericity of the catalyst for producing butadiene is 0.89 or more and 1 or less, preferably 0.91 or more and 1 or less, and more preferably 0.93 or more and 1 or less. When the average sphericity of the catalyst for producing butadiene is equal to or higher than the above lower limit, the catalyst can be uniformly filled in the reaction tube, and variations in productivity of butadiene can be suppressed.

The angle of repose of the catalyst for producing butadiene is preferably 20° or less, more preferably 18° or less, and even more preferably 16° or less. When the angle of repose of the catalyst for producing butadiene is equal to or less than the above upper limit, sufficient fluidity can be ensured, and the filling rate of the catalyst for producing butadiene in the reaction tube can be increased. Therefore, the production efficiency of butadiene can be further enhanced.
As used herein, the "angle of repose" of a catalyst for producing butadiene means an angle measured by the following method. A cylindrical auxiliary jig with an inner diameter of 5 cm is placed on a flat cylindrical pedestal (6 cm in diameter), and 30 g of a catalyst for producing butadiene is placed in the auxiliary jig. Move the auxiliary jig vertically upward and remove it from the pedestal. The angle (acute angle) formed between the horizontal plane on the pedestal and the slope of the mountain while the mountain of the catalyst for producing butadiene formed at this time does not spontaneously collapse and maintains stability is referred to as the "angle of repose." do. The angle of repose of the catalyst for producing butadiene can be measured using, for example, a protractor. Although the lower limit of the angle of repose of the catalyst for producing butadiene is not particularly limited, it is, for example, 5°.

The average crushing strength of the catalyst for producing butadiene is preferably 10 to 150 [N], more preferably 30 to 90 [N], even more preferably 40 to 80 [N]. When the average crushing strength of the butadiene-producing catalyst is equal to or higher than the above lower limit, the butadiene-producing catalyst is less likely to be destroyed, and the reaction tube and part of the piping subsequent to the reaction tube are less likely to be clogged. As a result, pressure loss and drift of the raw material are less likely to occur, and the production efficiency of butadiene is improved. When the average crushing strength of the butadiene-producing catalyst is equal to or less than the above upper limit, sticking between the pipes and the butadiene-producing catalyst is suppressed, so that the pipes can be easily washed when replacing the catalyst, and maintainability is improved.

As used herein, the "crushing strength" of the catalyst for producing butadiene can be measured according to JISZ8841:1993.
The "crushing strength" of the catalyst for producing butadiene can also be measured by the following method. Compressive strength tester (electric stand (model number: MX2-500N-L, manufacturer: Imada Co., Ltd.), digital force gauge (model number: ZTS-100N, manufacturer: Corporation) Imada)) is set in the center on the fixed compression surface. The fixed compression surface and the working compression surface of the compressive strength tester are positioned to contact the particles, and the movable pressure platen is operated at a constant speed to apply a load to the particles. The pressurization speed is set to 300 mm/min, and the maximum indicated value of the load until the particles are completely broken is recorded, and this value can be used as the crushing strength of the catalyst for producing butadiene.
As used herein, the “average crushing strength” of a catalyst for producing butadiene is obtained by randomly selecting 50 particles of the catalyst for producing butadiene, measuring the crushing strength of each, and averaging the values. be able to.

It is preferable that the average particle size distribution of the catalyst for producing butadiene is as narrow as possible. The average particle size distribution of the catalyst for producing butadiene can be represented by the existence ratio of particles having a specific average particle size.
For example, among the 100 particles of the catalyst for producing butadiene randomly selected in the measurement of the average particle size described above, the proportion of particles having an average particle size of ±33% is preferably 80% or more, and 90%. % or more is more preferable, and 96.7% or more is even more preferable. When the proportion of particles having an average particle diameter of ±33% is equal to or higher than the above lower limit, the average particle diameter distribution of the catalyst for producing butadiene is sufficiently narrow, and the filling state tends to be uniform. As a result, adhesion of the catalysts to each other is suppressed, and drifting of the raw material is less likely to occur. As a result, variations in productivity of butadiene can be further suppressed.

A specific configuration of the catalyst for producing butadiene of the present embodiment will be described below.

(active metal)
The butadiene production catalyst contains an active metal. Examples of active metals include metals such as hafnium, zirconium, copper, tantalum, niobium, magnesium, zinc, and silver. From the viewpoint of catalytic activity, hafnium, zirconium, tantalum, and niobium are preferred, and hafnium and zirconium are more preferred. preferable. Only one type of active metal may be used, or two or more types may be used in combination.

