塩化ビニル系樹脂は、難燃性、絶縁性、断熱性等に優れた特性を備えた樹脂であるので、世界的にみても幅広い分野に使用されており、極めて有用な樹脂である。
塩化ビニル系樹脂は、通常、懸濁重合法、乳化重合法、塊状重合法等によって製造されるが、反応熱を除去し易いこと、不純物の少ない製品を得ることができること、重合後の塩化ビニル系樹脂が粒子状であるため造粒工程が不要であること等の理由から、懸濁重合法や乳化重合法が広く採用されている。
この懸濁重合法や乳化重合法は、通常、塩化ビニル、水性媒体、分散剤、重合開始剤等を攪拌機付き重合反応器内で、所定温度に保ちながら攪拌することによって行われるが、重合反応は、塩化ビニルが１００％塩化ビニル系樹脂となるまで行われることはなく、通常、製造効率のよい段階、即ち、重合転化率８０〜９５％の段階で停止される。
その後、重合反応器を脱圧することで未反応モノマーを取り出し、あるいは重合反応器から脱ガス槽に塩化ビニル系樹脂スラリーをブローダウン（取卸し）して脱ガス槽に受けたのち、脱ガス槽の圧力を大気圧まで脱圧すると、塩化ビニル系樹脂スラリーには約２％の未反応モノマーが存在する。
Vinyl Le chloride resins, flame retardancy, insulation, since a resin having excellent characteristics in insulation resistance and the like, and in the world are used to a wide range of fields, is an extremely useful resin.
The vinyl chloride resin is usually produced by suspension polymerization, emulsion polymerization, bulk polymerization, etc., but it is easy to remove reaction heat, obtain a product with less impurities, and vinyl chloride after polymerization. The suspension polymerization method and the emulsion polymerization method are widely adopted because the granulated step is unnecessary because the system resin is in the form of particles.
This suspension polymerization method or emulsion polymerization method is usually performed by stirring vinyl chloride, an aqueous medium, a dispersant, a polymerization initiator, etc. in a polymerization reactor equipped with a stirrer while maintaining a predetermined temperature. Is not carried out until the vinyl chloride becomes 100% vinyl chloride resin, and is usually stopped at a stage where the production efficiency is high, that is, at a stage where the polymerization conversion is 80 to 95%.
Then, unreacted monomer is taken out by depressurizing the polymerization reactor, or after the vinyl chloride resin slurry is blown down from the polymerization reactor to the degassing tank and received in the degassing tank, the degassing tank When the pressure is released to atmospheric pressure, about 2% of unreacted monomers are present in the vinyl chloride resin slurry.
従来から、上記塩化ビニル系樹脂スラリーから塩化ビニルを除去する方法が開発されており、例えば、(1)約６０〜９０℃に予熱された重合体分散液を、その段板をそれぞれ少なくとも１つの、偏心に配置された水分散液用の流下管が貫通している変更多孔板塔の上部に段板の面積１ｍ２当たり毎時約５〜３５ｍ３の量で連続的に導入し、これに対し向流で約０．５〜５バールの圧力下の約８０〜１５０℃の熱水蒸気で、分散液１ｍ３当たり蒸気３０〜１００ｋｇの蒸気負荷率において約１〜３０分の平均滞留時間処理し、その際１つの段板を通過するときの、塔内の蒸気の圧損失は好ましくない１つの流下管を通過するときよりも小さく、かつ単量体を除去精製された分散液は塔の底部で取出し、塔の頂部から流出する蒸気混合物は水相ならびに単量体を得るために凝縮させることにより、重合体分散液から単量体を連続的に除去する方法（特許文献１）、(2)塩化ビニルモノマーを含む塩化ビニル樹脂スラリーの流出経路を必要とする少なくとも１つの多孔板を備えた容器（塔を含む）にスラリーを供給し、該スラリーを前記多孔板上において該多孔板の多数の細孔から吹き込まれる水蒸気で処理して該スラリー中の塩化ビニルモノマーを除去する方法において、前記処理の間前記多孔板の下面を間欠的または連続的に温水噴射により洗浄することにより、重合体分散液から塩化ビニルモノマーを除去する方法（特許文献２）、(3)充填塔に入る前の懸濁液もしくは乳濁液を熱交換器の低温入口部に導入し、該熱交換器より出た懸濁液もしくは乳濁液を充填塔に送入し、一方、充填塔で未反応塩化ビニルモノマーが除去された懸濁液もしくは乳濁液を該熱交換器の高温供給部入口へ導入し、充填塔へ送られる懸濁液もしくは乳濁液の加熱媒体となし、該熱交換器で充填塔へ送られる懸濁液もしくは乳濁液を加熱したのちに該熱交換器より出た懸濁液もしくは乳濁液を２つの流れに分け第１の流れを乾燥工程へ送り、第２の流れを充填塔の塔底へリサイクルすること、及び、充填塔内部で未反応塩化ビニルモノマーがストリッピングされ充填塔の塔頂部から系外へ排出されるに際し、未反応塩化ビニルモノマーと共に排出される水蒸気が凝縮され、該凝縮水が充填塔の塔頂部のリサイクルされることにより、重合体分散液から塩化ビニルモノマーを除去する方法（特許文献３）等が挙げられる。
Conventionally, the provided method for removing vinyl chloride from vinyl chloride resin slurry is developed, for example, (1) the polymer dispersions heated reserved to about 60 to 90 ° C., at least the stage plate respectively 1 One of the continuously introduced in an amount of area 1 m 2 per hour about 5～35M 3 of the upper to the stage plate changes perforated plate tower flows down pipe for water dispersion are arranged on the eccentric penetrates, to In the counter-current, with a steam of about 80 to 150 ° C. under a pressure of about 0.5 to 5 bar, an average residence time of about 1 to 30 minutes is treated at a steam load