JP2006193689A - Method for coating scale adhesion preventing agent - Google Patents
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Abstract
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本発明は、重合反応器内壁へのスケール付着防止剤の塗布方法に関するものである。 The present invention relates to a method for applying a scale adhesion preventing agent to the inner wall of a polymerization reactor.
従来、オレフィン系単量体の重合方法としては、懸濁重合法、乳化重合法、溶液重合法、気相重合法、塊状重合法等が知られているが、これらの重合法においては、いずれの場合にも、重合反応器内部表面に重合体スケールの付着が生起し易い。
重合体スケールが重合反応器内部表面に付着すると、重合体の収率、重合反応器冷却能力等が低下するばかりでなく、この重合体スケールが剥離して重合体中に混入する結果、重合体から得られる生成物の品位が低下する問題が発生する。
そのため、重合反応器内部に付着した重合体スケールを除去することが必要になるが、この除去方法としては、重合反応器に人が入って付着物を取り除くか又は重合反応器のマンホールを開放し、高圧水ジェット洗浄装置を使用して付着した重合物にジェット水流を当てて取り除く方法等が考えられる。
しかし、これらの除去方法については、過大な労力と時間を要するのみならず、この重合体スケール中には未反応の単量体が含まれているため人体障害の危険性があるから、スケール除去作業を如何に少なくするかが重要な課題となっている。
Conventionally, suspension polymerization methods, emulsion polymerization methods, solution polymerization methods, gas phase polymerization methods, bulk polymerization methods, and the like are known as polymerization methods for olefinic monomers. Also in this case, adhesion of the polymer scale tends to occur on the inner surface of the polymerization reactor.
When the polymer scale adheres to the inner surface of the polymerization reactor, not only the yield of the polymer, the cooling capacity of the polymerization reactor, etc., but also the polymer scale peels off and is mixed into the polymer. There arises a problem that the quality of the product obtained from the above is lowered.
Therefore, it is necessary to remove the polymer scale adhering to the inside of the polymerization reactor. As this removal method, a person enters the polymerization reactor to remove the adhering matter, or the manhole of the polymerization reactor is opened. For example, a method of applying a jet water stream to the polymer adhered using a high-pressure water jet cleaning apparatus and removing the polymer can be considered.
However, these removal methods require not only excessive labor and time, but also the scale removal because there is a risk of human injury because the polymer scale contains unreacted monomers. How to reduce the work is an important issue.
このため、従来から、重合反応器内部表面の重合体スケールの付着を防止する方法として、重合体スケール付着防止剤の皮膜を重合反応器内部表面に形成する方法が知られている。
例えば、重合反応器内上部に設けた液体−気体の流体噴霧ノズルより、単量体もしくは重合体が接触する器壁、管壁、その他の装置部表面に、あらかじめスケール付着防止剤を噴霧してスケール付着防止塗膜を形成した後、このノズルより注水しながら重合を行うことを特徴とする重合反応器内壁等へのスケール付着防止法（特許文献１）、フイルムの形でポリマービルドアップを防止することのできるコーティング物質のコーティング溶液を作成すること、上記コーティング物質のためのキャリアーとして作用する塩化ビニルのガスの上記コーティング溶液に対する作用によって重合反応器の表面に上記コーティング物質を適用すること、及びついで上記重合反応器のコーティングされた内部表面と常に接触させながらモノマーの重合を行うことを含む、重合反応器の内部表面上のポリマービルドアップを実質的に排除する方法（特許文献２）、等がある。
For this reason, conventionally, as a method for preventing the adhesion of the polymer scale on the inner surface of the polymerization reactor, a method of forming a film of the polymer scale adhesion preventing agent on the inner surface of the polymerization reactor is known.
For example, an anti-scale adhesion agent is sprayed in advance on the vessel wall, tube wall, or other device surface that comes into contact with the monomer or polymer from a liquid-gas fluid spray nozzle provided in the upper part of the polymerization reactor. After forming a scale adhesion prevention coating film, polymerization is performed while pouring water from this nozzle. A method for preventing adhesion of scale to the inner wall of the polymerization reactor (Patent Document 1), preventing polymer build-up in the form of a film Creating a coating solution of the coating material that can be applied, applying the coating material to the surface of the polymerization reactor by the action of a gas of vinyl chloride acting as a carrier for the coating material on the coating solution; and The monomer is then polymerized in constant contact with the coated internal surface of the polymerization reactor. Comprising substantially way to eliminate polymer buildup on the internal surfaces of the polymerization reactor (Patent Document 2), and the like.
しかし、上述した従来方法のように、スプレー方式でスケール付着防止剤の塗布を行う方法では、例えば容積が８０ｍ３以上の大型重合反応器の内壁面にスケール付着防止剤皮膜を均一に形成することが困難である。即ち、スケール付着防止剤を噴霧するためのスプレーノズルは、一般的に重合反応器上部に設置されるが、重合反応器が大型になるほど、該ノズルと重合反応器の底部との距離が長くなるため、スケール付着防止剤塗布液の液滴を十分な量だけ重合反応器底部に運ぶことが難しく、この結果として、スケール付着防止剤皮膜を重合反応器内壁に均一に形成することが困難となっているのである。
このような傾向は、閉鎖された重合系において一層顕著である。例えば、閉鎖されている重合反応器内で、スプレーノズルを用いて噴霧を行った場合、重合反応器の下部に器内ガスの滞留を生じ、重合反応器下部までのガスの流れが生じにくくなる。このために、重合反応器内壁面の下部に十分な量のスケール付着防止剤を塗布することが一層困難となっており、これらの部分へのスケール付着の発生を有効に防止することが出来ないという欠点があった。
そこで、このような欠点を解消するための方法として、閉鎖された重合反応器の上部からスケール付着防止剤を含有する塗布液を噴霧すると同時に、重合反応器底部より器内ガスの吸引を行い、余剰の塗布液を排出して重合反応器内壁にスケール付着防止剤皮膜を生成する方法（特許文献３）が開発されている。
However, in the method of applying the scale adhesion inhibitor by the spray method as in the conventional method described above, for example, a scale adhesion inhibitor film is uniformly formed on the inner wall surface of a large polymerization reactor having a volume of 80 m 3 or more. Is difficult. That is, the spray nozzle for spraying the scale adhesion preventing agent is generally installed at the top of the polymerization reactor, but the larger the polymerization reactor, the longer the distance between the nozzle and the bottom of the polymerization reactor. For this reason, it is difficult to carry a sufficient amount of droplets of the scale adhesion inhibitor coating liquid to the bottom of the polymerization reactor, and as a result, it becomes difficult to uniformly form a scale adhesion inhibitor film on the inner wall of the polymerization reactor. -ing
Such a tendency is more remarkable in a closed polymerization system. For example, when spraying is performed using a spray nozzle in a closed polymerization reactor, the gas in the reactor stays in the lower part of the polymerization reactor, and the gas flow to the lower part of the polymerization reactor is less likely to occur. . For this reason, it has become more difficult to apply a sufficient amount of scale adhesion preventing agent to the lower part of the inner wall surface of the polymerization reactor, and it is impossible to effectively prevent the occurrence of scale adhesion on these parts. There was a drawback.
