CN211384878U

CN211384878U - Apparatus for producing oxide catalyst

Info

Publication number: CN211384878U
Application number: CN201921413569.5U
Authority: CN
Inventors: 远藤聪; 加藤高明
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp; Asahi Chemical Industry Co Ltd
Priority date: 2018-08-28
Filing date: 2019-08-28
Publication date: 2020-09-01
Anticipated expiration: 2029-08-28
Also published as: JP2020032403A; CN110860253A; CN110860253B; JP7216620B2

Abstract

An object of the utility model is to provide a can improve oxide catalyst's the manufacturing installation of oxide catalyst of the rate of recovery of oxide catalyst. An apparatus for producing an oxide catalyst used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, the apparatus comprising: a metering tank for metering the raw material; a mixing tank in which the metered raw materials are mixed; and a pipe for flowing the metered raw material from the metering tank to the mixing tank, wherein the pipe is connected to a lower portion of the metering tank and a side wall portion of the mixing tank, and a connection direction of the pipe to the mixing tank is inclined by 30 ° to 90 ° with respect to a direction opposite to a direction of gravity.

Description

Apparatus for producing oxide catalyst

Technical Field

The utility model relates to a manufacturing installation of oxide catalyst.

Background

Unsaturated nitriles are generally produced by a vapor phase catalytic oxidation reaction or a vapor phase catalytic ammoxidation reaction (hereinafter, simply referred to as "oxidation reaction") using an olefin such as propylene or isobutylene or an alkane such as propane or isobutane as a raw material. In the oxidation reaction, an oxide catalyst is used, and from the viewpoint of production efficiency of the oxide catalyst, many production apparatuses of the oxide catalyst have been studied.

For example, patent document 1 discloses a catalyst production apparatus including: a mixing tank for mixing an aqueous mixed solution containing a Mo compound, a V compound, and a Nb compound; a dryer that performs spray drying on the aqueous mixed solution; a pipe connected to the dryer so that the aqueous mixture can be supplied from the tank; and a heater for heating the aqueous mixed liquid in the mixing tank and/or the piping, wherein the piping includes a filter for filtering the aqueous mixed liquid. This document discloses that, by having the above-described structure, a solid material and/or a gelled material can be removed, and as a result, clogging of piping and a dryer can be prevented.

Documents of the prior art

Patent document

Patent document 1: WO2012/081578 pamphlet (Japanese patent No. 5646651)

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

However, in this document, no research has been conducted on a production apparatus capable of improving the recovery rate of the oxide catalyst.

Therefore, an object of the present invention is to provide an apparatus for producing an oxide catalyst, in which the recovery rate of the oxide catalyst can be improved, and clogging of a drying device can be suppressed as necessary while suppressing clogging of piping, thereby improving continuous productivity. Further, the manufacturing apparatus of the present invention does not necessarily include a drying apparatus.

Means for solving the problems

In order to solve the above problems, the present inventors have made an intensive study on an apparatus for producing an oxide catalyst, which comprises a measuring tank, a mixing tank, and a pipe connecting the measuring tank and the mixing tank. As a result, the following problems were found: in such an apparatus, when the raw material (measured raw material) measured by the measuring tank is discharged into the mixing tank, the discharge rate is high, and therefore the measured raw material is likely to splash and adhere (fix) to the wall surface of the mixing tank, the content in the mixing tank, and the like, which causes a decrease in the recovery rate of the oxide catalyst. Also, the following problems have been found: the raw material liquid or mixed liquid adhering to the wall surface of the mixing tank, the content of the mixing tank, and the like is solidified, and the pipes and the drying device are clogged with the peeled solid matter. As a result of further intensive studies, the present inventors have found that the above-described problems can be solved by providing a specific structure for the connection structure between the pipe and the measuring tank and the connection structure between the pipe and the mixing tank, and have completed the present invention.

Namely, the present invention is as follows.

(1) An apparatus for producing an oxide catalyst used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, the apparatus comprising: a metering tank for metering the raw material; a mixing tank in which the metered raw materials are mixed; and a pipe for flowing the metered raw material from the metering tank to the mixing tank, wherein the pipe is connected to a lower portion of the metering tank and a side wall portion of the mixing tank, and a connection direction of the pipe to the mixing tank is inclined by 30 ° to 90 ° with respect to a direction opposite to a direction of gravity.

(2) In the apparatus for producing an oxide catalyst according to item (1), a tip end of the pipe on the mixing tank side is positioned in the mixing tank so that the metered raw material can flow down along an inner surface of a side wall portion of the mixing tank.

(3) In the apparatus for producing an oxide catalyst according to item (1) or (2), a protruding length of the pipe from an inner surface of a side wall portion of the mixing tank is 30cm or less.

(4) The apparatus for producing an oxide catalyst according to any one of the above (1) to (3), wherein a difference A-B in height between a position A at a top end of the pipe on the metering tank side and a position B at a top end of the pipe on the mixing tank side is 30cm to 1000cm when the apparatus is in use.

(5) The apparatus for producing an oxide catalyst according to any one of the above (1) to (4), wherein the pipe is connected to a lower portion of the measuring tank so as to be substantially parallel to a direction of gravity, and is bent on the way to the mixing tank so as to be connected to a side wall portion of the mixing tank.

(6) A method for producing an oxide catalyst to be used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, wherein the catalyst production apparatus according to any one of the above (1) to (5) is used in the method for producing an oxide catalyst.

(7) The method for producing an oxide catalyst according to item (6) above, which comprises: a metering step of metering the raw material in the metering tank; an outflow step of flowing the measured raw material into the mixing tank through the pipe; and a mixing step of mixing the metered raw materials flowing out into the mixing tank to obtain a mixture.

(8) In the method for producing an oxide catalyst according to item (6) or (7), a maximum outflow rate of the raw material to be measured at a tip end of the pipe on the mixing tank side is 10 kg/sec or less.

(9) A process for producing an unsaturated acid or an unsaturated nitrile, which comprises supplying a hydrocarbon to a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction to produce an unsaturated acid or an unsaturated nitrile corresponding to the hydrocarbon, wherein the process for producing an unsaturated acid or an unsaturated nitrile comprises using the oxide catalyst obtained by the process according to any one of the above (6) to (8).

(10) The process for producing an unsaturated acid or an unsaturated nitrile according to the above (9), which comprises the steps of: the oxide catalyst is used to react one of propylene, isobutylene, propane, isobutane, molecular oxygen, and ammonia at a temperature in the range of 300 ℃ to 500 ℃.

(11) In the method for producing an unsaturated acid or unsaturated nitrile according to item (10), a molar ratio of the molecular oxygen to the ammonia in the one of propylene, isobutylene, propane and isobutane is 1: 1.5: 0.8-1: 3.5: 1.1.

effect of the utility model

The utility model discloses, can provide one kind can improve the rate of recovery of oxide catalyst and can restrain the jam of piping and drying device and improve the manufacturing installation of oxide catalyst of continuous productivity rate.

Drawings

Fig. 1 is a front view showing an example of an apparatus for producing an oxide catalyst according to the present invention.

Fig. 2 is a front view showing another example of the oxide catalyst manufacturing apparatus according to the present invention.

Fig. 3 is a front view showing still another example of the oxide catalyst manufacturing apparatus according to the present invention.

Description of the reference numerals

1. 1A, 1B, an apparatus for producing an oxide catalyst; 2. a metering tank; 2A, 2B, 2 nd metering tank; 3. a mixing tank; 4. piping; 4A, 2 nd piping; 5. a temperature regulator; 11A, the 1 st connecting part; 11B, 2 nd connecting part.

