JP5707841B2 - Method for producing fluidized bed catalyst and method for producing acrylonitrile - Google Patents

Description

  The present invention relates to a method for producing a fluidized bed catalyst containing iron and antimony, and a method for producing acrylonitrile.

  Iron and antimony-containing fluidized bed catalysts are widely known as catalysts suitable for the production of aldehydes and unsaturated acids by oxidation reactions of various organic compounds and the production of nitriles and hydrocyanic acids by ammoxidation reactions. In particular, the fluidized bed catalyst containing iron and antimony is useful for an ammoxidation reaction, and is used, for example, for producing acrylonitrile by an ammoxidation reaction of propylene, and for producing cyanuric acid by an ammoxidation reaction of methanol.

Conventionally, many studies have been made on catalysts used in oxidation reactions and ammoxidation reactions, and various catalysts have been proposed so far.
For example, Patent Document 1 discloses a composite oxide catalyst of antimony and at least one element selected from the group consisting of iron, cobalt, and nickel.
Since then, improvement of the catalyst has been energetically studied. For example, Patent Documents 2 to 11 disclose a catalyst obtained by adding tellurium, vanadium, tungsten, molybdenum, phosphorus or the like to iron or antimony.

Furthermore, investigations for improving the yield of the target product by improving the catalyst preparation method are continued.
For example, Patent Documents 12 to 16 disclose a method for adjusting the pH of a slurry containing antimony and a polyvalent metal compound, a method for heat-treating the slurry, and the like.
Patent Documents 17 and 18 disclose the particle size of an antimony compound used as a raw material when producing a catalyst containing antimony.

Japanese Examined Patent Publication No. 38-19111 Japanese Patent Publication No.46-2804 Japanese Patent Publication No. 47-19765 Japanese Patent Publication No. 47-19766 Japanese Patent Publication No.47-19767 JP 50-108219 A JP 58-145617 A JP-A-1-257125 JP-A-3-26342 JP-A-4-118051 JP 2001-114740 A Japanese Patent Publication No.47-18722 JP 49-40288 A Japanese Patent Laid-Open No. 52-140490 JP-A-60-137438 JP-A-1-265068 JP 58-11045 A JP-A 63-107745

However, although the catalysts disclosed in these patent documents have some effect in improving the yield of the target product, they are still not sufficient, and further improvements have been desired from an industrial standpoint. In particular, a fluidized bed catalyst that can produce acrylonitrile in high yield is desired.
In addition, further improvements in the physical properties of the catalyst required as a fluidized bed catalyst, such as the particle strength and fluidity of the resulting catalyst, have been desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a fluidized bed catalyst capable of producing a target product with high yield, having high particle strength, and excellent fluidity. And Another object of the present invention is to provide a method capable of producing acrylonitrile in a high yield by an oxidation reaction using a fluidized bed.

The method for producing a fluidized bed catalyst according to the present invention is a method for producing a fluidized bed catalyst containing iron and antimony represented by the following composition formula (I), wherein the solution or slurry contains at least raw materials of iron and antimony components. The step of adjusting the pH to 5 or less, the step of heat-treating the solution or slurry after pH adjustment at a temperature of 60 ° C. or higher, and the step of drying and baking the solution or slurry after heat treatment, Antimony trioxide powder having an average particle size of 0.51 μm or more and less than 5 μm is used as a raw material for the antimony component .
_{F e 10 Sb a A b Te} c D d E e O x · (SiO 2) y ··· (I)

Wherein Fe, Sb, Te, O and SiO ₂ represent iron, antimony, tellurium, oxygen and silica, respectively, A is at least one element selected from the group consisting of vanadium, molybdenum and tungsten, D is magnesium, Group consisting of calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, copper, silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic and bismuth And at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and a, b, c, d, e, x, and y are atomic ratios. A = 3-100, b = 0.1-5, c = 0 8, d = 0 to 50, e = 0 to 5, y = 10 to 200, and x is the number of oxygen atoms necessary to satisfy the valence of each component except silica.

Furthermore, the fluidized bed catalyst preferably contains iron antimonate as a crystal phase.
The acrylonitrile production method of the present invention is characterized in that acrylonitrile is produced in a fluidized bed in the presence of the fluidized bed catalyst produced by the fluidized bed catalyst production method.