Therefore, as a method for solving such drawbacks, the coating liquid containing the scale adhesion preventing agent is sprayed from the top of the closed polymerization reactor, and at the same time, the gas in the chamber is sucked from the bottom of the polymerization reactor, A method (Patent Document 3) has been developed in which excess coating liquid is discharged to produce a scale adhesion inhibitor film on the inner wall of the polymerization reactor.
しかしながら、上記の方法は、重合反応器底部より器内ガスの吸引を行いながら、スケール付着防止剤皮膜を形成する方法であるので、どうしてもスケール付着防止剤が排出ガスに同伴して排出されるため、スケール付着防止剤の無駄が避けられない点で、十分なものとはいえない。
そして、近年のスケール付着防止剤の性能向上には目を見張るものがあるが、その塗布方法については問題がある。即ち、精々１００バッチ良くて３００バッチの繰返し重合後には、反応器に人が入って付着物を取り除くか、又は重合反応器のマンホールを開放して、高圧水ジェット洗浄装置により、付着した重合物を除去する等の作業をしなくてはならない。
従って、長期間の連続運転、例えば、一年間以上あるいは１０００バッチ以上の重合後であっても、付着による生産停止の必要のない、重合反応器内部表面のスケール付着防止技術の開発が待たれている。
特に、塩化ビニル系モノマーの重合の場合、塩化ビニルモノマーは有害であり、大気中に放出される量を削減する取り組みがなされているだけに、上記の課題は重要なテーマである。
However, since the above method is a method of forming a scale adhesion inhibitor film while sucking the gas from the bottom of the polymerization reactor, the scale adhesion inhibitor is inevitably discharged with the exhaust gas. However, it cannot be said that the waste of the scale adhesion preventing agent is unavoidable.
And although there is a remarkable improvement in the performance of scale adhesion inhibitors in recent years, there is a problem with the application method. That is, after repeated polymerization of 100 batches at best and 300 batches, a person enters the reactor to remove the deposits, or the manhole of the polymerization reactor is opened and the deposited polymer is removed by a high-pressure water jet cleaning device. It is necessary to do the work such as removing.
Therefore, development of a technique for preventing the adhesion of scale on the inner surface of the polymerization reactor is awaited, which does not require production stoppage due to adhesion even after long-term continuous operation, for example, after polymerization for one year or more or 1000 batches or more. Yes.
In particular, in the case of polymerization of vinyl chloride monomers, vinyl chloride monomers are harmful, and the above problem is an important theme because efforts are being made to reduce the amount released into the atmosphere.
本発明の課題は、オレフィン系単量体、特に、塩化ビニルの重合において、長期間の連続運転を可能にする、重合反応器内部表面のスケール付着防止剤の塗布方法を提供することにある。 An object of the present invention is to provide a coating method of a scale adhesion preventing agent on the inner surface of a polymerization reactor, which enables continuous operation for a long period in polymerization of an olefin monomer, particularly vinyl chloride.
本発明者らは、上記の課題を解決するため鋭意研究を重ねたところ、オレフィン系単量体、特に、塩化ビニルの重合反応器内部表面にスケール付着防止剤の皮膜を形成する場合、単にスケール付着防止剤を散布したのでは、スケール付着防止剤が器内全体に十分に行き渡らないが、該スケール付着防止剤を噴霧して、２つのガス流（上昇流と下降流）を生起させ、スケール付着防止剤を器内で循環させれば、該反応器内部表面にスケール付着防止剤の皮膜を均一に形成し得ることを知り、更に研究を重ねた結果、本発明を完成するに至った。 The inventors of the present invention have made extensive studies in order to solve the above-mentioned problems. As a result, when a film of a scale adhesion inhibitor is formed on the inner surface of a polymerization reactor of an olefin monomer, particularly vinyl chloride, the scale is simply When the anti-adhesive agent is sprayed, the scale anti-adhesive agent does not spread throughout the entire vessel, but the scale anti-adhesive agent is sprayed to generate two gas flows (upflow and downflow), and the scale As a result of further research, it has been completed that the present invention has been completed.
本発明は、以下の発明から構成されるものである。
１ 重合反応器内にスケール付着防止剤を攪拌下に噴霧し、該重合反応器内壁に沿って上昇流を、また重合反応器中心部に下降流を生起させることにより、重合反応器内でスケール付着防止剤を循環させ、重合反応器内部表面にスケール付着防止剤を塗布することを特徴とするスケール付着防止剤の塗布方法。
２ 攪拌が、重合反応器の撹拌機により行うものである上記１記載のスケール付着防止剤の塗布方法。
３ 重合反応器の内部表面近傍におけるスケール付着防止剤の流れを、鉛直方向の上昇流と水平方向の水平流に分解したとき、上昇流および水平流がそれぞれ下記式（１）及び（２）を満足するものである上記１又は２記載のスケール付着防止剤の塗布方法。
上昇流 １≦ｕｖ×ｔｖ／Ｌｖ≦８０ （１）
水平流 ３≦ｕH ×ｔH ／ＬH ≦２４０ （２）
ただし、上記式中、
ｕｖ：上昇流の平均流速（０．３〜２ｍ／秒）
ｔｖ：上昇流を与える時間（秒）
Ｌｖ：重合反応器をその鉛直軸を通る鉛直平面で切断したときの断面内周（ｍ）
ｕH：水平流の平均流速（０．８〜５ｍ／秒）
ｔH：水平流を与える時間（秒）
ＬH：重合反応器を水平平面で切断したときの断面内周（ｍ）
４ 重合反応器内の気体重量に占めるスケール付着防止剤の重量が０．０５〜０．１５％である上記１、２又は３記載のスケール付着防止剤の塗布方法。
なお、本発明にいう重合反応器断面内周は、重合反応器の縦、横、高さ等の寸法から算出される値であり、該重合反応器の内壁や付属装置（バッフル、バッフルサポート、撹拌翼、撹拌翼軸、温度計、レベル計、内装配管等）によって形成される凹凸を無視したものである。例えば、重合反応器が上下に半球状の蓋部（鏡部という）を有する円筒形状の場合には、重合反応器断面内周は以下の方法により求めることができる。
（１）重合反応器 鉛直断面内周（Ｌｖ）
Ｌｖ＝Ｈ＋Ｌ＋２／４×ｃ
Ｈ：重合反応器 高さ
Ｌ：重合反応器 直胴長さ
ｃ：重合反応器 鏡部１：２楕円周長さ
ｃ＝２×π×√｛（ａ２＋ｂ２）÷２｝
（ａ：楕円長軸長さ、ｂ:短軸長さ）
（２）重合反応器 水平断面内周（Ｌｈ）
Ｌｈ＝π×Ｄ
Ｄ：重合反応器 直径
The present invention comprises the following inventions.
