JP2618589B2 - Ethylene recovery method - Google Patents
Ethylene recovery methodInfo
- Publication number
- JP2618589B2 JP2618589B2 JP5172057A JP17205793A JP2618589B2 JP 2618589 B2 JP2618589 B2 JP 2618589B2 JP 5172057 A JP5172057 A JP 5172057A JP 17205793 A JP17205793 A JP 17205793A JP 2618589 B2 JP2618589 B2 JP 2618589B2
- Authority
- JP
- Japan
- Prior art keywords
- ethylene
- membrane
- polymer
- gas
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/144—Purification; Separation; Use of additives using membranes, e.g. selective permeation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/03—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by addition of hydroxy groups to unsaturated carbon-to-carbon bonds, e.g. with the aid of H2O2
- C07C29/04—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by addition of hydroxy groups to unsaturated carbon-to-carbon bonds, e.g. with the aid of H2O2 by hydration of carbon-to-carbon double bonds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、高分子膜を用いる膜
分離法によるエチレンの回収方法に係り、更に詳記すれ
ば、触媒を用いたエチレンの水和反応によりエタノール
を製造する際に、循環未反応エチレン流のパージガス中
に含まれる水素、窒素、メタン及びエタン等の不活性ガ
ス並びに炭素数４以上の炭化水素成分（以下Ｃ４+ポリ
マーと称す。）を、ゴム状高分子膜を用いる膜分離法に
よりエチレンと分離させるエチレンの回収方法に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering ethylene by a membrane separation method using a polymer membrane, and more particularly, to a method for producing ethanol by a hydration reaction of ethylene using a catalyst. An inert gas such as hydrogen, nitrogen, methane and ethane and a hydrocarbon component having 4 or more carbon atoms (hereinafter referred to as C4 + polymer) contained in the purge gas of the circulating unreacted ethylene stream are formed using a rubber-like polymer membrane. The present invention relates to a method for recovering ethylene separated from ethylene by a membrane separation method.
【０００２】[0002]
【従来の技術】触媒、例えば燐酸，硫酸等の鉱酸類、ケ
イタングステン酸，リンモリブデン酸等のヘテロポリ酸
類、酸化タングステン，シリカアルミナ或はニオブ酸等
の金属酸化物またはゼオライト類、を用いたエチレンの
水和反応によりエタノールを製造することは公知であ
る。この方法は、一般的に適用される温度、圧力及び水
／エチレンのモル比等の反応条件下では、反応平衡の制
約により、１回通過のエチレンのエタノールへの転化率
は、高々６％程度に過ぎない。そこで、大量の未反応エ
チレンを循環ガスとして操作し、反応に再度供すること
により、エタノールの全収率を通常約９６％に向上させ
ている。この反応の副反応生成物は、主としてジエチル
エーテルであり、その他に例えば少量のアセトアルデヒ
ドやアセトン等のカルボニル化合物が生成する。エチレ
ンの約１〜２％がエチレンの二〜五量体の飽和及び不飽
和の炭化水素等の前記したＣ４+ポリマーに変化する。
また、エチレンの二〜五量体に対応した少量の高級アル
コール類も副生する。2. Description of the Related Art Ethylene using catalysts such as mineral acids such as phosphoric acid and sulfuric acid, heteropolyacids such as silicotungstic acid and phosphomolybdic acid, metal oxides such as tungsten oxide, silica alumina and niobic acid, and zeolites. It is known to produce ethanol by a hydration reaction of Under the generally applied reaction conditions such as temperature, pressure and water / ethylene molar ratio, the conversion of ethylene to ethanol in a single pass is at most about 6% due to the restriction of reaction equilibrium. It's just Therefore, by operating a large amount of unreacted ethylene as a circulating gas and re-using the same for the reaction, the overall yield of ethanol is usually improved to about 96%. A side reaction product of this reaction is mainly diethyl ether, and other small amounts of carbonyl compounds such as acetaldehyde and acetone are produced. About 1-2% of the ethylene is converted to the aforementioned C4 + polymer, such as saturated and unsaturated hydrocarbons of ethylene di- to pentamer.
In addition, a small amount of higher alcohols corresponding to dimer to pentamer of ethylene is also by-produced.
【０００３】Ｃ４+ポリマーは、炭素数約１０位までの
ものであり、通常の反応条件下ではガス状であるが、こ
れら低分子量のポリマーから逐次高分子量のポリマーが
生成され、主反応生成物であるエタノールと共に下流の
反応系外にわずかに除去されることにより、一定に保た
れる平衡状態になるまで蓄積する。この高分子量のポリ
マーは、操作上重大な障害を惹起する。例えば、触媒表
面を覆うことによって、活性の低下や触媒寿命の短縮が
引き起こされるほか、反応塔からの流出物を冷却する熱
交換器の流入口に沈着物を形成させたり、圧縮機及び／
或は下流にあるエタノールを濃縮精製するための蒸留塔
を汚染する。従って、このような高分子量のポリマーの
生成を防止するため、循環未反応エチレン流中に低分子
量のポリマーが高い比率で存在する事態は避ける必要が
ある。[0003] C4 + polymers are those having up to about 10 carbon atoms and are gaseous under ordinary reaction conditions. However, these low molecular weight polymers are successively formed into high molecular weight polymers, and the main reaction product Is slightly removed out of the downstream reaction system together with ethanol, which accumulates until an equilibrium state is maintained. This high molecular weight polymer causes significant operational obstacles. For example, covering the catalyst surface causes a decrease in activity and a reduction in the life of the catalyst. In addition, deposits are formed at the inlet of a heat exchanger that cools the effluent from the reaction tower, and a compressor and / or
Or, it contaminates the distillation column for concentrating and purifying the downstream ethanol. Therefore, in order to prevent the production of such a high molecular weight polymer, it is necessary to avoid a situation where a low molecular weight polymer is present in a high ratio in the circulating unreacted ethylene stream.
【０００４】また原料エチレン中には、少量の窒素、水
素、メタン及びエタン等の不活性ガスが含まれている。
これらの不活性ガスは、高分子量ポリマーのように反応
操作に重大な障害を引き起こすことはないが、反応系外
に抜き出される量は微量であるので、次第に循環未反応
エチレン流中に蓄積し、エチレン濃度が低下する。エタ
ノールの生成量はエチレン濃度に比例することから、エ
チレン濃度を高めに維持することも重要である。ジエチ
ルエーテルはエタノール及び水と反応平衡にあるので、
反応操作上特段の問題はない。またアセトアルデヒド、
アセトン等のカルボニル化合物及び高級アルコール類
は、水を用いた吸収操作により主反応生成物であるエタ
ノールと一緒に下流の反応系外に抜き出されるので蓄積
することはなく、ジエチルエーテルと同様に反応上特段
の問題はない。Further, a small amount of inert gas such as nitrogen, hydrogen, methane and ethane is contained in the raw material ethylene.