Forms of active metals include inorganic salts such as oxides, chlorides, sulfides, nitrates, and carbonates; organic salts such as oxalates, acetylacetonate salts, dimethylglyoxime salts, ethylenediamine acetate salts; Carbonyl compounds, cyclopentadienyl compounds, ammine complexes, alkoxide compounds, alkyl compounds and the like are exemplified, among which oxides are preferred from the viewpoint of increasing the production efficiency of butadiene. The active metal may form a composite oxide with an element other than oxygen in the carrier described below. When two or more active metals are used in combination, a composite oxide of these two or more elements may be formed.

(Carrier)
The butadiene-producing catalyst is preferably a supported catalyst in which the above-described active metal is supported on a carrier.
Examples of the carrier for the butadiene production catalyst include silica, titania, alumina, zirconia, zeolite, magnesia and calcia, with silica, titania and zirconia being preferred, and silica being particularly preferred. Silica has various products with different specific surface areas and pore diameters. Butadiene selectivity and raw material conversion can be controlled by combining the specific surface area and pore diameter of the carrier. Only one type of carrier may be used, or two or more types may be used in combination.

Among the above carriers, porous silica is preferably used as the carrier. Mesoporous silica, for example, can be used as the porous silica.

(Composition of catalyst for producing butadiene)
When the butadiene-producing catalyst is a supported catalyst in which an active metal is supported on a carrier, the supported amount of the active metal in terms of oxide is preferably 0.2 to 80% by mass with respect to the total mass of the butadiene-producing catalyst. 2 to 60% by mass is more preferable, and 4 to 50% by mass is even more preferable. When the supported amount of the active metal in terms of oxide is at least the above lower limit, a sufficient amount of the active metal can be supported, and the raw material conversion rate and butadiene selectivity are further increased. When the supported amount of the active metal in terms of oxide is equal to or less than the above upper limit, the active metal is easily dispersed uniformly and highly, so that the butadiene selectivity is further increased.

The catalyst for producing butadiene of the present embodiment preferably contains hafnium and the element M. Element M is at least one element selected from the group consisting of titanium and zirconium. As the element M, zirconium is preferred. The ratio of the number of moles of the element M to the number of moles of hafnium in the catalyst for producing butadiene is preferably more than 20 and 500 or less, more preferably more than 50 and 400 or less, and further preferably more than 100 and 400 or less. It is preferably more than 100 and 300 or less, particularly preferably. When the molar ratio is within the range, the yield of butadiene increases.

The total pore volume of the butadiene production catalyst (hereinafter also referred to as total pore volume) is preferably 0.1 to 10 mL/g, more preferably 0.1 to 5 mL/g, and 0.1 to 2 mL/g. is more preferred. When the total pore volume is at least the above lower limit, the diffusibility of ethanol-containing raw materials into the catalyst for producing butadiene is improved, and the raw material conversion rate and butadiene selectivity are further increased. When the total pore volume is equal to or less than the above upper limit, the contact area between the raw material and the catalyst for producing butadiene tends to be sufficient, and the raw material conversion rate and butadiene selectivity are further increased.
The total pore volume of the catalyst for producing butadiene is a value measured by a water titration method. The water titration method is a method in which water molecules are adsorbed on the surface of a catalyst for producing butadiene and the pore volume is measured from condensation of the molecules.

The average pore diameter of the catalyst for producing butadiene is preferably 2 to 50 nm, more preferably 2 to 30 nm, still more preferably 2 to 20 nm, and particularly preferably 2 to 15 nm. When the average pore diameter is at least the above lower limit, the diffusibility of the ethanol-containing raw material into the catalyst for producing butadiene is improved, and the raw material conversion rate is further increased. In addition, when the average pore diameter is at least the above lower limit, the acid strength on the surface of the catalyst does not become too strong, so side reactions can be suppressed, and as a result, butadiene selectivity increases. When the average pore diameter is equal to or less than the above upper limit, a sufficient amount of active sites are present on the catalyst surface, so that the raw material conversion rate and butadiene selectivity are further increased.