Detailed Description

Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail with reference to the drawings. The present invention is not limited to the following description, and various modifications can be made within the scope of the present invention. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Unless otherwise specified, the positional relationship such as up, down, left, right, and the like is based on the positional relationship shown in the drawings. The dimensional ratios in the drawings are not limited to the illustrated ratios.

The production apparatus of the present embodiment is an apparatus for producing an oxide catalyst used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, and includes: a metering tank for metering the raw material; a mixing tank in which the metered raw materials are mixed; and a pipe for flowing the measured raw material from the measuring tank to the mixing tank, wherein the pipe is connected to a lower portion of the measuring tank and a side wall portion of the mixing tank, and a connection direction of the pipe to the mixing tank is inclined at 30 ° to 90 ° (preferably 35 ° to 85 °, and more preferably 40 ° to 80 °) with respect to a direction opposite to a gravity direction. In the manufacturing apparatus of the present embodiment, it is preferable that the tip of the pipe on the mixing tank side is located in the mixing tank so that the metered raw material can flow down along the inner surface of the side wall portion of the mixing tank.

In order to produce the oxide catalyst, usually, the raw materials measured in a measuring tank are flowed out to a mixing tank through a pipe, and the measured raw materials are mixed in the mixing tank. In such a mixing step, it is necessary to ensure the accuracy of the composition of the oxide catalyst from the viewpoint of the yield of a target product (for example, unsaturated nitrile) obtained by a vapor-phase catalytic reaction or a vapor-phase catalytic ammoxidation reaction using an oxide catalyst. However, in this step, there is a problem that a part of each metered raw material is easily lost before mixing in the mixing tank. As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that, in an apparatus for producing an oxide catalyst comprising a metering tank, a mixing tank, and a pipe connecting the metering tank and the mixing tank, when a metering material is discharged into the mixing tank, the metering material is splashed and easily adheres (fixes) to a wall surface (for example, an upper wall surface) of the mixing tank, contents of the mixing tank, and the like because of a high discharge rate. As a result of further studies, the present inventors have found that the above-mentioned problems can be solved by making the connection structure between the pipe and the measuring tank and the connection structure between the pipe and the mixing tank a specific structure in order to suppress the adhesion (fixation) of the measured raw material to the wall surface of the mixing tank, the contents, and the like as described above. That is, in the manufacturing apparatus of the present embodiment, the pipe is connected to the lower portion of the measuring tank and the side wall portion of the mixing tank, and the connection direction of the pipe to the mixing tank is inclined by 30 ° to 90 ° with respect to the direction opposite to the direction of gravity. Since the rapid increase in the outflow rate of the raw material to be metered can be suppressed by setting the inclination angle of the piping in the connection direction with the mixing tank to 30 ° or more, the raw material to be metered is less likely to splash at the tip (outlet of the piping) of the piping on the mixing tank side, and the raw material to be metered can be suppressed from adhering (fixing) to the wall surface of the mixing tank or the like. Here, if the distal end position of the pipe on the mixing tank side is set at a predetermined position so as not to protrude excessively from the inner surface of the side wall portion of the mixing tank, the adhesion (fixation) of the metering material to the wall surface of the mixing tank and the like can be further suppressed. In the manufacturing apparatus of the present embodiment, the tip of the pipe on the mixing tank side is positioned in the mixing tank so that the metered raw material can flow down along the inner surface of the side wall portion of the mixing tank, whereby the metered raw material can be further prevented from adhering (fixing) to the wall surface of the mixing tank. As a result, in the production apparatus of the present embodiment, a part of each of the measured raw materials is not easily lost before mixing in the mixing tank, and the recovery rate of the oxide catalyst can be improved while ensuring the accuracy of the composition of the oxide catalyst. Further, clogging of piping and drying devices can be suppressed, and continuous productivity can be improved.

In the present specification, the term "recovery rate of the oxide catalyst" refers to a recovery rate calculated by the method described in the examples described later, and can be calculated by (theoretical recovery amount calculated from the recovery amount/supply amount) × 100.

In the manufacturing apparatus of the present embodiment, the length of protrusion of the pipe from the inner surface of the side wall portion of the mixing tank is preferably 30cm or less, more preferably 15cm or less, and still more preferably 0cm, that is, the pipe does not protrude from the inner surface of the side wall portion of the mixing tank. By setting the projection length to 30cm or less, the metering material flowing out through the pipe tends to be more reliably prevented from adhering (fixing) to the wall surface of the mixing tank, the contents, and the like.

In addition, it is preferable that the distance between the tip of the pipe and the liquid surface of the mixing tank when the liquid amount in the mixing tank is maximized is h1, and the height of the pipe from the bottom surface of the mixing tank at a portion connected to the wall surface of the mixing tank is h2, in the pipe protruding from the inner surface of the side wall portion of the mixing tank is 0.01 < h1/h2 < 1. Further preferably 0.02 < h1/h2 < 0.9. By making h1/h2 greater than 0.01, the following can be prevented: the tip of the pipe becomes dirty and it is difficult to charge the raw material for metering when it is used for a long period of time. When h1/h2 is less than 1, the raw material to be measured flowing out through the pipe tends to be prevented from adhering (fixing) to the wall surface of the mixing tank, the contents, and the like.

The final liquid surface height immediately after the completion of the charging operation of the raw materials into the mixing tank is preferably set to 0.001 < h3/h0 < 0.5, where h0 represents the final liquid surface height of the mixing tank and h3 represents the distance between the portion of the pipe connected to the wall surface of the mixing tank and the final liquid surface height of the mixing tank. Further preferably, 0.002 < h3/h0 < 0.45 is used. By making h3/h0 greater than 0.001, the following can be prevented: the tip of the pipe becomes dirty and it is difficult to charge the raw material for measurement when the pipe is used for a long period of time. When h3/h0 is less than 0.5, the metered raw material adhering to the wall surface of the mixing vessel, the contents, etc. can be washed away by the liquid in the mixing vessel, and the recovery rate of the oxide catalyst can be improved.

Further, h0 is generally equal to the height of the liquid surface at which the liquid amount reaches the maximum.

In the mixing step, the raw materials are generally mixed while being heated or cooled in a mixing tank, and therefore the mixing tank includes a temperature controller. The temperature controller is a general one such as a jacket-like or coil-like one, and is not particularly limited, but preferably includes at least a jacket-like temperature controller. In the case of the jacket-shaped temperature regulator, the measured material flowing out into the mixing tank is prevented from adhering (fixing) to the temperature regulator as compared with the coil-shaped temperature regulator disposed in the mixing tank, and the measured material tends to be less likely to be lost. When the coil-shaped temperature regulator is included, the tip of the pipe on the mixing tank side is preferably positioned in the mixing tank so that the raw material (measured raw material) after measurement does not contact the coil. This can prevent the measured raw material flowing out of the mixing tank from adhering (fixing) to the temperature controller.

In the oxide catalyst production apparatus of the present embodiment, the difference a-B in height between the height position a of the top end of the pipe on the metering tank side and the height position B of the top end of the pipe on the mixing tank side is preferably 30cm to 1000cm, more preferably 35cm to 800cm, and still more preferably 40cm to 500cm, when used. By setting the height difference a-B to 30cm or more, the raw material to be measured does not easily remain in the piping, and the raw material to be measured tends to flow more efficiently to the mixing tank, and by setting the height difference a-B to 1000cm or less, the outflow rate of the raw material to be measured flowing through the piping can be suppressed from increasing, and the raw material to be measured can be further suppressed from adhering (fixing) to the wall surface of the mixing tank.