These inert gases do not cause serious obstacles to the reaction operation unlike high-molecular-weight polymers, but the amount extracted out of the reaction system is very small, so they gradually accumulate in the circulated unreacted ethylene stream. , Lowering the ethylene concentration. Since the amount of ethanol produced is proportional to the ethylene concentration, it is also important to keep the ethylene concentration high. Since diethyl ether is in equilibrium with ethanol and water,
There is no particular problem in the reaction operation. Acetaldehyde,
Carbonyl compounds such as acetone and higher alcohols are extracted out of the downstream reaction system together with the main reaction product, ethanol, by the absorption operation using water, so they do not accumulate and react similarly to diethyl ether. There is no particular problem.
【０００５】公知方法では循環未反応エチレン流の一部
をパージガスとして排出し、精製処理することにより循
環未反応エチレン流中のエチレン濃度を約８５％程度に
保つのが普通である。なぜならば、循環未反応エチレン
流中の不純物の増加量はそれほど大きくないからであ
り、エチレン濃度を高くすると反応は増大するので、製
造装置の建設費や製造エネルギー経費は減少するが、排
出すべきガス量を著しく増大させねばならず精製処理費
の増大やエチレンの損失量の増加を招き、結局、経済性
を悪化させるからである。また、エチレン濃度が８５％
を著しく下回るような操作方法は、エタノールの生成量
がエチレン濃度に比例することから、生産量が低下する
だけでなく、Ｃ４+ポリマーの蓄積により前述した種々
の重大な障害を惹起する。In a known method, a part of the circulated unreacted ethylene stream is discharged as a purge gas, and is subjected to a purification treatment to maintain the ethylene concentration in the circulated unreacted ethylene stream at about 85%. This is because the increase in the amount of impurities in the circulated unreacted ethylene stream is not so large, and the higher the ethylene concentration, the higher the reaction. This is because the amount of gas must be significantly increased, which leads to an increase in the cost of the refining process and an increase in the amount of loss of ethylene, which ultimately deteriorates the economic efficiency. The ethylene concentration is 85%
The operation method significantly lower than the above results not only in a decrease in the production amount because the production amount of the ethanol is proportional to the ethylene concentration, but also causes the various serious obstacles described above due to the accumulation of the C4 + polymer.
【０００６】循環未反応エチレン流中のＣ４+ポリマー
を減らすための公知の処理方法としては、深冷或は低温
蒸留法（米国特許第３，８２７，２４５号、特公昭５１
ー９７２８号）及び重質炭化水素による吸収法（特開昭
４８ー１５８０５号）が開示されている。米国特許第
３，８２７，２４５号によれば、エチレン濃度８５〜９
５％の循環未反応エチレン流の一部を抜き出し、アルミ
ナ等の乾燥剤が充填されているドライヤーに導き、該ガ
ス流を乾燥させ、深冷蒸留塔に供給する。深冷蒸留塔の
操作圧力は、約２９０ＰＳＩＧ（１９．７気圧）、塔頂
温度は約−１９°Ｆ（−２８．３℃）、塔底温度は約＋
２６０°Ｆ（＋１２６．７℃）とし、塔頂流をコンデン
サーで約−２２°Ｆ（−３０℃）まで冷却し塔頂に還流
させる。還流液のエチレン濃度は９７〜９９％まで精製
される。還流液の一部を抜き出し回収エチレンとして反
応系に再循環させる。この方法は、エチレンの精製度合
が高いので、循環未反応エチレン流の抜き出し量を少な
くし、それだけエチレン損失量を低下させることができ
るが、ドライヤー、低温用の蒸留塔、比較的大容量の冷
凍機、ポンプ、リボイラー、コンデンサー等の設備費が
増大するだけでなく、冷凍機用の電力やリボイラー用の
スチーム等が必要なので、ユーテイリテイ費用も増大
し、経済性は悪化する。[0006] Known treatments for reducing the C4 + polymer in the circulating unreacted ethylene stream include cryogenic or cryogenic distillation (US Pat. No. 3,827,245;
No. 9728) and an absorption method using heavy hydrocarbons (JP-A-48-15805). According to U.S. Pat. No. 3,827,245, ethylene concentrations of 85-9
A portion of the 5% circulated unreacted ethylene stream is withdrawn and led to a dryer filled with a desiccant such as alumina to dry the gas stream and supply it to the cryogenic distillation column. The operating pressure of the cryogenic distillation column is about 290 PSIG (19.7 atm), the top temperature is about -19 ° F (-28.3 ° C), and the bottom temperature is about +
At 260 ° F. (+ 126.7 ° C.), the overhead stream is cooled to about −22 ° F. (−30 ° C.) with a condenser and refluxed to the top. The ethylene concentration of the reflux liquid is purified to 97-99%. A part of the reflux liquid is withdrawn and recycled to the reaction system as recovered ethylene. In this method, since the degree of purification of ethylene is high, the amount of circulated unreacted ethylene stream can be reduced and the amount of ethylene loss can be reduced accordingly, but a dryer, a distillation column for low temperature, a relatively large capacity refrigeration Not only does the cost of equipment such as a machine, a pump, a reboiler, and a condenser increase, but also electric power for a refrigerator and steam for a reboiler are required, so that utility costs increase and economic efficiency deteriorates.
【０００７】特公昭５１ー９７２８号の公知発明は、上
記深冷蒸留分離法の経済性を高める方法として、エチレ
ン濃度９０．０％以上の循環未反応エチレン流の一部を
抜き出し、水和物の形成による装置の閉塞を阻止するた
めに少量のエチレングリコールを添加した後、還流冷却
器を備えた低温蒸留塔に該ガスを直接供給し、蒸留塔
は、エチレンの臨界点に近い塔頂操作条件下で操作さ
れ、塔頂冷却器の頂部からエチレン濃度９５〜９７％の
ガス状回収エチレンを抜き出し、これを反応系に再循環
させるものである。この方法は、エチレンの臨界圧近く
で操作することにより、不純物の分離を容易にし、しか
も０℃程度の低温で操作できるので、米国特許第３，８
２７，２４５号の方法よりは、操作温度の高い分だけや
や経済的であるが、低温蒸留であるので、依然として冷
凍機等の設備費やユーテイリテイ費用の大幅な改善はな
されていない。[0007] The known invention of Japanese Patent Publication No. 51-9728 discloses a method for improving the economic efficiency of the above cryogenic distillation separation method by extracting a part of a circulating unreacted ethylene stream having an ethylene concentration of 90.0% or more, After addition of a small amount of ethylene glycol to prevent clogging of the apparatus due to formation of the above, the gas is directly supplied to a cryogenic distillation column equipped with a reflux condenser, and the distillation column is operated at the top near the critical point of ethylene. Under the conditions, gaseous recovered ethylene having an ethylene concentration of 95 to 97% is withdrawn from the top of the overhead cooler and is recycled to the reaction system. This method makes it easy to separate impurities by operating near the critical pressure of ethylene, and can be operated at a low temperature of about 0 ° C.