The average pore diameter is a value calculated from the total pore volume and BET specific surface area. The BET specific surface area is a value calculated from the adsorption amount of nitrogen as an adsorbed gas and the pressure at that time. Specifically, it can be calculated by assuming that the pore shape is cylindrical. Using the BET specific surface area A1 as the cylindrical side area and the total pore volume V1 as the cylindrical volume, the average pore diameter _Dave1 can be calculated by the following formula (I).
_Dave1 = 4V1/A1 (I)

Average pore diameter can also be measured by a mercury intrusion porosimeter. In the mercury intrusion method, mercury is pressurized and injected into the pores of a catalyst for producing butadiene, and the average pore diameter is calculated from the pressure and the amount of injected mercury based on the principle of capillary action.
Using the pressure P at which mercury is injected, the surface tension γ of the pore mercury of the catalyst, and the contact angle θ, the pore diameter can be calculated by the following formula (II). The average pore diameter D _ave2 is the average value of D ₂ calculated as a function of P according to formula (II) below.
D ₂ =−(1/P)4γ cos θ (II)

The specific surface area of the catalyst for producing butadiene is preferably 100 to 10000 m ² /g, more preferably 200 to 5000 m ² /g, even more preferably 200 to 1500 m ² /g. When the specific surface area of the catalyst for producing butadiene is equal to or higher than the above lower limit, a sufficient amount of active sites are present on the surface of the catalyst, so that the raw material conversion rate and butadiene selectivity are further increased. When the specific surface area of the catalyst for producing butadiene is equal to or less than the above upper limit, the average pore diameter does not become too small, the diffusibility of the raw material containing ethanol into the catalyst for producing butadiene is improved, and the raw material conversion rate is further increased. .
The specific surface area is a BET specific surface area measured by a BET gas adsorption method using nitrogen as an adsorption gas.

The product of the total pore volume and the specific surface area in the catalyst for producing butadiene is preferably 10 to 100000 mL·m ² /g ² , more preferably 20 to 25000 mL·m ² /g ² and 20 to 3000 mL·m ² /g. ² is more preferred. When the product of the total pore volume and the specific surface area is equal to or higher than the above lower limit, a sufficient amount of active sites are present on the catalyst surface, thereby further increasing the raw material conversion rate and the butadiene selectivity. When the product of the total pore volume and the specific surface area is equal to or less than the above upper limit, the surface of the catalyst that does not become active sites does not become too large, side reactions can be suppressed, and as a result, the butadiene selectivity is further increased.

The total pore volume of the mesopores (pores with a pore diameter of 2 to 50 nm) in the butadiene production catalyst of the present embodiment (hereinafter also referred to as the total mesopore volume) is, with respect to the total pore volume, It is preferably 50 to 100%, more preferably 80 to 100%, even more preferably 90 to 100%.
When the total mesopore volume relative to the total pore volume is at least the above lower limit, sufficient mesopores are present in the butadiene production catalyst, and the diffusion of the raw material containing ethanol into the butadiene production catalyst is improved. Therefore, the raw material conversion rate and butadiene selectivity are further increased.
The total pore volume of the catalyst for producing butadiene is a value measured by the water titration method described above. The total mesopore volume of the catalyst for producing butadiene can be obtained by measuring the volume of pores having pores of 2 to 50 nm by a nitrogen adsorption method and totaling them.

<Method for producing catalyst for producing butadiene>
A catalyst for producing butadiene can be produced, for example, by supporting an active metal on a carrier, followed by drying and calcination.

The method for producing the carrier is not particularly limited, and one produced by a conventionally known production method may be used, or a commercially available product may be used.

For example, a method for producing silica as a carrier includes, for example, a sol-gel method in which a compound containing silicon element and a solution containing an inorganic acid are mixed. Examples of the silicon-containing compound include sodium silicate, potassium silicate, and ammonium silicate. Examples of the inorganic acid include sulfuric acid, nitric acid, and hydrochloric acid.

The silica obtained is shaped and granulated. When granulating, a method of granulating while rotating, such as a tumbling granulation method, or a method of granulating spherical silica by isotropically enlarging the particle size using a vapor phase growth method or a liquid phase growth method. etc. Alternatively, silica whose sphericity has been previously adjusted to 0.89 or more may be purchased and used as a carrier.

A carrier can be produced by calcining the obtained silica molded body or granule in an air atmosphere. The firing temperature is preferably 600 to 1200°C, more preferably 700 to 1100°C, even more preferably 750 to 1050°C. When the calcination temperature is equal to or higher than the above lower limit, it becomes easier to obtain a catalyst for producing butadiene having the crushing strength described above. A decrease in the specific surface area is suppressed when the firing temperature is equal to or lower than the upper limit.

Commercially available products can also be used as the silica moldings or granules having the above properties. Examples of commercially available products include Caract Q series manufactured by Fuji Silysia Chemical Co., Ltd. and the like.

