CN115957702A

CN115957702A - Method for filling catalyst into fluidized bed reactor and method for producing nitrile compound

Info

Publication number: CN115957702A
Application number: CN202310061358.4A
Authority: CN
Inventors: 渡边博一
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2015-03-13
Filing date: 2016-03-08
Publication date: 2023-04-14
Also published as: CN107206362A; TWI619552B; TW201707781A; WO2016147950A1; KR20170093913A; JPWO2016147950A1; KR101950629B1; JP6131480B2

Abstract

The present invention relates to a method for filling a catalyst into a fluidized bed reactor and a method for producing a nitrile compound. The method for filling a catalyst into a fluidized bed reactor of the present invention comprises the following steps: setting the effective sectional area of the fluidized bed reactor to Bm ² ]Setting the temperature in the fluidized bed reactor to T DEG C]And the total flow rate of the gas introduced into the fluidized bed reactor is Fnm ³ /h]Reacting the fluidized bedThe pressure in the vessel at the top of the column was P [ kPa ]]And substituted into the following formula (1) to obtain the gas flow rate U [ m/s ] in the fluidized bed reactor]The filling of the fluidized bed reactor with catalyst is started and then the U is increased. U = (F/B × ((273 + T)/273)/((101 + P)/101))/3600 formula (1).

Description

Method for filling catalyst into fluidized bed reactor and method for producing nitrile compound

The present application is a divisional application of the Chinese patent application having the filing date of 2016, 3, 8, and the application number of 201680006749.4, entitled "method for filling catalyst into fluidized bed reactor and method for producing nitrile compound".

Technical Field

The present invention relates to a method for filling a fluidized bed catalyst into a fluidized bed reactor used for a gas phase oxidation reaction of hydrocarbons, and a method for producing a nitrile compound.

Prior Art

Various methods for producing nitrogen-containing compounds by a vapor phase oxidation reaction using a hydrocarbon, ammonia, and an oxygen-containing gas as raw materials are known. In particular, a method for producing unsaturated nitriles by a gas-phase fluidized bed reaction using a hydrocarbon, ammonia, and an oxygen-containing gas as raw materials is known as an ammoxidation reaction. Among them, the production of acrylonitrile by ammoxidation of propylene is widely practiced industrially.

In general, a catalyst for fluidized bed is used for the ammoxidation. In large-scale industrial-scale ammoxidation reactions, catalysts optimized in composition, production method, shape, particle size, density, activity, and the like have been developed so that the performance of the fluidized bed catalyst can be sufficiently exerted.

Various proposals have been made regarding the composition of the catalyst, the method of preparation, and the like. As for the physical properties of the catalyst for a fluidized bed, preferable physical properties such as particle density, shape, particle size and the like have been proposed, and particularly, as for the particle size distribution, it is known that the fluidized state of the catalyst becomes good by maintaining the proportion of fine particles having a particle size of 44 μm or less in a certain range (non-patent document 1), and thus the reaction performance also changes.

Further, as a method for filling a catalyst for a fluidized bed, there are known: a method of raising the temperature in an atmosphere substantially free of oxygen and/or a flammable gas (patent document 1, patent document 2); and a method of effectively utilizing a gas discharged from a process after the reactor (patent document 3).

In addition, in the fluidized bed reactor, the reaction proceeds in a state where the gas flow rate in the reactor is equal to or higher than the final velocity of the fluidized bed catalyst, and therefore, part of the fine powder of the fluidized bed catalyst is scattered from the fluidized bed reactor to the outside of the reactor along with the gas in the reaction tower. Therefore, the following reaction method is generally employed: while replenishing a large amount of catalyst containing fine powder during the reaction, the particle size distribution of the catalyst in the reactor is maintained in an ideal range, thereby maintaining a good catalyst flow state for a long period of time (patent document 4).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2001-55355

Patent document 2: pamphlet of International publication No. 2012/096367

Patent document 3: japanese laid-open patent publication No. 2002-53519

Patent document 4: japanese patent laid-open publication No. 63-36831

Non-patent document

Non-patent document 1: chemical engineering [10] p.1013-1019, vol.34 (1970)

Disclosure of Invention

Problems to be solved by the invention

In the production of a target product using a fluidized bed, not only optimization of a catalyst but also adoption of optimum operating conditions for fully utilizing the catalytic ability cannot achieve improvement of the final reaction result. In particular, in order to improve the reaction performance, selection of conditions for catalyst filling is an important factor.

The methods of patent documents 1 to 3 are all intended to reduce oxygen and combustible gas which adversely affect catalysts, devices and safety. Further, patent document 4 aims to: after the reaction was started, the flow state of the catalyst was maintained well. When filling a fluidized bed reactor with a catalyst, a gas for introduction into the reactor may be used, but patent documents 1 to 4 do not describe the flow rate of the gas. That is, no study has been made on optimizing the flow rate of the gas in the reactor when the catalyst is charged into the fluidized bed reactor in order to improve the reaction performance of the catalyst.

The inventors of the present invention have studied the flow rate of the gas in the reactor and found the following.

That is, the catalyst can be filled in a short time by increasing the flow rate of the gas in the reactor during catalyst filling. However, the amount of scattering of the catalyst (particularly, fine powder) increases, and the possibility of occurrence of device operation failure such as clogging of piping due to the scattered catalyst increases.