1. A scale adhesion inhibitor is sprayed into the polymerization reactor under agitation, and an upward flow is generated along the inner wall of the polymerization reactor and a downward flow is generated in the central portion of the polymerization reactor. A method for applying a scale adhesion preventing agent, comprising circulating an adhesion prevention agent and applying the scale adhesion preventing agent to the inner surface of the polymerization reactor.
2. The coating method of the scale adhesion preventing agent according to 1 above, wherein the stirring is performed with a stirrer of a polymerization reactor.
3 When the flow of the scale adhesion preventing agent in the vicinity of the inner surface of the polymerization reactor is decomposed into a vertical upward flow and a horizontal horizontal flow, the upward flow and horizontal flow are expressed by the following equations (1) and (2), respectively. 3. The coating method of the scale adhesion preventing agent according to 1 or 2, which is satisfactory.
Upflow 1 ≦ u v × t v / L v ≦ 80 (1)
Horizontal flow 3 ≦ u H × t H / L H ≦ 240 (2)
However, in the above formula,
u v : Average flow velocity of upflow (0.3-2 m / sec)
tv : Time (seconds) to give upward flow
L v : inner circumference (m) when the polymerization reactor is cut along a vertical plane passing through its vertical axis
u H : Average flow velocity of horizontal flow (0.8 to 5 m / sec)
t H : Time for giving horizontal flow (seconds)
L H : Inner circumference of the cross section when the polymerization reactor is cut in a horizontal plane (m)
4. The method for applying a scale adhesion preventing agent according to the above 1, 2 or 3, wherein the weight of the scale adhesion inhibiting agent in the gas weight in the polymerization reactor is 0.05 to 0.15%.
The inner circumference of the cross section of the polymerization reactor referred to in the present invention is a value calculated from dimensions such as the vertical, horizontal, and height of the polymerization reactor, and the inner wall of the polymerization reactor and attached devices (baffle, baffle support, The unevenness formed by the stirring blade, the stirring blade shaft, the thermometer, the level meter, the interior piping, etc.) is ignored. For example, when the polymerization reactor has a cylindrical shape having hemispherical lid parts (referred to as mirror parts) above and below, the inner circumference of the polymerization reactor cross section can be obtained by the following method.
(1) Polymerization reactor Vertical section inner circumference (Lv)
Lv = H + L + 2/4 × c
H: Polymerization reactor height
L: polymerization reactor straight body length
c: Polymerization reactor, mirror part 1: 2 elliptical circumference
c = 2 × π × √ {(a 2 + b 2 ) / 2}
(A: ellipse major axis length, b: minor axis length)
(2) Polymerization reactor Horizontal section inner circumference (Lh)
Lh = π × D
D: Diameter of polymerization reactor
本発明の重合反応器内部表面のスケール付着防止方法は、重合反応器の上部からスケール付着防止剤を撹拌下に噴霧させて、該反応器内壁に沿ってガス上昇流を、反応器中心部にガス下降流を、それぞれ生起させることにより、重合反応器内でスケール付着防止剤を循環させ、重合反応器内部表面にスケール付着防止剤を塗布することを特徴とするものである。
本発明によれば、重合反応器内壁や付属装置等の表面をスケール付着防止剤で均一に被覆し得るため、長時間の連続運転が可能となり、その効果は大である。
In the method for preventing scale adhesion on the inner surface of the polymerization reactor of the present invention, a scale adhesion preventing agent is sprayed from the upper part of the polymerization reactor under stirring, and a gas upward flow along the inner wall of the reactor is caused to flow into the center of the reactor. Each of the gas descending flows is caused to circulate the scale adhesion preventing agent in the polymerization reactor, and the scale adhesion preventing agent is applied to the inner surface of the polymerization reactor.
According to the present invention, the inner wall of the polymerization reactor, the surface of the attached device and the like can be uniformly coated with the scale adhesion preventing agent, so that continuous operation for a long time is possible, and the effect is great.
本発明は、以下の知見に基づいてなされたものである。
（１）重合反応器内部表面にスケール付着防止剤を塗布する場合、単にスケール付着防止剤を散布したのでは、該反応器内部に装入するスケール付着防止剤含有液の初速度だけでは、該スケール付着防止剤が全体に充分行き渡らないので、スケール付着防止剤を均一に塗布することはできない。
（２）そこで、スケール付着防止剤を装置内に上昇または下降するガス流として、均一散布しようとすることも考えられるが、その場合、スケール付着防止剤散布の所要時間を長くするか又はスケール付着防止剤を多量に使用する必要が出てくる。
（３）ところが、重合反応器内にスケール付着防止剤を攪拌下に噴霧させて、２つのガス流、即ち、重合反応器内壁に沿ってガス上昇流を、重合反応器の中心部にガス下降流をそれぞれ生起させて、スケール付着防止剤を重合反応器内で循環すれば、該ガス流に同伴したスケール付着防止剤が、短時間に均一に、重合反応器内部表面に塗布されることをつきとめた。
上記の撹拌手段としては、重合反応器に付属設置された撹拌機を使用することが本発明において好ましい実施態様である。
The present invention has been made based on the following findings.
(1) When applying an anti-scale adhesion agent to the polymerization reactor internal surface, simply spraying the anti-scale adhesion agent, the initial rate of the scale anti-oxidation agent-containing liquid charged into the reactor alone, Since the scale adhesion preventive agent does not spread over the whole, the scale adhesion preventive agent cannot be applied uniformly.
(2) Therefore, it is conceivable to uniformly spray the scale adhesion inhibitor as a gas flow rising or descending into the apparatus. In this case, the time required for spraying the scale adhesion inhibitor is increased or the scale adhesion is performed. It becomes necessary to use a large amount of inhibitor.
(3) However, the scale adhesion inhibitor is sprayed into the polymerization reactor under stirring, and two gas flows, that is, a gas rising flow along the inner wall of the polymerization reactor, and a gas descending to the center of the polymerization reactor. If the scale adhesion inhibitor is circulated in the polymerization reactor by generating each flow, the scale adhesion inhibitor accompanying the gas stream is uniformly applied to the inner surface of the polymerization reactor in a short time. I caught it.
As the above stirring means, it is a preferred embodiment in the present invention to use a stirrer attached to the polymerization reactor.