Although it is slightly more economical than the method of No. 27,245 because of the higher operating temperature, it is still a low-temperature distillation, so that the cost of equipment such as a refrigerator and the utility cost have not been significantly improved.
【０００８】特開昭４８ー１５８０５号の方法は、吸収
法で操作することで設備費やユーテイリテイ費用の改善
を目指した方法である。この方法によれば、エチレン濃
度８５〜９０％の循環未反応エチレン流の一部を抜き出
し洗浄塔の底部に導く。洗浄塔は、圧力５５〜８５気
圧、温度１５〜７５℃で操作され、該エチレンガスは水
で洗浄されて含酸素化合物を除去して上部より抜き出
し、吸収塔の底部に導かれる。吸収塔は圧力２０〜６５
気圧で操作され、軽ガス油からなる重質炭化水素を用い
て該ガス中のＣ４+ポリマーを吸収除去し、上部から実
質的にＣ４+ポリマーを含まない回収エチレンとして抜
き出し、反応系に再循環させる。Ｃ４+ポリマーを吸収
した軽ガス油は、圧力１〜８気圧で操作するストリッピ
ング塔に導かれ、エチレン及びＣ４+ポリマーを含む廃
ガスとＣ４+ポリマーを含まない軽ガス油とに分離さ
れ、Ｃ４+ポリマーを含まない軽ガス油は吸収塔に再循
環される。The method disclosed in Japanese Patent Application Laid-Open No. 48-15805 is a method aiming at improvement of equipment cost and utility cost by operating by an absorption method. According to this method, a part of the circulated unreacted ethylene stream having an ethylene concentration of 85 to 90% is withdrawn and led to the bottom of the washing tower. The washing tower is operated at a pressure of 55 to 85 atm and a temperature of 15 to 75 ° C., and the ethylene gas is washed with water to remove oxygen-containing compounds, withdrawn from the top, and led to the bottom of the absorption tower. Absorption tower pressure 20-65
It is operated at atmospheric pressure, absorbs and removes C4 + polymer in the gas using heavy hydrocarbons consisting of light gas oil, extracts from the upper part as recovered ethylene substantially free of C4 + polymer, and recycles it to the reaction system Let it. The light gas oil that has absorbed the C4 + polymer is led to a stripping tower operating at a pressure of 1 to 8 atm, and is separated into waste gas containing ethylene and C4 + polymer and light gas oil not containing C4 + polymer, Light gas oil without C4 + polymer is recycled to the absorption tower.
【０００９】この方法は蒸留法より簡便な吸収法であ
り、なるほど設備費やユーテイリテイ費用はかなり改善
されるが、ストリッピング塔の廃ガス中に含まれるエチ
レン濃度がかなり高いために、主原料であるエチレンの
回収率が悪く、深冷蒸留法或は低温蒸留法よりもエチレ
ン原単位が悪化するという欠点がある他、窒素、水素、
メタン等の不活性ガスはこの吸収法ではほとんど除去さ
れず、操業が長期に亙ると次第に反応系内に蓄積し、循
環未反応エチレン流中のエチレン純度が悪化するため生
産量や経済性が低下するという欠点もある。[0009] This method is a simpler absorption method than the distillation method. Although the equipment cost and the utility cost are considerably improved, the ethylene concentration in the waste gas of the stripping column is considerably high, so that the main raw material is used. In addition to the disadvantage that the recovery of certain ethylene is poor, the ethylene unit consumption is worse than that of cryogenic distillation or low-temperature distillation, nitrogen, hydrogen,
Inert gas, such as methane, is hardly removed by this absorption method, and gradually accumulates in the reaction system over a long period of operation, and the ethylene purity in the circulated unreacted ethylene stream deteriorates. There is also the disadvantage of doing so.
【００１０】このようにエタノールを製造する際の循環
未反応エチレン流からのエチレン回収に係る従来法は、
いずれも装置の設備費用、ユーテイリテイ費用、エチレ
ン原単位等の点で未だ充分に満足すべきものではない。[0010] As described above, the conventional method for recovering ethylene from the circulated unreacted ethylene stream in producing ethanol is as follows.
In any case, the equipment cost, the utility cost, the ethylene unit consumption, etc. are not yet fully satisfactory.
【００１１】[0011]
【発明が解決しようとする課題】この発明はこのような
事情に鑑みなされたものであり、設備費用が安価で、ユ
ーテイリテイ費用も低減でき、しかもエチレンの回収率
が高く、高純度の回収エチレンが得られるエタノールを
製造する際のエチレンの回収方法を提供することを目的
とする。SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has a low equipment cost, a reduced utility cost, a high ethylene recovery rate, and a high purity recovered ethylene. It is an object of the present invention to provide a method for recovering ethylene when producing the obtained ethanol.
【００１２】[0012]
【課題を解決するための手段】本発明者は、上記目的を
達成するために、エチレンと窒素、水素、メタン及びエ
タン等の不活性ガス並びにＣ４+ポリマーとの経済的で
効果的な分離法を化学工学的観点からまず検討した。触
媒を用いたエチレンの水和反応によりエタノールを製造
する際の循環未反応エチレン流は、圧力５０〜８０kg/c
m2Gで操作されており、膜分離法の駆動力が圧力差である
ことから、膜分離法で未反応エチレン流からエチレンを
効率よく回収できれば、未反応エチレン流の圧力を利用
できることから、電力やスチーム等のユーテイリテイ費
用を必要としないだけでなく、分離のための膜モジュー
ルを設備すれば逐次操作圧力を下げていけばよいので、
その他の高価な設備は必要がないこと、即ち、設備費用や
ユーテイリテイ費用の点から極めて安価なエチレン回収
装置になることに着目した。そこで、膜分離法に使用する
種々の高分子膜のエチレン、不活性ガス及びＣ４+ポリ
マーの膜透過性能（透過係数）について鋭意探求した結
果、ゴム状高分子膜はエチレンの透過係数が不活性ガス
類の透過係数及びＣ４+ポリマーの透過係数と異なるだ
けでなく、エチレンの透過係数は温度を変化させても変
化せず一定であるが、不活性ガス並びにＣ４+ポリマー
の透過係数は約８０℃以下の温度条件にすると大きく変
化し、エチレンと簡単に分離できることを見いだし、本
発明に到達した。In order to achieve the above object, the present inventors have developed an economical and effective method for separating ethylene from an inert gas such as nitrogen, hydrogen, methane and ethane, and a C4 + polymer. Was first studied from the viewpoint of chemical engineering. The circulated unreacted ethylene stream when producing ethanol by a hydration reaction of ethylene using a catalyst has a pressure of 50 to 80 kg / c.