In the oxide catalyst production apparatus of the present embodiment, it is preferable that the pipe is connected to the lower portion of the measuring tank so as to be substantially parallel to the direction of gravity, and is bent on the way to the mixing tank so as to be connected to the side wall portion of the mixing tank. By connecting the pipe to the lower portion of the measuring tank substantially parallel to the direction of gravity, the raw material to be measured can be more efficiently flowed out into the mixing tank through the pipe.

The flow rate at the time of charging the raw material to be measured at the tip of the pipe is preferably 0.01m/s to 3 m/s. By setting the flow velocity to 0.01m/s or more, the apparatus for producing an oxide catalyst of the present embodiment can shorten the input time and ensure the productivity. By setting the flow rate to 3m/s or less, the apparatus for producing an oxide catalyst of the present embodiment can suppress the adhesion (fixation) of the metering material to the wall surface of the mixing tank, the content, and the like.

The charging time of the raw materials to be measured can be appropriately adjusted by the charging amount, and is preferably 0.01 second to 3 hours. By setting the charging time to 0.01 seconds or more, the apparatus for producing an oxide catalyst of the present embodiment can suppress the adhesion (fixation) of the metering material to the wall surface of the mixing tank, the content, and the like. By setting the input time to be within 3 hours, the productivity of the oxide catalyst production apparatus of the present embodiment can be ensured.

When the raw materials to be measured are charged into the mixing tank through the pipe, the stirring may be temporarily stopped or reduced in the case where the stirring is performed in the mixing tank. The apparatus for producing an oxide catalyst of the present embodiment can suppress the adhesion (fixation) of the metering material to the wall surface of the mixing tank, the content, and the like by temporarily stopping or weakening the stirring at the time of charging.

The present invention includes a method for producing an oxide catalyst used in a vapor phase catalytic oxidation reaction or a vapor phase catalytic ammoxidation reaction, wherein the catalyst production apparatus of the present invention is used in the method for producing an oxide catalyst. The method for producing an oxide catalyst of the present invention includes, for example, the following steps: a metering step of metering the raw material in a metering tank; an outflow step of flowing the measured raw material into the mixing tank through a pipe; and a mixing step of mixing the metering materials flowing out into the mixing tank to obtain a mixture, wherein each of the steps is performed using the apparatus for producing an oxide catalyst of the present invention.

The present invention also includes a method for producing an unsaturated acid or an unsaturated nitrile by a vapor phase catalytic oxidation reaction or a vapor phase catalytic ammoxidation reaction, wherein the catalyst obtained by the catalyst production apparatus or the catalyst production method of the present invention is used in the method for producing an unsaturated acid or an unsaturated nitrile.

(apparatus for producing oxide catalyst 1)

An example of an apparatus for producing an oxide catalyst according to the present embodiment will be described below with reference to fig. 1. The oxide catalyst manufacturing apparatus 1 shown in fig. 1 includes: a metering tank 2 for metering the raw material; a mixing tank 3 for mixing the measured raw materials in the mixing tank 3; and a pipe 4 for discharging the measured raw material from the measuring tank 2 to the mixing tank 3.

(measuring tank 2)

The metering tank 2 is a tank for metering the raw material. In the present specification, "metering" means that the raw materials (components) constituting the oxide catalyst are brought into a predetermined or desired amount.

(mixing tank 3)

The mixing tank 3 is a tank for mixing the raw materials measured by the measuring tank 2. The mixing tank 3 includes a jacket-like temperature regulator 5. The mixing tank 3 includes an outlet (not shown) for discharging the mixed raw materials (mixture). The discharge port is connected to another device (e.g., a filter device) via a pipe. In this example, the temperature controller 5 is a heat exchanger, and includes an introduction pipe (not shown) for introducing a medium such as a heat medium (e.g., warm water) or a refrigerant (e.g., cold water) and an extraction pipe (not shown) for extracting the medium, and the temperature of the raw material to be measured is controlled by circulating the medium inside the temperature controller 5.

(piping 4)

The pipe 4 is connected to the lower portion of the measuring tank 2 substantially in parallel to the direction of gravity, and is bent on the way toward the mixing tank 3 to be connected to the side wall portion of the mixing tank 3, and the tip of the pipe 4 on the mixing tank 3 side is located at a position not protruding from the inner surface of the side wall portion of the mixing tank 3. In this example, the connection direction L2 of the pipe 4 to the mixing tank 3 is inclined by about 75 ° to 85 ° with respect to the direction X opposite to the direction of gravity. In this example, the height difference a-B between the height position a of the top end of the pipe 4 on the metering tank side and the height position B of the top end of the pipe on the mixing tank side is about 150cm to 200 cm.

The operation and effect of the apparatus 1 for producing an oxide catalyst shown in fig. 1 will be described below. First, the piping 4 is connected to the lower portion of the metering tank 2 so as to be substantially parallel to the direction of gravity, whereby the metered raw materials can be efficiently discharged into the mixing tank via the piping 4, and the connection direction of the piping 4 to the mixing tank 3 is inclined by 75 ° to 85 ° with respect to the direction X opposite to the direction of gravity, whereby a rapid increase in the discharge rate of the metered raw materials can be suppressed, and adhesion (fixation) of the metered raw materials to the wall surface of the mixing tank 3 and the like can be suppressed. Further, since the tip of the pipe 4 on the mixing tank 3 side does not protrude from the inner surface of the side wall portion of the mixing tank 3, the raw material to be measured flowing out from the pipe 4 flows down along the inner surface of the side wall portion of the mixing tank 3. Therefore, the adhesion (fixation) of the metering material to the wall surface of the mixing tank or the like can be more reliably suppressed. Further, by forming the temperature controller 5 in a jacket shape, the adhesion (fixation) of the measured raw material flowing into the mixing tank to the temperature controller 5 can be reliably suppressed. Further, by setting an upper limit to the height difference a-B between the height position a of the tip end of the pipe on the metering tank side and the height position B of the tip end of the pipe on the mixing tank side, it is possible to suppress an increase in the outflow rate of the metering material flowing through the pipe, and to suppress the metering material from adhering (fixing) to the wall surface of the mixing tank 3, and the like. Further, by setting the lower limit to the height difference a-B, the metered raw material is less likely to remain in the piping, and the metered raw material can be made to flow into the mixing tank 3 more efficiently.

The apparatus for producing an oxide catalyst according to the present embodiment is not limited to the apparatus for producing an oxide catalyst 1 shown in fig. 1, and may be configured as follows, and is not particularly limited, and includes: a metering tank for metering the raw material; a mixing tank in which the measured raw materials are mixed; and a pipe for flowing the measured raw material from the measuring tank to the mixing tank, wherein the pipe is connected to a lower portion of the measuring tank and a side wall portion of the mixing tank, and a connection direction of the pipe to the mixing tank is inclined by 30 ° to 90 ° with respect to a direction opposite to a direction of gravity.

(measuring tank)

In the apparatus 1 for producing an oxide catalyst shown in fig. 1, the number of the measuring tanks 2 is 1, but in the apparatus for producing an oxide catalyst of the present embodiment, the number of the measuring tanks may be 1 or a plurality of tanks.

(modification 1)

When the number of the measuring tanks is plural, the plural measuring tanks may be independent of each other and connected to the mixing tank via a pipe. When the number of measuring tanks is two, for example, as in the manufacturing apparatus 1A shown in fig. 2, the 2 nd measuring tank 2A is further disposed on the right side in the left-right direction, and the 2 nd pipe 4A connects the lower portion of the 2 nd measuring tank 2A and the side wall portion of the mixing tank 3. In this example, the manufacturing apparatus 1A has a shape symmetrical with respect to the central axis in the normal cross section of the mixing tank 3, but the manufacturing apparatus of the present embodiment may have a shape asymmetrical with respect to the central axis in the normal cross section of the mixing tank.

