JP6207346B2 - Method for cleaning supported treatment apparatus, method for producing unsaturated aldehyde and unsaturated carboxylic acid production catalyst having washing step by the washing method, catalyst therefor, and method for producing unsaturated aldehyde and unsaturated carboxylic acid - Google Patents

Description

  The present invention relates to catalytic gas phase oxidation of a gas containing at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether in the presence of molecular oxygen or molecular oxygen-containing gas. A method for cleaning a supported treatment apparatus in a manufacturing process of a catalyst for manufacturing a corresponding unsaturated aldehyde and unsaturated carboxylic acid, a manufacturing method of a catalyst having a cleaning process by the cleaning method, the catalyst, and the method The present invention relates to a method for producing an unsaturated aldehyde and an unsaturated carboxylic acid using the produced catalyst.

  Catalytic gas phase oxidation of a gas containing at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether in the presence of molecular oxygen or molecular oxygen-containing gas, As a method for producing a catalyst for efficiently producing a corresponding unsaturated aldehyde and unsaturated carboxylic acid, many proposals for supporting a catalytically active component on an inert carrier have been made.

For example, a catalyst raw material powder containing molybdenum, iron, and bismuth is put into a centrifugal fluidized coating apparatus, granulated to have an average diameter of 2 to 10 mm, and then fired to have a specific surface area of 5 to ²⁰ m ^2. / G, the pore volume is in the range of 0.3 to 0.9 cc / g, and the pore diameter distribution is concentrated in the range of 1 to 10 μm and 0.1 to 0.9 μm, respectively. (Patent document 1) which obtains the catalyst which has the distribution which carried out, the inorganic fiber which contains molybdenum and bismuth as a catalyst active component, and whose average diameter is the range of 2-200 micrometers is 0.5-50 with respect to a catalyst active substance A method of using as a supporting auxiliary material in the range of% by weight (Patent Document 2), a catalyst in which a catalytically active component is supported on an inert carrier, wherein the average particle size of the catalyst is 4 to 16 mm, and the average particle size of the carrier is A catalyst having a calcination temperature of 500 to 600 ° C., a supported amount of the catalytically active component on the support of 5 to 80 wt% (Patent Document 3), a catalytically active component and an inert carrier in a supported treatment apparatus used in the supported treatment step And a catalyst is obtained by controlling the supply amount (volume basis) of the catalytically active component to a range of 1 to 10 times per hour with respect to the capacity of the loaded processing apparatus (Patent Document 4) Etc. are disclosed.

Japanese Patent Laid-Open No. 63-200839 Japanese Patent Laid-Open No. 6-381 JP-A-10-28877 JP 2012-45516 A

  However, further improvement is desired regarding the improvement of the productivity in the production process of the catalyst and the stability of the physical properties and performance of the obtained catalyst.

  The production of unsaturated aldehydes and unsaturated carboxylic acids on an industrial scale usually requires a large amount of catalyst, from several tons to tens of tons per reactor.

  In the production of the catalyst, the catalyst is generally produced by a supporting treatment in which a catalytically active component is supported on a carrier. When a catalyst is produced using a supporting treatment device, the granular catalytically active component is usually supplied to a container portion (hereinafter also referred to as “pan”) that drives the supporting treatment.

  However, as described above, in order to produce a large amount of catalyst, it is necessary to repeatedly carry the supporting process, and the amount of the catalyst active component fixed and deposited in the pan increases as the supporting process time or the number of the supporting processes increases. Further, even when a continuous supporting process as described in Patent Document 4 is performed, a long supporting process is required to produce a large amount of catalyst, and as the supporting process time increases, Increases the amount of sticking / depositing of the catalytically active component.

