JP4593264B2

JP4593264B2 - N-methyl-2-pyrrolidone recovery device and recovery method thereof

Info

Publication number: JP4593264B2
Application number: JP2004373056A
Authority: JP
Inventors: 薫亀山; 永一廣瀬; 淳白石
Original assignee: Mitsubishi Chemical Engineering Corp
Current assignee: Mitsubishi Chemical Engineering Corp
Priority date: 2004-01-30
Filing date: 2004-12-24
Publication date: 2010-12-08
Anticipated expiration: 2024-12-24
Also published as: JP2005238220A

Description

この発明は、Ｎ−メチル−２−ピロリドン回収装置に関する。 The present invention relates to an N-methyl-2-pyrrolidone recovery apparatus.

リチウムイオン電池、ポリマー電池等の電極を製造する際、溶剤や分散剤として、Ｎ−メチル−２−ピロリドンが使用される場合がある。このＮ−メチル−２−ピロリドンは、使用後、系の排ガスに同伴されて排出される。この排ガスについては、環境上の問題から、Ｎ−メチル−２−ピロリドンを取り除く必要がある。また、このＮ−メチル−２−ピロリドンを回収することにより、溶剤や分散剤として再利用することができる。 When manufacturing electrodes such as lithium ion batteries and polymer batteries, N-methyl-2-pyrrolidone may be used as a solvent or a dispersant. This N-methyl-2-pyrrolidone is discharged after being used along with the exhaust gas of the system. For this exhaust gas, it is necessary to remove N-methyl-2-pyrrolidone due to environmental problems. Further, by recovering this N-methyl-2-pyrrolidone, it can be reused as a solvent or a dispersant.

上記のＮ−メチル−２−ピロリドンの回収方法としては、上記排ガスを冷却して分離する方法、上記排ガスを水に通して、Ｎ−メチル−２−ピロリドンを水に溶解させる方法、吸着剤を用いて吸着回収する方法等があげられる。 As a method for recovering the N-methyl-2-pyrrolidone, a method for cooling and separating the exhaust gas, a method for passing the exhaust gas through water and dissolving N-methyl-2-pyrrolidone in water, and an adsorbent are used. And a method of using them for adsorption recovery.

しかし、上記のいずれの方法でも、処理された排ガス中に残存するＮ−メチル−２−ピロリドンの量が多くなる傾向がある。また、排ガス中に残存するＮ−メチル−２−ピロリドンの量をより減らすようにすると、排ガス温度のさらなる低下や、排ガスと水との接触時間のさらなる増加、及び入り口部のＮＭＰ濃度の低下が必要である。よって、いずれの場合も、ＮＭＰ除去効率の点から、不満足である。 However, in any of the above methods, the amount of N-methyl-2-pyrrolidone remaining in the treated exhaust gas tends to increase. Further, when the amount of N-methyl-2-pyrrolidone remaining in the exhaust gas is further reduced, the exhaust gas temperature is further decreased, the contact time between the exhaust gas and water is further increased, and the NMP concentration at the inlet is decreased. is necessary. Therefore, in either case, it is unsatisfactory from the point of NMP removal efficiency.

そこで、この発明は、効率よく、排ガス中のＮ−メチル−２−ピロリドンを高濃度で回収し、この排ガス中の残存Ｎ−メチル−２−ピロリドン量をより低くすることを目的とする。 Accordingly, an object of the present invention is to efficiently recover N-methyl-2-pyrrolidone in exhaust gas at a high concentration and to further reduce the amount of residual N-methyl-2-pyrrolidone in the exhaust gas.

この発明は、Ｎ−メチル−２−ピロリドンを同伴するガス、及び水又は水系液をそれぞれ流して、両者を接触させることにより、Ｎ−メチル−２−ピロリドンを上記水に吸収させる複数の吸収部を有し、この吸収部には充填物が充填され、この吸収部を直列に配した、Ｎ−メチル−２−ピロリドン回収装置を用いることにより、上記課題を解決したのである。 The present invention provides a plurality of absorbers that absorb N-methyl-2-pyrrolidone in the water by flowing a gas accompanied by N-methyl-2-pyrrolidone and water or an aqueous liquid, and bringing them into contact with each other. This problem has been solved by using an N-methyl-2-pyrrolidone recovery apparatus in which the absorption part is filled with a filler and the absorption part is arranged in series.

Ｎ−メチル−２−ピロリドンを同伴するガス、及び水又は水系液を、充填物を有する吸収部を通して流すことにより、両者の接触の程度を増加させることができる。これにより、効率よく、排ガス中のＮ−メチル−２−ピロリドンを回収し、かつ、この排ガス中の残存Ｎ−メチル−２−ピロリドン量をより低くすることができる。 By flowing the gas accompanied by N-methyl-2-pyrrolidone and water or an aqueous liquid through the absorption part having a filler, the degree of contact between the two can be increased. Thereby, N-methyl-2-pyrrolidone in the exhaust gas can be efficiently recovered, and the amount of remaining N-methyl-2-pyrrolidone in the exhaust gas can be further reduced.

この発明にかかるＮ−メチル−２−ピロリドン回収装置は、Ｎ−メチル−２−ピロリドン（以下、「ＮＭＰ」と略する。）を同伴するガス（以下、「同伴ガス」と称する。）、及び水又は水系液（以下、「水系液等」と称する。）をそれぞれ流して、両者を接触させることにより、ＮＭＰを上記水に吸収させる複数の吸収部を有する装置である。 The N-methyl-2-pyrrolidone recovery apparatus according to the present invention includes a gas accompanying N-methyl-2-pyrrolidone (hereinafter abbreviated as “NMP”) (hereinafter referred to as “entrained gas”), and It is an apparatus having a plurality of absorbing parts that absorb NMP into the water by flowing water or an aqueous liquid (hereinafter referred to as “aqueous liquid or the like”) and bringing them into contact with each other.

上記同伴ガスは、リチウムイオン電池、ポリマー電池等の電極の製造工程等で使用されるＮＭＰを加熱して、これを逸散させる際に空気等のガスに同伴させたガスである。また、上記水系液等中の水系液とは、水にＮＭＰを含有させた液をいう。 The entrained gas is a gas entrained in a gas such as air when NMP used in the manufacturing process of an electrode such as a lithium ion battery or a polymer battery is heated and diffused. The aqueous liquid in the aqueous liquid or the like refers to a liquid containing NMP in water.

この発明にかかるＮＭＰ回収装置に使用される上記同伴ガスの温度は、５０〜１４０℃がよく、６０〜１２０℃が好ましい。この温度範囲のものを使用することにより、上記ＮＭＰ回収装置において、上記同伴ガス中の水分を蒸発又は揮散させることができ、回収ＮＭＰの濃度をより向上させることができる。５０℃より低いと、上記の効果を得ることができず、回収ＮＭＰの濃度の向上が不十分となる場合がある。一方、１４０℃より高くてもよいが、上記同伴ガスの温度として、１４０℃より高い場合が少ない。 The temperature of the entrained gas used in the NMP recovery apparatus according to the present invention is preferably 50 to 140 ° C, and preferably 60 to 120 ° C. By using the thing of this temperature range, in the said NMP collection | recovery apparatus, the water | moisture content in the said accompanying gas can be evaporated or volatilized, and the density | concentration of collection | recovery NMP can be improved more. When the temperature is lower than 50 ° C., the above effect cannot be obtained, and the concentration of recovered NMP may not be improved sufficiently. On the other hand, although it may be higher than 140 ° C., the temperature of the entrained gas is rarely higher than 140 ° C.

また、上記同伴ガスの圧力は、大気圧（１ａｔｍ）程度が好ましい。圧力を高くすると、同伴ガスブロアーの動力が増える。また、圧力を大気圧より小さくする意味はない。具体的には、無弁の排風配管を通じて大気に排出されるので、各部の圧力損失に相当する圧力が自然である。 The pressure of the entrained gas is preferably about atmospheric pressure (1 atm). Increasing the pressure increases the power of the entrained gas blower. Also, there is no point in reducing the pressure below atmospheric pressure. Specifically, since it is discharged to the atmosphere through a valveless exhaust pipe, the pressure corresponding to the pressure loss of each part is natural.

さらに、上記同伴ガスに含まれる水分量は、不飽和状態の水分量が好ましい。上記同伴ガスに含まれる水分量が飽和状態だと、上記ＮＭＰ回収装置において、上記同伴ガス中の水分を蒸発又は揮散させることが困難となる場合があり、回収ＮＭＰの濃度の向上が不十分となる場合がある。 Further, the amount of water contained in the entrained gas is preferably an unsaturated water amount. If the amount of water contained in the accompanying gas is saturated, it may be difficult to evaporate or volatilize the water in the accompanying gas in the NMP recovery device, and the concentration of recovered NMP is insufficiently improved. There is a case.

上記吸収部とは、上記同伴ガスと水系液等とを接触させる部分をいい、この吸収部には充填物が充填されている。これにより、吸収部内部の気液接触面積を増加させると共に、吸収部内部の空間部分を減少させ、上記同伴ガスと水系液等との接触機会をより向上させる。 The said absorption part means the part which contacts the said entrained gas, an aqueous liquid, etc., and this absorption part is filled with the filler. Thereby, while increasing the gas-liquid contact area inside an absorption part, the space part inside an absorption part is decreased, and the contact opportunity with the said accompanying gas, an aqueous liquid, etc. is improved more.