Compounds containing a catalytically active element include, for example, inorganic salts such as chlorides, chloride oxides, sulfides, nitrates, and carbonates of the catalytically active element, oxalates, acetylacetonate salts, and dimethylglyoxime salts. , organic salts such as ethylenediamine acetate, chelate compounds, carbonyl compounds, cyclopentadienyl compounds, ammine complexes, alkoxide compounds, alkyl compounds and the like.
Among them, the above compound is preferably a chloride or a chloride oxide. Moreover, you may use a hydrate for the said compound as needed.
Specific examples of compounds containing catalytically active elements include hafnium chloride (HfCl ₄ ), titanium chloride (TiCl ₂ , TiCl ₃ , TiCl ₄ ), titanium alkoxide, zirconium chloride (ZrCl ₄ ), and zirconium chloride oxide (ZrCl ₂ O). , zirconium alkoxide, hafnium alkoxide and the like.
In addition, the said compound may be used individually and may use 2 or more types together.

As a method for supporting the active metal on the carrier, it can be carried out according to a known supporting method in this field. Examples of such a supporting method include an impregnation method, a coprecipitation method, an ion exchange method, and the like.

Water, methanol, ethanol, tetrahydrofuran, dioxane, hexane, benzene, toluene and the like are examples of the solvent for dissolving the raw material compound of the active metal used in the supporting method.

When the catalyst for producing butadiene contains two or more kinds of active metals, methods for supporting these active metals on the carrier include a simultaneous method, a sequential method, and the like. The simultaneous method is a method in which a solution in which all starting compounds are dissolved is supported on a carrier by the method described above. The sequential method is a method in which solutions are prepared by separately dissolving each raw material compound, and each solution is successively supported on the carrier by the method described above.

The support impregnated with the solution is calcined after being separated from the solution and dried. Thereby, the catalytically active element is immobilized on the carrier, and a catalyst can be obtained.
Separation of the carrier from the solution can be performed, for example, by filtration, decantation, centrifugation, or the like.
The drying temperature is preferably 20 to 200°C, more preferably 50 to 150°C. The drying time is preferably 1 hour to 10 days, more preferably 2 hours to 5 days.
The firing temperature is preferably 200 to 800°C, more preferably 400 to 600°C. The firing time is preferably 10 minutes to 2 days, more preferably 1 to 10 hours.

In the case of the sequential method described above, the second loading may be performed after performing the first loading and drying, or the second loading may be performed after performing the first loading, drying and firing. good.

≪Butadiene manufacturing equipment≫
The butadiene production apparatus of the present embodiment includes a reaction tube filled with the above-described butadiene production catalyst of the present embodiment.
A butadiene production apparatus produces butadiene from a raw material gas containing ethanol.

An example of a butadiene manufacturing apparatus will be described below with reference to FIG.
As shown in FIG. 1, a butadiene production apparatus 100 (hereinafter also simply referred to as "production apparatus 100") includes a reaction tube 1, a raw material supply pipe 3, a product discharge pipe 4, a temperature control unit 5, and a pressure control unit. 6, a first filter 7, a second filter 8, a third filter 9 and a fourth filter 10.
The reaction tube 1 has a catalyst layer 2 inside. The catalyst layer 2 contains the butadiene production catalyst of the present embodiment. A raw material supply pipe 3 is connected to the reaction tube 1 . A product discharge pipe 4 is connected to the reaction tube 1 . A temperature control unit 5 is connected to the reaction tube 1 . The product discharge pipe 4 is provided with a pressure control section 6 . The first to fourth filters may be installed in order from the lower end of the catalyst layer 2 inside the reaction tube 1 to any appropriate portion of the product discharge pipe. It is preferably located between the lower end of the catalyst layer 2 inside the and the connection portion of the product discharge pipe 4 . Moreover, it is more preferable that the first filter 7 be positioned at the connecting portion between the reaction tube 1 and the product discharge pipe 4 . A second filter 8 , a third filter 9 , and a fourth filter 10 are positioned in this order from the reactor side in the product discharge pipe 4 . The second filter 8, the third filter 9, and the fourth filter 10 may be installed vertically like the manufacturing apparatus 100 shown in FIG. 1, or may be installed in other directions. The installation direction of the filter depends on the direction of the installed product discharge pipe 4 . Above all, it is preferable that the second filter 8, the third filter 9, and the fourth filter 10 are installed vertically like the manufacturing apparatus 100 shown in FIG.