According to the method for producing a fluidized bed catalyst of the present invention, it is possible to produce a target product with a high yield, and a fluidized bed catalyst having high particle strength and excellent fluidity.
Moreover, according to the manufacturing method of acrylonitrile of this invention, an acrylonitrile can be manufactured with a high yield by the oxidation reaction using a fluidized bed.

Hereinafter, the present invention will be described in detail.
[Production method of fluidized bed catalyst]
The method for producing a fluidized bed catalyst of the present invention is a method for producing a fluidized bed catalyst containing iron and antimony, the step of adjusting the pH of a solution or slurry containing at least iron and antimony component raw materials to 5 or less, It includes a step of heat-treating the solution or slurry after pH adjustment at a temperature of 60 ° C. or higher, and a step of drying and baking the solution or slurry after heat treatment, and the average particle size is 0. It is characterized by using an antimony trioxide powder that is 1 μm or more and less than 5 μm.

<Preparation process of solution or slurry>
In the catalyst manufacturing method of the present invention, first, a solution or slurry is prepared by mixing raw materials of components constituting a catalyst such as iron and antimony.
As a result of intensive studies, the present inventors have been able to produce the target product in high yield by using antimony trioxide powder having a specific particle size as a raw material for the antimony component in the solution or slurry preparation process, and The inventors have found that a fluidized bed catalyst having physical properties suitable as a fluidized bed catalyst can be produced, and have completed the present invention.

  That is, in the preparation step of the solution or slurry, antimony trioxide powder having an average particle size of 0.1 μm or more and less than 5 μm is used as a raw material for the antimony component. The lower limit of the particle size of the antimony trioxide powder is preferably 0.2 μm, and the upper limit is preferably 4 μm.

When the average particle size of the antimony trioxide powder used as a raw material for the antimony component is smaller than the lower limit, the selectivity of the desired product (for example, acrylonitrile) of the resulting catalyst is lowered. Further, the fluidity of the obtained catalyst is also deteriorated, which causes a problem when the catalyst is supplied to the reactor or when the catalyst is extracted from the reactor.
Furthermore, in catalyst production, since the oxidation reaction of antimony trioxide in the heat treatment process described later proceeds rapidly, it becomes difficult to control the reaction, the slurry bumps, or the slurry overflows from the preparation tank due to foaming, etc. May cause problems.

  On the other hand, when the average particle size of the antimony trioxide powder used as the raw material for the antimony component is larger than the above upper limit, the activity of the resulting catalyst and the selectivity of the target product are lowered. In addition, the particle strength of the obtained catalyst is reduced, and the catalyst is easily crushed in actual reaction use. As a result, there arises a problem that the catalyst scatters outside the reactor.

  When the average particle size of the antimony trioxide powder exceeds the above upper limit, it can be used after being pulverized by any method. However, since the effects of the present invention cannot be obtained when the particles are excessively pulverized and the average particle size of the antimony trioxide powder falls below the lower limit, it is preferable to pulverize while appropriately measuring the particle size.

The particle diameter of the antimony trioxide powder can be measured by any known method. Examples of measurement methods include BET method, laser diffraction method, dynamic light scattering method, centrifugal sedimentation method, electrical detector method, electron micrograph method and the like.
In addition, the particle diameter in this invention refers to the average particle diameter measured by BET method.

  On the other hand, the raw material of the iron component used in the preparation process of the solution or slurry is not particularly limited. For example, ferrous oxide, ferric oxide, ferrous nitrate, ferric nitrate, iron sulfate, iron chloride, iron Organic acid salts and iron hydroxide can be used, and metallic iron may be dissolved in heated nitric acid.

Moreover, the fluidized bed catalyst manufactured by the catalyst manufacturing method of this invention may contain other catalyst components other than iron and antimony.
When the catalyst contains other catalyst components, the raw materials for the other catalyst components include oxides of the catalyst components, or nitrates, carbonates, organic acid salts, ammonium salts that can be easily converted to oxides by ignition. , Hydroxides, heteropolyacids, heteropolyacid salts and the like can be used. Moreover, you may use these in combination of multiple types.

Moreover, since the catalyst manufactured by the catalyst manufacturing method of this invention is a fluidized bed catalyst, it is preferable to use a silica as a support | carrier.
As a raw material for the silica component, silica sol is preferable, which can be appropriately selected from commercially available ones.
The size of the silica particles in the silica sol is not particularly limited, but the average primary particle size is preferably 2 to 100 nm, more preferably 5 to 90 nm.
The silica sol may have a uniform silica particle size or may be a mixture of silica particles of several sizes. A plurality of types of silica sols having different average particle diameters and pH values may be mixed and used.

