JP3721449B2 - Regeneration method of nitrogen dioxide absorbent - Google Patents
Regeneration method of nitrogen dioxide absorbent Download PDFInfo
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- JP3721449B2 JP3721449B2 JP32305498A JP32305498A JP3721449B2 JP 3721449 B2 JP3721449 B2 JP 3721449B2 JP 32305498 A JP32305498 A JP 32305498A JP 32305498 A JP32305498 A JP 32305498A JP 3721449 B2 JP3721449 B2 JP 3721449B2
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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Description
【０００１】
【発明の属する技術分野】
本発明は、低濃度の窒素酸化物（ＮＯｘ）を含有する例えば道路トンネルや地下閉鎖空間等の換気ガスから、二酸化窒素（ＮＯ2 ）を吸収ないしは吸着して除去する排ガス浄化装置に使用するＮＯ2 吸収ないしは吸着剤（以下、単に吸収剤という）に関し、より詳しくは、該ＮＯ2 吸収剤の再生方法に関するものである。
【０００２】
【従来の技術】
多孔質担体に、塩基性アミノ酸と有機アミン化合物および／またはアルカリ水酸化物を担持したＮＯ2 吸収剤の再生方法に関する先行技術はない。
【０００３】
【発明が解決しようとする課題】
本発明者らは、先に、多孔質担体に、塩基性アミノ酸と、有機アミン化合物および／またはアルカリ水酸化物とを担持してなるＮＯ2 吸収剤、およびこれを用いて道路トンネルの換気ガス中のＮＯ2 を吸収除去する浄化方法を提案した（特願平１０−２８８５７７）。
【０００４】
しかし、大量のＮＯ2 を吸収した吸収剤は、ＮＯ2 吸収性能が低下してしまっているので、これを適正な頻度で再生させる必要がある。
【０００５】
吸収されたＮＯ2 は主として、吸収剤表面のアミノ基と結合しているものと考えられる。加熱などの方法でこの結合を切断すれば、ＮＯ2 は脱離し吸収剤は再生されると考えられる。しかし、１００℃以上の温度での加熱は、徐々にではあるが吸収剤表面の有機化合物を分解または変質し、ＮＯ2 吸収性能の低下をもたらす。
【０００６】
また、比較例１で示すように、上記吸収剤を空気中で３００℃以上で加熱すると、塩基性アミノ酸など有機物が分解し、ＮＯ2 と同伴して脱離する。加熱処理後、再びフレッシュな有機物を担持させれば、吸収剤の再生が行える。しかし、加熱による有機物の燃焼により、細孔内が異常に高温となり、吸収剤担体の熱変化を起こし、再生後の吸収性能は大幅に低下する。
【０００７】
【課題を解決するための手段】
本発明者らは、大量にＮＯ2 を吸収した吸収剤を室温で水洗すると、ＮＯ2 と結合したままアミノ酸や有機アミンなどが溶出すること見いだした。すなわち、大量のＮＯ2 を吸収した吸収剤を水洗し、水洗水中に吸収ＮＯ2 と共に塩基性アミノ酸等などを溶出し、ついでフレッシュなアミノ酸等を担持させれば完全な再生が行えることを見いだした。
【０００８】
ここで、実施例１に示すように、空気にＮＯ2 を混合したガスに吸収剤を曝した後、再生した場合には、吸収と再生の繰り返しによる吸収剤の性能低下は全く認められなかったが、実施例２に示すように、ディーゼル排ガスに吸収剤を曝して行った同様の試験では、徐々にではあるが、吸収と再生の繰り返しによる性能低下が認められた。
【０００９】
この性能低下は、ディーゼル排ガス中に含まれる微量のオイルミストなどが吸収剤表面に蓄積されるためである。
【００１０】
実施例３に示すように、水洗処理により水溶性有機物の大半を除去した後、空気中で加熱処理を行えば、吸収と再生の繰り返しに対し、高い吸収性能を維持できる。
【００１１】
すなわち、水洗処理後に加熱処理を行えば、付着したオイルミストなど、水に不溶の成分も除去できるので、ディーゼル排ガスを用いた試験でも吸収と再生の繰り返しに起因する性能低下は起こらない。ただし、多少の熱劣化は認められる。
【００１２】
また、実施例４に示すように、水洗水に界面活性剤を添加して水洗処理を行うことにより、付着オイルミストなどを除去でき、吸収と再生の繰り返しによる吸収剤の性能低下は全く認められない。
【００１３】
