JP2889346B2 - Method for recovering dimethylformamide - Google Patents
Method for recovering dimethylformamideInfo
- Publication number
- JP2889346B2 JP2889346B2 JP25594390A JP25594390A JP2889346B2 JP 2889346 B2 JP2889346 B2 JP 2889346B2 JP 25594390 A JP25594390 A JP 25594390A JP 25594390 A JP25594390 A JP 25594390A JP 2889346 B2 JP2889346 B2 JP 2889346B2
- Authority
- JP
- Japan
- Prior art keywords
- dimethylformamide
- water
- concentration
- solution
- reverse osmosis
- 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 - Lifetime
Links
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、水を溶媒とするジメチルホルムアミドの希
薄溶液からジメチルホルムアミドを回収する方法に関す
るものである。Description: TECHNICAL FIELD The present invention relates to a method for recovering dimethylformamide from a dilute solution of dimethylformamide using water as a solvent.
（従来の技術） 水を溶媒とする希薄溶液から有価物を回収する方法と
して、逆浸透分離膜法がある。又、水と有価物との間に
相当の沸点差があれば、蒸留法も適用できる。(Related Art) As a method of recovering valuable resources from a dilute solution using water as a solvent, there is a reverse osmosis separation membrane method. If there is a considerable difference in boiling point between water and valuables, a distillation method can be applied.
上記逆浸透分離膜法においては、逆浸透分離膜モジュ
ールに原液を浸透圧以上の圧力で圧送し、原液中の水を
半透膜に押し通して分離し、この分離により濃縮された
原液（濃縮液）を同モジュールの入口側に戻し、再び、
同モジュールに圧送して水の分離、溶液の濃縮を行な
い、以後、この分離、濃縮を繰返していく。In the reverse osmosis separation membrane method, a stock solution is pumped to a reverse osmosis separation membrane module at a pressure higher than the osmotic pressure, water in the stock solution is pushed through a semipermeable membrane and separated, and the stock solution concentrated by this separation (concentrated solution) ) To the entrance side of the module,
Water separation and concentration of the solution are performed by pumping to the same module, and thereafter, the separation and concentration are repeated.
又、上記蒸留法においては、塔頂からの低沸点成分に
富んだガスを凝縮し、この凝縮液の一部を塔内の最上段
に還流し、この還流液を下段に向け流下させていき、各
段の蒸気上昇管を通過する蒸気を各段において気液接触
させてその一部を液化させ、その時に放出する熱で低沸
点成分に富んだ蒸気を発生させ、この蒸気と上記液化さ
れなかった蒸気が次の上側段の蒸気上昇管に向かって上
昇し、他方、液化した高沸点成分に富んだ液が下側段に
向かって流下し、以上の現象が塔内最下段から最上段に
向かって繰り返されていき、低沸点成分ほど上部に、高
沸点成分ほど下部に集まって両成分が分離されていく。In the distillation method, a gas rich in low-boiling components is condensed from the top of the column, a part of the condensate is refluxed to the uppermost stage in the column, and the refluxed liquid is allowed to flow down to the lower stage. In each stage, the steam passing through the steam riser in each stage is brought into gas-liquid contact in each stage to liquefy a part of the steam, and the heat released at that time generates steam rich in low boiling point components, and this steam and the above-mentioned liquefied The vapor that did not rise rises toward the next upper vapor riser, while the liquefied high-boiling component-rich liquid flows down to the lower stage. The components are separated toward the lower boiling point component at the upper portion and the higher boiling point component at the lower portion.
（解決しようとする課題） しかしながら、上記の逆浸透分離膜法においては、濃
縮が進むにつれて浸透圧が増大し、この浸透圧と原液圧
力との差、即ち、逆圧が小さくなって、水の分離速度、
従って、原液の濃縮速度が低下していく。(Problems to be Solved) However, in the above reverse osmosis separation membrane method, the osmotic pressure increases as the concentration progresses, and the difference between the osmotic pressure and the stock solution pressure, that is, the reverse pressure decreases, and water is removed. Separation speed,
Therefore, the concentration rate of the stock solution decreases.
