JP2019182795A - Floating layer reaction device, and manufacturing method of acrylonitrile - Google Patents

Abstract

To provide a floating layer reaction device and a manufacturing method of acrylonitrile, capable of alleviating thermal effects of abnormal heat generation at a lower part of a floating layer reactor for manufacturing acrylonitrile on the floating layer reaction device, and as a result, capable of manufacturing acrylonitrile stably and safely.SOLUTION: There is provided a floating layer reaction device having a floating layer reactor containing a catalyst layer, and a raw material gas supplier for supplying a raw material gas into the floating layer reactor, and used for manufacturing acrylonitrile, and further having a heat insulation material arranged in vicinity of the floating layer reactor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fluidized bed reactor and a method for producing acrylonitrile.

  Since the fluidized bed technology was developed in the latter half of the 19th century, it has been applied to various manufacturing technologies. Main industrial applications of fluidized beds include coal gasification furnaces, FCC plants, acrylonitrile production plants by propylene ammoxidation, polyethylene gas phase polymerization plants, maleic anhydride production plants, and the like. The fluidized bed reactor is characterized in that the reaction heat can be easily removed or added, so that the inside of the bed can be maintained at a uniform temperature, and the productivity is high. For this reason, fluidized bed reactors are expected to be applied and improved in various fields.

  The internal structure of a general fluidized bed reactor is described in Non-Patent Document 1, for example. A schematic diagram of such a normal fluidized bed reactor is shown in FIG. In the fluidized bed reactor shown in FIG. 3, an oxygen-containing gas is introduced from the oxygen-containing gas introduction pipe 2 of the fluidized bed reactor 1, and the introduced oxygen-containing gas passes through the blowout holes of the oxygen-containing gas dispersion plate 3 to the catalyst layer 6. Introduce. On the other hand, the raw material gas is introduced from the raw material introduction pipe 4, and the introduced raw material gas is introduced into the catalyst layer 6 through the outlet pipe of the raw material dispersion pipe 5. Thereby, the catalyst is caused to flow between the oxygen-containing gas and the raw material in the catalyst layer 6.

  Part of the catalyst particles jumps out of the catalyst layer 6 so as to accompany the product gas exiting the catalyst layer 6. A part of it is discharged out of the fluidized bed reactor so as to accompany the product gas. Therefore, in the fluidized bed reactor 1, cyclones 8 a, 8 b, 8 c for preventing the catalyst particles from being discharged to the outside are disposed on the upper part of the fluidized bed reactor 1. The product gas and the catalyst particles accompanying the product gas are introduced into the cyclone from the cyclone inlet 7. Such a cyclone is usually used in a form in which three stages of cyclones are connected in series in order to increase the collection efficiency of the catalyst particles. The three-stage cyclones are referred to as “No. 1 cyclone”, “No. 2 cyclone”, and “No. 3 cyclone”, respectively, in accordance with the order in which the product gas flows in the cyclone. The fluidized bed reactor of FIG. 3 has one series of three-stage cyclones, but the fluidized bed reactor may have two or more series of three-stage cyclones depending on the amount of product gas. The product gas is discharged to the outside of the fluidized bed reactor 1 through the product gas outflow pipe 10, and the catalyst particles are returned to the catalyst layer 6 through the diplegs 9a, 9b, 9c.

Patent Document 1 describes an apparatus for producing an α, β-unsaturated nitrile having an air and propylene nozzle pitch of 90 mm to 250 mm and a nozzle density of 16 nozzles / m ^{2 to} 120 nozzles / m ^2. Yes.

JP-A-3-123767

Kenji Hashimoto, Industrial Reaction Equipment, Baifukan, (1984), page 170

  The oxygen-containing gas dispersion plate installed in the fluidized bed reactor described in Non-Patent Document 1 is used from the viewpoint of achieving uniform dispersion of the oxygen-containing gas and good catalyst flow. Also in a fluidized bed reactor for producing acrylonitrile, an oxygen-containing gas dispersion plate is installed from the same viewpoint. Regarding such a fluidized bed reactor for producing acrylonitrile, the present inventor has found that a local high temperature part may develop at the bottom of the fluidized bed reactor as the operation progresses or when the operation is restarted after an emergency stop. It was.