factor of 30 to 100 kg of steam per 1 m 3 of dispersion. In this case, the pressure loss of the vapor in the column when passing through one step plate is smaller than that when passing through one undesired downcomer, and the dispersion obtained by removing the monomer is purified at the bottom of the column. The vapor mixture flowing out from the top of the tower And a method for continuously removing the monomer from the polymer dispersion by condensing to obtain a monomer (Patent Document 1), and (2) the flow path of the vinyl chloride resin slurry containing the vinyl chloride monomer. The slurry is supplied to a container (including a tower) provided with at least one perforated plate required, and the slurry is treated with water vapor blown from a large number of pores of the perforated plate on the perforated plate. In the method of removing vinyl chloride monomer, a method of removing vinyl chloride monomer from a polymer dispersion by washing the lower surface of the perforated plate intermittently or continuously with hot water jet during the treatment (Patent Document 2). ), (3) The suspension or emulsion before entering the packed tower is introduced into the low temperature inlet of the heat exchanger, and the suspension or emulsion discharged from the heat exchanger is sent to the packed tower. On the other hand, filling The suspension or emulsion from which the unreacted vinyl chloride monomer has been removed in step 1 is introduced into the high-temperature supply section inlet of the heat exchanger, and is used as a heating medium for the suspension or emulsion sent to the packed tower. After heating the suspension or emulsion sent to the packed tower in the heat exchanger, the suspension or emulsion coming out of the heat exchanger is divided into two streams and the first stream is sent to the drying process Recycling the second stream to the bottom of the packed tower and unreacted vinyl chloride monomer stripped inside the packed tower and discharged out of the system from the top of the packed tower. A method of removing the vinyl chloride monomer from the polymer dispersion by condensing the water vapor discharged together with the condensed water and recycling the condensed water at the top of the packed tower (Patent Document 3) and the like.
（２）塩化ビニルモノマーの除去
１）脱モノマー塔
塩化ビニルモノマーの除去は、脱モノマー塔を用いて行われるが、該塔としては、通常のもの、例えば、棚段式脱モノマー塔や充填塔式脱モノマー塔等が使用することが出来る。
棚段式脱モノマー塔方式は、塩化ビニル系樹脂スラリーの流出通路を設けた少なくとも１つの多孔板を備えた塔にスラリーを供給し、該スラリーを多孔板上において、該多孔板の多数の細孔から吹き込まれた９０〜１２０℃の熱水蒸気で処理して、スラリー中の塩化ビニルを除去する方法である。
また、充填塔式脱モノマー塔方式は、塩化ビニル系樹脂スラリーを充填塔内で水蒸気と向流接触させてスラリー中の塩化ビニルモノマーを除去する方法であって、充填塔中の充填物としては、ラシヒリング、ペルルサドル、テラレットパッキング、ボールリング、レッシングリング、インターロッキングサドル等が用いられている。
(2) Removal of vinyl chloride monomer 1) Demonomer tower The removal of vinyl chloride monomer is carried out using a demonomer tower. Examples of the tower include ordinary ones such as a plate-type demonomer tower and a packed tower. A formula demonomer tower or the like can be used.
In the shelf type demonomer tower system, the slurry is supplied to a tower having at least one perforated plate provided with an outflow passage for the vinyl chloride resin slurry, and the slurry is placed on the perforated plate. This is a method of removing vinyl chloride in the slurry by treating with hot steam at 90 to 120 ° C. blown from the holes.
The packed tower type demonomer tower system is a method in which a vinyl chloride resin slurry is brought into countercurrent contact with water vapor in the packed tower to remove the vinyl chloride monomer in the slurry. , Raschig rings, Perurusadoru, Terare' door packing, ball ring, Lessing ring, interlocking saddle or the like is used.