JP3546210B2 - Method for recovering acetic acid from wastewater containing acetic acid - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は酢酸含有排水から酢酸を回収する方法に関する。更に詳しくは、本発明は酢酸含有排水を貴金属族触媒存在下で加熱分解処理することにより、酢酸以外のＣＯＤ成分を選択的に分解し、残存する酢酸を効率良く回収する方法に関するものである。
【０００２】
【従来技術とその解決すべき課題】
一般に酢酸含有排水の処理方法には活性汚泥法、直接燃焼法が広く知られている。しかし、これらの方法はいずれも他のＣＯＤ成分と共に酢酸も処分されてしまう方法であり、有効資源のリサイクルの観点からすれば、決して好ましい方法ではない。また、余剰汚泥あるいは炭酸ガスと言った地球環境に悪影響を及ぼす物質を発生するため、地球環境保全上も好ましくない。
【０００３】
最近、実用化が進められている処理方法として湿式触媒酸化法がある。これは排水中の有機物、無機物を酸化剤の存在下に触媒的に完全酸化して分解する方法である。酢酸含有排水についても検討がなされており、これまでに特開平３−２２４６９２号、特開平７−２３２１８２号が提案されているが、これらの方法ではいずれも酢酸は大部分が炭酸ガスに分解されるため、活性汚泥法や直接燃焼法と同様に、酢酸を回収することはできない。また、特開平７−２３２１７８号には酸素含有ガス非存在下に、触媒を用いて酢酸含有排水を処理する方法が提案されているが、同様に酢酸を回収することはできない。すなわち、これまでに実用化あるいは提案されている酢酸含有排水の処理法は排水の浄化を目的としたものであり、酢酸回収を目的としたものはほとんどない。
【０００４】
酢酸回収を行う例として報告されている一つの例は蒸留回収法である。蒸留回収方法としてはオランダ国特許第７３−１６５１０号、ドイツ連邦特許第３４０８２３９ 号、ソビエト連邦特許第１２６８５６４ 号、特開平６−６５１３９ 号が提案されているが、酢酸濃度が数％以下の低濃度の場合、蒸留操作のみで効率的に排水から酢酸を回収するのは困難である。
【０００５】
また、エステル化による回収方法としてハンガリー国特許第４０９６９ 号、特開昭５９−２９６３３号が提案されている。しかし、これらの方法はエステル化と加水分解の２工程の反応を必要とし、それに伴ってアルコールの除去、水の除去などの分離操作も必要となるため、プロセス全体が長くなって設備コストが増大する。
【０００６】
その他の方法として有機溶剤による抽出法がある。酢酸抽出方法として、ホスファンオキシド（特開昭６３−４４５３９号）、アミン及び燐酸エステル（特開昭５５−１５４９３５ 号）、燐酸エステル（特開昭５７−５６００２号）などの有機溶媒を抽剤とする方法が提案されている。しかし、酢酸含有排水には一般に酢酸以外に含有される不純物が多く、これらの中から酢酸のみを選択的に抽出するのは困難である。そのため、酢酸抽出後に抽剤層から酢酸を精製する操作が必要となる。
【０００７】
また、蒸留回収、エステル化回収の場合においても同様に、排水が酢酸以外の不純物を含む場合には、酢酸の精製操作が必要となり、このことが酢酸含有排水からの酢酸回収を更に困難なものとしている。従って、例えばテレフタル酸ジメチル製造プロセスの場合、排水中には酢酸以外にギ酸、ホルムアルデヒド、メタノール等が含まれており、しかも酢酸濃度も１％〜４％と低いため、従来技術では効率的な酢酸回収は困難で、活性汚泥法、直接燃焼法等により分解処理されているのが実状である。
【０００８】
【課題を解決するための手段】
そこで、本発明者らは酢酸含有排水を処理する方法について鋭意検討を重ねた結果、酢酸含有排水を貴金属触媒存在下で加熱分解処理すると、酢酸以外の有機物をほとんど含まない酢酸含有排水が容易に得られ、酢酸回収の前処理として極めて有効であることを見い出し、本発明に至ったものである。
