JP5236258B2 - Easily polymerizable substance handling equipment - Google Patents

Description

  The present invention relates to an apparatus for handling easily polymerizable substances.

  In devices (reactors, distillation towers, etc.) that handle easily polymerizable substances ((meth) acrolein, (meth) acrylic acid, etc.), polymers of easily polymerizable substances are likely to be generated. In particular, the easily polymerizable substance tends to stay on the inner wall surface of the nozzle projecting from the apparatus main body and the easily polymerizable substance contact surface of the lid that seals the opening of the nozzle, and the polymer easily adheres. Therefore, it is necessary to frequently stop the operation of the apparatus and perform maintenance (cleaning, etc.) of the apparatus.

The following apparatus has been proposed as an apparatus in which the retention of the easily polymerizable substance in the nozzle and the clogging of the nozzle due to the polymer are suppressed.
An oxidation reactor having a reactor main body and a nozzle protruding from the reactor, the oxidation reactor having means for supplying an inert gas into the nozzle and means for heating the nozzle (Patent Document 1) .

However, in the oxidation reactor, since only the nozzle is heated, there is a problem that the easily polymerizable substance tends to stay on the easily polymerizable substance contact surface of the lid, and the polymer is easily attached. Therefore, it is necessary to frequently stop the oxidation reactor and perform maintenance (cleaning, etc.) of the oxidation reactor.
JP 2003-231661 A

  The present invention provides an easily polymerizable material handling apparatus that can be stably operated for a long period of time.

An easily polymerizable substance handling apparatus of the present invention is an apparatus for handling an easily polymerizable substance, the apparatus main body, a nozzle protruding from the apparatus main body, a lid for sealing the opening of the nozzle, Heating means that heats the lid, and the heating means is installed on the non-contact surface side of the easily polymerizable material of the rupture disk, and is heated in the middle so that the opening faces the rupture disk the heating air introduced from the introduction tube, and wherein the means der Rukoto for heating the rupture disk by applying directly to said rupture disk from the easily polymerizable substance non-contact surface side of the rupture disk.

  The easily polymerizable material handling apparatus of the present invention can be operated stably for a long period of time.

  In the present specification, (meth) acrolein means acrolein or methacrolein, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylate means acrylate or methacrylate. .

  An easily polymerizable substance handling apparatus is an apparatus for handling (manufacturing, refining, etc.) an easily polymerizable substance. Examples of the easily polymerizable substance handling apparatus include a reactor used for producing an easily polymerizable substance, a tank, a heat exchanger, an absorption tower, etc. associated therewith; a distillation column or an evaporator used for purification of the easily polymerizable substance , And a heat exchanger, a tank, and the like associated therewith.

  Examples of the reactor include a multitubular reactor. A multi-tubular reactor is a state in which a plurality of reaction tubes filled with a catalyst, a shell containing the reaction tubes, channels provided on the inlet and outlet sides of the reaction tube, and both ends of the reaction tube are bundled By fixing to the shell, a tube plate that partitions the shell and the channel is provided.

  An easily polymerizable substance is a substance that easily polymerizes to form a polymer. Examples of the easily polymerizable substance include a polymerizable vinyl compound. Examples of the polymerizable vinyl compound include unsaturated aldehydes ((meth) acrolein, etc.), unsaturated carboxylic acids ((meth) acrylic acid, etc.), alkyl (meth) acrylates (methyl (meth) acrylate, normal Butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, etc.), ring (Meth) acrylates having a structure (cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, etc.)), vinyl group Yes (meth) acrylates (allyl (meth) acrylate etc.), hydroxy group-containing (meth) acrylates (hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate etc.), alkoxy group-containing (meth) acrylates (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, etc.), polyfunctional (meth) acrylates (ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,3 -Butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc.), carboxylic acid-containing (meth) acrylates 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, etc.), dialkylaminoethyl (meth) acrylates (dimethylaminoethyl (meth) acrylate, dimethylaminoethyl ( (Meth) acrylate methyl chloride salt, dimethylaminoethyl (meth) acrylate benzyl chloride salt, diethylaminoethyl (meth) acrylate, etc.), halogenated alkyl (meth) acrylates (trifluoroethyl (meth) acrylate, heptadecafluorodecyl ( (Meth) acrylate, etc.).

  The easily polymerizable substance also includes a liquid containing the easily polymerizable substance. Examples of the liquid containing the easily polymerizable substance include, for example, a mixture of the easily polymerizable substance and a by-product during the production or purification of the easily polymerizable substance; the easily polymerizable substance and the easily polymerizable substance. And a mixture with a reactive solvent (water, toluene, hexane, etc.).

