JP5527994B2 - Method for producing oxide catalyst - Google Patents

Description

  The present invention relates to a method for producing an oxide catalyst including a step of firing at a temperature equal to or higher than a melting point of a metal oxide of a catalyst constituent element including Mo and Sb.

  Conventionally, a method for producing (meth) acrylonitrile by an ammoxidation reaction of propylene or isobutylene and a method for producing (meth) acrylic acid by an oxidation reaction of propylene or isobutylene are known. Recently, instead of such a method using propylene or isobutylene, a method of producing (meth) acrylonitrile by a gas-phase catalytic ammoxidation reaction of propane or isobutane, or a (meth) acrylic by a gas-phase catalytic oxidation reaction of propane or isobutane. Attention has been focused on methods for producing acids.

  Until now, various oxide catalysts containing molybdenum (Mo), vanadium (V), niobium (Nb), tellurium (Te) and / or antimony (Sb) have been proposed as catalysts used in the above reaction. For example, Patent Document 1 discloses an oxide catalyst containing Mo—V—Nb—Te, and Patent Document 2 discloses an oxide catalyst containing Mo—V—Nb—Sb. As for these catalysts, it is known that the calcination method during the production process affects the catalyst performance, and the above-mentioned patent document describes the calcination method in detail. In Patent Document 3, gas is introduced into the catalyst bed in order to prevent deterioration of workability due to solidification of the catalyst and adhesion of particles in the firing step for regenerating the metal oxide catalyst containing iron, antimony and phosphorus. It is described that fluid firing is preferable. Patent Document 4 describes that an impact is applied with a knocker, a hammer, or the like in order to prevent adhesion of the oxide catalyst containing Sb to the inner wall of the firing tube in the firing step.

JP 2002-320853 A JP 2003-170044 A JP 7-328447 A JP 2007-216212 A

However, when the present inventors actually calcinate an oxide catalyst containing molybdenum and antimony by fluidized calcination in which a gas is introduced into the catalyst bed, there is a problem that the catalyst cannot be consolidated and particles cannot be adhered to each other. occured.
In particular, when the present inventor performed continuous firing using a rotary kiln, there was a problem that the yield of the catalyst was reduced due to the large amount of oxide catalyst and catalyst precursor adhering as fixed substances. Moreover, the adhering substance adhering in large quantities deteriorated the heat transfer to the powder in the firing tube, and the firing temperature decreased with the passage of time. Furthermore, the thickened material layer substantially shortened the residence time of the flowing powder in the furnace, and it could not be fired under appropriate conditions, and the performance of the resulting catalyst deteriorated. Furthermore, as described in Patent Document 4, it was also considered to give an impact with a knocker, a hammer, or the like, but a sufficient adhesion preventing effect could not always be obtained.

  In view of the above circumstances, the problem to be solved by the present invention is to reduce (suppress) sticking in a firing tube while maintaining the particle shape of an oxide catalyst that generates a compound having a melting point lower than the firing temperature during the firing step. ) To provide a method for efficiently and efficiently producing a catalyst having excellent performance (high yield of the target product).

  As a result of diligent research on the above problems, the present inventors have melted the oxide catalyst and the catalyst precursor when the catalyst contains a constituent element whose melting point of the metal oxide is lower than the firing temperature. It became clear that it adhered to the inner wall of the firing tube. And when manufacturing such a catalyst, when an impact is applied to the calcination tube according to a specific relational expression in the calcination step, sticking in the calcination tube is remarkably reduced, and as a result, excellent The present invention was completed by finding that a catalyst having performance can be efficiently produced in a large amount.

That is, the present invention is as follows.
[1]
A method for producing an oxide catalyst used in a reaction for synthesizing an unsaturated acid or an unsaturated nitrile by gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction of propane or isobutane,
Mo, supplied to the calcining tube a catalyst precursor containing Sb, and firing at a temperature above the melting point of Sb ₂ O _5,
Comprises a step of applying an impact to the calcining tube in the firing step,
In the step of applying the impact, the following formula f = (vibration acceleration) / (A + B)
(In the formula, vibration acceleration: vibration acceleration (m / s ² ) of impact applied to the calcined tube, A: mass% of Mo in the oxide catalyst, B: mass% of Sb in the oxide catalyst)
A method for producing an oxide catalyst, wherein f is represented by 0.08 ≦ f ≦ 50.
[2]
The method for producing an oxide catalyst according to [1], wherein f satisfies 0.1 ≦ f ≦ 40.
[3]
The method for producing an oxide catalyst according to the above [1] or [2], wherein f satisfies 0.2 ≦ f ≦ 30.
[4]
The said calcination process is a manufacturing method of the oxide catalyst in any one of said [1]-[3] including the pre-stage calcination and the main calcination performed after the said pre-stage calcination.
[5]
The method for producing an oxide catalyst according to [4], wherein the main calcination is performed in a temperature range of 550 to 800 ° C.
[6]
The method for producing an oxide catalyst according to [4] or [5] above, wherein the pre-stage calcination is performed in a temperature range of 250 to 400 ° C., and the main calcination is performed in a temperature range of 580 to 750 ° C.
[7]
The method for producing an oxide catalyst according to any one of the above [4] to [6], wherein an impact is applied to the firing tube in the main firing.
[8]
The method for producing an oxide catalyst according to any one of the above [1] to [7], wherein an impact is applied to the calcining tube at a frequency of 1 second to 1 hour.
[9]
The method for producing an oxide catalyst according to any one of the above [1] to [8], wherein an impact is applied to the calcining tube at a frequency of once every 1 second to 30 minutes.
[10]
The method for producing an oxide catalyst according to any one of [1] to [9], wherein the firing tube is fired while rotating.
[11]
The method for producing an oxide catalyst according to any one of the above [1] to [10], wherein a catalyst precursor is continuously supplied to the calcining tube and calcined by continuous calcining.
[12]
When the oxide catalyst contains Mo, V, and Nb, and the atomic ratios of V and Nb per Mo atom are a and b, respectively, 0.1 ≦ a ≦ 1, 0.01 ≦ b ≦ 1 The manufacturing method of the oxide catalyst according to any one of [1] to [11], which is satisfied.
[13]
[1] to [12], wherein the oxide catalyst is supported on silica, and the mass of the silica is 10 to 80% by mass in terms of SiO ₂ with respect to the total mass of the oxide catalyst and the silica. The manufacturing method of the oxide catalyst in any one of these.
[14]
The unsaturated acid comprising the step of contacting propane or isobutane with the oxide catalyst obtained by the production method according to any one of [1] to [13] above and subjecting the oxide catalyst to a gas phase catalytic oxidation or a gas phase catalytic ammoxidation reaction Or the manufacturing method of unsaturated nitrile.

According to the production method of the present invention, the sticking generated in the calcining tube in the step of calcining the catalyst precursor can be remarkably reduced, and as a result, a catalyst having excellent performance can be produced in a large amount and efficiently. It becomes possible to do.
In addition, since the oxide catalyst obtained by the production method of the present invention has excellent catalytic performance, it can be used for gas phase catalytic oxidation or gas phase catalytic ammoxidation of propane or isobutane. Saturated carboxylic acid or unsaturated nitrile (for example, (meth) acrylic acid, (meth) acrylonitrile) can be stably produced in a high yield.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Production method of oxide catalyst]
The method for producing an oxide catalyst according to the present embodiment includes a step of supplying a catalyst precursor containing Mo and Sb to a firing tube and firing at a temperature equal to or higher than the melting point of the metal oxide of the catalyst constituent element. In the step of applying an impact to the fired tube, the following formula f = (vibration acceleration) / (A + B)
(In the formula, vibration acceleration: vibration acceleration (m / s ² ) of impact applied to the calcined tube, A: mass% of Mo in the oxide catalyst, B: mass% of Sb in the oxide catalyst)
F satisfy | fills 0.08 <= f <= 50.