本発明によるＮＯ2 吸収剤の再生方法は、多孔質担体に、塩基性アミノ酸と、有機アミン化合物および／またはアルカリ水酸化物とを担持してなる二酸化窒素吸収剤であって、二酸化窒素吸収によって劣化した吸収剤を、水洗することにより、吸収された二酸化窒素と共に塩基性アミノ酸と有機アミン化合物および／またはアルカリ水酸化物を水洗水中に溶出させ、乾燥後、再び塩基性アミノ酸と有機アミン化合物および／またはアルカリ水酸化物を担体に担持することを特徴とする方法である。
【００１４】
水洗水に界面活性剤を添加することが好ましい。
【００１５】
乾燥の代わりに、５００℃以下で空気加熱を行うことが好ましい。加熱温度が５００℃を越えると、担体がシンタリングを起こし易くなるので好ましくない。
【００１６】
加熱処理工程からの排ガスを脱硝触媒床に送り、排ガス中のＮＯｘと塩基性アミノ酸または有機アミン化合物の蒸気または熱分解物とを反応させ、ＮＯｘを無害なＮ2 とＨ2 Ｏにすることが好ましい。
【００１７】
本発明によるもう１つのＮＯ2 吸収剤の再生方法は、多孔質担体に、塩基性アミノ酸と、有機アミン化合物および／またはアルカリ水酸化物とを担持してなる二酸化窒素吸収剤であって、二酸化窒素吸収によって劣化した吸収剤を、界面活性剤と塩基性アミノ酸、有機アミン化合物および／またはアルカリ水酸化物を含む水洗水で水洗することにより、吸収した二酸化窒素を水洗水中に溶出させると同時に、塩基性アミノ酸と有機アミン化合物および／またはアルカリ水酸化物を担体に担持する方法である。
【００１８】
上記界面活性剤としては、塩基吸収剤付着オイルミストなど溶解し得る界面活性剤が好ましく、陰イオン性のラウリン酸ナトリウムなどが例示される。
【００１９】
ＮＯ2 吸収剤は、例えば、０．５〜２．０モル／リットル、好ましくは０．８〜１．５モル／リットルの塩基性アミノ酸と、０．５〜３．０当量、好ましくは０．８〜２．０当量（アミノ酸のカルボン酸に対する当量）の有機アミン化合物および／または０．５〜３．０当量、好ましくは０．８〜２．０当量（アミノ酸のカルボン酸に対する当量）のアルカリ水酸化物とを含む混合水溶液を多孔質担体に含浸させることによっても製造される。上記含浸後の多孔質担体を１５０℃以下、好ましくは１００℃以下で乾燥する。
【００２０】
多孔質担体の１つの例は、固体酸性を有する多孔質酸化物である。固体酸性を有する多孔質酸化物は、アルミナ、シリカ・アルミナ、チタニア、ゼオライト等である。これらな単独でも２以上の組み合わせでも用いられる。
【００２１】
好ましい多孔質担体は、多孔質酸化物にＭｎ、Ｃｏ、ＦｅおよびＮｉからなる群から選ばれる物質またはこれらの組合せを担持して得られる金属添加担体である。金属添加担体は、例えば、Ｍｎ、Ｃｏ、ＦｅおよびＮｉからなる群から選ばれる物質またはこれらの組合せの、硫酸塩以外の無機酸塩または有機酸塩の０．５〜５モル／リットル、好ましくは２〜４モル／リットルの水溶液を多孔質酸化物に同時または逐次に含浸させることによって得られる。
【００２２】
多孔質酸化物の比表面積は３０〜５００ｍ2 ／ｇ、好ましくは６０〜１２０ｍ2 ／ｇである。
【００２３】
多孔質酸化物は、板状またはハニカム状のプレフォーム体の繊維間の隙間に保持されていてもよい。
【００２４】
多孔質担体の他の例は活性炭である。活性炭の比表面積は１００〜２０００ｍ2 ／ｇ、好ましくは３００〜６００ｍ2 ／ｇである。
【００２５】
活性炭はハニカム状に成形することが好ましい。
【００２６】
塩基性アミノ酸としてはアルギニンが好ましく、有機アミン化合物としてはグアニジンが好ましい。アルカリ水酸化物としては、水酸化リチウム、水酸化カリウムおよび水酸化ナトリウムからなる群から選ばれる物質またはこれらの組合せが好ましい。
【００２７】
上記構成のＮＯ2 吸収剤は、これに道路トンネルの換気ガスを流速０．０５〜１０．０Ｎｍ／ｓ（空塔基準）で通し、換気ガス中のＮＯ2 を吸収除去する、道路トンネル換気ガス浄化に好適に使用される。
【００２８】
【発明の実施の形態】
（実施例１）
ａ）ＮＯ2 吸収剤の調製
０．５ｍｍ厚さのセラミックペーパー（日本無機（株）製）を波付け加工し、複数枚の波板を積層してハニカム構造体（プレフォーム体）を形成した。これを固形分濃度３０重量％のアナターゼ型チタニア（ＴｉＯ2 ）ゾルに浸漬し、ついで空気中１２０℃で乾燥した。こうして、ハニカム状チタニア担体を得た。
【００２９】
この担体を３．０モル／リットルの硝酸マンガン（Ｍｎ（ＮＯ3 ）2 ）水溶液に３０分浸漬し、ついで空気中１２０℃で乾燥し、空気通気中４５０℃で３時間焼成し、Ｍｎ添加ハニカム状チタニア担体を得た。
【００３０】