If the catalyst is packed and the reaction after the packing is carried out while the catalyst (particularly, the fine powder) is fluidized in a state of scattering a large amount, the fluidized state of the catalyst is deteriorated and the reaction becomes unstable, which causes industrial problems such as a decrease in the yield of the target product and deterioration of a part of the catalyst.

Further, by increasing the filling time of the catalyst by decreasing the flow rate of the gas, the amount of scattering of the catalyst can be suppressed. However, a long time is required until the completion of the filling of the catalyst, and the energy consumption of the combustible gas or the like used when the introduction gas introduced into the reactor is preheated is also excessive.

None of the methods described in patent documents 1 to 4 considers: when the fluidized bed reactor is charged with the catalyst, the flow rate of the gas in the reactor is optimized, and therefore, the reaction performance of the catalyst cannot be improved to a level that can meet the industrial demand.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress the amount of catalyst scattering to the outside of a reactor and to fill the reactor with the catalyst in a shorter time, thereby efficiently performing a reaction with a higher yield.

Means for solving the problems

The present inventors have made an effort to study a method for filling a catalyst for a fluidized bed in a fluidized bed reactor. As a result, they have found that the amount of catalyst scattering to the outside of the reactor can be suppressed by performing an operation of increasing the gas flow rate after the start of catalyst filling, and the reaction can be carried out with a high yield of the desired product without deteriorating the flow state of the catalyst, and have completed the present invention. Further, it has been found that the gas flow rate can be increased by filling a certain amount of catalyst into a dipleg serving as a catalyst introduction pipe of a cyclone (catalyst trap).

That is, in order to solve the above problems, a method for filling a catalyst into a fluidized bed reactor (hereinafter, referred to as "catalyst filling method of the present invention") of the present invention is characterized by comprising the steps of: setting the effective sectional area of the fluidized bed reactor as Bm ² ]Setting the temperature in the fluidized bed reactor to T DEG C]And the total flow rate of the gas introduced into the fluidized bed reactor is Fnm ³ /h]And setting the pressure at the top of the fluidized bed reactor to P [ kPa ]]And substituting the gas flow rate into the following formula (1), starting to fill the catalyst into the fluidized bed reactor at the obtained gas flow rate U in the fluidized bed reactor, and then increasing the U.

U = (F/B × ((273 + T)/273)/((101 + P)/101))/3600. Formula (1)

In the catalyst filling method of the present invention, the value of T is more preferably 100 to 500 ℃. Further, in the catalyst filling method of the present invention, it is more preferable that F is increased and U is increased.

In the catalyst filling method of the present invention, more preferably: the fluidized bed reactor is provided with a catalyst return unit which returns the catalyst recovered in the fluidized bed reactor to the inside of the fluidized bed reactor from a position vertically below the position where the catalyst is recovered, calculates the amount of the catalyst from a pressure difference of at least 2 locations different in position in the vertical direction in the catalyst return unit, and increases the amount of the catalyst when the amount of the catalyst reaches a predetermined value.

The catalyst-filling method of the present invention can be suitably used in the form of a catalyst for producing a nitrile compound as the catalyst.

The method for producing a nitrile compound of the present invention is characterized in that: comprising the step of carrying out the catalyst filling method of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the following effects are exhibited: by suppressing the amount of catalyst scattering to the outside of the reactor and filling the catalyst in a shorter time, the flow state of the catalyst can be favorably maintained, hot spots (hot spots) are not generated, energy consumption is reduced, and the reaction can be efficiently performed with a higher yield.

Drawings

Fig. 1 is a diagram showing a schematic configuration of an embodiment of a fluidized bed reactor used in the catalyst filling method of the present invention.

Detailed Description

(catalyst filling method)

The catalyst filling method of the present invention comprises the following steps: setting an effective sectional area of the fluidized bed reactor to Bm ² ]Setting the temperature in the fluidized bed reactor to T DEG C]And the total flow rate of the gas introduced into the fluidized bed reactor is Fnm ³ /h]And setting the pressure at the top of the fluidized bed reactor to P [ kPa ]]And substituted into the following formula (1), starting to fill the catalyst into the fluidized bed reactor at the obtained gas flow rate U in the fluidized bed reactor, and then increasing U.

U = (F/B × ((273 + T)/273)/((101 + P)/101))/3600. Formula (1)

In addition, the gas flow velocity U [ m/s ] in the fluidized bed reactor may be set as follows]Called "gas flow rate U", which defines the effective cross-sectional area B m of the fluidized bed reactor ² ]Called the effective sectional area B, and the temperature T in the fluidized bed reactor is lower than]Referred to as "temperature T", the gas introduced into the fluidized bed reactor is referred to as "introduction gas", and the total flow rate of the introduction gas is Fnm ³ /h]Referred to as "total flow rate of introduced gas F", the pressure P [ kPa ] at the top of the fluidized bed reactor]Referred to as "overhead pressure P".

For example, after the start of the catalyst filling, the gas flow rate U in the fluidized bed reactor is increased in the middle of the catalyst filling, whereby the scattering of the filled catalyst out of the fluidized bed reactor can be suppressed. As the particle diameter of the catalyst is smaller, the catalyst is more likely to scatter outside the fluidized bed reactor. If the catalyst scattered in the entire catalyst is biased toward a catalyst having a small particle diameter, the particle size distribution is changed from that before filling, and the flow state of the catalyst is deteriorated. However, according to the present invention, the deterioration of the flow state of the catalyst can be prevented, and thus the target product can be obtained in high yield by the reaction carried out thereafter. Further, since the filling can be completed in a short time, the catalyst can be efficiently filled into the fluidized bed reactor. Further, scattering of the catalyst having a small particle diameter can be prevented, and deterioration of the flow state of the catalyst can be prevented. Therefore, the flowing state of the catalyst is well maintained. Furthermore, since the fluid state is maintained well, the occurrence of temperature unevenness (hot spot) can be suppressed even in the continuous reaction for producing the target. Further, since the filling can be completed in a short time, the power consumption can be reduced.