  For this reason, it is necessary to wash the inside of the pan after every fixed loading treatment. If the washing treatment is not performed or if the washing treatment is insufficient, the lumps of the catalytically active components fixed in the pan are peeled off and the product is removed. As a result, it not only deteriorates the physical properties of the catalyst such as the particle size, mechanical strength, and bulk density of the resulting catalyst, but also decreases the catalyst performance such as the activity and selectivity of the target product.

  In addition, since the catalytically active component is firmly fixed in the pan, manual water washing by the worker takes a lot of time, and there is a problem that the productivity of the catalyst is reduced. The physical and mental distress is also great. Furthermore, since a large amount of waste water is generated, it is not preferable for the environment, and a great deal of labor and energy is consumed to treat the waste water.

  Thus, an object of the present invention is to provide an efficient loading treatment apparatus washing method that solves the above problems, and a catalyst production method having excellent reproducibility with little change in catalyst physical properties and catalyst performance having the washing treatment step. There is.

  In order to solve such problems, the present inventors have included a molecular oxygen or a molecular oxygen-containing gas containing at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether. As a result of earnestly examining the cleaning method of the supporting treatment apparatus in the production process of the catalyst for producing the corresponding unsaturated aldehyde and unsaturated carboxylic acid by catalytic gas phase oxidation in the presence of gas, the supporting treatment apparatus The inside of the pan is washed by injecting the inorganic material into the pan, that is, the inside of the pan is physically washed with the inorganic material, so that waste water can be reduced and the inside of the pan after the carrying treatment is fixed. The present inventors have found that the catalytically active component can be easily removed and the production efficiency can be increased, and the present invention has been achieved.

  Furthermore, the inventors have found that a stable catalyst with little change in catalyst physical properties and catalyst performance can be produced by using the above-described cleaning method as a cleaning method for the supporting treatment apparatus, and the present invention has been achieved.

  According to the present invention, a corresponding unsaturated aldehyde is obtained by catalytic gas phase oxidation using at least one compound selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether as a raw material in the presence of molecular oxygen. In the washing of a supported treatment apparatus used for the production of a catalyst for producing an unsaturated carboxylic acid, the amount of waste water can be reduced and the fixed catalytic active component can be easily removed, and the production efficiency of the catalyst can be increased. .

  Further, by using the washing method as a washing method for the supporting treatment apparatus, a stable catalyst with little change in catalyst physical properties and catalyst performance can be produced.

  Hereinafter, the present invention will be described in detail. However, the scope of the present invention is not limited to the following description, and can be appropriately modified and implemented without departing from the spirit of the present invention.

  In the method for cleaning a supported processing apparatus according to the present invention, the inside of the pan is cleaned by operating by putting an inorganic substance into the pan of the supported processing apparatus, that is, the inside of the pan where the catalytically active component is fixed after the supporting process. May be physically washed with an inorganic substance. By operating by putting an inorganic substance in the pan, the catalytically active component fixed by the dead weight and rotation of the inorganic substance can be efficiently scraped off and removed.

  In addition, the cleaning treatment with the inorganic material may be performed after the supporting treatment is performed for a certain period. For example, the accumulated time of the supporting treatment is within 24 hours, preferably within 12 hours, more preferably within 8 hours. The cleaning process may be performed once or more.

  The material of the inorganic material that can be used in the present invention is not particularly limited, and is made of metal such as copper, iron, stainless steel, alumina, silica, silica-alumina, titania, magnesia, mullite, steatite, cordierite, silica-magnesia, Although those made of ceramics such as silicon carbide, silicon nitride, and zeolite can be used, those made of metal are preferred, and stainless steel (made of SUS) is particularly preferred.

  The shape of the inorganic material that can be used in the present invention is not particularly limited, and at least one shape selected from the group consisting of a spherical shape, a star shape, a ring shape, a tablet shape, a pellet shape, and an amorphous shape can be used, but preferably Is in the form of a ring, pellet, or amorphous. As the shape, the longest distance d between two arbitrary ends is 1 mm ≦ d ≦ 30 mm, preferably 2 mm ≦ d ≦ 15 mm, and more preferably 2 mm ≦ d ≦ 10 mm. Here, the longest distance between two arbitrary ends is a distance between two points at which the linear distance is longest in the projection drawing of the inorganic substance. That is, if it is spherical, it corresponds to the diameter, and if it is ring-shaped or pellet-shaped, it corresponds to the diagonal line of the side projection (rectangle).