Since it is operated at m 2 G and the driving force of the membrane separation method is a pressure difference, if ethylene can be efficiently recovered from the unreacted ethylene stream by the membrane separation method, the pressure of the unreacted ethylene stream can be used, Not only does it not require utility costs such as power and steam, but if a membrane module for separation is installed, the operating pressure can be lowered sequentially,
We paid attention to the fact that other expensive equipment is not required, that is, an ethylene recovery apparatus that is extremely inexpensive in terms of equipment costs and utility costs. Therefore, as a result of intensive research on the membrane permeation performance (permeability coefficient) of ethylene, inert gas and C4 + polymer of various polymer membranes used for the membrane separation method, the rubber-like polymer membrane has an inert permeability coefficient of ethylene. In addition to being different from the permeability coefficient of gases and the permeability coefficient of C4 + polymer, the permeability coefficient of ethylene remains unchanged even when the temperature is changed, but the permeability coefficient of inert gas and C4 + polymer is about 80. It has been found that when the temperature condition is lower than or equal to ° C., the temperature greatly changes and it can be easily separated from ethylene, and the present invention has been achieved.
【００１３】即ち、本発明は、触媒を用いたエチレンの
水和反応によりエタノールを製造する際に、循環未反応
エチレン流中の不純物を、ゴム状高分子膜を用いる膜分
離法によりエチレンと分離させることを特徴とする。本
発明で用いられるゴム状高分子膜は、使用状態でゴム状
弾性を有する高分子膜であり、例えばシリコンゴム、ニ
トリルゴム、ブタジエンゴム、イソプレンゴム、ブチル
ゴム、エチレンプロピレンゴム、エチレン−酢酸ビニル
共重合体或は可塑剤を多量に配合したポリ塩化ビニル、
ポリビニルアルコール等が挙げられる。特に、シリコン
ゴム膜が好適に用いられる。That is, according to the present invention, when ethanol is produced by a hydration reaction of ethylene using a catalyst, impurities in a circulating unreacted ethylene stream are separated from ethylene by a membrane separation method using a rubbery polymer membrane. It is characterized by making it. The rubber-like polymer film used in the present invention is a polymer film having rubber-like elasticity in a used state, for example, silicone rubber, nitrile rubber, butadiene rubber, isoprene rubber, butyl rubber, ethylene propylene rubber, ethylene-vinyl acetate. Polyvinyl chloride containing a large amount of polymer or plasticizer,
Polyvinyl alcohol and the like. In particular, a silicon rubber film is preferably used.
【００１４】まず、ゴム状高分子膜の各種ガスの透過性
能の測定例を示す。 （透過性能測定例１）ゴム状高分子膜の一例として、ジ
メチルシロキサンからなるシリコンゴム膜（膜厚：３０
０μｍ）を５０ｍｍφに切り取り、市販のガス膜透過実
験装置に取り付け、水素、窒素、メタン、エタン、イソ
ブタン、イソブテン、トランス−２−ブテン及びエチレ
ンのガス透過量を種々の温度及び圧力で測定し、透過係
数（cc(STP)・cm/cm2・sec・cmHg）を求めた。得られた透
過係数(Pi)から次式（１）を用いて各種ガスのエチレン
との分離係数(αi C2H4)を求めた。 αi C2H4=( Pi/ PC2H4) （１） 次表−１に、ジメチルシロキサンからなるシリコンゴム
膜の各種ガスの透過性能を示す。First, a measurement example of the permeation performance of various gases through a rubber-like polymer membrane will be described. (Permeability Measurement Example 1) As an example of the rubber-like polymer film, a silicone rubber film made of dimethylsiloxane (thickness: 30)
0 μm) was cut into 50 mmφ, attached to a commercially available gas membrane permeation test apparatus, and the gas permeation amounts of hydrogen, nitrogen, methane, ethane, isobutane, isobutene, trans-2-butene and ethylene were measured at various temperatures and pressures. The transmission coefficient (cc (STP) · cm / cm 2 · sec · cmHg) was determined. From the obtained permeability coefficient (Pi), the separation coefficient (α i C2H4 ) of various gases from ethylene was determined using the following equation (1). α i C2H4 = (P i / P C2H4 ) (1) Table 1 shows the permeation performance of various gases through a silicone rubber film made of dimethylsiloxane.
【００１５】[0015]
【表−１】 [Table-1]
【００１６】次表−２に、上記式（１）で求めたシリコ
ンゴム膜のエチレンに対する各種ガスの分離係数を示
す。The following Table 2 shows the separation coefficients of various gases with respect to ethylene of the silicon rubber film obtained by the above equation (1).
【００１７】[0017]
【表−２】 [Table-2]
【００１８】表−１の結果から、シリコンゴム膜の各種
ガスの透過係数を温度に対してプロットし図２に示す。
表−１、２及び図２から、エチレンの透過係数は、温度
を１０〜５０℃に変化させても一定であるが、エチレン
より透過しにくい水素、窒素及びメタン等の不活性ガス
は、温度を下げると益々透過しにくくなるから、分離係
数が１より更に小さくなり、温度を下げるとエチレンと
これらのガスは分離し易くなることが判明した。また、
エチレンより透過し易いエタン、イソブタン、イソブテ
ン及びトランス−２−ブテン等のガスは、温度を下げる
と益々透過し易くなるので、分離係数が１より更に大き
くなり、温度を下げるとエチレンとこれらガス類は分離
し易くなることが判明した。From the results shown in Table 1, the permeation coefficients of various gases of the silicon rubber film are plotted with respect to the temperature and are shown in FIG.
From Tables 1 and 2 and FIG. 2, the permeation coefficient of ethylene is constant even when the temperature is changed from 10 to 50 ° C., but inert gases such as hydrogen, nitrogen and methane, which are less permeable than ethylene, have a lower temperature. It has been found that the lower the temperature, the more difficult it becomes to permeate, so that the separation coefficient becomes smaller than 1, and the lower the temperature, the easier it is to separate ethylene and these gases. Also,
Gases such as ethane, isobutane, isobutene, and trans-2-butene, which are more easily permeated than ethylene, are more easily permeated when the temperature is lowered. Therefore, the separation coefficient becomes larger than 1, and when the temperature is lowered, ethylene and these gases are reduced. Was found to be easier to separate.
【００１９】（透過性能測定例２）ゴム状高分子膜の一
例として、アクリロニトリル及びブタジエンからなるニ
トリルゴム膜（膜厚：３００μｍ）を５０ｍｍφに切り
取り、測定例１と同様にして、メタン、トランス−２−
ブテン及びエチレンのガス透過量を種々の温度及び圧力
で測定し、測定例１と同様にして透過係数を求めた。次
表ー３に上記ガスの透過係数を、次表ー４に上記ガスの
エチレンに対する分離係数を示す。(Permeability Measurement Example 2) As an example of a rubber-like polymer film, a nitrile rubber film (thickness: 300 μm) made of acrylonitrile and butadiene was cut into 50 mmφ, and methane, trans- 2-
The gas permeation amounts of butene and ethylene were measured at various temperatures and pressures, and the permeation coefficients were determined in the same manner as in Measurement Example 1. The following Table 3 shows the permeation coefficient of the above gas, and the following Table 4 shows the separation coefficient of the above gas with respect to ethylene.