(modification 2)

In addition, when the number of the measuring tanks is plural, the plural measuring tanks may be connected to the mixing tank via the pipe so as to share 1 pipe. When the number of measuring tanks is two, for example, as in the manufacturing apparatus 1B shown in fig. 3, the apparatus may further include a 2 nd measuring tank 2B, and the 1 st connection part 11A and the 2 nd connection part 11B of the pipe 4, which are connected to the lower part of the measuring tank 2 and the lower part of the 2 nd measuring tank 2B, may be joined to the side wall part of the mixing tank 3 while heading toward the mixing tank 3.

The material of the measuring groove is not particularly limited, but at least the inner surface of the measuring groove is preferably a material (for example, fluorocarbon resin, glass, or silicone resin) capable of reducing friction of the inner surface. This can further reduce the adhesion (fixation) of the raw material to the inner surface of the measuring tank.

(mixing tank)

In the oxide catalyst production apparatus of the present embodiment, the mixing tank does not necessarily have to include a temperature controller, and may or may not include other temperature control devices (for example, a heater, a heat exchanger having a form other than a coil form or a jacket form, and the like). In the oxide catalyst production apparatus of the present embodiment, if the mixing tank includes the jacket-like temperature regulator, the adhesion (fixation) of the metering material flowing out into the mixing tank to the temperature regulator can be reliably suppressed, and the loss of the metering material is less likely to occur, which is preferable. The jacket-like temperature regulator described here is not limited to the temperature regulator shown in fig. 1 as long as it has a jacket-like form and can perform temperature regulation (temperature control). Further, a jacket-like temperature control device and a coil-like temperature control device may be combined.

The material of the mixing tank is not particularly limited, but at least the inner surface of the mixing tank is preferably a material (for example, fluorocarbon resin, glass, and silicone resin) capable of reducing friction of the inner surface. This can further reduce the adhesion (fixation) of the raw material to the inner surface of the mixing tank.

The mixing tank of the present embodiment may further include, as necessary: a stirring device for stirring the metered raw materials; and a cleaning device for cleaning the inside of the mixing tank.

(piping)

The connection form of the pipe to the measuring tank and the mixing tank may be any connection form as long as the connection direction of the pipe to the mixing tank is inclined at a specific angle with respect to the direction opposite to the direction of gravity, and it is not always necessary to connect the pipe to the lower portion of the measuring tank so as to be substantially parallel to the direction of gravity as in the pipe 4 shown in fig. 1. For example, the pipe may be connected to the lower portion of the measuring tank so that the connection direction of the pipe to the measuring tank is inclined by more than 30 ° with respect to the direction of gravity.

The tip of the pipe on the mixing tank side is preferably located in the mixing tank so that the raw material to be metered can flow down along the inner surface of the side wall of the mixing tank, but it is not always necessary to locate the pipe at a position not protruding from the inner surface of the side wall of the mixing tank as in the pipe 4 shown in fig. 1.

The material of the pipe is not particularly limited, but from the viewpoint of suppressing adhesion (fixation) of the metering raw material (particularly, the powder raw material), a material (for example, a fluorocarbon resin) capable of reducing friction on the inner surface thereof is preferable. In addition, a hammer (japanese patent No. ノッカー) and/or a vibrator (japanese patent No. バイブレーター) may be provided in the pipe in order to peel off the metering material (particularly, the powdery material) adhered (fixed) to the pipe.

In the oxide catalyst production apparatus of the present embodiment, a pump (for example, a screw pump, a uniaxial eccentric screw pump, a centrifugal pump, and a piston pump) may be disposed in the middle of the pipe from the viewpoint of controlling the outflow rate of the metering material flowing out to the mixing tank.

The apparatus for producing an oxide catalyst of the present embodiment may further include, as necessary: a filtering device for filtering a mixture obtained by mixing and measuring the raw materials in the mixing tank; a drying device (e.g., a spray drying device) for drying the mixture filtered by the filtering device; and a roasting device (e.g., a rotary furnace, a flow roasting furnace) for roasting the mixture dried by the drying device.

(oxide catalyst and raw Material therefor)

The oxide catalyst of the present embodiment (hereinafter also simply referred to as "catalyst") is not particularly limited, and is preferably a catalyst containing at least molybdenum (Mo) element, but from the viewpoint of more effectively and reliably exhibiting the effects of the present invention, the oxide catalyst of the present embodiment is preferably a catalyst used in a production process for producing a corresponding unsaturated acid or unsaturated nitrile by supplying a hydrocarbon to a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction. More preferably, the hydrocarbon is selected from the group consisting of propane, isobutane, propylene and isobutene. Further, the unsaturated acid is preferably acrylic acid and/or methacrylic acid. Also, the above-mentioned unsaturated nitrile is preferably acrylonitrile and/or methacrylonitrile.

Examples of the metal element that can be contained in the catalyst other than molybdenum include Bi (bismuth), Fe (iron), V (vanadium), Sb (antimony), Te (tellurium), Nb (niobium), W (tungsten), Ni (nickel), and Co (cobalt). These can be used alone in 1 kind or in combination of two or more kinds. The catalyst is preferably a composite oxide catalyst containing two or more of the above-described metal elements.

As the other elements, the catalyst may contain 1 or more elements selected from the group consisting of La (lanthanum), Ce (cerium), Pr (praseodymium), Yb (ytterbium), Y (yttrium), Sc (scandium), Sr (strontium), Ba (barium), Ca (calcium), Mg (magnesium), Zn (zinc), Mn (manganese), Al (aluminum), Ga (gallium), In (indium), Cr (chromium), Ru (ruthenium), Rh (rhodium), Pd (palladium), Os (osmium), Ir (iridium), Pt (platinum), Na (sodium), K (potassium), Rb (rubidium), and Cs (cesium).

More specifically, the catalyst may be a composite oxide having 1 or more kinds of composition selected from the group consisting of compositions represented by the following formulae (1), (2), and (3). Wherein, the catalyst represented by the formula (1) is suitable for the gas-phase catalytic oxidation reaction and the gas-phase catalytic ammoxidation reaction of propane or isobutane, and the catalyst represented by the formula (2) and the formula (3) is suitable for the gas-phase catalytic oxidation reaction and the gas-phase catalytic ammoxidation reaction of propylene or isobutylene.

Mo₁V_aSb_bNb_cW_dZ_eO_n...(1)

In the formula (1), the component Z represents at least 1 or more element selected from La, Ce, Pr, Yb, Y, Sc, Sr and Ba, a, b, c, d, e and n represent the atomic ratio of each element to Mo1 atom, and are 0.1. ltoreq. a.ltoreq.0.4, 0.1. ltoreq. b.ltoreq.0.4, 0.01. ltoreq. c.ltoreq.0.3, 0. ltoreq. d.ltoreq.0.2, 0. ltoreq. e.ltoreq.0.1, and n is the number of oxygen atoms satisfying the valence of the constituent element other than oxygen.