【０００９】
本発明は主に化学工場、製紙工場の酸化反応プロセスから排出される排水に適用できる。具体的にはアクリル酸、メタクリル酸を始めとする脂肪族カルボン酸、テレフタル酸、イソフタル酸を始めとする芳香族カルボン酸、これらカルボン酸のエステル製造プロセス等から排出される排水に対して適用できる。排水組成で規定すると、まず酢酸を含有し、それ以外にアルデヒド類、ギ酸、アルコール類のうちの少なくとも１種類を含有する排水となる。アルデヒド類は例えば、ホルムアルデヒド及びアセトアルデヒドが挙げられ、アルコール類はメタノール、エタノールが挙げられる。成分濃度は特に限定されるものではないが、酢酸濃度は排水に対しては１％以上、全有機物に対しては３０％以上が望ましい。
【００１０】
触媒は通常、金属担持型のものが用いられ、具体的にはルテニウム、パラジウム、ロジウム、及び白金よりなる群から選ばれる少なくとも１種の金属を無機酸化物あるいは活性炭に担持した固体触媒が用いられる。貴金属の担持量は触媒重量全体に対して１〜５重量％が望ましい。
【００１１】
使用可能な担体は反応雰囲気によって選択する必要がある。酸素含有ガス存在下で加熱分解処理を行う場合は、耐酸化性のある担体を使用しなければならない。したがって、一般的にはチタニア、ジルコニアが使用され、活性炭の使用はかなり制限される。一方、酸素含有ガスが存在しない場合は活性炭も使用できる。また、酢酸含有排水は一般に酸性を示すため、耐酸性のない担体、例えばアルミナの使用は控えた方がよい。
【００１２】
触媒の形状としてはペレット状、球状、ハニカム状、リング状などいずれの形態も使用できる。
【００１３】
反応温度は、１２０〜２４０℃の範囲内とすることが必要であり、１２０℃未満の低温ではギ酸、アルデヒド類、アルコール類の分解は不十分となり、処理水中に未分解の成分が残留し、高純度酢酸の効率的な回収が困難となる。また、２４０℃を越える高温では酢酸の分解反応が促進されて酢酸回収率が低下する。
【００１４】
反応圧力は１５〜３６ｋｇ ／ ｃｍ ２ Ｇの範囲とすることが必要である。
【００１５】
酸素含有ガスは空気、純酸素、酸素富化空気のいずれを用いても問題はない。
【００１６】
本発明は回分式、流通式のいずれにおいても実施することができる。
【００１７】
本発明は酸素含有ガス存在下、不存在下のいずれの条件でも行うことが出来る。
【００１８】
ギ酸、アルデヒド類、アルコール類は触媒存在下において加熱することにより、酸化、非酸化、いずれの反応でも分解されるが、後者の場合はコンプレッサーが不要となり設備コストを削減することが可能である。また酸素含有ガスを排水中に溶解させる必要がないため、前者に比べると反応圧力を低く設定できる。しかし、酸化反応に比べると分解速度が全体的に遅く、より高い反応温度を必要とする。テレフタル酸ジメチル製造プロセスの場合、排水中のメタノールは蒸留分離が容易であり、リサイクル使用も可能なので、通常メタノールを大部分除去した後の排水が処理工程に供される。但し、酸素不存在下で加熱分解を行う場合には、メタノールの分解速度が遅く、しかもホルムアルデヒドからのメタノールの生成も期待できるため、分解処理後にメタノールを蒸留回収する方が好ましい。
【００１９】
酢酸含有排水中の不純物を上記方法により加熱分解処理したのち、続いて酢酸回収が行われる。回収操作には抽出及び／又は蒸留が適用できる。抽出、蒸留をそれぞれ単独で行っても構わないし、２つの操作を組み合わせて行ってもよく、酢酸濃度に合わせて回収操作を選択するとよい。
【００２０】