このような充填物としては、リング状、ボール状、網状のものや、網状体や多数の穴を開けた平板体を円柱状又は塔の形状に加工した規則充填物等があげられる。上記リング状、ボール状の充填物は、多数が上記吸収部内に充填される。また、上記網状の充填物は、複数枚が上記吸収部内に積層されて充填される。さらに、規則充填物は、その径や高さを上記吸収部の径や高さに合わせたものが使用される。これらの中でも、上記規則充填物が、圧損をより低減することができ、好ましい。このような規則充填物としては、エムシーパック（菱化フォワード（株）製）等があげられる。 Examples of such packings include ring-shaped, ball-shaped, and net-like packings, and regular packings obtained by processing a net-like body or a flat plate having a large number of holes into a columnar or tower shape. Many of the ring-shaped and ball-shaped fillers are filled in the absorbing portion. In addition, a plurality of the net-like fillers are stacked and filled in the absorber. Furthermore, the regular packing is used in accordance with the diameter and height of the absorbing portion. Among these, the above ordered packing is preferable because it can further reduce the pressure loss. Examples of such regular packing include MC pack (manufactured by Ryoka Forward Co., Ltd.).

上記の吸収部は、複数、すなわち、少なくとも２つ有することが必要で、かつ、直列に配することが必要である。吸収部内の充填物の高さを高くして、吸収部を１つとした場合、上記同伴ガスからＮＭＰを回収し、同伴ガス中のＮＭＰ残量を低減させるために、水系液中のＮＭＰ濃度を上げることが困難となる傾向がある。 It is necessary to have a plurality of the absorbing parts, that is, at least two of the absorbing parts, and it is necessary to arrange them in series. When the height of the packing in the absorption part is increased and the number of absorption parts is one, NMP is recovered from the accompanying gas and the NMP concentration in the aqueous liquid is reduced in order to reduce the remaining amount of NMP in the accompanying gas. It tends to be difficult to raise.

また、上記の複数の吸収部を直列に配するのは、同伴ガスと水系液等を向流又は並流に流すことにより、同伴ガス中のＮＭＰの、水系液への移行をより効率的に行うためである。 In addition, the above-described plurality of absorption parts are arranged in series because the entrained gas and the aqueous liquid or the like are caused to flow counter-currently or in a parallel flow so that the NMP in the accompanying gas is more efficiently transferred to the aqueous liquid. To do.

この発明にかかるＮＭＰ回収装置によりＮＭＰを回収された後の同伴ガス中のＮＭＰ量は、１００ｐｐｍ以下が好ましく、２０ｐｐｍ以下がより好ましく、５ｐｐｍ以下がさらに好ましい。１００ｐｐｍより多量のＮＭＰを含有すると、排ガスにＮＭＰ臭が残る問題がある。 The amount of NMP in the entrained gas after NMP is recovered by the NMP recovery apparatus according to the present invention is preferably 100 ppm or less, more preferably 20 ppm or less, and even more preferably 5 ppm or less. When a large amount of NMP is contained more than 100 ppm, there is a problem that an NMP odor remains in the exhaust gas.

次に、この発明にかかるＮＭＰ回収装置の例を、図１〜２を用いて説明する。
図１に示すＮＭＰ回収装置１１ａは、３つの吸収部１２（１２ａ、１２ｂ、１２ｃ）を、１つの吸収塔１３ａ内に上下方向に直列に配したものであり、その内部には、上記充填物が充填される。なお、図１においては、吸収部を３つ記載したが、ＮＭＰの回収効率の点で、少なくとも２つの吸収部を有すればよく、少なくとも３つの吸収部を有すれば、よりよい。また、設ける吸収部の数の上限は、特に限定されないが、圧損の点で、５以下が好ましい。 Next, an example of the NMP recovery apparatus according to the present invention will be described with reference to FIGS.
The NMP recovery device 11a shown in FIG. 1 has three absorbers 12 (12a, 12b, 12c) arranged in series in one absorption tower 13a in the vertical direction. Is filled. In FIG. 1, three absorption units are described. However, in view of NMP recovery efficiency, it is sufficient to have at least two absorption units, and it is better to have at least three absorption units. Moreover, the upper limit of the number of absorption parts to be provided is not particularly limited, but is preferably 5 or less in terms of pressure loss.

さらに、最下段の吸収部１２ａの下方には、液貯蔵部１４が設けられる。
また、２つの吸収部（１２ａと１２ｂ、又は１２ｂと１２ｃ）の境界部には、集液装置１５が設けられる。 Further, a liquid storage unit 14 is provided below the lowermost absorption unit 12a.
Moreover, the liquid collection apparatus 15 is provided in the boundary part of two absorption parts (12a and 12b or 12b and 12c).

上記集液装置１５は、図２（ａ）（ｂ）に示すように、上記吸収塔内壁１６の周縁部に液溜め部１７が設けられ、また、この液溜め部１７以外の部分を開放して開口部１８が形成される。この開口部１８の上方には、上方から落下する水又は水系液を上記液溜め部１７に送る送り板１９が設けられる。図２に示した送り板１９は、断面がＶ字状で、液溜め部１７と開口部１８との境界壁２１上で支持され、上方から落下してきた水系液等が送り板１９のＶ字状の溝に落ち、液溜め部１７に送られる。なお、この発明で使用される送り板１９の形状、構成等は、上方から落下してきた水系液等を液溜め部１７に送ることができれば、特に限定されない。 As shown in FIGS. 2 (a) and 2 (b), the liquid collecting device 15 is provided with a liquid reservoir portion 17 at the peripheral edge of the absorption tower inner wall 16, and the portions other than the liquid reservoir portion 17 are opened. Thus, the opening 18 is formed. Above the opening 18 is provided a feed plate 19 for sending water or an aqueous liquid falling from above to the liquid reservoir 17. The feed plate 19 shown in FIG. 2 has a V-shaped cross section and is supported on the boundary wall 21 between the liquid reservoir portion 17 and the opening 18, and the aqueous liquid or the like that has dropped from above is V-shaped on the feed plate 19. It falls into a groove and is sent to the liquid reservoir 17. The shape, configuration, and the like of the feed plate 19 used in the present invention are not particularly limited as long as the aqueous liquid that has dropped from above can be sent to the liquid reservoir 17.

上記の液溜め部１７に溜まった水系液等は、上記液溜め部１７から溢れると、上記開口部１８から上記吸収塔１３ａの下方に落下する。具体的には、開口部１８の下方の集液部２２を経由して、その下方に設けられた受け部２３に集められ、スプレー装置２４（図１参照）から、下方の吸収部１２に送られる。 When the aqueous liquid or the like stored in the liquid reservoir 17 overflows from the liquid reservoir 17, it falls from the opening 18 to below the absorption tower 13 a. Specifically, the liquid is collected in a receiving portion 23 provided below the liquid collecting portion 22 below the opening 18 and sent from the spray device 24 (see FIG. 1) to the absorbing portion 12 below. It is done.

上記吸収塔１３ａには、図１に示すように、上記液貯蔵部１４内の水系液等の一部、及び上記液溜め部１７内の水系液等の一部又は全部をその直上にある吸収部１２に送る送液配管２５（２５ａ、２５ｂ、２５ｃ）が設けられる。この送液配管２５には、それぞれ送液ポンプ２６が設けられ、上記液貯蔵部１４内の水系液等や上記液溜め部１７内の水系液等をその直上にある吸収部１２、特にその吸収部１２内の充填物の上方、具体的には、その吸収部１２内の充填物の直上にある集液装置１５の集液部２２に送ることができる。これにより、上記液貯蔵部１４や液溜め部１７と、その直上にある吸収部１２との間で、水系液等を循環させることができる。 As shown in FIG. 1, the absorption tower 13 a absorbs a part of the aqueous liquid in the liquid storage unit 14 and a part or all of the aqueous liquid in the liquid reservoir 17 directly above it. A liquid feeding pipe 25 (25a, 25b, 25c) to be sent to the section 12 is provided. Each of the liquid supply pipes 25 is provided with a liquid supply pump 26 for absorbing the water-based liquid in the liquid storage unit 14 and the water-based liquid in the liquid reservoir 17, in particular the absorption unit 12. It can be sent to the liquid collecting part 22 of the liquid collecting device 15 above the filling in the part 12, specifically, directly above the filling in the absorption part 12. Thereby, an aqueous liquid etc. can be circulated between the said liquid storage part 14 or the liquid reservoir part 17, and the absorption part 12 on it.

また、液貯蔵部１４からでる送液配管２５ａには、上記液貯蔵部１４内の水系液等の一部を、外部に取り出す回収配管２７が設けられ、この回収配管２７から、ＮＭＰ吸収液を回収することができる。 In addition, the liquid delivery pipe 25 a that comes out from the liquid storage section 14 is provided with a recovery pipe 27 that extracts a part of the aqueous liquid in the liquid storage section 14 to the outside. From this recovery pipe 27, the NMP absorption liquid is supplied. It can be recovered.

