TWI486214B - Temperature control method for fluidized bed reactor - Google Patents

Description

Temperature control method for fluidized bed reactor

The present invention relates to a temperature control method for a fluidized bed reactor, and more particularly to a temperature control method for more finely controlling the temperature in the reactor when a gas phase exothermic reaction is carried out using a fluidized bed reactor.

Industrially produced by a gas phase exothermic reaction for various synthetic resins. A fluidized bed reactor is widely used in the production of useful monomers for synthetic fibers. As a representative example of the gas phase exothermic reaction which is industrially carried out, a sequential oxidation reaction such as a partial oxidation reaction or an ammonia oxidation reaction in the presence of ammonia can be mentioned. In the successive oxidation reaction, the oxidation stability of the partial oxidation product as the target product is generally not so high, and thus the target product is successively reacted as the reaction proceeds, that is, the reaction conversion rate increases. As a result, there is a tendency that the total oxidation product increases and the selectivity of the target product decreases. Therefore, the yield of the target product obtained as a product of the conversion ratio and the selectivity has a maximum value at a certain conversion rate. For example, in Non-Patent Document 1, it is disclosed that acrylonitrile is produced by an ammoxidation reaction of propylene, and generally, when the conversion ratio is 85 to 95%, the yield is the highest value. Therefore, in order to economically and more advantageously manufacture the target product, it is extremely important to control the conversion rate of the reaction within a preferable range. Of course, the control of the conversion rate is not limited to the oxidation reaction, and is also true for the general gas phase exothermic reaction.

On the other hand, as one of the advantages of the fluidized bed reactor, it can be exemplified that the heat in the reactor moves faster and the reaction temperature is relatively easier to control than other reactor forms such as a fixed bed reactor. . For use When the fluidized bed reactor is subjected to a gas phase exothermic reaction, in order to control the temperature of the reactor, a method is generally employed in which a heat removal tube group is vertically disposed in the fluidized bed reactor, and a fluid serving as a cooling medium is passed through the heat removal tube. Group to recover heat from the reaction.

As a method of controlling the temperature in the reactor based on the temperature detected by the temperature detector, for example, Patent Document 1 discloses a method of flowing a cooling medium at a variable speed in at least one heat removal tube, thereby adjusting the flow rate thereof. A temperature-regulating method for controlling a temperature of a fluidized bed reactor and a fluidized bed reactor. Further, Patent Document 2 discloses a method of controlling the temperature by adjusting the flow rate of the liquid mixed in the vapor at a substantially constant flow rate when the liquid and the steam are mixed as a cooling medium.

[Non-Patent Document 1] Tanaka Tiejin, "Progress in Manufacturing Technology of Acrylonitrile", Japan Chemical Association Monthly Report, Japan Chemical Industry Association, Society, October 1971, p551-561

[Patent Document 1] WO 95/21692 Booklet

[Patent Document 2] US Patent No. 2697334

Here, the conversion rate of the raw material of the gas phase exothermic reaction depends on the activity of the catalyst, and the conversion rate increases as the activity of the catalyst increases. Further, the catalytic activity depends on the reaction temperature, and in addition to the exception of the enzyme reaction, in general, the catalytic activity increases as the reaction temperature increases. Further, for example, in the case of an oxidation reaction, when the partial oxidation product is compared with the energy of the complete oxidation product, the complete oxidation product (for example, CO ₂ ) is more stable, and of course, if the complete oxidation reaction contributes Ascending, the heat release of the entire reaction system will increase. This conclusion is also true for the general gas phase exothermic reaction.

Therefore, in the gas phase exothermic reaction, it is assumed that when the reaction temperature rises for some reason, there is a tendency to exhibit the following cyclic behavior: 1) the catalyst activity increases as the temperature rises; 2) the reaction The conversion rate increases as the activity of the catalyst increases, so that the reaction proceeds successively; 3) the amount of the actually reacted in the supplied raw material increases, and the contribution of the more stable product increases with the progress of the successive reaction. Thereby, the calorific value per unit time of the entire reaction system increases; 4) As a result, the reaction temperature further rises. Of course, in the case where the reaction temperature is lowered, the reverse cycle behavior is also exhibited. In either case, the local temperature of the reactor is dissipated to cause the temperature distribution in the reactor, and further, In extreme cases, the temperature of the entire reactor is dissipated, which may cause thermal runaway of the reactor or stop of the reaction. Therefore, in the gas phase exothermic reaction, fine control of the reaction temperature is of course extremely important for economically and more advantageously producing a target product, and is extremely important for stably continuing the reaction.

Thus, in view of the importance of temperature control in the gas phase exothermic reaction, previous temperature control is not sufficient depending on the reaction, and finer temperature control is required. In view of the above circumstances, it is an object of the present invention to provide a temperature control method which can more precisely control the temperature in a flow reactor when a gas phase exothermic reaction is carried out using a fluidized bed reactor.