In the present embodiment, the “oxide catalyst” refers to a catalyst containing an oxide of one or more metal components. As will be described later, in the case of a catalyst in which a component functioning as a main catalyst is supported on a carrier, the “oxide catalyst” is a concept including the main catalyst and the carrier. The “catalyst precursor” refers to a compound produced in the production process of an oxide catalyst. In this embodiment, the “melting point of the metal oxide of the catalyst constituent element” means that the metal component contained in the oxide catalyst and / or catalyst precursor is a single oxide (a single metal component and only two components of oxygen). The melting point when the oxide is formed. When one or more kinds of metal components form a single oxide having a plurality of composition formulas, the melting point of the oxide having the lowest melting point among them is meant. For example, according to Phase Diagrams for Ceramists (American Ceramic Society), melting point of molybdenum oxide: MoO ₂ (818 ° C.), MoO ₃ (782 ± 5 ° C.), melting point of antimony oxide: Sb ₂ O ₃ (655 ° C.), Sb _{Since it is 2} O ₅ (525 ° C.), the melting point of the metal oxide of the catalyst constituent element is (782-5) ° C. when molybdenum is included, 525 ° C. when antimony is included, and 525 when both are included. ℃. Specifically, when the oxide catalyst is made of Mo, Sb, V, and Nb and the firing temperature is 650 ° C., the melting point of the antimony single oxide (antimony pentoxide) is lower than the firing temperature. Of “fired at a temperature equal to or higher than the melting point of the metal oxide of the catalyst constituent element”. According to this document, the melting point of niobium oxide Nb ₂ O ₅ is (1510 ° C.), and the melting point of vanadium oxide V ₂ O ₅ is (685 ° C.).

  In the case of an oxide catalyst containing Mo and Sb, Mo and Sb contained in the catalyst and / or catalyst precursor melt, and the oxide catalyst and catalyst precursor are fixed or fused to the inner wall of the calcining tube to form a lump. Easy to do. The present inventors considered that the mass ratio of Mo and Sb contained in the oxide catalyst affects the ease of fixing or fusing of the oxide catalyst and / or catalyst precursor during firing. That is, an oxide catalyst and / or catalyst precursor that generally contains a low melting point Mo and Sb compound is difficult to be fixed or fused to the inner wall of the fired tube, and if the ratio is high, it is easy to be fixed or fused. Conceivable. Therefore, the index f for determining the vibration acceleration of the impact applied during firing is determined according to the mass ratio of Mo and Sb contained in the catalyst.

  In the present embodiment, “calcination temperature” refers to the temperature at which the oxide catalyst and / or catalyst precursor in the calcining tube reaches the highest temperature. In the case of batch calcination, the calcination temperature can be measured by a thermocouple inserted in the oxide catalyst and / or catalyst precursor. In the case of continuous calcination, the oxide catalyst and / or catalyst precursor flow while being deposited in the calcination tube, and the calcination temperature is determined by the thermocouple inserted into the deposited oxide catalyst and / or catalyst precursor. Can be measured.

  The oxide catalyst and / or catalyst precursor of the present embodiment includes a metal component that forms a compound having a melting point lower than the firing temperature. When a compound having a melting point lower than the calcination temperature is generated in the calcination step, this melts during calcination, and an oxide catalyst, a catalyst precursor, etc. are fixed or fused to the inner wall of the calcination tube to form a lump. Particularly in continuous firing, this causes deterioration of heat transfer, a decrease in residence time, and unstable powder flow, making it difficult to stably fire at a desired temperature.

  In the present embodiment, by applying an impact to the firing tube in accordance with the above relational expression in the firing step, it is possible to suppress the above-described fixation to the inner wall of the firing tube and formation of a lump. From this point of view, not only in the case of “calcining at a temperature higher than the melting point of the metal oxide of the catalyst constituent element”, but also in the case where the compound produced during the baking process has a melting point lower than the baking temperature, It should be effective to prevent sticking. However, since it is not realistic to grasp all the compounds generated during calcination, in the present embodiment, in view of the inventor's rule of thumb, whether the melting point of the metal oxide of the catalyst constituent element is lower than the calcination temperature. It is used as an index of occurrence of sticking or the like depending on whether or not.

  In particular, when an impact is applied indirectly through the outer wall of the firing tube, the shape of the catalyst is better than when it is in direct contact with the catalyst by mechanically scraping or crushing the fixed material on the inner wall of the firing tube. It has the advantage that it can be maintained.

  The impact applied to the firing tube is the depth (powder depth) in which the catalyst precursor supplied in the firing tube has accumulated in the firing tube, the diameter, length, thickness and material of the firing tube, and the material and type of the device that applies the impact. -It also depends on the shape and position, the frequency of impact, and the like, so it is preferable to set them appropriately.

In the manufacturing method of the present embodiment, from the viewpoint of sufficiently reducing the fixation to the inner wall of the firing tube, from the viewpoint of preventing breakage of the firing tube and not disturbing the flow of the powder flowing through the firing tube. In the step of applying an impact, the following formula f = (vibration acceleration) / (A + B)
(In the formula, vibration acceleration: vibration acceleration (m / s ² ) of impact applied to the calcined tube, A: mass% of Mo in the oxide catalyst, B: mass% of Sb in the oxide catalyst)
F satisfies 0.08 ≦ f ≦ 50, preferably 0.1 ≦ f ≦ 40, more preferably 0.2 ≦ f ≦ 30. When f is less than 0.08, the impact is insufficient and the catalyst and / or catalyst precursor adheres to the wall surface of the calcining tube, the adhering powder is excessively calcined, and the powder passing inside without adhering is Passes through the firing tube with insufficient heat transfer. As a result, none of the powders can be fired at a desired firing temperature, making it difficult to obtain desired performance. On the other hand, when f exceeds 50, in addition to the firing tube being easily damaged or deformed, the particles flowing in the firing tube are broken by impact, and the particle shape cannot be maintained in a good state in the fluidized bed reaction. It will be scattered in the opposite direction and it will be easy to disturb the flow. Therefore, there is a possibility that the performance may be deteriorated because the firing cannot be performed in a desired firing time.

  In the present embodiment, the “vibration acceleration” of the impact applied to the firing tube is L / 4, 3L / 8, L from the firing tube powder inlet in parallel to the powder flow direction with respect to the firing tube total length L. It means the average value of the values measured at a distance of / 2. The measurement position is the same position as the impact point in the firing tube cross-sectional direction. The vibration acceleration can be measured with a vibrometer attached to the firing tube. As a vibrometer, Asahi Kasei Techno System Co., Ltd. MD220, MD320, or MD550 can be used.

A and B respectively represent A: mass% of Mo in the oxide catalyst, and B: mass% of Sb in the oxide catalyst.
Here, A: the mass% of Mo in the oxide catalyst means the mass ratio of the oxide catalyst when assuming that each constituent element of the oxide catalyst has the highest oxidation number (the highest oxidation number of each constituent component). The mass ratio of the Mo metal atom to the mass ratio of the oxide of the metal oxide, that is, A = {(the mass of Mo atom / the mass ratio of the oxide catalyst) × 100 mass%}. When the oxide catalyst is supported on a carrier, the carrier ratio (% by mass) is excluded from the whole (100% by mass). That is, A = {(Mo atom mass / mass ratio of oxide catalyst) × (100-carrier ratio) mass%}.
For example, in the case of an oxide catalyst represented by Mo ₁ V _0.23 Nb _0.086 Sb _0.27 On / 43 wt% SiO ₂ , it is assumed that each component forms MoO ₃ , VO _2.5 , NbO _2.5 , and SbO _2.5 , respectively. A is obtained as follows.

A = (Mo atomic weight × 1) / (MoO ₃ molecular weight × 1 + VO _2.5 molecular weight × 0.23 + NbO _2.5 molecular weight × 0.086 + SbO _2.5 molecular weight × 0.27) × (100-43) mass%


In the oxide catalyst, since it is not possible to confirm how many oxygen each component is bound to, it is assumed that MoO ₃ , VO _2.5 , NbO _2.5 and SbO _2.5 are formed in this way. The mass ratio of Mo in the oxide catalyst is defined.
Further, B:% by mass of Sb in the oxide catalyst means the mass ratio of Sb metal atoms to the mass ratio of the oxide catalyst when it is assumed that each constituent element of the oxide catalyst has the highest oxidation number. To do. Therefore, in the above example, B is obtained as follows.

B = (Sb atomic weight × 0.27) / (MoO ₃ molecular weight × 1 + VO _2.5 molecular weight × 0.23 + NbO _2.5 molecular weight × 0.086 + SbO _2.5 molecular weight × 0.27) × (100−43) mass%

  The method for applying the impact is not particularly limited, and an air knocker, hammer, hammering device, or the like can be preferably used. The material of the portion directly in contact with the firing tube at the tip of the impact is not particularly limited as long as it is a material having sufficient heat resistance, for example, a general resin that can withstand impact, metal, etc. can be used, Of these, metals are preferred. The metal preferably has a hardness that does not damage or deform the fired tube, and copper or SUS metal can be suitably used. The location to which the impact is applied is not particularly limited and can be performed at a location convenient for operation. However, since the impact can be directly applied to the firing tube without waste, it is applied to the location where the firing tube is not covered with the heating furnace. It is preferable.