さらに、上記吸収塔１３ａの最上段にある吸収部１２ｃの下の液溜め部１７の水系液等を、この吸収部に送る配管、すなわち、吸収部１２ｃに水系液等を送る送液配管２５ｃには、必要に応じて、水供給配管２８が設けられる。この水供給配管２８より水を供給することにより、排ガスと共に吸収塔１３ａから出て行く水を補給することができる。このとき使用される水としては、特に限定されないが、純水や蒸留水を用いると、この発明にかかかるＮＭＰ回収の次に行われる、ＮＭＰ精製工程で水垢（スケール）が発生しないので好ましい。 Further, a pipe for sending the aqueous liquid or the like in the liquid reservoir 17 below the absorption part 12c at the uppermost stage of the absorption tower 13a to the absorption part, that is, a liquid supply pipe 25c for sending the aqueous liquid or the like to the absorption part 12c. The water supply pipe 28 is provided as needed. By supplying water from the water supply pipe 28, the water exiting the absorption tower 13a together with the exhaust gas can be replenished. The water used at this time is not particularly limited, but it is preferable to use pure water or distilled water because scale (scale) is not generated in the NMP purification step performed after the NMP recovery according to the present invention.

さらにまた、排ガスと共に吸収塔１３ａから出て行く水を極力減らし、水供給配管２８から供給する補給水量を減少させるために、送液配管２５ｃの途中に、この水系液等を冷却する熱交換器２９を配することができる。これにより、吸収部１２ｃの上部にあるスプレー装置２４ｃから降らせる水系液等の温度をより低下させることができ、吸収部１２ｃを通って上昇する排ガスの温度をより低下させることができ、排ガス中の水分を回収し、排ガス中の水分量をより減らすことができる。 Furthermore, in order to reduce the amount of water leaving the absorption tower 13a together with the exhaust gas as much as possible and reduce the amount of makeup water supplied from the water supply pipe 28, a heat exchanger that cools this aqueous liquid or the like in the middle of the liquid supply pipe 25c. 29 can be arranged. Thereby, the temperature of the water-based liquid etc. which can fall from the spray apparatus 24c in the upper part of the absorption part 12c can be lowered | hung more, the temperature of the exhaust gas which raises through the absorption part 12c can be lowered more, and in exhaust gas Moisture can be recovered and the amount of moisture in the exhaust gas can be further reduced.

次に、図１に示すＮＭＰ回収装置１１ａを用いたＮＭＰの回収方法について説明する。
まず、ＮＭＰ回収装置１１ａの液貯蔵部１４内の水系液等の一部、及び各液溜め部１７内の水系液等Ａの一部又は全部を、その直上にある吸収部１２に送って、その水系液等Ａをそれぞれの吸収部１２の充填物の中を上方から下方に向かって流す。 Next, an NMP recovery method using the NMP recovery apparatus 11a shown in FIG. 1 will be described.
First, a part of the aqueous liquid in the liquid storage part 14 of the NMP recovery device 11a and a part or the whole of the aqueous liquid A etc. in each liquid reservoir 17 are sent to the absorption part 12 immediately above it, The aqueous liquid A or the like is caused to flow from the upper side to the lower side in the packing of each absorption unit 12.

さらに、最下段の吸収部１２ａと液貯蔵部１４との間に、上記同伴ガスＢを導入し、この同伴ガスＢを上記Ｎ−メチル−２−ピロリドン回収装置の上方に向かって流す。このため、水系液等Ａと同伴ガスＢとは向流となり、これらは、上記のそれぞれの吸収部１２内で接触する。そして、同伴ガスＢ中のＮＭＰが上記水系液等Ａに吸収される。 Further, the entrained gas B is introduced between the lowermost absorption unit 12a and the liquid storage unit 14, and the entrained gas B is caused to flow upward above the N-methyl-2-pyrrolidone recovery device. Therefore, the aqueous liquid A or the like and the entrained gas B are counter-current, and they come into contact with each other in the above-described absorption portions 12. Then, NMP in the accompanying gas B is absorbed by the aqueous liquid A or the like.

各吸収部１２を通過したガスは、分離フィルター３１を通して、排ガスＣとして、ＮＭＰ回収装置１１ａより排出される。この分離フィルター３１は、排ガスＣ中の水系液等を最後に分離するためのフィルターであり、３μｍ以上の液滴を分離できるものであればよい。このような例として、東京特殊金網（株）製：ワイヤーメッシュフィルター等があげられる。 The gas that has passed through each absorber 12 passes through the separation filter 31 and is discharged from the NMP recovery device 11a as exhaust gas C. The separation filter 31 is a filter for finally separating an aqueous liquid or the like in the exhaust gas C and may be any filter that can separate droplets of 3 μm or more. An example of this is a wire mesh filter manufactured by Tokyo Special Wire Mesh Co., Ltd.

また、吸収部１２ｂや１２ｃを通った水系液等Ａは、液溜め部１７に溜められるが、その全部又は一部は、送液配管２５で循環される。そして、バランスアウトした水系液等Ａがこの液溜め部１７で溢れると、開口部１８から、集液部２２、受け部２３及びスプレー装置２４を経由して、その下の吸収部１２ａ又は１２ｂに送られる。 Further, the aqueous liquid A or the like that has passed through the absorbing parts 12b and 12c is stored in the liquid storage part 17, but all or a part thereof is circulated through the liquid supply pipe 25. Then, when the balanced out aqueous liquid A or the like overflows in the liquid reservoir 17, it passes from the opening 18 to the absorption part 12 a or 12 b below it via the liquid collection part 22, the receiving part 23 and the spray device 24. Sent.

このように水系液等Ａが循環されながら、下方に落下し、かつ、同伴ガスＢが上昇していくと、吸収部１２ａ、吸収部１２ｂ、及び吸収部１２ｃの順に、その吸収部を通る水系液等のＮＭＰ濃度が低下していく。このため、液貯蔵部１４中のＮＭＰ濃度が最も高くなり、ここより、回収配管２７を通じて、ＮＭＰ水溶液Ｅを回収することができる。 When the water-based liquid A or the like is circulated in this way and falls downward and the accompanying gas B rises, the water system that passes through the absorption section in the order of the absorption section 12a, the absorption section 12b, and the absorption section 12c. NMP concentration of liquid etc. decreases. For this reason, the NMP concentration in the liquid storage unit 14 becomes the highest, and the NMP aqueous solution E can be recovered through the recovery pipe 27 from here.

また、上記分離フィルター３１で、残存する水系液等は回収される。そして、排ガス中に操作温度見合いの水分が蒸留同伴されるので、水供給配管２８より、補給水Ｄを補給する必要がある。 Further, the remaining aqueous liquid or the like is recovered by the separation filter 31. And since the water corresponding to the operating temperature is distilled along with the exhaust gas, it is necessary to replenish makeup water D from the water supply pipe 28.

一方、熱交換器２９を設けて、送液配管２５ｃを通って循環する同伴ガスＢを冷却して、スプレー装置２４ｃより落下させることにより、吸収部１２ｃを上昇する同伴ガスＢを冷却することができる。これにより、この水系液等Ａに含まれる水の水滴をより大きくすることができ、吸収部１２ｃ又は分離フィルター３１で、水系液等Ａの水滴を分離し、排ガスＣと共に、系外に出るのを防止できる。 On the other hand, by providing the heat exchanger 29, the accompanying gas B circulating through the liquid feeding pipe 25c is cooled and dropped from the spray device 24c, thereby cooling the accompanying gas B rising the absorption part 12c. it can. As a result, water droplets contained in the aqueous liquid etc. A can be made larger, and the water droplets of the aqueous liquid etc. A are separated by the absorber 12c or the separation filter 31 and go out of the system together with the exhaust gas C. Can be prevented.

なお、図１においては、３つの吸収部１２を１つの吸収塔１３ａの中に、直列に並べたが、それぞれの吸収部１２をそれぞれ別の吸収塔に入れ、同伴ガスＢの流れが直列になるように、それぞれを連結してもよい。この場合、水系液等Ａと同伴ガスＢとの流れは、それぞれ並流であっても、向流であってもよい。 In FIG. 1, three absorption sections 12 are arranged in series in one absorption tower 13 a, but each absorption section 12 is put in a separate absorption tower, and the flow of entrained gas B is in series. Each may be connected so that it becomes. In this case, the flow of the aqueous liquid A or the like and the entrained gas B may be cocurrent or countercurrent.

次に、この発明にかかるＮＭＰ回収装置の他の例を、図３を用いて説明する。
図３に示すＮＭＰ回収装置１１ｂは、同伴ガスＢ中のＮＭＰをまず、濃縮器４１で濃縮除去して、ＮＭＰ濃度の低下した同伴ガスＢ’を、図１に示す吸収塔１３ａと同様の吸収塔１３ｂに送り、同伴ガスＢ’中のＮＭＰを回収する装置である。 Next, another example of the NMP recovery apparatus according to the present invention will be described with reference to FIG.
The NMP recovery device 11b shown in FIG. 3 first concentrates and removes NMP in the accompanying gas B by the concentrator 41, and absorbs the accompanying gas B ′ having a reduced NMP concentration in the same manner as the absorption tower 13a shown in FIG. This is an apparatus for sending NMP in the accompanying gas B ′ to the tower 13b.