【００２０】[0020]
【表−３】 [Table-3]
【００２１】[0021]
【表−４】 [Table-4]
【００２２】上記結果から、ニトリルゴム膜を使用した
場合も、シリコンゴム膜を使用した場合と同様に、エチ
レンは温度を変化させても透過係数は一定であるが、メ
タンはエチレンよりニトリルゴムを透過しにくく、温度
を下げると透過係数が低下するのでエチレンと分離し易
くなり、また、トランス−２−ブテンはエチレンよりも
ニトリルゴムを透過し易く、温度を下げると透過係数が
上昇するのでエチレンと分離し易くなることがわかる。
そこで、触媒を用いたエチレン水和反応によりエタノー
ルを製造する際の、循環未反応エチレン流を、ゴム状高
分子膜を用いる膜分離法で２段で処理すると、１段目の
膜分離において、水素、窒素及びメタンはエチレンより
低温になるほどゴム状高分子膜を透過しにくいので高圧
側に蓄積し、透過側にエチレン、エタン及びＣ４+ポリ
マー等が濃縮され、そして２段目の膜分離において、エ
タン及びＣ４+ポリマー等は低温になるほどゴム状高分
子膜を透過し易いので透過側に分離され、高圧側にエチ
レンが極めて効果的に濃縮されることが判明した。From the above results, when the nitrile rubber film is used, the transmission coefficient of ethylene is constant even when the temperature is changed, as in the case of using the silicon rubber film. It is difficult to permeate, and when the temperature is lowered, the permeability coefficient is lowered, so that it is easy to separate from ethylene.In addition, trans-2-butene is easier to permeate nitrile rubber than ethylene, and when the temperature is lowered, the permeability coefficient is increased. It can be seen that it is easy to separate from
Therefore, when the circulating unreacted ethylene stream at the time of producing ethanol by the ethylene hydration reaction using a catalyst is treated in two stages by a membrane separation method using a rubbery polymer membrane, in the first stage membrane separation, Hydrogen, nitrogen and methane are harder to permeate through the rubbery polymer membrane as the temperature becomes lower than ethylene, so they accumulate on the high pressure side, and ethylene, ethane and C4 + polymer are concentrated on the permeation side. It was found that ethane, ethane, C4 + polymer, etc. permeate the rubbery polymer membrane more easily at lower temperatures and are separated on the permeate side, and ethylene is concentrated very effectively on the high pressure side.
【００２２】次に、本発明のエタノールの製造法に於け
るエチレンの回収法を、図面に基づいて説明する。図１
は、本発明の一例を示すフロー図である。触媒を用いた
エチレンの水和反応によりエタノールを製造する際の循
環未反応エチレン流の一部を公知方法により水洗した
後、ライン１から水蒸気選択透過性膜からなる膜モジュ
ールＭ１に供給する。該ガスは同伴されるエタノールを
回収するため上記のように水洗されるので、水洗の操作
条件に於ける飽和水蒸気を含有している。エチレンは低
温になると、固形の水との分子化合物（エチレン水和
物）を形成するので、減圧操作時の断熱膨張による温度
低下などの際に装置閉塞等の障害が生じる。そこで公知
方法では、ドライヤーで乾燥するか、エチレングリコー
ルを添加するか、或は加温してエチレン水和物の形成を
阻止している。Next, a method for recovering ethylene in the method for producing ethanol of the present invention will be described with reference to the drawings. FIG.
FIG. 2 is a flowchart showing an example of the present invention. A part of a circulating unreacted ethylene stream used for producing ethanol by a hydration reaction of ethylene using a catalyst is washed with water by a known method, and then supplied from a line 1 to a membrane module M1 including a water vapor selective permeable membrane. The gas is washed as described above to recover the entrained ethanol, and therefore contains saturated steam under the operating conditions of the wash. At low temperatures, ethylene forms a molecular compound (ethylene hydrate) with solid water, so that obstruction such as device blockage occurs when the temperature is reduced due to adiabatic expansion during decompression operation. Therefore, in a known method, the formation of ethylene hydrate is prevented by drying with a dryer, adding ethylene glycol, or heating.
【００２３】本発明においては、市販の水蒸気選択透過
性高分子膜、例えばポリビニルアルコール系膜、キトサ
ン系膜、ポリイミド系膜等からなる膜モジュールＭ１を
用いて、透過側（低圧側）に水蒸気を選択的にエチレン
流と分離し、ライン３から水蒸気或は水を排出させ、高
圧側の脱湿されたエチレン流をライン２から次のゴム状
高分子膜からなる膜モジュールＭ２に供給する。この脱
湿工程によりその後の操作におけるエチレン水和物の形
成は好適に阻止されるが、公知のドライヤーを用いた乾
燥法或は加温によりエチレン水和物形成の阻止方法の組
み合わせ若しくは代替も当然に本発明に包含される。膜
モジュールＭ１の高圧側の操作圧力は、３kg/cm2G以上
であればよいが、通常はその後の分離操作圧力の関係か
ら３０〜８０kg/cm2Gとするのが好ましい。透過側圧力
は、高圧側より低圧であればよいが、脱湿効果の関係から
常圧が好ましい。操作温度は、高温ほど脱湿効果がある
が、高分子膜の耐熱性から常温〜１２０℃が好ましい。In the present invention, a water vapor selectively permeable polymer membrane, for example, a membrane module M1 composed of a polyvinyl alcohol-based membrane, a chitosan-based membrane, a polyimide-based membrane, or the like is used to supply steam to the permeation side (low pressure side). It is selectively separated from the ethylene stream, steam or water is discharged from the line 3, and the dehumidified ethylene stream on the high pressure side is supplied from the line 2 to the next membrane module M2 made of a rubbery polymer membrane. Although the formation of ethylene hydrate in the subsequent operation is suitably prevented by this dehumidification step, a combination or alternative of a drying method using a known dryer or a method of preventing ethylene hydrate formation by heating is of course required. Are included in the present invention. Operating pressure of the high pressure side of the membrane module M1 may if 3 kg / cm 2 G or more, usually preferably set to 30~80kg / cm 2 G from a relationship subsequent separation operation pressure. The pressure on the permeation side may be lower than that on the high pressure side, but is preferably normal pressure in view of the dehumidification effect. The higher the operating temperature, the more effective the dehumidification effect.