In the solution or slurry preparation step, the above-described raw material compounds are mixed with raw materials such as iron and antimony components in a solid, solution, or slurry state to obtain a solution or slurry.
The solution or slurry does not necessarily contain raw materials for all components constituting the catalyst, and these raw materials may be added in any step up to the drying step described later, or may be dried. Or you may add by the method of impregnating the catalyst after baking completion.

  In addition, in the preparation process of the solution or slurry, if the particle diameter of the antimony trioxide powder used as the raw material of the antimony component and the requirements relating to the pH adjustment process and the heat treatment process described later are satisfied, other requirements Is not particularly limited, and can be appropriately selected from known preparation methods.

<PH adjustment step>
Next, the pH of the solution or slurry containing at least iron and antimony is adjusted to 5 or less. Although there is no restriction | limiting in particular in the method of adjusting pH, Generally, the method of adding nitric acid, aqueous ammonia, etc. is used.

  The upper limit of the pH is preferably 4.5, more preferably 4. When the pH is higher than the upper limit, the oxidation reaction of antimony trioxide in the heat treatment step described later does not proceed sufficiently, and the activity of the resulting catalyst and the selectivity of the target product are lowered. Moreover, the particle | grain intensity | strength of the catalyst obtained also falls and the use as a fluid bed catalyst becomes difficult.

  The lower limit of the pH is not particularly limited, but if it is too low, it may cause a problem such as a slow oxidation reaction of antimony trioxide in the heat treatment step. Therefore, it is preferably 0.5, more preferably 1. is there.

<Heat treatment process>
Then, the solution or slurry after pH adjustment is heat-treated at a temperature of 60 ° C. or higher.
The lower limit of the heat treatment temperature is preferably 70 ° C, more preferably 80 ° C. When the temperature is lower than the lower limit, the oxidation reaction of antimony trioxide does not proceed or the reaction rate becomes extremely low, which is not practical. If the oxidation reaction of antimony trioxide does not proceed sufficiently, the activity of the resulting catalyst and the selectivity of the target product are reduced, and the particle strength of the catalyst is also reduced, making it difficult to use as a fluidized bed catalyst.

  The upper limit of the heat treatment temperature is not particularly limited, but it is generally carried out at a boiling point or lower, such as 120 ° C. or lower, at normal pressure of the solution or slurry after pH adjustment. If necessary, the treatment can be performed at a temperature of 120 ° C. or higher under pressure.

The lower limit of the heat treatment time is not particularly limited, but if the heat treatment time is too short, the oxidation reaction of antimony trioxide may not be completed, and the physical properties and activity of the resulting catalyst may be deteriorated. Is more preferable, and more preferably 1 hour.
The upper limit of the heat treatment time is not particularly limited, but it is usually within 10 hours because the performance of the catalyst obtained is not improved even if the treatment is performed for a longer time than necessary.

  The pressure during the heat treatment is not particularly limited, and may be appropriately selected in consideration of the properties of the solution or slurry to be heat treated, the heat treatment temperature, the specifications of the apparatus, and the like.

<Drying process>
Next, the solution or slurry after the heat treatment is dried. Thereby, a dried product (catalyst precursor) is obtained.
The drying method is not particularly limited and can be appropriately selected from known methods. However, since the catalyst produced by the catalyst production method of the present invention is a fluidized bed catalyst, spherical particles are obtained by spray drying. It is preferable that At the time of spray drying, a spray dryer such as a pressure nozzle type, a two-fluid nozzle type, or a rotary disk type is used.

At the time of spray drying, the temperature of the hot air flowing through the drying chamber of the spray dryer is preferably 130 ° C., more preferably 140 ° C., and the upper limit is preferably 400 ° C. near the inlet to the drying chamber. ° C, more preferably 380 ° C. The lower limit of the temperature in the vicinity of the drying chamber outlet is preferably 100 ° C., more preferably 110 ° C., and the upper limit is preferably 250 ° C., more preferably 230 ° C. Furthermore, the difference between the temperature near the inlet and the temperature near the drying chamber outlet is preferably maintained at 20 to 250 ° C, more preferably 30 to 230 ° C.
If each of the above temperatures is out of the predetermined range, problems such as reduction in the activity of the catalyst obtained and the yield of the target product, and reduction in bulk density and particle strength of the catalyst particles may occur. There is.

