JP5712005B2 - Method for producing acrylonitrile - Google Patents

Description

  The present invention relates to a method for producing acrylonitrile by performing a gas phase catalytic ammoxidation reaction using a fluidized bed reactor.

A method for producing acrylonitrile by vapor-phase catalytic ammoxidation of propane or propylene with molecular oxygen in the presence of ammonia is widely known as an “ammoxidation process”.
So far, in order to produce acrylonitrile obtained by this ammoxidation reaction in a suitable yield, many proposals have been made such as optimization of the operating conditions of the fluidized bed reactor and improvement of the catalyst for ammoxidation. is there.

For example, Patent Document 1 discloses that the contact efficiency is improved and the yield of nitrile is increased by setting the solid matter density (that is, the catalyst bed density) and the gas flow rate in a fluidized bed reactor to specific ranges. It is described.
Patent Document 2 describes that a nitrile compound can be obtained in high yield by improving the composition of the catalyst for ammoxidation.

Japanese Patent Laid-Open No. 10-152463 Japanese Patent Laid-Open No. 2002-136872

As described in Patent Document 1 or 2, the effect of improving the yield of nitrile can be obtained by optimizing the flow state of the catalyst in the fluidized bed reactor and the composition of the catalyst. However, according to the study by the present inventor, it was found that not only the state in the fluidized bed reactor but also the state of the feed of the source gas affects the reaction.
For example, when the feed temperature of ammonia as a raw material is too high, the sparger blowing temperature in the reactor becomes too high, and the sparger is caused by ammonia decomposition (generally, decomposition starts at 150 ° C.). This easily promotes the nitriding phenomenon and may shorten the life of the sparger.
When the feed temperature of propylene or propane, which is a raw material, and ammonia is too low, once evaporated propylene or propane and ammonia are condensed in the pipe, and mist is generated. When the generated mist-like propylene or propane and ammonia are fed as they are, the flow meter installed in the feed pipe gives a false indication, and further, the raw gas is unevenly distributed due to rapid evaporation in the reactor. Arise.
For example, as a result of the generation of propylene mist, the amount of unreacted propylene increases in the portion where the raw material propylene is excessive, and in the portion where the propylene is insufficient, the other raw materials become surplus, resulting in a decrease in the acrylonitrile yield. .

  The present invention has been made in view of the above circumstances, and by appropriately controlling the feed state of the raw material gas, propylene or propane contained in the raw material feed gas and ammonia are prevented from condensing, and thus the flow meter It is an object of the present invention to provide a production method and a production apparatus that can prevent a decrease in the yield of acrylonitrile caused by an erroneous instruction.

  The present inventor prevents condensation of propylene, propane and ammonia contained in the feed gas by controlling the feed temperature and feed pressure of the feed gas fed to the fluidized bed reactor within an appropriate range, and the flow meter error. The present inventors have found that the instructions can be effectively prevented and have made the present invention.

That is, this invention is a manufacturing method of acrylonitrile as shown below.
[1]
A method for producing acrylonitrile by performing a gas phase catalytic ammoxidation reaction using a fluidized bed reactor,
A method for producing acrylonitrile, wherein a feed temperature of the source gas is set to 0 ° C. or more and 30 ° C. or less, and a feed pressure of the source gas is set lower than a vapor pressure at the feed temperature.
[2]
The said raw material gas is a manufacturing method of the acrylonitrile of the said [1] description containing propylene or propane and ammonia.
[3]
The production method according to [1] or [2] above, wherein the raw material gas is heated and / or kept warm by a pipe that feeds the raw material gas to the fluidized bed reactor.
[4]
The production method according to [3] above , wherein mist and / or drain in the raw material gas is removed by piping for feeding the raw material gas to the fluidized bed reactor.
[5]
The production method according to the above [3] or [4], wherein reclaimed water obtained in the acrylonitrile production process is used as a heat source for heating and / or keeping the source gas warm.
[6]
An apparatus for producing acrylonitrile having a fluidized bed reactor,
A feed pipe for raw material gas is connected to the fluidized bed reactor, and heating means and / or heat retaining means are provided in the feed pipe,
The feed temperature of the source gas is adjusted to 0 ° C. or more and 30 ° C. or less and the feed pressure of the source gas is adjusted to be less than the vapor pressure at the feed temperature by the heating means and / or the heat retaining means, Introduced into the fluidized bed reactor,
An apparatus for producing acrylonitrile, wherein a mist separator is provided in the feed pipe, and mist contained in the source gas is discharged from the mist separator.
[7]
The apparatus for producing acrylonitrile according to [6] above, wherein regenerated water obtained in the acrylonitrile production process is supplied to the heating means and / or the heat retaining means as a heat source.