  A conventionally known apparatus can be used as the supporting treatment apparatus that can be used in the present invention. For example, the centrifugal fluid coating apparatus described in Patent Document 1, the rolling granulator described in Patent Document 3, and Special Table 2004 -Rocking mixer described in Japanese Patent No. 515337. Among these, a rolling granulator is preferable from the viewpoint of the device scale and ease of handling.

  Conditions for washing with inorganic materials are not particularly limited as long as the washing treatment has an effect. For example, in the case of a rolling granulator, the angle of the pan central axis with respect to the horizontal plane is inclined at 30 ° to 60 °. 20 to 90%, preferably 50 to 90% of the bread capacity is charged into the pan, and the operation is performed at 5 to 30 rpm, preferably 5 to 20 rpm for 5 to 60 minutes, preferably 10 to 30 minutes. That's fine. Here, the pan capacity is equal to the volume of water entering the tilted pan when the pan is used with a certain tilt angle. Moreover, the location to be cleaned can be adjusted to some extent by changing the inclination angle of the pan.

  When the catalytically active component is firmly fixed, a higher cleaning effect can be obtained by increasing the number of rotations of the pan and / or adding 5 to 50% of water or hot water. After completion of the washing treatment, the inorganic substance and the catalytically active component that has been peeled off are discharged from the pan, but the inorganic substance may be used repeatedly. In that case, the inorganic substance and the peeled catalytically active component may be separated using a sieve or a net, and the method is not particularly limited.

The catalyst for producing an unsaturated aldehyde and / or unsaturated carboxylic acid obtained by supporting the catalytic active component in the present invention on a carrier is represented by the following general formula (1) as a catalytic active component containing molybdenum, bismuth and iron. The composite oxide is preferably used.
_{Mo 12 Bi a Fe b A c} B d C e D f O x (1)
(Where Mo is molybdenum, Bi is bismuth, Fe is iron, A is at least one element selected from the group consisting of cobalt and nickel, and B is selected from the group consisting of alkali metals, alkaline earth metals and thallium. At least one element, C is at least one element selected from the group consisting of tungsten, silicon, aluminum, zirconium and titanium, D is phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron And at least one element selected from the group consisting of zinc, O is oxygen, and a, b, c, d, e, f, and x are atoms of Bi, Fe, A, B, C, D, and O, respectively. 0 <a ≦ 10, 0 <b ≦ 20, 2 ≦ c ≦ 20, 0 ≦ d ≦ 10, 0 ≦ e ≦ 30, 0 ≦ f ≦ 4, and x is each Is a value determined by oxidation states of the element.)

  The production method of the catalyst for producing an unsaturated aldehyde and / or unsaturated carboxylic acid obtained by carrying the catalytically active component on the carrier in the present invention, except that it has a step of washing the carrying treatment apparatus by the washing method described above. It can be produced according to a method generally used for preparing known unsaturated aldehyde and unsaturated carboxylic acid production catalysts.

Specifically, as a raw material of the catalyst component represented by the general formula (1), oxides, hydroxides, ammonium salts, nitrates, carbonates, sulfates, organic acid salts and the like of each component element, and the like An aqueous solution, a sol or the like, or a compound containing a plurality of elements is mixed with water to form an aqueous solution or an aqueous slurry (hereinafter sometimes referred to as “starting raw material mixture”).
Next, if necessary, the obtained starting material mixture is dried by various methods such as heating and decompression to obtain a catalytically active component precursor. Examples of the method for obtaining a catalytically active component precursor by drying by heating include, for example, a method of concentrating the starting raw material mixture and evaporating to dryness to obtain a cake-like catalytically active component precursor, spray dryer, drum dryer, rotary kiln. And the like, and a method of obtaining a block-like or flake-like catalyst active component precursor by heating in a gas stream using a box-type dryer, a tunnel-type dryer, etc. .