  The nozzle is a tubular member protruding from the apparatus main body, and the base end communicates with the apparatus main body and is joined to the apparatus main body. Examples of the nozzle include a rupture disk attaching nozzle, a measuring instrument attaching nozzle, an inspection window attaching nozzle, and a manhole nozzle.

  The lid body seals the opening at the tip of the nozzle. Examples of the lid include a rupture disk, a measuring instrument (such as a pressure gauge), an inspection window, and a lid.

The heating means is means for heating the lid. As the heating means, a heating fluid introduction port (for example, reference numeral 28 in FIG. 1) for introducing a heating fluid into a pipe (for example, reference numeral 22 in FIG. 1) connected to the nozzle through a lid body; Examples include piping, hot water piping, and electric heaters. The heating means is preferably a means for heating the lid from the non-polymerizable substance non-contact surface side of the lid.
As a heating method by the heating means, a heating fluid is introduced into a pipe connected to the nozzle through a heating fluid introduction port, and the heating fluid is brought into contact with the lid; steam piping, hot water piping, an electric heater or the like is used on the lid. The method of making it contact directly is mentioned.

Examples of the heating fluid include heated air, heated inert gas, and steam.
When the lid is a rupture disk, the discharge pipe (the pipe provided with the heating fluid inlet) is connected to the nozzle facing upward, so that when the heating fluid is brought into direct contact with the lid from the discharge pipe side, the heating fluid As such, heated air or heated inert gas that does not generate condensed water is preferable.

The flow rate of the heating fluid is not particularly limited, but is preferably ^{50~2000Nm 3 / hr, 100~1000Nm 3 /} hr are more preferred. When the flow rate is too small, the polymerization preventing effect is lowered because of insufficient heating. If the flow rate is too high, the polymerization preventing effect can be obtained, but it becomes uneconomical.
The means for heating the heating fluid is not particularly limited, and examples thereof include steam piping, hot water piping, and an electric heater.

Hereinafter, a multitubular reactor will be described as an example of the easily polymerizable substance handling apparatus of the present invention.
FIG. 1 is a cross-sectional view showing the vicinity of a rupture disk mounting nozzle in a multitubular reactor. The multi-tubular reactor 10 (easily polymerizable substance handling device) seals the reactor main body 12 (device main body), the nozzle 14 protruding from the upper channel 46 of the reactor main body 12, and the opening of the nozzle 14 And a discharge pipe 22 connected to the nozzle 14 by a bolt 18 and a nut 20 via the rupture disk portion 16, and a nozzle heating means 24 provided around the nozzle 14.

  A replacement gas introduction port 26 for introducing a replacement gas into the nozzle 14 is provided on the side wall of the nozzle 14, and a heated air introduction port 28 (heating) for introducing heated air into the discharge tube 22 on the side wall of the discharge tube 22. Means). Further, the heated air introduction port 28 extends into the discharge pipe 22 so that the heated air directly hits the rupture disk, and is heated halfway bent so that the opening faces the rupture disk (heating means). ) Is preferably connected.

The rupture disk portion 16 includes a rupture disk 32 (lid body) having a dome portion 30 that swells toward the nozzle 14 side, and two holders 34 and 36 that sandwich the periphery of the rupture disk 32.
In the rupture disk portion 16, when the pressure inside the reactor main body 12 is abnormally increased, the dome portion 30 of the rupture disk 32 is buckled and reversed, and the rupture disk portion 16 is provided in the holder 36 on the side opposite to the nozzle 14 side. The dome portion 30 collides with the letter-shaped knife 38, and the rupture disk 32 is ruptured and opened. Thereby, the excess pressure inside the reactor main body 12 is discharged to the outside through the discharge pipe 22.

  Examples of the replacement gas include a gas that suppresses the polymerization of the easily polymerizable substance, and examples thereof include dry air and inert gas (nitrogen gas, rare gas, carbon dioxide gas, etc.). By introducing the replacement gas into the nozzle 14 from the replacement gas inlet 26, the replacement gas is filled in the nozzle 14, and the entrance of the easily polymerizable substance into the nozzle 14 is suppressed. Even if the polymerizable substance stays, the polymerization is suppressed.

  Examples of the nozzle heating means 24 include a steam pipe, a hot water pipe, and an electric heater. By providing the nozzle heating means 24, the nozzle 14 is heated, the easily polymerizable substance adhering to the inner wall of the nozzle 14 is vaporized, and the retention of the easily polymerizable substance in the nozzle 14 is suppressed.