このように、本発明では、重合反応器内部表面に、スケール付着防止剤を効率的に均一に塗布することができるが、その理由は、以下の通りである。
（１）撹拌翼による重合反応器内のガス流動は、元来、塩化ビニル系樹脂製造に適した撹拌条件（構造物による撹拌流動をも考慮した流動解析の結果が撹拌翼、バッフル等の諸条件を加味して設計されたもの）を設定したものであることから、流体が液からガスに変わっても反応器内の隅々まで、反応機内をガスが循環すると考えられる。
（２）２つのガス流（上昇流と下降流）が自然に形成されるのは、上昇流と下降流との間に仮想境界が形成されるためであると推察される。
何れにしても、本発明の特徴は、重合反応器内に霧状（平均粒径１０〜２００μｍと推定される）のスケール付着防止剤を撹拌下装入して、反応器内に上昇するガス流及び下降するガス流を作ることにより、スケール付着防止剤を重合反応器内で循環させて、重合反応器内部表面にスケール付着防止剤を均一に塗布した点にあり、そのための手段として、重合反応器に付設した撹拌翼をそのまま利用できる点において、簡便であり、経済的であるとともに、本発明によれば、長時間の連続運転が可能となる。
As described above, in the present invention, the scale adhesion preventing agent can be efficiently and uniformly applied to the inner surface of the polymerization reactor. The reason is as follows.
(1) The gas flow in the polymerization reactor by the stirring blades is essentially the same as the stirring conditions suitable for the production of vinyl chloride resin (the results of the flow analysis taking into account the stirring flow by the structure) Therefore, even if the fluid changes from liquid to gas, it is considered that the gas circulates in the reactor to every corner of the reactor.
(2) The reason why two gas flows (upflow and downflow) are naturally formed is presumed to be because a virtual boundary is formed between the upflow and the downflow.
In any case, the feature of the present invention is that the mist-like (average particle size estimated to be 10 to 200 μm) scale adhesion preventive agent is charged into the polymerization reactor under stirring, and the gas rising into the reactor. The scale adhesion inhibitor is circulated in the polymerization reactor by creating a flow and a descending gas stream, and the scale adhesion inhibitor is uniformly applied to the inner surface of the polymerization reactor. It is simple and economical in that the stirring blade attached to the reactor can be used as it is, and according to the present invention, continuous operation for a long time is possible.
以下、本発明をさらに詳細に説明する。
本発明の重合反応器内部表面のスケール付着防止方法は、重合反応器の上部からスケール付着防止剤を攪拌下に噴霧し、該重合反応器内壁に沿って上昇流を、重合反応器中心部に下降流を生起させることにより、重合反応器内でスケール付着防止剤を循環させ、重合反応器内部表面にスケール付着防止剤を均一に塗布することを特徴とするものである。
Hereinafter, the present invention will be described in more detail.
In the method for preventing scale adhesion on the inner surface of the polymerization reactor of the present invention, a scale adhesion inhibitor is sprayed from the upper part of the polymerization reactor under stirring, and the upward flow is directed along the inner wall of the polymerization reactor to the center of the polymerization reactor. By causing a downward flow, the scale adhesion preventing agent is circulated in the polymerization reactor, and the scale adhesion preventing agent is uniformly applied to the inner surface of the polymerization reactor.
そこで、上記の本発明の構成要件について、説明する。
（１）スケール付着防止剤
スケール付着防止剤は、通常のものが使用し得る。
スケール付着防止剤としては、例えば、ポリアミノベンゼン、多価フェノール、アミノフェノール、アルキル置換アミノフェノール、ジフェニルアミン又はアルキル置換ジフェノールアミンから選ばれた一種又は二種以上の化合物の縮合反応によって得られる他、芳香族アミン；レゾルシン、ヒドロキノン、カテコール又はフロログロシン等の多価フェノールの自己縮合物；又は多価ナフトールの自己縮合物等が用いられる。
スケール付着防止剤は、通常、適当な溶媒に溶解させた溶液または分散液からなる塗布液を調製して使用するのがよい。
上記の溶媒としては、例えばメタノール、エタノール等のアルコール類；アセトン、メチルエチルケトン、ジエチルケトン等のケトン類；Ｎ，Ｎ−ジメチルホルムアミド、ジメチルスルホキシド等の極性溶媒；フルフラール、テトラヒドロフラン等のエーテル類；エチレンジクロライド、塩化メチレン等のハロゲン化炭化水素類；ベンゼン、トルエン等の芳香族炭化水素類；水及びこれらの混合溶媒等が挙げられる。
Therefore, the configuration requirements of the present invention will be described.
(1) Scale adhesion preventing agent As the scale adhesion preventing agent, ordinary ones can be used.
As the scale adhesion inhibitor, for example, obtained by a condensation reaction of one or two or more compounds selected from polyaminobenzene, polyhydric phenol, aminophenol, alkyl-substituted aminophenol, diphenylamine or alkyl-substituted diphenolamine, Aromatic amines; self-condensates of polyhydric phenols such as resorcin, hydroquinone, catechol or phlorogrosin; or self-condensates of polyvalent naphthol are used.
As the scale adhesion preventing agent, it is usually preferable to prepare and use a coating solution comprising a solution or dispersion dissolved in an appropriate solvent.
Examples of the solvent include alcohols such as methanol and ethanol; ketones such as acetone, methyl ethyl ketone and diethyl ketone; polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide; ethers such as furfural and tetrahydrofuran; ethylene dichloride. And halogenated hydrocarbons such as methylene chloride; aromatic hydrocarbons such as benzene and toluene; water and a mixed solvent thereof.