The catalyst packing method of the present invention can be suitably applied to packing of a catalyst in synthesizing nitriles by an ammoxidation reaction of a hydrocarbon having 1 to 6 carbon atoms. Among them, the catalyst filling method of the present invention can be more suitably used as the following method: a method of packing a catalyst for use in the synthesis of acrylonitrile by the ammoxidation of propylene and/or propane and methacrylonitrile by the ammoxidation of isobutylene and/or isobutane.

(step of increasing the gas flow rate U m/s in the reactor)

The catalyst filling method of the present invention comprises: and (3) increasing the gas flow rate U represented by the formula (1).

The gas flow velocity in the fluidized bed reactor is a value obtained by dividing the flow rate of the introduced gas by the effective cross-sectional area and correcting the temperature and the pressure. The specific value range of U is preferably 0.07m/s or more, more preferably 0.10m/s or more, and further preferably 0.46m/s or less, more preferably 0.43m/s or less. If the flow rate is within the above range, the larger the gas flow rate in the reactor, the more the catalyst can be charged into the reactor in a short time, and the more the productivity of the reaction can be improved. In addition, if the flow rate is within the above range, the smaller the gas flow rate in the reactor, the more the scattering of the catalyst during the filling of the catalyst can be suppressed, and the more the temperature in the reactor can be suppressed from decreasing.

(effective cross-sectional area B [ m ] of fluidized bed reactor ² ])

The effective cross-sectional area B is an area obtained by subtracting a cross-sectional area of the content from a cross-sectional area when the fluidized bed reactor is cut in a horizontal direction. Specifically, the effective cross-sectional area is, for example, a cross-sectional area of a portion (reaction portion or dense layer) where a reaction between the raw material gas and the catalyst occurs above a position (height) where the raw material gas is introduced, and is a cross-sectional area obtained by subtracting a cross-sectional area of a content such as a dipleg.

The size of the fluidized bed reactor used in the catalyst-packing method of the present invention is not particularly limited, and if it is for industrial production, the effective cross-sectional area of the reactor is usually 10m ² ～200m ² The range of (1). When the amount is within the above range, the larger the effective cross-sectional area is, the more the productivity of the intended product can be improved. In addition, if the effective cross-sectional area is within the above range, the smaller the effective cross-sectional area, the better the operability of the device such as temperature control.

(temperature in fluidized bed reactor T [ ° C ]

The temperature T is determined by measuring the temperature in the fluidized bed reactor. The measurement site may be, for example, a portion (reaction portion or thick layer) that causes a reaction with the catalyst at a position (height) higher than a position at which the raw material gas is introduced, which will be described later. The temperature T is a temperature after a change if the temperature changes by performing the step of increasing the gas flow rate U. The formula (1) corrects the influence due to the change in temperature by: the flow rate (F/B) of the introduced gas per unit effective cross-sectional area, which is obtained by dividing the total flow rate F of the introduced gas by the effective cross-sectional area B, is multiplied by (273 + T)/273. The influence of a change in temperature is considered to mean, for example, a change in volume of gas and a change in flow rate due to a change in temperature. Thus, by varying the temperature T, the gas flow rate U can also be increased. For example, by increasing the temperature T, the gas flow rate U can be increased. In addition, "273" is an approximate value used to calculate a value of temperature in degrees centigrade (° c) in thermodynamic temperature (K).

In the method for filling a catalyst for a fluidized bed of the present invention, the temperature T in the fluidized bed reactor at the time of filling the catalyst is usually in the range of 100 to 500 ℃. If the temperature is within the above range, the reaction can be started more quickly after filling the catalyst with a higher temperature, and the flow state of the catalyst becomes better. In addition, if the temperature is within the above range, the lower the temperature is, the lower the fuel consumption per unit time used for heating the gas introduced into the fluidized bed reactor in the catalyst packing can be suppressed.

(pressure P [ kPa ] at the top of the fluidized bed reactor)

The top pressure P is determined by measuring the pressure at the top of the fluidized bed reactor. The column top pressure P is a column top pressure after a change in the temperature of the column by performing the step of increasing the gas flow rate U. Said formula (1) corrects the influence due to the change in pressure by dividing the flow rate of the introduced gas per unit effective sectional area (F/B) by (101 + P)/101. The influence of the change in pressure is considered to mean, for example, a change in volume of the gas and a change in flow rate due to a change in pressure. Thus, by varying the overhead pressure P, the gas flow rate U can also be increased. The gas flow rate U can be increased, for example, by reducing the overhead pressure P. In addition, "101" is an approximate value of a value used for calculating a value in pascal in terms of standard atmospheric pressure.

(Total flow rate of gas introduced into the fluidized bed reactor F [ Nm ] ³ /h])

Examples of the gas introduced into the fluidized bed reactor include: a fluidizing gas for fluidizing the catalyst packed in the fluidized bed reactor 10, and a catalyst transport gas for transporting the catalyst to the fluidized bed reactor. Since the flow rates of these gases are the flow rates set by the user, the total flow rate F of the introduced gases is obtained by summing the flow rates of the gases set by the user.