  According to the production method of the present invention, it is possible to prevent the condensation of propylene or propane and ammonia, and to effectively prevent the decrease in the yield of acrylonitrile caused by the erroneous indication of the flow meter.

It is a flowchart which shows an example of the manufacturing apparatus of this embodiment schematically. It is a flowchart which shows roughly an example of the apparatus around the evaporator of this embodiment.

  Hereinafter, a form for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

The method for producing acrylonitrile in the present embodiment is a method for producing acrylonitrile by performing a gas phase catalytic ammoxidation reaction using a fluidized bed reactor, wherein the feed temperature of the raw material gas is 0 ° C. or higher and 30 ° C. or lower. In addition, the feed pressure of the source gas is set to be lower than the vapor pressure at the feed temperature.
The acrylonitrile production apparatus in the present embodiment is an acrylonitrile production apparatus having a fluidized bed reactor, wherein a feed pipe for a raw material gas is connected to the fluidized bed reactor, and a heating means and / or Alternatively, a heat retaining means is provided, and the feed temperature of the source gas is 0 ° C. or higher and 30 ° C. or lower and the feed pressure of the source gas is less than the vapor pressure at the feed temperature by the warming means and / or the heat retaining means. And the raw material gas is introduced into the fluidized bed reactor.

In this embodiment, “source gas” includes propylene or propane and ammonia. In the production of acrylonitrile by an ammoxidation reaction, air (oxygen) is also used as a raw material. However, adjusting the feed pressure and feed temperature of air to the above ranges is not an essential requirement in this embodiment.
Since propylene or propane is a raw material, it is particularly preferable to have a high purity, but other components are preferably contained in an amount of 10% by mass or less, more preferably 1% by mass or less, and even more preferably 0.1% by mass or less. Good. Similarly, ammonia having a high purity is particularly preferred, but other components may preferably be contained in an amount of 1% by mass or less, more preferably 0.1% by mass or less, and still more preferably 0.01% by mass or less.

FIG. 1 is a flowchart schematically showing an example of an acrylonitrile production apparatus according to the present embodiment.
The apparatus shown in FIG. 1 cleans the raw material evaporators 5 and 6, the reactor 1 to which the raw material gas evaporated in the evaporators 5 and 6 is fed, and the reaction gas containing acrylonitrile generated in the reactor 1. A quenching tower 2 for cooling and a pipe (line) connecting them are provided. The reactor is generally roughly classified into a fixed bed reactor and a fluidized bed reactor, and a fluidized bed reactor is used as a reactor used in the ammoxidation reaction of this embodiment.

  The raw materials are supplied to the evaporators 5 and 6 in a liquid state, and are evaporated in the evaporators 5 and 6. Although it does not specifically limit as a heat source, It is preferable to use the regenerated water which generate | occur | produces in an acrylonitrile manufacturing process. Propylene or propane is supplied to the propylene / propane evaporator 5 from the propylene / propane tank 3 and evaporated in the evaporator 5, and then propylene gas or propane gas is introduced into a mist separator 10 b provided downstream of the evaporator 5. Is done. By passing through the mist separator 10b, the mist condensed with propylene or propane entrained in the gas is removed and introduced into the propylene / propane preheater 8. Liquid ammonia is supplied to the ammonia evaporator 6 from the ammonia tank 4, and the evaporated ammonia gas is introduced into the ammonia preheater 9 via the mist separator 10a.