上記濃縮器４１は、その内部に、上記した吸収部１２と同様の吸収部４８を有する。そして、その下方には、ＮＭＰを濃縮した水系液等、すなわち、濃縮液を溜める濃縮液溜め部４９が設けられる。そして、この濃縮液溜め部４９から、その濃縮液を上記吸収部４８に、詳しくは、上記吸収部４８内の充填物の上方に送る循環配管４４が設けられ、この濃縮液を濃縮器４１内で循環させることができる。 The concentrator 41 has an absorption part 48 similar to the above-described absorption part 12 inside. Below that, an aqueous liquid or the like concentrated NMP, that is, a concentrated liquid reservoir 49 for storing the concentrated liquid is provided. Then, a circulation pipe 44 is provided for sending the concentrated liquid from the concentrated liquid reservoir 49 to the absorbing section 48, more specifically, above the filling in the absorbing section 48. It can be circulated with.

なお、図３に示すように、循環ラインの上端は、濃縮器４１内の上端部に導入して、スプレー装置５１より下方に降らせてもよく、濃縮器４１より上方の同伴ガスＢの導入配管５２に接続してもよく、また、その両方に配管を設けてもよい。循環ラインの上端を、濃縮器４１より上方の同伴ガスＢの導入配管５２に接続することにより、同伴ガスＢ中のＮＭＰ濃度が高いとき、これを希釈することが可能となる。 As shown in FIG. 3, the upper end of the circulation line may be introduced into the upper end of the concentrator 41 and lowered below the spray device 51, and the accompanying gas B introduction pipe above the concentrator 41. 52 may be connected, and piping may be provided in both of them. By connecting the upper end of the circulation line to the introduction pipe 52 of the accompanying gas B above the concentrator 41, when the NMP concentration in the accompanying gas B is high, it can be diluted.

図３に示す上記吸収塔１３ｂは、２段であるが、濃縮器４１が１段分の能力を有するので、ＮＭＰ回収装置１１ｂ全体としては、実質３段の段数を有する。また、上記吸収塔１３ｂの機能は、吸収塔１３ａの機能と同様であり、図３においては、図１の中段部分（吸収部１２ｂ等）を除いた形で、記載した。 Although the absorption tower 13b shown in FIG. 3 has two stages, since the concentrator 41 has the capacity of one stage, the NMP recovery apparatus 11b as a whole has substantially three stages. Further, the function of the absorption tower 13b is the same as that of the absorption tower 13a, and in FIG. 3, it is shown in a form excluding the middle part (absorption section 12b and the like) of FIG.

上記濃縮器４１と吸収塔１３ｂとの間には、上記濃縮器４１から排出される排ガス、すなわち、同伴ガスＢ’を吸収塔１３ｂの最下段の吸収部１２ａと液貯蔵部１４との間の部分に送る送ガス配管４２が設けられている。 Between the concentrator 41 and the absorption tower 13b, the exhaust gas discharged from the concentrator 41, that is, the entrained gas B ′, is interposed between the lowermost absorption section 12a and the liquid storage section 14 of the absorption tower 13b. A gas supply pipe 42 to be sent to the part is provided.

さらに、上記液貯蔵部１４内の水系液等の一部を、上記濃縮器４１又は上記濃縮器４１に配された配管に送る送液配管４３が設けられる。そして、図１の回収配管２７の代わりに、濃縮器４１の循環配管４４から分岐させて、回収配管４５が設けられる。これは、このＮＭＰ回収装置１１ｂのうち、最もＮＭＰ濃度が高いのが、濃縮器４１内の水系液等であるので、ここから、ＮＭＰ水溶液Ｅを回収するためである。 Furthermore, a liquid feeding pipe 43 is provided for sending a part of the aqueous liquid or the like in the liquid storage unit 14 to the concentrator 41 or a pipe disposed in the concentrator 41. And instead of the collection | recovery piping 27 of FIG. 1, it branches from the circulation piping 44 of the concentrator 41, and the collection | recovery piping 45 is provided. This is for recovering the NMP aqueous solution E from the NMP recovery device 11b having the highest NMP concentration, such as the aqueous liquid in the concentrator 41.

上記濃縮器４１から同伴ガスＢ’を排出する排ガス排出部４６には、分離フィルター４７が設けられる。この分離フィルター４７は、上記した分離フィルター３１と同様のものであり、上記濃縮器から排出される同伴ガスＢ’から、この排ガスに含まれる水系液分を分離することができる。 A separation filter 47 is provided in the exhaust gas discharge section 46 that discharges the accompanying gas B ′ from the concentrator 41. The separation filter 47 is the same as the separation filter 31 described above, and can separate an aqueous liquid component contained in the exhaust gas from the accompanying gas B ′ discharged from the concentrator.

次に、図３に示すＮＭＰ回収装置１１ｂを用いたＮＭＰの回収方法について説明する。
まず、ＮＭＰ回収装置１１ｂの濃縮器４１内の濃縮液Ｆをこの濃縮器４１内で循環させる。また、吸収塔１３ｂ内は、上記吸収塔１３ａの場合と同様に、水系液等Ａをそれぞれ循環させる。
そして、この濃縮器４１の上部に同伴ガスＢを導入する。導入された同伴ガスＢは、吸収部４８内で濃縮液Ｆと接触し、同伴ガスＢ中のＮＭＰを濃縮液Ｆに吸収させる。 Next, an NMP recovery method using the NMP recovery device 11b shown in FIG. 3 will be described.
First, the concentrate F in the concentrator 41 of the NMP recovery apparatus 11b is circulated in the concentrator 41. Further, in the absorption tower 13b, an aqueous liquid A or the like is circulated similarly to the case of the absorption tower 13a.
Then, the accompanying gas B is introduced into the upper part of the concentrator 41. The introduced entrained gas B comes into contact with the concentrated liquid F in the absorption section 48 and causes the concentrated liquid F to absorb NMP in the accompanying gas B.

次いで、ＮＭＰがある程度除かれた同伴ガスＢ’は、分離フィルター４７を通って、吸収塔１３ｂの、最下段の吸収部１２ａと液貯蔵部１４との間の部分に導入される。そして、上記した吸収塔１３ａの場合と同様にして、ＮＭＰが吸収され、排ガスＣが吸収塔１３ｂの上部より排出される。 Next, the entrained gas B ′ from which NMP has been removed to some extent passes through the separation filter 47 and is introduced into a portion of the absorption tower 13 b between the lowermost absorption section 12 a and the liquid storage section 14. And NMP is absorbed and exhaust gas C is discharged | emitted from the upper part of the absorption tower 13b similarly to the case of the above-mentioned absorption tower 13a.

吸収塔１３ｂの中で、ＮＭＰ濃度の最も高い液貯蔵部１４中の水系液等Ａの一部は、送液配管４３を経由して、濃縮器４１又はその配管に送られる。この液貯蔵部１４中の水系液等Ａの一部が送られる場所は、循環配管４４、濃縮器４１、又は濃縮器４１の分離フィルター４７の前流部のいずれであってもよい。この水系液等Ａの一部は、濃縮液ＦよりＮＭＰ濃度が低いので、循環液として使用するには好適である。また、濃縮器４１の分離フィルター４７の前流部にスプレーすることにより、分離フィルター４７を洗浄すると同時に、同伴ガスＢ’中のＮＭＰを水系液等に濃縮することができる。そして、分離フィルター４７で分離した水系液等を濃縮器４１内に洗い落とすことができる。 In the absorption tower 13 b, a part of the aqueous liquid A or the like in the liquid storage unit 14 having the highest NMP concentration is sent to the concentrator 41 or the pipe via the liquid feeding pipe 43. The place where a part of the aqueous liquid A or the like in the liquid storage unit 14 is sent may be any of the circulation pipe 44, the concentrator 41, or the upstream portion of the separation filter 47 of the concentrator 41. A part of the aqueous liquid A or the like has a lower NMP concentration than the concentrated liquid F, and therefore is suitable for use as a circulating liquid. Further, by spraying the upstream portion of the separation filter 47 of the concentrator 41, the separation filter 47 can be washed and at the same time, the NMP in the accompanying gas B 'can be concentrated into an aqueous liquid or the like. Then, the aqueous liquid or the like separated by the separation filter 47 can be washed out in the concentrator 41.

そして、循環配管４４から分岐した回収配管４５から、ＮＭＰ水溶液を回収することができる。 Then, the NMP aqueous solution can be recovered from the recovery pipe 45 branched from the circulation pipe 44.

ところで、図３のＮＭＰ回収装置１１ｂの濃縮器４１の同伴ガスＢと濃縮液Ｆとは、並流であるが、図４に示すように、同伴ガスＢと濃縮液Ｆとが向流となるような濃縮器４１’を用いたＮＭＰ回収装置１１ｃを使用してもよい。この場合、同伴ガスＢの導入部は、吸収部４８の下方となり、分離フィルター４７は必要なくなる。その他は、図３に示すＮＭＰ回収装置１１ｂと同様で、ＮＭＰの回収方法も同様である。 Incidentally, the entrained gas B and the concentrate F of the concentrator 41 of the NMP recovery apparatus 11b of FIG. 3 are cocurrent, but the entrained gas B and the concentrate F are countercurrent as shown in FIG. You may use NMP collection | recovery apparatus 11c using such concentrator 41 '. In this case, the introduction part of the accompanying gas B is below the absorption part 48, and the separation filter 47 is not necessary. Others are the same as the NMP recovery apparatus 11b shown in FIG. 3, and the NMP recovery method is also the same.