抽出操作では、抽剤、抽出装置の選択を行う必要がある。酢酸抽出を行う抽剤は酢酸に対して分配係数が大きな溶剤が使用される。具体的にはメチルエチルケトン、ジエチルケトン、メチルプロピルケトン、メチルイソプロピルケトン、メチルイソブチルケトン及びメチルブチルケトンなどのケトン類、ブタノール、イソブタノール、ｔｅｒｔ−アミルアルコール及び３−ペンタノールなどのアルコール類、ギ酸ブチル、ギ酸イソプロピル、酢酸メチル、酢酸エチル、酢酸プロピル、酢酸イソプロピル、酢酸ブチル、酢酸ｓｅｃ −ブチル、酢酸ｔｅｒｔ−ブチル、酢酸ビニル、プロピオン酸メチル、プロピオン酸エチル及びブタン酸メチルなどのエステル類などが例示される。上記溶剤は少なくとも１種類以上が使用される。
【００２１】
酢酸抽出後、酢酸と溶剤との分離を効率よく行うためには、酢酸と溶剤の沸点差が少なくとも２０℃の溶剤を使用するのが好ましい。
【００２２】
抽出塔としては、通常用いられる形式、例えば、ミキサーセトラ型抽出塔、多孔板型、充填塔型、バッフル塔型、振動多孔板型、撹拌混合型、脈動充填型などが使用できる。
【００２３】
抽剤層は蒸留によって後処理するのが有利である。酢酸と抽剤との沸点差が十分あれば、通常の蒸留操作で容易に高純度酢酸を回収できる。
【００２４】
一方、排水中の酢酸濃度が充分高濃度の場合は、蒸留も効率的な方法である。
【００２５】
次に図面を参照して、本発明の実施様態を説明する。
図１は本発明における排水処理を行う装置の概略の例である。
【００２６】
まず、テレフタル酸ジメチル等の製造プラントからライン１により送液された排水は、排水供給ポンプ２により熱交換器３に送られて予熱されたのち、反応器４に供給される。ライン５から供給される酸素含有ガスはコンプレッサー６で昇圧されたのち、排水と合流して反応器４へ供給される。
【００２７】
反応器４で処理された排水はライン７より取り出され、熱交換器３で冷却されたのち、気液分離器８で気液分離された後、ライン９を経て抽出塔１１に導かれる。一方、抽剤は溶剤供給ポンプ１２によりライン１４を経て抽出塔１１に導かれる。抽出塔内部で両者が向流接触して、酢酸は抽剤層に抽出される。
【００２８】
抽出塔１１上部から抜き出された抽出後の抽剤層は、熱交換器１０に送られて予熱されたのち、抽剤層供給ポンプ１５によりライン１６を経て脱水塔１７に送られる。また、抽出塔１１下部から抜き出された水相は水層供給ポンプ１８によりライン１９を経て溶剤回収塔２０に送られる。
【００２９】
抽出後の抽剤層は脱水塔１７にて酢酸成分と水を含む抽剤成分に蒸留分離される。酢酸成分は塔底より抜き出され、酢酸成分供給ポンプ２１によりライン２２を経て酢酸塔２３に送られる。ここで酢酸は塔底から抜き出されて回収酢酸タンク２５へ回収される。一方、抽剤成分は塔頂から抜き出され、熱交換器２６で冷却されたのち、液液分離器１３から抜き出された抽剤成分と共に抽出塔１１に送られる。
【００３０】
酢酸抽出塔１１で抽出後の水層は抽剤回収塔２０で水を含む抽剤成分と処理水に分離される。処理水は抽剤回収塔塔底から抜き出され、ポンプ２７によってパージされる。
【００３１】
抽剤回収塔上部、抽剤分離塔上部から抜き出される水を含む抽剤成分はそれぞれ熱交換器２８、２９で冷却されたのち、合わせて液液分離器１３に導かれて回収抽剤と水成分に分離される。水成分は抽剤回収塔２０へ送られ、処理水とともにパージされる。また、回収抽剤はライン１４を経て酢酸抽出塔１１へ循環されて再利用される。
【００３２】
【実施例】
次に実施例を掲げて本発明を具体的に説明する。
【００３３】
［実施例１］
撹拌機を備えた内容積５００ｍＬのチタン・ライニング製オートクレーブに、外径約１ｍｍφのチタニア球上に２重量％のルテニウム（Ｒｕ）を担持させた触媒、及びギ酸、ホルムアルデヒド、酢酸を含有するＴＯＣ４７，８４０ｐｐｍの排水１００ｇを仕込み、１５０℃に昇温した。この時、オートクレーブ内圧は３ｋｇ／ｃｍ２ Ｇとなった。続いて、オートクレーブ内圧が１５ｋｇ／ｃｍ２ Ｇに到達するまで、空気を導入し、撹拌速度１０００ｒｐｍで撹拌しながら１５０℃で１時間、反応を行った。反応終了後、反応液を室温まで冷却したのち、処理水を取り出し、ガスクロマトグラフィー、等速電気泳動法により排水中の各成分を定量分析した。結果は表１に記載した通りであった。