The inventors of the present invention conducted intensive studies on the above problems, and as a result, have found that the present invention can be more precisely controlled by the following method, which is carried out by using a fluidized bed reactor to carry out a gas phase exothermic reaction. a temperature control method comprising the steps of: the fluidized bed reactor having a heat removal tube and a temperature detector in an effective sectional area of not more than 20 square meters, wherein the temperature detected by the temperature detector deviates from a set temperature At the time, the heat removal capability of the heat removal tube is adjusted to control the temperature of each of the above effective sectional areas.

That is, the present invention is as follows.

[1] A temperature control method for performing a temperature control method in a gas phase exothermic reaction using a fluidized bed reactor, and comprising the steps of: the above-mentioned fluidized bed reactor having an effective sectional area of not more than 20 square meters each The heat removal tube and the temperature detector are configured to adjust the heat removal capability of the heat removal tube to control the temperature of each of the effective sectional areas when the temperature detected by the temperature detector deviates from the set temperature.

[2] The temperature control method according to [1] above, wherein in the temperature range in which the gas phase exothermic reaction is carried out, the total heat of reaction is 50 to 2500 kJ/mol (raw material), and the temperature is related to the temperature of the total reaction heat. The differential coefficient is 0.2~40kJ/mol (raw material). K.

[3] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is It is a gas phase ammoxidation reaction using propane and/or propylene as a raw material, and the reaction product is acrylonitrile.

[4] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is one or more selected from the group consisting of n-butane, 1-butene, 2-butene, butadiene, and benzene. As a gas phase oxidation reaction of a raw material, the reaction product is maleic anhydride.

[5] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using i-butene and/or i-butane as a raw material, and the reaction product is a Acrylonitrile.

[6] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is a gas phase oxidation reaction using o-xylene and/or naphthalene as a raw material, and the reaction product is phthalic anhydride.

[7] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is a gas phase alkylation reaction using phenol and methanol as a raw material, and the reaction product is 2,6-xylenol and/or Or o-cresol.

[8] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using methane and/or methanol as a raw material, and the reaction product is hydrocyanic acid (HCN).

[9] The temperature control method according to [1] or [2] above, wherein the gas phase exothermic reaction A gas phase ammoxidation reaction using one or more selected from the group consisting of ethane, ethylene, and ethanol as a raw material, and the reaction product is acetonitrile.

[10] A production method using a method for producing a target compound of a fluidized bed reactor, and comprising the steps of: (a) supplying a raw material to the fluidized bed reactor filled with a catalyst to carry out a gas phase exothermic reaction; And (b) the fluidized bed reactor has a heat removal tube and a temperature detector in an effective sectional area of not more than 20 square meters, and the above-mentioned removal is adjusted when the temperature detected by the temperature detector deviates from the set temperature The heat removal capability of the heat pipe to control the temperature of each of the above effective sectional areas.

According to the temperature control method of the present invention, the temperature in the fluidized bed reactor can be more finely controlled when the gas phase exothermic reaction is carried out using the fluidized bed reactor.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as the present embodiment) will be described in detail. The present invention is not limited to the embodiments described below, and various modifications can be made without departing from the spirit and scope of the invention.

The temperature control method of the present embodiment is a temperature control method for performing a gas phase exothermic reaction using a fluidized bed reactor, which comprises the steps of: the above-mentioned fluidized bed reactor having an effective sectional area of not more than 20 square meters each The heat pipe and the temperature detector adjust the heat removal capability of the heat removal pipe to control each time when the temperature detected by the temperature detector deviates from the set temperature The temperature of the above effective sectional area.

In the present embodiment, the fluidized bed reactor is virtually divided into effective sectional areas of not more than 20 square meters, and a heat removal tube and a temperature detector are provided in each divided effective sectional area to control the temperature. The temperature can be controlled by a heat removal tube that is close to a temperature detector that detects a difference from the set temperature and that has a large influence on the temperature of the detector installation portion. Further, if the heat removal is performed by the heat removal tube that is close to the temperature detector that detects the difference from the set temperature, the time from the execution of the control until the actual effect occurs is short. Therefore, it is inferred that excessive adjustment or too small adjustment due to the time delay can be prevented, so that the temperature can be prevented from being emitted, and as a result, the temperature in the reactor can be more finely controlled.

As the effective sectional area of the virtual division, it is preferably 15 square meters or less, more preferably 10 square meters or less. Here, the "effective sectional area" means a sectional area in which a content other than the inner insert portion of the fluidized bed reactor actually flows.

In the embodiment, the temperature detector and the heat removal tube are disposed in an effective sectional area of not more than 20 square meters, and when the temperature detected by the temperature detector deviates from the set temperature, the heat removal capability of the heat removal tube is adjusted. To control the temperature of each of the above effective sectional areas. The adjustment of the heat removal capability of the heat pipe can be automatically performed using a regulator, or can be manually performed after appropriate judgment.

Here, the "set temperature" means a temperature in a fluidized bed reactor which can give a good conversion ratio and a yield of a target product in a gas phase exothermic reaction, and the set temperature can be determined according to the reaction to be carried out. Set it arbitrarily.