  The place where the impact is applied may be one place or a plurality of places. In order to transmit vibration efficiently, it is preferable to apply the impact from a direction perpendicular to the rotation axis. The frequency at which the impact is applied is not particularly limited, but it is preferable that the impact is constantly applied to the calcining tube because adhesion in the calcining tube tends to be reduced more favorably. Here, “constantly applying an impact” refers to applying an impact at a certain frequency or more. Preferably it is 1 second to 1 hour, more preferably 1 second to 30 minutes, more preferably 1 second to 5 minutes, particularly preferably 1 second to 1 minute. Apply shock. The impacts need not always be applied at the same interval, and may be random. For example, after an impact once in 10 seconds, two or more impacts may be applied in 10 seconds, and the frequency may be returned to once in 10 seconds. The frequency at which the impact is applied is appropriately adjusted according to the vibration acceleration, the powder depth of the catalyst precursor supplied into the firing tube, the diameter / length / thickness / material of the firing tube, and the material / type / shape of the device to which the impact is applied. It is preferable.

  The shape of the firing tube used in the manufacturing method of the present embodiment is not particularly limited, but is preferably cylindrical. The heating method is preferably an external heating type, and an electric furnace can be suitably used. The size, material, and the like of the firing tube can be selected appropriately depending on the firing conditions and production amount, but the inner diameter is preferably 70 to 2000 mm, more preferably 100 to 1200 mm, and the length is preferably The thing of 200-10000 mm, More preferably, the thing of 800-8000 mm is used.

  The thickness of the fired tube is not particularly limited as long as it is a sufficient thickness so as not to be damaged by impact, but is preferably 2 mm or more, and more preferably 4 mm or more. Further, from the viewpoint of sufficiently transmitting the impact to the inside of the firing tube, it is preferably 100 mm or less, more preferably 50 mm or less. The material is not particularly limited as long as it has heat resistance and has a strength that is not damaged by an impact. For example, SUS can be suitably used.

  The firing in the manufacturing method of the present embodiment may be either continuous firing or batch firing. Normally, continuous calcination makes it possible to produce a large amount of catalyst compared to batch calcination, but continuous calcination tends to cause variations in residence time and calcination temperature. There is a tendency that firing is difficult at an optimum firing time and firing temperature. Therefore, even if the catalyst composition and firing temperature are the same, in the case of continuous firing, it may be difficult to obtain a yield equivalent to that of batch firing.

  When the firing is performed continuously, a weir plate having a hole for passing the catalyst precursor and / or oxide catalyst in the center is provided in the firing tube perpendicularly to the flow of the catalyst precursor, and the firing tube is provided. It can also be divided into two or more areas. By installing the weir plate, it becomes easy to secure the residence time in the firing tube. The number of weir plates may be one or more. The material of the weir plate is preferably metal, and the same material as that of the firing tube can be suitably used. The height of the weir plate can be adjusted according to the residence time to be secured. For example, when supplying a catalyst precursor at 250 g / hr in a rotary furnace having a SUS-fired tube having an inner diameter of 150 mm and a length of 1150 mm, the barrier plate is preferably 5 to 50 mm, more preferably 10 to 40 mm, and still more preferably 13-35 mm. The thickness of the weir plate is not particularly limited, and is preferably adjusted according to the size of the firing tube. For example, in the case of a rotary furnace having a SUS firing tube having an inner diameter of 150 mm and a length of 1150 mm, it is preferably 0.3 mm or more and 30 mm or less, more preferably 0.5 mm or more and 15 mm or less.

  In the calcination step, it is preferable to rotate the calcination tube in order to prevent cracking, cracks, etc. of the catalyst precursor and to calcinate uniformly. The rotation speed of the firing tube is preferably 0.1 to 30 rpm, more preferably 0.3 to 20 rpm, and still more preferably 0.5 to 10 rpm.

  In the calcination of the dry catalyst precursor, it is preferable to start the temperature increase from a temperature lower than 400 ° C. and continuously or intermittently increase the temperature to a temperature within the range of 550 to 800 ° C.

  The firing atmosphere can be carried out in an air atmosphere or air circulation, but it is preferable to carry out at least a part of the firing while circulating an inert gas substantially free of oxygen such as nitrogen.

  When the calcination is carried out batchwise, the supply amount of the inert gas is 50 N liter / hr or more, preferably 50 to 5000 N liter / hr, more preferably 50 to 4000 N liter / hr per kg of the catalyst precursor (N The liter means a liter measured at standard temperature and pressure conditions, that is, 0 ° C. and 1 atm). When the calcination is performed continuously, the supply amount of the inert gas is 50 N liters or more, preferably 50 to 5000 N liters, preferably 50 to 4000 N liters per 1 kg of the catalyst precursor (N liter is a standard temperature / pressure). Condition, ie, liters measured at 0 ° C. and 1 atm). At this time, the inert gas and the catalyst precursor may be counter-current or co-current, but counter-current contact is preferable in consideration of gas components generated from the catalyst precursor and air mixed in a small amount together with the catalyst precursor.

  The calcination step can be carried out even in one stage, but it is preferable to perform the pre-stage calcination before the main calcination because the reduction rate of the catalyst tends to be easily adjusted to an appropriate range efficiently. As a temperature range, it is preferable to perform pre-baking at 250 to 400 ° C. and main baking at 550 to 800 ° C. The pre-baking and the main baking may be performed continuously, or the main baking may be performed again after the pre-baking is once completed. Moreover, each of pre-stage baking and main baking may be divided into several stages. When firing is performed separately in the pre-stage firing and the main firing, it is preferable to apply an impact in the main firing.

  The pre-stage calcination is preferably carried out in the range of a heating temperature of 250 ° C. to 400 ° C., preferably 300 ° C. to 400 ° C. under an inert gas flow. Although it is preferable to hold at a constant temperature within a temperature range of 250 ° C. to 400 ° C., the temperature may fluctuate within the range of 250 ° C. to 400 ° C., or the temperature may be gradually increased or decreased. The holding time of the heating temperature is 30 minutes or more, preferably 3 to 12 hours. The temperature rising pattern until reaching the pre-stage firing temperature may be increased linearly, or the temperature may be increased by drawing an upward or downward convex arc.

  The average rate of temperature rise during the temperature rise until reaching the pre-stage firing temperature is not particularly limited, but is preferably 0.1 to 15 ° C / min, more preferably 0.5 to 5 ° C / min, and still more preferably 1 ˜2 ° C./min.

  The main calcination is preferably performed at a heating temperature of 550 to 800 ° C., preferably 580 to 750 ° C., more preferably 600 to 720 ° C., and particularly preferably 620 to 700 ° C. under an inert gas flow. Although it is preferable to hold at a constant temperature within a temperature range of 620 to 700 ° C, the temperature may fluctuate within the range of 620 to 700 ° C, or the temperature may be gradually increased or decreased. The firing time is 0.5 to 20 hours, preferably 1 to 15 hours. If desired, an oxidizing component (for example, oxygen) or a reducing component (for example, ammonia) may be added to the firing atmosphere under an inert gas flow. The temperature rising pattern until reaching the main firing temperature may be increased linearly, or the temperature may be increased by drawing an upward or downward convex arc.

  The average rate of temperature increase during the temperature increase until reaching the main firing temperature is not particularly limited, but is preferably 0.1 to 15 ° C / min, more preferably 0.5 to 10 ° C / min, and still more preferably 1 ˜5 ° C./min.

  The average temperature decrease rate after the completion of the main firing is 0.01 to 1000 ° C./min, preferably 0.05 to 100 ° C./min, more preferably 0.1 to 50 ° C./min, and further preferably 0.5 to 10 ° C. / Min. Moreover, it is also preferable to hold once at a temperature lower than the main firing temperature. The temperature to be held is 5 ° C., preferably 10 ° C., more preferably 50 ° C. lower than the main firing temperature. The holding time is 0.5 hours or more, preferably 1 hour or more, more preferably 3 hours or more, and particularly preferably 10 hours or more.