【００２４】ゴム状高分子膜、好ましくはシリコンゴム
膜からなる膜モジュールＭ２で高圧側に水素、窒素及び
メタンが濃縮され、ライン４から排出される。低圧側に
エチレン、エタン及びＣ４+ポリマーを選択的に透過さ
せ、水素、窒素及びメタンを分離したエチレン流をライ
ン５から次のゴム状高分子膜からなる膜モジュールＭ３
に供給する。膜モジュールＭ２の高圧側の操作圧力は、
同様に３kg/cm2G以上であればよいが、膜モジュールＭ１
の高圧側ガス流をそのまま導けばよいので、通常は３０
〜８０kg/cm2Gとするのが好ましい。透過側圧力は、高圧
側圧力より低圧であればよいが、分離効率及び反応系の
エチレン供給用コンプレッサーの吸入圧力の関係から、
１０〜７０kg/cm2Gとするのが好ましい。操作温度は、前
記したようにゴム状高分子膜のガス透過性質から８０℃
以下であればよいが、操作性や経済性の点から０〜８０
℃が好ましい。Hydrogen, nitrogen and methane are concentrated on the high pressure side in a membrane module M 2 made of a rubber-like polymer membrane, preferably a silicone rubber membrane, and discharged from the line 4. An ethylene stream, which selectively permeates ethylene, ethane and C4 + polymer on the low pressure side and separates hydrogen, nitrogen and methane, is passed through line 5 through a membrane module M3 comprising a rubbery polymer membrane.
To supply. The operating pressure on the high pressure side of the membrane module M2 is
Similarly, the membrane module M1 may be 3 kg / cm 2 G or more.
Since the high-pressure side gas flow of may be conducted as it is,
It is preferable to set it to ８０80 kg / cm 2 G. The permeate pressure may be lower than the high pressure, but from the relationship between the separation efficiency and the suction pressure of the ethylene supply compressor of the reaction system,
It is preferably 10 to 70 kg / cm 2 G. The operating temperature is 80 ° C. due to the gas permeability of the rubbery polymer membrane as described above.
The following is acceptable, but from the viewpoint of operability and economy, it is 0 to 80.
C is preferred.
【００２５】受け入れ原料エチレンが高純度で水素、窒
素、メタン及びエタンの含有量が極めて少ない場合は、
膜モジュールＭ２での分離操作を省略し、膜モジュール
Ｍ１或は従来法で脱湿したガスをライン１０から膜モジ
ュールＭ３に導入してもよい。ゴム状高分子膜、好まし
くはシリコンゴム膜からなる膜モジュールＭ３で高圧側
にエチレンを濃縮精製させ、ライン６から回収エチレン
として反応系に戻される。低圧側に選択的に透過させた
エタン及びＣ４+ポリマーを、エチレン回収率を高める
ため、ライン７から次のゴム状高分子膜からなる膜モジ
ュールＭ４に供給する。膜モジュールＭ３の高圧側の操
作圧力は、３kg/cm2G以上であればよいが、膜モジュール
Ｍ２の透過側ガス流をそのまま導けばよいので、通常は
圧力１０〜７０kg/cm2Gで操作される。透過側圧力は高圧
側圧力より低圧であればよいが、分離効率及び反応系の
低圧エチレン回収用コンプレッサーの吸入圧力の関係か
ら、１〜３０kg/cm2Gとするのが好ましい。操作温度
は、膜モジュールＭ２と同様にゴム状高分子膜のガス透
過性質から８０℃以下であればよいが、操作性や経済性
の点で０〜８０℃が好ましい。In the case where the receiving raw material ethylene is highly pure and has extremely low contents of hydrogen, nitrogen, methane and ethane,
The separation operation in the membrane module M2 may be omitted, and the membrane module M1 or a gas dehumidified by a conventional method may be introduced from the line 10 into the membrane module M3. Ethylene is concentrated and purified on the high pressure side by a membrane module M3 made of a rubber-like polymer membrane, preferably a silicone rubber membrane, and is returned to the reaction system as recovered ethylene from the line 6. The ethane and C4 + polymer selectively permeated to the low pressure side are supplied from a line 7 to the next membrane module M4 made of a rubbery polymer membrane in order to increase the ethylene recovery. The operating pressure on the high pressure side of the membrane module M3 may be 3 kg / cm 2 G or more. However, since the gas flow on the permeate side of the membrane module M2 may be guided as it is, it is usually operated at a pressure of 10 to 70 kg / cm 2 G. Is done. The pressure on the permeation side may be lower than the pressure on the high pressure side, but is preferably 1 to 30 kg / cm 2 G in view of the separation efficiency and the suction pressure of the low-pressure ethylene recovery compressor of the reaction system. The operating temperature may be 80 ° C. or less from the gas permeation property of the rubbery polymer membrane as in the case of the membrane module M2, but is preferably 0 to 80 ° C. in terms of operability and economy.
【００２６】２段目のエチレン回収用のゴム状高分子
膜、好ましくはシリコンゴム膜からなる膜モジュールＭ
４において、ライン７から導かれたエタン、Ｃ４+ポリ
マー及び同伴してくるエチレンを含むガス流を、高圧側
圧力１〜３０kg/cm2G、透過側圧力０〜１０kg/cm2G、操
作温度８０℃以下、好ましくは０〜８０℃の条件で分離
操作する。高圧側にエチレンが濃縮精製され、ライン８
から回収エチレンとして反応系に戻される。透過側にエ
タン及びＣ４+ポリマーが更に濃縮され、ライン９から
排出される。エチレン回収率を高めるために更に逐次段
に膜モジュールを組み合わせる方法や反応系における触
媒のエチレン水和活性等の関係で循環未反応エチレン中
のエチレン純度が高い場合などでは、膜モジュールＭ４
を省略する方法も当然に本発明に包含される。また従来
の吸収法プロセスにおけるストリッピング塔の廃ガスか
ら、ゴム状高分子膜を用いた膜分離法でエチレンを回収
する組み合わせ法も本発明に包含されるのは勿論であ
る。A second-stage membrane module M made of a rubbery polymer membrane for recovering ethylene, preferably a silicone rubber membrane
At 4, the gaseous stream containing ethane, C4 + polymer and entrained ethylene from line 7 is fed with a high-pressure side pressure of 1-30 kg / cm 2 G, a permeate side pressure of 0-10 kg / cm 2 G, operating temperature The separation operation is performed at a temperature of 80 ° C or lower, preferably 0 to 80 ° C. Ethylene is concentrated and refined on the high pressure side, and line 8
Is returned to the reaction system as recovered ethylene. On the permeate side, the ethane and C4 + polymer are further concentrated and exit from line 9. In the case of a method in which the membrane modules are further combined in order to increase the ethylene recovery rate, or when the ethylene purity in the circulated unreacted ethylene is high due to the ethylene hydration activity of the catalyst in the reaction system, the membrane module M4
Is naturally included in the present invention. The present invention also encompasses a combined method of recovering ethylene from waste gas from a stripping tower in a conventional absorption process by a membrane separation method using a rubbery polymer membrane.