上記の各ＮＭＰ回収装置において、液貯蔵部１４及び濃縮液溜め部４９の液量等を制御することにより、自動運転が可能となる。その例を図３に示すＮＭＰ回収装置１１ｂを用いて説明する。 In each of the NMP recovery devices described above, automatic operation is possible by controlling the amount of liquid in the liquid storage section 14 and the concentrated liquid reservoir section 49. An example thereof will be described using the NMP recovery device 11b shown in FIG.

液貯蔵部１４の液量は、濃縮器４１へ水系液等を送ったり、排ガスＣ中に同伴されて出て行く水分量によって、減少していく。このため、液貯蔵部１４の所定位置にセンサ６１を設け、液貯蔵部１４の液量によって、水供給配管２８にあるバルブ６２を開閉するようにする。これにより、液貯蔵部１４の液量を一定量以下とならないようにすることができ、吸収塔１３ｂを安定的に運転することができる。 The amount of liquid stored in the liquid storage unit 14 decreases depending on the amount of water that is sent out to the concentrator 41 or is accompanied by the exhaust gas C. For this reason, a sensor 61 is provided at a predetermined position of the liquid storage unit 14, and the valve 62 in the water supply pipe 28 is opened and closed according to the amount of liquid in the liquid storage unit 14. Thereby, the liquid quantity of the liquid storage part 14 can be made not to become below a fixed quantity, and the absorption tower 13b can be operated stably.

また、ＮＭＰ水溶液Ｅを抜き出すと、濃縮液溜め部４９の液量が減少し、濃縮器４１内の循環が困難となる場合がある。この場合、濃縮液溜め部４９の所定の位置にセンサ６３を設けることにより、所定量以下となると、バルブ６４を開放し、液貯蔵部１４から水系液等を濃縮器４１内に送り込み、そして、濃縮液溜め部４９の液量が所定量となると、バルブ６４を閉めることにより、濃縮液溜め部４９の液量をほぼ一定に保つことができる。 Further, when the NMP aqueous solution E is extracted, the amount of liquid in the concentrated liquid reservoir 49 decreases, and circulation in the concentrator 41 may become difficult. In this case, by providing the sensor 63 at a predetermined position of the concentrated liquid reservoir 49, the valve 64 is opened when the predetermined amount or less is reached, and the aqueous liquid or the like is sent from the liquid storage unit 14 into the concentrator 41. When the liquid volume in the concentrated liquid reservoir 49 reaches a predetermined level, the liquid volume in the concentrated liquid reservoir 49 can be kept substantially constant by closing the valve 64.

さらに、ＮＭＰ水溶液Ｅの取り出しは、濃縮液Ｆの濃度で判断することができる。このため、循環配管４４に濃度センサ６５を取り付け、濃縮液Ｆが所定の濃度となると、バルブ６６を開け、ＮＭＰ水溶液を取り出すことができる。すると、濃縮液溜め部４９の液量が減少するので、上記したように、液貯蔵部１４から水系液等を濃縮器４１内に送り込まれる。これにより、濃縮液ＦのＮＭＰ濃度が低下し、所定濃度以下となると、バルブ６６が閉まる。これらにより、安定的に、所定濃度のＮＭＰ水溶液Ｅを回収することができる。 Furthermore, the removal of the NMP aqueous solution E can be determined by the concentration of the concentrate F. For this reason, the concentration sensor 65 is attached to the circulation pipe 44, and when the concentrate F reaches a predetermined concentration, the valve 66 can be opened to extract the NMP aqueous solution. Then, the amount of the liquid in the concentrated liquid reservoir 49 decreases, so that the aqueous liquid or the like is sent from the liquid storage unit 14 into the concentrator 41 as described above. As a result, when the NMP concentration of the concentrate F decreases and falls below a predetermined concentration, the valve 66 is closed. As a result, the NMP aqueous solution E having a predetermined concentration can be recovered stably.

また次に、図５に示すＮＭＰ回収装置１１ｄを用いたＮＭＰの回収について説明する。この装置は、図３及び図４においては濃縮器４１、４１’で行う同伴ガスＢ中のＮＭＰの濃縮を、吸収塔１３ｃに同伴ガスＢを導入する液接触配管７１と、この液接触配管７１に水系液等を送る還流配管７２とにより行い、同伴ガスＢ中のＮＭＰを回収する装置である。 Next, recovery of NMP using the NMP recovery apparatus 11d shown in FIG. 5 will be described. In FIG. 3 and FIG. 4, this apparatus includes a liquid contact pipe 71 for introducing the accompanying gas B into the absorption tower 13 c, and a liquid contact pipe 71 for concentrating NMP in the accompanying gas B performed by the concentrators 41 and 41 ′. This is an apparatus for recovering NMP in the accompanying gas B through a reflux pipe 72 for sending an aqueous liquid or the like.

このＮＭＰ回収装置１１ｄの吸収塔１３ｃは、上記の吸収塔１３ｂと同様に、複数の吸収部１２を上下方向に直列に配し、２つの吸収部１２の間の境界部に、上記の液溜め部１７、開口部１８、送り板１９などを設け、さらに、液溜め部１７から溢れる水系液等を下方に落下させる集液装置１５を設けてある。また、同様に最下段の吸収部１２ａの下方に液貯蔵部１４を設け、その最下段の吸収部１２ａと液貯蔵部１４との間の下段境界部にも、液溜め部１７を設けてあるが、この下段境界部にある液溜め部１７の下には、水系液等を下方へ落下させる受け部２３やスプレー装置２４を設けていない。 The absorption tower 13c of the NMP recovery device 11d has a plurality of absorption sections 12 arranged in series in the vertical direction, similar to the above-described absorption tower 13b, and the above-described liquid reservoir at the boundary between the two absorption sections 12. A liquid collecting device 15 is provided for dropping an aqueous liquid overflowing from the liquid reservoir 17 downward. Similarly, a liquid storage section 14 is provided below the lowermost absorption section 12a, and a liquid reservoir section 17 is also provided at the lower boundary between the lowermost absorption section 12a and the liquid storage section 14. However, the receiving part 23 and the spray device 24 for dropping the aqueous liquid or the like downward are not provided below the liquid reservoir part 17 at the lower boundary part.

また、上記の下段境界部に設けた液溜め部１７と、上記の液貯蔵部１４との間に分離フィルター７３を設けてある。この分離フィルター７３と液貯蔵部１４との間に、吸収塔１３ｃ外から同伴ガスＢを供給する導入配管５２と吸収塔１３ｃとを接続する液接触配管７１の出口７１ａを設けてある。この液接触配管７１は、内部に設けた供給口であるスプレーノズル７４から供給された水系液等と上記ガスＢとを内部で接触させ、かつ、吸収塔１３ｃの外部から吸収塔１３ｃ内に水系液等を導入するものである。 In addition, a separation filter 73 is provided between the liquid reservoir 17 provided at the lower boundary part and the liquid storage part 14. Between the separation filter 73 and the liquid storage unit 14, an outlet 71a of a liquid contact pipe 71 for connecting the introduction pipe 52 for supplying the accompanying gas B from the outside of the absorption tower 13c and the absorption tower 13c is provided. The liquid contact pipe 71 causes the aqueous liquid or the like supplied from a spray nozzle 74, which is a supply port provided therein, to contact the gas B inside, and the aqueous system enters the absorption tower 13c from the outside of the absorption tower 13c. A liquid or the like is introduced.

この液接触配管７１は、導入配管５２から吸収塔１３ｃへ向けて上方向から下方向となる傾斜を有しているとよく、鉛直方向に延びた部分又は鉛直方向に近い角度である部分を有していてもよい。鉛直方向に延びた部分や傾斜があることにより、液接触配管７１に供給される水系液等を吸収塔１３ｃの液貯蔵部１４に向かって落とすことができる。 The liquid contact pipe 71 may have an inclination from the upper side to the lower side from the introduction pipe 52 to the absorption tower 13c, and has a part extending in the vertical direction or a part having an angle close to the vertical direction. You may do it. By having a portion extending in the vertical direction and an inclination, an aqueous liquid or the like supplied to the liquid contact pipe 71 can be dropped toward the liquid storage unit 14 of the absorption tower 13c.

上記の出口７１ａは、液接触配管７１が水平に近い傾斜を有している場合は、その傾斜のまま吸収塔１３ｃ内に導入された先端部分に設けられてよい。また、液接触配管７１が鉛直方向又は鉛直方向に近い角度である部分を有している場合は、より水平に近くなるように折り曲げた部分を設け、その折り曲げた先に出口７１ａを設けると、吸収塔１３ｃに導入しやすい。 In the case where the liquid contact pipe 71 has a substantially horizontal inclination, the outlet 71a may be provided at a tip portion introduced into the absorption tower 13c with the inclination. Further, when the liquid contact pipe 71 has a vertical direction or a portion having an angle close to the vertical direction, a bent portion is provided so as to be closer to the horizontal, and an outlet 71a is provided at the bent end. Easy to introduce into the absorption tower 13c.

なお、液接触配管７１が、図５の記載のように鉛直方向に延びた部分又は鉛直方向に近い部分を有していて、かつ、その部分の内部にスプレーノズル７４を設けていると、スプレーノズル７４から供給された、微細化して散布された水系液等が重力に引かれて液接触配管７１の内面に落下するまで、長時間に亘って微細化した状態で同伴ガスＢと接触し続けさせることが出来るので好ましい。 If the liquid contact pipe 71 has a portion extending in the vertical direction or a portion close to the vertical direction as shown in FIG. 5 and a spray nozzle 74 is provided inside the portion, spraying is performed. The finely sprayed aqueous liquid supplied from the nozzle 74 is kept in contact with the entrained gas B in a refined state for a long time until it is pulled by gravity and falls onto the inner surface of the liquid contact pipe 71. This is preferable.