  As shown in FIG. 2, the reactor main body 12 includes a plurality of reaction tubes 40 filled with a catalyst, a shell 42 that houses the reaction tubes 40, a lower channel 44 provided on the inlet side of the reaction tubes 40, By fixing the upper channel 46 provided on the outlet side of the reaction tube 40 and the shell 42 in a state where both ends of the reaction tube 40 are bundled together, the shell 42 and the lower channel 44, and the shell 42 and the upper channel 46 are combined. And a tube plate 48 for partitioning. A heat medium outlet 50 and a heat medium inlet 52 are provided on the side wall of the shell 42, a source gas inlet 54 is provided in the lower channel 44, and a reaction gas outlet 56 is provided in the upper channel 46. Yes.

  Next, production of (meth) acrolein and production of (meth) acrylic acid using the multitubular reactor 10 will be described.

Production of (meth) acrolein:
The catalyst is filled in the reaction tube 40 of the multitubular reactor 10.
A heating medium is introduced into the shell 42 of the multitubular reactor 10, the temperature inside the reaction tube 40 is raised to a predetermined reaction temperature, and the raw material is introduced into the lower channel 44 of the multitubular reactor 10 from the raw material gas inlet 54. Gas is supplied, and the source gas is passed through the reaction tube 40 at a predetermined space velocity.
The reaction gas containing (meth) acrolein discharged from the reaction tube 40 passes through the upper channel 46 and is discharged from the reaction gas discharge port 56.

  While supplying the raw material gas into the multi-tube reactor 10, the replacement gas is introduced into the nozzle 14 protruding from the upper channel 46 from the replacement gas inlet 26, and the nozzle 14 is filled with the replacement gas. Further, steam is introduced into nozzle heating means 24 provided around the nozzle 14 to heat the nozzle 14. Further, heated air is introduced from the heated air inlet 28 into the discharge pipe 22 connected to the nozzle 14 via the rupture disk portion 16, and the rupture disk 32 is heated from the non-polymerizable substance non-contact surface side of the rupture disk 32. To do.

Examples of the catalyst include multi-component oxide catalyst particles containing molybdenum, bismuth and iron.
The raw material gas is 1 to 20% by volume of one or more gases selected from the group consisting of isobutylene, t-butanol and methyl-t-butyl ether, 1 to 20% by volume of molecular oxygen, and 0 to 40% of water vapor. %, And a mixed gas containing an inert gas (nitrogen, carbon dioxide, etc.).
The source gas is 5 to 20% by volume of one or more gases selected from the group consisting of isobutylene, t-butanol and methyl-t-butyl ether, 5 to 20% by volume of molecular oxygen, and 0 to 30 volumes of water vapor. %, And a mixed gas containing an inert gas (nitrogen, carbon dioxide, etc.).

The reaction temperature is usually 300 to 450 ° C.
As the space velocity, 500 to 3000 hr ⁻¹ is preferable.
The temperature of the heated air introduced from the heated air inlet 28 is preferably 60 to 160 ° C.

Production of (meth) acrylic acid:
(Meth) acrylic acid is produced in the same manner as in the production of (meth) acrolein, except that the catalyst, raw material gas, and reaction temperature are changed.

Examples of the catalyst include catalyst particles made of a phosphomolybdic acid-based heteropoly acid or a metal salt thereof.
As the source gas, a mixed gas containing 1 to 20% by volume of (meth) acrolein, 1 to 20% by volume of molecular oxygen, 1 to 40% by volume of water vapor, and an inert gas (nitrogen, carbon dioxide, etc.). Can be mentioned.
The reaction temperature is usually 200 to 400 ° C.

  Since the multi-tubular reactor 10 described above includes the heated air inlet 28 for introducing heated air for heating the rupture disk 32, the easy polymerization that adheres to the easily polymerizable substance contact surface of the rupture disk 32. Sexual substances are vaporized. Therefore, the easily polymerizable substance does not easily stay on the easily polymerizable substance contact surface of the rupture disk 32, and the polymerized substance does not easily adhere. Therefore, the frequency of maintenance (cleaning etc.) of the multitubular reactor 10 decreases. As a result, it is not necessary to frequently stop the multitubular reactor 10, and the multitubular reactor 10 can be stably operated for a long period of time.

  Further, in the multi-tube reactor 10 described above, the rupture disk 32 is heated from the non-contact surface side of the easily polymerizable material of the rupture disk 32, so that heated air is contained in the multi-tube reactor 10. It does not enter the reaction gas.

  In addition, the easily polymerizable substance handling apparatus of the present invention is not limited to the multi-tubular reactor 10 shown in FIG. 1, and includes a nozzle protruding from the apparatus main body, and a lid for sealing the opening of the nozzle. Any device may be used as long as it has heating means for heating the lid.