【００２８】[0028]
【実施例】次に、本発明の一実施例を図１を参照しなが
ら説明する。エチレン水和反応に使用した循環未反応エ
チレン流の一部を、ライン１から市販のポリイミド系水
選択透過中空糸膜からなる膜モジュールＭ１に供給し、
該エチレン流を高圧側圧力６０kg/cm2G、透過側圧力常
圧、温度７０℃の条件で乾燥させ、高圧側の乾燥ガス
（エチレン濃度８７．２％）をライン２からジメチルシ
ロキサンからなるシリコンゴム中空糸膜５００m2を有す
る膜モジュールＭ２に２７６Nm3/hで供給し、高圧側圧力
５０kg/cm2G、透過側圧力３０kg/cm2G、温度３５℃の条
件で分離させ、高圧側から不活性ガスを多く含む廃ガス
（エチレン濃度２９．３％）８．２Nm3/hをライン４か
ら排出した。Next, an embodiment of the present invention will be described with reference to FIG. A part of the circulating unreacted ethylene stream used for the ethylene hydration reaction is supplied from a line 1 to a commercially available membrane module M1 composed of a polyimide-based water-selective hollow fiber membrane,
The ethylene stream was dried under the conditions of a high-pressure side pressure of 60 kg / cm 2 G, a permeation side pressure of normal pressure, and a temperature of 70 ° C., and a high-pressure side dry gas (ethylene concentration of 87.2%) was supplied from line 2 to a silicone made of dimethylsiloxane. It is supplied to a membrane module M2 having a rubber hollow fiber membrane of 500 m 2 at 276 Nm 3 / h, separated under the conditions of a high pressure side pressure of 50 kg / cm 2 G, a permeation side pressure of 30 kg / cm 2 G and a temperature of 35 ° C. 8.2 Nm 3 / h of waste gas containing a large amount of inert gas (ethylene concentration 29.3%) was discharged from the line 4.
【００２９】透過側ガス流（エチレン濃度８９．０％）
２６７．８Nm3/hをライン５からジメチルシロキサンか
らなるシリコンゴム中空糸膜５０m2を有する膜モジュー
ルＭ３に供給し、高圧側圧力３０kg/cm2G、透過側圧力
１０kg/cm2G、温度３０℃の条件で分離させ、高圧側か
らエチレン濃度９１．７％の回収エチレンがライン６か
ら２０７．２Nm3/h 得られた。透過側ガス流（エチレン
濃度７９．５％）６０．６Nm3/hを、ライン７からジメチ
ルシロキサンからなるシリコンゴム中空糸膜５０m2を有
する膜モジュールＭ４に供給し、高圧側圧力1０kg/cm
2G、透過側圧力３kg/cm2G、温度２５℃の条件で分離さ
せ、高圧側からエチレン濃度９２．２％の回収エチレン
がライン８から３７．３Nm3/h 得られた。エタン及びＣ
４+ポリマーを多く含む透過側ガス流（エチレン濃度５
９．２％）２３．３Nm3/hをライン９から廃ガスとして
排出した。Permeate gas flow (ethylene concentration 89.0%)
267.8 Nm 3 / h is supplied from a line 5 to a membrane module M3 having a 50 m 2 silicon rubber hollow fiber membrane made of dimethylsiloxane, and a high pressure side pressure of 30 kg / cm 2 G, a permeation side pressure of 10 kg / cm 2 G, and a temperature of 30 Separation was performed under the condition of ° C., and 207.2 Nm 3 / h of recovered ethylene having an ethylene concentration of 91.7% was obtained from the line 6 from the high pressure side. A permeate-side gas flow (ethylene concentration: 79.5%) of 60.6 Nm 3 / h was supplied from a line 7 to a membrane module M4 having a 50 m 2 silicon rubber hollow fiber membrane made of dimethylsiloxane, and a high pressure side pressure of 10 kg / cm.
2 G, permeate side pressure 3kg / cm 2 G, is separated at a temperature of 25 ° C., the recovery of ethylene ethylene concentration 92.2% was obtained from a line 8 37.3 nm 3 / h from the high pressure side. Ethane and C
4 + Permeate gas stream rich in polymer (ethylene concentration 5
(9.2%) 23.3 Nm 3 / h was discharged from line 9 as waste gas.
【００３０】本発明方法のエチレン回収率は、９３．３
％で後記比較例の吸収法の回収率８９．７％よりも良好
であるので、それだけ反応系から抜き出す循環未反応エ
チレン量が少なくて済むことと、廃ガス中に不純物を高
濃度まで濃縮することで廃ガス中のエチレン濃度を低く
できるので、本発明のエチレン損失量は１６．２Nm3/h
となり、比較例のエチレン損失量３１．８Nm3/hと比較
すると、エチレン損失量は約１／２であった。また、ユ
ーテイリテイは、乾燥の際にわずかにスチームを使用し
ただけである。The ethylene recovery of the process of the present invention is 93.3.
%, Which is better than the recovery rate of the absorption method of the comparative example of 89.7% described later, so that the amount of circulated unreacted ethylene extracted from the reaction system can be reduced accordingly, and the impurities in the waste gas are concentrated to a high concentration. As a result, the ethylene concentration in the waste gas can be reduced, so that the ethylene loss of the present invention is 16.2 Nm 3 / h
In comparison with the ethylene loss amount of the comparative example of 31.8 Nm 3 / h, the ethylene loss amount was about １ ／. The utility also used only a small amount of steam during drying.
【００３１】[0031]
【比較例】エチレン水和反応に使用した循環未反応エチ
レン流（エチレン濃度８７．２％）の一部を抜き出し、
圧力２１kg/cm2G、温度３８℃で操作されている吸収塔
（塔径２８４ｍｍ×塔高７５００ｍｍ）の下段に３５
４．４Nm3/hで供給し、次のストリッピング塔から循環
される軽ガス油を、上段から３４２リットル／ｈで降ら
して主としてエチレン及びＣ４+ポリマーを吸収させ、
吸収塔塔頂からエチレン濃度８８．２％の回収エチレン
が３１４．５Nm3/hで得られた。主としてエチレン及び
Ｃ４+ポリマーを吸収した軽ガス油は、熱交換器で圧力
７kg/cm2Gのスチームで１２０℃に加熱され、次の圧力
３kg/cm2Gで操作されているストリッピング塔（塔径上
部２９８ｍｍ×塔径下部７００ｍｍ×塔高２８５０ｍ
ｍ）に供給し、ストリッピング塔塔頂から廃ガス（エチ
レン濃度７９．８％）を３９．８Nm3/hで排出した。ス
トリッピング塔塔底からポンプを用いて軽ガス油を抜き
出し、熱交換器で工業用水を使用して冷却後、吸収塔に
循環させた。この時のエチレン回収率は、８９．７％で
エチレン損失量は３１．８Nm3/hであった。[Comparative Example] A part of the circulating unreacted ethylene stream (ethylene concentration: 87.2%) used in the ethylene hydration reaction was extracted,
In the lower stage of the absorption tower (tower diameter 284 mm x tower height 7500 mm) operated at a pressure of 21 kg / cm 2 G and a temperature of 38 ° C, 35
The light gas oil supplied at 4.4 Nm 3 / h and circulated from the next stripping column is dropped at 342 liter / h from the upper stage to absorb mainly ethylene and C4 + polymer,
Recovered ethylene having an ethylene concentration of 88.2% was obtained at 314.5 Nm 3 / h from the top of the absorption tower. The light gas oil, which mainly absorbed ethylene and C4 + polymer, was heated to 120 ° C. with steam at a pressure of 7 kg / cm 2 G in a heat exchanger and then operated in a stripping column (3 kg / cm 2 G). Tower diameter upper part 298mm x tower diameter lower part 700mm x tower height 2850m
m), and a waste gas (ethylene concentration: 79.8%) was discharged from the top of the stripping tower at 39.8 Nm 3 / h. Light gas oil was withdrawn from the bottom of the stripping tower using a pump, cooled with a heat exchanger using industrial water, and circulated to the absorption tower. At this time, the ethylene recovery rate was 89.7%, and the ethylene loss amount was 31.8 Nm 3 / h.