The catalyst layer 2 may have only the butadiene production catalyst of the present embodiment, or may have the butadiene production catalyst of the present embodiment and a diluent. The diluent prevents the catalyst from overheating.
The reaction to synthesize butadiene from a raw material containing ethanol is an endothermic reaction. Therefore, the catalyst layer 2 usually does not require a diluent.
The diluent is, for example, the same as the carrier for the catalyst for producing butadiene, quartz sand, alumina balls, aluminum balls, aluminum shot, or the like.
When the catalyst layer 2 is filled with a diluent, the mass ratio represented by the diluent/butadiene-producing catalyst is determined in consideration of the respective types and specific gravities, and is preferably 0.5 to 5, for example.
The catalyst layer may be of fixed bed, moving bed, fluidized bed or the like.

The reaction tube 1 is preferably made of a material inert to the raw material gas and the produced product. The reaction tube 1 preferably has a shape capable of withstanding heating at about 100 to 500° C. or pressure at about 10 MPa. The reaction tube 1 can be, for example, a substantially cylindrical member made of stainless steel.

The raw material supply pipe 3 is a supply means for supplying the raw material into the reaction tube 1 . The raw material supply pipe 3 is, for example, a pipe made of stainless steel.
The product discharge pipe 4 is discharge means for discharging gas containing the product produced in the catalyst layer 2 . The product discharge pipe 4 is, for example, a pipe made of stainless steel.

The temperature control unit 5 may be any unit as long as it can set the temperature of the catalyst layer 2 in the reaction tube 1 to an arbitrary temperature. The temperature control unit 5 is, for example, an electric furnace.
The pressure control unit 6 may be any device as long as it can set the pressure inside the reaction tube 1 to an arbitrary pressure. The pressure control unit 6 is, for example, a known pressure valve or the like.
In addition, the manufacturing apparatus 100 may be provided with well-known equipment such as a gas flow control unit for adjusting the flow rate of gas such as mass flow.

The mesh size of the first filter 7 is preferably 50% or less, more preferably 20 to 50%, even more preferably 30 to 50% of the average particle size of the catalyst for producing butadiene contained in the catalyst layer 2 . When the mesh size of the first filter 7 is equal to or less than the above upper limit, the catalyst for producing butadiene trapped in the first filter 7 can be reused. When the mesh size of the first filter 7 is equal to or larger than the above lower limit, pressure loss is less likely to occur, and production is stabilized.

The mesh size of the second filter 8 is preferably 25% or less, more preferably 10 to 25%, even more preferably 13 to 25%, of the average particle size of the butadiene production catalyst contained in the catalyst layer 2 . If the mesh size of the second filter 8 is equal to or less than the above upper limit, even when the catalyst is destroyed, it can be efficiently trapped. When the mesh size of the second filter 8 is equal to or larger than the above lower limit, pressure loss is less likely to occur, and production is stabilized.

The mesh size of the third filter 9 is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less of the average particle size of fragments when the catalyst for producing butadiene contained in the catalyst layer 2 is broken. . When the mesh size of the third filter 9 is equal to or less than the above upper limit, even when the catalyst is destroyed, it can be efficiently trapped. When the mesh size of the third filter 9 is equal to or larger than the above lower limit, pressure loss is less likely to occur, and production is stabilized.
The average particle size of the fragments when the catalyst for producing butadiene contained in the catalyst layer 2 is cracked is obtained by randomly selecting 50 fragments of the catalyst for producing butadiene, measuring the particle diameter of each of them, and calculating the value. can be obtained by averaging

The mesh size of the fourth filter 10 is preferably 1-400 μm, more preferably 5-300 μm, even more preferably 10-250 μm. When the mesh size of the fourth filter 10 is equal to or larger than the above lower limit, even the powdered catalyst can be trapped. When the mesh size of the fourth filter 10 is equal to or less than the above upper limit, pressure loss is less likely to occur, and production is stabilized.

When the mesh size of the second filter 8, the third filter 9 and the fourth filter 10 is 1-700 μm, high molecular weight by-products can be trapped. Therefore, the mesh size of the second filter 8 is preferably 1-700 μm. Similarly, the mesh size of the third filter 9 is preferably 1-700 μm. Similarly, the mesh size of the fourth filter 10 is preferably 1-700 μm.
High molecular weight by-products include, for example, δ-hexanolactone, 2,6-diisopropylphenol, and the like.

Since butadiene can be continuously produced, the product discharge pipe 4 preferably has two or more branches. Since the product discharge pipe 4 has branches, the second to fourth filters can be provided in the branched pipes to trap the above-mentioned by-products. Although the upper limit of the number of branches is not particularly limited, it is set to 10, for example.