他方、上記の蒸留法の場合、水が有価物よりも低沸点
であるとき、例えば、有価物がジメチルホルムアミドや
ｎ−メチルピロリドン等である場合、水がその低沸点の
ために激しく蒸発して蒸留塔の塔頂より排出され、この
排出水の価値が上記ジメチルホルムアミドやｎ−メチル
ピロリドン等の有価物に較べて著しく低く、かつ水の蒸
発潜熱が高くて水の蒸発に要する熱エネルギーが大であ
るから、水の蒸発に費やされた大量の熱エネルギーが実
質上熱損失となってしまう。従って、上記水溶液の水濃
度が大であるほど、即ち、有価物濃度が小になるほど分
離効率が悪くなる。On the other hand, in the case of the above distillation method, when water has a lower boiling point than valuables, for example, when valuables are dimethylformamide or n-methylpyrrolidone, water evaporates violently due to its low boiling point. Discharged from the top of the distillation column, the value of this discharged water is significantly lower than valuables such as dimethylformamide and n-methylpyrrolidone, and the latent heat of evaporation of water is high, so that the heat energy required for water evaporation is large. Therefore, a large amount of heat energy used for evaporating water results in a substantial heat loss. Therefore, the higher the water concentration of the aqueous solution, that is, the lower the concentration of valuable substances, the lower the separation efficiency.
而して、逆浸透分離膜法では、原液の有価物濃度が高
くなるほど効率が低下し、蒸留法では原液の有価物濃度
が低くなるほど効率が低下し、互いに逆の関係にある。Thus, in the reverse osmosis separation membrane method, the efficiency decreases as the concentration of the valuable material in the stock solution increases, and in the distillation method, the efficiency decreases as the concentration of the valuable material in the stock solution decreases.
本発明の目的は、逆浸透膜分離法と蒸留法との協調に
より、水を溶媒とするジメチルホルムアミドの希薄水溶
液からジメチルホルムアミドを低コストで回収できる方
法を提供することにある。An object of the present invention is to provide a method capable of recovering dimethylformamide at low cost from a dilute aqueous solution of dimethylformamide using water as a solvent, in cooperation with a reverse osmosis membrane separation method and a distillation method.
（課題を解決するための手段） 本発明に係るジメチルホルムアミドの回収方法は、水
を溶媒とするジメチルホルムアミドの希薄溶液を逆浸透
膜分離法により処理して約10％のジメチルホルムアミド
濃度まで濃縮し、該濃縮液を蒸留法により濃縮してジメ
チルホルムアミドを回収することを特徴とする構成であ
る。(Means for Solving the Problems) In the method for recovering dimethylformamide according to the present invention, a dilute solution of dimethylformamide using water as a solvent is treated by a reverse osmosis membrane separation method and concentrated to a dimethylformamide concentration of about 10%. The concentrated liquid is concentrated by distillation to recover dimethylformamide.
（実施例の説明） 以下、図面により本発明の実施例を説明する。Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図面は本発明において使用する回収装置の一例を示す
説明図である。The drawing is an explanatory view showing an example of the collecting device used in the present invention.
図において、１は逆浸透分離膜モジュールであり、11
は当該モジュールの原液供給口を、12は濃縮液出口を、
13は分離水取出口をそれぞれ示している。この逆浸透分
離膜モジュールにはスパイラル型、チューブラー型等を
使用できる。２は原液タンクである。３は原液圧送ポン
プである。４はモジュール１の濃縮液出口12を原液タン
ク２に連通するリターン管である。５は蒸留塔であり、
51は加熱器を、52は原液供給口を、53は塔頂流出管を、
54は冷却器を、55は還流管を、57は缶底液取出管を、58
は冷却器をそれぞれ示している。６は原液送りポンプで
ある。In the figure, 1 is a reverse osmosis separation membrane module, 11
Is the stock solution supply port of the module, 12 is the concentrate solution outlet,
Reference numeral 13 denotes a separated water outlet. The reverse osmosis separation membrane module may be a spiral type, a tubular type, or the like. 2 is a stock solution tank. Reference numeral 3 denotes a stock solution pump. Reference numeral 4 denotes a return pipe for connecting the concentrate outlet 12 of the module 1 to the stock solution tank 2. 5 is a distillation column,
51 is a heater, 52 is a stock solution supply port, 53 is a top outlet pipe,
54 is a cooler, 55 is a reflux pipe, 57 is a bottom liquid outlet pipe, 58
Indicates a cooler. Reference numeral 6 denotes a stock solution feed pump.