Temperature detection set within each effective sectional area of no more than 20 square meters If the number of the devices is one or more, a plurality of them may be provided. In the case where a plurality of temperature detectors are provided in the divided effective sectional area, only one of the detectors may be used, or two or more detectors may be selected and an operation of averaging the plurality of detection temperatures may be performed. Here, it is a matter of course that when a plurality of detection temperatures are averaged, the average processing is performed in each of the effective sectional areas divided into sections, and the effective sectional area cannot be crossed and the detection temperature is performed. average.

The position of the temperature detector is not particularly limited as long as it can stably measure the temperature of the reactor, and can be disposed on the thick layer of the catalyst according to the purpose. Thin layer. Gas outlets, etc. The form of the temperature detector to be provided is not particularly limited, and a detector of a commonly used form can be used, for example, a thermocouple or a resistance temperature sensor can be used.

In the present embodiment, at least one heat removal tube for removing the heat of reaction to control the temperature in the reactor is provided in each effective sectional area of not more than 20 square meters. The heat removal tube can also have the purpose of recovering the energy generated by the reaction. The shape of the heat removal pipe to be provided is not particularly limited as long as it can be appropriately set in the reactor. However, in terms of the ease of handling the material and the ease of processing, the material for piping is generally The steel pipe is combined with the steel pipe joint to form a plurality of connected U-shaped. The material of the heat pipe is not particularly limited, and may be a self-supporting material such as JIS G-3454, depending on the conditions to be used, that is, the temperature, pressure, and corrosiveness of the fluid contacted by the cooling medium or the reaction gas. The piping materials specified in G-3458 and G-3459, and the steel pipe joints specified in JIS B-2311 and the like are freely selected and used.

The heat removal tube adjusts the heat removal capacity according to the supply speed of the raw material or the ability of the heat removal tube due to dirt or the like to decrease. Therefore, it is preferable to divide the heat removal pipe having a capability of a fixed margin with respect to the necessary heat removal into a plurality of series, so that the total heat removal capability can be roughly adjusted. Here, the series means a valve that can open and close the flow of the cooling medium, and the group of the heat removal pipe or the heat removal pipe that can be used or not used can be individually set. In addition to the heat removal capability of the heat pipe, it is exposed to the area of the thick layer of the fluidized bed, the area in contact with the thin layer of the fluidized layer, the temperature of the catalyst layer, and the type of cooling medium that circulates. Physical form. Supply temperature. The speed of supply and other factors dominate. Therefore, when the heat removal capability of the heat removal pipe is adjusted, one or more of the various physical factors can be arbitrarily set, for example, the supply temperature or the supply speed of the cooling medium is changed, whereby the capability can be adjusted. Further, the heat transfer area is changed by increasing or decreasing the number of the heat removal tubes, and as a result, the overall heat removal capability can be adjusted.

The total heat removal capacity of the heat pipe is not particularly limited as long as it is a heat (required ability) to remove heat from the heat of reaction generated, etc., and it is preferably 130% or more of the necessary capacity. It is more than 150% of the necessary capacity, and then it is better than 180% of the necessary capacity. In terms of preventing the device from being too large, the total heat removal ability of the heat pipe is preferably 300% or less of the necessary capacity, more preferably 270% or less of the necessary capacity, and further preferably 240% or less of the necessary capacity. Since the number of series of heat removal tubes increases, the adjustment of the heat removal capability tends to be easier. Therefore, it is preferable to provide 5 series or more, and more preferably 8 series or more, and thus it is good. It is set to 10 series or more. By switching the use/non-use of the plurality of series, the total heat removal capability can be roughly adjusted and used.

The cooling medium circulating in the heat removal pipe is not particularly limited as long as it can achieve the necessary heat removal capability, and it is preferably a liquid which evaporates at the operating temperature of the reactor, more preferably water, and thus is good. It is water pressurized to 0.5~5MPa (measured pressure). By using the liquid which evaporates at the operating temperature of the reactor as a cooling medium, the heat removal by the latent heat of evaporation can be utilized, so that the total heat transfer coefficient of the heat removal tube can be relatively high. Therefore, the heat removal amount per unit surface area of the heat pipe is increased, so that the necessary number of heat removal pipes can be reduced. Also, the vapor of the obtained cooling medium can be used again as a cooling medium.

The cooling medium is not only a liquid, but preferably a heat removal tube using a gas as a cooling medium, and further preferably a heat removal tube as described below, that is, using a liquid as a cooling medium, and evaporating the cooling medium A part is recovered as a liquid-vapor mixed gas-liquid phase flow, and the generated steam is further used as a cooling medium and recovered as superheated steam.

The fluidized bed reactor is generally in the form of an ascending flow, that is, the catalyst particles are kept in a fluidized state by the upward flow of the gas introduced from the lower portion of the reactor, but in the present embodiment, it is not limited to this form. It can also be in the form of a downflow or other means.