The thickness of the second filter 8 is preferably 1 mm or more, for example. When the thickness of the second filter 8 is equal to or greater than the above lower limit, by-products can be efficiently trapped. Although the thickness of the second filter 8 is not particularly limited, it is, for example, 1 cm.
The thickness of the third filter 9 is similar to the thickness of the second filter 8 .
The thickness of the fourth filter 10 is similar to the thickness of the second filter 8 .

As used herein, the mesh size means the inner size of the openings in the mesh of the filter.

≪Butadiene production method≫
The method for producing butadiene of the present invention is a method for producing butadiene from a raw material containing ethanol using the catalyst for producing butadiene of the present embodiment. In the present embodiment, butadiene to be produced is not particularly limited, but 1,3-butadiene is preferred.

A method for producing butadiene using the above-described butadiene production apparatus 100 will be described below.
First, the temperature control unit 5 and the pressure control unit 6 are operated to set the inside of the reaction tube 1 to an arbitrary temperature and an arbitrary pressure.
Optional temperatures include, for example, 50 to 500.degree.
Arbitrary pressures include, for example, 0 to 1.0 MPaG.

Next, the gasified raw material is supplied into the reaction tube 1 from the raw material supply pipe 3 .
The feedstock is a substance that can be converted to butadiene and includes at least ethanol. The raw material is preferably ethanol, or ethanol and acetaldehyde, for example.
The method for producing butadiene of the present embodiment has a step of bringing a raw material containing ethanol into contact with the catalyst for producing butadiene of the present embodiment to produce butadiene (production step).
The manner in which the raw material is brought into contact with the butadiene-producing catalyst is not particularly limited. A mode of contacting the layer 2 with the raw material can be exemplified.

The raw material supplied into the reaction tube 1 flows through the catalyst layer 2, contacts with the butadiene production catalyst, and reacts.
Examples of the reaction temperature include 300 to 400°C.
Examples of the reaction pressure include 0 to 0.5 MPaG.

The gas hourly space velocity (GHSV) of the raw material with respect to the catalyst layer 2 containing the catalyst for producing butadiene is preferably 0.1 to 10000 h ^-1 , more preferably 100 to 5000 h ^-1 , and 200 in terms of standard conditions. ~4000 h ^-1 is more preferred, and 400 to 3000 h ^-1 is particularly preferred. When the GHSV is equal to or higher than the above lower limit, the processing capacity for raw materials containing ethanol increases. When the GHSV is equal to or less than the above upper limit, the yield of butadiene is improved.
The above GHSV is the GHSV of ethanol with respect to the volume of the butadiene production catalyst contained in the catalyst layer 2 when the raw material does not contain acetaldehyde, and the butadiene production catalyst contained in the catalyst layer 2 when the raw material contains acetaldehyde. means the GHSV of the sum of ethanol and aldehydes per volume of .
Hereinafter, in this specification, GHSV means a value in terms of standard conditions.

Butadiene is obtained from the reacted raw materials in the reaction tube 1 (production step). A product gas containing butadiene is discharged from the product discharge pipe 4 .

The generated gas may contain compounds such as acetaldehyde, propylene, and ethylene in addition to ethanol and butadiene.
The generated gas containing butadiene is subjected to purification such as gas-liquid separation and distillation purification as necessary to remove unreacted raw materials and by-products.

The catalyst inside the reaction tube 1 may be fixed inside the reaction tube 1 by a first filter 7 . In this case, fragments of the butadiene production catalyst discharged together with the generated gas are collected by the second filter 8, the third filter 9 and the fourth filter 10. FIG. When the catalyst in the reaction tube 1 is fixed, the second filter 8, the third filter 9, and the fourth filter 10 located downstream from the lower end of the catalyst layer 2 catch fragments of the catalyst. be collected. By installing a plurality of these filters, catalyst fragments can be collected step by step, and clogging of pipes can be prevented. Also, the number of the second to fourth filters may be one. That is, a configuration without the third filter 9 and the fourth filter 10 may be used.

The method for producing butadiene of the present embodiment may have a catalyst regeneration step.
The catalyst regeneration step is a step of bringing an oxygen-containing gas into contact with the butadiene-producing catalyst at a predetermined temperature to regenerate the butadiene-producing catalyst.
In the catalyst regeneration step, for example, a gas containing oxygen is supplied into the reaction tube 1 from the raw material supply pipe 3 . In the reaction tube 1, gas containing oxygen comes into contact with the catalyst for producing butadiene, the carbonaceous matter is burned, and the catalyst is regenerated.
The temperature inside the reaction tube 1 when regenerating the catalyst is, for example, 450 to 550.degree.
The pressure inside the reaction tube 1 when regenerating the catalyst is, for example, 0 to 10 MPaG.