The types of the fluidizing gas and the catalyst-transporting gas are not particularly limited, and examples thereof include: pure oxygen, air, a mixed gas of pure oxygen and air, and the like. In addition, these gases may be diluted with other gases. The gas used for dilution is not particularly limited as long as it does not adversely affect the catalyst performance and the gas-phase oxidation reaction, and examples thereof include: air, nitrogen, helium, and the like. There are generally cases where air, oxygen, or an oxygen-containing gas diluted to an arbitrary concentration by an inert gas is used.

The total flow rate F of the introduced gas includes the flow rate of the gas, if any, introduced into the fluidized bed reactor, in addition to the fluidizing gas and the catalyst-transporting gas. Examples of such a gas include: purge gas for the raw material gas line or each differential pressure measurement line, and the like.

(preferred combination of temperature T, overhead pressure P and total flow rate F of introduced gas)

The values of the temperature T, the overhead pressure P, and the total flow rate F of the introduced gas are not particularly limited, since they vary depending on the size, structure, and the like of the fluidized bed reactor. The gas flow rate U is calculated by specifying the effective cross-sectional area B and then specifying a combination of 3 values of the temperature T, the column top pressure P, and the total flow rate F of the introduced gas.

(period for increasing gas flow rate U m/s in fluidized bed reactor)

The timing for increasing the gas flow rate U may be appropriately set according to the target filling time, the amount of scattering of the catalyst to be suppressed, and the like, and may be set as long as a part of the filled catalyst enters the fluidized bed reactor to start filling of the catalyst.

In addition, in order to improve the catalyst capturing efficiency, a plurality of cyclones are often connected and provided in the fluidized bed reactor. A dipleg is typically provided in the cyclone. The dipleg is a device for returning the catalyst recovered in the fluidized bed reactor to the fluidized bed reactor from a lower portion of the fluidized bed reactor (a position vertically below the position of recovery).

In general, the lowermost portion of the dipleg is opened in the reactor (or a reverse plate is provided) because of a large circulation amount of the catalyst or the like in the first stage of the dipleg, and a trickle valve (catalyst discharge amount adjusting means) or the like is provided at the lower end portion of the dipleg provided in the cyclones in the second and third stages.

In the catalyst filling method of the present invention, the period for which the gas flow rate U [ m/s ] in the fluidized bed reactor is increased is preferably set in accordance with the amount of the catalyst in the dipleg, and preferably in accordance with the amount of the catalyst in the dipleg of the first stage in the dipleg (the one in which the lowermost portion is open, or in which a reversing plate or the like, a trickle valve is provided). Further, it is also more preferable to increase the gas flow rate U in the fluidized bed reactor when the amount of the catalyst in the dipleg becomes a predetermined value. The above value is preferably 0.1 vol% or more, and more preferably 0.3 vol% or more, for example. In the absence of catalyst in the dipleg, the following are present: the gas and the catalyst introduced into the fluidized bed reactor enter from the open lower end of the dipleg (countercurrent flow), rise up to the cyclone part, and in this state, the catalyst scatters out of the system. If the lower end portion of the dipleg is sealed by the catalyst, the entry of the gas and the catalyst can be prevented. The minimum value of the amount of the catalyst in the dipleg of the first stage, the sealing of which can be confirmed by differential pressure, is preferably 0.1 vol% or more, more preferably 0.3 vol% or more. That is, after the lower end portion of the dipleg is confirmed to be sealed, the gas flow rate U is increased, whereby the scattering of the catalyst can be more efficiently suppressed, and the filling time can be shortened.

For example, the total flow rate F of the gas is set to be constant in advance, and the temperature and pressure that change with time are set to be constantly changing. In this state, it is only necessary to confirm that the lower end of the dipleg is covered with the catalyst, and increase the total flow rate F of the gas and increase the gas flow rate U. In addition, the total flow rate F of the gas may be adjusted in addition to the purpose of increasing the gas flow rate U. For example, adjustment for suppressing the influence of the flow characteristics of the catalyst, the flow characteristics of the flow meter device, or the like can be appropriately performed.

The method for measuring the amount of catalyst in the dipleg is not particularly limited, and may be calculated from the pressure difference between 2 locations having different heights (positions in the vertical direction), for example, the vicinity of the location connected to the cyclone and the vicinity of the catalyst return port at the lowermost portion in the dipleg.

(amount of increase in gas flow rate U [ m/s ] in the fluidized-bed reactor)

The amount of increase in the gas flow rate U can be set as appropriate according to the target filling time, the amount of scattering of the catalyst to be suppressed, and the like.

Even if the gas flow rate U in the fluidized bed reactor is slightly increased after the start of the filling, the catalyst can be filled while suppressing the scattering in the initial stage, and the filling can be completed in a shorter time after the gas flow rate U in the fluidized bed reactor is increased.

The specific numerical value of the amount of increase is, for example, preferably 2% or more, more preferably 4% or more, with respect to the value at the start of filling, from the viewpoint of expression of a clear effect due to an increase in the gas flow rate. From the viewpoint of suppressing catalyst scattering, the content is preferably 200% or less, and more preferably 150% or less.

(method of increasing the gas flow rate U m/s in a fluidized-bed reactor)

The method for increasing the gas flow rate U is not particularly limited, and it is more preferable to increase the total flow rate F of the introduced gas. The reason is that the gas flow rate U can be easily increased.

