JP3972375B2 - Method for preventing polymerization at shaft seal part of rotating device - Google Patents
Method for preventing polymerization at shaft seal part of rotating device Download PDFInfo
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- JP3972375B2 JP3972375B2 JP23853194A JP23853194A JP3972375B2 JP 3972375 B2 JP3972375 B2 JP 3972375B2 JP 23853194 A JP23853194 A JP 23853194A JP 23853194 A JP23853194 A JP 23853194A JP 3972375 B2 JP3972375 B2 JP 3972375B2
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Description
【０００１】
【産業上の利用分野】
本発明は、アクリル酸、メタクリル酸(以下(メタ)アクリル酸という)、(メタ)アクリル酸エステル等の重合性液体を取り扱う回転機器（キャンドモーターポンプを除く）（以下「回転機器」はキャンドモーターポンプを除く回転機器を意味する）の軸封部分における重合防止方法に関するものである。さらに具体的には、重合性液体を取り扱う回転機器の軸封部分の冷却液として、酸素及び酸素以外の重合防止剤を含有する当該重合性液体を使用して、回転機の軸封部分における重合を防止する、工業的に有利な重合性液体の取扱方法に関するものであり、こられの重合性液体を製造および取り扱う化学業界他で広く利用され得るものである。
【０００２】
【従来の技術】
重合性液体は、製造工程、貯蔵もしくは輸送中に、熱、光、その他の要因により重合し、しばしばトラブルが発生することが知られている。
それらのトラブルの発生防止、すなわち、重合性液体の重合防止方法としては、フェノチアジン等の芳香族アミン類やハイドロキノン及びその誘導体等のフェノール類化合物等の重合防止剤の添加や酸素含有ガスとの接触が有効であることが知られており、且つ広く採用されている方法である。
一方、重合性液体を取り扱う機器には、ポンプや攪拌機等の回転機器があり、これらの機器においては、その軸封部分の冷却や潤滑のために、取り扱われる液体そのものが冷却液（注入液ともいう）として使用されているが、冷却液として使用された重合性液体は、しばしば、モーターやベアリング等の発熱により重合して、軸封部分において回転を阻害し、ポンプの破損や操業の停止といった重大なトラブルを発生させてきた。
軸封部分における重合を防止するために、冷却液としてアルコールや水等の非重合液体を用いることは可能であるが、ポンプ等の軸封部分からの漏洩により、重合性液体の品質を低下させる恐れが多いので採用が困難な方法である。
したがって、重合性液体、特に減圧下の重合性液体を取り扱う機器において、ポンプや攪拌機等の回転機器の軸封部分の冷却や潤滑のために、取り扱われる重合性液体そのものを冷却液（注入液）とし、且つ、軸封部分において該重合性液体の重合を防止する方法が強く求められている。
【０００３】
【発明が解決しようとする課題】
重合性液体の重合防止方法としての、フェノチアジン等の芳香族アミン類やハイドロキノン及びその誘導体等のフェノール類化合物等の重合防止剤の添加や酸素含有ガスとの接触は有効であり、重合性液体の製造工程及び取り扱いの際に一般的にこれら重合防止剤は１０〜５００００ppm 使用され十分な効果をあげている。
しかしながら、重合性液体をを取り扱う機器において、ポンプや攪拌機等の回転機器の軸封部分の冷却や潤滑のために、当該重合性液体そのものを冷却液（注入液）としなければならない場合においては、単純に重合防止剤を添加又は増量しただけでは、該重合性液体の重合を完全には防止できず、しばしば、該重合性液体が重合して、軸封部分において回転を阻害し、ポンプの破損や操業の停止といった重大なトラブルを発生させてきている。
さらに、重合を完全に防止しようとして、重合防止剤を多量添加することは、重合性液体の製品価値を低下させることになるため、採用し難い方法である。
これらのトラブルは、特に重合性液体を減圧下に取り扱う際によりしばしば発生し、蒸留等の操作を困難にしている。
本発明者等は、以上の様な重合性液体を取り扱う際に、回転機器において発生する問題点を解消すべく種々検討したのである。