【００３４】
［実施例２］
２重量％ロジウム−チタニア触媒を用いた以外は実験例１と同じ方法で工業排水の湿式分解テストを行った。結果は表１に記載した通りであった。
【００３５】
【表１】
［実施例３］
３Ｂ×１．１ｍＳＵＳ３１６Ｌ製の管型流通式反応器に、外径約３ｍｍφのチタニア球上に２重量％のルテニウム（Ｒｕ）を担持させた触媒５ｋｇを充填し、１９０℃まで昇温されたギ酸、ホルムアルデヒド、酢酸、メタノールを含有するＴＯＣ４７，８４０ｐｐｍの排水を重量空間速度（以後ＷＨＳＶと略称する）：２ｈｒ−１で反応器に導入した。反応条件は温度：１７８℃、圧力：２５ｋｇ／ｃｍ２ Ｇとし、４Ｎリットル／ｍｉｎの空気を反応器に導入した。処理水は連続的に取り出し、ガスクロマトグラフィー、等速電気泳動法により排水中の各成分について定量分析を行った。結果は表２に記載した通りであった。
【００３７】
［実施例４〜５］
反応温度を１４９、１５８℃、ＷＨＳＶを１ｈｒ−１に変えた以外は、実施例３と同じ方法で湿式分解テストを行った。結果は表２に記載した通りであった。
【００３８】
【表２】
［実施例６］
空気を導入しなかった以外は実験例３とほぼ同じ方法で湿式分解テストを行った。結果は表３に記載した通りであった。
【００４０】
【表３】
［実施例７］
抽出装置はプレートスタック長１０フィートの住友重機製カールカラムを用いて、実施例３で作られた処理水からの酢酸回収を行った。抽剤は酢酸エチルを用い、酢酸含有排水に対して抽剤比１．５相当の量を使用した。ストロークは２５ｍｍ一定となるようにカラム内の多孔板を上下運動させることにより、溶剤と処理水を通過速度３０ｍ３／ｍ２・Ｈで向流接触させて抽出を行った。抽剤層はカラム上部、水層はカラム下部から取り出し、ガスクロマトグラフィーにより抽剤相及び水層中の各成分を定量分析して分配組成を求めた。抽出による酢酸回収率は９７％であった。結果は表４に示した通りであった。
【００４２】
【表４】
【発明の効果】
以上述べた本発明の方法によれば、酢酸含有排水を貴金属担持触媒で加熱処理することによって、酢酸以外の有機物をほとんど含まない酢酸含有排水が容易に得られ、酢酸含有排水からの酢酸回収が容易に行えるところとなった。
【図面の簡単な説明】
【図１】第１図は本発明を実施するためのプロセス例の概略図である。
【符号の説明】
１、５、７、９、１４、１６、１９、２２は配管、
２、１２、１５、１８、２１、２４、２７、３０、３１はポンプ、
３、１０、２６、２８、２９は熱交換器、
４は反応器、
６はコンプレッサー、
８、１３は分離器、
１１は抽出塔、
１７は脱水塔、
２０は抽剤回収塔、
２３は酢酸塔および
２５は回収酢酸タンクである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for recovering acetic acid from acetic acid-containing wastewater. More specifically, the present invention relates to a method for selectively decomposing COD components other than acetic acid by subjecting acetic acid-containing waste water to thermal decomposition treatment in the presence of a noble metal group catalyst, and efficiently recovering remaining acetic acid.