  When the calcining tube is divided by a dam plate, the catalyst precursor passes continuously through at least two, preferably 2 to 20, more preferably 4 to 15 regions, each of which can be temperature controlled. For example, in the case where seven pieces of dam plates are installed so as to divide the length of the portion of the firing tube that enters the heating furnace into eight equal parts and a firing tube partitioned into eight sections is used, in order to obtain the desired firing pattern, Adjustments can be made as follows. In the pre-stage calcination, the temperature of the thermocouple inserted into the central portion of the catalyst precursor staying in the calcination tube is counted from the supply side of the catalyst precursor, respectively, in the range 1: 100 to 300 ° C., and the area 2: 150. ~ 400 ° C, zone 3: 200-400 ° C, zone 4: 200-400 ° C, zone 5: 200-400 ° C, zone 6: 200-400 ° C, zone 7: 200-400 ° C, zone 8: 200-400 It is preferable to adjust so that it may become ° C. Similarly, in this firing, zone 1: 350-700 ° C., zone 2: 400-750 ° C., zone 3: 550-750 ° C., zone 4: 550-750 ° C., zone 5: 400-700 ° C., zone 6: 400 It is preferable to adjust so that it may become -700 degreeC, area 7: 400-700 degreeC, and area 8: 350-700 degreeC.

[Oxide catalyst]
Examples of the oxide catalyst obtained by the production method of the present embodiment include compounds represented by the following general formula (1), including molybdenum, vanadium, niobium, and antimony.
_{Mo 1 V a Nb b Sb c} Y d O n (1)
(Wherein Y represents at least one element selected from Mn, W, B, Ti, Al, Te, alkali metal, alkaline earth metal and rare earth metal, and a, b, c, d and n Indicates the atomic ratio of V, Nb, Sb, Y per molybdenum (Mo) atom, respectively, 0.1 ≦ a ≦ 1, 0.01 ≦ b ≦ 1, 0.01 ≦ c ≦ 1, 0 ≦ d ≦ 1, and n represents the number of oxygen atoms determined by the valence of a constituent element other than oxygen.)

  The atomic ratios a, b, c, and d per Mo atom are 0.1 ≦ a ≦ 1, 0.01 ≦ b ≦ 1, 0.01 ≦ c ≦ 1, and 0 ≦ d ≦ 1, respectively. Preferably, 0.1 ≦ a ≦ 0.5, 0.01 ≦ b ≦ 0.5, 0.1 ≦ c ≦ 0.5, 0.0001 ≦ d ≦ 0.5 are more preferable. More preferably, 2 ≦ a ≦ 0.3, 0.05 ≦ b ≦ 0.2, 0.2 ≦ c ≦ 0.3, and 0.0002 ≦ d ≦ 0.4.

  A material containing Mo and Sb is easily oxidized in the fired tube, and is an oxide catalyst suitable for applying the manufacturing method of the present embodiment.

When the catalyst is used in a fluidized bed, sufficient strength is required, so that the oxide catalyst is preferably supported on silica. The oxide catalyst is preferably 10 to 80% by mass, more preferably 20 to 60% by mass, in terms of SiO ₂ , based on the total mass of the oxide catalyst (the oxide of the catalyst constituent element serving as the main catalyst) and silica. More preferably, it is supported on 30 to 55% by mass of silica. The amount of silica as a support is 10% by mass or more based on the total mass of the oxide catalyst and silica from the viewpoint of strength and prevention of powdering, ease of stable operation when using the catalyst, and reduction of replenishment of the lost catalyst. From the viewpoint of achieving sufficient catalytic activity, it is preferably 80% by mass or less based on the total mass of the oxide catalyst and silica. In particular, when the catalyst is used in a fluidized bed, if the amount of silica is 80% by mass or less, the specific gravity of the silica-supported catalyst (oxide catalyst + silica support) is appropriate, and it is easy to produce a good fluidized state.

  In the method for producing an oxide catalyst of the present embodiment, the “catalyst precursor” supplied to the calcining tube can be obtained, for example, by performing the following raw material preparation step and drying step. Hereinafter, each step will be described.

(Raw material preparation process)
This step is a step of obtaining a raw material preparation liquid by dissolving and mixing a raw material containing a metal component in a solvent such as water.

It does not specifically limit as a raw material containing a metal component, For example, the following compound can be used. Examples of the Mo material include molybdenum oxide, ammonium dimolybdate, ammonium heptamolybdate, phosphomolybdic acid, and silicomolybdic acid. Among these, ammonium heptamolybdate can be preferably used. Examples of the raw material for V include vanadium pentoxide, ammonium metavanadate, and vanadyl sulfate. Among them, ammonium metavanadate can be preferably used. Examples of the raw material for Nb include at least one selected from the group consisting of niobic acid, an inorganic acid salt of niobium, and an organic acid salt of niobium. Among these, niobic acid is preferable. Niobic acid is represented by Nb ₂ O ₅ .nH ₂ O and is also referred to as niobium hydroxide or niobium oxide hydrate. Among them, it is preferable to use a niobium raw material liquid in which the niobium raw material contains a dicarboxylic acid and a niobium compound, and the dicarboxylic acid / niobium molar ratio is 1 to 4. As the raw material of Sb, antimony oxide can be preferably used.

Below, this process is demonstrated concretely by the example which prepares the raw material preparation liquid containing Mo, V, Nb, and Sb.
First, ammonium heptamolybdate, ammonium metavanadate, and antimony trioxide powder are added to water and heated to 80 ° C. or higher to prepare a mixed solution (A). At this time, for example, when the catalyst contains Te, B, or Ce, telluric acid, boric acid, and cerium nitrate can be added simultaneously.
Next, niobic acid and oxalic acid are heated and stirred in water to prepare a mixed solution (B). The mixed liquid (B) is obtained by the method shown below. That is, niobic acid and oxalic acid are added to water and stirred to obtain an aqueous solution or aqueous suspension. In the case of suspension, dissolution of the niobium compound can be promoted by adding a small amount of aqueous ammonia or heating. The aqueous solution or suspension is then cooled and filtered to obtain a niobium-containing liquid. Cooling can be carried out simply by ice-cooling, and filtration can be carried out simply by decantation or filtration. Oxalic acid can be appropriately added to the obtained niobium-containing liquid to prepare a suitable oxalic acid / niobium ratio. The molar ratio of oxalic acid / niobium is preferably 2-5, more preferably 2-4. Furthermore, hydrogen peroxide may be added to the obtained niobium mixed solution to prepare a mixed solution (B). At this time, the molar ratio of hydrogen peroxide / niobium is preferably 0.5 to 20, and more preferably 1 to 10.
Next, the mixed solution (A) and the mixed solution (B) are mixed according to the target composition to obtain a raw material preparation solution. For example, when the catalyst contains W or Mn, a compound containing W is suitably mixed to obtain a raw material preparation solution. As the compound containing W, for example, ammonium metatungstate is suitably used. As a compound containing Mn, for example, manganese nitrate is preferably used. The compound containing W or Mn can be added to the mixed liquid (A), or can be added simultaneously when the mixed liquid (A) and the mixed liquid (B) are mixed. When the oxide catalyst is supported on a silica carrier, the raw material preparation liquid is prepared so as to contain the silica sol, and in this case, the silica sol can be appropriately added.
Moreover, when using antimony, it is preferable to add hydrogen peroxide to the liquid containing the component of the liquid mixture (A) or the liquid mixture (A) in the middle of preparation. At this time, H ₂ O ₂ / Sb (molar ratio) is preferably 0.01 to 5, more preferably from 0.05 to 4. Moreover, it is preferable at this time to continue stirring at 30 ° C. to 70 ° C. for 30 minutes to 2 hours. The catalyst raw material preparation liquid thus obtained may be a uniform solution, but is usually a slurry.

(Drying process)
This step is a step of drying the raw material preparation liquid obtained in the above-described step to obtain a (dry) catalyst precursor. Drying can be performed by a known method, for example, spray drying or evaporation to dryness, but it is preferable to obtain a microspherical dry catalyst precursor by spray drying. The atomization in the spray drying method can be performed by a centrifugal method, a two-fluid nozzle method, or a high-pressure nozzle method. As the drying heat source, air heated by steam, an electric heater or the like can be used. The dryer inlet temperature of the spray dryer is preferably 150 to 300 ° C, and the dryer outlet temperature is preferably 100 to 160 ° C.

[Production method of unsaturated acid and unsaturated nitrile]
Using the oxide catalyst obtained by the production method of the present embodiment, propane or isobutane is reacted with molecular oxygen in the gas phase (gas phase catalytic oxidation reaction), and the corresponding unsaturated carboxylic acid (acrylic acid or Methacrylic acid) can be produced. Also, using this catalyst, propane or isobutane can be reacted with ammonia and molecular oxygen in the gas phase (gas phase catalytic ammoxidation reaction) to produce the corresponding unsaturated nitrile (acrylonitrile or methacrylonitrile). it can.