Mo₁₂Bi_aFe_bJ_cD_dE_eL_fG_gO_n...(2)

Wherein In formula (2), J represents 1 or more elements selected from the group consisting of Ni, Co, Mn, Zn, Mg, Ca, Sr and Ba, D represents 1 or more elements selected from the group consisting of Cr, W, V, Nb, B, Al, Ga, In, P, Sb and Te, E represents 1 or more elements selected from the group consisting of rare earth elements, L represents 1 or more elements selected from the group consisting of Ru, Rh, Pd, Os, Ir and Pt, G represents 1 or more elements selected from the group consisting of Na, K, Rb and Cs, a, B, c, D, E, f, G and n represent the atomic ratio of bismuth (Bi), iron (Fe), J, D, E, L, G and oxygen (O) to molybdenum (Mo)12 atoms, a is 0.05 to 7, B is 0.1 to 7, c is 0 to 12, D is 0 to 5, e is 0 to 5, f is 0 to 0.2, g is 0.01 to 5, and n is the number of oxygen atoms satisfying the valence of the constituent element other than oxygen.

Mo₁₂(Bi_1-aCe_a)_bFe_cX_dT_eZ_fO_g...(3)

Here, in formula (3), X represents 1 or more elements selected from the group consisting of Ni and Co, T represents 1 or more elements selected from the group consisting of Mg, Ca, Zn, Sr and Ba, Z represents 1 or more elements selected from the group consisting of K, Rb and Cs, a represents a relative atomic ratio of Ce to the total of Bi and Ce, is 0.2 or more and 0.8 or less, b represents an atomic ratio of the total of Bi and Ce to 12 atoms of molybdenum (Mo), is 0.5 or more and 1.5 or less, c represents an atomic ratio of Fe to 12 atoms, is 0.1 or more and 3 or less, d represents an atomic ratio of X to 12 atoms, is 0.1 or more and 9.5 or less, e represents an atomic ratio of T to 12 atoms of Mo, is 0 or more and 9.5 or less, f represents an atomic ratio of Z to 12 atoms of Mo, is 0.01 or more and 2 or less, g represents an atomic ratio of oxygen to 12 atoms of Mo, is the number of oxygen atoms required to satisfy the valence requirements of the other elements present.

The catalyst in the present embodiment may be a silica-containing catalyst, and more specifically, may be a silica-supported catalyst supported on silica. When the catalyst contains the composite oxide and silica, the content of silica contained in the catalyst, preferably the content of carrier silica, is SiO from the viewpoint of enhancing the strength of the catalyst₂Conversion to the contents of composite oxide and dioxideThe total mass of the silicon catalyst is preferably 20 mass% or more, and from the viewpoint of providing sufficient activity, it is preferably 70 mass% or less. More preferably, the content is 40 mass% or more and 65 mass% or less with respect to the entire mass of the catalyst.

The raw materials may be in the form of a powder and flow out to the mixing tank through a pipe, or may be in the form of an aqueous solution (e.g., a suspension) obtained by adding the raw materials to an aqueous solvent (e.g., water, an aqueous nitric acid solution, and aqueous ammonia) and flow out to the mixing tank through a pipe.

(method for producing oxide catalyst)

The method for producing an oxide catalyst according to the present embodiment is a method for producing an oxide catalyst used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, wherein the method for producing an oxide catalyst according to the present embodiment uses an apparatus for producing an oxide catalyst according to the present embodiment, and the method for producing an oxide catalyst includes, for example, the steps of: a metering step of metering the raw material in a metering tank; an outflow step of flowing the measured raw material into the mixing tank through a pipe; and a mixing step of mixing the metered raw materials flowing out into the mixing tank to obtain a mixture. The method for producing an oxide catalyst according to the present embodiment may further include: a filtering step of filtering the mixture obtained in the mixing step; a drying step of drying the mixture filtered in the filtering step to obtain a dried product; and a calcination step of calcining the dried product obtained in the drying step to obtain an oxide catalyst.

In the method for producing an oxide catalyst according to the present embodiment, for example, any of the metering step, the outflow step, and the mixing step is carried out using the apparatus for producing an oxide catalyst according to the present embodiment. The piping is connected to the lower portion of the measuring tank and the side wall portion of the mixing tank, and the connection direction of the piping to the mixing tank is inclined by 30 ° to 90 ° with respect to the direction opposite to the direction of gravity. Since the rapid increase in the outflow rate of the raw material to be weighed can be suppressed by setting the inclination angle of the connection direction of the piping to the mixing tank to 30 ° or more, even if the raw material to be weighed is allowed to flow out through the piping in the outflow step, the raw material to be weighed can be suppressed from adhering (fixing) to the wall surface of the mixing tank or the like. In the manufacturing method of the present embodiment, for example, the tip of the pipe on the mixing tank side is positioned in the mixing tank so that the metered raw material can flow down along the inner surface of the side wall portion of the mixing tank, whereby the metered raw material can be more reliably prevented from adhering (fixing) to the wall surface of the mixing tank in the outflow step. As a result, in the production method of the present embodiment, a part of each of the measured raw materials is not easily lost before mixing in the mixing tank, and the recovery rate of the obtained oxide catalyst can be improved while ensuring the accuracy of the composition of the oxide catalyst.

(measurement Process)

In the measuring step of the present embodiment, the raw material is measured by the measuring tank. The raw materials may be the above-mentioned compounds, and the amounts of the compounds may be adjusted by this step, or an aqueous solvent may be added to the compounds to prepare an aqueous solution. In this step, 1 measuring tank may be used to measure each compound as a raw material collectively or sequentially, or a plurality of measuring tanks may be used to measure each compound as a raw material.

(outflow step)

In the outflow step, the metered raw material is caused to flow out into the mixing tank through the pipe. The maximum outflow velocity of the metering material at the tip of the pipe on the mixing tank side is preferably 10 kg/sec or less, and more preferably 5 kg/sec or less. This can further suppress adhesion of the raw material to the wall surface of the mixing tank, the contents of the mixing tank, and the like.

(mixing Process)

In the mixing step, the metered raw materials flowing out into the mixing tank are mixed to obtain a mixture (e.g., a mixed solution). In this step, the raw materials may be mixed while adjusting the temperature of the raw materials to be measured using a temperature adjuster such as a jacket-shaped temperature adjuster, or the raw materials may be mixed while stirring the raw materials to be measured using a stirring device.

(filtration step)

In the filtration step, the mixture (for example, a mixed solution) obtained in the mixing step is filtered. In this step, solid dirt and gel components can be removed from the mixture. As a filtration method, a method of passing the mixture through a known filter or the like can be cited.

(drying Process)

In the drying step, the mixture (for example, a mixed solution) obtained in the filtering step is dried to obtain a dried product. Examples of the drying method include a spray drying method and a steam drying method, and the spray drying method is generally used in many cases. As a specific example of the spray drying method, the contents described in paragraphs 0091 to 0109 of patent document 1 can be referred to.

(baking Process)

In the calcination step, the dried product obtained in the drying step is calcined to obtain an oxide catalyst. More specifically, the contents described in paragraphs 0110 to 0128 of patent document 1 can be referred to.

The method for producing an oxide catalyst according to the present embodiment may further include a removal step of removing the protrusions from the oxide catalyst obtained in the calcination step. When the protrusions existing on the surface of the oxide catalyst particles are removed by this step, sufficient fluidity can be ensured when the fluidized bed reaction is carried out using the oxide catalyst, and the yield of the target product can be further improved.

The oxide catalyst obtained by the production method of the present embodiment can be preferably used for producing an unsaturated acid or an unsaturated nitrile, for example. That is, the present embodiment provides a method for producing an unsaturated acid or an unsaturated nitrile, which produces an unsaturated acid or an unsaturated nitrile corresponding to a hydrocarbon by supplying the hydrocarbon to a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction, wherein in the method for producing an unsaturated acid or an unsaturated nitrile, the oxide catalyst obtained by the production method of the present embodiment is used.