上記のスプレーノズル７４は、図５の記載では液接触配管７１が鉛直方向へ延びた箇所に高さ方向に複数個並べ、それぞれの散布する方向を同伴ガスＢの流れ方向へ向けて設けてあるが、水平方向に並べてもよいし、同伴ガスＢの流れ方向と反対方向に向けてもよい。ただし、複数個設ける場合には、高さ方向に並べると、水平方向に並べるよりも、液接触配管７１の必要な断面積を小さくすることができる。また、同伴ガスＢの流れ方向と反対方向にスプレーノズル７４を向けても、散布した水系液等は落下するので、最終的には順流となる。 In the description of FIG. 5, a plurality of the spray nozzles 74 are arranged in the height direction at locations where the liquid contact pipes 71 extend in the vertical direction, and each spraying direction is provided in the flow direction of the accompanying gas B. However, they may be arranged in the horizontal direction or in the direction opposite to the flow direction of the accompanying gas B. However, when a plurality of the liquid contact pipes 71 are arranged in the height direction, the necessary cross-sectional area of the liquid contact pipe 71 can be made smaller than in the horizontal direction. Further, even if the spray nozzle 74 is directed in the direction opposite to the flow direction of the accompanying gas B, the sprayed aqueous liquid or the like falls, so that it finally becomes a forward flow.

上記の液接触配管７１に導入された同伴ガスＢ中のＮＭＰの少なくとも一部は、スプレーノズル７４から液接触配管７１内に供給されて散布された水系液等により吸収されて液貯蔵部１４に蓄積される。この液接触配管７１には充填物が無いために、同伴ガスＢが通過する際の圧力損失をほとんど生じさせることなく、同伴ガスＢからＮＭＰを回収することができる。こうして水系液等に吸収されることでＮＭＰの含有量が減少した同伴ガスＢ’は、吸収塔１３ｃの下部に導入され、分離フィルター７３を通して吸収塔１３ｃの上方へ向かう。液貯蔵部１４に蓄積された水系液等の一部は、液貯蔵部１４から送液ポンプ２６を用いて還流配管７２を通して供給口であるスプレーノズル７４から散布されて液接触配管７１内に供給され、接触した同伴ガスＢから再びＮＭＰを吸収する。このようにしてＮＭＰを何度も吸収して濃縮した水系液等が、液貯蔵部１４に蓄積されていき、その一部は、回収配管４５から回収される。 At least a part of the NMP in the accompanying gas B introduced into the liquid contact pipe 71 is absorbed by the aqueous liquid or the like supplied and sprayed from the spray nozzle 74 into the liquid contact pipe 71 to the liquid storage unit 14. Accumulated. Since there is no filling in the liquid contact pipe 71, NMP can be recovered from the accompanying gas B with almost no pressure loss when the accompanying gas B passes. The entrained gas B ′ whose NMP content has been reduced by being absorbed in the aqueous liquid or the like in this way is introduced into the lower part of the absorption tower 13 c and travels upward through the separation filter 73 to the absorption tower 13 c. A part of the aqueous liquid or the like accumulated in the liquid storage unit 14 is sprayed from the spray nozzle 74 as a supply port through the reflux pipe 72 from the liquid storage unit 14 using the liquid feed pump 26 and supplied into the liquid contact pipe 71. Then, NMP is absorbed again from the accompanying entrained gas B. Thus, the aqueous liquid etc. which absorbed NMP many times and concentrated are accumulate | stored in the liquid storage part 14, A part is collect | recovered from the collection | recovery piping 45. FIG.

上記の同伴ガスＢ’が吸収塔１３ｃの下部から上方へ向かう際に通過する、吸収部１２ａと分離フィルター７３との間の下段境界部には、吸収部１２ａから落下した水系液等を分離フィルター７３まで落とさないための液溜め部１７及び送り板１９が設けられ、かつ、その間を通すための開口部１８が形成されている。ただし、この下段境界部に設けられた液溜め部１７の下には吸収部１２が無いため、さらに下方へ落下させることは好ましくない。そのため、この液溜め部１７に蓄積された水系液等は、送液ポンプ２６から送液配管２５を通じて、吸収部１２ａの上方にあるスプレー装置２４に送り、吸収部１２ａに送って同伴ガスＢ’中のＮＭＰを吸収する。また、吸収塔１３ａ及び１３ｂと同様に、吸収部１２ａでもＮＭＰを吸収して、排ガスＣを吸収塔１３ｃの塔頂から排出される。 The above-mentioned entrained gas B ′ passes as it goes upward from the lower part of the absorption tower 13c, and a separation filter is used to separate the aqueous liquid dropped from the absorption part 12a at the lower boundary between the absorption part 12a and the separation filter 73. A liquid reservoir 17 and a feed plate 19 for preventing the liquid from dropping to 73 are provided, and an opening 18 for passing between them is formed. However, since there is no absorption part 12 under the liquid reservoir part 17 provided in this lower stage boundary part, it is not preferable to drop further downward. Therefore, the aqueous liquid or the like accumulated in the liquid reservoir 17 is sent from the liquid feed pump 26 through the liquid feed pipe 25 to the spray device 24 above the absorber 12a, and sent to the absorber 12a to be accompanied gas B ′. Absorbs NMP in it. Similarly to the absorption towers 13a and 13b, the absorption section 12a also absorbs NMP, and exhaust gas C is discharged from the top of the absorption tower 13c.

また、上記下段境界部にある液溜め部１７の液量を調整して溢れないようにするために、その液溜め部１７の水系液等の一部は、送液ポンプ２６により、送液配管２５（２５ａ）から移送配管７５を経由して還流配管７２の先の、液接触配管７１内にあるスプレーノズル７４へ送られる。また、液溜め部１７から水系液等を抜き出す移送配管７５を、液貯蔵部１４に直接繋げてもよい。ただし、この液溜め部１７に溜まった水系液等は、液貯蔵部１４に蓄積された水系液等よりもＮＭＰ濃度が低いため、移送配管７５から還流配管７２を通して液接触配管７１に供給することで、液接触配管７１内でＮＭＰを吸収させてから液貯蔵部１４に送るようにすると、供給される水系液等の濃度が低いために、ＮＭＰをより効率的に吸収できるので好ましい。どちらの場合も、上記下段境界部にある液溜め部１７から移送配管７５を通った水系液等が液貯蔵部１４に溜まることになり、ＮＭＰ濃度の高い水系液等を回収配管４５から回収することで減った液貯蔵部１４の水系液等を補充することができる。 Further, in order to prevent the liquid reservoir 17 at the lower boundary portion from overflowing by adjusting the amount of liquid, a part of the aqueous liquid or the like in the liquid reservoir 17 is supplied by a liquid feed pump 26 by a liquid feed pipe. 25 (25a) through the transfer pipe 75 and sent to the spray nozzle 74 in the liquid contact pipe 71 ahead of the reflux pipe 72. Further, a transfer pipe 75 for extracting an aqueous liquid or the like from the liquid reservoir 17 may be directly connected to the liquid storage unit 14. However, since the NMP concentration of the aqueous liquid or the like stored in the liquid reservoir 17 is lower than that of the aqueous liquid or the like accumulated in the liquid storage part 14, it is supplied from the transfer pipe 75 to the liquid contact pipe 71 through the reflux pipe 72. Thus, it is preferable that NMP is absorbed in the liquid contact pipe 71 and then sent to the liquid storage unit 14 because the concentration of the supplied aqueous liquid or the like is low, so that NMP can be absorbed more efficiently. In either case, the aqueous liquid or the like that has passed through the transfer pipe 75 from the liquid reservoir 17 at the lower boundary is collected in the liquid storage part 14, and the aqueous liquid or the like having a high NMP concentration is recovered from the recovery pipe 45. Thus, it is possible to replenish the aqueous liquid or the like in the liquid storage unit 14 that has been reduced.

この液貯蔵部１４の水系液等の量の調整は、液貯蔵部１４の所定位置にセンサ７６を設けて、液貯蔵部１４の液量をチェックすることによって、移送配管７５のバルブ７７、水供給配管２８のバルブ６２及び回収配管４５のバルブ７８を適切に開閉して調整するようにする。これにより、液貯蔵部１４の液量を一定量以下とならないようにすることができ、吸収塔１３ｃを安定的に運転することができる。また、上記下段境界部の液溜め部１７の所定位置にもセンサ７９を設けて、このセンサ７９に従ってバルブ７７を適切に調整すると、この液溜め部１７が溢れることを防止できる。 The adjustment of the amount of the aqueous liquid or the like in the liquid storage unit 14 is performed by providing a sensor 76 at a predetermined position of the liquid storage unit 14 and checking the amount of liquid in the liquid storage unit 14, so that the valve 77 of the transfer pipe 75, water The valve 62 of the supply pipe 28 and the valve 78 of the recovery pipe 45 are appropriately opened and closed for adjustment. Thereby, the liquid quantity of the liquid storage part 14 can be made not to become below a fixed quantity, and the absorption tower 13c can be operated stably. Further, if a sensor 79 is also provided at a predetermined position of the liquid reservoir portion 17 at the lower boundary portion and the valve 77 is appropriately adjusted according to the sensor 79, the liquid reservoir portion 17 can be prevented from overflowing.