In order to perform finer temperature control of the fluidized bed reactor in which the gas phase exothermic reaction is carried out more finely, it is desirable to keep the generated heat as stable as possible; and to cause the heat transfer in the fluidized layer to proceed rapidly. In order to stably maintain the generated heat, it is preferred to keep the reaction conditions such as the supply rate of the raw material and the reaction pressure as constant as possible to stably carry out the reaction. For the flow The heat transfer within the layer proceeds rapidly, and the flow state of the fluidized layer must be well maintained. It is generally known that the flow state of the fluidized bed is governed by the gas flow rate (apparent velocity) or the catalyst particle size and the like. The gas flow rate is not particularly limited as long as it can maintain the flow state of the fluidized layer well. The catalyst may be used as long as it is used as a catalyst for the fluidized bed reactor, but the weight average particle diameter is preferably from 20 to 100 m, more preferably from 30 to 80 μm, and even more preferably from 40 to 60 μm. Further, the content of the fine powder having a particle diameter of 44 μm or less (so-called good grain size) is preferably from 10 to 70% by weight, and further preferably classified as A particles in the Geldart powder classification chart.

The gas phase exothermic reaction in the present embodiment is not particularly limited, and examples thereof include a gas phase ammoxidation reaction in which acrylonitrile is produced using propane and/or propylene as a raw material, and is selected from the group consisting of n-butane and 1-butene. A gas phase oxidation reaction in which maleic anhydride is produced as a raw material of one or more of 2-butene, butadiene, and benzene; and methyl group is produced using i-butene and/or i-butane as a raw material Gas phase ammoxidation reaction of acrylonitrile; gas phase oxidation reaction of phthalic anhydride with o-xylene and/or naphthalene as raw material; 2,6-xylenol and/or phenol and methanol as raw materials A gas phase alkylation reaction of o-cresol; a gas phase ammoxidation reaction of hydrocyanic acid (HCN) using methane and/or methanol as a raw material.

The heat of reaction of the gas phase exothermic reaction varies depending on the reaction. For example, the heat of reaction of propylene to ammonia to acrylonitrile is 520 kJ/mol (propylene), and the heat of reaction of propane with ammonia to form acrylonitrile is 637 kJ/mol (propane). However, the actual response is concurrency. Successive reactions produce CO ₂ , CO or other by-products. The total heat of reaction including the side reaction can be determined in consideration of the contribution rate of each reaction (the yield of each product).

For example, in the case of propane combustion to generate heat of reaction between CO ₂ and water or CO and water, each 1 mol of propane is respectively 2043 kJ/mol (propane) and 1194 kJ/mol (propane), so if it is set under certain conditions When 100 mol of propane is reacted with ammonia and oxygen, 80 mol of propane is reacted (reaction rate: 80%) to produce 50 mol of acrylonitrile (yield 50%), 60 mol of CO ₂ (yield 20%), and 30 mol of CO ( The yield was 10%. The total heat of reaction under this condition was determined to be 637 × 0.5 + 2043 × 0.2 + 1194 × 0.1 = 846.5 (kJ / mol). It is clear from the calculation process that the total heat of reaction varies depending on the reaction rate of the raw materials and the contribution rate of each concurrent reaction (distribution of the product), and thus the total heat of reaction depends on the reaction conditions. The total heat of reaction is not particularly limited, but if it is too large, the amount of heat to be removed may increase, which may make it difficult to control, which may cause temperature distribution in the reactor, and, in the extreme case, may cause The heat of the reactor is out of control, so when the reaction conditions are selected, it is preferred to make the total heat of reaction as small as possible. Specifically, it is preferred to select the reaction conditions in such a manner that the raw material to be supplied per 1 mol is preferably 50 to 2500 kJ/mol (raw material), more preferably 70 to 2000 kJ/mol (raw material), especially Good is 100~1500kJ/mol (raw material).

On the other hand, in the gas phase exothermic reaction, the stability of the target product is not so high, and the sequential reaction of the target product proceeds as the reaction progresses, that is, the reaction conversion rate increases, so that the target product is present. The tendency of the selection rate to decline. Here, the reaction conversion rate depends on the activity of the catalyst, and the conversion rate increases as the activity increases. Moreover, the activity of the catalyst depends on the anti At the temperature, generally, the activity rises as the reaction temperature rises. Therefore, when the reaction temperature rises due to some reason, the overall reaction heat increases due to an increase in the amount of the reaction and the progress of the successive reactions.