本発明によりジメチルホルムアミドを有価物として回
収するジメチルホルムアミド希薄水溶液としては、ジメ
チルホルムアミド濃度10重量％以下のものが対象とされ
る。ジメチルホルムアミド濃度が10重量％以上のもので
は滲透圧が高く、当該水溶液の溶媒（水）を半透膜に通
すのに著しく高い圧力を必要とし、逆浸透膜分離モジュ
ールの運転エネルギーコスト上不利となるからである。As the dimethylformamide dilute aqueous solution for recovering dimethylformamide as a valuable resource according to the present invention, those having a dimethylformamide concentration of 10% by weight or less are targeted. When the dimethylformamide concentration is 10% by weight or more, the osmotic pressure is high, and a significantly high pressure is required to pass the solvent (water) of the aqueous solution through the semipermeable membrane, which is disadvantageous in the operation energy cost of the reverse osmosis membrane separation module. Because it becomes.
かかる希薄水溶液中のジメチルホルムアミドを本発明
により回収するには、図において、当該希薄水溶液を原
液タンク１内に入れ、高圧ポンプ３の運転により原液タ
ンク１内の希薄水溶液（原液）を逆浸透分離膜モジュー
ル１に浸透圧（ジメチルホルムアミドに対する水の浸透
圧）以上の圧力で供給する（原液送りポンプ６、蒸留塔
等５は停止させておく）。而して、モジュール１の原液
供給口11よりモジュール１の原液室に入った原液は原液
出口12に向かって流れ、その間、原液中の水のみが上記
運転圧力のために浸透圧に逆らって半透膜を通過し、こ
の水の分離により濃縮された原液（濃縮液）がモジュー
ル１の濃縮液出口12を経てリターン管４により原液タン
ク２に戻され、再び、高圧ポンプ３によりモジュール１
に圧送され、以後、この繰返しにより、原液のジメチル
ホルムアミド濃度が上昇されていき、他方、半透膜を通
過した水が取出口13から流出していく。In order to recover dimethylformamide in such a dilute aqueous solution according to the present invention, in the figure, the dilute aqueous solution is put in a stock solution tank 1, and the dilute aqueous solution (stock solution) in the stock solution tank 1 is subjected to reverse osmosis separation by operating a high-pressure pump 3. The solution is supplied to the membrane module 1 at a pressure higher than the osmotic pressure (the osmotic pressure of water with respect to dimethylformamide) (the stock solution feed pump 6, the distillation column 5, etc. are stopped). Thus, the undiluted solution that has entered the undiluted solution chamber of the module 1 from the undiluted solution supply port 11 of the module 1 flows toward the undiluted solution outlet 12, during which only the water in the undiluted solution is halfway against the osmotic pressure due to the above-mentioned operating pressure. The stock solution (concentrate) that has passed through the permeable membrane and concentrated by the separation of water is returned to the stock solution tank 2 by the return pipe 4 through the concentrate outlet 12 of the module 1, and again the module 1 by the high-pressure pump 3.
Thereafter, the repetition causes the concentration of dimethylformamide in the stock solution to increase, while the water that has passed through the semipermeable membrane flows out from the outlet 13.
上記原液の循環はジメチルホルムアミド濃度が約10重
量％になるまで続け、原液が当該濃度に達すれば、高圧
ポンプ３を停止してモジュール１の運転を停止する。次
いで、圧送ポンプ６を駆動すると共に蒸留塔５を駆動
し、上記約10重量％に濃縮したジメチルホルムアミド含
有水溶液を蒸留処理する。上記ジメチルホルムアミドは
水よりも高沸点物であり、低沸点成分である水の高純度
液を塔頂液として取り出し、高沸点成分であるジメチル
ホルムアミドの高純度液を缶底液として取り出し、その
蒸留条件は缶底液のジメチルホルムアミド濃度を90重量
％とするように設定する。The circulation of the stock solution is continued until the dimethylformamide concentration reaches about 10% by weight. When the stock solution reaches the concentration, the high-pressure pump 3 is stopped and the operation of the module 1 is stopped. Next, the pump 6 and the distillation column 5 are driven to distill the aqueous solution containing dimethylformamide concentrated to about 10% by weight. The above-mentioned dimethylformamide is a substance having a higher boiling point than water, and a high-purity liquid of water having a low boiling point is taken out as a top liquid, a high-purity liquid of dimethylformamide having a high boiling point is taken out as a bottom liquid, and its distillation is carried out. The conditions are set so that the dimethylformamide concentration of the bottom of the can is 90% by weight.