More specifically, the method comprises a reaction step of reacting one of an olefin such as propylene or isobutylene, an alkane such as propane or isobutane, molecular oxygen, and ammonia in the presence of the oxide catalyst to produce an unsaturated acid or an unsaturated nitrile corresponding to the hydrocarbon as a raw material. The gas-phase catalytic oxidation reaction or the gas-phase catalytic ammoxidation reaction of propane, isobutane or the like can be carried out by a known method.

The reaction temperature in the step is preferably 300 to 500 ℃, more preferably 400 to 480 ℃ from the viewpoint that the reaction product can be obtained with high yield.

In the process, the reaction pressure is preferably atmospheric pressure or slightly increased pressure.

In the above step, the molar ratio of one of propylene, isobutylene, propane and isobutane, molecular oxygen and ammonia is preferably 1: 1.50: 0.80-1: 3.50: 1.10, more preferably 1: 2.80: 0.90-1: 3.30: 1.08.

the production method of the present embodiment may include a step of purifying the reaction product obtained in the above reaction step to separate the corresponding unsaturated acid or unsaturated nitrile.

Examples

The present embodiment will be described in detail below with reference to examples, but the present embodiment is not limited to the following examples.

In each of examples 1 and 2 and comparative examples 1 to 4, the propane conversion and the acrylonitrile yield were defined by the following formulae.

Propane conversion (%) (number of moles of propane reacted)/(number of moles of propane supplied) × 100 acrylonitrile yield (%) (number of moles of acrylonitrile produced)/(number of moles of propane supplied) × 100

In each of examples 1 to 4 and comparative examples 1 to 6, production apparatuses a to F each including a measuring tank, a mixing tank, and a pipe connecting the measuring tank and the mixing tank were used.

Manufacturing apparatus a:

a manufacturing apparatus similar to the manufacturing apparatus 1 shown in fig. 1 is used except that the connection direction of the pipe to the mixing tank is inclined at an inclination angle (hereinafter, also simply referred to as "inclination angle") of 90 ° with respect to the direction X opposite to the gravity direction.

Manufacturing apparatus B:

the manufacturing apparatus is the same as the manufacturing apparatus 1 shown in fig. 1 except that the inclination angle is 30 °.

Manufacturing apparatus C:

the manufacturing apparatus is the same as the manufacturing apparatus 1 shown in fig. 1 except that the pipe is not connected to the side wall portion of the mixing tank but is connected to the upper portion (upper wall portion) of the mixing tank.

Manufacturing device D:

the manufacturing apparatus is the same as the manufacturing apparatus 1 shown in fig. 1 except that the inclination angle is 20 °.

Manufacturing apparatus E:

the manufacturing apparatus was the same as the manufacturing apparatus 1 shown in FIG. 1 except that the inclination angle was 80 degrees and the length of protrusion of the pipe from the inner surface of the side wall of the mixing tank was 40 cm.

Manufacturing apparatus F:

the manufacturing apparatus was the same as the manufacturing apparatus 1 shown in fig. 1 except that the inclination angle was 20 °, and the tip of the pipe on the mixing tank side was located in the mixing tank so that the measured raw material was in contact with the temperature controller.

(example 1)

Aqueous stock solution (I)

A niobium raw material solution was prepared by the following method. First, 76.33kg of Nb-containing alloy was mixed with 500kg of water₂O₅80.2 mass% of niobic acid and 290.2kg of oxalic acid dihydrate [ H ]₂C₂O₄·2H₂O ]. The oxalic acid/niobium molar ratio was supplied as 5.0, and the niobium concentration was supplied as 0.532 (mol-Nb/kg-liquid). This liquid was heated and stirred at 95 ℃ for 1 hour to obtain an aqueous solution in which the Nb compound was dissolved. Standing the aqueous solution, cooling with ice, filtering off solid by suction filtration to obtain uniform Nb compoundAn aqueous solution of (a). The same operation was repeated a plurality of times, and the obtained aqueous solutions of Nb compounds were combined to obtain a niobium raw material solution. The oxalic acid/niobium molar ratio of the niobium raw material solution was 2.4 by the following analysis.

In a crucible, 10g of this niobium raw material solution was precisely weighed, dried at 95 ℃ overnight, and then heat-treated at 600 ℃ for 1 hour to obtain 0.8323g of Nb₂O₅. As a result, the niobium concentration was 0.627 (mol-Nb/kg-liquid). In a 300mL glass beaker, 3g of this niobium raw material solution was precisely weighed, 200mL of hot water at about 80 ℃ was added, and then 1: 1 sulfuric acid 10 mL. While maintaining the resulting solution at a liquid temperature of 70 ℃ on a hot stirrer, 1/4 equivalent KMnO was used under stirring₄Titration was performed. Will be composed of KMnO₄The weak pale peach color obtained lasted for about 30 seconds or more as an end point. The concentration of oxalic acid is measured by KMnO₄The titration amount of (A) was calculated by referring to the following reaction formula, and the result was 1.50 (mol-oxalic acid/kg).

2KMnO₄+3H₂SO₄+5H₂C₂O₄→K₂SO₄+2MnSO₄+10CO₂+8H₂O

The obtained niobium raw material solution was used as a niobium raw material solution for producing an oxide catalyst described below. The niobium raw material liquid can be prepared by the same method as needed, and the niobium raw material liquid is prepared so as to prevent the niobium raw material liquid used for the aqueous mixed solution from being insufficient. Next, 3.89kg of a niobium solution containing 30 mass% of H was added to 29.4kg of the niobium solution in a separate vessel₂O₂Hydrogen peroxide (c). The aqueous starting material solution (I) was obtained by stirring and mixing while maintaining the liquid temperature at about 20 ℃.

As a production apparatus for the oxide catalyst, a production apparatus a was used. The water was made to reach 100kg by the measuring tank and flowed out into the mixing tank through the piping. Similarly, 30.28kg of ammonium heptamolybdate [ (NH)₄)₆Mo₇O₂₄·4H₂O, 4.214kg ammonium metavanadate [ NH ]₄VO₃5.52kg of antimony trioxide [ Sb ]₂O₃And 372g of cerium nitrate [ Ce (NO)₃)₃·6H₂O ] cerium nitrate aqueous solutions obtained by dissolving them in 26kg of water were discharged into the mixing tank through pipes, respectively. Subsequently, the respective measured raw materials were heated at 95 ℃ for 1 hour while being stirred in a mixing tank to obtain an aqueous raw material solution (I).

The resulting aqueous starting material solution (I) was cooled to 70 ℃ in a mixing tank. Next, the SiO was contained in an amount of 30.2 mass% by using a measuring tank₂The silica sol (2) was 59.9kg, and the silica sol was discharged into the mixing tank through a pipe. Next, the mixture was measured by a measuring tank to contain 30 mass% of H₂O₂The amount of hydrogen peroxide (2) was 6.45kg, and the hydrogen peroxide was discharged into the mixing tank through the piping. Next, the mixture was stirred and mixed in a mixing tank at 55 ℃ for 30 minutes. Next, the total amount of the aqueous raw material liquid (II) and the ammonium metatungstate aqueous solution were adjusted to 2.39kg (purity: 50%) by a measuring tank, and these were flowed out into a mixing tank through a pipe. Then, 14.8kg of fumed silica was dispersed in 214.7kg of water in the metering tank, and the resulting liquid was discharged into the mixing tank through the pipe. In this case, the mixture was aged at 50 ℃ for 1 hour in an atmosphere having a gas-phase oxygen concentration of 18 vol% to obtain an aqueous mixture (III) (viscosity at 50 ℃ C.: 5.0 cp). Further, the stirring was carried out under the condition that Pv was 1.0kW/m³. The values of h1/h2 and h3/h0 are shown in Table 1.