<Baking process>
Next, the dried product (catalyst precursor) is fired to obtain a fluidized bed catalyst containing iron and antimony. A desirable catalyst structure is formed by the calcination step, and the activity as a catalyst is expressed.
In the present invention, the firing is preferably carried out in two or more times. The target product yield may be improved by performing the firing in two or more steps.

  Assuming that the last firing is final firing and the firing performed prior to final firing is temporary firing, the lower limit of the final firing temperature is preferably 550 ° C, more preferably 570 ° C, and the upper limit is preferably 1100 ° C, more preferably Is 1000 ° C. When the final calcination temperature is lower than the lower limit, sufficient catalyst performance is not exhibited, and the target product yield may be reduced. Conversely, when it is higher than the upper limit, the target product yield and the activity of the catalyst may be lowered. Further, in the ammoxidation reaction, ammonia combustibility is remarkably increased, and the ammonia basic unit may be lowered, which is not preferable.

  The lower limit of the final firing time is preferably 0.1 hour, and more preferably 0.5 hour. When the calcination time is shorter than the lower limit, sufficient catalytic performance is not exhibited, and the target product yield may be reduced. The upper limit is not particularly limited, but the effect obtained even if the time is extended more than necessary is usually not more than a certain value, and is usually within 20 hours.

On the other hand, the lower limit of the pre-baking temperature is preferably 160 ° C., more preferably 180 ° C., and the upper limit is preferably 520 ° C., more preferably 500 ° C. Moreover, it is preferable that the temperature of temporary baking shall be 100-400 degreeC lower than the temperature of final baking.
The lower limit of the calcination time is preferably 0.1 hour, more preferably 0.5 hour. When the calcination time is shorter than the lower limit, sufficient catalytic performance is not exhibited, and the target product yield may be reduced. The upper limit is not particularly limited, but is usually within 20 hours because the effect obtained even if the time is extended more than necessary does not become a certain level.

A general-purpose firing furnace can be used for final firing and temporary firing. Since the catalyst produced by the catalyst production method of the present invention is a fluidized bed catalyst, a rotary kiln, a fluidized firing furnace or the like is particularly preferably used.
In addition, the gas atmosphere used in the final firing and the preliminary firing may be an oxidizing gas atmosphere containing oxygen or an inert gas atmosphere such as nitrogen, but it is convenient to use air.

  The particle size of the catalyst thus obtained is preferably in the range of 5 to 200 μm, more preferably in the range of 10 to 180 μm. In order to make the particle size distribution of the obtained catalyst within a desired range, the conditions of the drying process may be adjusted as appropriate.

The fluidized bed catalyst produced by the method for producing a catalyst of the present invention is not particularly limited as long as it contains iron and antimony, but a composition represented by the following general formula (I) is preferable.
_{Fe 10 Sb a A b Te c} D d E e O x · (SiO 2) y ··· (I)

In the general formula (I), Fe, Sb, Te, O, and SiO ₂ each represent iron, antimony, tellurium, oxygen, and silica, and A is at least one element selected from the group consisting of vanadium, molybdenum, and tungsten. , D is magnesium, calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, copper, silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic And at least one element selected from the group consisting of bismuth, E represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium and cesium.
A, b, c, d, e, x and y represent an atomic ratio, and the lower limit of a is preferably 3, more preferably 5, and the upper limit is preferably 100, more preferably 90. The lower limit of b is preferably 0.1, more preferably 0.2, and the upper limit is preferably 5, more preferably 4. The lower limit of c is 0, and the upper limit is preferably 8, and more preferably 6. The lower limit of d is 0, and the upper limit is preferably 50, more preferably 40. The lower limit of e is 0, and the upper limit is preferably 5, more preferably 4.5. The lower limit of y is preferably 10, more preferably 20, and the upper limit is 200, more preferably 180. x is the number of oxygen atoms necessary to satisfy the valence of each of the components excluding silica.

When the composition of the fluidized bed catalyst produced by the method for producing a catalyst of the present invention is outside the range of the general formula (I), the yield of the target product is lowered or the properties of the obtained catalyst are lowered. For example, the effects of the present invention may not be sufficiently exhibited.
In particular, when the fluidized bed catalyst produced according to the present invention is used for the production of acrylonitrile by the ammoxidation reaction of propylene, the lower limit of c is preferably 0.1 in the above general formula (I). More preferably, it is 3.