上記の通り、本発明においては、逆浸透分離膜モジュ
ールによるジメチルホルムアミドの濃縮処理を約10重量
％にとどめているから、この濃縮処理中での浸透圧の増
大を充分に抑制でき、ジメチルホルムアミドの濃縮、水
の分離を効率よく行ない得る。又、水溶液の蒸留処理に
おいて、水の蒸発に費やされる熱エネルギーは熱損失と
なるが、逆浸透分離膜モジュールによって水の濃度を低
下させたうえで蒸留処理しているから、それだけ水の蒸
発に要する熱エネルギーを少量にでき、従って、それだ
け熱エネルギー損失を少なくできる。ジメチルホルムア
ミドの希薄水溶液からジメチルホルムアミドを低エネル
ギーで回収でき、このことは次の試験例からも確認でき
る。As described above, in the present invention, since the concentration treatment of dimethylformamide by the reverse osmosis separation membrane module is limited to about 10% by weight, the increase in osmotic pressure during this concentration treatment can be sufficiently suppressed, and Concentration and separation of water can be performed efficiently. In addition, in the distillation treatment of the aqueous solution, the heat energy consumed for water evaporation is a heat loss, but since the distillation treatment is performed after the concentration of water is reduced by the reverse osmosis separation membrane module, the amount of heat lost to the evaporation of water. The required heat energy can be reduced and therefore the heat energy loss can be reduced accordingly. Dimethylformamide can be recovered from a dilute aqueous solution of dimethylformamide with low energy, which can be confirmed from the following test examples.
（試験結果） 芳香族ポリアミド系の膜面積８m2の半透膜を用いた逆
浸透分離膜モジュールにより、ジメチルホルムアミド濃
度1.4重量％の希薄水溶液5000kgを処理して、ジメチル
ホルムアミド濃度9.5重量％の水溶液470kgを得、これを
蒸留処理して99.88重量％のジメチルホルムアミド溶液4
3.1kgを得た。使用した熱エネルギーは合計349500kcal
であり、ジメチルホルムアミド溶液1kgを得るのに要し
た熱エネルギーは8118kcalであった。(Test result) A 5000 kg dilute aqueous solution having a dimethylformamide concentration of 1.4% by weight was treated with a reverse osmosis separation membrane module using an aromatic polyamide-based semipermeable membrane having a membrane area of 8 m 2 to obtain an aqueous solution having a dimethylformamide concentration of 9.5% by weight. 470 kg was obtained, which was subjected to a distillation treatment to obtain a 99.88% by weight dimethylformamide solution 4
3.1 kg was obtained. Total thermal energy used is 349500kcal
And the thermal energy required to obtain 1 kg of the dimethylformamide solution was 8118 kcal.
これに対して、ジメチルホルムアミド濃度1.4重量％
の希薄水溶液5000kgを蒸留のみにより処理して99.85重
量％のジメチルホルムアミド溶液67.6kgを得た。この場
合に要した総熱エネルギーは3812000kcalであり、ジメ
チルホルムアミド溶液1kgを得るのに要した熱エネルギ
ーは56200kcalであった。In contrast, a dimethylformamide concentration of 1.4% by weight
5000 kg of a dilute aqueous solution was treated only by distillation to obtain 67.6 kg of a 99.85% by weight dimethylformamide solution. The total heat energy required in this case was 3812000 kcal, and the heat energy required to obtain 1 kg of the dimethylformamide solution was 56200 kcal.