なお、吸収塔１３ｃの上部では、上記の吸収塔１３ａ及び１３ｂと同様に、吸収部に送られた水系液等を、吸収部の充填物の中を上方から下方に向かって流し、ＮＭＰの含有量が低下した同伴ガスＢ’からさらにＮＭＰを吸収する。ここで供給する水系液等は、送液配管２５から送られてくる水系液等だけではなく、外部から補給水Ｄとして追加される分も含む。 In addition, in the upper part of the absorption tower 13c, like the above-mentioned absorption towers 13a and 13b, the aqueous liquid or the like sent to the absorption section is caused to flow from the upper side to the lower side through the packing of the absorption section, thereby containing NMP. NMP is further absorbed from the accompanying gas B ′ whose amount has decreased. The aqueous liquid supplied here includes not only the aqueous liquid and the like sent from the liquid supply pipe 25 but also the amount added as makeup water D from the outside.

このような吸収塔１３ｃとそれに繋がる液接触配管７１を有するＮＭＰ回収装置１１ｄに、導入配管５２から液接触配管７１の上方より同伴ガスＢを導入し、液接触配管７１の内部でスプレーノズル７４から供給された水系液等と同伴ガスＢとを接触させて同伴ガスＢ中のＮＭＰを吸収しつつ、同伴ガスＢと水系液等とを液接触配管７１の上方から下方に向かって流して、吸収塔１３ｃ内に導入する。ここまででＮＭＰ濃度の減少した同伴ガスＢ’を、吸収塔１３ｃ内の吸収部１２において水系液と接触させて、さらにＮＭＰを吸収させた排ガスＣが吸収塔１３ｃの上部より排出される。図５に示す吸収塔１３ｃは２段であるが、液接触配管７１が１段分の能力を有するので、ＮＭＰ回収装置１１ｄ全体としては、実質３段の段数を有する。 The entrained gas B is introduced from above the liquid contact pipe 71 into the NMP recovery apparatus 11d having such an absorption tower 13c and the liquid contact pipe 71 connected to the absorption tower 13c, and from the spray nozzle 74 inside the liquid contact pipe 71. While the supplied aqueous liquid or the like and the accompanying gas B are brought into contact with each other to absorb NMP in the accompanying gas B, the accompanying gas B and the aqueous liquid or the like are caused to flow downward from above the liquid contact pipe 71 to be absorbed. Introduce into the tower 13c. Thus far, the entrained gas B 'having a reduced NMP concentration is brought into contact with the aqueous liquid in the absorption section 12 in the absorption tower 13c, and the exhaust gas C that has further absorbed NMP is discharged from the upper portion of the absorption tower 13c. Although the absorption tower 13c shown in FIG. 5 has two stages, since the liquid contact pipe 71 has the capacity of one stage, the entire NMP recovery apparatus 11d has substantially three stages.

なお、吸収塔１３ａ及び１３ｂと同様に、吸収塔１３ｃの送液配管２５に、水系液等を冷却する熱交換器２９を設けていると、同様にガスを冷却して、排ガスＣ中の水分量をより減らすことができるので好ましい。 Similarly to the absorption towers 13a and 13b, when the heat exchanger 29 for cooling the aqueous liquid or the like is provided in the liquid feeding pipe 25 of the absorption tower 13c, the gas is cooled in the same manner, and the moisture in the exhaust gas C This is preferable because the amount can be further reduced.

この発明にかかるＮＭＰ回収装置１１ａ〜１１ｄに供される同伴ガスＢ中のＮＭＰ量は、１００ｐｐｍ以上がよく、５００ｐｐｍ以上が好ましい。１００ｐｐｍより少ないと、この発明にかかるＮＭＰ回収装置１１ａ〜１１ｄを用いる必要性がなくなる。一方、同伴ガスＢ中のＮＭＰ量の上限値は、ＮＭＰの爆発下限界となる濃度の１／４がよい。具体的には、空気中だと、２２５０ｐｐｍがよく、２０００ｐｐｍが好ましく、１０００ｐｐｍがより好ましい。ＮＭＰの爆発下限界となる濃度の１／４より高い濃度だと、この発明にかかるＮＭＰ回収装置１１ａ〜１１ｄの工程内において、安全上好ましくない濃度領域に入るので、好ましくない。 The amount of NMP in the accompanying gas B supplied to the NMP recovery apparatuses 11a to 11d according to the present invention is preferably 100 ppm or more, and more preferably 500 ppm or more. If it is less than 100 ppm, the necessity of using the NMP recovery devices 11a to 11d according to the present invention is eliminated. On the other hand, the upper limit of the amount of NMP in the accompanying gas B is preferably ¼ of the concentration that is the lower limit of explosion of NMP. Specifically, in the air, 2250 ppm is good, 2000 ppm is preferable, and 1000 ppm is more preferable. If the concentration is higher than 1/4 of the concentration that is the lower limit of explosion of NMP, it is not preferable because it enters a concentration region that is unfavorable for safety in the process of the NMP recovery devices 11a to 11d according to the present invention.

次に、この発明について実施例を用いてより詳細に説明する。
ＮＭＰ回収装置として、図３に示す装置を用いた。また、各吸収部内の充填物として、菱化フォワード（株）製、規則充填物を用いた。さらに、各分離フィルターとしては、東京特殊金属金網（株）製：ワイヤーメッシュフィルターを用いた。
また、濃縮器４１内の総体積は５２．０ｍ^３、吸収部４８に使用した充填物の体積は９．３ｍ^３、吸収塔１３ｂ内の総体積は１０２．８ｍ^３、各吸収部１２に使用した充填物の体積は、それぞれ４０．０ｍ^３であった。 Next, the present invention will be described in more detail using examples.
The apparatus shown in FIG. 3 was used as the NMP recovery apparatus. Moreover, the Ryoka Forward Co., Ltd. product and a regular packing were used as a packing in each absorption part. Furthermore, as each separation filter, Tokyo Special Metal Wire Mesh Co., Ltd .: wire mesh filter was used.
The total volume of the concentrator 41 52.0M ^3, the volume of the filler used in the absorber 48 is 9.3 m ^3, the total volume of the absorption tower 13b is 102.8M ^3, used for each absorber 12 The volume of the filled material was 40.0 m ³ each.

（実施例１）
表１に示す成分を有するガスを表１に示す流速で、濃縮器４１に導入した。そして、ＮＭＰ濃度が８０重量％のときに、回収配管４５からＮＭＰ水溶液Ｅを回収するように、各センサやバルブ等を調整した。なお、熱交換器２９による水系液等Ａの熱交換は、行わなかった。
その結果、１２時間連続運転したところ、排ガスＣ中のＮＭＰ濃度は１ｐｐｍ未満で安定していた。１２時間経過後の結果を表１に示す。 Example 1
A gas having the components shown in Table 1 was introduced into the concentrator 41 at a flow rate shown in Table 1. And each sensor, valve | bulb, etc. were adjusted so that NMP aqueous solution E might be collect | recovered from the collection | recovery piping 45, when NMP density | concentration is 80 weight%. The heat exchange of the aqueous liquid A or the like by the heat exchanger 29 was not performed.
As a result, when continuously operated for 12 hours, the NMP concentration in the exhaust gas C was less than 1 ppm and was stable. The results after 12 hours are shown in Table 1.

なお、表１中の圧力は、ゲージ圧を示す。

In addition, the pressure in Table 1 shows a gauge pressure.

（実施例２）
熱交換器２９に流して、水系液等Ａを冷却する冷却水の温度を７℃とした以外は、実施例１と同様にして実験を行った。その結果、排ガスＣ中のＮＭＰ量は１ｐｐｍ未満、ＮＭＰ水溶液Ｅ中のＮＭＰ濃度は８０重量％、補給水Ｄの補給量はゼロであった。 (Example 2)
An experiment was conducted in the same manner as in Example 1 except that the temperature of the cooling water for flowing the heat exchanger 29 and cooling the aqueous liquid A was 7 ° C. As a result, the NMP amount in the exhaust gas C was less than 1 ppm, the NMP concentration in the NMP aqueous solution E was 80 wt%, and the replenishment amount of the makeup water D was zero.