（２）皮膜の形成
本発明のスケール付着防止剤の皮膜の形成は、重合反応器内にスケール付着防止剤を攪拌下に噴霧し、該重合反応器内壁に沿って上昇流を、また重合反応器中心部に下降流を生起させることにより、重合反応器内でスケール付着防止剤を循環させ、重合反応器内部表面にスケール付着防止剤を均一に塗布する点に特徴を有する。
本皮膜の形成法は、重合反応器の上部からスケール付着防止剤からなる塗布液を、撹拌下に噴霧することにより行うことが必須の要件であるが、その際の撹拌条件が重要であり、撹拌は、２種類のガス流、即ち、該反応器内壁に沿ってガス上昇流を、反応器中心部にガス下降流を、それぞれ生起させるとともに、重合反応器内でのスケール付着防止剤の循環を十分に行うものであることが必要がある。その結果、重合反応器の内部表面に均一な皮膜を形成することができる。
本皮膜の形成法は、重合反応器の大きさ等に影響を受けるので、撹拌は、以下の条件を満足するものを採用するのがよい。
重合反応器の内部表面近傍におけるスケール付着防止剤の流れを、鉛直方向の上昇流と水平方向の水平流に分解したとき、上昇流および水平流が、それぞれ下記式（１）及び（２）を満足するもの。
上昇流 １≦ｕｖ×ｔｖ／Ｌｖ≦８０ （１）
好ましくは３〜６０、更に好ましくは７〜５０とするのがよい。
水平流 ３≦ｕH ×ｔH ／ＬH ≦２４０ （２）
好ましくは１０〜２００、更に好ましくは２４〜１８０とするのがよい。
ただし、上記式中、
ｕｖ：上昇流の平均流速（０．３〜２ｍ／秒）
ｔｖ：上昇流を与える時間（秒）
Ｌｖ：重合反応器をその鉛直軸を通る鉛直平面で切断したときの断面内周（ｍ）
ｕH：水平流の平均流速（０．８〜５ｍ／秒）
ｔH：水平流を与える時間（秒）
ＬH：重合反応器を水平平面で切断したときの断面内周（ｍ）
蒸気のガス上昇流又はガス下降流のガス平均速度は、０．３〜２ｍ／秒とするのが好ましい。
噴霧は、スプレーノズルから散布することにより実施し得るが、このためのスプレーノズルは、一流体ノズルや二流体ノズル等の公知のものでよく、また個数は１個に限定されず、複数個のノズルを設置することもできる。
スプレー塗布による条件としては、通常、スプレー圧力１９６〜１９６０ＫＰａ（ゲージ圧）、好ましくは２９４〜７８５ＫＰａ（ゲージ圧）とするのがよい。
スプレー用ガスとしては、水蒸気、空気、窒素、一酸化炭素、塩化ビニル等が用いられる。
重合反応器内の気体重量に占めるスケール付着防止剤の重量は、スケール付着防止剤の効果を十分に発揮させると共に無駄な使用とならないようにするために、一般には０．０５〜０．１５％とするのが好ましい。
撹拌は、特別な攪拌装置を用意するよりは、重合反応器に付設された撹拌機をそのまま用いるのが有利である。
(2) Formation of film The film of the scale adhesion preventing agent of the present invention is formed by spraying the scale adhesion preventing agent into the polymerization reactor under stirring, and increasing the flow along the inner wall of the polymerization reactor. A down flow is caused in the central portion of the reactor to circulate the scale adhesion preventing agent in the polymerization reactor and uniformly apply the scale adhesion preventing agent to the inner surface of the polymerization reactor.
The formation method of this film is an essential requirement to perform by spraying a coating liquid composed of a scale adhesion inhibitor from the upper part of the polymerization reactor under stirring, but the stirring conditions at that time are important. Stirring generates two types of gas flows, that is, a gas upward flow along the inner wall of the reactor and a gas downward flow at the center of the reactor, and the circulation of the scale adhesion preventing agent in the polymerization reactor. Need to be sufficient. As a result, a uniform film can be formed on the inner surface of the polymerization reactor.
Since the formation method of this film is affected by the size of the polymerization reactor, etc., it is preferable to employ a stirring method that satisfies the following conditions.
When the flow of the scale adhesion preventing agent in the vicinity of the inner surface of the polymerization reactor is decomposed into a vertical upward flow and a horizontal horizontal flow, the upward flow and the horizontal flow are expressed by the following equations (1) and (2), respectively. Satisfied.
Upflow 1 ≦ u v × t v / L v ≦ 80 (1)
Preferably it is 3-60, More preferably, it is 7-50.
Horizontal flow 3 ≦ u H × t H / L H ≦ 240 (2)
It is preferably 10 to 200, more preferably 24 to 180.
However, in the above formula,
u v : Average flow velocity of upflow (0.3-2 m / sec)
tv : Time (seconds) to give upward flow
L v : inner circumference (m) when the polymerization reactor is cut along a vertical plane passing through its vertical axis
u H : Average flow velocity of horizontal flow (0.8 to 5 m / sec)
t H : Time for giving horizontal flow (seconds)
L H : Inner circumference of the cross section when the polymerization reactor is cut in a horizontal plane (m)
The average gas velocity of the vapor gas upward flow or gas downward flow is preferably 0.3 to 2 m / sec.
Spraying can be carried out by spraying from a spray nozzle. The spray nozzle for this purpose may be a known one such as a one-fluid nozzle or a two-fluid nozzle, and the number is not limited to one. A nozzle can also be installed.
The conditions for spray application are usually a spray pressure of 196 to 1960 KPa (gauge pressure), preferably 294 to 785 KPa (gauge pressure).
As the spray gas, water vapor, air, nitrogen, carbon monoxide, vinyl chloride, or the like is used.
The weight of the scale adhesion inhibitor in the weight of the gas in the polymerization reactor is generally 0.05 to 0.15% in order to sufficiently exhibit the effect of the scale adhesion inhibitor and avoid wasteful use. Is preferable.
For stirring, it is advantageous to use a stirrer attached to the polymerization reactor as it is rather than preparing a special stirring device.
（３）重合方法
重合反応器内部表面にスケール付着防止剤の皮膜の形成を行った後、該反応器内に所定の重合成分を供給して、常法により重合を行うが、この際、該反応器内部表面に均一にスケール付着防止剤皮膜が形成されているため、反応器内部表面へのスケール付着が防止され、重合体品質や生産性の低下を回避することができる。
本発明方法は、オレフィン単量体の重合時におけるスケール付着の防止に適用されるが、重合方法としては、例えば、塩化ビニル等のハロゲン化ビニル；酢酸ビニル、プロピオン酸ビニル等のビニルエステル；アクリル酸、メタクリル酸、これらのエステル又は塩；マレイン酸、フマル酸、これらのエステル又は無水物；ブタジエン、クロロプレン、イソプレン等のジエン；塩化ビニリデン等のハロゲン化ビニリデン；ビニルエーテル；スチレン；アクリロニトリル等の重合方法に適用し得る。特に、塩化ビニル等の塩化ビニル系単量体の重合方法に最適である。
また、スケール付着防止剤皮膜によるスケール防止効果は、モノマー以外に添加される各種の重合成分、例えば、重合開始剤（触媒）、水等の分散媒、懸濁剤、固体分散剤、カチオン性、アニオン性等の液体分散剤、充填剤、可塑剤、安定剤、連鎖移動剤、ｐＨ調整剤等が存在していた場合においても、十分発揮される。
従って、重合形式も特に制限されず、懸濁重合、乳化重合、溶液重合、塊状重合等の何れにも本発明方法を適用して、所望のスケール防止効果を発現させることができる。
(3) Polymerization method After forming a film of a scale adhesion inhibitor on the inner surface of the polymerization reactor, a predetermined polymerization component is supplied into the reactor and polymerization is carried out by a conventional method. Since the scale adhesion inhibitor film is uniformly formed on the inner surface of the reactor, scale adhesion to the inner surface of the reactor can be prevented, and deterioration of polymer quality and productivity can be avoided.
The method of the present invention is applied to prevent scale adhesion during polymerization of an olefin monomer. Examples of the polymerization method include vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; Acid, methacrylic acid, esters or salts thereof; maleic acid, fumaric acid, esters or anhydrides thereof; dienes such as butadiene, chloroprene, isoprene; vinylidene halides such as vinylidene chloride; vinyl ether; styrene; polymerization methods such as acrylonitrile Applicable to. In particular, it is most suitable for the polymerization method of vinyl chloride monomers such as vinyl chloride.