この担体を１．３モル／リットルのＬ−アルギニンと１．５モル／リットルの炭酸グアニジンの混合水溶液に３０分間浸漬した後、空気中９０℃で乾燥し、ハニカム状ＮＯ2 吸収剤を得た。
【００３１】
ｂ）固体酸担体ＮＯ2 吸収剤の性能試験
この吸収剤をステンレス製の反応器に充填し、この反応器に調製ガス（ＮＯ：０．９ｐｐｍ、ＮＯ2 ：０．１２ｐｐｍ、相対湿度：６０％）を面積速度（ＡＶ）：９ｍ／ｈの流量で通し、吸収温度は常温で、吸収剤の前流および後流においてＮＯ2 濃度を分析し、下記計算式によりＮＯ2 吸収率を計測した。これを初期の吸収率とした。
ＮＯ2 吸収率
＝［（入口ＮＯ2 濃度−出口ＮＯ2 濃度）／入口ＮＯ2 濃度］×１００
【００３２】
次に、上記吸収剤に、ＮＯ2 を含んだ空気（ボンベガス）でＮＯ2 を６Ｎリットル（ＮＯ2 ）／ｍ2 （吸収剤）吸収させた後、上記と同じくＮＯ2 吸収率を求めた。こうして得られた値を１年後相当の吸収率とした。
【００３３】
ｃ）使用済みＮＯ2 吸収剤の再生
次に、上記試験後の吸収剤を反応器から取り出し、これを常温で水洗した。この水洗により、吸収されたＮＯ2 と共にＬ−アルギニンと炭酸グアニジンを水洗水中に溶出させた。次いで、乾燥後、再び、水洗ハニカム状チタニア担体を上記と同じ操作でＬ−アルギニンと炭酸グアニジンの混合水溶液に浸漬し、９０℃乾燥して、ＮＯ2 吸収剤を得た。
【００３４】
この再生吸収剤を用い、上記と同じ条件で初期と１年後相当のＮＯ2 吸収率を求めた。さらに、この吸収と再生の操作を２０回繰り返した。５回目、１０回目、１５回目および２０回目でそれぞれ初期と１年後の吸収率を求めた。この結果を表１に示す。
【００３５】
【表１】
【００３６】
（実施例２）
実施例１で用いた、ＮＯ2 を含んだ空気（ボンベガス）の代わりに、ディーゼルエンジン排ガスでＮＯ2 を６Ｎリットル（ＮＯ2 ）／ｍ2 （吸収剤）吸収させたこと以外は、実施例１と同様の操作を行い、同条件でＮＯ2 吸収試験を行った。
【００３７】
試験結果を表２に示す。
【００３８】
【表２】
【００３９】
（実施例３）
水洗後の乾燥の代わりに、３００℃、１時間の条件で空気加熱を行ったこと以外は、実施例２と同様の操作を行い、同条件でＮＯ2 吸収試験を行った。
【００４０】
試験結果を表３に示す。
【００４１】
【表３】
【００４２】
（実施例４）
水洗水として界面活性剤（ラウリン酸ナトリウム）を含むものを用いたこと以外は、実施例２と同様の操作を行い、同条件でＮＯ2 吸収試験を行った。
【００４３】
試験結果を表４に示す。
【００４４】
【表４】
【００４５】
（実施例５）
水洗水に界面活性剤（ラウリン酸ナトリウム）とＬ−アルギニン、炭酸グアニジンを予め添加しておき、この水洗水で使用済みの吸収剤を水洗した後、９０℃で乾燥したこと以外は、実施例２と同様の操作を行い、同条件でＮＯ2 吸収試験を行った。
【００４６】
この水洗によって、吸収ＮＯ2 などを水洗水中に溶出させると同時に、水洗水中のＬ−アルギニンと炭酸グアニジンの担持を担体に担持することができた。
【００４７】
試験結果を表５に示す。
【００４８】
【表５】
【００４９】
（比較例１）
使用済み吸収剤を水洗しないで、４００℃、１時間の空気加熱を行い、再び、吸収剤をＬ−アルギニンと炭酸グアニジンの混合水溶液に浸漬し、９０℃乾燥して、再生吸収剤を得たこと以外は、実施例１と同様の操作を行い、同条件でＮＯ2 吸収試験を行った。
【００５０】
試験結果を表６に示す。
【００５１】
【表６】
【００５２】
【発明の効果】
本発明の吸収剤の再生方法によれば、使用済み吸収剤を、吸収性能の低下を起こさないで、繰り返し再生使用できる。したがって、吸収剤を交換せずに、１年以上のＮＯ2 吸収性能を発揮させることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is a NO gas used in an exhaust gas purification apparatus that absorbs or adsorbs nitrogen dioxide (NO 2 ) from a ventilation gas containing a low concentration of nitrogen oxides (NOx) such as road tunnels and underground closed spaces. 2 absorbent or adsorbent (hereinafter, simply referred to as absorber) relates, more particularly, to a reproduction method of the NO 2 absorbent.