この発明にかかるＮＭＰ回収装置の例を示すプロセス図Process diagram showing an example of an NMP recovery apparatus according to the present invention （ａ）図１の集液装置の拡大断面図、（ｂ）（ａ）のＡ−Ａ断面図(A) Enlarged sectional view of the liquid collecting device of FIG. 1, (b) AA sectional view of (a) この発明にかかるＮＭＰ回収装置の他の例を示すプロセス図Process diagram showing another example of NMP recovery apparatus according to the present invention この発明にかかるＮＭＰ回収装置の他の例を示すプロセス図Process diagram showing another example of NMP recovery apparatus according to the present invention この発明にかかるＮＭＰ回収装置の他の例を示すプロセス図Process diagram showing another example of NMP recovery apparatus according to the present invention

Explanation of symbols

１１ａ、１１ｂ、１１ｃ、１１ｄＮＭＰ回収装置
１２、１２ａ、１２ｂ、１２ｃ吸収部
１３、１３ａ、１３ｂ、１３ｃ吸収塔
１４液貯蔵部
１５集液装置
１６吸収塔内壁
１７液溜め部
１８開口部
１９送り板 11a, 11b, 11c, 11d NMP recovery devices 12, 12a, 12b, 12c Absorber 13, 13a, 13b, 13c Absorber tower 14 Liquid reservoir 15 Liquid collector 16 Absorber tower inner wall 17 Liquid reservoir 18 Opening 19 Feed plate

２１境界壁
２２集液部
２３受け部
２４スプレー装置
２５送液配管
２６送液ポンプ
２７回収配管
２８水供給配管
２９熱交換器
３１分離フィルター 21 boundary wall 22 liquid collecting part 23 receiving part 24 spray device 25 liquid feeding pipe 26 liquid feeding pump 27 recovery pipe 28 water supply pipe 29 heat exchanger 31 separation filter

４１、４１’ 濃縮器
４２送ガス配管
４３送液配管
４４循環配管
４５回収配管
４６排ガス排出部
４７分離フィルター
４８吸収部
４９濃縮液溜め部 41, 41 'Concentrator 42 Gas supply pipe 43 Liquid supply pipe 44 Circulation pipe 45 Recovery pipe 46 Exhaust gas discharge part 47 Separation filter 48 Absorption part 49 Concentrated liquid storage part

５１スプレー装置
５２導入配管
６１、６３センサ
６２、６４，６６バルブ
６５濃度センサ 51 Spraying Device 52 Introduction Piping 61, 63 Sensor 62, 64, 66 Valve 65 Concentration Sensor

７１液接触配管
７１ａ出口
７２還流配管
７３分離フィルター
７４スプレーノズル
７５移送配管
７６，７９センサ
７７，７８バルブ 71 Liquid contact pipe 71a Outlet 72 Reflux pipe 73 Separation filter 74 Spray nozzle 75 Transfer pipe 76, 79 Sensor 77, 78 Valve

Ａ水系液等
Ｂ、Ｂ’ 同伴ガス
Ｃ排ガス
Ｄ補給水
ＥＮＭＰ水溶液
Ｆ濃縮液 A Aqueous liquid B, B 'Entrained gas C Exhaust gas D Supplementary water E NMP aqueous solution F Concentrated liquid

Claims

A plurality of absorption parts for absorbing N-methyl-2-pyrrolidone in the water or aqueous liquid by flowing a gas accompanying N-methyl-2-pyrrolidone and water or an aqueous liquid and bringing them into contact with each other. Have
This absorption part is filled with a filler,
The plurality of absorption parts are arranged in series in the vertical direction in one absorption tower, a liquid storage part is provided below the lowermost absorption part,
At the boundary between the two absorption parts, a liquid reservoir is provided at the peripheral edge of the inner wall of the absorption tower, and the part other than the liquid reservoir is opened, and water or an aqueous liquid falling from above above the opening. A feed plate for sending the liquid to the liquid reservoir, and a liquid collecting device for dropping the water or aqueous liquid overflowing from the liquid reservoir from the opening to the bottom of the absorption tower,
Provided with a liquid feed pipe for sending a part of the water or the aqueous liquid in the liquid storage part and a part or the whole of the water or the aqueous liquid in the liquid reservoir part to the absorption part directly above it,
Some water or an aqueous solution of the liquid within the reservoir, Ru provided recovery pipe for recovering the N- methyl-2-pyrrolidone absorbing solution N - methyl-2-pyrrolidone recovery device.

Arranging an absorption part similar to the above absorption part in the concentrator,
While providing a gas supply pipe for sending the exhaust gas discharged from the concentrator to the portion between the absorption section at the lowest stage of the absorption tower and the liquid storage section, a part of the water or the aqueous liquid in the liquid storage section, Provide a liquid feed pipe to be sent to the concentrator or the pipe arranged in the concentrator,
A separation filter for separating water or an aqueous liquid component contained in the exhaust gas from the exhaust gas discharged from the concentrator is provided in the exhaust gas discharge portion of the concentrator,
The N-methyl-2-pyrrolidone recovery apparatus according to claim 1 , wherein a circulation line is provided for circulating water or an aqueous liquid stored in the concentrator in the concentrator.

Water or an aqueous solution of the liquid reservoir below the absorbing portion on the top of the absorption tower, in the middle of the pipe to be sent to the absorber, according to claim 1, placing a heat exchanger for cooling the water or an aqueous solution or N- methyl-2-pyrrolidone recovery apparatus according to 2.

A part of the water or aqueous liquid in the liquid storage part of the N-methyl-2-pyrrolidone recovery device according to any one of claims 1 to 3 , and a part or all of the water or aqueous liquid in each liquid reservoir, It is sent to the absorption part directly above, and the water or aqueous liquid flows through the filling of each absorption part from the top to the bottom, and between the lowermost absorption part and the liquid storage part, Introducing a gas accompanied by N-methyl-2-pyrrolidone, and flowing this gas upward of the N-methyl-2-pyrrolidone recovery device,
A method for recovering N-methyl-2-pyrrolidone, wherein N-methyl-2-pyrrolidone accompanying the gas is absorbed in the water or aqueous liquid by bringing the water or aqueous liquid and the gas into contact with each other in the absorber. .

The water or the aqueous liquid in the concentrator of the N-methyl-2-pyrrolidone recovery apparatus according to claim 2 or 3 is circulated in the concentrator, and the N-methyl-2 is disposed above or below the concentrator. -Introducing gas accompanied by pyrrolidone,
In addition, the water in the liquid storage part in the N-methyl-2-pyrrolidone recovery device absorption tower and a part of the water or the aqueous liquid in each liquid reservoir part, or the absorption of the water or the aqueous liquid in each liquid reservoir is directly above it. And the water or aqueous liquid is allowed to flow from the upper part to the lower part through the packing of each absorption part, and is discharged from the concentrator between the lowermost absorption part and the liquid storage part. Gas is allowed to flow toward the upper side of the N-methyl-2-pyrrolidone recovery device,
A method for recovering N-methyl-2-pyrrolidone, wherein N-methyl-2-pyrrolidone accompanying the gas is absorbed in the water or aqueous liquid by bringing the water or aqueous liquid and the gas into contact with each other in the absorber. .

A plurality of absorption parts for absorbing N-methyl-2-pyrrolidone in the water or aqueous liquid by flowing a gas accompanying N-methyl-2-pyrrolidone and water or an aqueous liquid and bringing them into contact with each other. Have
This absorption part is filled with a filler,
The plurality of absorption parts are arranged in series in the vertical direction in one absorption tower, a liquid storage part is provided below the lowermost absorption part,
At the boundary between the two absorbers, and at the lower boundary between the lowermost absorber and the liquid storage part, a liquid reservoir is provided at the peripheral edge of the inner wall of the absorption tower, and a portion other than the liquid reservoir is provided. Open, and above this opening, a feed plate that sends water or aqueous liquid falling from above to the liquid reservoir is provided, and the water or aqueous liquid overflowing from the liquid reservoir provided at the boundary is Provide a liquid collecting device that drops from the opening below the absorption tower,
A separation filter is provided between the liquid reservoir provided at the lower boundary part and the liquid storage part,
A liquid contact pipe connecting the introduction pipe for supplying the gas from outside the absorption tower and the absorption tower is provided, and the liquid contact pipe includes water or an aqueous liquid supplied from a supply port provided in the interior and the gas. And having an outlet for introducing water or an aqueous liquid and the gas between the separation filter and the liquid storage part of the absorption tower,
Provide a liquid feed pipe for sending a part or all of the water or aqueous liquid in the liquid reservoir to the absorber directly above it,
A reflux pipe for supplying a part of the water or the aqueous liquid in the liquid storage part to the supply port in the liquid contact pipe is provided,
Some water or an aqueous solution of the liquid within the reservoir, providing a recovery pipe for recovering the N- methyl-2-pyrrolidone absorbing solution, N - methyl-2-pyrrolidone recovery device.

The liquid reservoir for water or an aqueous solution under the absorbing portion on the top of the absorption tower, in the middle of the pipe to be sent to the absorber, claim placing a heat exchanger for cooling the water or the aqueous solution 6 The N-methyl-2-pyrrolidone recovery device described in 1.

The N-methyl-2-pyrrolidone recovery device according to claim 6 or 7 , further comprising a transfer pipe for supplying a part of the water or the aqueous liquid in the liquid reservoir to the liquid contact pipe.

The N-methyl-2-pyrrolidone recovery device according to any one of claims 6 to 8 ,
The water or aqueous liquid sent to the absorption part is allowed to flow downward from above in the filling of the absorption part,
And while flowing the water or aqueous liquid supplied in the said liquid contact piping from the said supply port in the said liquid contact piping toward the downward direction from the upper direction, it is said N-methyl-2 from the upper direction of the said liquid contact piping. -Introducing a gas accompanied by pyrrolidone, flowing between the liquid storage part of the absorption tower and the lowermost separation filter, and flowing upwards of the absorption tower,
N-methyl-, in which the water or aqueous liquid and the gas are brought into contact with each other in the liquid contact pipe and in the absorbing portion, and the water or aqueous liquid absorbs N-methyl-2-pyrrolidone accompanying the gas. Recovery method of 2-pyrrolidone.