  In the structure of the oxygen-containing gas dispersion plate and the raw material gas dispersion pipe described in Patent Document 1, in order to maintain the yield of the target product at a high level, good gas dispersion and catalyst flow can be achieved. It is not possible to cope with the thermal effect that the development of has on the fluidized bed reactor.

  Therefore, the problem to be solved by the present invention is that it is possible to alleviate the thermal influence on the fluidized bed reactor due to abnormal heat generation in the lower part of the fluidized bed reactor for producing acrylonitrile. Another object of the present invention is to provide a fluidized bed reactor capable of producing acrylonitrile safely and a method for producing acrylonitrile.

  The present inventor estimated that the cause of abnormal heat generation in the lower part of the conventional fluidized bed reactor is the accumulation of the catalyst and the like in the lower part of the fluidized bed reactor and the retention of gas. And as a result of further intensive studies, the present inventor found that the above problems can be solved by arranging a heat insulating material in the vicinity of the raw material gas supply device for supplying the raw material gas, and the present invention has been completed. .

That is, the present invention is as follows.
(1)
A fluidized bed reactor comprising a fluidized bed reactor including a catalyst layer and a source gas supplier for supplying a source gas into the fluidized bed reactor, and used for producing acrylonitrile,
A fluidized bed reaction apparatus further comprising a heat insulating material disposed in the vicinity of the raw material gas supplier.
(2)
The fluidized bed reactor is disposed below the catalyst layer, and a source gas dispersion pipe for dispersing the source gas supplied by the source gas supplier in the catalyst layer, and a predetermined distance from the source gas dispersion pipe And an oxygen-containing gas dispersion plate disposed below the source gas dispersion pipe and dispersing the oxygen-containing gas supplied into the fluidized bed reactor in the catalyst layer,
The fluidized bed reactor according to (1), wherein the location of the heat insulating material includes the following (A) and / or (B).
(A) On the oxygen-containing gas dispersion plate (B) The inner wall (3) of the fluidized bed reactor between the oxygen gas-containing gas dispersion plate and a height position 1 m away from the source gas dispersion pipe )
The oxygen-containing gas dispersion plate has a plurality of holes so that the oxygen-containing gas is uniformly dispersed in the catalyst layer;
The fluidized bed reactor according to (1) or (2), wherein the heat insulating material is disposed so as not to cover the plurality of holes.
(4)
The fluidized bed reactor according to any one of (1) to (3), wherein the heat insulating material is disposed on an inner wall surface of a side wall of the fluidized bed reactor.
(5)
Supplying a feed gas containing propylene and / or propane and ammonia and an oxygen-containing gas to a fluidized bed reactor containing a catalyst bed (1);
A step (2) of obtaining acrylonitrile by passing the source gas through the catalyst layer;
Including
The fluidized bed reactor is a method for producing acrylonitrile, in which a heat insulating material is disposed in the vicinity of a portion where the source gas is supplied.
(6)
The method for producing acrylonitrile according to (5), further comprising a step (3) of using the heat insulating material to alleviate the influence of abnormal heat generation in the vicinity of the portion where the source gas is supplied.

  According to the present invention, it is possible to mitigate the thermal influence due to abnormal heat generation in the lower part of the fluidized bed reactor for producing acrylonitrile. As a result, the fluidized bed reactor capable of producing acrylonitrile stably and safely, and the acrylonitrile A manufacturing method can be provided.

FIG. 1 is a schematic sectional view showing an example of a fluidized bed reactor according to the present invention. FIG. 2 is an enlarged view of the lower part of the fluidized bed reactor of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a general fluidized bed reactor. FIG. 4 is an enlarged view of a lower part of a general fluidized bed reactor.

  Hereinafter, a form for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with various modifications within the scope of the gist. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  The fluidized bed reactor according to the present embodiment includes a fluidized bed reactor including a catalyst bed, and a source gas supplier that supplies a source gas into the fluidized bed reactor, and is used for producing acrylonitrile. It is a reactor. The fluidized bed reaction apparatus further includes a heat insulating material disposed in the vicinity of the source gas supply device (for example, the outlet of the source gas supply device into the fluidized bed reactor). When the fluidized bed reactor is provided with a heat insulating material, the fluidized bed reactor can alleviate the thermal influence due to abnormal heat generation in the lower part of the fluidized bed reactor, and as a result, acrylonitrile can be produced stably and safely.