  In order to make the catalyst composition within the range of the general formula (I), for example, in each step from the preparation step of the solution or slurry to the drying step in the addition step of each catalyst raw material in the solution or slurry preparation step What is necessary is just to select the addition amount of the catalyst raw material to add suitably. In addition, when the catalyst is produced by a method such as impregnating the dried catalyst, the amount of the catalyst raw material added by impregnation or the like may be appropriately selected.

  The composition of the catalyst can be confirmed by conducting elemental analysis by ICP (inductively coupled radio frequency plasma) emission analysis, fluorescent X-ray analysis, atomic absorption analysis or the like. In the case where an extremely volatile element is not used, it may be calculated from the amount of each raw material used at the time of catalyst production.

The fluidized bed catalyst produced by the catalyst production method of the present invention preferably contains iron antimonate as a crystal phase. There are several compositions of iron antimonate (see, for example, JP-A-4-118051), but FeSbO ₄ is the most common, and the presence of the crystalline phase can be confirmed by X-ray diffraction. A method for producing a catalyst containing iron antimonate as a crystal phase can be selected from any known methods. For example, after adjusting the pH of a solution or aqueous slurry containing at least the iron and antimony components and nitrate ions to 5 or less, heat treatment may be performed at a temperature of 60 ° C. or higher.
In this specification, “iron antimonate” includes not only pure iron antimonate but also various elements dissolved therein.

  As described above, in the catalyst production method of the present invention, the particle size of the antimony trioxide powder used as the raw material for the antimony component is determined, and the pH of the solution or slurry containing iron and antimony is adjusted to 5 or less, By performing the heat treatment at a temperature of not lower than ° C., a catalyst capable of producing the target product with a high yield can be obtained. Further, a catalyst having high particle strength and excellent fluidity and having physical properties suitable as a fluidized bed catalyst can be obtained.

  The fluidized bed catalyst produced by the catalyst production method of the present invention can be suitably used for reactions in which a fluidized bed is used, for example, production of nitriles by an ammoxidation reaction of an organic compound. Among the ammoxidation reactions, it is suitable for the production of acrylonitrile by the ammoxidation reaction of propylene and the production of hydrogen cyanide by the ammoxidation reaction of methanol, and particularly when used for the production of acrylonitrile, a high acrylonitrile yield is obtained.

[Method for producing acrylonitrile]
The method for producing acrylonitrile of the present invention is a method for ammoxidizing an organic compound in a fluidized bed in the presence of a fluidized bed catalyst produced by the catalyst production method of the present invention.
Specifically, it can be carried out by filling a fluidized bed reactor with a fluidized bed catalyst and supplying a raw material gas containing a raw material organic compound, ammonia and oxygen to the catalyst layer.

Although it does not specifically limit as source gas, The source gas of the range whose organic compound / ammonia / oxygen is 1 / 1.0-2.0 / 1.0-5.0 (molar ratio) is preferable.
It is convenient to use air as the oxygen source. The source gas may be used after being diluted with an inert gas such as water vapor, nitrogen or carbon dioxide, saturated hydrocarbon or the like, or may be used with an increased oxygen concentration.
The reaction temperature of the ammoxidation reaction is preferably 370 to 500 ° C., and the reaction pressure is preferably within the range of normal pressure to 500 kPa.
The apparent contact time is preferably 0.1 to 20 seconds.

  In the acrylonitrile production method of the present invention, the fluidized bed catalyst produced by the catalyst production method of the present invention is used as the catalyst, so that acrylonitrile can be produced in high yield.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to an Example.
In the following examples and comparative examples, “parts” means parts by mass.
In addition, the composition of the catalyst obtained by the Example and the comparative example was calculated | required from the preparation amount of each raw material used for manufacture of a catalyst. Moreover, the particle diameter of the antimony trioxide powder used as a raw material was calculated | required by BET method.
Moreover, about the catalyst obtained by each Example and the comparative example, the activity test, the fluidity | liquidity of a catalyst, and mechanical strength were evaluated in the following way, respectively.