[0002]
[Prior art and problems to be solved]
Generally, an activated sludge method and a direct combustion method are widely known as treatment methods for acetic acid-containing wastewater. However, all of these methods dispose acetic acid together with other COD components, which is not a preferable method from the viewpoint of recycling effective resources. In addition, since surplus sludge or carbon dioxide gas is generated, which is a substance that adversely affects the global environment, it is not preferable in terms of global environment conservation.
[0003]
Recently, there is a wet catalytic oxidation method as a treatment method which is being put to practical use. This is a method in which organic and inorganic substances in wastewater are catalytically completely oxidized and decomposed in the presence of an oxidizing agent. Studies have been made on acetic acid-containing wastewater, and Japanese Patent Application Laid-Open Nos. 3-224692 and 7-232182 have been proposed. However, in these methods, acetic acid is mostly decomposed into carbon dioxide gas. Therefore, acetic acid cannot be recovered as in the case of the activated sludge method or the direct combustion method. Japanese Patent Application Laid-Open No. Hei 7-232178 proposes a method for treating acetic acid-containing wastewater using a catalyst in the absence of an oxygen-containing gas. However, acetic acid cannot be recovered. That is, the methods of treating or discharging acetic acid-containing wastewater that have been put to practical use or proposed so far are for the purpose of purifying the wastewater, and there are few methods for recovering acetic acid.
[0004]
One example reported as performing acetic acid recovery is the distillation recovery method. As a distillation recovery method, Dutch Patent No. 73-16510, German Patent No. 3408239, Soviet Patent No. 1268564, and Japanese Patent Application Laid-Open No. 6-65139 have been proposed. In this case, it is difficult to efficiently recover acetic acid from the wastewater only by the distillation operation.
[0005]
Further, Hungarian Patent No. 40969 and JP-A-59-29633 have been proposed as recovery methods by esterification. However, these methods require a two-step reaction of esterification and hydrolysis, which also requires a separation operation such as removal of alcohol and water, thereby lengthening the entire process and increasing equipment costs. I do.
[0006]
Another method is an extraction method using an organic solvent. As an acetic acid extraction method, an organic solvent such as phosphane oxide (JP-A-63-44539), amine and phosphate ester (JP-A-55-154935), and phosphate ester (JP-A-57-56002) are used as an extractant. Has been proposed. However, acetic acid-containing wastewater generally contains many impurities other than acetic acid, and it is difficult to selectively extract only acetic acid from these impurities. Therefore, an operation of purifying acetic acid from the extractant layer after acetic acid extraction is required.
[0007]
Similarly, in the case of distillation recovery and esterification recovery, when the wastewater contains impurities other than acetic acid, a purification operation of acetic acid is required, which makes it more difficult to recover acetic acid from the acetic acid-containing wastewater. And Therefore, for example, in the case of a dimethyl terephthalate production process, wastewater contains formic acid, formaldehyde, methanol, and the like in addition to acetic acid, and the acetic acid concentration is as low as 1% to 4%. Recovery is difficult, and the fact is that it is decomposed by the activated sludge method, the direct combustion method, or the like.