[0002]
[Prior art]
There is no prior art relating to a method for regenerating a NO 2 absorbent in which a basic amino acid and an organic amine compound and / or an alkali hydroxide are supported on a porous carrier.
[0003]
[Problems to be solved by the invention]
The inventors of the present invention previously described a NO 2 absorbent comprising a porous carrier carrying a basic amino acid and an organic amine compound and / or an alkali hydroxide, and a ventilation gas for a road tunnel using the same. A purification method for absorbing and removing NO 2 therein was proposed (Japanese Patent Application No. 10-288877).
[0004]
However, since the absorbent that has absorbed a large amount of NO 2 has deteriorated in the NO 2 absorption performance, it must be regenerated at an appropriate frequency.
[0005]
It is considered that the absorbed NO 2 is mainly bonded to the amino group on the absorbent surface. If this bond is broken by a method such as heating, it is considered that NO 2 is desorbed and the absorbent is regenerated. However, heating at a temperature of 100 ° C. or higher gradually decomposes or alters the organic compound on the surface of the absorbent, resulting in a decrease in NO 2 absorption performance.
[0006]
Further, as shown in Comparative Example 1, when the absorbent is heated at 300 ° C. or higher in the air, organic substances such as basic amino acids are decomposed and desorbed together with NO 2 . After the heat treatment, the absorbent can be regenerated by loading fresh organic matter again. However, due to the burning of the organic matter due to heating, the inside of the pores becomes abnormally high in temperature, causing a heat change of the absorbent carrier, and the absorption performance after regeneration is greatly reduced.
[0007]
[Means for Solving the Problems]
The present inventors have found that when an absorbent that has absorbed a large amount of NO 2 is washed with water at room temperature, amino acids, organic amines and the like are eluted while bound to NO 2 . In other words, it was found that an absorbent that absorbed a large amount of NO 2 was washed with water, basic amino acids and the like were eluted together with the absorbed NO 2 in the washing water, and then a fresh amino acid and the like were supported, so that complete regeneration could be performed. .
[0008]
Here, as shown in Example 1, when the absorbent was exposed to a gas in which NO 2 was mixed with air and then regenerated, no performance degradation of the absorbent due to repeated absorption and regeneration was observed. However, as shown in Example 2, in a similar test performed by exposing the diesel exhaust gas to an absorbent, although gradually, a decrease in performance due to repeated absorption and regeneration was observed.
[0009]
This decrease in performance is due to accumulation of a small amount of oil mist and the like contained in diesel exhaust gas on the absorbent surface.
[0010]
As shown in Example 3, if most of the water-soluble organic substances are removed by washing with water and then heat treatment is performed in air, high absorption performance can be maintained with respect to repeated absorption and regeneration.
[0011]
That is, if the heat treatment is performed after the water washing treatment, water-insoluble components such as attached oil mist can be removed, so that performance deterioration due to repeated absorption and regeneration does not occur even in a test using diesel exhaust gas. However, some thermal degradation is observed.
[0012]
Further, as shown in Example 4, by adding a surfactant to the washing water and carrying out the washing treatment, it is possible to remove the adhered oil mist and the like, and the performance of the absorbent is deteriorated by repeated absorption and regeneration. Absent.
[0013]
The method for regenerating NO 2 absorbent according to the present invention is a nitrogen dioxide absorbent comprising a porous carrier carrying a basic amino acid and an organic amine compound and / or an alkali hydroxide. By washing the deteriorated absorbent with water, the basic amino acid and the organic amine compound and / or the alkali hydroxide are eluted together with the absorbed nitrogen dioxide into the washing water, and after drying, the basic amino acid and the organic amine compound and It is a method characterized in that an alkali hydroxide is supported on a carrier.