Moreover, the scale prevention effect by the scale adhesion preventing agent film has various polymerization components added in addition to the monomer, for example, a polymerization initiator (catalyst), a dispersion medium such as water, a suspension agent, a solid dispersion agent, a cationic property, Even when an anionic liquid dispersant, a filler, a plasticizer, a stabilizer, a chain transfer agent, a pH adjuster, or the like is present, it is sufficiently exerted.
Therefore, the polymerization mode is not particularly limited, and the method of the present invention can be applied to any of suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization, and the like, and a desired scale prevention effect can be exhibited.
（１）本発明によれば、重合反応器内部表面のスケール付着防止剤皮膜は均一に被覆されるので、長時間の連続運転が可能となり、一年間以上あるいは１０００バッチ以上の重合後であっても、スケール付着による生産停止の必要がない。
（２）従来方法のスプレー方式でスケール付着防止剤の塗布を行う方法では、特別な工夫をしない限り（例えば、特許文献３参照）、容積が８０ｍ３以上の大型重合反応器の内部表面にスケール付着防止剤皮膜を均一に形成することが困難であったが、本発明によれば、このような大型重合反応器を用いる場合においても、スケール付着防止剤皮膜を均一に形成することができる。
（３）本発明では、撹拌は必須であるが、その撹拌手段としては、例えば、重合反応器に付設された撹拌機をそのまま使用可能であるから有利である。
(1) According to the present invention, since the scale adhesion inhibitor film on the inner surface of the polymerization reactor is uniformly coated, continuous operation for a long time is possible, and after polymerization for one year or more or 1000 batches or more. However, there is no need to stop production due to scale adhesion.
(2) In the conventional method of applying the scale adhesion inhibitor by the spray method, unless special measures are taken (for example, see Patent Document 3), the scale is formed on the internal surface of a large polymerization reactor having a volume of 80 m 3 or more. Although it was difficult to form an adhesion inhibitor film uniformly, according to the present invention, even when such a large polymerization reactor is used, a scale adhesion inhibitor film can be formed uniformly.
(3) In the present invention, stirring is essential, but as the stirring means, for example, a stirrer attached to the polymerization reactor can be used as it is, which is advantageous.
以下、実施例等をあげて本発明をさらに詳細に説明するが、本発明はこれらのものに限定されない。
なお、以下の実施例および比較例において、ガス流速は以下の方法によって測定した。 直径４．２ｍ、高さ８．４ｍの重合反応器のガス水平流、上昇流の測定にあたっては、日本カノマックス社製の風速計（ＭＯＤＥＬ６０７１）を用いて、重合反応器の内壁より５００ｍｍ離れた重合反応器底部挿入の撹拌翼上部より３０００ｍｍ上方の位置に、風速計センサーを取り付け固定し、鉛直中心線に並行して上昇するガス流速（上昇流）を、及び水平方向に旋回するガス流速（水平流）の風速を計測した。
重合反応器鉛直中心線まわりを下降する下降ガス流の測定は、上記風速計センサーを重合反応器上鏡部の中心位置ノズルから挿入し、上鏡部より３ｍ下の位置に固定して計測した。下降するガス流速は、上記の方法で測定した上昇流と同じ値であった。
（実施例１）
懸濁重合法で塩化ビニル樹脂を回分式で重合する反応器（直径４．２ｍ、長さ８．４ｍ、上下鏡部１：２楕円、付属装置：内部ジャケット、ファウドラー後退翼、Ｄ型バッフル内臓、還流式熱交換器付属）を使用し、月間およそ２００バッチの平均重合度１０４０のパイプ用ＰＣＶを製造するプロセスにおいて、重合反応器に塩化ビニルモノマー４１．４ｍ３、脱塩水４１．４ｍ３、分散剤Ａ７００ｐｐｍ（対モノマー、ポリビニルアルコールケン化度８０モル％）、分散剤Ｂ１５０ｐｐｍ（対モノマー、ポリビニルアルコール、ケン化度３５モル％）及び油溶性開始剤（有機過酸化物）６００ｐｐｍ(対モノマー)を添加して撹拌し、反応温度を５７℃に調節しながら反応を進め、重合率２５％に到達する前までに、重合反応器内の非凝縮ガス（主に窒素ガス）を還流熱交換器の頂部に設けたイナートガスベント弁を一定時間開けて、重合反応器及び還流熱交換器から系外へ移動させ、重合率が２５％に到達した頃に、還流熱交換器のジャケットに冷却水を通し、冷却を開始させ、冷却開始５０分後には、除熱量を５８５０ＭＪ／Ｈｒまで上昇させて反応を進めた。反応が進み、重合反応器圧力が６３７ＫＰａ（ゲージ圧）に到達したときに反応を打ち切り、重合反応器底に設置された重合スラリー抜き出し弁を開けてスラリーを脱ガス槽に取り出した後、反応器内の残圧を反応器気相部に設置したモノマー回収弁を開けて、重合反応器内圧力が３９ＫＰａ（ゲージ圧）に達するまで未反応モノマーを回収した。回収途中、高圧水ジェット洗浄装置による反応器内のジェット洗浄を始め、ジェット洗浄後に次バッチの重合のために、スケール付着防止剤の散布を実施した。
スケール付着防止剤の散布は、はじめに反応器内の残液なしの確認からスタートし、噴霧媒体（蒸気）とスケール付着防止剤を装入する配管内を蒸気によるブローを行って、配管内のドレンを排出させた後、重合反応器撹拌翼電動機を始動させて、回転速度を３０ｒ／ｍ（翼周速度＝４ｍ／秒）に調整し、次いで、スケール付着防止剤（多価フエノール縮合反応生成物）の噴霧を実施した。蒸気の圧力は４９０ＫＰａ（ゲージ圧）、流量は５００ｋｇ／Ｈｒ、スケール付着防止剤は２４０ｋｇ／Ｈｒの速度で蒸気配管内に装入した。重合反応器残留モノマーに対し０．１４重量（％）の量が装入された時に散布を停止し、撹拌翼は噴霧開始より２分間経過した時に停止した。その後２分間の放置を経て反応器内を脱塩水により水洗し、排水した。この後、次バッチの仕込み、反応、スラリーのブローダウン、未反応モノマーの回収、ジェット洗浄を繰り返し行った。
バッチ重合操作を繰返しながら、高圧水ジェット洗浄により発生するドレンの排出時に、反応器内からスケールが取り出されるので、毎バッチあるいは日毎のスケール量の計測を行って、スケール付着防止剤散布効果を確認した。バッチ毎の平均スケール発生量は３３４グラムであった。１０００バッチ以上（１年間）連続して生産が行えた。途中３ヶ月毎に、重合反応器内部を目視確認したが、重合反応器内局部にスケール発生はなく、バッフルの裏にこぶし大のスケールが観察されたのみであった。
EXAMPLES Hereinafter, although an Example etc. are given and this invention is demonstrated further in detail, this invention is not limited to these.
