Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/50—Use of additives, e.g. for stabilisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives
  • C07C67/62—Use of additives, e.g. for stabilisation

Definitions

• the present invention relates to a method for preventing clogging of a device for handling (meth) acrylic acid or an ester thereof, and more particularly, to a nozzle or a pipe connected to a gas phase of an apparatus for handling (meth) acrylic acid or an ester thereof.
• the present invention relates to a method for blowing a gas having a polymerization inhibiting action into a gas to prevent the blockage.
• (meth) acrylic acid is a general term for acrylic acid and methacrylic acid
• (meth) acrylic acid ester is a general name for acrylic acid ester and methacrylic acid ester.
• (Meth) acrylic acid and its esters are compounds that are easily polymerized. In the process of production or use, polymerization often occurs in handling equipment such as distillation towers, evaporators, heat exchangers, tanks, etc., and the operation may have to be stopped.
• a measuring device In order to continuously and stably operate a device that handles (meth) acrylic acid or an ester thereof, it is essential to measure a process state such as pressure, temperature, and liquid level.
• a measuring device In order to measure the process state, a measuring device is installed on the device via a nozzle or the like. The formation of a polymer of (meth) acrylic acid or an ester thereof is observed in the horns and the like, and is particularly observed in the horns connected to the gas phase.
• a polymerization inhibitor such as hydroquinone or a copper-containing compound is introduced into the apparatus.
• these polymerization inhibitors exist only in the liquid phase and not in the gas phase.
• a gas containing an oxygen for example, an inert gas such as nitrogen, carbon dioxide, argon, etc. was mixed with air as a gas having a polymerization inhibiting action. It is known to blow a mixed gas or air into a device.
• Patent Document 1 JP 2003-231661 A
• the present invention has been made in view of the above circumstances, and an object of the present invention is to prevent clogging of a pipe or a pipe connected to a gas phase of a device for treating (meth) acrylic acid or its ester. It is an object of the present invention to provide a method for preventing clogging of a (meth) acrylic acid or ester handling apparatus which can be stopped and operated continuously for a long period of time.
• the present invention has been completed based on the above findings, and the gist of the present invention is to provide a nozzle or a pipe connected to a gas phase of an apparatus for treating (meth) atalinoleic acid or (meth) acrylate.
• the present invention resides in a method for preventing blockage of a handling device. The invention's effect
• FIG. 1 is a partial cross-sectional explanatory view showing an example of a state where a blow-off port for blocking prevention gas is attached to accessory equipment of the present distillation apparatus.
• Acrylic acid can be produced, for example, by any one of the following methods (1) and (3).
• An oxidation step of subjecting propane, propylene and / or acrolein to catalytic gas phase oxidation A collecting step of contacting the obtained acrylic acid-containing gas with water to collect acrylic acid as an aqueous acrylic acid solution, an extracting step of extracting acrylic acid from the obtained aqueous acrylic acid solution using an extraction solvent, and A method comprising a step of removing acrylic acid and a solvent by distilling an acrylic acid-containing liquid to remove a solvent having a low boiling point, and a rectifying step of further distilling.
• (Meth) acrylic acid ester is produced by reacting (meth) acrylic acid with, It can be obtained as a top fraction by an esterich reaction step in which alcohol is reacted, and a step of extracting, evaporating, and distilling the obtained crude (meth) acrylic acid ester solution.
• the obtained (meth) acrylic ester includes methyl (meth) acrylate, ethyl (meth) atalinoleate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) atalinoleate n -Butyl, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isonoel (meth) acrylate, n_noel (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acryl Ethoxylated acid, dimethoxyaminoethyl (meth) acrylate, and the like.
• the (meth) acrylic acid or its ester handling device may be any device used when producing and storing (meth) acrylic acid or its ester.
• the handling device may be any device used when producing and storing (meth) acrylic acid or its ester.
• Devices are included.
• a reactor, a distillation tower, a collecting tower, an evaporator, a heat exchanger, a tank, an extraction tank, a decomposition reactor and the like can be mentioned.
• the distillation column and A decomposition reactor, especially a distillation column is typical.
• distillation tower examples include a perforated-plate tower, a bubble-cap tower, a packed tower, and a combination thereof (for example, a combination of a perforated-plate tower and a packed tower). Are not distinguished, and either can be used.
• Examples of the tray used in the distillation column include a bubble bell tray having a downcomer, a perforated plate tray, a vanoleb tray, a super flux tray, a max flat tray, a dual tray having no downcomer, and the like.