[Catalyst activity test]
In order to evaluate the activity of the catalyst, acrylonitrile was produced by ammoxidation of propylene in the following manner.
A fluidized bed reactor having an inner diameter of 55 mm and a height of 2000 mm of the catalyst fluidized part was filled with the catalyst so that the apparent contact time between the catalyst and the raw material gas was as shown in Table 2. The contact time in that case was calculated | required by the following formula.
Contact time (seconds) = apparent volume density based catalyst volume (mL) / feed gas amount converted to reaction conditions (mL / second)

Air is used as an oxygen source, and a raw material gas having a composition of propylene: ammonia: oxygen = 1: 1.1: 2.3 (molar ratio) is sent to the catalyst layer at a gas linear velocity of 17 cm / second (under a reaction atmosphere). I entered. The reaction pressure was 200 kPa, and the reaction temperature was 460 ° C.
Gas chromatography was used to quantify the reaction product, and the propylene conversion rate and acrylonitrile yield 4 hours after the start of the reaction were determined. The propylene conversion rate and acrylonitrile yield at that time were determined by the following formula.
Propylene conversion rate (%) = {(carbon mass of supplied propylene−carbon mass of unreacted propylene) / carbon mass of supplied propylene} × 100
Acrylonitrile yield (%) = (carbon mass of produced acrylonitrile / carbon mass of supplied propylene) × 100

[Evaluation of fluidity of catalyst]
About the catalyst which used for the activity test, the angle of repose was measured using the cylindrical rotation-type angle of repose measuring instrument (made by Tsutsui Riken Kikai Co., Ltd.).
Specifically, 150 mL of catalyst powder is placed in a glass cylindrical container having an outer diameter of 95 mm and a height of 75 mm, placed on the carriage of the angle of repose measuring instrument, and rotated for 5 minutes at 2 rpm, and then rotated. The angle of repose of the catalyst powder at that time was measured with the attached protractor. Subsequently, after rotating at 2 rpm for 1 minute, rotation was stopped and the angle of repose of the catalyst powder at that time was measured with a protractor. Thereafter, measurement by this method was repeated to obtain a total of 10 measurement values. The average value of these 10 measured values was taken as the angle of repose of the catalyst and used as an index of fluidity.

[Evaluation of mechanical strength of catalyst]
About 50 catalyst particles arbitrarily collected from the sieved 45-50 μm catalyst, each compressive strength was measured under the following measurement conditions using a compressive strength tester (“Shimadzu MCTM-200” manufactured by Shimadzu Corporation). The average value was taken as the compressive strength of the catalyst.
Upper pressure indenter: (500 μm flat indenter made of diamond)
Lower pressure plate: SUS plate Load speed: 7.1 mN / sec

[Example 1]
Catalysts having the compositions shown in Table 1 were prepared by the following procedure.
First, 104.3 parts of copper powder was dissolved in 3600 parts of 63% by mass nitric acid. After adding 3500 parts of pure water to this solution, the mixture was heated to 60 ° C., 305.5 parts of electrolytic iron powder and 83.8 parts of tellurium powder were successively added and dissolved (solution A).
Separately, a solution (solution B) in which 57.1 parts of ammonium paratungstate was dissolved in 1800 parts of pure water, a solution (solution C) in which 38.6 parts of ammonium paramolybdate was dissolved in 100 parts of pure water, 400 parts of pure water A solution (solution D) in which 125.6 parts of telluric acid was dissolved was prepared.
Next, 9860 parts of 20 mass% silica sol, 1993.5 parts of antimony trioxide powder having an average particle diameter of 0.51 μm, B liquid, and C liquid were sequentially added to the A liquid with stirring to obtain an aqueous slurry.
While continuing stirring, 15% by mass of aqueous ammonia was added dropwise to this aqueous slurry to adjust the pH to 2.2, and the resulting aqueous slurry was heated at 98 ° C. for 3 hours under reflux.
The aqueous slurry after the heat treatment was cooled to 80 ° C., and D solution, 190.9 parts of nickel nitrate, 18.9 parts of 85% by mass phosphoric acid, and 40.6 parts of boric acid were sequentially added.
The obtained aqueous slurry was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dried particles were calcined at 250 ° C. for 2 hours and at 450 ° C. for 2 hours, and finally fluidly calcined at 800 ° C. for 3 hours using a fluidized calcining furnace to obtain a catalyst.
The mechanical strength of the obtained catalyst was evaluated. Moreover, the activity test was implemented on the conditions shown in Table 2. Further, fluidity of the catalyst after the activity test was evaluated. The results are shown in Table 2.