  Propane or isobutane and ammonia feeds do not necessarily have to be high purity, and industrial grade gases can be used. As the supply oxygen source, air, pure oxygen, or air enriched with pure oxygen can be used. Furthermore, helium, neon, argon, carbon dioxide gas, water vapor, nitrogen or the like may be supplied as a dilution gas.

  In the case of an ammoxidation reaction, the molar ratio of ammonia supplied to the reaction system to propane or isobutane is 0.3 to 1.5, preferably 0.8 to 1.2. In both the oxidation reaction and the ammoxidation reaction, the molar ratio of molecular oxygen supplied to the reaction system to propane or isobutane is 0.1 to 6, preferably 0.1 to 4.

  For both the oxidation reaction and the ammoxidation reaction, the reaction pressure is 0.5 to 5 atm, preferably 1 to 3 atm, the reaction temperature is 350 ° C. to 500 ° C., preferably 380 ° C. to 470 ° C., and contact The time is 0.1 to 10 (sec · g / cc), preferably 0.5 to 5 (sec · g / cc).

In the present embodiment, the contact time is defined by the following equation.
Contact time (sec · g / cc) = (W / F) × 273 / (273 + T) × P
here,
W = mass of catalyst (g),
F = Raw material mixed gas flow rate (Ncc / sec) in standard state (0 ° C., 1 atm),
T = reaction temperature (° C.)
P = reaction pressure (atm).
Propane conversion and acrylonitrile yield follow the following definitions, respectively.
Propane conversion (%) = (moles of propane reacted) / (moles of propane fed) × 100
Acrylonitrile yield (%) = (Mole number of acrylonitrile produced) / (Mole number of supplied propane) × 100

  Conventional reaction systems such as a fixed bed, fluidized bed, and moving bed can be adopted as the reaction system, but the heat of reaction can be easily removed and the temperature of the catalyst layer can be maintained almost uniformly, and the catalyst is extracted from the reactor during operation. Or a fluidized bed reaction is preferable because a catalyst can be added.

  Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples. However, the present embodiment is not limited to these examples.

(Preparation of niobium raw material liquid)
A niobium raw material solution was prepared by the following method. Niobic acid 76.33 kg containing 80.2% by mass as Nb ₂ O ₅ and oxalic acid dihydrate [H ₂ C ₂ O ₄ .2H ₂ O] 29.02 g were mixed in 500 kg of water. The molar ratio of charged oxalic acid / niobium was 5.0, and the concentration of charged niobium was 0.532 (mol-Nb / kg-solution).
This solution was heated and stirred at 95 ° C. for 1 hour to obtain an aqueous solution in which the niobium compound was dissolved. The aqueous solution was allowed to stand and ice-cooled, and then the solid was separated by suction filtration to obtain a uniform aqueous niobium compound solution. The same operation was repeated several times, and the obtained niobium compound aqueous solution was combined into one niobium raw material solution. The molar ratio of oxalic acid / niobium in this niobium raw material liquid was 2.60 according to the following analysis.
In a crucible, 10 g of this niobium raw material solution was precisely weighed, dried overnight at 95 ° C., and then heat-treated at 600 ° C. for 1 hour to obtain 0.7868 g of Nb ₂ O ₅ . From this result, the niobium concentration was 0.592 (mol-Nb / kg-solution).
3 g of this niobium raw material solution was precisely weighed into a 300 mL glass beaker, 200 mL of hot water at about 80 ° C. was added, and then 10 mL of 1: 1 sulfuric acid was added. The obtained solution was titrated with 1 / 4N KMnO ₄ under stirring while maintaining the liquid temperature at 70 ° C. on a hot stirrer. The end point was a point where a faint pale pink color by KMnO ₄ lasted for about 30 seconds or more. The concentration of oxalic acid was 1.54 (mol-oxalic acid / kg) as a result of calculation according to the following formula from titration.
2KMnO ₄ + 3H ₂ SO ₄ + 5H ₂ C ₂ O ₄ → K ₂ SO ₄ + 2MnSO ₄ + 10CO ₂ + 8H ₂ O
The obtained niobium raw material liquid was used as a niobium raw material liquid in the production of the following oxide catalyst.

Example 1
A silica-supported catalyst having a composition formula of Mo ₁ V _0.23 Nb _0.086 Sb _0.27 O _n / 43 mass% -SiO ₂ was produced as follows.
(Preparation of raw material mixture)
44.11 kg of water, 9.40 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 1.42 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 2.09 kg of O ₃ ] was added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
To 7.68 kg of the niobium raw material liquid, 1.03 kg of hydrogen peroxide containing 30% by mass of H ₂ O ₂ was added. While maintaining the liquid temperature at about 20 ° C., the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After the aqueous mixed liquid A-1 was cooled to 70 ° C., 16.97 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Next, 2.43 kg of hydrogen peroxide containing 30% by mass of H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Furthermore, a liquid in which 3.44 kg of fumed silica was dispersed in 48.2 kg of water was added to obtain a raw material preparation liquid.
In order to perform a “dry catalyst precursor preparation” step and a “calcination” step, which will be described later, in a continuous manner, this step was repeated 70 times to prepare a total of about 1400 kg of a raw material preparation solution.
(Preparation of dry catalyst precursor)
The obtained raw material preparation liquid was supplied to a centrifugal spray dryer and dried to continuously obtain a microspherical dry catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
(Baking)
The dried catalyst precursor thus obtained was divided into eight halves of a heating furnace portion of seven dam plates having a height of 150 mm by a SUS cylindrical firing tube having an inner diameter of 500 mm, a length of 3500 mm, and a wall thickness of 20 mm. Circulate at a rate of 20 kg / hr to the installed one, raise the temperature up to 360 ° C. over about 4 hours while rotating the firing tube at 5 rpm under a nitrogen gas flow of 600 Nl / min, and at 360 ° C. for 3 hours. The heating furnace temperature was adjusted so that the temperature profile was maintained, and the pre-stage baking powder was obtained by pre-stage baking. In another SUS firing tube with an inner diameter of 500 mm, a length of 3500 mm, and a wall thickness of 20 mm, seven dam plates with a height of 150 mm were installed so that the length of the heating furnace portion was equally divided into 8 parts. The pre-stage calcined powder was circulated at a speed of 15 kg / hr. At that time, the powder introduction side portion (the portion not covered by the heating furnace) of the firing tube is a hammering device in which the hammering tip is provided with a SUS hammer with a mass of 14 kg, and the firing tube is perpendicular to the rotation axis. While hitting once every 5 seconds from the height of the upper 250 mm, the temperature was raised to 645 ° C. under a nitrogen gas flow of 500 Nl / min at 2 ° C./min, baked at 645 ° C. for 2 hours, and 1 ° C./min. The temperature of the heating furnace was adjusted so as to obtain a temperature profile for decreasing the temperature, and the oxide catalyst was obtained by performing main firing. During the main calcination, the calcination temperature did not decrease, and an oxide catalyst could be obtained at a stable rate. The vibration acceleration was measured by a vibrometer (MD-220 manufactured by Asahi Kasei Techno System Co., Ltd.) and found to be 48 m / s ² and f = 1.75.
(Evaluation of catalyst performance)
An oxide catalyst obtained 48 hours after the start of calcination was charged into a Vycor glass fluidized bed reaction tube having an inner diameter of 25 mm, and propane: ammonia: oxygen: helium = 1: 0 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of .85: 3.0: 11 was passed at a contact time of 3.0 (sec · g / cc). As a result of evaluating the performance of the catalyst, the propane conversion was 89.5% and the acrylonitrile yield was 53.6%.

(Example 2)
The dried catalyst precursor is a SUS cylindrical firing tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, and six dam plates with a height of 30 mm are installed to divide the length of the heating furnace into seven equal parts. Was baked in the same manner as in Example 1 except that 10 N liter / min of nitrogen gas was circulated at a rate of 340 g / hr to obtain a pre-stage baked powder. The pre-stage calcined powder was added to a SUS fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. A hammering device that circulates at a speed of 200 g / hr, and places the powder introduction side portion of the firing tube (the portion that is not covered by the heating furnace) with a hammer of 2 kg made of SUS at the tip of the striking unit, The main calcination was performed in the same manner as in Example 1 except that nitrogen gas of 6 N liter / min was circulated in a vertical direction while applying a blow once every 15 seconds from the height of 30 mm above the firing tube. A catalyst was obtained. During the main calcination, the calcination temperature did not decrease, and an oxide catalyst could be obtained at a stable rate. When the vibration acceleration was measured in the same manner as in Example 1, it was 63 m / s ² and f = 2.30. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 90.1% and the acrylonitrile yield was 53.7%.