It should be noted, however, that the total flow rate F of the introduced gas must be increased until the gas flow rate U is increased. That is, there are also cases where: even if the operation of increasing the total flow rate F of the introduced gas is performed, the temperature T and the column top pressure P change due to the effect of the increase, and as a result, the gas flow rate U does not increase. However, in the catalyst filling method of the present invention, it is necessary to increase the gas flow rate U. Therefore, when the operation of increasing the total flow rate F of the introduced gas is performed, it is preferable to measure the temperature T and the column top pressure P and operate them in a direction in which the gas flow rate U increases as necessary. More preferably, the gas flow rate U is calculated from the above formula (1) and an increase is confirmed.

Furthermore, it should also be noted that: if the gas flow rate U is increased, it is not necessary to increase the total flow rate F of the introduced gas. It is the scope of the catalyst filling method of the present invention if the total flow rate F of the introduced gas is controlled in such a manner as to be intentionally concentrated within a certain range while the gas flow rate U is increased. For example, the total flow rate F of the gas is set to be constant, and the gas flow rate U is repeatedly increased and decreased within a certain range by flow rate fluctuation (hunting). Even if the total flow rate F of the gas is constant within the predetermined range, the catalyst can be filled while suppressing the scattering to a desired degree for a desired period of time. Such operations are also within the scope of the catalyst filling process of the present invention.

The operation for increasing the gas flow rate U may be performed once or more than twice. For example, the gas flow rate U can be increased to the target value of the increased gas flow rate U in one operation, or can be increased in stages by a plurality of times. The number of times may be appropriately set according to the flow state, filling time, and the like of the target catalyst.

Further, the gas flow rate U may be increased in a short time or may be slowly increased.

(fluidized bed reactor)

The fluidized bed reactor used in the catalyst-packing method of the present invention may be any one selected from conventionally known fluidized bed reactors used for fluidized bed reactions. Here, an embodiment of a fluidized bed reactor used in the catalyst filling method of the present invention will be described with reference to fig. 1. Fig. 1 is a schematic configuration diagram of a fluidized bed reactor 1 including a fluidized bed reactor 10.

In the present embodiment, the fluidized-bed reactor 1 is an apparatus for producing acrylonitrile by ammoxidation of hydrocarbons.

The fluidized-bed reactor 10 is a vertical cylindrical fluidized-bed reactor. The fluidized-bed reactor 10 is connected to a gas supply conduit 16. A cyclone 12 and a gas distribution plate 19 are provided in the fluidized bed reactor 10. Further, a gas supply port 20 is provided in the fluidized bed reactor 10. Further, a fluidized-bed reactor 10 is connected to the catalyst hopper 2. Further, a plurality of pressure measurement points (not shown) are provided in the fluidized bed reactor 10, and the total amount of the catalyst present in the fluidized bed reactor 10 can be calculated from the measured pressure difference.

(catalyst hopper 2)

The catalyst hopper 2 is used to store catalyst for filling into the fluidized bed reactor. The catalyst X is fed from the catalyst hopper 2 ₁ Gas X for catalyst transport ₂ And (5) carrying. Namely, catalyst X ₁ With the catalyst-transporting gas X ₂ The merged catalyst-containing gas X is supplied into the fluidized-bed reactor 10.

(catalyst)

The catalyst to which the catalyst filling method of the present invention is applied is not particularly limited, and the method can be suitably used for a catalyst used for an ammoxidation reaction and/or an oxidation reaction of a hydrocarbon having 1 to 6 carbon atoms, and the like. Examples of such catalysts include: metal oxide catalysts containing molybdenum and bismuth, metal oxide catalysts containing iron and antimony, metal oxide catalysts containing molybdenum and vanadium, metal oxide catalysts containing uranium and antimony, and the like. Among them, the catalyst is more suitably used for producing a nitrile compound.

The shape of the catalyst is not particularly limited, and a powdery catalyst is more preferable. Further, the particle diameter is preferably 5 μm or more, more preferably 10 μm or more, and preferably 200 μm or less, more preferably 180 μm or less.

(gas supply conduit 16)

The gas supply conduit 16 is a gas supply conduit for supplying the raw material gas Z to the fluidized bed reactor 10 when the reaction for producing the target product is performed after the catalyst is filled. The raw material gas Z includes gaseous hydrocarbon compounds, gaseous ammonia, and steam. The gas supply conduit 16 is provided below the fluidized bed reactor 10, and branches into a plurality of branch pipe portions 17. A nipple (raw material spreading nozzle) 18 that opens toward the bottom surface of the fluidized bed reactor 10 is connected to the tip of each branch pipe 17.

(raw gas Z)

Examples of the source gas Z include: examples of the hydrocarbon having 1 to 6 carbon atoms include butanes such as methane, ethane, ethylene, propane, propylene, n-butane and isobutane, butenes such as n-butene and isobutene, pentanes such as n-pentane and isopentane, pentenes such as n-pentene and isopentene, hexanes such as n-hexane and isohexane, and hexenes such as n-hexene and isohexene.

(cyclone 12)

The cyclone 12 serves to separate the gas from the catalyst. In the cyclone 12 are provided: an inlet 13 for introducing gas and catalyst into the cyclone 12, a gas outlet 15 for discharging separated gas to the outside of the fluidized bed reactor 10, and a dipleg 14 for returning the separated catalyst to the catalyst fluidized bed 11 in the reactor.