[Fluidized bed reactor]
FIG. 1 is a schematic cross-sectional view showing an example of a fluidized bed reactor according to the present embodiment. The fluidized bed reaction apparatus shown in FIG. 1 includes a fluidized bed reactor 1 and a raw material gas supplier 4 that supplies a raw material gas into the fluidized bed reactor 1. A fluidized bed reactor 1 shown in FIG. 1 corresponds to a main part of a gas phase reactor that separates a reaction system of a gas phase reaction from the outside. The shape of the fluidized bed reactor 1 is not particularly limited, and may be a known shape. The source gas supply device 4 is not particularly limited as long as the source gas can be supplied into the fluidized bed reactor 1. The shape of the raw material gas supply device 4 is not particularly limited, and may be, for example, a tubular shape. Examples of the raw material gas include a raw material gas usually used for producing acrylonitrile, and more specifically, propylene and / or propane, and ammonia.

(Fluidized bed reactor 1)
The fluidized bed reactor 1 includes, for example, a catalyst layer 6 formed in the lower part of the inside thereof, and is disposed below the catalyst layer 6, and the source gas supplied by the source gas supplier 4 is dispersed in the catalyst layer 6. The raw material gas dispersion pipe 5, the oxygen-containing gas introduction pipe 2 that is disposed at the bottom of the fluidized bed reactor 1 and introduces the oxygen-containing gas into the fluidized bed reactor 1, and the raw material gas dispersion pipe 5 have a predetermined distance. The oxygen-containing gas dispersion plate 3 is disposed below the source gas dispersion pipe and disperses the oxygen-containing gas supplied into the fluidized bed reactor 1 through the oxygen gas introduction pipe 2 into the catalyst layer 6, and Three stages of cyclones 8a, 8b, and 8c disposed above the inside of the bed reactor 1, a cyclone inlet 7 corresponding to the inlet of the cyclone 8a, and three stages connected to each of the cyclones 8a, 8b, and 8c Diplegs 9a, 9b and 9c and fluidized bed Heat insulation provided by construction between the product gas outflow pipe 10, the cooling coil 11, the air (oxygen-containing gas) dispersion plate 3, and the raw material gas dispersion pipe 5 disposed at the top of the reactor 1. The material 12 is provided.

(Catalyst layer 6)
The catalyst layer 6 is formed in the lower part inside the fluidized bed reactor 1. The catalyst layer 6 is filled with a fluidized bed catalyst corresponding to the type of reaction. The fluidized bed catalyst is not particularly limited, and examples thereof include a metal oxide catalyst supported on silica or the like. When the reaction is an ammoxidation reaction of propylene and / or propane, the fluidized bed catalyst includes Mo-V- (Sb and / or Ti), Mo-V-Fe, and Mo-Bi-Fe. An oxide is mentioned, and those having a particle diameter of 90 to 90% by mass of 10 to 197 μm and a crushing strength of 10 MPa or more are preferably used.

(Raw material gas dispersion pipe 5)
The raw material gas dispersion pipe 5 is disposed below the catalyst layer 6 and disperses the raw material gas supplied by the raw material gas supplier 4 in the catalyst layer 6. The source gas dispersion pipe 5 is not particularly limited as long as the source gas can be dispersed in the catalyst layer 6 and has a tubular form.

(Oxygen-containing gas introduction pipe 2)
The oxygen-containing gas introduction pipe 2 is disposed at the bottom of the fluidized bed reactor 1 and introduces an oxygen-containing gas into the fluidized bed reactor 1. The oxygen-containing gas introduction pipe 2 is not particularly limited as long as the oxygen-containing gas can be introduced into the fluidized bed reactor 1 and has a tubular form. Examples of the oxygen-containing gas include oxygen and air.