In the following examples and comparative examples, the gas flow rate was measured by the following method. For measurement of gas horizontal flow and upward flow in a polymerization reactor having a diameter of 4.2 m and a height of 8.4 m, an anemometer (MODEL6071) manufactured by Nippon Kanomax Co., Ltd. was used to conduct polymerization at a distance of 500 mm from the inner wall of the polymerization reactor. An anemometer sensor is attached and fixed at a position 3000 mm above the top of the stirring blade at the bottom of the reactor, and the gas flow rate (upflow) rising parallel to the vertical center line and the gas flow rate (horizontal) swirling horizontally Wind speed) was measured.
The measurement of the descending gas flow descending around the vertical center line of the polymerization reactor was measured by inserting the anemometer sensor from the central position nozzle of the upper mirror part of the polymerization reactor and fixing it at a position 3 m below the upper mirror part. . The descending gas flow rate was the same value as the ascending flow measured by the above method.
Example 1
Reactor for batch polymerization of vinyl chloride resin by suspension polymerization method (Diameter 4.2m, Length 8.4m, Vertical mirror part 1: 2 ellipse, Attached equipment: Internal jacket, Faudler receding blade, D-type baffle internal organs , using a reflux heat exchanger included), in the process for producing the pipe for PCV average polymerization degree 1040 monthly approximately 200 batch, the polymerization reactor in a vinyl chloride monomer 41.4M 3, demineralized water 41.4M 3, Dispersant A 700 ppm (with respect to monomer, polyvinyl alcohol saponification degree 80 mol%), Dispersant B 150 ppm (with respect to monomer, polyvinyl alcohol, saponification degree 35 mol%), and oil-soluble initiator (organic peroxide) 600 ppm (with respect to monomer) Is added and stirred, the reaction proceeds while adjusting the reaction temperature to 57 ° C., and the non-condensation in the polymerization reactor is reached before the polymerization rate reaches 25%. When the inert gas vent valve provided with the gas (mainly nitrogen gas) at the top of the reflux heat exchanger was opened for a certain period of time and moved out of the system from the polymerization reactor and the reflux heat exchanger, the polymerization rate reached 25% Then, cooling water was passed through the jacket of the reflux heat exchanger to start cooling, and after 50 minutes from the start of cooling, the heat removal amount was increased to 5850 MJ / Hr to proceed the reaction. When the reaction proceeds and the polymerization reactor pressure reaches 637 KPa (gauge pressure), the reaction is terminated, and after opening the polymerization slurry extraction valve installed at the bottom of the polymerization reactor, the slurry is taken out into the degassing tank. The monomer recovery valve in which the residual pressure in the reactor was installed in the gas phase of the reactor was opened, and the unreacted monomer was recovered until the pressure in the polymerization reactor reached 39 KPa (gauge pressure). During the recovery, jet cleaning in the reactor was started with a high-pressure water jet cleaning apparatus, and after the jet cleaning, a scale adhesion inhibitor was sprayed for polymerization of the next batch.
The spraying of the scale adhesion inhibitor starts with the confirmation that there is no residual liquid in the reactor, and the spray medium (steam) and the pipe into which the scale adhesion inhibitor is charged are blown with steam to drain the pipe. Then, the polymerization reactor stirring blade motor was started to adjust the rotation speed to 30 r / m (blade peripheral speed = 4 m / second), and then the scale adhesion inhibitor (polyhydric phenol condensation reaction product). ) Was sprayed. The steam pressure was 490 KPa (gauge pressure), the flow rate was 500 kg / Hr, and the scale adhesion inhibitor was charged into the steam pipe at a rate of 240 kg / Hr. The spraying was stopped when an amount of 0.14% by weight (%) relative to the polymerization reactor residual monomer was charged, and the stirring blade was stopped when 2 minutes had elapsed from the start of spraying. Thereafter, after leaving for 2 minutes, the inside of the reactor was washed with demineralized water and drained. Thereafter, the preparation of the next batch, reaction, blow-down of the slurry, recovery of unreacted monomers, and jet cleaning were repeated.
The scale is taken out from the reactor when draining generated by high-pressure water jet washing while repeating the batch polymerization operation, so measure the amount of scale every batch or day to confirm the spraying effect of the scale adhesion inhibitor. did. The average scale generation per batch was 334 grams. Over 1000 batches (1 year) were produced continuously. The inside of the polymerization reactor was visually confirmed every 3 months, but no scale was generated in the local portion of the polymerization reactor, and only a large scale was observed on the back of the baffle.
（実施例２）
撹拌翼をスケール付着防止剤の噴霧開始より５分経過した時に停止したこと以外は、実施例１と同様にして重合バッチを繰返し行い、バッチ毎の平均スケール量は６３グラム、１０００バッチ以上連続して生産が行えた。途中３ヶ月毎に、重合反応器内部を目視確認したが、重合反応器内局部にスケール発生はなく、バッフルの裏に僅かなスケールが観察されたに過ぎなかった。
(Example 2)
The polymerization batch was repeated in the same manner as in Example 1 except that the stirring blade was stopped when 5 minutes had elapsed from the start of spraying of the scale adhesion inhibitor, and the average scale amount for each batch was 63 grams, 1000 batches or more continuous. Production was possible. The inside of the polymerization reactor was visually confirmed every 3 months, but no scale was generated in the local portion of the polymerization reactor, and only a slight scale was observed on the back of the baffle.
（実施例３）
スケール付着防止剤量を残留ガスに対し０．１３重量（％）とし、散布中の撹拌翼回転数を８０ｒ／ｍ、撹拌付与時間を３分間に変更して散布した以外は、実施例１と同様にして重合バッチを繰り返して行い、バッチ毎の平均スケール量は３４グラム、１０００バッチ以上連続して生産が行えた。途中３ヶ月毎に、重合反応器内部を目視確認したが、重合反応器内局部にスケール発生はなく、バッフルの裏に僅かなスケールが観察されたに過ぎなかった。
(Example 3)
Example 1 except that the amount of scale adhesion inhibitor was 0.13 weight (%) with respect to the residual gas, the stirring blade rotation speed during spraying was changed to 80 r / m, and the stirring application time was changed to 3 minutes. Similarly, the polymerization batch was repeated, and the average scale amount for each batch was 34 grams, and production could be continuously performed for 1000 batches or more. The inside of the polymerization reactor was visually confirmed every 3 months, but no scale was generated in the local portion of the polymerization reactor, and only a slight scale was observed on the back of the baffle.