(Example 3)
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. The body was passed at a rate of 340 g / hr and nitrogen gas was passed at a rate of 10 N liters / min. The pre-stage calcined powder was applied to a SUS-fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, with seven dam plates set to 30 mm in height so that the length of the heating furnace was divided into eight equal parts. It distributed at a rate of 200 g / hr. At that time, the main calcination was performed in the same manner as in Example 1 except that 6 N liter / min of nitrogen gas was circulated while striking with an air knocker (Seisin SK-30LPS) having a pneumatic pressure of 0.25 MPa once every 30 seconds. As a result, an oxide catalyst was obtained. During the main calcination, the calcination temperature did not decrease, and an oxide catalyst could be obtained at a stable rate. When the vibration acceleration was measured in the same manner as in Example 1, it was 20 m / s ² and f = 0.73. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 89.1% and the acrylonitrile yield was 53.4%.

Example 4
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. The body was passed at a rate of 340 g / hr and nitrogen gas was passed at a rate of 10 N liters / min. The pre-stage calcined powder was applied to a SUS-fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, with seven dam plates set to 30 mm in height so that the length of the heating furnace was divided into eight equal parts. A hammering device that circulates at a speed of 200 g / hr, and places the powder introduction side portion of the firing tube (the portion not covered by the heating furnace) with a hammer having a mass of 50 g made of SUS on the tip, The main catalyst was calcined in the same manner as in Example 1 except that 6 N liter / min of nitrogen gas was circulated in the vertical direction from the height of 30 mm above the calcining tube at a rate of once every 5 seconds. Got. When the vibration acceleration was measured in the same manner as in Example 1, it was 5 m / s ² and f = 0.18. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 88.4% and the acrylonitrile yield was 52.5%.

(Example 5)
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 90 mm, a length of 900 mm, and a wall thickness of 2 mm. The body was circulated at a rate of 91 g / hr and nitrogen gas was circulated at 2.7 N liters / min. The pre-stage calcined powder was placed on a SUS calcining tube with an inner diameter of 90 mm, a length of 900 mm, and a wall thickness of 2 mm, and seven dam plates with a height of 18 mm installed so that the length of the heating furnace was divided into eight equal parts. It distributes at a speed of 60 g / hr, and a hammering device in which the powder introduction side portion of the firing tube (the portion not covered by the heating furnace) is installed with a hammer with a hammer of 3 kg made of SUS at the tip of the hammer is attached to the rotating shaft. The main catalyst was calcined in the same manner as in Example 1 except that 1.5 N liters / min of nitrogen gas was circulated in the vertical direction from the height of the upper portion of the calcining tube 20 mm while applying a blow once every 10 seconds. Got. When vibration acceleration was measured using MD320 manufactured by Asahi Kasei Techno System Co., Ltd., it was 280 m / s ² and f = 10.21. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 88.1% and the acrylonitrile yield was 53.3%.

(Example 6)
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. The body was passed at a rate of 340 g / hr and nitrogen gas was passed at a rate of 10 N liters / min. The pre-stage calcined powder was applied to a SUS-fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, with seven dam plates set to 30 mm in height so that the length of the heating furnace was divided into eight equal parts. A hammering device that circulates at a speed of 200 g / hr, and places the powder introduction side portion of the firing tube (the portion that is not covered by the heating furnace) with a hammer with a mass of 5 kg made of SUS, on the rotating shaft The main catalyst was calcined in the same manner as in Example 1 except that 6 N liters / min of nitrogen gas was circulated from the height of 100 mm above the calcining tube in the vertical direction with a blow once every 15 seconds. Got. When the vibration acceleration was measured using MD550 manufactured by Asahi Kasei Techno System Co., Ltd., it was 500 m / s ² and f = 18.2. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 87.8% and the acrylonitrile yield was 52.6%.

(Comparative Example 1)
The pre-stage calcined powder was heated up to 480 ° C. at 2 ° C./min, calcined at 480 ° C. for 2 hours, and the furnace temperature was adjusted so that the temperature profile was lowered at 12 ° C./min. Except for this, an oxide catalyst was obtained in the same manner as in Example 2. When the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 49.5% and the acrylonitrile yield was 24.4%.

(Comparative Example 2)
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. The body was passed at a rate of 340 g / hr and nitrogen gas was passed at a rate of 10 N liters / min. The pre-stage calcined powder was applied to a SUS-fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, with seven dam plates set to 30 mm in height so that the length of the heating furnace was divided into eight equal parts. A hammering device that circulates at a speed of 200 g / hr, and that has a powder introduction side portion of the firing tube (a portion not covered by the heating furnace) with a hammer with a 30 g mass made of SUS at the tip of the hammer, The main catalyst was calcined in the same manner as in Example 1 except that 6 N liter / min of nitrogen gas was circulated in the vertical direction from the height of 20 mm from the top of the calcining tube at 30 seconds, and the oxide catalyst. Got. When the vibration acceleration was measured in the same manner as in Example 1, it was 2 m / s ² and f = 0.07. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 86.5% and the acrylonitrile yield was 50.5%.

(Comparative Example 3)
The dried catalyst precursor is a SUS cylindrical fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm. The body was passed at a rate of 340 g / hr and nitrogen gas was passed at a rate of 10 N liters / min. The pre-stage calcined powder was applied to a SUS-fired tube with an inner diameter of 150 mm, a length of 1150 mm, and a wall thickness of 7 mm, with seven dam plates set to 30 mm in height so that the length of the heating furnace was divided into eight equal parts. A hammering device that circulates at a speed of 200 g / hr, and that has a powder introduction side portion of the firing tube (a portion that is not covered by the heating furnace) with a hammer of 8 kg mass made of SUS at the tip of the striking portion is attached to the rotating shaft. The main catalyst was calcined in the same manner as in Example 1 except that 6 N liters / min of nitrogen gas was circulated from the height of 250 mm above the calcining tube in the vertical direction with a blow once every 30 seconds. Got. When the vibration acceleration was measured in the same manner as in Example 6, it was 1500 m / s ² and f = 54.7. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 86.1% and the acrylonitrile yield was 51.0%.

(Example 7)
The main firing was performed in the same manner as in Example 3 except that the frequency of impact was set to once every 30 minutes. When the obtained catalyst was used for an ammoxidation reaction in the same manner as in Example 1, the propane conversion was 87.9% and the acrylonitrile yield was 52.7%.

(Example 8)
Into an SUS cylindrical calcining tube having an inner diameter of 500 mm, a length of 1000 mm, and a wall thickness of 20 mm, 40 kg of the dried catalyst precursor obtained by the same method as in Example 1 was placed, and nitrogen gas was circulated at 100 Nl / min, followed by calcining. While rotating the tube at 7 rpm, the temperature was raised to 350 ° C. over about 4 hours, and pre-baked with a temperature profile maintained at 350 ° C. for 3 hours to obtain a pre-baked powder. 35 kg of the pre-stage calcined powder is put into another SUS calcining tube having an inner diameter of 500 mm, a length of 1000 mm, and a wall thickness of 20 mm, nitrogen gas is circulated at 20 N liters / min, and the calcining tube is rotated at 7 rpm. The temperature was raised at / min, calcined at 645 ° C. for 2 hours, and calcined at a temperature profile of 1 ° C./min. To obtain an oxide catalyst. At this time, the powder introduction side portion of the firing tube (the portion not covered with the heating furnace) is a hammering device in which the hammering tip is provided with a SUS hammer with a mass of 10 kg, and the firing tube is perpendicular to the rotation axis. The main firing was performed while hitting once every 10 seconds from the height of the upper 50 mm. When the vibration acceleration was measured in the same manner as in Example 1, it was 7 m / s ² and f = 0.26. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 90.6% and the acrylonitrile yield was 54.0%.