• Packing materials used in distillation columns include those conventionally used in columnar, cylindrical, saddle, spherical, cubic, and pyramidal shapes, as well as high-performance packing in recent years. As regular or irregular packing having a special shape.
• Examples of the ordered packing include gauze type rules such as SULZA-1.PACK manufactured by SURUZA. BROTHERS CO., LTD., SUMITOMO SULZA-1. Filling, regular-type sheet-type packing such as Melapak manufactured by Sumitomo Heavy Industries, Ltd., Technopack manufactured by Mitsui & Co., Ltd., and EMSI-Pack manufactured by Mitsubishi Chemical Engineering Co., Ltd. And grid type structured packing such as Flexigrid. In addition, gem packs manufactured by Dalitsu Co., Ltd., monppacks manufactured by Monk Co., Ltd., Goodronore Packing manufactured by Tokyo Special Wire Mesh Co., Ltd. Examples include impal packing.
• Examples of the irregular packing include Raschig ring, Pauling manufactured by BASF, Cascade mini ring manufactured by Mass Transfer Co., Ltd., IMTP manufactured by Norton Co., Ltd. Terralet manufactured by Nippon Steel Kakoki Co., Ltd .;
• the above-mentioned fillers may be used in combination of two or more. Also, it can be used in combination with the traditionally used trays.
• the operating conditions of the above-mentioned distillation column vary depending on the composition of the distillation raw material, the recovery rate, the purity of the distilled acrylic acid, and the like.
• acrylic acid is an easily polymerizable compound
• the distillation temperature and the pressure are set as low as possible and as low as possible.
• the bottom temperature is usually 60 to 100 ° C
• the top pressure is usually 127 kPa.
• a known polymerization inhibitor is added in order to suppress the generation of a polymer of (meth) acrylic acid or its ester.
• polymerization inhibitor examples include tertiary butyl nitroxide, 2,2,6,6-tetramethyl-4-hydroxypiberidyl-1-oxyl, 2,2,6,6-tetramethylpiberidyl-l-oxyl, 2,2,2 6,6-tetramethylpiperidinoxy, 4-hydroxy_2, 2,6,6-tetramethylpiperidinoxyl, 4, 4 ', 4''-tris 1_ (2, 2, 6, 6- N-oxyl compounds such as tetramethylpiperidinoxyl phosphite, phenol compounds such as hydroquinone, methoquinone, pyrogallol, catechol and resorcinol, phenothiazine, bis- (hi-methylbenzyl) phenothiazine, 3,7-dioctylphenothiazine, Phonothiazine compounds such as bis- (h-dimethylbenzyl) phenothiazine, cupric chloride, copper
• a nozzle or a pipe installed in the gas phase part of the above-mentioned handling device has a measuring device for monitoring the process state of (meth) atalylic acid or its ester, for example, pressure, temperature, liquid level and the like. Is installed. Examples of the measuring device include analyzers such as a pressure gauge, a liquid level gauge, a thermometer, an oxygen concentration meter, and a pH meter.
• Examples of the pressure gauge include a diaphragm pressure gauge, a bellows pressure gauge, and a Bourdon tube pressure gauge.
• Thermometers include thermocouple thermometers, resistance thermometers, and bimetallic thermometers.
• Examples of the liquid level gauge include a pressure level gauge, a differential pressure level gauge, and a gauge glass level gauge.
• the materials of the above-mentioned handling device body, nozzle, reboiler, condenser, vent gas capacitor, reflux tank, piping, pump as ancillary equipment, etc. should be a material that shows corrosion resistance under the compound being handled and its temperature conditions.
• a material that shows corrosion resistance under the compound being handled and its temperature conditions There is no particular limitation.
• the polymer that blocks the nozzles or pipes of the handling device is a polymer of (meth) acrylic acid or its ester derived from Michael adduct, (meth) acrylic acid or its ester And the like.
• Examples of the cauldron with Michael include (i) Michael adduct of acrylic acid, (ii) adduct of ester of acrylic acid, (m) Michael adduct of alcohol, and the like.
• acrylic acid dimer hereinafter abbreviated as “dimer”
• acrylic acid trimer hereinafter abbreviated as “trimer”
• acrylic acid 4 hereinafter abbreviated as “tetramer”
• ⁇ -hydroxypropionic acid and the like.
• the acrylate ester Michael adduct is a compound in which acrylic acid has been added to the above-mentioned acrylate ester such as an alkyl ester having 2 to 8 carbon atoms or a cycloalkyl ester. Include / 3-atthaloxypropionic acid such as methyl j3 _ataryloxypropionate, ethyl / 3_attaryloxypropionate, Esters and the like.