【０００４】
【課題を解決するための手段】
本発明者らは、前記問題点を解消するために鋭意検討を重ねた結果、本発明を完成するに至ったのである。
すなわち、本発明は、（メタ）アクリル酸またはそれらのエステルを取り扱う回転機器の軸封部分の冷却液として当該（メタ）アクリル酸またはそれらのエステルの一部を利用する形式の回転機器の使用に際して、当該（メタ）アクリル酸またはそれらのエステルを酸素含有雰囲気と接触させて得た液を前記冷却液として軸封部分に供給することを特徴とする回転機器の軸封部分における重合防止方法に関するものである。
【０００５】
以下に本発明をさらに詳しく説明する。
本発明は、前述のとおり、（メタ）アクリル酸またはそのエステルを取り扱う回転機器における軸封部分の重合防止に関するものである。
本発明において回転機器で取り扱われる重合性液体は、（メタ）アクリル酸またはそのエステルであり、その具体例を挙げれば、（メタ）アクリル酸、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸シクロヘキシル、（メタ）アクリル酸２−エチルヘキシル等である。
本発明における回転機器は、軸封部分の冷却液として当該回転機器が取り扱う液体を利用する形式のもので、具体的にはそういう形式のポンプ及び撹拌機等である。すなわち、撹拌対象または輸送対象等の液体の一部を回転機器の軸封部分に供給する構造を有するポンプ及び撹拌機等の回転機器である。それらは広く採用されており、具体的には、注液用ダブルパッキング、注液用ダブルグラウンド、メカニカルシールによるダブル封液と補助封液の併用型（ポンプ その設備設計・運転・保守：日本機械学会 水力学・水力機械部門委員会編、丸善株式会社出版）等が挙げられる。
本発明においては、回転機器が取り扱う（メタ）アクリル酸またはそのエステル（以下重合性液体という）の一部を酸素含有雰囲気と接触させて得た液を、回転機器の軸封部分に供給する。
回転機器で取り扱われる重合性液体のうちから軸封部分の冷却用に取り出された重合性液体を、酸素含有雰囲気と接触させる方法としては、例えば以下のような方法がある。重合性液体が減圧状態のものであれば、単に酸素雰囲気下で常圧に戻す方法が適用され、常圧状態の重合性液体であれば、重合性液体中に酸素を含有する気体を導入してバブリング（暴気）する方法が適用され、更には、重合性液体中の酸素濃度が飽和に達するまでの時間は非常に短いため、大気圧下で酸素を含有する気体の雰囲気の貯槽に重合性液体を一旦貯蔵するという様な簡単な方法も適用可能である。この様な処理により重合性液体中に酸素が容易に取り込まれ、当該重合性液体の重合がより効果的に防止されるものと判断される。
酸素を含有する気体としては、特に限定されるものではないが、引火店の低い重合性液体を取り扱う場合は、空気などの様な酸素濃度が高い気体は、爆発性混合ガス（爆鳴気）を形成し危険性が増大するので、取り扱う液によっては、酸素濃度を２１容量％（空気）以下に抑えることが好ましい。また、酸素濃度が３容量％より低い場合は、本発明の効果が得られ難いので、酸素濃度は３容量％以上にすることが好ましい。
回転機器で取り扱われる重合性液体には、通常重合防止のために一般的な重合防止剤すなわちフェノチアジン等の芳香族アミン類やハイドロキノン及びその誘導対等のフェノール類化合物等（以下これらを有機性重合防止剤という）が１０〜５００００ppm含まれており、本発明においては、かかる有機性重合防止剤と前述の酸素があいまって、軸封部分の冷却液の重合を防止する。
【０００６】
【作用】
本発明では、重合性液体を取り扱うポンプや攪拌機等の回転機器の軸封部分の冷却液として、酸素及び酸素以外の重合防止剤を含有する当該重合性液体を用いることにより、回転機器の軸封部分での該重合性液体の重合を防止し、ポンプの破損や操業の停止といったトラブルの発生を抑えることができるのである。
【０００７】
【実施例】
以下に、本発明について実施例および比較例を挙げて詳細に説明する。
実施例１
アクリル酸９５重量％（ハイドロキノンモノメチルエーテル２０００ppm 含有）含み、温度９０±３℃、圧力８０±３Ｔorrの精留塔塔底液加熱器の循環用ポンプとして、二重のメカニカルシールによる封液及び注入液を使用する軸封構造を持つボリュートポンプを使用し、注入液には空気雰囲気の大気圧下で貯蔵したアクリル酸を使用したところ、トラブルもなく、１年間問題なく運転ができた。
【０００８】
実施例２