  The cake-like solid obtained by concentrating the starting raw material mixture and evaporating to dryness is further heat-treated in a stream of air using a box-type dryer, tunnel-type dryer, etc. A method for obtaining a catalyst active component precursor in the form of a catalyst can also be employed. Examples of a method for obtaining a solid catalyst active component precursor by drying under reduced pressure in the primary drying step include, for example, a method for obtaining a block or powdery catalyst active component precursor using a vacuum dryer. Can be mentioned.

  Further, the solid obtained by the primary drying step can be subsequently fired to make it a catalyst active component precursor. The obtained catalytically active component precursor is sent to a subsequent supporting step through a pulverization step and a classification step for obtaining a powder having an appropriate particle size as required. The particle size of the catalyst active component precursor is not particularly limited, but is in the range of 0.1 to 500 μm, preferably in the range of 10 to 300 μm, in order to maintain good supportability.

  Examples of the carrier for supporting the catalytic active component precursor include alumina, silica, silica-alumina, titania, magnesia, steatite, cordierite, silica-magnesia, silicon carbide, silicon nitride, zeolite, and the like. There is no restriction | limiting in particular also about the shape, Well-known shapes, such as spherical shape, ring shape, pellet shape, and an indefinite shape, can be used.

  The supporting treatment step can be performed by a conventionally known method. For example, a fixed amount of carrier and a fixed amount of catalytically active component powder are charged into a supporting treatment apparatus and supported. Examples thereof include a batch system in which the catalyst obtained each time is taken out from the apparatus, and a system in which the supporting treatment is continuously performed as described in Patent Document 4.

  Moreover, in order to improve a carrying state, a carrying auxiliary agent, a binder, etc. can be used. Specific examples include organic compounds such as ethylene glycol, glycerin, propionic acid, maleic acid, benzyl alcohol, propyl alcohol, butyl alcohol or phenols, water, nitric acid, ammonium nitrate, and ammonium carbonate. These supporting aids may be supplied to the carrier before supporting by spraying or impregnation in advance, or may be supplied by spraying or spraying into the pan during the supporting process, or a combination of both. Good. In addition, inorganic fibers may be added for the purpose of improving the mechanical strength of the catalyst, and pore forming agents may be added for the purpose of forming appropriate pores in the catalyst. The inorganic fiber is not particularly limited, and glass fiber, ceramic fiber, metal fiber, mineral fiber, carbon fiber, and the like can be used. The addition method can be added to the starting mixed solution or the catalyst active component precursor. Any method may be used as long as it can be uniformly dispersed or contained in the catalytically active component, such as mixing the inorganic fiber with the inorganic fiber. The pore forming agent is not particularly limited, and starch, cellulose, urea, polyvinyl alcohol, melamine cyanurate and the like can be used. Furthermore, it is possible to disperse or dissolve in a supporting aid or a binder and use them together.

  Here, as described above, from the viewpoint of fixing the catalytically active component to the support processing apparatus, after the support process is performed for a certain period, the support processing apparatus may be cleaned. It is not always necessary to perform the cleaning step at every batch processing or at a short time interval, and the accumulated time for carrying the supporting treatment is within 20 hours, preferably within 10 hours, more preferably within 7 hours at one or more intervals. What is necessary is just to perform the above-mentioned washing process.