(Oxygen-containing gas dispersion plate 3)
The oxygen-containing gas dispersion plate 3 is disposed below the source gas dispersion pipe 5 at a predetermined distance from the source gas dispersion pipe 5, and the oxygen-containing gas supplied into the fluidized bed reactor 1 by the oxygen gas introduction pipe 2. The gas is dispersed in the catalyst layer 6. The oxygen-containing gas dispersion plate 3 is not particularly limited as long as the oxygen-containing gas can be dispersed in the catalyst layer 6 and has a plate-like form. A specific example of the oxygen-containing gas dispersion plate 3 is shown in FIG. FIG. 2 is a partial schematic view showing an example of the vicinity of the oxygen-containing gas dispersion plate 3 and the raw material gas dispersion pipe 5 of FIG. The oxygen-containing gas dispersion plate 3 shown in FIG. 2 has a plurality of holes so that the oxygen-containing gas is uniformly dispersed in the catalyst layer. The plurality of holes shown in FIG. 2 are evenly arranged with a predetermined interval. However, in the present embodiment, the arrangement form of the plurality of holes is not limited to this.

(Cyclone 8a-8c)
The cyclones 8 a to 8 c are disposed above the fluidized bed reactor 1. Although the fluidized bed reactor 1 shown in FIG. 1 has one series of cyclones, the number of cyclone series in the fluidized bed reactor of the present embodiment may be one or plural.

(Dipleg 9a-9c)
Each dipleg 9a-9c is connected to each cyclone 8a-8c. The fluidized bed reactor 1 shown in FIG. 1 has one series of diplegs, but the number of dipleg series in the fluidized bed reactor of the present embodiment may be one or plural.

(Production gas outflow pipe 10)
The product gas outflow pipe 10 is disposed at the top of the fluidized bed reactor 1 and flows out the product gas to the outside. The product gas outflow pipe 10 is not particularly limited as long as the product gas can flow out to the outside and has a tubular form.

(Cooling coil 11)
The cooling coil 11 is not particularly limited as long as it has a coiled form and can control the temperature in the fluidized bed reactor. In this example, the cooling coil includes a plurality of heat removal tubes and the like. When the gas phase reaction is an exothermic reaction, the reaction heat is removed using the cooling coil 11 provided in the fluidized bed reactor 1 to control the reaction temperature. The reaction temperature is measured by a reaction temperature measuring thermometer for measuring the reaction temperature, but it may be one usually used in a chemical plant, and the form is not particularly limited. In the fluidized bed reactor, it is preferable to install a plurality of reaction temperature measuring thermometers at locations where the temperature distribution of the catalyst bed can be grasped.

(Insulation material 12)
The heat insulating material 12 is disposed between the oxygen-containing gas dispersion plate 3 and the source gas dispersion pipe 5 by construction. As shown in FIGS. 1 and 2, the heat insulating material 12 is constructed so as not to cover a plurality of holes in the cross-sectional views. Accordingly, the fluidized bed reactor can alleviate the thermal influence on the fluidized bed reactor when abnormal heat is generated between the oxygen gas dispersion plate 3 and the raw material gas dispersion pipe 5, and the oxygen-containing gas and Dispersion of the source gas into the catalyst layer 6 is not hindered. The heat insulating material 12 may be disposed on the oxygen-containing gas dispersion plate 3 as shown in FIG. 2, or on the oxygen-containing gas dispersion plate 3 as shown in FIG. The gas dispersion plate 3 and the raw material gas dispersion pipe 5 may be disposed on the inner wall surface of the fluidized bed reactor 1. Thereby, the thermal influence at the time of abnormal heat_generation | fever in the bottom face and side wall of the fluidized bed reactor 1 can be relieved. In FIG. 2, the surface of the heat insulating material 12 is covered (covered) with the metal 13. However, the metal 13 is covered for the purpose of preventing the heat insulating material 12 from being worn by the fluidized bed catalyst. The cover is preferably installed on the heat insulating material 12.