[0008]
[Means for Solving the Problems]
Therefore, the present inventors have conducted intensive studies on a method for treating acetic acid-containing wastewater, and as a result, when the acetic acid-containing wastewater is thermally decomposed in the presence of a noble metal catalyst, acetic acid-containing wastewater containing almost no organic matter other than acetic acid can be easily produced. The present invention has been found to be extremely effective as a pretreatment for acetic acid recovery, leading to the present invention.
[0009]
INDUSTRIAL APPLICABILITY The present invention is mainly applicable to wastewater discharged from an oxidation reaction process in a chemical mill or a paper mill. Specifically, it can be applied to an aliphatic carboxylic acid such as acrylic acid and methacrylic acid, an aromatic carboxylic acid such as terephthalic acid and isophthalic acid, and a wastewater discharged from an ester production process of these carboxylic acids. . According to the composition of the wastewater, the wastewater first contains acetic acid and at least one of aldehydes, formic acid, and alcohols. Aldehydes include, for example, formaldehyde and acetaldehyde, and alcohols include methanol and ethanol. The component concentration is not particularly limited, but the acetic acid concentration is desirably 1% or more for wastewater and 30% or more for all organic substances.
[0010]
As the catalyst, a metal-supporting catalyst is usually used. Specifically, a solid catalyst in which at least one metal selected from the group consisting of ruthenium, palladium, rhodium, and platinum is supported on an inorganic oxide or activated carbon is used. . The loading amount of the noble metal is desirably 1 to 5% by weight based on the entire catalyst weight.
[0011]
It is necessary to select a usable carrier depending on the reaction atmosphere. When performing the thermal decomposition treatment in the presence of an oxygen-containing gas, an oxidation-resistant carrier must be used. Therefore, generally, titania and zirconia are used, and the use of activated carbon is considerably limited. On the other hand, when no oxygen-containing gas is present, activated carbon can also be used. Since acetic acid-containing wastewater generally shows acidity, it is better to refrain from using a carrier having no acid resistance, for example, alumina.
[0012]
As the shape of the catalyst, any form such as a pellet, a sphere, a honeycomb, and a ring can be used.
[0013]
The reaction temperature is required to be in the range of 120 to 240 ° C. At a low temperature of less than 120 ° C , formic acid, aldehydes, and alcohols are insufficiently decomposed, and undecomposed components remain in the treated water, Efficient recovery of high-purity acetic acid becomes difficult. At a high temperature exceeding 240 ° C., the decomposition reaction of acetic acid is accelerated, and the acetic acid recovery rate decreases.
[0014]
The reaction pressure needs to be in the range of 15 to 36 kg / cm 2 G.
[0015]
It does not matter whether the oxygen-containing gas is air, pure oxygen, or oxygen-enriched air.
[0016]
The present invention can be carried out in any of a batch type and a flow type.
[0017]
The present invention can be carried out under any conditions in the presence or absence of an oxygen-containing gas.
[0018]
Formic acid, aldehydes, and alcohols are decomposed by heating in the presence of a catalyst, regardless of whether they are oxidized or non-oxidized. However, in the latter case, a compressor is not required, and equipment costs can be reduced. Further, since it is not necessary to dissolve the oxygen-containing gas in the wastewater, the reaction pressure can be set lower than the former. However, the decomposition rate is generally slower than the oxidation reaction, and requires a higher reaction temperature. In the case of the dimethyl terephthalate production process, methanol in the wastewater can be easily separated by distillation and can be recycled, so that the wastewater from which most of the methanol has been removed is usually subjected to a treatment step. However, when heat decomposition is carried out in the absence of oxygen, the decomposition rate of methanol is slow, and the production of methanol from formaldehyde can be expected. Therefore, it is preferable to recover methanol by distillation after the decomposition treatment.