The carrier obtained in the supporting step is sent to a subsequent firing step as necessary. The firing temperature is 350 ° C to 600 ° C, preferably 400 ° C to 550 ° C, more preferably 420 ° C to 500 ° C, and the firing time is preferably 1 to 10 hours. The firing atmosphere may be an oxidizing atmosphere, but a molecular oxygen-containing gas atmosphere is preferable, and it is particularly preferable to perform the firing step under the flow of the molecular oxygen-containing gas. Air is suitably used as the molecular oxygen-containing gas. Further, it may be dried once before the calcination step, and as described above, in the case of using the preliminarily calcined catalyst component particles for supporting, it is not always necessary to calcinate, and only drying may be performed. In addition, there is no restriction | limiting in particular as a baking furnace used for a baking process, What is necessary is just to use the box-type baking furnace or tunnel type baking furnace etc. which are generally used.

  In addition, you may provide a sieving process after the said carrying | support process or the said baking process as needed. When sieving is carried out after the supporting step, the supporting material that does not satisfy the desired supporting rate or particle size that has been sieved is supported separately so that the desired supporting rate or particle size can be obtained even after recycling to the supporting step. It may be processed. There is no limitation in particular as a sieving apparatus, For example, a net sieve, a punching metal, a specific gravity sorter, a roller-type sorter etc. can be used, and two or more apparatuses may be combined.

  Regarding the reactor used for producing unsaturated aldehydes and unsaturated carboxylic acids by catalytic gas phase oxidation of propylene, isobutylene or tertiary butyl alcohol with molecular oxygen in the present invention, a fixed bed reactor is used. Although there is no particular limitation as long as it is fixed, a fixed bed multitubular reactor is preferred. The inner diameter of the reaction tube is usually 15 to 50 mm, more preferably 20 to 40 mm, and still more preferably 22 to 38 mm.

  Each reaction tube of the fixed-bed multitubular reactor does not necessarily need to be filled with a single catalyst, and each layer is composed of a plurality of known types of catalysts (hereinafter sometimes referred to as “reaction zone”). It is also possible to fill in such a manner. For example, a method of filling catalysts having different loading rates from the raw material gas inlet side to the outlet side so as to increase the loading rate, a method of diluting a part of the catalyst with an inert carrier, or a method of combining them. It may be adopted. At this time, the number of reaction zones is appropriately determined depending on the reaction conditions and the scale of the reactor. However, if the number of reaction zones is too large, problems such as complicated packing of the catalyst occur. Is preferably about 2 to 6.

  There are no particular limitations on the reaction conditions in the present invention, and any of the conditions generally used for this type of reaction can be implemented. For example, the raw material gas is 1 to 15% by volume, preferably 4 to 12% by volume of propylene, isobutylene or tertiary butyl alcohol, 0.5 to 25% by volume, preferably 2 to 20% by volume of molecular oxygen, 0 to 30 to 5% by volume, preferably 0 to 25% by volume of water vapor, with the balance being an inert gas such as nitrogen at a temperature of 250 to 450 ° C. under a pressure of 0.1 to 1.0 MPa, 300 to 5, The catalyst may be contacted at a space velocity of 000 Hr-1 (standard state).

  The grade as the reaction raw material gas is not particularly limited. For example, when propylene is used as the raw material, polymer grade or chemical grade propylene can be used. Also, a propylene-containing mixed gas obtained by propane oxidative dehydrogenation reaction can be used. If necessary, air or oxygen can be added to this mixed gas.

[Example]
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Hereinafter, for convenience, “parts by mass” may be simply referred to as “parts”. Moreover, the conversion rate, selectivity, and yield in Examples and Comparative Examples were obtained by the following formulas.
Conversion rate [mol%]
= (Mol number of reacted starting material) / (mol number of supplied starting material) x 100
Selectivity [mol%]
= (Total number of moles of generated unsaturated aldehyde and generated unsaturated carboxylic acid) / (Number of moles of reacted starting material) x 100
Yield [mol%]
= (Total number of moles of unsaturated aldehyde produced and unsaturated carboxylic acid produced) / (Number of moles of supplied starting material) x 100
[Bulk specific gravity of catalyst]
The bulk specific gravity (g / ml) is calculated from the volume and mass of the catalyst filled in the graduated cylinder when the 100ml graduated cylinder is filled with the catalyst and tapped until there is no change in the volume on the rubber cushion. Asked.