As shown in fig. 1, the fluidized bed reactor has a structure in which a plurality of series of 3 cyclones 12 are connected inside the reactor (of which only 1 series of 3 cyclones 12 connected is shown in fig. 1). As shown in fig. 1, the two cyclones 12 are connected by a gas outflow pipe 15, and the other gas outflow pipe 15 discharges the gas to the outside of the fluidized bed reactor 10.

(gas dispersion plate 19)

The gas distribution plate 19 is used to distribute the oxygen-containing gas Y supplied from the gas supply port 20 into the fluidized bed reactor 10. The gas distribution plate 19 is provided between the gas supply port 20 and the gas supply conduit 16.

(gas supply port 20)

The gas supply port 20 is used to supply the gas Y containing oxygen to the fluidized bed reactor 10. The gas supply port 20 is provided at the bottom of the fluidized bed reactor 10.

(gas containing oxygen Y)

The oxygen-containing gas Y is a fluidizing gas for flowing the catalyst in the fluidized-bed reactor 10 at the time of catalyst filling, and is a gas for supplying oxygen for reaction at the time of reaction.

The oxygen-containing gas Y as a flowing gas at the time of filling the catalyst and the oxygen-containing gas Y as a gas for supplying oxygen at the time of reaction may be the same gas or different gases. The specific type of the oxygen-containing gas Y is based on the description of the fluidizing gas.

(method for producing nitrile Compound)

The method for producing a nitrile compound of the present invention includes the step of performing the catalyst-filling method of the present invention. By adopting the catalyst filling method of the present invention, the flow state of the catalyst in the fluidized bed reactor is good, and a large amount of fine catalyst particles are present in the fluidized bed reactor without scattering. Therefore, a nitrile compound can be obtained in high yield.

After the catalyst filling method of the present invention is performed, the reaction for producing a nitrile compound may be started at any time of the user. For example, the reaction may be started after confirming that the flow state of the catalyst in the fluidized bed reactor is constant. When the reaction is started, the reaction temperature may rise due to heat generation, the pressure may fluctuate, and the flow state of the catalyst may change. When the state changes greatly and unstably before the reaction starts, it is preferable in terms of safety that the reaction starts after the state changes to a predetermined range and the state is stable. In addition, the temperature may be decreased before the reaction is started by predicting the temperature increase due to the reaction before the reaction to produce the nitrile compound.

The raw material gas supplied to the fluidized bed reactor may be diluted with an inert gas such as nitrogen or carbon dioxide, a saturated hydrocarbon, an alcohol, or the like, or may be used with an increased oxygen concentration.

In the method for producing a nitrile compound of the present invention, the composition ratio of the raw material gas for the vapor phase oxidation reaction is not particularly limited, and it is more preferable to set the molar ratio of at least one compound selected from the group consisting of the hydrocarbons having 1 to 6 carbon atoms to ammonia/oxygen in the range of 1/0.5 to 2.0/1.0 to 5.0 in order to improve the yield of the target product.

The reaction conditions for the gas phase oxidation to be applied in the method for producing a nitrile compound of the present invention are not particularly limited, and the reaction temperature is usually 350 to 500 ℃ and the reaction pressure is usually normal pressure to 500kPa.

In the present invention, the method for supplying at least one compound selected from the group consisting of the hydrocarbons having 1 to 6 carbon atoms, ammonia, and an oxygen-containing gas into the reactor is not particularly limited, and the following may be used: a sprinkler (distributor) system, a system of supplying through a dispersion plate, and the like.

Further, the at least one compound selected from the group consisting of hydrocarbons having 1 to 6 carbon atoms, ammonia, and a gas containing oxygen may be supplied separately to the fluidized bed reactor, or may be supplied by mixing all or a part thereof. In terms of safety and the like, the method is generally a method in which at least one compound selected from hydrocarbons having 1 to 6 carbon atoms, ammonia, and an oxygen-containing gas are separately supplied into a fluidized bed reactor.

In addition, from the viewpoint of efficiency, the production of a nitrile compound may be continued after the catalyst is filled, as described above.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the respective embodiments are also included in the technical scope of the present invention. The present invention will be described in detail below by way of examples and comparative examples, but the present invention is not limited to the following descriptions as long as the invention does not depart from the gist thereof.

Examples

Example 1

(filling of the fluidized bed into the reactor with the catalyst)

The fluidized bed catalyst (catalyst composition, fe) ₁₀ Sb ₂₀ Mo _0.5 W _0.4 Te _1.4 Cu ₃ Ni ₁ P _0.5 B _1.8 Cr _0.3 Mn _0. ₁ K _0.1 O _x (SiO ₂ ) ₆₀ (ii) a Here, x is the number of oxygen atoms necessary to satisfy the valence of each component except silica) 110 tons is 8.0m (the effective cross-sectional area B is 47 m) in the inner diameter from the catalyst hopper ² ) The vertical cylindrical fluidized bed reactor is filled.

As the fluidized bed reactor, a fluidized bed reactor equipped with the same, and a hopper for a catalyst, the apparatus and hopper shown in fig. 1 were used.