  The heat insulating material 12 shown in FIG. 1 and FIG. 2 is disposed by construction between the oxygen-containing gas dispersion plate 3 and the raw material gas dispersion pipe 5, but in the fluidized bed reactor of this embodiment, the heat insulating material Is not particularly limited as long as it is disposed in the vicinity of the raw material gas supplier. The term “in the vicinity of the raw material gas supplier” as used herein refers to, for example, a portion where the thermal influence due to abnormal heat generation in the lower part of the fluidized bed reactor can be appropriately mitigated, and from the viewpoint of improving stability and safety (A It is installed on the inner wall of the fluidized bed reactor on the oxygen-containing gas dispersion plate and / or (B) on the inner wall of the fluidized bed reactor up to a height of 1 m away from the source gas dispersion pipe. It is preferable. From the same point of view, “near the source gas supply device” is 0.5 m upward from the source gas dispersion pipe from (A) the oxygen-containing gas dispersion plate and / or (B) the oxygen-containing gas dispersion plate. More preferably, it is disposed by construction on the inner wall of the fluidized bed reactor up to a distant position, and (A) on the oxygen-containing gas dispersion plate and / or (B) the oxygen-containing gas dispersion plate and the raw material gas. More preferably, it is arranged by construction on the reactor wall between the dispersion pipe. In addition, it is particularly preferable that the heat insulating material is applied at a location on a metal surface on which Mo pieces (molybdenum pieces) are deposited and there is a concern that the catalyst flow may be hindered.

  As the heat insulating material 12, a fire-resistant cement-like thing is preferable from a viewpoint of heat insulation and the ease of construction. A fire-resistant castable is more preferable, the main components are alumina and silicon dioxide, and the maximum use temperature is preferably 1500 ° C. or higher.

[Method for producing acrylonitrile]
The method for producing acrylonitrile of the present embodiment includes a step (1) of supplying a raw material gas containing propylene and / or propane and ammonia and air or oxygen to a fluidized bed reactor including a catalyst layer, and a raw material gas. And a step (2) of obtaining acrylonitrile by passing it through the catalyst layer, and in the fluidized bed reactor, a heat insulating material is disposed by construction in the vicinity of the portion for supplying the raw material gas.

  Hereinafter, the acrylonitrile production | generation method of this embodiment is demonstrated taking the case where the fluidized bed reaction apparatus shown in FIG. 1 is used as an example.

[Step (1)]
Step (1) is a step of supplying a raw material gas containing propylene and / or propane and ammonia and an oxygen-containing gas to a fluidized bed reactor containing a catalyst layer. The source gas is supplied to the fluidized bed reactor 1 by, for example, the source gas supply unit 4. The oxygen-containing gas is supplied to the fluidized bed reactor 1 through, for example, an oxygen-containing gas introduction pipe 2. From the viewpoint of safety, the oxygen-containing gas is not mixed with the raw material gas in advance in the pipe, but reacts from the oxygen-containing gas dispersion plate 3 provided at the lower portion of the fluidized bed reactor 1 through the oxygen-containing gas introduction pipe 2. Introduced into the vessel.

  The supplied raw material gas is filled with a necessary amount of the fluidized bed catalyst through the raw material gas supply device 4 connected to the lower side of the fluidized bed reactor 1 and the raw material gas dispersion pipe 5 connected to the raw material gas supply device 4. In the fluidized bed reactor. A fluidized bed reactor in which an oxygen-containing gas is filled with a required amount of a fluidized bed catalyst through an oxygen-containing gas introduction pipe 2 and an oxygen-containing gas dispersion plate 3 connected to the bottom (lower side) of the fluidized bed reactor 1. Introduced in. The reaction raw materials and reaction products generally flow through the reactor from bottom to top.

  The fluidized bed catalyst is fluidized by introducing the raw material gas into the catalyst layer. FIG. 1 shows the interface of the fluidized catalyst layer 6. The interface is stationary when the raw material gas is not introduced. After the introduction of the raw material gas, since the interface protrudes due to an increase in the porosity of the catalyst layer and large and small air bubbles, the layer height is not uniform. Therefore, the position of the interface is merely shown in an approximate and average manner.

[Step (2)]
Step (2) is a step of obtaining acrylonitrile by passing the raw material gas through the catalyst layer. The raw material gas reacts while passing through the catalyst layer to obtain a product gas containing acrylonitrile, acetonitrile, hydrogen cyanide and the like.

[Process (3)]
The method for producing acrylonitrile in the present embodiment uses the heat insulating material 12 to mitigate the influence (for example, thermal damage) due to abnormal heat generation in the vicinity of the portion for supplying the raw material gas (for example, in the vicinity of the raw material supplier) (or It is preferable to further include a step (3) of (suppressing). The relaxation step (3) may be performed before the step (2) or after the step (2).