For example, when the conditions of the preceding paragraph only increase the temperature by 5 ° C and the other conditions are completely unchanged, if the change is made, 82.5 mol of propane reacts (reaction rate 82.5%) in the supplied 100 mol of propane. 50.3 mol of acrylonitrile (yield 50.3%), 64.5 mol of CO ₂ (yield 21.5%), and 32.1 mol of CO (yield 10.7%), the total heat of reaction under this condition is 637×0.503+2043× 0.215 + 1194 x 0.107 = 887.4 (kJ / mol). The rate of change of the total heat of reaction can be expressed as a partial differential coefficient relating to the temperature of the total heat of reaction. In this case, by linear approximation around the temperature, it is found to be (887.4-846.5) ÷ 5 = 8.2 ( kJ/mol.K). It can be determined from the calculation process that the partial differential coefficient related to the temperature of the total reaction heat varies depending on the reaction temperature, the reaction rate of the raw materials, the contribution rate of each concurrent reaction (the yield of each product), and the like, and therefore the partial differential coefficient depends on Under the reaction conditions. When the rate of change of the total reaction heat is too large, the control of the heat balance and the reaction temperature become unstable, which becomes the cause of the temperature distribution in the reactor, and further, in the extreme case, the thermal runaway of the reactor is caused. Therefore, in this regard, when the reaction conditions are selected, it is preferred to make the rate of change of the total heat of reaction as small as possible. Specifically, it is preferred to select the reaction conditions in such a manner that the partial differential coefficient related to the temperature of the total reaction heat is 0.2 to 40 kJ/mol (raw material). K, preferably 0.5~30kJ/mol (raw material). K, especially good is 1~10kJ/mol (raw material). K.

[Method of Manufacturing Target Compound]

Moreover, the method for producing a target compound of the present embodiment is a method for producing a target compound using a fluidized bed reactor, which comprises the steps of: (a) supplying a raw material to the fluidized bed reactor filled with a catalyst to carry out a gas phase exothermic reaction; and (b) the fluidized bed reactor has a heat removal tube and a temperature detector in an effective sectional area of not more than 20 square meters each, when the temperature detected by the temperature detector deviates from the set temperature Adjusting the heat removal capability of the heat removal tube to control the temperature of each of the above effective sectional areas.

Step (a) is a step of supplying a raw material to a fluidized bed reactor filled with a catalyst to carry out a gas phase exothermic reaction. Here, the reaction of the gas phase exothermic reaction is the same as the above-mentioned gas phase exothermic reaction, and examples of the raw material include the same materials as those exemplified as the raw materials of the gas phase exothermic reaction. In addition, the catalyst is not particularly limited, and examples thereof include a composite oxide catalyst and the like which are generally used in a gas phase exothermic reaction.

Step (b) is a step as follows: the fluidized bed reactor has a heat removal tube and a temperature detector in an effective sectional area of not more than 20 square meters, and when the temperature detected by the temperature detector deviates from the set temperature Adjust the heat removal capacity of the heat removal tube to control the temperature of each effective sectional area. Here, the step (b) corresponds to the step in the above temperature control method, and is carried out by the same method, whereby the target compound can be produced. The target compound is the same as the target compound exemplified as the gas phase exothermic reaction product.

Fig. 1 shows an example of a fluidized bed reactor of the present embodiment, and Fig. 2 shows a cross-sectional view of the AA' plane of the fluidized bed reactor. If the diameter of the fluidized bed reactor (1) is 6 m, the effective sectional area is about 28 square meters, so no more than The 20 square meter method is divided into two by the imaginary line of the north-south line (a area and b area in Fig. 2). A catalyst flow layer (2) composed of a catalyst is formed inside the fluidized bed reactor (1). A gas containing oxygen (usually air) is supplied from an oxygen guiding tube (3) provided at a lower portion of the reactor, and a gas containing a raw material is supplied from the raw material supply pipe (4). The gas containing the reaction product is withdrawn to the outside of the fluidized bed reactor (1) via the extraction pipe (5).

Inside the fluidized bed reactor (1), a heat removal pipe (6a, 6b) located in the catalyst flow layer (2) and using a liquid as a cooling medium, and a heat removal pipe (7a, 7b) using a gas as a cooling medium are disposed. . Specifically, in the region a of the fluidized bed reactor (1), a heat removal pipe 6a and a heat removal pipe 7a are provided, and a heat removal pipe 6b and a heat removal pipe 7b are provided in the b zone. Further, in Fig. 1, only one series is shown for each heat removal tube, but usually a plurality of series are provided.

In the heat removal tube (6a, 6b) using the liquid, the cooling medium is supplied from the gas-liquid separation container (8) by the cooling medium delivery pump (9). By heat exchange between the catalytic fluidized layer (2) and the heat removal tubes (6a, 6b), a part of the cooling medium is partially evaporated and returned to the gas-liquid separation vessel (8) as a gas-liquid two-phase flow, thereby performing gas-liquid separation. . The amount of liquid cooling medium reduced by evaporation is additionally supplied by the cooling medium addition pipe (10).

A portion of the cooling medium vapor generated in the heat removal tubes (6a, 6b) is supplied to the heat removal tubes (7a, 7b). By the heat exchange between the catalyst flow layer (2) and the heat removal tubes (7a, 7b), the medium vapor is cooled into superheated steam and supplied to the outside of the system through the superheated steam extraction pipe (11).