アクリル酸メチル９５重量％（ハイドロキノンモノメチルエーテル１０００ppm 含有）含み、温度５５±２℃、圧力２８０±５Ｔorrの精留塔塔底液加熱器の循環用ポンプとして、二重のメカニカルシールによる封液及び注入液を使用する軸封構造を持つボリュートポンプを使用し、注入液には５容量％酸素を含む窒素ガス雰囲気の大気圧下で貯蔵したアクリル酸メチルを使用したところ、トラブルもなく、１年間問題なく運転ができた。
【０００９】
実施例３
圧力５０Ｔorrのアクリル酸2-エチルヘキシル（ハイドロキノンモノメチルエーテル５００ppm 含有）の送液用のポンプとして、二重のメカニカルシールによる封液及び注入液を使用する軸封構造を持つボリュートポンプを使用し、注入液には空気雰囲気の大気圧下で貯蔵したアクリル酸2-エチルヘキシルを使用したところ、３年間以上トラブルもなく、順調な運転ができた。
【００１０】
実施例４
アクリル酸９０重量％（ハイドロキノンモノメチルエーテル１０００ppm 含有）含み、温度３０±１０℃、大気圧下の製造工程中間品（粗アクリル酸）の貯蔵タンクの攪拌機として、二重のメカニカルシールによる封液及び注入液を使用する軸封構造を持つ攪拌機を使用し、注入液には空気雰囲気の大気圧下で貯蔵したアクリル酸を使用したところ、２年間以上トラブルもなく、順調な運転ができた。
【００１１】
比較例１
実施例１と同様の箇所に、同型のボリュートポンプを使用し、注入液としては、圧力８０Ｔorrの精留塔塔底液そのものを使用した所、数時間後にポンプ内の重合トラブルにより、運転を停止した。
【００１２】
比較例２
実施例２と同様の箇所に、同型のボリュートポンプを使用し、注入液としては、圧力２８０Ｔorrの精留塔塔底液そのものを使用した所、数時間後にポンプ内の重合トラブルにより、運転を停止した。
【００１３】
比較例３
実施例３と同様の箇所に、同型のボリュートポンプを使用し、注入液としては、圧力５０Ｔorrのアクリル酸2-エチルヘキシルそのものを使用した所、１週間後にポンプ内の重合トラブルにより、運転を停止した。
【００１４】
比較例４
実施例４と同様の箇所に、同型の攪拌機を使用し、注入液としては、実施例１で得られた圧力８０Ｔorrのアクリル酸を使用した所、２週間後に攪拌機内の重合トラブルにより、運転を停止した。
【００１５】
【発明の効果】
重合性液体を取り扱うポンプや攪拌機等の回転機器の軸封部分の冷却液として、酸素及び酸素以外の重合防止剤を含有する当該重合性液体を用いることにより、重合性液体の品質を低下させることなく、回転機器内での重合が防止され、ポンプの破損や操業の停止といったトラブルの発生を抑えることができ、重合性液体の製造および使用等において工業的に有利な取り扱い方法を提供できるものである。[0001]
[Industrial application fields]
The present invention relates to a rotating device (excluding a canned motor pump) that handles a polymerizable liquid such as acrylic acid, methacrylic acid (hereinafter referred to as (meth) acrylic acid), (meth) acrylic acid ester, etc. It means a method for preventing polymerization in a shaft seal portion of a rotating device excluding a pump . More specifically, using the polymerizable liquid containing oxygen and a polymerization inhibitor other than oxygen as a cooling liquid for the shaft seal portion of a rotating device that handles the polymerizable liquid, polymerization in the shaft seal portion of the rotating machine is performed. The present invention relates to an industrially advantageous method for handling polymerizable liquids, which can be widely used in the chemical industry for manufacturing and handling these polymerizable liquids.