（発明の効果） 本発明によれば、ジメチルホルムアミドの希薄水溶液
からジメチルホルムアミドを有価物として回収する場
合、逆浸透分離膜モジュールでは有価物濃度の増大に伴
い分離性能が浸透圧との関係から低下し、他方、蒸留法
では、水が非有価物質であり、有価物濃度が低くなるほ
ど、従って、水濃度が高くなるほど水の大なる蒸発潜熱
のために熱損失が大となることを勘案して逆浸透分離膜
法と蒸留法とを併用し、逆浸透分離膜法によって10重量
％の濃度域を、蒸留法によってそれ以上から最終濃度域
をそれぞれ処理しているから、ジメチルホルムアミドの
希薄水溶液からジメチルホルムアミドを効率よく、低熱
エネルギーコストで回収することが可能となる。(Effect of the Invention) According to the present invention, when dimethylformamide is recovered as a valuable resource from a dilute aqueous solution of dimethylformamide, the separation performance of the reverse osmosis separation membrane module decreases from the relationship with the osmotic pressure as the concentration of the valuable component increases. On the other hand, in the distillation method, considering that water is a non-valuable substance, the lower the value of the valuable substance, and thus the higher the water concentration, the greater the heat loss due to the large latent heat of evaporation of water. The reverse osmosis separation membrane method and the distillation method are used together, and the concentration range of 10% by weight is processed by the reverse osmosis separation membrane method, and the final concentration range is further processed by the distillation method. Dimethylformamide can be efficiently recovered at low heat energy cost.
図面は本発明において使用する有価物の回収装置を示す
説明図である。 １…逆浸透分離膜モジュール、２…原液タンク、３…高
圧ポンプ、４…リターン管、５…蒸留塔、６…送りポン
プ。The drawing is an explanatory view showing a valuable resource recovery device used in the present invention. DESCRIPTION OF SYMBOLS 1 ... Reverse osmosis separation membrane module, 2 ... Stock solution tank, 3 ... High pressure pump, 4 ... Return pipe, 5 ... Distillation tower, 6 ... Feed pump.
フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) B01D 61/12 B01D 3/00 Continuation of the front page (58) Field surveyed (Int.Cl. 6 , DB name) B01D 61/12 B01D 3/00
Claims (1)
薄溶液を逆浸透膜分離法により処理して約10重量％のジ
メチルホルムアミド濃度まで濃縮し、該濃縮液を蒸留法
により濃縮してジメチルホルムアミドを回収することを
特徴とするジメチルホルムアミドの回収方法。1. A dilute solution of dimethylformamide using water as a solvent is treated by a reverse osmosis membrane separation method and concentrated to a dimethylformamide concentration of about 10% by weight, and the concentrated liquid is concentrated by a distillation method to remove dimethylformamide. A method for recovering dimethylformamide, which comprises recovering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25594390A JP2889346B2 (en) | 1990-09-25 | 1990-09-25 | Method for recovering dimethylformamide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25594390A JP2889346B2 (en) | 1990-09-25 | 1990-09-25 | Method for recovering dimethylformamide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04135627A JPH04135627A (en) | 1992-05-11 |
| JP2889346B2 true JP2889346B2 (en) | 1999-05-10 |
Family
ID=17285734
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25594390A Expired - Lifetime JP2889346B2 (en) | 1990-09-25 | 1990-09-25 | Method for recovering dimethylformamide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2889346B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024203309A1 (en) * | 2023-03-27 | 2024-10-03 | 日東電工株式会社 | Concentration system for organic solvent-containing water and concentration method for organic solvent-containing water |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5551628B2 (en) * | 2011-01-26 | 2014-07-16 | 株式会社神鋼環境ソリューション | Method and apparatus for treating wastewater containing organic chemicals |
| WO2020085432A1 (en) * | 2018-10-25 | 2020-04-30 | 木村化工機株式会社 | Solvent recovery system |
| JP6682053B1 (en) * | 2018-10-25 | 2020-04-15 | 木村化工機株式会社 | Solvent recovery system |
| CN111100027A (en) * | 2018-10-25 | 2020-05-05 | 中国石油化工股份有限公司 | Method for recovering N, N-dimethylacetamide |
-
1990
- 1990-09-25 JP JP25594390A patent/JP2889346B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024203309A1 (en) * | 2023-03-27 | 2024-10-03 | 日東電工株式会社 | Concentration system for organic solvent-containing water and concentration method for organic solvent-containing water |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04135627A (en) | 1992-05-11 |
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