[Example 2]
Catalysts having the compositions shown in Table 1 were prepared by the following procedure.
First, 47.4 parts of copper powder was dissolved in 4200 parts of 63% by mass nitric acid. After adding 4100 parts of pure water to this solution, the mixture was heated to 60 ° C., and 416.1 parts of electrolytic iron powder and 76.1 parts of tellurium powder were sequentially added and dissolved. Further, 229.2 parts of magnesium nitrate, 43.4 parts of cobalt nitrate, and 2.6 parts of lithium nitrate were sequentially added to this solution and dissolved (solution E).
Separately, a solution (solution F) in which 65.8 parts of ammonium paratungstate was dissolved in 1500 parts of pure water, a solution (solution G) in which 65.8 parts of ammonium paramolybdate were dissolved in 100 parts of pure water, 100 parts of pure water A solution (Liquid H) in which 8.7 parts of ammonium metavanadate was dissolved was prepared.
Next, with stirring, 8952 parts of 20 mass% silica sol, 2171.9 parts of antimony trioxide powder having an average particle size of 1.6 μm, F liquid, G liquid, and H liquid were sequentially added to E liquid to prepare an aqueous slurry. Obtained.
While continuing stirring, 15% by mass of aqueous ammonia was added dropwise to this aqueous slurry to adjust the pH to 2.5, and the resulting aqueous slurry was heat-treated at 99 ° C. for 4 hours under reflux.
The aqueous slurry after the heat treatment was cooled to 80 ° C., and 46.1 parts of boric acid was sequentially added.
The obtained aqueous slurry was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dried particles were calcined at 250 ° C. for 2 hours and 450 ° C. for 2 hours, and finally fluidly calcined at 770 ° C. for 3 hours using a fluidized calcining furnace to obtain a catalyst.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 3]
Catalysts having the compositions shown in Table 1 were prepared by the following procedure.
First, 74.2 parts of copper powder was dissolved in 1180 parts of 63% by mass nitric acid. After adding 1100 parts of pure water to this solution, it heated at 60 degreeC, 163.1 parts of electrolytic iron powder, and 111.8 parts of tellurium powder were added little by little one by one, and it melt | dissolved. Further, 23.4 parts of chromium nitrate, 25.1 parts of manganese nitrate, and 39.0 parts of zirconium oxynitrate were sequentially added to this solution and dissolved (solution I).
Next, 8770 parts of 20 mass% silica sol and 2553.2 parts of antimony trioxide powder having an average particle diameter of 2.1 μm were sequentially added to the liquid I while stirring to obtain an aqueous slurry.
While continuing stirring, 15% by mass of aqueous ammonia was added dropwise to the aqueous slurry to adjust the pH to 1.8, and the resulting aqueous slurry was heat-treated at 98 ° C. for 6 hours under reflux.
The aqueous slurry after the heat treatment was cooled to 80 ° C., and 94.8 parts of a 50 mass% metatungstic acid solution and 16.8 parts of 85 mass% phosphoric acid were sequentially added.
The obtained aqueous slurry was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dried particles were calcined at 250 ° C. for 2 hours and at 450 ° C. for 2 hours, and finally fluidly calcined at 800 ° C. for 3 hours using a fluidized calcining furnace to obtain a catalyst.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 4]
Catalysts having the compositions shown in Table 1 were prepared by the following procedure.
First, 72.6 parts of copper powder was dissolved in 1140 parts of 63% by mass nitric acid. After adding 1100 parts of pure water to this solution, it heated at 60 degreeC, 255.3 parts of electrolytic iron powder, and 87.5 parts of tellurium powder were added little by little, and it melt | dissolved (J liquid).
Separately, a solution (solution K) in which 47.7 parts of ammonium paratungstate was dissolved in 1000 parts of pure water and a solution (solution L) in which 24.2 parts of ammonium paramolybdate were dissolved in 50 parts of pure water were prepared.
Next, with stirring, 10986 parts by weight of 20 mass% silica sol, 998.9 parts of antimony trioxide powder having an average particle size of 1.0 μm, liquid K and liquid L were sequentially added to liquid J to obtain an aqueous slurry.
While continuing stirring, 15% by mass of ammonia water was added dropwise to the aqueous slurry to adjust the pH to 2.0, and the resulting aqueous slurry was heat-treated at 98 ° C. for 3 hours under reflux.
The aqueous slurry after the heat treatment was cooled to 80 ° C., and 106.3 parts of nickel nitrate, 68.0 parts of zinc nitrate, 21.1 parts of 85 mass% phosphoric acid, and 14.1 parts of boric acid were sequentially added.
The obtained aqueous slurry was spray-dried with a spray dryer at a drying air temperature of 330 ° C. at the dryer inlet and 160 ° C. at the dryer outlet to obtain spherical dry particles. Next, the obtained dried particles were calcined at 250 ° C. for 2 hours and at 450 ° C. for 2 hours, and finally fluidly calcined at 780 ° C. for 3 hours using a fluidized calciner to obtain a catalyst.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
A catalyst having the same composition as in Example 1 was prepared in the same manner as in Example 1.
However, antimony trioxide having an average particle size of 11.0 μm was used as a raw material for the antimony component.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 2]
A catalyst having the same composition as in Example 1 was prepared in the same manner as in Example 1.
However, antimony trioxide having an average particle size of 8.2 μm was used as a raw material for the antimony component.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 3]
A catalyst having the same composition as in Example 4 was prepared in the same manner as in Example 4.
However, antimony trioxide having an average particle size of 0.02 μm was used as a raw material for the antimony component.
In the catalyst production, the foam was vigorously foamed in the heat treatment step, and a marked rise in the liquid level was observed.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 4]
A catalyst having the same composition as in Example 4 was produced in the same manner as in Example 4.
However, heat treatment was not performed, and after adjusting the pH of the aqueous slurry to 2.0, nickel nitrate, zinc nitrate, 85 mass% phosphoric acid, and boric acid were sequentially added.
The obtained catalyst was evaluated in the same manner as in Example 1. The results are shown in Table 2.