[0002]
[Prior art]
It is known that polymerizable liquids are polymerized due to heat, light, and other factors during the manufacturing process, storage or transportation, and trouble often occurs.
Prevention of such troubles, that is, as a method for preventing polymerization of the polymerizable liquid, addition of a polymerization inhibitor such as aromatic amines such as phenothiazine and phenolic compounds such as hydroquinone and derivatives thereof, and contact with oxygen-containing gas Is known to be effective and is a widely adopted method.
On the other hand, devices that handle polymerizable liquids include rotating devices such as pumps and agitators. In these devices, the liquid to be handled itself is a cooling liquid (both injection liquid and liquid) for cooling and lubrication of the shaft seal portion. However, the polymerizable liquid used as the coolant often polymerizes due to heat generated by the motor, bearings, etc., hindering rotation at the shaft seal, and causing damage to the pump or stoppage of operation. Serious trouble has occurred.
In order to prevent polymerization in the shaft seal part, it is possible to use a non-polymerized liquid such as alcohol or water as a cooling liquid, but the quality of the polymerizable liquid deteriorates due to leakage from the shaft seal part such as a pump. This method is difficult to adopt because there are many fears.
Therefore, in devices that handle polymerizable liquids, especially polymerizable liquids under reduced pressure, the treated polymerizable liquid itself is used as a cooling liquid (injection solution) for cooling and lubrication of shaft seals of rotating devices such as pumps and agitators. In addition, there is a strong demand for a method for preventing polymerization of the polymerizable liquid at the shaft seal portion.
[0003]
[Problems to be solved by the invention]
As a method for preventing polymerization of a polymerizable liquid, addition of a polymerization inhibitor such as aromatic amines such as phenothiazine and phenol compounds such as hydroquinone and its derivatives and contact with an oxygen-containing gas are effective. In the production process and handling, these polymerization inhibitors are generally used in an amount of 10 to 50000 ppm, which is sufficiently effective.
However, in a device that handles a polymerizable liquid, in order to cool or lubricate a shaft seal portion of a rotary device such as a pump or a stirrer, the polymerizable liquid itself must be used as a cooling liquid (injected liquid). Simply adding or increasing the polymerization inhibitor does not completely prevent the polymerization of the polymerizable liquid, and often the polymerizable liquid polymerizes, hinders rotation at the shaft seal portion, and breaks the pump. And serious troubles such as suspension of operations.
Furthermore, adding a large amount of a polymerization inhibitor in an attempt to completely prevent polymerization is a method that is difficult to employ because it reduces the product value of the polymerizable liquid.
These troubles often occur especially when the polymerizable liquid is handled under reduced pressure, making operations such as distillation difficult.
The present inventors have made various studies to solve the problems that occur in rotating equipment when handling the polymerizable liquid as described above.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the present invention uses a rotating device of a type that utilizes a part of the (meth) acrylic acid or their ester as a coolant for the shaft seal portion of the rotating device that handles (meth) acrylic acid or their esters. A method for preventing polymerization in a shaft seal portion of a rotating device, characterized in that a liquid obtained by contacting the (meth) acrylic acid or an ester thereof with an oxygen-containing atmosphere is supplied to the shaft seal portion as the cooling liquid. It is.
[0005]
The present invention is described in further detail below.
As described above, the present invention relates to prevention of polymerization of a shaft seal portion in a rotating machine that handles (meth) acrylic acid or its ester.