  The method for producing acrylonitrile in the present embodiment includes a step (4) of discharging the product gas from the catalyst bed and introducing it into the cyclone, and then discharging the product gas from the fluidized bed reactor, and / or introducing the product gas into the cyclone. A step (5) of recovering the catalyst entrained during the process and returning it to the catalyst layer may be further included.

[Step (4)]
Step (4) is a step of discharging the product gas from the fluidized bed reactor 1 after discharging the product gas from the catalyst layer and introducing it into the cyclone. For example, the product gas obtained in the step (2) is discharged from the catalyst layer, introduced into the cyclones 8a, 8b and 8c from the cyclone inlet 7, and then discharged from the fluidized bed reactor 1.

[Step (5)]
Step (5) is a step of recovering the catalyst entrained when the product gas is introduced into the cyclone and returning it to the catalyst layer. When the product gas is discharged from the catalyst layer, the catalyst is scattered because the catalyst is entrained in the product gas. For example, a first-stage cyclone 8a, a second-stage cyclone 8b, and a third-stage cyclone 8c as shown in FIG. 1 are used in order to collect and separate the catalyst scattered with the generated gas. . The product gas accompanying the catalyst flows into the cyclone inlet 7 of FIG. 1 and passes through the first-stage cyclone 8a, the second-stage cyclone 8b, and the third-stage cyclone 8c in this order, and the produced gas and the catalyst are separated. . The separated catalyst is recovered in the first stage dipleg 9a, the second stage dipleg 9b, and the third stage dipleg 9c attached to each cyclone and returned to the catalyst layer 6.

  In the fluidized bed reactor, the distance between the air (oxygen) dispersion plate 3 and the raw material dispersion pipe 5 is usually 50 to 450 mm, and the raw material gas or air (oxygen) is fed into the fluidized bed catalyst in the same space. There are a number of nozzles that erupt inside. In addition, there are a support for the raw material dispersion pipe, a thermometer, various nozzles, and the like. During the acrylonitrile production, molybdenum (Mo) contained in the fluidized bed catalyst in the fluidized bed reactor is partially sublimated from the fluidized bed catalyst and exits into the reaction gas. Most of the sublimated Mo compound is vapor-deposited as Mo oxide on the surfaces of low temperature parts such as cooling coils, reactor walls, nozzles, and cyclones. These Mo oxides solidify on the surface by entraining a fluidized bed catalyst. The inventor has found that as the operation proceeds, the Mo oxide layer increases and surprisingly the thickness can reach 5-20 mm. The Mo oxide layer is peeled off due to heat shock or the like due to switching of the cooling coil during operation, temperature history during normal stop, emergency stop, etc., and falls to the lower part of the reactor. The Mo oxide is crushed by dropping to form a plate-like Mo piece having a surface area of several square centimeters to several tens of square centimeters. Most of the Mo pieces flow together with the fluidized bed catalyst and are repeatedly subdivided into small pieces having a size of several mm to micron order. On the other hand, a large Mo piece having a mass that does not flow, an outer peripheral part of the lower part of the reactor, or a device that hinders the flow, such as a Mo piece that has dropped in a place with poor fluidity such as the vicinity of a thermometer, nozzle, support, etc. In some cases, Mo pieces are deposited without being subdivided. Since this deposited Mo piece inhibits good catalyst flow, the catalyst at the site becomes a defective catalyst or is likely to cause abnormal heat generation. In order to solve the above-described problems, the present inventor has found that it is effective to provide an apparatus that copes with abnormal heat generation in the vicinity of a portion that supplies a source gas.

  Next, this embodiment will be described in more detail with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless departing from the gist thereof.

  The fluidized bed reactor used in the examples is the same as the fluidized bed reactor shown in FIG. The measuring instrument and attached equipment were normally used and were within the normal error range.

The yield and unreacted rate of the reaction product were calculated from the analytical data obtained by sampling the product gas and measured by gas chromatography (GC) according to the following equation.
(Yield (%) of reaction product) = (carbon mass in product (g)) / (carbon mass in organic compound (g) as reaction raw material supplied) × 100
(Unreacted rate (%)) = (Carbon mass (g) in organic compound as unreacted reaction raw material) / (Carbon mass (g) in organic compound as supplied reaction raw material) × 100
The GC measuring equipment and measurement conditions were as follows.
Gas chromatography: Shimadzu GC-14B
Column: Porapack-QS (50-80 Mesh)
Detector: FID
Carrier gas: Nitrogen

[Example 1]
Propylene, ammonia, and air, which are raw material gases for the reaction, were supplied to the fluidized bed reactor 1 shown in FIG. 1, and an ammoxidation reaction of propylene was performed as follows.