(spray drying of the aqueous mixture obtained in the mixing tank)

Until the end of mixing of the aqueous mixed solution (III), air heated to 210 ℃ and warm water at 50 ℃ adjusted to a supply amount of 80kg/hr were supplied from a nozzle to the spray dryer 120, and the inlet temperature of the dryer 120 was set to 210 ℃ and the outlet temperature was set to 120 ℃.

Immediately after the completion of the mixing of the aqueous mixed liquid (III) in the mixing tank, the liquid supplied to the dryer is switched from the hot water to the aqueous mixed liquid (III) supplied from the mixing tank. The aqueous mixed liquid (III) is circulated through a pipe and is supplied to the dryer through a pump and a filter in this order. The amount of the aqueous liquid mixture (III) supplied to the spray dryer was adjusted so as not to change the outlet temperature, and as a result, the amount of the aqueous liquid mixture (III) supplied was 100 kg/hr. During this time, the outlet temperature was 120. + -. 5 ℃ without major variation. After the spray drying, water was supplied from the dryer to the mixing tank, and the filter was backwashed for 1 hour.

As described above, the operation from the metering step in the metering tank to the backwashing of the filter was repeated for 1 month. The dry product obtained in the course of 1 month was 11.3 tons, and the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 98.0%. During this period, the mixing tank was continuously operated without clogging of the piping until the mixing tank was sprayed by the spray dryer.

(calcination)

The dried product obtained was classified by using a sieve having a pore diameter of 25 μm to obtain a classified product, and in a cylindrical roasting tube made of SUS having an inner diameter of 500mm, a length of 3500mm and a wall thickness of 20mm, 7 baffles having a height of 150mm were provided so as to divide the length of 8 parts of the furnace portion equally, the classified product was allowed to flow through the roasting tube at a rate of 20kg/hr, the roasting tube was rotated at a rate of 4 revolutions per minute under the condition that 600N liters/min of nitrogen gas was allowed to flow, and the temperature of the furnace was adjusted so that the temperature of the roasting tube was raised to 370 ℃ for about 4 hours and kept at 370 ℃ for 3 hours, and the pre-stage roasting was carried out, thereby obtaining a pre-stage roasted product. In another SUS roasting pipe having an inner diameter of 500mm, a length of 3500mm and a wall thickness of 20mm, 7 baffles having a height of 150mm were provided so as to divide the length of the furnace part into 8 equal parts, and the pre-roasted product was circulated at a rate of 15kg/hr while rotating the roasting pipe at a rate of 4 revolutions per minute. At this time, the portion of the baking tube on the side of the previous-stage baked product introduction (the portion not covered with the heating furnace) was subjected to 1-time impact every 5 seconds from a height of 250mm above the baking tube in the direction perpendicular to the rotation axis by a hammer device provided with a hammer having an impact portion tip made of SUS and having a mass of 14kg, and the baking tube was baked while adjusting the heating furnace temperature so as to have a temperature profile in which the temperature of the baking tube was raised to 680 ℃ at 2 ℃/min, the baking tube was baked at 680 ℃ for two hours and the temperature was lowered to 1 ℃/min under the condition that 500N liters/min of nitrogen gas was flowed through the baking tube, thereby obtaining an oxide catalyst.

(removal of protrusions)

50g of an oxide catalyst was charged into a vertical tube (41.6 mm in inner diameter and 70cm in length) having a perforated disk with 3 holes 1/64 inches in diameter at the bottom and a paper filter at the top. The length of the air flow in the direction of the air flow at this time was 52mm, and the average linear velocity of the air flow was 310 m/s. The oxide catalyst obtained after 24 hours was confirmed by SEM, and as a result, the existence of protrusions on the surface of the oxide catalyst was not confirmed.

(ammoxidation reaction)

Using the oxide catalyst obtained above, propane was supplied to the vapor phase ammoxidation reaction by the following method. A Wacker heat-resistant glass fluidized-bed type reaction tube having an inner diameter of 25mm was charged with 35g of an oxide catalyst, the reaction temperature was set to 440 ℃, the reaction pressure was set to normal pressure, and propane was supplied at a contact time of 2.8 (sec. g/cc): ammonia: oxygen: helium-1: 1: 3: 18 in terms of mole ratio. The conversion of propane after the reaction was 90.1%, and the yield of acrylonitrile was 53.5%.

(example 2)

The operation was carried out in the same manner as in example 1 except that the production apparatus a was not used but the production apparatus B was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 11.4 tons, while the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 99.0%. During this period, the mixing tank was continuously operated without clogging of the piping until the mixing tank was sprayed by the spray dryer. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propane after the reaction was 90.5%, and the yield of acrylonitrile was 53.6%.

(example 3)

As a production apparatus for the oxide catalyst, a production apparatus a was used. The SiO was contained in an amount of 30 mass% by using a metering tank₂The amount of the aqueous silica sol (2) was 133.3kg, and the aqueous silica sol was discharged into a mixing tank through a pipe. Similarly, 48.59kg of ammonium heptamolybdate ((NH)₄)₆Mo₇O₂₄·4H₂O) flows out into the mixing tank through a pipe. Stirring the mixtureThe raw materials were each measured to obtain an aqueous raw material liquid (I).

Next, 4.31kg of bismuth nitrate (Bi (NO) was added₃)₃·5H₂O), 14.8kg of ferric nitrate (Fe (NO)₃)₃·9H₂O), 46.47kg of nickel nitrate (Ni (NO)₃)₂·6H₂O) 4.55kg of magnesium nitrate (Mg (NO)₃)₂·6H₂O) and 6.26kg of cerium nitrate (Ce (NO)₃)₃·6H₂O), 0.59kg of rubidium nitrate (RbNO)₃) The resultant was dissolved in 16.6 mass% of 39.67kg of nitric acid in a measuring tank to obtain an aqueous raw material solution (II).

Next, all of the aqueous raw material liquid (II) was discharged into a mixing tank through a pipe and stirred to obtain an aqueous mixed liquid (III). The stirring condition is that Pv is 1.0kW/m³。

(spray drying of the aqueous mixture obtained in the mixing tank)

Until the end of mixing of the aqueous mixed solution (III), air heated to 230 ℃ and warm water at 50 ℃ adjusted to a supply amount of 80kg/hr were supplied from a nozzle to the spray dryer 120, and the inlet temperature of the dryer 120 was set to 230 ℃ and the outlet temperature was set to 110 ℃.

Immediately after the completion of the mixing of the aqueous mixed liquid (III) in the mixing tank, the liquid supplied to the dryer is switched from the hot water to the aqueous mixed liquid (III) supplied from the mixing tank. The aqueous mixed liquid (III) is circulated through a pipe and is supplied to the dryer through a pump and a filter in this order. The amount of the aqueous mixed liquid (III) supplied to the spray dryer was adjusted so as not to vary the outlet temperature, and as a result, the amount of the aqueous mixed liquid (III) supplied was 140 kg/hr. During this time, the outlet temperature was 120. + -. 5 ℃ without major variation. After the spray drying, water was supplied from the dryer to the mixing tank, and the filter was backwashed for 1 hour.

As described above, the operation from the metering step in the metering tank to the backwashing of the filter was repeatedly continued for 1 month. The dry product obtained in the course of 1 month was 29.5 tons, while the theoretical recovery amount calculated from the supply amount was 30.2 tons, and the recovery rate was 98.0%. During this period, the mixing tank was continuously operated without clogging of the piping until the mixing tank was sprayed by the spray dryer. The values of h1/h2 and h3/h0 are shown in Table 1.