The polymerizable liquid to be handled by the rotating equipment have you in the present invention, (meth) acrylic acid or an ester thereof, by way of specific examples, (meth) acrylic acid, (meth) acrylate, (meth) acrylic Examples thereof include ethyl acetate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , and the like .
The rotating device in the present invention is of a type that uses the liquid handled by the rotating device as the coolant of the shaft seal portion, and specifically, is a pump and a stirrer of such a type . That is, it is a rotary device such as a pump and a stirrer having a structure for supplying a part of a liquid to be stirred or transported to a shaft seal portion of the rotary device. They are widely adopted. Specifically, double packing for liquid injection, double ground for liquid injection, and double sealing with mechanical seal and auxiliary sealing liquid (pump, equipment design, operation and maintenance: Nippon Machinery) Society of hydraulics, hydraulic machinery department committee, ed., Ru include Maruzen Co., Ltd. publication), and the like.
In the present invention, a liquid obtained by bringing a part of (meth) acrylic acid or its ester (hereinafter referred to as a polymerizable liquid) handled by the rotating device into contact with an oxygen-containing atmosphere is supplied to the shaft seal portion of the rotating device .
Examples of the method for bringing the polymerizable liquid taken out for cooling the shaft seal portion out of the polymerizable liquid handled by the rotating device into contact with the oxygen-containing atmosphere include the following methods. If the polymerizable liquid is in a reduced pressure state, a method of simply returning to atmospheric pressure in an oxygen atmosphere is applied. If the polymerizable liquid is in an atmospheric pressure state, a gas containing oxygen is introduced into the polymerizable liquid. In addition, since the time until the oxygen concentration in the polymerizable liquid reaches saturation is very short, polymerization is performed in a gas atmosphere containing oxygen at atmospheric pressure. A simple method such as storing the liquid once is also applicable. By such treatment, it is judged that oxygen is easily taken into the polymerizable liquid and the polymerization of the polymerizable liquid is more effectively prevented.
The oxygen-containing gas is not particularly limited, but when handling a polymerizable liquid with a low flash point, a gas with a high oxygen concentration such as air is an explosive gas mixture (explosive gas). Therefore, depending on the liquid to be handled, it is preferable to suppress the oxygen concentration to 21% by volume (air) or less. Further, when the oxygen concentration is lower than 3% by volume, it is difficult to obtain the effects of the present invention. Therefore, the oxygen concentration is preferably 3% by volume or more.
A polymerizable liquid to be handled by the rotating device, the general polymerization inhibitor for normal polymerization prevention i.e. aromatic amines such as phenothiazine and hydroquinone and phenol compounds of the induction peer (hereinafter prevent these organic polymer In the present invention, the organic polymerization inhibitor and the oxygen described above are combined to prevent polymerization of the coolant in the shaft seal portion.
[0006]
[Action]
In the present invention, a shaft seal of a rotating device is used by using the polymerizable liquid containing oxygen and a polymerization inhibitor other than oxygen as a coolant for a shaft seal portion of a rotating device such as a pump or a stirrer that handles the polymerizable liquid. It is possible to prevent the polymerization liquid from being polymerized in the portion, and to suppress the occurrence of troubles such as breakage of the pump and stop of operation.
[0007]
【Example】
Below, an Example and a comparative example are given and this invention is demonstrated in detail.
Example 1
Sealing and injection liquid with double mechanical seal as circulating pump for rectifying tower bottom liquid heater with acrylic acid 95wt% (containing hydroquinone monomethyl ether 2000ppm), temperature 90 ± 3 ° C, pressure 80 ± 3Torr Using a volute pump with a shaft seal structure using Acrylic acid and acrylic acid stored under atmospheric pressure in an air atmosphere was used as the injection solution.