The fluidized bed reactor 1 was a vertical cylindrical type having an inner diameter of 8 m and a length of 20 m, and had an oxygen-containing gas dispersion plate 3 at a position 2 m from the bottom and a raw material gas dispersion pipe 5 thereon. 20 thermometers for measuring the temperature of the catalyst layer were attached between 1.5 to 4.5 m above the oxygen-containing gas dispersion plate 3. Two thermometers for measuring the reactor upper temperature were attached to the space above the cyclones 8a to 8c. On the oxygen-containing gas dispersion plate 3, a heat insulating material 12 was installed as shown in FIG. The heat insulating material 12 has a maximum operating temperature of 1800 ° C., 96% of Al ₂ O ₃ as main chemical components, 0.5% of SiO ₂ , a bulk specific gravity of 2.7-2.8, and a thermal conductivity of 400 ° C. A refractory castable of 13 kcal / mh ° C. and 1.27 kcal / mh ° C. at 800 ° C. was used. The catalyst has a particle size of 10 to 100 μm, an average particle size of 55 μm, a particle size of 24 wt. % Molybdenum-bismuth-iron-based supported catalyst and packed so as to have a stationary layer height of 2.7 m. The air from the oxygen-containing gas dispersing plate 3 and 56000Nm ³ / h feed, a 6200Nm ³ / h and ammonia propylene from raw material gas supply unit 4 was 6600Nm ³ / h feed. The reaction temperature was 440 ° C., the pressure at the top of the reactor was 0.70 kg / cm ² G, and the pressure at the bottom of the fluidized bed reactor 1 (near the raw material gas dispersion pipe 5) was 0.73 kg / cm ² G.

  When the reactor was started and stabilized, the reaction results were analyzed. As a result, the yield of acrylonitrile was 81.5%, and the unreacted rate of propylene was 1.1%. During the operation period of one year and one month after the start, the yield of acrylonitrile varied between 80.9-81.7% and the unreacted ratio of propylene varied between 0.80-1.3%. Thereafter, the reactor was stopped for 2 weeks for production adjustment. The catalyst in the reactor was held as it was for a two week shutdown period. Source gas and air were introduced into the reactor for resumption. After stabilization and analysis of the reaction results, the yield of acrylonitrile was 81.4%, and the unreacted ratio of propylene was 1.0%. The yield of acrylonitrile on the next day after the restart was 79.9%, and the unreacted ratio of propylene was 2.3%. The reactor was stopped in the evening of the same day because of the decrease in acrylonitrile yield and the high unreacted propylene rate. When the inside of the reactor was inspected, a catalyst lump (about 10 cm square) was found between the first nozzle and the second nozzle from the left in FIG. The nearby nozzle was melted, but the heat insulating material 12 and the oxygen-containing gas dispersion plate 3 were sound. The catalyst performance was sampled by sampling the catalyst lump in the previous period, but was deactivated. The other catalysts had no performance problems and could be reused.

[Example 2]
Using the same apparatus as in Example 1, propylene was changed to propane in the raw material gas, and the raw material gas was supplied to the fluidized bed reactor, and propane ammoxidation reaction was performed as follows.

The catalyst has a content of 1.3 wt.% With a particle size of 10-100 μm, an average particle size of 55 μm, and a particle size of 24 μm or less. % Molybdenum-vanadium-based supported catalyst and packed so as to have a stationary layer height of 2.2 m. Oxygen air from gas distribution plate 3 and 64500Nm ³ / h feed, a 4300Nm ³ / h and ammonia propane from feed gas dispersion tube was 4300Nm ³ / h feed. The reaction temperature was 440 ° C., the pressure in the upper part of the fluidized bed reactor 1 was 0.75 kg / cm ² G, and the pressure in the lower part of the fluidized bed reactor 1 (near the raw material gas dispersion pipe 5) was 0.77 kg / cm ² G. .