(calcination)

The obtained dry powder was held at 200 ℃ for 5 minutes, and heated from 200 ℃ to 450 ℃ at 2.5 ℃/minute and held at 450 ℃ for 20 minutes, thereby carrying out denitration. The obtained denitration powder was calcined at 580 ℃ for two hours to obtain a catalyst.

(vapor phase catalytic ammoxidation of propylene)

The vapor phase catalytic ammoxidation reaction of propylene was carried out in the presence of the obtained catalyst. As a reaction tube used for the vapor phase catalytic ammoxidation of propylene, a pyrex (registered trademark) glass tube having an inner diameter of 25mm, in which 16 pieces of 10-mesh wire gauze were placed at 1cm intervals, was used. The catalyst amount was set to 50g, the reaction temperature was set to 430 ℃ and the reaction pressure was set to 0.17MPa, and a mixed gas (propylene, ammonia, oxygen, helium) containing 9% by volume of propylene was passed through the glass tube. The volume ratio of ammonia to propylene was set so that the specific consumption of sulfuric acid defined by the following formula became 20. + -.10 kg/T-AN. The volume ratio of oxygen to propylene was set so that the oxygen concentration of the reactor outlet gas became 0.2. + -. 0.02 vol%. In addition, by changing the flow rate of the mixed gas, the contact time defined by the following formula can be changed. Thus, the propylene conversion defined by the following formula was set to 99.3 ± 0.2%. The yield of acrylonitrile produced by the reaction is defined by the following formula. The catalyst activity (k η) in the fluidized bed reaction evaluation is defined by the following formula. Further, the reaction time was 20 hours.

Sulfuric acid specific consumption (kg/T-AN) (mass of sulfuric acid (kg) necessary for neutralizing unreacted ammonia)/(production mass of acrylonitrile (T))

Propylene conversion (%) ((consumed propylene (mol))/(supplied propylene (mol)) × 100)

Acrylonitrile (AN) yield (%) ((acrylonitrile (mol) produced))/(propylene (mol) supplied)) × 100

Contact time (sec. g/cm)³)＝(W/F)×273/(273+T)

Here, W, F and T in the equation are defined as follows.

Amount of catalyst (g) filled

F ═ standard state (0 ℃, 1.013 × 10)⁵Pa) of the mixed gas flow rate (Ncc/sec)

Temperature (. degree.C.) of reaction

Kη(Hr^-1) = 3600/(contact time) × ln ((100-propylene conversion)/100)

In the equation, ln represents a natural logarithm. The conversion of propylene after the reaction was 99.0%, and the yield of acrylonitrile was 83.8%.

(example 4)

The operation was carried out in the same manner as in example 3 except that the production apparatus a was not used but the production apparatus B was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 29.8 tons, while the theoretical recovery amount calculated from the supply amount was 30.2 tons, and the recovery rate was 99.0%. During this period, the mixing tank was continuously operated without clogging of the piping until the mixing tank was sprayed by the spray dryer. The values of h1/h2 and h3/h0 are shown in Table 1. In the ammoxidation reaction, the same procedure as in example 3 was followed. The conversion of propylene after the reaction was 99.3%, and the yield of acrylonitrile was 84.1%.

Comparative example 1

The operation was performed in the same manner as in example 1, except that the production apparatus a was not used but the production apparatus C was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 10.9 tons, while the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 95.0%. During the 1 month operation, the amount of liquid delivered to the spray dryer was reduced twice, and therefore the solid matter was present as a result of inspection of the spray dryer inlet piping. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propane after the reaction was 91.0%, and the yield of acrylonitrile was 52.9%.

Comparative example 2

The operation was carried out in the same manner as in example 1 except that the production apparatus a was not used but the production apparatus D was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 11.0 tons, while the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 96.0%. During the operation for 1 month, the amount of liquid fed to the spray dryer was reduced by 1 time, and therefore, the solid matter was present as a result of the inspection of the inlet pipe of the spray dryer. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propane after the reaction was 90.8%, and the yield of acrylonitrile was 52.6%.

Comparative example 3

The operation was performed in the same manner as in example 1, except that the production apparatus a was not used but the production apparatus E was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 10.9 tons, while the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 95.0%. During the 1 month operation, the amount of liquid delivered to the spray dryer was reduced twice, and therefore the solid matter was present as a result of inspection of the spray dryer inlet piping. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propane after the reaction was 90.8%, and the yield of acrylonitrile was 52.7%.

Comparative example 4

The operation was performed in the same manner as in example 1, except that the production apparatus a was not used but the production apparatus F was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 11.0 tons, while the theoretical recovery amount calculated from the supply amount was 11.5 tons, and the recovery rate was 96.0%. During the operation for 1 month, the amount of liquid fed to the spray dryer was reduced by 1 time, and therefore, the solid matter was present as a result of the inspection of the inlet pipe of the spray dryer. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propane after the reaction was 90.9%, and the yield of acrylonitrile was 52.6%.

Comparative example 5

The operation was carried out in the same manner as in example 3 except that the production apparatus a was not used but the production apparatus C was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 28.6 tons, while the theoretical recovery amount calculated from the supply amount was 30.2 tons, and the recovery rate was 95.0%. During the operation for 1 month, the amount of liquid fed to the spray dryer was reduced by 1 time, and therefore, the solid matter was present as a result of the inspection of the inlet pipe of the spray dryer. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propylene after the reaction was 99.1%, and the yield of acrylonitrile was 83.2%.

Comparative example 6

The operation was carried out in the same manner as in example 3 except that the production apparatus a was not used but the production apparatus D was used as a production apparatus for an oxide catalyst. The dry product obtained in the course of 1 month was 28.9 tons, while the theoretical recovery amount calculated from the supply amount was 30.2 tons, and the recovery rate was 96.0%. During the operation for 1 month, the amount of liquid fed to the spray dryer was reduced by 1 time, and therefore, the solid matter was present as a result of the inspection of the inlet pipe of the spray dryer. In order to remove the solid matter, the liquid feeding was temporarily stopped and cleaning was performed. The values of h1/h2 and h3/h0 are shown in Table 1. In addition, the conversion of propylene after the reaction was 99.2%, and the yield of acrylonitrile was 83.1%.

TABLE 1

Claims

1. An apparatus for producing an oxide catalyst used in a vapor-phase catalytic oxidation reaction or a vapor-phase catalytic ammoxidation reaction,

the manufacturing apparatus includes: a metering tank for metering the raw material; a mixing tank in which the metered raw materials are mixed; and a pipe for flowing the measured raw material from the measuring tank to the mixing tank,

the pipe is connected to a lower portion of the measuring tank and a side wall portion of the mixing tank,

the connection direction of the pipe to the mixing tank is inclined by 30 to 90 DEG with respect to the direction opposite to the direction of gravity.

2. The oxide catalyst production apparatus according to claim 1,

the pipe is positioned in the mixing tank so that a tip end thereof on the mixing tank side can cause the metered raw material to flow down along an inner surface of a side wall portion of the mixing tank.

3. The oxide catalyst production apparatus according to claim 1 or 2,

the length of protrusion of the piping from the inner surface of the side wall of the mixing tank is 30cm or less.

4. The oxide catalyst production apparatus according to claim 1 or 2,

when in use, the height difference A-B between the height position A of the top end of the pipe close to the metering tank and the height position B of the top end of the pipe close to the mixing tank is 30 cm-1000 cm.

5. The oxide catalyst production apparatus according to claim 1 or 2,

the pipe is connected to a lower portion of the measuring tank so as to be substantially parallel to the direction of gravity, and is bent on the way toward the mixing tank so as to be connected to a side wall portion of the mixing tank.