[0008]
Example 2
Sealing and injection with double mechanical seal as circulating pump for rectification tower bottom liquid heater with 95wt% methyl acrylate (containing 1000ppm hydroquinone monomethyl ether), temperature 55 ± 2 ° C, pressure 280 ± 5Torr Using a volute pump with a shaft seal structure that uses liquid, and using methyl acrylate stored under atmospheric pressure in a nitrogen gas atmosphere containing 5% oxygen as the injection solution, there is no problem for one year. I was able to drive without.
[0009]
Example 3
As a pump for feeding 2-ethylhexyl acrylate (containing 500 ppm of hydroquinone monomethyl ether) at a pressure of 50 Torr, a volute pump with a double-sealing seal and a shaft seal structure that uses an injection solution is used. When using 2-ethylhexyl acrylate stored under atmospheric pressure in an air atmosphere, it was possible to operate smoothly without trouble for more than 3 years.
[0010]
Example 4
Sealing and injection with double mechanical seal as a stirrer for storage tank of intermediate product (crude acrylic acid) at 30 ± 10 ° C, atmospheric pressure, containing 90 wt% acrylic acid (containing 1000 ppm hydroquinone monomethyl ether) When a stirrer having a shaft seal structure using a liquid was used and acrylic acid stored under atmospheric pressure in an air atmosphere was used as the injection liquid, there was no trouble for more than two years and a smooth operation was possible.
[0011]
Comparative Example 1
A volute pump of the same type was used at the same location as in Example 1, and the operation was stopped due to polymerization trouble in the pump after several hours when the rectifying tower bottom liquid itself at a pressure of 80 Torr was used as the injection liquid. did.
[0012]
Comparative Example 2
A volute pump of the same type was used at the same location as in Example 2, and the operation was stopped due to polymerization problems in the pump after several hours when the rectifying tower bottom liquid itself at a pressure of 280 Torr was used as the injection liquid. did.
[0013]
Comparative Example 3
A volute pump of the same type was used in the same place as in Example 3, and 2-ethylhexyl acrylate itself with a pressure of 50 Torr was used as the injection solution, and the operation was stopped after 1 week due to polymerization trouble in the pump. .
[0014]
Comparative Example 4
The same type of stirrer was used in the same place as in Example 4, and acrylic acid with a pressure of 80 Torr obtained in Example 1 was used as the injection liquid. After 2 weeks, the operation was caused by polymerization trouble in the stirrer. Stopped.
[0015]
【The invention's effect】
Decreasing the quality of the polymerizable liquid by using the polymerizable liquid containing oxygen and a polymerization inhibitor other than oxygen as the cooling liquid of the shaft seal portion of a rotating device such as a pump or a stirrer that handles the polymerizable liquid. In addition, polymerization in the rotating equipment is prevented, troubles such as pump breakage and operation stoppage can be suppressed, and an industrially advantageous handling method can be provided in the production and use of polymerizable liquids. is there.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23853194A JP3972375B2 (en) | 1994-09-06 | 1994-09-06 | Method for preventing polymerization at shaft seal part of rotating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23853194A JP3972375B2 (en) | 1994-09-06 | 1994-09-06 | Method for preventing polymerization at shaft seal part of rotating device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0875012A JPH0875012A (en) | 1996-03-19 |
| JP3972375B2 true JP3972375B2 (en) | 2007-09-05 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23853194A Expired - Lifetime JP3972375B2 (en) | 1994-09-06 | 1994-09-06 | Method for preventing polymerization at shaft seal part of rotating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3972375B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100370167C (en) | 2001-11-22 | 2008-02-20 | 三菱化学株式会社 | Method and device for feeding polymerization liquid |
| DE10228859A1 (en) * | 2002-06-27 | 2004-01-15 | Basf Ag | Method for conveying a liquid F containing at least one (meth) acrylic monomer |
| JP5155372B2 (en) * | 2010-10-21 | 2013-03-06 | 住友化学株式会社 | Polymerization reaction apparatus and polymer production method using the same |
-
1994
- 1994-09-06 JP JP23853194A patent/JP3972375B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| JPH0875012A (en) | 1996-03-19 |
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