Propylene gas or propane gas is superheated in a propylene / propane preheater 8. The heat source of the preheater 8 is not particularly limited, but it is preferable to use reclaimed water generated in the acrylonitrile production process.
The preheater 8 is not particularly limited as long as it can heat or keep the raw material gas, and may be, for example, a double tube or a steam trace. Steam is preferably used as the heating source for the double pipe and the steam trace, and more preferably, the temperature can be controlled by adjusting the flow rate of the heat source with a control valve as shown in FIG.

  A temperature detector 13b is provided downstream of the preheater 8, and the temperature of the overheated propylene gas or propane gas is measured. The position where the temperature detector 13b is provided may be between the preheater 8 and the reactor 1, but from the viewpoint of precisely controlling the temperature of the gas introduced into the reactor 1, in the vicinity of the reactor 1 inlet. Preferably there is. In the present specification, “in the vicinity of the inlet” means a position within 10 m upstream from the merging point of propylene or propane and ammonia, excluding restrictions on the location due to equipment or piping. The temperature of propylene or propane gas detected by the temperature detector 13b is preferably 0 ° C. or higher and 30 ° C. or lower, and more preferably 10 ° C. or higher and 25 ° C. or lower. If the outside air temperature is about −5 to 35 ° C., the temperature within 10 m upstream from the junction is maintained at 0 ° C. or higher and 30 ° C. or lower, so that the temperature of the raw material gas is changed from the piping to the reactor inlet. Since the inventor has empirically found that the temperature can be maintained within the range, it is not always necessary to measure the temperature immediately before the inlet. However, when a temperature drop is expected after passing through the temperature detector 13b and before being introduced into the reactor 1 in view of the outside air temperature, the temperature range may be set higher by about 5 ° C.

  In the manufacturing method of the present embodiment, the feed temperature of the source gas is set to 0 ° C. or higher and 30 ° C. or lower. Here, the “feed temperature of the raw material gas” is a temperature obtained by averaging the temperature of propylene gas or propane gas at the inlet of the reactor 1 and the temperature of ammonia gas described later. As described above, the temperature in the temperature detector 13b is preferably 0 ° C. or higher and 30 ° C. or lower, and preferably 5 ° C. or higher and 35 ° C. or lower when a temperature drop is expected before being introduced into the reactor 1. Thus, the temperature of the raw material gas can be controlled within this range in both the piping and the reactor, and aggregation of the raw material gas can be prevented. By preventing aggregation in the piping, the flow rate of the raw material gas can be accurately measured, and by preventing aggregation at the inlet of the reactor, it is possible to prevent unevenness in the distribution of the raw material gas in the reactor.

  The temperature of the propylene gas or propane gas can be controlled by adjusting the flow rate of reclaimed water that is a heat source of the propylene / propane preheater 8 with the control valve 11b. Ammonia is the same as described above, and the ammonia gas that has passed through the mist separator 10 a is overheated by the ammonia preheater 9. The temperature of the overheated ammonia gas is such that the temperature detected by the temperature detector 13a near the inlet of the reactor 1 is preferably 0 ° C. or higher and 30 ° C. or lower, more preferably 10 ° C. or higher and 25 ° C. or lower. The flow rate of the reclaimed water that is the heat source of the ammonia preheater 9 is adjusted by the control valve 11a.

  Pressure detectors 14b and 14a are provided downstream of the preheaters 8 and 9, and the pressures of the overheated propylene gas or propane gas and ammonia gas are measured. The position where the pressure detectors 14b and 14a are provided may be between the preheaters 8 and 9 and the reactor 1. From the viewpoint of precisely controlling the pressure of the gas introduced into the reactor 1, the reactor The vicinity of one inlet is preferable. The pressure of the overheated propylene gas or propane gas is adjusted to be lower than the vapor pressure at the feed temperature by opening / closing operation (opening adjustment) of the control valve 12b. The same applies to ammonia, and the pressure of the overheated ammonia gas is adjusted to be lower than the vapor pressure at the feed temperature by opening / closing operation (opening adjustment) of the control valve 12a. By maintaining the feed pressure of each gas below the vapor pressure at the feed temperature, mist generation due to gas condensation is effectively prevented.