Air is used as a gas for fluidizing and a gas for transporting a catalyst to a fluidized bed reactor, and the total flow rate F of the gas is 12X 10 ³ Nm ³ H, the filling of the catalyst into the reactor was started under the conditions of an internal reactor temperature T of 420 ℃ and an internal reactor pressure P of 8 kPa. The gas flow rate U in the reactor at the start of filling (filling time: 0 hour) was 0.17m/s. The flow rate of the catalyst-transporting gas is only required to be a flow rate at which the catalyst can be transported, and in the examples and comparative examples, the flow rate of the fluidizing gas is extremely large compared to the flow rate of the catalyst-transporting gas, so the total flow rate F of the gas is set to be substantially the same as the flow rate of the fluidizing gas (the same applies to the following examples and comparative examples).

11.5 hours after the start of the catalyst filling, when the catalyst filling in the dipleg became 1.6 vol%, and when the filling amount of the catalyst into the fluidized bed reactor became 64 tons, the flow gas flowing into the fluidized bed reactor was increased to set the total flow rate F of the gas to 37 × 10 ³ Nm ³ /h。

After the flow-use gas had increased (11.7 hours), the temperature T in the reactor was 345 ℃, the overhead pressure P was 21kPa, and the gas flow rate U was 0.41m/s.

Finally the catalyst filling can be completed with a catalyst filling time of 12.9 hours. The catalyst loading was 110 tons, and it was confirmed that almost the entire amount of the catalyst was loaded in the reactor. The amount of catalyst charged after completion of catalyst charging was determined from the pressure difference measured at the bottom of the fluidized bed reactor and at the portion where the reaction proceeds at a position higher than the position at which the raw material gas is introduced.

Table 1 shows values from the start of filling to the completion of filling.

[ Table 1]

(ammoxidation reaction after filling the catalyst)

The ammoxidation reaction was carried out using a packed fluidized bed reactor in which the catalyst was completed. Using air as the oxygen source, the composition was propylene: ammonia: oxygen =1:1.1:2.3 (molar ratio) of the raw material gas is fed into the reaction column. The reaction pressure is set to 180 to 220kPa, the reaction temperature is set to 455 to 465 ℃, and the gas flow rate in the reactor is set to 50 to 70cm/sec.

In the reaction under the above conditions, the reaction temperature was detected by thermocouple thermometers provided at a plurality of locations, but temperature unevenness (hot spots) during the reaction was not observed, and the catalyst was in a good flow state. The average yield of acrylonitrile was 77.4%.

Example 2

(filling of the fluidized bed into the reactor with catalyst)

In the same manner as in example 1, the fluidized bed reactor shown in fig. 1 was charged with the fluidized bed catalyst. Air was used as a gas for fluidizing and a gas for transporting a catalyst to the fluidized bed reactor, and the total flow rate F of these gases was set to 23 × 10 ³ Nm ³ H is used as the reference value. The gas flow rate U in the reactor at the start of filling (filling time 0 hour) was 0.30m/s. The filling of the catalyst into the fluidized bed reactor was started under the conditions that the temperature T in the fluidized bed reactor was 420 ℃ and the overhead pressure P in the fluidized bed reactor was 15 kPa.

4.6 hours after the start of the catalyst filling, when the catalyst filling in the dipleg became 1.7 vol%, and when the filling amount of the catalyst into the fluidized bed reactor became 66 tons, the flow gas flowing into the reactor was increased to set the total flow rate F to 30X 10 ³ Nm ³ /h。

After the flow-use gas had increased (5.3 hours), the temperature T in the reactor was 280 ℃, the overhead pressure P was 15kPa, and the gas flow rate U was 0.31m/s.

Finally the catalyst filling can be completed with a catalyst filling time of 6.1 hours. The amount of the catalyst charged after completion of the catalyst charging was 109 tons, and it was confirmed that almost the entire amount of the catalyst was charged into the reactor.

(ammoxidation reaction after filling the catalyst)

The ammoxidation reaction was carried out under the same conditions as in example 1 using a fluidized bed reactor (see fig. 1) filled with a catalyst for a fluidized bed. While the reaction temperature was detected by thermocouple thermometers provided at a plurality of locations during the reaction, temperature unevenness (hot spots) during the reaction was not observed, and the catalyst was in a good flow state. The average yield of acrylonitrile was 77.1%.

Comparative example 1

(filling of catalyst into fluidized bed in reactor)

In the same manner as in example 1, the filling of the fluidized bed catalyst into the fluidized bed reactor (see fig. 1) was started. Air was used as a gas for fluidizing and a gas for transporting a catalyst to the fluidized bed reactor, and the total flow rate F of these gases was set to 40 × 10 ³ Nm ³ H is used as the reference value. The gas flow rate U in the reactor at the start of filling (filling time 0 hour) was 0.48m/s. The catalyst was charged into the fluidized bed reactor under the conditions that the temperature T in the fluidized bed reactor was 420 ℃ and the top pressure P in the fluidized bed reactor was 26 kPa.

The total flow rate F of the introduced gas is set constant without increasing. The catalyst filling in the dipleg after 1.1 hour was 1.3 vol%. The catalyst filling was finally completed with a catalyst filling time of 2.1 hours. The amount of the catalyst charged after completion of the catalyst charging was 105 tons, and it was found that about 5 mass% of the catalyst supplied to the charging was scattered outside the reactor.

(ammoxidation reaction after filling the catalyst)

The ammoxidation reaction was carried out under the same conditions as in example 1 using a fluidized bed reactor (see fig. 1) filled with a catalyst for a fluidized bed. During the reaction, the reaction temperature was detected by thermocouple thermometers provided at a plurality of locations, and as a result, temperature unevenness (hot spot) was observed in the reactor, and it was found that the flow state of the catalyst was deteriorated. The average yield of acrylonitrile was 73.4%, and a catalyst that had been reduced and deteriorated (discolored) was observed from the reactor that had been stopped after the reaction.