The GHSV of the oxygen-containing gas with respect to the catalyst layer 2 containing the catalyst for producing butadiene is preferably 0.02 to 10000 h ^-1 , more preferably 20 to 5000 h ^-1 , further preferably 20 to 4000 h ^-1 in terms of oxygen, and 80 ˜3000 h ⁻¹ is particularly preferred. When the GHSV is equal to or higher than the above lower limit, catalyst regeneration proceeds favorably. When the GHSV is equal to or less than the above upper limit, heat generation during regeneration is suppressed, and deterioration of the catalyst for producing butadiene is easily suppressed.

Exhaust gas generated by combustion is discharged from the product discharge pipe 4 .
Fragments of the butadiene-producing catalyst discharged from the reaction tube together with the exhaust gas are collected by the first filter 7 , the second filter 8 , the third filter 9 and the fourth filter 10 .

According to the butadiene-producing catalyst of the present embodiment, since it has a specific average particle size and a specific average sphericity, the butadiene-producing catalysts are in point contact, not surface contact. Therefore, since the filling state tends to be uniform, it becomes difficult for the raw material to flow unevenly. Furthermore, adhesion between catalysts is also suppressed. As a result, variations in productivity of butadiene can be suppressed.
In addition, the catalyst for producing butadiene of the present embodiment has a specific average particle size and a specific average sphericity, so sticking between the pipe and the catalyst for producing butadiene is suppressed. Therefore, it becomes easy to wash the pipes when replacing the catalyst, and the maintainability is improved.

According to the catalyst for producing butadiene of the present embodiment, since it has a specific angle of repose, sufficient fluidity can be ensured, and the filling rate of the catalyst for producing butadiene in the reaction tube can be increased. Therefore, the production efficiency of butadiene can be further improved.

Since the butadiene-producing catalyst of the present embodiment has a specific crushing strength, the butadiene-producing catalyst is less likely to be broken, and the reaction tube and a portion of the piping subsequent to the reaction tube are less likely to be clogged. As a result, pressure loss and drift of the raw material are less likely to occur, and the production efficiency of butadiene is improved.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Production of catalyst for producing butadiene]
[Example 1]
First, 7 g of zirconium chloride oxide octahydrate (ZrCl ₂ O.8H ₂ O: manufactured by Kojundo Chemical Laboratory Co., Ltd.) and 0.014 g of hafnium chloride (HfCl ₄ : manufactured by Kojundo Chemical Laboratory Co., Ltd.) was dissolved in 200 mL of water to prepare a solution.
Next, this solution was added to 4.0 g of a porous carrier (silica porous particles manufactured by Fuji Silysia Chemical Co., Ltd., average particle size: 1.75 mm, average pore diameter: 10 nm, total pore volume: 1.01 mL /g, specific surface area: 283 m ² /g, average sphericity 0.93).
Next, the solution in which the porous carrier was immersed was stirred under atmospheric pressure with an ultrasonic cleaner for 3 hours, and then the solution was separated by filtration.
The recovered porous material was dried at 110° C. for 4 hours and then calcined at 400° C. for 4.5 hours to produce a catalyst.

[Example 2]
As a porous carrier, silica porous particles manufactured by Fuji Silysia Chemical Co., Ltd. (average particle size: 2.85 mm, average pore diameter: 10 nm, total pore volume: 1.01 mL / g, specific surface area: 283 m ² /g A catalyst was produced in the same manner as in Example 1, except that a carrier having an average sphericity of 0.89 was used.

[Example 3]
A catalyst was produced in the same manner as in Example 1, except that the calcination time was 8 hours.

[Comparative Example 1]
The same method as in Example 1 except that a support of cylindrical silica porous particles (column diameter 1.62 mm, average sphericity 0.34) manufactured by Fuji Silysia Chemical Co., Ltd. was used as the porous support. to prepare the catalyst.

[Comparative Example 2]
The same method as in Example 1, except that a columnar silica porous particle carrier manufactured by Fuji Silysia Chemical Co., Ltd. (column diameter: 3.61 mm, average sphericity: 0.77) was used as the porous carrier. to prepare the catalyst.
The following measurements and evaluations were performed on the obtained catalysts for producing butadiene of each example. The results are also shown in Table 1.