Temperature detectors (12a, 12b) are provided in the catalyst flow layer (2). Only one temperature detector is shown in Fig. 1, but a plurality of them may be provided. Set In the case where a plurality of temperature detectors are provided, an appropriate detector is selected and averaged and the like is used as the temperature of the fluidized layer. The temperature information detected by the temperature detectors (12a, 12b) is transmitted to the temperature indicator (13a, 13b) to detect the temperatures of the a region and the b region of the fluidized layer, respectively.

As described above, in the a region, the heat removal pipes 6a, 7a are provided, and the heat removal pipes 6b, 7b are provided in the b region, so that the measured value of the temperature detector 12a is reflected to the control of the heat removal capability of the heat removal pipes 6a, 7a, and the temperature detection is performed. The measured value of the device 12b is reflected to the control of the heat removal capability of the heat removal pipes 6b, 7b.

The flow regulating valve (14a, 14b) of the cooling medium is operated according to the difference between the detected temperature of the flowing layer and the set temperature to adjust the flow rate of the cooling medium passing through the heat removing tubes (7a, 7b), thereby adjusting Heat removal capacity of heat pipes (7a, 7b).

In addition to the cooling medium vapor generated in the heat pipes (6a, 6b), the remaining portion of the heat removal pipes (7a, 7b) which are not used is supplied to the outside of the system through the saturated steam extraction pipe (15).

[Examples]

Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited to the examples below.

[Example 1]

The fluidized bed reactor (1) having a diameter of 6.82 m in the form shown in Fig. 1 is filled with fine powder having an average particle diameter of 50 μm composed of molybdenum, vanadium, niobium and tantalum and containing 12% of particles having a particle diameter of 44 μm or less. The composite oxide catalyst is 80 tons. Since oxygen supply pipe (3) supplying air 45000Nm ³ / Hr, from the raw material supply pipe (4) supplied in admixture with 2700Nm ³ / Hr of propane gas 3000Nm ³ / Hr and ammonia, the main producing acrylonitrile.

The effective sectional area of the portion to be removed is approximately 36 square meters, and therefore, as shown in Fig. 2, it is imaginarily divided into two in a manner of 18 square meters each, forming an area a and a area b.

In the catalyst flow layer (2), a 15 series heat removal pipe (6a) is provided in the a region, and the heat removal pipe (6a) is a steel pipe having an outer diameter of 114.3 mm prescribed in JIS G-3458 and JIS B- It is made of a butt-welded 180° short-diameter elbow pipe of the corresponding diameter specified in 2311, and a 15 series (total pipe part total of 1250 m) heat removal pipe (6b) is provided in the b area. In the heat removal tubes (6a, 6b), 800 ton / Hr of water at 235 ° C is supplied from the gas-liquid separation vessel (8), and a part thereof is evaporated, and the temperature is 236 ° C and the pressure is 3 MPa (measurement pressure). Gas-liquid two-phase flow and recovery. The evaporation rate under constant conditions was 5.8%.

An 8 series heat removal tube (7a) is provided in the area a, and the heat removal tube (7a) is made of the same material as the heat removal tubes (6a, 6b), and 8 series are provided in the b area (straight tube portion total) 450m) heat removal tube (7b). In the heat removal tubes (7a, 7b), 17 tons of saturated steam having a temperature of 236 ° C and a pressure of 3 MPa (measured pressure) is supplied, and recovered as superheated steam having a temperature of 370 to 372 ° C, and the saturated water is used. The gas-liquid two-phase flow generated by the steam system from the heat removal tubes (6a, 6b) is separated by the gas-liquid separation vessel (8).

In the flow layer portion of the substantially central position of the a region and the b region, one of the K type thermocouples is provided as a temperature detector (12a, 12b), and the thermoelectric potential is converted by the temperature indicator (13a, 13b) into The temperature signal is detected.

The opening of the flow regulating valve (14a) is adjusted to adjust the ability of the heat removing tube (7a) so that the temperature detected by the temperature indicating meter (13a) is 445 ° C, thereby performing temperature adjustment of the a region. Similarly, the opening degree of the flow regulating valve (14b) is adjusted to adjust the ability of the heat removing tube (7b) so that the temperature detected by the temperature indicating meter (13b) is 445 ° C, thereby performing temperature adjustment of the b region. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 443 ° C, the highest portion was 446.5 ° C, and the temperature difference was 3.5 ° C, and the temperature inside the reactor was well controlled.

[Embodiment 2]

Except for the temperature detector (12a), the average temperature of the thermometer at the south and north of the temperature detector (12a) in the a area is set to the temperature of the area a, except for the temperature detector (12b). The reaction was carried out in the same manner as in Example 1 except that the average temperature at three points of the thermometers in the south and north of the temperature detector (b) was set to the temperature in the b region.