[Measuring mechanical strength of catalyst]
A stainless steel reaction tube having an inner diameter of 25 mm and a length of 5000 mm is installed in the vertical direction, and the lower end of the reaction tube is closed with a stainless steel receiving plate having a thickness of 1 mm. About 50 g of the catalyst is dropped into the reaction tube from the upper end of the reaction tube, the stainless steel receiving plate at the lower end of the reaction tube is removed, and the catalyst is gently extracted from the reaction tube. The extracted catalyst was sieved with a sieve having an opening of 5 mm, and the mass of the catalyst remaining on the sieve was weighed.
Mechanical strength of catalyst [mass%]
= Mass of catalyst remaining on sieve / mass of catalyst dropped from top of reaction tube x 100

[Reference Example 1]
1000 parts of ammonium paramolybdate, 2.4 parts of potassium nitrate, and 425 parts of 20% by mass silica sol were dissolved in 3800 parts of distilled water (solution A). Further, 50 parts of 60% by weight nitric acid was added to 600 parts of distilled water, and 275 parts of bismuth nitrate, 824 parts of cobalt nitrate, 267 parts of iron nitrate and 288 parts of nickel nitrate were dissolved (Liquid B). B liquid was added to the prepared A liquid, and stirring was continued for 1 hour to obtain a slurry. The obtained slurry was heated and stirred to obtain a cake-like solid, and the obtained solid was dried at 220 ° C. for about 3 hours in an air atmosphere to obtain a dried product. The obtained dried product was pulverized to 500 μm or less to obtain a powder of a catalytically active component precursor. About 55 kg of a silica-alumina spherical carrier having an average particle size of 4.0 mm was charged into a rolling granulator having a diameter of 1.3 m, a weir height of 400 mm, and an inclination angle of 45 °. While rotating at a rotational speed of 15 rpm, the catalyst component precursor powder was continuously charged at a supply rate of 0.35 m ³ / h while spraying a 20% by mass aqueous ammonium nitrate solution as a binder. Under this condition, the supporting treatment was continuously performed for about 5 hours. The obtained carrier was sorted using a specific gravity sorter and then calcined at 470 ° C. for about 6 hours in an air atmosphere to obtain Catalyst 1. The catalyst 1 was supported at a rate of about 110% by mass, the yield was about 93% by mass, and the metal element composition excluding oxygen was as follows. The physical properties of the catalyst 1 are shown in Table 1.

Catalyst 1: Mo ₁₂ Bi _1.2 Co _6.0 Ni _2.1 Fe _1.4 Si _3.0 K _0.05
The loading rate and the yield were determined by the following formula.
Loading rate [mass%]
= (Mass of catalyst obtained-mass of carrier used) / mass of carrier used x 100
Yield [mass%]
= Mass of the obtained support / (mass of the catalytically active component used + mass of the carrier used) × 100

[Reactor]
A reactor composed of a stainless steel reaction tube having a total length of 3000 m and an inner diameter of 25 mm and a shell for flowing a heat medium covering the same is prepared in the vertical direction, the catalyst 1 obtained from the upper part of the reaction tube is dropped, and the layer length is 2750 mm. It filled so that it might become.

[Oxidation reaction]
From the lower part of the reactor, a mixed gas composed of 7.5% by volume of propylene, 14% by volume of oxygen, 6% by volume of water vapor and the balance of an inert gas component such as nitrogen is introduced at a space velocity of 1900 hr ⁻¹ (standard state). The propylene oxidation reaction was carried out at a heat medium temperature of 315 ° C. The results are shown in Table 2.