（実施例４）
スケール付着防止剤量を残留ガスに対し０．０７重量（％）とし、散布中の撹拌翼回転数を８０ｒ／ｍ、撹拌付与時間を５分間に変更して散布した以外は、実施例１と同様にして重合バッチを繰り返して行い、バッチ毎の平均スケール量は２２グラム、１０００バッチ以上連続して生産が行えた。途中３ヶ月毎に、重合反応器内部を目視確認したが、重合反応器内局部にスケール発生はなく、バッフルの裏に僅かなスケールが観察されたに過ぎなかった。
Example 4
Example 1 except that the amount of the scale adhesion inhibitor is 0.07% by weight (%) with respect to the residual gas, the stirring blade speed during spraying is changed to 80 r / m, and the stirring application time is changed to 5 minutes. In the same manner, the polymerization batch was repeated, and the average scale amount for each batch was 22 grams, and production could be continuously performed for 1000 batches or more. The inside of the polymerization reactor was visually confirmed every 3 months, but no scale was generated in the local portion of the polymerization reactor, and only a slight scale was observed on the back of the baffle.
（実施例５）
スケール付着防止散布量を残留ガスに対し０．０７重量（％）とし、散布中の撹拌翼回転数を８０ｒ／ｍ、撹拌付与時間を１５分間に変更して散布した以外は、実施例１と同様にして重合バッチを繰り返して行い、バッチ毎の平均スケール量は１５グラム、１０００バッチ以上連続して生産が行えた。途中３ヶ月毎に、重合反応器内部を目視確認したが、重合反応器内局部にスケール発生はなく、バッフルの裏に僅かなスケールが観察されたに過ぎなかった。
(Example 5)
Example 1 except that the scale adhesion prevention spraying amount was 0.07 weight (%) with respect to the residual gas, the stirring blade rotation speed during spraying was changed to 80 r / m, and the stirring application time was changed to 15 minutes. In the same manner, the polymerization batch was repeated, and the average scale amount for each batch was 15 grams, and production could be continuously performed for 1000 batches or more. The inside of the polymerization reactor was visually confirmed every 3 months, but no scale was generated in the local portion of the polymerization reactor, and only a slight scale was observed on the back of the baffle.
（比較例１）
スケール付着防止剤を撹拌翼を回さないで噴霧し、スケール付着防止剤散布量を残量ガスに対して、０．１３重量（％）として実施した以外は実施例１と同様にして重合バッチを繰り返して行い、バッチ毎の平均スケール量は８３３グラム、２００バッチ連続して生産し終えた頃より、スケールの発生量が増えはじめ２０００グラムを超えるために２８８バッチ生産し終えた後、生産を停止して、重合反応器内を目視確認したところ、局所にスケールの存在が認められ、バッフル裏にはスケールが多量に存在していた。３ケ月の連続生産には至らず、重合反応器内に人が入ってスケールの除去を２日間に渡って行った。
(Comparative Example 1)
Polymerization batch in the same manner as in Example 1, except that the scale adhesion inhibitor was sprayed without rotating the stirring blade and the amount of the scale adhesion inhibitor sprayed was 0.13 weight (%) with respect to the remaining gas. Repeatedly, the average scale amount per batch was 833 grams, and since the production of scale began to increase and exceeded 2,000 grams from the time when 200 batches were continuously produced, After stopping and visually checking the inside of the polymerization reactor, the presence of scale was found locally, and a large amount of scale was present behind the baffle. The continuous production of 3 months was not reached, and a person entered the polymerization reactor to remove the scale over 2 days.
表１の結果から、本発明の方法により、スケール付着防止剤を撹拌し、噴霧すると、優れたスケール付着防止効果が達成されることが解る。 From the results of Table 1, it can be seen that when the scale adhesion inhibitor is stirred and sprayed by the method of the present invention, an excellent scale adhesion prevention effect is achieved.
塩化ビニルモノマーの重合の場合、塩化ビニルモノマーは有害であり、大気中に放出される量を削減する取り組みがなされているだけに、本発明の重合反応器内部表面のスケール防止方法は、非常に有用な技術である。
In the case of polymerization of vinyl chloride monomer, vinyl chloride monomer is harmful, and since efforts have been made to reduce the amount released to the atmosphere, the method for preventing scale on the inner surface of the polymerization reactor of the present invention is very It is a useful technique.
Claims (4)
上昇流 １≦ｕｖ×ｔｖ／Ｌｖ≦８０ （１）
水平流 ３≦ｕH ×ｔH ／ＬH ≦２４０ （２）
ただし、上記式中、
ｕｖ：上昇流の平均流速（０．３〜２ｍ／秒）
ｔｖ：上昇流を与える時間（秒）
Ｌｖ：重合反応器をその鉛直軸を通る鉛直平面で切断したときの断面内周（ｍ）
ｕH：水平流の平均流速（０．８〜５ｍ／秒）
ｔH：水平流を与える時間（秒）
ＬH：重合反応器を水平平面で切断したときの断面内周（ｍ） When the flow of the scale adhesion inhibitor near the inner surface of the polymerization reactor is decomposed into a vertical upward flow and a horizontal horizontal flow, the upward flow and the horizontal flow satisfy the following formulas (1) and (2), respectively. The coating method of the scale adhesion preventing agent according to claim 1 or 2.
Upflow 1 ≦ u v × t v / L v ≦ 80 (1)
Horizontal flow 3 ≦ u H × t H / L H ≦ 240 (2)
However, in the above formula,
u v : Average flow velocity of upflow (0.3-2 m / sec)
tv : Time (seconds) to give upward flow
L v : inner circumference (m) when the polymerization reactor is cut along a vertical plane passing through its vertical axis
u H : Average flow velocity of horizontal flow (0.8 to 5 m / sec)
t H : Time for giving horizontal flow (seconds)
L H : Inner circumference of the cross section when the polymerization reactor is cut in a horizontal plane (m)
The method for applying a scale adhesion preventing agent according to claim 1, 2 or 3, wherein the weight of the scale adhesion inhibiting agent in the gas weight in the polymerization reactor is 0.05 to 0.15%.
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| JP2016529247A (en) * | 2013-08-08 | 2016-09-23 | ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ | Process for removing cobalt deposits in reactors for high pressure hydroformylation of olefins |
| CN113861336A (en) * | 2021-10-19 | 2021-12-31 | 江苏恒神股份有限公司 | Inhibition method for continuous polymerization gel of acrylonitrile |
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| JP2016529247A (en) * | 2013-08-08 | 2016-09-23 | ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ | Process for removing cobalt deposits in reactors for high pressure hydroformylation of olefins |
| US10385422B2 (en) | 2013-08-08 | 2019-08-20 | Basf Se | Method for removing cobalt deposits in a high-pressure olefin hydroformylation reactor |
| CN113861336A (en) * | 2021-10-19 | 2021-12-31 | 江苏恒神股份有限公司 | Inhibition method for continuous polymerization gel of acrylonitrile |
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