The opening degree of the flow regulating valve (14a) is adjusted to adjust the ability of the heat removing tube (7a) so that the average temperature of the three points of the a region is 445 ° C, thereby performing temperature adjustment of the a region. Similarly, the opening degree of the flow regulating valve (14b) is adjusted to adjust the ability of the heat removing tube (7b) so that the average temperature of the three points of the b region is 445 ° C, thereby performing temperature adjustment of the b region. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 443.8 ° C, the highest portion was 446.1 ° C, and the temperature difference was 2.3 ° C, and the temperature inside the reactor was well controlled.

[Example 3]

In the same layered reactor as in Example 1, 105 tons of a composite oxide catalyst composed of vanadium and phosphorus having an average particle diameter of 60 μm and containing 40% of a fine particle having a particle diameter of 44 μm or less was filled. The oxygen supply pipe (3) is supplied with air of 70000 Nm ³ /Hr, and n-butane 2950 Nm ³ /Hr is supplied from the raw material supply pipe (4) to mainly produce maleic anhydride.

In the same manner as in the first embodiment, the area is divided into the a region and the b region, and the opening degree of the flow rate adjusting valve (14a) is adjusted to adjust the ability of the heat removing tube (7a) so that the temperature detected by the temperature indicator (13a) is 452.5 °C. Thus, the temperature adjustment of the a region is performed. Similarly, the opening degree of the flow regulating valve (14b) is adjusted to adjust the ability of the heat removing tube (7b) so that the temperature detected by the temperature indicating meter (13b) is 452.5 ° C, thereby performing temperature adjustment of the b region. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 451.2 ° C, the highest portion was 454.9 ° C, and the temperature difference was 3.7 ° C, and the temperature inside the reactor was well controlled.

[Example 4]

In the same layered reactor as in Example 1, 300 tons of a composite oxide catalyst composed of iron or vanadium having an average particle diameter of 50 μm and containing 40% of a fine particle having a particle diameter of 44 μm or less was filled. The raw material supply pipe (4) is supplied with a mixed gas of methanol and phenol of 50,000 Nm ³ /Hr, and mainly produces o-cresol and 2,6-xylenol.

In the same manner as in the first embodiment, the area is divided into the a region and the b region, and the opening degree of the flow rate adjusting valve (14a) is adjusted to adjust the ability of the heat removing tube (7a) so that the temperature detected by the temperature indicator (13a) is 330 °C. Thus, the temperature adjustment of the a region is performed. Similarly, adjust the opening of the flow regulating valve (14b) to adjust the heat removal tube The ability of (7b) is such that the temperature detected by the temperature indicator (13b) is 330 ° C, thereby performing temperature adjustment of the b region. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 328.8 ° C, the highest portion was 331.7 ° C, and the temperature difference was 2.9 ° C, and the temperature inside the reactor was well controlled.

[Comparative Example 1]

In the first embodiment, the opening degrees of the flow regulating valves (14a) and (14b) are adjusted to adjust the ability of the heat removing tubes (7a) and (7b) to be detected by the temperature indicating devices (13a) and (13b). The average temperature was 445 ° C to adjust the temperature of the entire reactor. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 441.2 ° C, the highest portion was 449.7 ° C, and the temperature difference was 8.5 ° C, and the temperature inside the reactor was not well controlled.

[Comparative Example 2]

In the first embodiment, it is not assumed that the fluidized bed reactor is divided into two, but the position of the temperature detector is changed in the following manner. That is, one K-type thermocouple is provided at the center of the fluidized bed as a temperature detector (12), and the thermoelectric potential is converted into a temperature signal by a temperature indicator (13) for detection.

The opening of the flow regulating valve (14) is adjusted to adjust the ability of the heat removing tube (7) so that the temperature detected by the temperature indicator (13) is 445 ° C, thereby performing temperature adjustment of the entire reactor. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 440 ° C, the highest portion was 451 ° C, and the temperature difference was 11 ° C, and the temperature inside the reactor was not well controlled.

[Comparative Example 3]

In Embodiment 3, the opening degrees of the flow regulating valves (14a) and (14b) are adjusted to adjust the ability of the heat removing tubes (7a) and (7b) to be detected by the temperature indicating devices (13a) and (13b). The average temperature was 452.5 ° C, so that the temperature of the entire reactor was adjusted. At this time, the temperature at 10 points in the fluidized bed was measured, and the lowest portion was 448.1 ° C, the highest portion was 457.2 ° C, and the temperature difference was 9.1 ° C, and the temperature inside the reactor was not well controlled.

[Comparative Example 4]

In Embodiment 4, the opening degrees of the flow regulating valves (14a) and (14b) are adjusted to adjust the ability of the heat removing tubes (7a) and (7b) to be detected by the temperature indicating devices (13a) and (13b). The average temperature was 330 ° C to adjust the temperature of the entire reactor. At this time, the temperature at 10 points in the fluidized bed was measured. The lowest portion was 326.0 ° C, the highest portion was 334.2 ° C, and the temperature difference was 8.2 ° C. The temperature in the reactor was not well controlled.