  In the manufacturing method of the present embodiment, the feed pressure of the raw material gas is set lower than the vapor pressure at the feed temperature. Here, similarly to the “feed gas feed temperature”, the “feed gas feed pressure” is an average of the pressure of propylene gas or propane gas at the inlet of the reactor 1 and the pressure of ammonia gas. The gases merge after passing through the pressure detectors 14a and 14b and flow into the reactor. It is preferable to design the pipe diameter and the like so as to maintain the pressure after the merge. In this case, by setting the pressure of each gas in the pressure detectors 14a and 14b installed before the merge to be lower than the vapor pressure, the gases are merged while maintaining the pressure, and the raw material gas is fed to the reactor. .

  To measure “feed gas feed temperature” and “feed gas feed pressure”, it is more direct to measure temperature and pressure after propylene gas or propane gas and ammonia gas merge. Prior to merging, the temperature and pressure of each gas may be measured and averaged. When measuring temperature and pressure after merging, the flow rate of each gas cannot be grasped. If the temperature and pressure of propylene gas, propane gas, and ammonia gas are measured and controlled before the merge, the temperature and pressure of each gas are grasped and the gas is merged while preventing mist formation in the piping. Is preferable in that the temperature and pressure can be indirectly controlled to prevent mist formation during piping and feeding. However, in this case, in order to make it difficult for the temperature and pressure to change between the measurement and the feed, heat insulation is applied to the pipes between them, the measurement location is close to the reactor side, etc. It is preferable to devise the design.

  Propylene or propane gas and ammonia gas merge after passing through the flow rate detectors 15 a and 15 b and are fed to the reactor 1. If a part of the raw material gas is mist at the time of detecting the flow rate, each flow rate detector 15a, b cannot normally detect the mist content but only the gas content. As a result, the flow rate detectors 15a, 15b indicate erroneously. As a result, the yield of acrylonitrile is reduced.

  The reactor 1 contains a catalyst, and an ammoxidation reaction proceeds by contacting the fed raw material gas to produce acrylonitrile. The reaction gas containing acrylonitrile is distilled from the outlet at the top of the reactor 1 and introduced into the quenching tower 2.

  A sampling line is branched between the outlet of the reactor 1 and the inlet of the quenching tower 2, and a reaction gas sampling valve 7 is connected to the end of the sampling line. The sampling line may be provided at a position where it can be sampled without any change in properties after the reaction gas flows out of the reactor 1, and there is substantially no change between the reactor 1 and the quenching tower 2. The attachment position is not particularly limited. The reaction gas sampling valve 7 is a valve for manually connecting a reaction gas sampling container, and it is preferable that sampling is performed periodically. If the collected reaction gas is analyzed by gas chromatography or the like, the carbon number of acrylonitrile contained in the reaction gas can be calculated from the measured value. Therefore, the total number of carbon atoms of the reaction gas calculated at the same time is calculated. The yield of the target acrylonitrile can be calculated by dividing it into a percentage value.

  The reaction gas containing acrylonitrile flowing out from the reactor 1 is fed to the quenching tower 2, washed and cooled, and finally becomes a product acrylonitrile through a recovery step and a purification step.