Comparative example 2

(filling of the fluidized bed into the reactor with catalyst)

In the same manner as in example 1, the filling of the fluidized bed catalyst into the fluidized bed reactor (see fig. 1) was started. Air was used as a gas for fluidizing and a gas for transporting a catalyst to the fluidized bed reactor, and the total flow rate F of these gases was set to 3 × 10 ³ Nm ³ H is used as the reference value. The gas flow rate U in the reactor at the start of filling (filling time 0 hour) was 0.04m/s. The catalyst was charged into the fluidized bed reactor under the conditions that the temperature T in the fluidized bed reactor was 420 ℃ and the top pressure P in the fluidized bed reactor was 2 kPa.

In the catalyst filling, the total flow rate F of the introduced gas is constant without increasing. The catalyst filling in the dipleg after 7.9 hours was 1.3 vol%. The final catalyst fill required 17.8 hours of catalyst fill time. The amount of the catalyst charged after completion of the catalyst charging was 110 tons, and it was confirmed that almost the entire amount of the catalyst was charged into the reactor, but since the charging time was required to be extended by about 5 to 12 hours compared to examples 1 and 2, the energy consumption required for heating the temperature in the reactor was in the meantime (for example, when the charging time was extended by 5 hours, 400Nm was used for propylene supplied as fuel ³ X 5 hr =2000Nm ³ The amount of use of) increases.

(ammoxidation reaction after filling the catalyst)

The ammoxidation reaction was carried out under the same conditions as in example 1 using a fluidized bed reactor (see fig. 1) filled with a catalyst for a fluidized bed. While the reaction temperature was detected by thermocouple thermometers provided at a plurality of locations during the reaction, temperature unevenness (hot spots) during the reaction was not observed, and the catalyst was in a good flow state. The average yield of acrylonitrile was 77.3%, but as described above, a filling time was required, and thus a loss of opportunity occurred during the production of acrylonitrile.

As is clear from the above examples and comparative examples, in the initial stage of catalyst filling until the immersion pipe at the lower part of the cyclone in the reactor is filled with a certain amount of catalyst, the gas flow rate in the reactor is reduced, and the gas flow rate in the reactor is increased from the middle of catalyst filling to perform the reaction between catalyst filling and the reaction after filling in the reactor, whereby the amount of catalyst scattered to the outside of the reactor can be suppressed, and the reaction can be performed with a high yield of the target product without causing deterioration in the flowing state of the catalyst.

Description of the symbols

1: fluidized bed reactor

2: catalyst hopper

10: fluidized bed reactor

11: catalyst fluidized bed

12: cyclone separator

13: inlet port

14: immersion tube

15: gas outflow pipe

16: gas supply conduit

17: branch pipe part

18: pipe connecting part

19: gas dispersion plate

20: gas supply port

X: gas containing catalyst

Y: gas containing oxygen

Z: raw material gas

X ₁ : catalyst and process for preparing same

X ₂ : the catalyst-transporting gas.

Claims

1. A method of filling a fluidized bed reactor with a catalyst, comprising the steps of: setting an effective sectional area of the fluidized bed reactor to Bm ² ]Setting the temperature in the fluidized bed reactor to T DEG C]And the total flow rate of the gas introduced into the fluidized bed reactor is Fnm ³ /h]And setting the pressure at the top of the fluidized bed reactor to P [ kPa ]]And substituting into the following formula (1), with respect to the obtained gas flow velocity U [ m/s ] in the fluidized bed reactor]Starting to fill the catalyst into the fluidized bed reactor, and then increasing the U;

u = (F/B × ((273 + T))/273)/((101 + P)/101))/3600. Cndot. Formula (1).

2. The method of claim 1, wherein the value of T is from 100 ℃ to 500 ℃.

3. The method of claim 1 or 2, wherein the U is increased by increasing the F.

4. The method of any one of claims 1-3, wherein the U is increased by altering at least one of the T and the P.

5. The process of any one of claims 1 to 4, wherein a catalyst return is provided within the fluidized bed reactor,

the catalyst return unit is a part for returning the catalyst recovered in the fluidized bed reactor to the fluidized bed reactor from a position vertically below a position where the catalyst is recovered,

the amount of catalyst is calculated from the pressure difference of at least 2 locations having different positions in the vertical direction inside the catalyst return unit, and when the amount of catalyst reaches a predetermined value, the U is increased.

6. The method according to any one of claims 1 to 5, wherein the gas is at least one of a fluidizing gas for fluidizing the catalyst and a catalyst-transporting gas for transporting the catalyst to a fluidized-bed reactor.

7. The method according to any one of claims 1 to 6, wherein in the step of increasing the U, the U is increased by 2% or more and 200% or less relative to the U at the start of filling.

8. The method according to any one of claims 1 to 6, wherein in the step of increasing the U, the U is increased by 4% or more and 150% or less with respect to the U at the start of filling.

9. The method according to any one of claims 1 to 8, wherein the catalyst is a catalyst for producing a nitrile compound.

10. A method for producing a nitrile compound, characterized in that: a process comprising performing the method of claims 1 to 9.

11. A method for producing a nitrile compound, characterized in that: the production of a nitrile compound is continued after the method of claims 1 to 9 is performed.