• the Michael adduct of alcohol is a compound in which alcohol or water is added to an acrylate, and specifically, an ester of j3_alkoxypropionate, dimer, trimer or tetramer, —hydroxypropionic acid And hydroxypropionates.
• the formed radical polymer is a copolymer of (meth) acrylic acid and (meth) acrylic ester.
• these radical polymerization product is (meth) acrylic acid or its ester polymer obtained by Michael addition sometimes force s are formed.
• the method for preventing clogging according to the present invention is characterized in that a gas having a polymerization inhibiting action is blown into a nozzle or a pipe connected to a gas phase part of a handling device under a condition not lower than the temperature of the gas phase part.
• FIG. 1 is a partial cross-sectional explanatory view showing an example of a state in which a gas injection port for preventing clogging is attached to a facility attached to a distillation apparatus.
• a measuring device (3) is attached to a column wall (11) constituting a gas phase portion of the distillation column (10) through a nozzle (2). It is provided.
• the nozzle (2) is provided with a gas blowing port (4), and a gas having a polymerization inhibiting action is blown into the nozzle (2) under conditions equal to or higher than the temperature of the gas phase.
• the gas having a polymerization inhibiting action is a gas containing oxygen gas and / or nitrogen oxide. Specifically, a mixed gas of an inert gas and nitrogen oxides and Z or air
• the inert gas examples include nitrogen, argon, carbon dioxide, steam and the like.
• the ratio (volume ratio) of the inert gas to oxygen and / or nitrogen oxide is usually 2 / 9896Z4.
• the temperature of the gas having the polymerization inhibiting action is equal to or higher than the temperature of the gas phase part, and is preferably a temperature higher by 030 ° C than the temperature of the gas phase part of the handling apparatus.
• condensation of (meth) acrylic acid or its ester occurs.
• the method of heating the gas having the polymerization inhibiting action is not particularly limited as long as a required temperature can be ensured.
• a method of heating with a heat exchanger generated during the process or outside the process Any method such as a mixing method of a heating gas is acceptable.
• Heat exchangers include a vertical fixed tube plate heat exchanger, a horizontal fixed tube plate heat exchanger, a U-tube heat exchanger, a double tube heat exchanger, a spiral heat exchanger, and a square block. Type heat exchanger, plate type heat exchanger and the like.
• the blowing rate of the gas having the polymerization inhibiting action is not particularly limited as long as the required temperature is maintained. Further, the diameter and the installation angle of the blowing nozzle are not particularly limited as long as the required temperature is maintained.
• Example 2 The same operation as in Example 1 was performed, except that the temperature of the air blown into the horn from the inlet was set to 24 ° C. (which was the outside temperature). Since the pressure indication of the pressure gauge gradually increased from two weeks after the start of operation, the operation start force was stopped after four weeks, and the nozzle was clogged with a polymer of atalylic acid. .
• Example 2 Using the same distillation apparatus as in Example 1, an ethyl acrylate solution containing 0.3% by weight of ethanol and 1.8% by weight of water was introduced at a rate of 6 tZh. By operating at a tower bottom temperature of 90 ° C., ethyl acetyl ester containing no ethanol and water was obtained from the bottom of the tower. Attach a pressure gauge to the 3 / 4-inch nozzle installed in the gas phase at the top and bottom of this distillation column. The nozzle installed at the top of the tower has a mixed gas (oxygen concentration) at a temperature of 78 ° C.
• a mixed gas oxygen concentration
• Example 2 The same operation as in Example 2 was performed, except that the temperature of the air blown from the air inlet into the horn was set to 24 ° C. (external temperature). After 3 weeks from the start of operation, the pressure indicator of the pressure gauge gradually increased. After 5 weeks from the start of operation, the operation was stopped and an inspection was performed. As a result, the nozzle was clogged with a polymer of ethyl acrylate.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2004
  • 2004-03-23 JP JP2004083954A patent/JP4412019B2/ja not_active Expired - Lifetime
  • 2004-08-09 WO PCT/JP2004/011445 patent/WO2005090277A1/ja not_active Ceased
  • 2004-08-09 CN CNB2004800003061A patent/CN100447122C/zh not_active Expired - Lifetime
  • 2004-11-16 TW TW093135143A patent/TW200531961A/zh unknown
  • 2004-12-01 US US11/000,505 patent/US7135594B2/en not_active Expired - Lifetime

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