FIG. 2 is a flowchart schematically showing an example of an apparatus around the evaporators 5 and 6 according to the present embodiment.
A fuel tank 20 is connected to the propylene / propane evaporator 5 via a drain evaporator 16. When propylene / propane contains high-boiling substances, the high-boiling substances that do not evaporate are stored in the evaporator 5 as drainage. When the drain is concentrated in the propylene / propane evaporator 5, the boiling point rises and the operation cannot be continued. Therefore, cleaning to remove the drain is necessary. In order to prevent such a situation, the drain is preferably always discharged to the propylene / propane evaporator 16 through the pipe 18. In the propylene / propane evaporator 16, propylene in the drain is evaporated again, merged with the propylene gas evaporated in the evaporator 5, and fed to the reactor 1. The remaining drain is finally extracted to the fuel tank 20 through the pipe 18.

  On the other hand, in the ammonia evaporator 6, the moisture contained as impurities in the ammonia may not be evaporated and may remain in the form of drain as a liquid. In order to prevent the drain from concentrating in the ammonia evaporator 6, Is always discharged to the ammonia drain evaporator 17 through the pipe 19. In the ammonia drain evaporator 17, the ammonia in the drain is evaporated again, merged with the ammonia gas evaporated in the evaporator 6, and fed to the reactor 1. The remaining drain is finally extracted to the waste water tank 21 through the pipe 19.

  The drain outlet is not particularly limited and can be arbitrarily determined according to the situation. For example, a fuel tank or a waste water tank may be used as in the present embodiment, or it may be once received in a waste water pit or directly fed to a waste water incinerator for processing.

  According to the production method of the present embodiment, it is possible to prevent the condensation of propylene, propane, and ammonia, and to effectively prevent a decrease in the yield of acrylonitrile caused by an erroneous instruction of the flow meter.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.
In the examples and comparative examples, the acrylonitrile yield was measured as follows. First, the reaction gas was sampled in a gas state and a liquid state. As a sampling method in the gas state, the reactive gas sampling valve 7 and a reactive gas sampling cylinder (not shown) having a capacity of 500 mL were connected with a hose, and after replacing with the reactive gas, the reactive gas was sampled for about 10 seconds. On the other hand, the sampling method in the liquid state is such that the reaction gas sampling valve 7 and a 500 mL absorption bottle (not shown) containing 400 mL of nitric acid inside are immersed in ice water and connected to a hose. The reaction gas was absorbed for minutes.
Subsequently, the reaction gas collected in the collection cylinder was analyzed by gas chromatography (model: Shimadzu GC-2014, detector: TCD). On the other hand, the reaction gas absorption liquid collected in the absorption bottle was analyzed by gas chromatography (model: Shimadzu GC-14B, detector: FID).
From these measured values, the number of carbons of acrylonitrile contained in the reaction gas was calculated, and the yield of acrylonitrile was calculated by dividing this carbon number by the total number of carbons of the reaction gas calculated simultaneously. .
In the following examples and comparative examples, the temperature and pressure of each gas were measured, and the average was used as the feed temperature and feed pressure of the source gas. In addition, since the piping from the temperature and pressure detector to the reactor inlet is kept warm with a heat insulating material and the distance of the piping is shortened (10 m), the temperature and pressure of the detector are regarded as the temperature and pressure of the reactor inlet, respectively. It was.

[Example 1]
An apparatus for producing acrylonitrile having the same configuration as the apparatus shown in FIGS. 1 and 2 was used. Propylene and ammonia were used as raw materials, and their purity was 95% by mass or more and 99% by mass or more, respectively.
Propylene is fed from the propylene / propane tank 3 to the propylene / propane evaporator 5 in a liquid state and evaporated, and then the propylene / propane preheater 8 is adjusted so that the temperature detected by the temperature detector 13b is 25 ° C. Overheated. As the heat source of the preheater 8, reclaimed water produced in the acrylonitrile production process was used. The overheated propylene opens the control valve 1 2 b so that the pressure detected by the pressure detector 14 b is 3.0 K / G, which is equal to or lower than the vapor pressure (10.7 K / G) of prepylene at 25 ° C. The degree was adjusted.
The same applies to ammonia. After ammonia is fed from the ammonia tank 4 to the ammonia evaporator 6 in a liquid state and evaporated, ammonia using reclaimed water as a heat source so that the temperature detected by the temperature detector 13a is 25 ° C. The preheater 9 was used for overheating. Superheated ammonia is the pressure detected by the pressure detector 14a, the control valve 1 2 a so as to 3K / G is less than the vapor pressure of 25 ° C. Ammonia (9.3K / G) opening Adjustments were made.
These source gases merged after passing through the flow rate detectors 15a and 15b, and were fed to the reactor 1 to produce acrylonitrile by performing an ammoxidation reaction under general conditions.