Example 9
The dry catalyst precursor was prepared by placing seven dam plates 15 mm high in a SUS cylindrical calcining tube with an inner diameter of 80 mm, a length of 1300 mm, and a wall thickness of 2 mm so that the length of the heating furnace portion was divided into eight equal parts. The pre-stage calcined powder was obtained in the same manner as in Example 1 except that the body was circulated at a rate of 86 g / hr and nitrogen gas was circulated at 2.2 N liter / min. The pre-stage calcined powder was placed on a SUS calcining tube with an inner diameter of 80 mm, a length of 1300 mm, and a wall thickness of 2 mm, and seven dam plates with a height of 30 mm, which were installed so that the length of the heating furnace was divided into eight equal parts. It distributes at a speed of 50 g / hr, and the powder introduction side portion of the firing tube (the portion not covered with the heating furnace) is a hammering device in which the hammering tip is provided with a SUS hammer with a mass of 2 kg. The main catalyst was calcined in the same manner as in Example 1 except that 1.7 N liter / min of nitrogen gas was circulated from the height of 15 mm above the calcining tube in the vertical direction, once in 20 seconds. Got. During the main calcination, the calcination temperature did not decrease, and an oxide catalyst could be obtained at a stable rate. When the vibration acceleration was measured in the same manner as in Example 1, it was 120 m / s ² and f = 4.38. Further, when the performance of the catalyst was evaluated in the same manner as in Example 1, the propane conversion was 88.9% and the acrylonitrile yield was 53.1%.

(Example 10)
The dried catalyst precursor is a SUS cylindrical calcining tube with an inner diameter of 300 mm, a length of 800 mm, and a thickness of 7 mm. The pre-stage calcined powder was obtained in the same manner as in Example 1 except that the body was circulated at a rate of 1.2 kg / hr and nitrogen gas was circulated at 35 N liter / min. The pre-stage calcined powder is applied to a SUS fired tube with an inner diameter of 300 mm, a length of 800 mm, and a wall thickness of 7 mm, and seven dam plates set to 70 mm in height so that the length of the heating furnace is divided into eight equal parts. Circulate at a rate of 0.7 kg / hr, rotate the powder introduction side portion of the firing tube (the portion not covered by the heating furnace) with a hammering device in which the tip of the striking part is installed with a SUS hammer with a mass of 8 kg The main catalyst was calcined in the same manner as in Example 1 except that 23 N liters / min of nitrogen gas was circulated from the height of 50 mm above the calcining tube in the direction perpendicular to the axis, while hitting once every 20 seconds. Got. During the main calcination, the calcination temperature did not decrease, and an oxide catalyst could be obtained at a stable rate. When the vibration acceleration was measured in the same manner as in Example 1, it was 38 m / s ² and f = 1.39. Further, when the catalyst performance was evaluated in the same manner as in Example 1, the propane conversion was 88.8% and the acrylonitrile yield was 53.2%.

(Example 11)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} W 0.02 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
21.6 kg of water, 4.60 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.70 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 1.03 kg of O ₃ ] was added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.50 kg of hydrogen peroxide containing 30% by mass of H ₂ O ₂ was added to 3.76 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.19 kg of hydrogen peroxide containing 30% by mass of H ₂ O ₂ was added and stirred and mixed at 50 ° C. for 1 hour, and then aqueous liquid B-1 was added. Subsequently, 0.24 kg of ammonium metatungstate containing 50.2% by mass as WO ₃ was added, and further a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added to prepare a raw material preparation liquid Got.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 55 m / s ² and f = 2.04. In addition, W was used for calculation of the mass% of Mo and Sb, assuming that WO3 is formed.
(Evaluation of catalyst performance)
As in Example 1, performance evaluation in the ammoxidation reaction of the oxide catalyst obtained from the exit of the calcining tube was performed 48 hours after the start of calcination. As a result, the propane conversion was 90.5% and the acrylonitrile yield was 53.8%. Met.

(Example 12)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} W 0.035 Ce 0.008 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
21.1 kg of water, 4.50 kg of ammonium heptamolybdate [(NH ₄ ) 6 Mo ₇ O ₂₄ .4H ₂ O], 0.68 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O ₃ ] is added to 1.00 kg and cerium nitrate [Ce (NO ₃ ) ₃ .6H ₂ O] is added to 0.090 kg and heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.49 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.68 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.16 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Subsequently, 0.41 kg of ammonium metatungstate containing 50.2% by mass as WO ₃ was added, and further a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added to prepare a raw material preparation liquid Got.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.

(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 54 m / s ² and f = 2.04. In addition, W was used for calculation of the mass% of Mo and Sb on the assumption that WO3 and Ce would form CeO2.
(Evaluation of catalyst performance)
When the performance in the ammoxidation reaction of the oxide catalyst obtained from the calcining tube outlet was evaluated 48 hours after the start of calcination by the same method as in Example 1, the propane conversion was 90.8% and the acrylonitrile yield was 53.9. %Met.

(Example 13)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} B 0.1 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
21.7 kg of water, 4.63 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.70 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 1.03 kg of O ₃ ] and 0.16 kg of boric acid [H ₃ BO ₃ ] were added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
To 3.78 kg of the niobium raw material liquid, 0.51 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.19 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added and stirred and mixed at 50 ° C. for 1 hour, and then aqueous liquid B-1 was added. Furthermore, a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 60 m / s ² and f = 2.22. In addition, B was used for calculation of the mass% of Mo and Sb on the assumption that BO1.5 was formed.
(Evaluation of catalyst performance)
As in Example 1, when the performance in the ammoxidation reaction of the oxide catalyst obtained from the outlet of the calcining tube was evaluated 48 hours after the start of calcination, the propane conversion was 90.3% and the acrylonitrile yield was 53.7%. there were.

(Example 14)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} W 0.025 Mn 0.003 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
20.8 kg of water, 4.57 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.69 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 1.03 kg of O ₃ ] was added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.50 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.74 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.18 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added and stirred and mixed at 50 ° C. for 1 hour, and then aqueous liquid B-1 was added. Subsequently, 0.022 kg of manganese nitrate [Mn (NO ₃ ) ₂ .6H ₂ O], 0.30 kg of ammonium metatungstate containing 50% as WO ₃ were added, and 1.72 kg of fumed silica was further added by 24. A liquid dispersed in 1 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 55 m / s ² and f = 2.05. In addition, W was used for calculation of the mass% of Mo and Sb, assuming that WO3 and Mn form MnO3.5.
(Evaluation of catalyst performance)
When the performance in the ammoxidation reaction of the oxide catalyst obtained from the calcining tube outlet was evaluated 48 hours after the start of calcination by the same method as in Example 1, the propane conversion was 90.1% and the acrylonitrile yield was 53.6. %Met.

(Example 15)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} Bi 0.02 Ce 0.006 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
21.5 kg of water, 4.58 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.69 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O _3] was 1.02 kg, bismuth nitrate _{[Bi (NO 3) 3 · 5H} 2 O ] 0.25 kg, cerium nitrate _{[Ce (NO 3) 3 · 6H} 2 O ] was added 0.068Kg, with stirring It heated at 90 degreeC for 2.5 hours, and was set as the aqueous liquid mixture A-1.
0.50 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.74 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.18 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added and stirred and mixed at 50 ° C. for 1 hour, and then aqueous liquid B-1 was added. Furthermore, a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 60 m / s ² and f = 2.24. In addition, Bi was used for calculation of the mass% of Mo and Sb, assuming that BiO1.5 and Ce would form CeO2.
(Evaluation of catalyst performance)
When the performance in the ammoxidation reaction of the catalyst obtained from the calcining tube outlet was evaluated 48 hours after the start of calcination as in Example 1, the propane conversion was 90.2% and the acrylonitrile yield was 53.5%. .

(Example 16)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} Ti 0.008 Al 0.01 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
In 21.9 kg of water, 4.67 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.71 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 1.03 kg of O ₃ ] was added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.53 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.82 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixture A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.21 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Subsequently, 0.017 kg of titanium oxide [TiO ₂ ] was stirred and dispersed in 0.19 kg of water, and 0.013 kg of aluminum oxide [Al ₂ O ₃ ] was stirred and dispersed in 0.38 kg of water. Further, a liquid prepared by dispersing 1.72 kg of fumed silica in 24.1 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 52 m / s ² and f = 1.91. Assuming that Ti forms TiO2 and Al forms AlO1.5, it was used for the calculation of the mass% of Mo and Sb.
(Evaluation of catalyst yield)
As in Example 1, when the performance in the ammoxidation reaction of the oxide catalyst obtained from the outlet of the calcining tube was evaluated 48 hours after the start of calcination, the propane conversion was 88.6% and the acrylonitrile yield was 53.1%. there were.