As is clear from Table 2, all of the fluidized bed catalysts obtained in Examples 1 to 4 were able to produce acrylonitrile in a high yield. Moreover, it had high mechanical strength, excellent fluidity, and had the physical properties required for a fluidized bed catalyst.
On the other hand, although the fluidized bed catalysts obtained in Comparative Examples 1 and 2 had the same composition as the fluidized bed catalyst obtained in Example 1, the yield of acrylonitrile was lower than that in Example 1. . Further, the mechanical strength of the catalyst was low.
Although the fluidized bed catalyst obtained in Comparative Example 3 has the same composition as the fluidized bed catalyst obtained in Example 4, the yield of acrylonitrile is lower than that in Example 4, and the fluidity Was also inferior.
Although the fluidized bed catalyst obtained in Comparative Example 4 has the same composition as the fluidized bed catalyst obtained in Example 4, the propylene conversion rate and the acrylonitrile yield are significantly lower than those in Example 4. Also, the fluidity and mechanical strength were extremely low.

Claims (3)

A method for producing a fluidized bed catalyst containing iron and antimony represented by the following composition formula (I) :
A step of adjusting the pH of a solution or slurry containing at least iron and antimony component raw materials to 5 or less, a step of heat-treating the solution or slurry after pH adjustment at a temperature of 60 ° C. or higher, and a solution or slurry after the heat treatment Drying and firing,
A method for producing a fluidized bed catalyst, wherein an antimony trioxide powder having an average particle size of 0.51 μm or more and less than 5 μm is used as a raw material for the antimony component.
_{Fe 10 Sb a A b Te c} D d E e O x · (SiO 2) y ··· (I)
(Wherein Fe, Sb, Te, O and SiO ₂ represent iron, antimony, tellurium, oxygen and silica, respectively, A is at least one element selected from the group consisting of vanadium, molybdenum and tungsten, and D is magnesium. , Calcium, strontium, barium, titanium, zirconium, niobium, chromium, manganese, cobalt, nickel, copper, silver, zinc, boron, aluminum, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic and bismuth At least one element selected from the group, E represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium and cesium, and a, b, c, d, e, x and y are atoms. The ratio, a = 3-100, b = 0.1-5, c = 0 -8, d = 0 to 50, e = 0 to 5, y = 10 to 200, and x is the number of oxygen atoms necessary to satisfy the valence of each of the above components excluding silica.) The method for producing a fluidized bed catalyst according to claim 1, wherein the fluidized bed catalyst contains iron antimonate as a crystal phase. The presence of a fluid bed catalyst produced by the production method of the fluidized bed catalyst according to claim 1 or 2, the manufacturing method of acrylonitrile, characterized by producing acrylonitrile by fluidized bed.