  The reaction gas flowing out from the top of the reactor 1 was sampled before the quenching tower 2 and analyzed by gas chromatography. Analysis was performed twice a week for one month. As a result, the average yield of acrylonitrile was about 81.2%.

  In addition, since the flow rate detectors 15a and 15b did not erroneously instruct, it is considered that there was no scattering of source gas mist and drain.

[Example 2]
Except for adjusting the conditions of the raw material gas so that the temperature detected by the propylene temperature detector 13b is 10 ° C. and the temperature detected by the ammonia temperature detector 13a is 10 ° C., The raw material gas was fed to the reactor 1 to carry out an ammoxidation reaction.
The vapor pressures of propylene and ammonia at 10 ° C. were 6.9 K / G and 5.3 K / G, respectively.

  The reaction gas flowing out from the top of the reactor 1 was sampled before the quenching tower 2 and analyzed by gas chromatography. Analysis was performed twice a week for one month. As a result, the average yield of acrylonitrile was about 81.4%.

  In addition, since the flow rate detectors 15a and 15b did not erroneously instruct, it is considered that there was no scattering of source gas mist and drain.

[Example 3]
Except for adjusting the conditions of the raw material gas so that the temperature detected by the propylene temperature detector 13b is 0 ° C and the temperature detected by the ammonia temperature detector 13a is 0 ° C, The raw material gas was fed to the reactor 1 to carry out an ammoxidation reaction.
The vapor pressures of propylene and ammonia at 0 ° C. were 4.9 K / G and 3.4 K / G, respectively.

  The reaction gas flowing out from the top of the reactor 1 was sampled before the quenching tower 2 and analyzed by gas chromatography. Analysis was performed twice a week for one month. As a result, the average yield of acrylonitrile was about 81.0%.

  In addition, since the flow rate detectors 15a and 15b did not erroneously instruct, it is considered that there was no scattering of source gas mist and drain.

[Comparative Example 1]
Except for adjusting the conditions of the source gas so that the temperature detected by the propylene temperature detector 13b is 50 ° C. and the temperature detected by the ammonia temperature detector 13a is 50 ° C. It fed to the reactor 1 and ammoxidation reaction was performed.
The vapor pressures of propylene and ammonia at 50 ° C. were 19.8 K / G and 19.7 K / G, respectively.

The reaction gas flowing out from the top of the reactor 1 was sampled before the quenching tower 2 and analyzed by gas chromatography. Analysis was carried out between one month at a frequency of twice a week. As a result, the average yield of acrylonitrile was about 79.9%.

  In addition, since the flow rate detectors 15a and 15b did not erroneously instruct, it is considered that there was no scattering of source gas mist and drain.

[Comparative Example 2]
The same procedure as in Example 1 was carried out except that the conditions of the raw material gas were adjusted so that the temperature detected by the propylene temperature detector 13b was -1 ° C and the temperature detected by the ammonia temperature detector 13a was -1 ° C. Then, it was fed to the reactor 1 to carry out ammoxidation reaction.
The vapor pressures of propylene and ammonia at -1 ° C. were 4.7 K / G and 3.2 K / G, respectively.

  The reaction gas flowing out from the top of the reactor 1 was sampled before the quenching tower 2 and analyzed by gas chromatography. Analysis was performed twice a week for one month. As a result, the average yield of acrylonitrile was about 80.2%.