[0019]
After subjecting the impurities in the acetic acid-containing wastewater to thermal decomposition treatment by the above method, acetic acid is subsequently recovered. Extraction and / or distillation can be applied to the recovery operation. Extraction and distillation may be performed independently, or two operations may be combined, and a recovery operation may be selected according to the acetic acid concentration.
[0020]
In the extraction operation, it is necessary to select an extractant and an extraction device. As an extractant for acetic acid extraction, a solvent having a large distribution coefficient with respect to acetic acid is used. Specifically, ketones such as methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone and methyl butyl ketone, alcohols such as butanol, isobutanol, tert-amyl alcohol and 3-pentanol, butyl formate And esters such as isopropyl formate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, tert-butyl acetate, vinyl acetate, methyl propionate, ethyl propionate and methyl butanoate. Is done. At least one kind of the solvent is used.
[0021]
In order to efficiently separate acetic acid and the solvent after the acetic acid extraction, it is preferable to use a solvent having a boiling point difference of at least 20 ° C. between the acetic acid and the solvent.
[0022]
As the extraction column, a commonly used type, for example, a mixer-settler type extraction column, a perforated plate type, a packed tower type, a baffle tower type, a vibrating perforated plate type, a stirring and mixing type, a pulsating packed type, and the like can be used.
[0023]
The extractant layer is advantageously worked up by distillation. If there is a sufficient difference in boiling point between acetic acid and the extractant, high-purity acetic acid can be easily recovered by a normal distillation operation.
[0024]
On the other hand, if the concentration of acetic acid in the wastewater is sufficiently high, distillation is also an efficient method.
[0025]
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic example of an apparatus for performing wastewater treatment according to the present invention.
[0026]
First, wastewater sent from a manufacturing plant such as dimethyl terephthalate through a
[0027]
The wastewater treated in the reactor 4 is taken out from the line 7, cooled in the
[0028]
The extracted extractant layer extracted from the upper part of the
[0029]
The extractant layer after extraction is distilled and separated in the
[0030]
The aqueous layer extracted in the acetic
[0031]
The extractant components including water extracted from the upper part of the extractant recovery tower and the upper part of the extractant separation tower are cooled by the
[0032]
【Example】
Next, the present invention will be described specifically with reference to examples.
[0033]
[Example 1]
TOC47 containing a catalyst in which 2% by weight of ruthenium (Ru) was supported on titania spheres having an outer diameter of about 1 mm in an autoclave made of titanium lining having an inner volume of 500 mL and equipped with a stirrer, and TOC47 containing formic acid, formaldehyde, and acetic acid. 100 g of 840 ppm wastewater was charged and heated to 150 ° C. At this time, the internal pressure of the autoclave was 3 kg / cm 2 G. Subsequently, the reaction was carried out at 150 ° C. for 1 hour while introducing air and stirring at a stirring speed of 1000 rpm until the internal pressure of the autoclave reached 15 kg / cm 2 G. After the reaction was completed, the reaction solution was cooled to room temperature, the treated water was taken out, and each component in the waste water was quantitatively analyzed by gas chromatography and isotachophoresis. The results were as described in Table 1.
[0034]
[Example 2]
A wet cracking test of industrial wastewater was performed in the same manner as in Experimental Example 1 except that a 2% by weight rhodium-titania catalyst was used. The results were as described in Table 1.
[0035]
[Table 1]
[Example 3]
A 3B × 1.1 m SUS316L tubular flow reactor was charged with 5 kg of a catalyst having 2 wt% ruthenium (Ru) supported on titania spheres having an outer diameter of about 3 mmφ, and the temperature was raised to 190 ° C. 47,840 ppm of TOC containing water, formaldehyde, acetic acid and methanol were introduced into the reactor at a weight hourly space velocity (hereinafter abbreviated as WHSV): 2 hr -1 . The reaction conditions were as follows: temperature: 178 ° C., pressure: 25 kg / cm 2 G, and 4 N l / min of air were introduced into the reactor. The treated water was continuously taken out, and each component in the wastewater was quantitatively analyzed by gas chromatography and isotachophoresis. The results were as described in Table 2.