From the above results, it is clear that in the gas phase exothermic reaction of Examples 1 and 2 using the temperature control method of the present embodiment, the temperature difference from the set temperature is small at any portion of the reactor, and the reactor is small. The internal temperature is finely controlled within a certain fixed range.

On the other hand, in the gas phase exothermic reaction of Comparative Examples 1, 3 and 4, the average value of the entire reactor was used as the detection temperature, and temperature control was not performed for each effective sectional area of not more than 20 m 2 . Depending on the detection location, the temperature difference from the set temperature is large, so that the temperature inside the reactor cannot be finely controlled.

Further, in the gas phase exothermic reaction of Comparative Example 2, the entire reactor has only one temperature detector, and does not have an effective sectional area of not more than 20 m 2 each. Since the temperature is controlled, the temperature difference from the set temperature is large depending on the detection portion, so that the temperature inside the reactor cannot be finely controlled.

[Industrial availability]

According to the present invention, it is possible to finely control industrial manufacture for various synthetic resins. The temperature of the fluidized bed reactor, which is widely used in the production of a useful monomer, can be stably operated for a long period of time in a temperature range in which the catalyst has the highest yield.

1‧‧‧Mobile layer reactor

2‧‧‧catalyst fluid layer

3‧‧‧Oxygen supply tube

4‧‧‧Material supply pipe

5‧‧‧Reaction to generate gas extraction tube

6a, 6b‧‧‧ Heat removal tubes using liquid cooling media

7a, 7b‧‧‧ Heat removal tubes using gas cooling media

8‧‧‧ gas-liquid separation container

9‧‧‧Cooling media pump

10‧‧‧Additional tube for cooling media

11‧‧‧Superheated steam extraction tube

12a, 12b‧‧‧ Temperature detector

13a, 13b‧‧‧ temperature indicator

14a, 14b‧‧‧ flow control valve (for capacity adjustment)

15‧‧‧Saturated steam extraction tube

Fig. 1 shows an example of a fluidized bed reactor of the present embodiment.

Fig. 2 is a cross-sectional view showing the AA' plane of the fluidized bed reactor, and is a view showing an example in which the fluidized bed reactor is imaginarily divided into two regions of a region and b region in the north-south direction.

1‧‧‧Mobile layer reactor

2‧‧‧catalyst fluid layer

3‧‧‧Oxygen supply tube

4‧‧‧Material supply pipe

5‧‧‧Reaction to generate gas extraction tube

6a, 6b‧‧‧ Heat removal tubes using liquid cooling media

7a, 7b‧‧‧ Heat removal tubes using gas cooling media

8‧‧‧ gas-liquid separation container

9‧‧‧Cooling media pump

10‧‧‧Additional tube for cooling media

11‧‧‧Superheated steam extraction tube

12a, 12b‧‧‧ Temperature detector

13a, 13b‧‧‧ temperature indicator

14a, 14b‧‧‧ flow control valve

15‧‧‧Saturated steam extraction tube

Claims (10)

A temperature control method for performing a temperature control method in a gas phase exothermic reaction using a fluidized bed reactor, and comprising the steps of: the fluidized bed reactor having at least one effective sectional area of not more than 20 square meters each In the above heat removal tube and temperature detector, when the temperature detected by the temperature detector deviates from the set temperature, the heat removal capability of the heat removal tube is adjusted to respectively control the temperature of each of the effective sectional areas. The temperature control method of claim 1, wherein the total reaction heat is 50 to 2500 kJ/mol (raw material) in the temperature range in which the gas phase exothermic reaction is carried out, and the partial differential coefficient related to the temperature of the total reaction heat is 0.2. ~40kJ/mol (raw material). K. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using propane and/or propylene as a raw material, and the reaction product is acrylonitrile. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is gas phase oxidation using one or more selected from the group consisting of n-butane, 1-butene, 2-butene, butadiene, and benzene. The reaction product is maleic anhydride. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using i-butene and/or i-butane as a raw material, and the reaction product is methacrylonitrile. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase oxidation reaction using o-xylene and/or naphthalene as a raw material, and the reaction product is phthalic anhydride. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase alkylation reaction using phenol and methanol as a raw material, and the reaction product is 2,6-xylenol and/or o-cresol. The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using methane and/or methanol as a raw material, and the reaction product is hydrocyanic acid (HCN). The temperature control method according to claim 1 or 2, wherein the gas phase exothermic reaction is a gas phase ammoxidation reaction using one or more selected from the group consisting of ethane, ethylene, and ethanol as a raw material, and the reaction product is acetonitrile. A method for producing a target compound using a fluidized bed reactor, and comprising the steps of: (a) supplying a raw material to the fluidized bed reactor filled with a catalyst to carry out a gas phase exothermic reaction; and (b) the above flowing layer The reactor has a heat removal tube and a temperature detector in an effective sectional area of not more than 20 square meters, and when the temperature detected by the temperature detector deviates from the set temperature, the heat removal capability of the heat removal tube is adjusted to control The temperature of each of the above effective sectional areas.