[Comparative Example 1]
In Reference Example 1, the inner wall surface and bottom of the rolling granulator used for supporting the catalytically active component (here, the inner wall surface of the bread is the inner wall portion of the bread when the angle of the central axis of the pan relative to the horizontal plane is 90 °). The bottom of the pan means the bottom of the pan when the angle of the pan central axis with respect to the horizontal plane is 90 °), and the catalytically active component is fixed to a thickness of about 2 mm at maximum, and the metallic luster in the pan Was hardly confirmed, and the inner wall surface was more firmly fixed than the bottom of the pan. The washing process of the rolling granulator in which this fixed substance exists was washed with water by human power. Specifically, water is sprayed over the entire bread to moisten the fixed matter, and then scraped off with a scrubbing brush or the like. Thereafter, water is further sprayed to wash away, and finally the moisture in the pan is wiped off with a cloth or the like. In the water washing process by human power, 2 hours were spent by two people to scrape off the catalyst active component firmly adhered, and about 100 L of waste water was generated. In the rolling granulator after the water washing treatment, the catalyst component was hardly fixed, and the metallic luster of the inner wall surface and the bottom portion of the bread could be confirmed.

  Subsequently, using a rolling granulator after the water washing treatment, a supporting treatment was performed under the same conditions as in Reference Example 1 to obtain a catalyst 2. At this time, the catalytically active component adhering to the inner wall surface and bottom of the bread of the rolling granulator was not peeled off and mixed into the product, and the holding treatment state was not different from that in Reference Example 1.

  The supported rate of catalyst 2 obtained was about 103% by mass, and the yield was about 93% by mass. Table 1 shows the physical properties of Catalyst 2. Further, the obtained catalyst 2 was charged into a reactor in the same manner as in Reference Example 1, and an oxidation reaction was performed under the same conditions. The results are shown in Table 2.

[Example 1]
In Reference Example 1, the rolling granulator used for supporting the catalytically active component was charged with 100 L of a stainless ring (outer diameter 7.0 mm, inner diameter 6.0 mm, grain length 8.0 mm) at a rotation speed of 15 rpm. Rotating for 30 minutes, the rolling granulator was washed.
Compared with the state before the cleaning process after the completion of the cleaning process, the catalytically active components adhered to the inner wall surface and the bottom of the rolling granulator were peeled off, and the metallic luster on the inner wall surface and the bottom of the bread was confirmed. After the cleaning treatment, the stainless steel ring and the peeled catalytically active component were discharged.

  Subsequently, using a rolling granulator after the washing treatment, a supporting treatment was performed under the same conditions as in Reference Example 1 to obtain a catalyst 3. At this time, the catalytically active component adhering to the inner wall surface and bottom of the rolling granulator was not peeled off and mixed into the product, and the supporting treatment state was the same as in Reference Example 1. Moreover, since the cleaning time could be shortened by 75% compared to Comparative Example 1 which was cleaned by conventional water washing, the operating time of the rolling granulator could be extended and the production amount increased by about 20%. The supported rate of catalyst 3 obtained was about 113% by mass, and the yield was 92% by mass. The physical properties of the catalyst 3 are shown in Table 1. Further, the obtained catalyst 3 was charged into a reactor in the same manner as in Reference Example 1, and an oxidation reaction was performed under the same conditions. The results are shown in Table 2.

[Example 2]
A catalyst 4 was obtained in the same manner as in Example 1, except that 100 L of a ceramic support having 8.0 mmφ was charged as the washing treatment condition of the rolling granulator and the rotation time was changed to 60 minutes. Moreover, since the cleaning time could be shortened by 50% with respect to Comparative Example 1 which was cleaned by conventional water washing, the operating time of the rolling granulator could be extended, and the production amount increased by about 14%. The supported rate of catalyst 4 obtained was about 106% by mass, and the yield was about 93% by mass. The physical properties of the catalyst 4 are shown in Table 1. Further, the obtained catalyst 4 was charged into a reactor in the same manner as in Reference Example 1, and an oxidation reaction was performed under the same conditions. The results are shown in Table 2.