【００３２】[0032]
【作用】膜を用いたガス分離におけるガスの透過機構は
溶解拡散機構と言われている。本発明に用いられるゴム
状高分子膜は、水素、窒素及びメタン等の不活性ガスの
溶解係数が小さいので、拡散速度が支配的となるから低
温になるほど透過しにくくなるものと考えられる。一
方、エタンやＣ４+ポリマーは、溶解係数が大きく、溶
解によりゴム状高分子が膨潤し更に溶解性が増大するほ
か、膨潤により高分子セグメント間隙が大きくなるた
め、透過分子が大きくなっても拡散阻害は生じないの
で、溶解速度が支配的となり低温程よく溶解し、透過し
易くなるものと考えられる。それに対して、エチレンは
温度変化による溶解速度変化及び拡散速度変化が結果と
して相殺されるので、透過速度が一定になっているもの
と思われる。The gas permeation mechanism in gas separation using a membrane is called a dissolution-diffusion mechanism. Since the rubber-like polymer membrane used in the present invention has a small solubility coefficient of an inert gas such as hydrogen, nitrogen and methane, the diffusion rate is dominant. On the other hand, ethane and C4 + polymers have a large solubility coefficient, and the dissolution of the rubber-like polymer swells to further increase the solubility. In addition, since the swelling increases the polymer segment gap, even if the permeating molecule becomes large, it diffuses. Since no inhibition occurs, it is considered that the dissolution rate is dominant and the dissolution is better at lower temperatures, and the permeation is easier. On the other hand, it seems that ethylene has a constant permeation rate because the change in dissolution rate and the change in diffusion rate due to temperature change are offset as a result.
【００３３】[0033]
【効果】本発明方法によれば、深冷蒸留法或は吸収法に
よる従来のエチレン回収法と比較して、膜モジュールを
設備するだけでよく、循環未反応エチレン流の圧力によ
り膜分離法の駆動力とすることができるので、設備費が
深冷蒸留法の１／５〜１／３程度、吸収法の１／２〜２
／３程度で済むと共に、電力は一切使用せず、スチーム
は脱湿工程で僅かに加温するだけであるから、ランニン
グコストは殆ど必要としないほか、エチレン回収率が吸
収法より優れており、エチレン損失量が少ないので、エ
タノール製造に於けるエチレン原単位を向上させ得るこ
とから、それだけ安価にエタノールを製造できる等、従
来のこの種エチレン回収法と比べて著しく顕著な効果を
奏する。According to the method of the present invention, as compared with the conventional ethylene recovery method using a cryogenic distillation method or an absorption method, it is only necessary to install a membrane module, and the pressure of the circulating unreacted ethylene stream is used for the membrane separation method. Since the driving force can be used, the equipment cost is about 1/5 to 1/3 of the cryogenic distillation method and 1/2 to 2 of the absorption method.
In addition to using only about / 3, no electricity is used, and steam is only slightly heated in the dehumidification process, so running costs are hardly needed, and ethylene recovery rate is superior to the absorption method. Since the amount of ethylene loss is small, it is possible to improve the unit consumption of ethylene in the production of ethanol. Therefore, it is possible to produce ethanol at a lower cost.
【００３４】[0034]
【図１】本発明の膜分離プロセスフロー概念図である。FIG. 1 is a conceptual diagram of a membrane separation process flow of the present invention.
【図２】シリコンゴム膜の各種ガスの透過係数を温度に
対してプロットしたグラフである。FIG. 2 is a graph in which the transmission coefficients of various gases of a silicon rubber film are plotted against temperature.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 // Ｃ０７Ｂ 61/00 ３００ Ｃ０７Ｂ 61/00 ３００ ──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. 6 Identification number Agency reference number FI Technical display location // C07B 61/00 300 C07B 61/00 300
Claims (3)
タノールを製造する際に、循環未反応エチレン流中の不
純物を、ゴム状高分子膜を用いる膜分離法によりエチレ
ンと分離させることを特徴とするエチレンの回収方法。When producing ethanol by a hydration reaction of ethylene using a catalyst, impurities in a circulating unreacted ethylene stream are separated from ethylene by a membrane separation method using a rubbery polymer membrane. Ethylene recovery method.
ある請求項１に記載のエチレンの回収方法。2. The method for recovering ethylene according to claim 1, wherein the rubbery polymer film is a silicon rubber film.
請求項１若しくは２に記載のエチレンの回収方法。3. The method for recovering ethylene according to claim 1, wherein the membrane separation operation temperature is 0 to 80 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5172057A JP2618589B2 (en) | 1993-06-21 | 1993-06-21 | Ethylene recovery method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5172057A JP2618589B2 (en) | 1993-06-21 | 1993-06-21 | Ethylene recovery method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0710788A JPH0710788A (en) | 1995-01-13 |
| JP2618589B2 true JP2618589B2 (en) | 1997-06-11 |
Family
ID=15934740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5172057A Expired - Fee Related JP2618589B2 (en) | 1993-06-21 | 1993-06-21 | Ethylene recovery method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2618589B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100315896B1 (en) * | 1999-12-30 | 2001-12-24 | 박호군 | Facilitated Transport Membranes Using Solid State Polymer Electrolytes |
| KR100315894B1 (en) * | 1999-12-30 | 2001-12-24 | 박호군 | Solid State Facilitated Transport Membranes for Alkene Separation Using Polymer Electrolytes |
| JP2005225968A (en) * | 2004-02-12 | 2005-08-25 | Nippon Zeon Co Ltd | Method for stripping volatile organic material, and method for producing polymer toner |
| US9421534B2 (en) | 2006-12-28 | 2016-08-23 | Mitsubishi Chemical Corporation | Production method of α-olefin low polymer |
| FR3003564B1 (en) * | 2013-03-19 | 2015-03-06 | Arkema France | METATHESIS METHOD COMPRISING THE EXTRACTION OF ETHYLENE FORMED USING A MEMBRANE |
| JP6259375B2 (en) * | 2014-08-13 | 2018-01-10 | Ｊｘｔｇエネルギー株式会社 | Hydrogen and olefin purification system |
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1993
- 1993-06-21 JP JP5172057A patent/JP2618589B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
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| JPH0710788A (en) | 1995-01-13 |
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