  When the reaction results were analyzed immediately after the start of the reactor operation, the yield of acrylonitrile was 52.1%, and the unreacted rate of propane was 10.8%. During the two-year operation period, the acrylonitrile yield varied from 51.7 to 52.5% and the unreacted propane rate varied from 9.9 to 11.3%. After 2 years, the reactor was shut down and the reactor was shut down. When the inside of the fluidized bed reactor 1 was inspected, Mo pieces were deposited near the leftmost nozzle in FIG. 2, and the cover of the heat insulating material 12 was melted. There was no abnormality in the catalyst and the oxygen-containing gas dispersion plate.

[Comparative Example 1]
The fluidized bed reactor was operated with the same catalyst as in Example 1 and the same flow rate of propylene, ammonia and air as in Example 1 except that the heat insulating material 12 was not applied.

  When the reaction results were analyzed immediately after the start of the reactor operation, the yield of acrylonitrile was 81.5%, and the unreacted rate of propylene was 1.1%. During the one-year operation period, the yield of acrylonitrile varied from 79.9 to 81.7%, and the unreacted rate of propylene varied from 0.75 to 2.0%. One year after the start of the reaction, the reactor was stopped. When the inside inspection of the reactor was conducted, there was a catalyst lump near the outer periphery, and the three raw material gas dispersion pipe nozzles and the oxygen-containing gas dispersion plate located near the catalyst lump were melted. Due to the repair of the oxygen-containing gas dispersion plate, the outage period was extended by 3 weeks.

  The present invention can be effectively used when performing a gas phase reaction using a fluidized bed reactor.

DESCRIPTION OF SYMBOLS 1 Fluidized bed reactor 2 Oxygen containing gas introduction pipe 3 Oxygen containing gas dispersion plate 4 Raw material gas introduction pipe 5 Raw material gas dispersion pipe 6 Catalyst layer 7 Cyclone inlet 8c First stage cyclone 8b Second stage cyclone 8a Third stage cyclone 9c First 1st stage prepreg 9b 2nd stage dipleg 9a 3rd stage dipleg 10 Product gas outflow pipe 11 Cooling coil 12 Heat insulating material 13 Metal

Claims (6)

A fluidized bed reactor comprising a fluidized bed reactor including a catalyst layer and a source gas supplier for supplying a source gas into the fluidized bed reactor, and used for producing acrylonitrile,
A fluidized bed reaction apparatus further comprising a heat insulating material disposed in the vicinity of the raw material gas supplier. The fluidized bed reactor is disposed below the catalyst layer, and a source gas dispersion pipe for dispersing the source gas supplied by the source gas supplier in the catalyst layer, and a predetermined distance from the source gas dispersion pipe And an oxygen-containing gas dispersion plate disposed below the source gas dispersion pipe and dispersing the oxygen-containing gas supplied into the fluidized bed reactor in the catalyst layer,
The fluidized bed reactor according to claim 1, wherein the place where the heat insulating material is disposed includes the following (A) and / or (B).
(A) On the oxygen-containing gas dispersion plate (B) Inner wall of the fluidized bed reactor between the oxygen gas-containing gas dispersion plate and a height position 1 m away from the source gas dispersion pipe The oxygen-containing gas dispersion plate has a plurality of holes so that the oxygen-containing gas is uniformly dispersed in the catalyst layer;
The fluidized bed reactor according to claim 1 or 2, wherein the heat insulating material is disposed so as not to cover the plurality of holes.   The fluidized bed reactor according to any one of claims 1 to 3, wherein the heat insulating material is disposed on an inner wall surface of a side wall of the fluidized bed reactor. Supplying a feed gas containing propylene and / or propane and ammonia and an oxygen-containing gas to a fluidized bed reactor containing a catalyst bed (1);
A step (2) of obtaining acrylonitrile by passing the source gas through the catalyst layer;
Including
The fluidized bed reactor is a method for producing acrylonitrile, in which a heat insulating material is disposed in the vicinity of a portion where the source gas is supplied.   The manufacturing method of acrylonitrile of Claim 5 which further includes the process (3) of relieving the influence by the abnormal heat_generation | fever near the site | part which supplies the said source gas using the said heat insulating material.