  Since the flow rate detectors 15a and 15b showed a flow rate smaller than the actual usage amount, it is considered that a part of the raw material gas was condensed and mist was generated, which was accompanied by the gas and fed.

[Comparative Example 3]
After propylene is fed from the propylene / propane tank 3 to the propylene / propane evaporator 5 in a liquid state and evaporated, the propylene / propane preheater 8 is adjusted so that the temperature detected by the temperature detector 13b is 5 ° C. Overheated. The overheated propylene opens the control valve 1 2 b so that the pressure detected by the pressure detector 14b is 3.0 K / G which is lower than the vapor pressure (5.8 K / G) of propylene at 5 ° C. The degree was adjusted.
Ammonia was fed from the ammonia tank 4 in a liquid state to the ammonia evaporator 6 and evaporated, and then overheated by the ammonia preheater 9 so that the temperature detected by the temperature detector 13a was 5 ° C. Superheated ammonia was carried out the opening degree adjustment of the control valve 1 2 a so that the pressure detected by the pressure detector 14a becomes 4.3k / G is the same pressure as the vapor pressure of 5 ° C. Ammonia . These source gases merged after passing through the flow rate detectors 15a and 15b, and were fed to the reactor 1 to produce acrylonitrile by an ammoxidation reaction under general conditions.

  Since the feed pressure of the ammonia gas was the same as the vapor pressure, mist was generated a lot, the difference between the flow rate detector 15a and the actual amount used was large, and it was impossible to continue stable operation.

  The results in Examples and Comparative Examples are shown in Table 1.

  DESCRIPTION OF SYMBOLS 1 ... Reactor, 2 ... Quenching tower, 3 ... Propylene / propane tank, 4 ... Ammonia tank, 5 ... Propylene / propane evaporator, 6 ... Ammonia evaporator, 7 ... Reaction gas sampling valve, 8 ... Propane / propylene preheater , 9 ... Ammonia preheater, 10a, 10b ... Mist separator, 11a, 11b, 12a, 12b ... Control valve, 13a, 13b ... Temperature detector, 14a, 14b ... Pressure detector, 15a, 15b ... Flow rate detector, 16 ... propylene / propane drain evaporator, 17 ... ammonia drain evaporator, 18 ... propylene / propane drain pipe, 19 ... ammonia drain pipe, 20 ... fuel tank, 21 ... waste water tank

Claims (7)

A method for producing acrylonitrile by performing a gas phase catalytic ammoxidation reaction using a fluidized bed reactor,
A method for producing acrylonitrile, wherein a feed temperature of the source gas is set to 0 ° C. or more and 30 ° C. or less, and a feed pressure of the source gas is set lower than a vapor pressure at the feed temperature.   The method for producing acrylonitrile according to claim 1, wherein the source gas includes propylene or propane and ammonia.   The manufacturing method of Claim 1 or 2 which heats and / or heat-retains the said source gas with piping which feeds the said source gas to the said fluidized bed reactor. The manufacturing method of Claim 3 which removes the mist and / or drain in the said source gas with piping which feeds the said source gas to the said fluidized bed reactor. The manufacturing method of Claim 3 or 4 using the reclaimed water obtained at the manufacturing process of acrylonitrile as a heat source which heats and / or heat-retains the said source gas . An apparatus for producing acrylonitrile having a fluidized bed reactor,
A feed pipe for raw material gas is connected to the fluidized bed reactor, and heating means and / or heat retaining means are provided in the feed pipe,
The feed temperature of the source gas is adjusted to 0 ° C. or more and 30 ° C. or less and the feed pressure of the source gas is adjusted to be less than the vapor pressure at the feed temperature by the heating means and / or the heat retaining means, Introduced into the fluidized bed reactor,
An apparatus for producing acrylonitrile, wherein a mist separator is provided in the feed pipe, and mist contained in the source gas is discharged from the mist separator.   The apparatus for producing acrylonitrile according to claim 6, wherein regenerated water obtained in an acrylonitrile production process is supplied to the heating means and / or the heat retaining means as a heat source.