[Comparative Example 2]
In Comparative Example 1, a catalyst 5 was obtained in the same manner except that the washing treatment by water washing of the tumbling granulator was performed by two people for 30 minutes. In the washing for 30 minutes, the catalytically active component adhering to the tumbling granulator could not be sufficiently removed, and about 70 L of waste water was generated. After that, when the supporting treatment was started, the catalytically active component adhering to the inner wall surface and the bottom of the rolling granulator was peeled off immediately after the starting of the supporting treatment by the silica-alumina spherical carrier charged in advance, and it was peeled off instead of the carrier. There was a lot of no nuclei (no carrier) in which the loading of the catalytically active component was carried out only with the catalytically active component as a nucleus, and the yield was remarkably reduced. Moreover, in the obtained catalyst, the catalyst active component which peeled off adhered and the catalyst surface was uneven. For this reason, empty walls are generated during filling, the bulk specific gravity is reduced, and the mechanical strength is also low. Although the cleaning time was shortened, the operating time of the rolling granulator could be extended, but the yield was low and the production efficiency was not improved for the increased operating time. The catalyst 5 thus obtained had a loading rate of about 101% by mass and a yield of about 82% by mass. The physical properties of the catalyst 5 are shown in Table 1. Further, the obtained catalyst 5 was charged into a reactor in the same manner as in Reference Example 1, and an oxidation reaction was performed under the same conditions. The results are shown in Table 2. Since many nuclei were absent, the reaction proceeded sequentially, resulting in a low selectivity for acrolein and acrylic acid.

Table 1

Table 2

Claims (5)

A method for cleaning a supporting treatment apparatus for supporting a catalytically active component represented by the following general formula (1) on a carrier, characterized in that the surface of the supporting treatment apparatus is cleaned with an inorganic substance made of metal and / or ceramics. Cleaning method for processing equipment.
_{Mo 12 Bi a Fe b A c} B d C e D f O x (1)
(Where Mo is molybdenum, Bi is bismuth, Fe is iron, A is at least one element selected from the group consisting of cobalt and nickel, and B is selected from the group consisting of alkali metals, alkaline earth metals and thallium. At least one element, C is at least one element selected from the group consisting of tungsten, silicon, aluminum, zirconium and titanium, D is phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic, boron And at least one element selected from the group consisting of zinc, O is oxygen, and a, b, c, d, e, f, and x are atoms of Bi, Fe, A, B, C, D, and O, respectively. 0 <a ≦ 10, 0 <b ≦ 20, 2 ≦ c ≦ 20, 0 ≦ d ≦ 10, 0 ≦ e ≦ 30, 0 ≦ f ≦ 4, and x is each Is a value determined by oxidation states of the element.)   In the inorganic material, the shape is at least one shape selected from the group consisting of a ring shape, a pellet shape, and an indeterminate shape, and the longest distance d between any two ends is 1 mm ≦ d ≦ 30 mm. Item 2. The cleaning method according to Item 1. The cleanup method of claim 1 or 2, wherein the bearing apparatus is a tumbling granulator. Production of a catalyst for producing an unsaturated aldehyde and / or unsaturated carboxylic acid, which comprises carrying a catalytically active component having a step of washing a loaded treatment device by the washing method according to any one of claims 1 to 3 on a carrier. Method. Using at least one compound selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether as a raw material, the corresponding unsaturated aldehyde and / or unsaturated carboxylic acid is obtained by catalytic gas phase oxidation in the presence of molecular oxygen. A method for producing an acid, comprising obtaining a catalyst by the method for producing a catalyst according to claim 4, and using the obtained catalyst in a fixed bed reactor and using the unsaturated aldehyde and / or A method for producing an unsaturated carboxylic acid.