(Example 17)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.23 Nb 0.086 Sb 0.27} Ti 0.008 B 0.05 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
21.8 kg of water, 4.65 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.70 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 1.03 kg of O ₃ ] and 0.082 kg of boric acid [H ₃ BO ₃ ] were added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.53 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.80 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixture A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.20 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Subsequently, a solution obtained by stirring and dispersing 0.017 kg of titanium oxide [TiO ₂ ] in 0.19 kg of water was added, and further a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added. Thus, a raw material preparation liquid was obtained.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 61 m / s ² and f = 2.25. Assuming that Ti forms TiO2 and B forms BO1.5, it was used to calculate the mass% of Mo and Sb.
(Catalyst performance evaluation)
As in Example 1, when the performance in the ammoxidation reaction of the oxide catalyst obtained from the outlet of the calcining tube was evaluated 48 hours after the start of calcination, the propane conversion was 88.7% and the acrylonitrile yield was 53.0%. there were.

(Example 18)
Composition formula was produced by the silica-supported catalyst represented by _{Mo 1 V 0.25 Nb 0.086 Sb 0.24} Ce 0.008 O n / 43 wt% -SiO ₂ as follows.
(Preparation of raw material mixture)
24.1 kg of water, 4.72 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.78 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 0.93 kg of O ₃ ] and 0.094 kg of cerium nitrate [Ce (NO ₃ ) ₃ .6H ₂ O] were added and heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
To 3.86 kg of the niobium raw material liquid, 0.52 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 8.49 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Further, 1.09 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Furthermore, a liquid in which 1.72 kg of fumed silica was dispersed in 24.1 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 58 m / s ² and f = 2.16. Note that Ce was used to calculate the mass% of Mo and Sb, assuming that CeO2 was formed.
(Evaluation of catalyst performance)
When the performance in the ammoxidation reaction of the oxide catalyst obtained from the outlet of the calcining tube was evaluated 48 hours after the start of calcination as in Example 1, the propane conversion was 88.3% and the acrylonitrile yield was 53.1%. there were.

(Example 19)
A silica-supported catalyst having a composition formula of Mo ₁ V _0.23 Nb _0.086 Sb _0.27 O _n / 50 mass% -SiO ₂ was produced as follows.
(Preparation of raw material mixture)
19.3 kg of water, 4.12 kg of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 0.62 kg of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ 0.92 kg of O ₃ ] was added, and the mixture was heated at 90 ° C. for 2.5 hours with stirring to obtain an aqueous mixture A-1.
0.45 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added to 3.37 kg of the niobium raw material liquid. The liquid temperature was maintained at about 20 ° C., and the mixture was stirred and mixed to obtain an aqueous liquid B-1.
After cooling the obtained aqueous mixed liquid A-1 to 70 ° C., 9.05 kg of silica sol containing 30.4% by mass as SiO ₂ was added. Furthermore, 1.06 kg of hydrogen peroxide containing 30% by mass as H ₂ O ₂ was added, and after stirring and mixing at 50 ° C. for 1 hour, aqueous liquid B-1 was added. Furthermore, a liquid in which 2.25 kg of fumed silica was dispersed in 31.5 kg of water was added to obtain a raw material preparation liquid.
This process was repeated three times to prepare a total of about 30 kg of raw material preparation solution, which was subjected to the following “preparation of dry catalyst precursor” step and “calcination” step.
(Preparation of dry catalyst precursor)
Spray drying was performed in the same manner as in Example 1 to obtain a dry catalyst precursor.
(Baking)
Firing was performed in the same manner as in Example 2 to obtain an oxide catalyst. The vibration acceleration in the firing step was 65 m / s ² and f = 2.70.
(Evaluation of catalyst yield)
When the performance in the ammoxidation reaction of the catalyst obtained from the calcining tube outlet was evaluated 48 hours after the start of calcination by the same method as in Example 1, the propane conversion was 90.2% and the acrylonitrile yield was 53.7%. Met.
Tables 1 and 2 show the conditions in the firing steps of Examples and Comparative Examples, the composition of the obtained oxide catalyst, the propane (PN) conversion rate, and the acrylonitrile (AN) yield.

From the above results, the manufacturing method of the present embodiment (Examples 1 to 19) applies an impact (striking) to the firing tube with vibration acceleration according to a specific relational expression using a hammer or an air knocker in the firing step. Thus, it was possible to remarkably reduce the sticking generated in the calcining tube, and as a result, it was possible to efficiently produce a catalyst having excellent performance in a large amount.
Further, since the oxide catalyst obtained by the production method of the present embodiment has excellent catalytic performance, the corresponding acrylonitrile can be obtained in a high yield by using it in the gas phase catalytic ammoxidation reaction of propane. It was possible to manufacture stably.
On the other hand, the production method of Comparative Example 1 was inferior in performance of the obtained oxide catalyst because the firing temperature was lower than the melting point of the metal oxide of the catalyst constituent element.
Moreover, since the impact applied to the firing tube in the firing process is weak in the manufacturing method of Comparative Example 2, the firing temperature is lowered by adhering a large amount of fixed matter to the inner wall of the firing tube and deteriorating the heat transfer into the firing tube. The problem that occurred. Furthermore, after a long time, the sticking to the calcining tube further increased and the yield of the catalyst was greatly reduced. In the production method of Comparative Example 3, since the impact applied to the calcination tube in the calcination step is strong, the flow of the catalyst or catalyst precursor in the calcination tube is probably disturbed, and the catalyst cannot be calcined at a desired calcining time and / or calcining temperature. Performance declined.

According to the present invention, it is possible to remarkably reduce the sticking generated in the firing tube in the step of firing the catalyst precursor, and as a result, it is possible to efficiently produce a catalyst having excellent performance in a large amount. It becomes.
Since the oxide catalyst obtained by the production method of the present invention has excellent catalytic performance, the corresponding unsaturated carboxylic acid or unsaturated nitrile (for example, (meth) acrylic acid, ( It has industrial applicability as an oxide catalyst when producing (meth) acrylonitrile).

Claims (14)

A method for producing an oxide catalyst used in a reaction for synthesizing an unsaturated acid or an unsaturated nitrile by gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction of propane or isobutane,
Supplying a catalyst precursor containing Mo and Sb to a firing tube, and firing at a temperature equal to or higher than the melting point of Sb ₂ O ₅ ;
Comprises a step of applying an impact to the calcining tube in the firing step,
In the step of applying the impact, the following formula f = (vibration acceleration) / (A + B)
(In the formula, vibration acceleration: vibration acceleration (m / s ² ) of impact applied to the calcined tube, A: mass% of Mo in the oxide catalyst, B: mass% of Sb in the oxide catalyst)
A method for producing an oxide catalyst, wherein f is represented by 0.08 ≦ f ≦ 50.   The method for producing an oxide catalyst according to claim 1, wherein f satisfies 0.1 ≦ f ≦ 40.   The method for producing an oxide catalyst according to claim 1, wherein the f satisfies 0.2 ≦ f ≦ 30.   The method for producing an oxide catalyst according to any one of claims 1 to 3, wherein the calcination step includes pre-stage calcination and main calcination performed after the pre-stage calcination.   The manufacturing method of the oxide catalyst of Claim 4 which performs the said main calcination in the temperature range of 550-800 degreeC.   The method for producing an oxide catalyst according to claim 4 or 5, wherein the pre-stage calcination is performed in a temperature range of 250 to 400 ° C, and the main calcination is performed in a temperature range of 580 to 750 ° C.   The method for producing an oxide catalyst according to any one of claims 4 to 6, wherein an impact is applied to the firing tube in the main firing.   The method for producing an oxide catalyst according to any one of claims 1 to 7, wherein an impact is applied to the calcining tube at a frequency of once every 1 second or more and 1 hour or less.   The method for producing an oxide catalyst according to any one of claims 1 to 8, wherein an impact is applied to the calcining tube at a frequency of once every 1 second or more and 30 minutes or less.   The method for producing an oxide catalyst according to any one of claims 1 to 9, wherein the firing tube is fired while rotating.   The method for producing an oxide catalyst according to any one of claims 1 to 10, wherein a catalyst precursor is continuously supplied to the calcining tube and calcined by continuous calcining.   When the oxide catalyst contains Mo, V, and Nb, and the atomic ratios of V and Nb per Mo atom are a and b, respectively, 0.1 ≦ a ≦ 1, 0.01 ≦ b ≦ 1 The manufacturing method of the oxide catalyst of any one of Claims 1-11 satisfy | filled. Wherein the oxide catalyst is carried on silica, with respect to the total mass of mass the silica and the oxide catalyst of the silica is 10 to 80 mass% in terms of SiO _2, any one of claims 1 to 12, A process for producing the oxide catalyst according to claim 1.   A propane or isobutane is brought into contact with the oxide catalyst obtained by the production method according to any one of claims 1 to 13 and subjected to a gas phase catalytic oxidation or a gas phase catalytic ammoxidation reaction. Method for producing saturated nitrile.