[Analysis of physical properties of catalyst for producing butadiene]
1. Measurement of Average Particle Size The particle size of the catalyst for producing butadiene was obtained by measuring the major diameter and minor diameter of the particles of the catalyst for producing butadiene with an optical microscope (manufactured by Keyence Corporation, Digital Microscope VHX-2000). The particle diameters of 50 randomly selected catalyst particles for butadiene production were obtained, and the average of them was taken as the average particle diameter.
2. Measurement of Average Sphericality The sphericity of the catalyst for producing butadiene was determined from the "major axis" and "minor axis" determined by the measurement of the average particle size. The sphericity of 50 randomly selected catalyst particles for producing butadiene was obtained, and the average of them was taken as the average sphericity.
3. Measurement of Angle of Repose A cylindrical auxiliary jig with an inner diameter of 5 cm was placed on a flat cylindrical pedestal (6 cm in diameter), and 30 g of a catalyst for producing butadiene was placed in the auxiliary jig. The auxiliary jig was moved vertically upward and removed from the pedestal. At this time, the angle (acute angle) formed between the horizontal plane on the pedestal and the slope of the mountain was measured with a protractor in a state in which the formed catalyst mountain for producing butadiene remained stable without spontaneously collapsing.
4. Measurement of average crushing strength The crushing strength of the catalyst for producing butadiene was measured according to JISZ8841:1993. The crushing strength of 50 randomly selected butadiene-producing catalyst particles was measured, and the average thereof was taken as the average crushing strength.

[Evaluation of fillability]
30 g of the catalyst for producing butadiene of each example was put into a 100 mL graduated cylinder placed vertically, and the height of the filling surface was measured (filling operation). When the filling operation is performed 10 times and the height of the filling surface is increased by 2% or more compared to the minimum value (minimum value of height among 10 times), it is regarded as "filling failure". counted the number of failures. Fillability was evaluated based on the following evaluation criteria. The smaller the number of filling failures, the better the filling properties.
"Evaluation criteria"
⊚: The number of filling failures is 0.
◯: The number of filling failures was 1.
Δ: The number of filling failures was 2.
x: The number of filling failures is 3 or more.

As shown in Table 1, in Examples 1 to 3 to which the present invention was applied, the number of filling failures was "0", indicating excellent filling properties.
On the other hand, in Comparative Example 1, in which the shape of the catalyst was not spherical, the number of filling failures was "3". In Comparative Example 2, in which the shape of the catalyst was not spherical, the number of filling failures was "4". This means that in Comparative Examples 1 and 2, the filling property is inferior, the flow rate of the raw material gas varies, and the productivity of butadiene varies.

According to the present invention, it was found that variations in productivity of butadiene can be suppressed.

REFERENCE SIGNS LIST 1 reaction tube 2 catalyst layer 3 raw material supply pipe 4 product discharge pipe 5 temperature control section 6 pressure control section 7 first filter 8 second filter 9 third filter 10 fourth filter 100 butadiene manufacturing apparatus

Claims (8)

A butadiene production catalyst used in a butadiene production method for producing butadiene from a raw material containing ethanol,
a group of spherical particles,
A catalyst for producing butadiene, having an average particle diameter of 1 to 8 mm and an average sphericity of 0.89 or more and 1 or less. 2. The catalyst for producing butadiene according to claim 1, which has an angle of repose of 20° or less. 3. The catalyst for producing butadiene according to claim 1, which has an average crushing strength of 10 to 150 [N]. A butadiene production apparatus comprising a reaction tube filled with the butadiene production catalyst according to any one of claims 1 to 3, a product discharge pipe, and a first filter,
The product discharge pipe is connected to the outlet of the reaction tube,
The first filter is located at a connection portion between the reaction tube and the product discharge pipe,
The apparatus for producing butadiene, wherein the mesh size of the first filter is 50% or less of the average particle size. further comprising a second filter,
The second filter is located downstream of the first filter in the product discharge pipe,
5. The apparatus for producing butadiene according to claim 4, wherein the mesh size of said second filter is 25% or less of said average particle diameter. further comprising a third filter,
The third filter is located downstream of the second filter in the product discharge pipe,
6. The apparatus for producing butadiene according to claim 5, wherein the mesh size of said third filter is 70% or less of the average particle diameter of fragments when said catalyst for producing butadiene is cracked. A method for producing butadiene, comprising the step of bringing a raw material containing ethanol into contact with the catalyst for producing butadiene according to any one of claims 1 to 3 to produce butadiene. A butadiene production method for producing butadiene from a raw material containing ethanol using the butadiene production apparatus according to any one of claims 4 to 6,
A method for producing butadiene, comprising a step of supplying the raw material to the reaction tube and bringing the raw material into contact with the catalyst for producing butadiene to produce butadiene.

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