Examples are shown below.
[Example 1]
Production of methacrolein:
A multi-component oxide catalyst particle containing molybdenum, bismuth and iron was filled in the reaction tube 40 of the multi-tube reactor 10.
A heating medium is introduced into the shell 42 of the multitubular reactor 10, the temperature inside the reaction tube 40 is raised to 340 ° C., and the isobutylene is introduced into the lower channel 44 of the multitubular reactor 10 from the source gas inlet 54. 5% by volume, 12% by volume of molecular oxygen, 10% by volume of water vapor, and 73% by volume of nitrogen are supplied, and the source gas is passed through the reaction tube 40 at a space velocity of 1000 hr ⁻¹ . It was.
The reaction gas containing methacrolein discharged from the reaction tube 40 was discharged from the reaction gas outlet 56 of the upper channel 46.

While supplying the raw material gas into the multi-tubular reactor 10, dry air was introduced into the nozzle 14 protruding from the upper channel 46 from the replacement gas inlet 26 at a rate of 300 NL / hr. Further, steam was introduced into nozzle heating means 24 (steam piping) provided around the nozzle 14. In addition, heated air at 130 to 140 ° C. is introduced from the heated air inlet 28 into the discharge pipe 22 connected to the nozzle 14 via the rupture disk portion 16 at a rate of 300 Nm ³ / hr to facilitate polymerization of the rupture disk 32. The rupture disk 32 was heated from the non-contact surface side of the sexual substance.

  After the production of methacrolein was continuously performed for 1000 hours, the nozzle 14 and the rupture disk 32 were confirmed, and adhesion of a polymer was not confirmed.

[Example 2]
Production of methacrylic acid:
In the reaction tube 40 of the multitubular reactor 10, catalyst particles made of phosphomolybdic acid heteropolyacid were packed.
The heat medium is introduced into the shell 42 of the multitubular reactor 10, the temperature inside the reaction tube 40 is raised to 290 ° C., and the raw gas is introduced into the lower channel 44 of the multitubular reactor 10 from the source gas inlet 54. A raw material gas consisting of 5% by volume of methacrolein produced in Step 1, 10% by volume of molecular oxygen, 15% by volume of water vapor, and 70% by volume of nitrogen is supplied, and the raw material gas is supplied at a space velocity of 1000 hr ⁻¹ . The reaction tube 40 was passed through.
The reaction gas containing methacrylic acid discharged from the reaction tube 40 was discharged from the reaction gas outlet 56 of the upper channel 46.

While supplying the raw material gas into the multi-tubular reactor 10, dry air was introduced into the nozzle 14 protruding from the upper channel 46 from the replacement gas inlet 26 at a rate of 300 NL / hr. Further, steam was introduced into nozzle heating means 24 (steam piping) provided around the nozzle 14. In addition, heated air at 130 to 140 ° C. is introduced from the heated air inlet 28 into the discharge pipe 22 connected to the nozzle 14 via the rupture disk portion 16 at a rate of 300 Nm ³ / hr to facilitate polymerization of the rupture disk 32. The rupture disk 32 was heated from the non-contact surface side of the sexual substance.

  After the production of methacrylic acid was continuously performed for 1000 hours, the nozzle 14 and the rupture disk 32 were confirmed, and adhesion of a polymer was not confirmed.

  The easily polymerizable substance handling apparatus of the present invention is useful as an apparatus for producing and purifying easily polymerizable substances, and in particular, a reactor for producing (meth) acrolein, (meth) acrylic acid, etc., and purification. Useful as a distillation column.

It is sectional drawing which shows the vicinity of the rupture disk attachment nozzle in the multitubular reactor which is an example of the easily polymerizable substance handling apparatus of this invention. It is sectional drawing which shows an example of a multitubular reactor.

Explanation of symbols

10 Multi-tube reactor (Easily polymerizable material handling equipment)
12 Reactor body (apparatus body)
14 Nozzle 28 Heated air inlet (heating means)
29 Heated air introduction pipe (heating means)
32 Rupture disc (lid)

Claims (1)

An apparatus for handling easily polymerizable substances,
An apparatus main body, a nozzle projecting from the apparatus main body, a rupture disk for sealing the opening of the nozzle, and a heating means for heating the rupture disk ,
The heating means is installed on the non-polymerizable material non-contact surface side of the rupture disk, and heated air introduced from a heated air introduction pipe bent in the middle so that an opening faces the rupture disk. Ru means der heating said rupture disk by applying the easily polymerizable substance non-contact surface side of the disc directly to said rupture disk, the easily polymerizable substance handling apparatus.

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