[0037]
[Examples 4 and 5]
A wet decomposition test was performed in the same manner as in Example 3, except that the reaction temperature was changed to 149 and 158 ° C and the WHSV was changed to 1 hr -1 . The results were as described in Table 2.
[0038]
[Table 2]
[Example 6]
A wet decomposition test was performed in substantially the same manner as in Experimental Example 3 except that no air was introduced. The results were as described in Table 3.
[0040]
[Table 3]
[Example 7]
As an extraction device, a curl column manufactured by Sumitomo Heavy Industries, Ltd. having a plate stack length of 10 feet was used to collect acetic acid from the treated water prepared in Example 3. Ethyl acetate was used as an extractant, and an amount corresponding to an extractant ratio of 1.5 relative to acetic acid-containing wastewater was used. By moving the perforated plate in the column up and down so that the stroke is constant at 25 mm, the solvent and the treated water were brought into countercurrent contact at a passage speed of 30 m 3 / m 2 · H to perform extraction. The extractant layer was taken out from the upper part of the column, and the aqueous layer was taken out from the lower part of the column. The components in the extractant phase and the aqueous layer were quantitatively analyzed by gas chromatography to determine the distribution composition. Acetic acid recovery by extraction was 97%. The results were as shown in Table 4.
[0042]
[Table 4]
【The invention's effect】
According to the method of the present invention described above, acetic acid-containing wastewater containing almost no organic matter other than acetic acid can be easily obtained by heat-treating acetic acid-containing wastewater with a noble metal-supported catalyst. It became easy to do.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an example process for practicing the present invention.
[Explanation of symbols]
1, 5, 7, 9, 14, 16, 19, and 22 are piping,
2, 12, 15, 18, 21, 24, 27, 30, 31 are pumps,
3, 10, 26, 28 and 29 are heat exchangers,
4 is a reactor,
6 is a compressor,
8, 13 are separators,
11 is an extraction tower,
17 is a dehydration tower,
20 is an extractant recovery tower,
23 is an acetic acid tower and 25 is a recovered acetic acid tank.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28735395A JP3546210B2 (en) | 1995-11-06 | 1995-11-06 | Method for recovering acetic acid from wastewater containing acetic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28735395A JP3546210B2 (en) | 1995-11-06 | 1995-11-06 | Method for recovering acetic acid from wastewater containing acetic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09122663A JPH09122663A (en) | 1997-05-13 |
| JP3546210B2 true JP3546210B2 (en) | 2004-07-21 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28735395A Expired - Fee Related JP3546210B2 (en) | 1995-11-06 | 1995-11-06 | Method for recovering acetic acid from wastewater containing acetic acid |
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| Country | Link |
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| JP (1) | JP3546210B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4643801B2 (en) * | 2000-07-05 | 2011-03-02 | 三菱瓦斯化学株式会社 | Dispersion medium replacement method and high purity terephthalic acid production method |
| KR100433826B1 (en) * | 2001-08-29 | 2004-05-31 | 한모기술주식회사 | Solvent recovery facility by the combination of extraction and distillation |
| KR100943705B1 (en) * | 2008-01-24 | 2010-02-23 | 주식회사엔아이티 | The method and system for collecting acetic/nitric acid from waste acids |
| CN104944556A (en) * | 2015-05-28 | 2015-09-30 | 中冶焦耐工程技术有限公司 | Hydrolysis reactor |
| KR20220125361A (en) * | 2020-02-26 | 2022-09-14 | 미쯔비시 케미컬 주식회사 | A method for separating a crystal containing water, a method for producing methacrylic acid, and a method for producing a methacrylic acid ester |
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1995
- 1995-11-06 JP JP28735395A patent/JP3546210B2/en not_active Expired - Fee Related
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| JPH09122663A (en) | 1997-05-13 |
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