[0014]
It is preferable to add a surfactant to the washing water.
[0015]
It is preferable to perform air heating at 500 ° C. or lower instead of drying. When the heating temperature exceeds 500 ° C., the carrier tends to cause sintering, which is not preferable.
[0016]
Sending the exhaust gas from the heat treatment process to the denitration catalyst bed, reacting NOx in the exhaust gas with the vapor or thermal decomposition product of basic amino acid or organic amine compound, and converting NOx into harmless N 2 and H 2 O preferable.
[0017]
Another NO 2 absorbent regeneration method according to the present invention is a nitrogen dioxide absorbent comprising a porous carrier supporting a basic amino acid, an organic amine compound and / or an alkali hydroxide, and the carbon dioxide absorbent. The absorbent that has deteriorated due to nitrogen absorption is washed with washing water containing a surfactant and a basic amino acid, an organic amine compound and / or an alkali hydroxide to elute the absorbed nitrogen dioxide into the washing water, In this method, a basic amino acid, an organic amine compound and / or an alkali hydroxide are supported on a carrier.
[0018]
The surfactant is preferably a soluble surfactant such as a base absorbent-attached oil mist, and examples thereof include anionic sodium laurate.
[0019]
The NO 2 absorbent is, for example, 0.5 to 2.0 mol / liter, preferably 0.8 to 1.5 mol / liter of basic amino acid, 0.5 to 3.0 equivalents, preferably 0. 8 to 2.0 equivalent (equivalent of amino acid to carboxylic acid) of organic amine compound and / or 0.5 to 3.0 equivalent, preferably 0.8 to 2.0 equivalent (equivalent of amino acid to carboxylic acid) of alkali It is also produced by impregnating a porous carrier with a mixed aqueous solution containing a hydroxide. The impregnated porous carrier is dried at 150 ° C. or lower, preferably 100 ° C. or lower.
[0020]
One example of a porous carrier is a porous oxide having solid acidity. The porous oxide having solid acidity is alumina, silica / alumina, titania, zeolite or the like. These may be used alone or in combination of two or more.
[0021]
A preferred porous support is a metal-added support obtained by supporting a substance selected from the group consisting of Mn, Co, Fe and Ni or a combination thereof on a porous oxide. The metal-added carrier is, for example, a substance selected from the group consisting of Mn, Co, Fe and Ni, or a combination thereof, 0.5 to 5 mol / liter of inorganic acid salt or organic acid salt other than sulfate, preferably It is obtained by impregnating a porous oxide with a 2 to 4 mol / liter aqueous solution simultaneously or sequentially.
[0022]
The specific surface area of the porous oxide is 30 to 500 m 2 / g, preferably 60 to 120 m 2 / g.
[0023]
The porous oxide may be held in the gaps between the fibers of the plate-like or honeycomb-like preform.
[0024]
Another example of the porous carrier is activated carbon. The specific surface area of the activated carbon is 100-2000 m 2 / g, preferably from 300 to 600 m 2 / g.
[0025]
The activated carbon is preferably formed into a honeycomb shape.
[0026]
Arginine is preferable as the basic amino acid, and guanidine is preferable as the organic amine compound. As the alkali hydroxide, a substance selected from the group consisting of lithium hydroxide, potassium hydroxide and sodium hydroxide or a combination thereof is preferable.
[0027]
The NO 2 absorbent configured as described above passes the road tunnel ventilation gas at a flow rate of 0.05 to 10.0 Nm / s (empty standard) to absorb and remove NO 2 in the ventilation gas. It is suitably used for purification.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
(Example 1)
a) Preparation of NO 2 absorbent 0.5 mm thick ceramic paper (manufactured by Nippon Inorganic Co., Ltd.) was corrugated and a plurality of corrugated sheets were laminated to form a honeycomb structure (preform body). . This was immersed in anatase-type titania (TiO 2 ) sol having a solid content concentration of 30% by weight, and then dried at 120 ° C. in air. Thus, a honeycomb-like titania carrier was obtained.
[0029]
This support was immersed in an aqueous 3.0 mol / liter manganese nitrate (Mn (NO 3 ) 2 ) solution for 30 minutes, then dried at 120 ° C. in air, and fired at 450 ° C. for 3 hours in an air aeration to obtain a Mn-added honeycomb. A titania carrier was obtained.
[0030]
This support was immersed in a mixed aqueous solution of 1.3 mol / liter L-arginine and 1.5 mol / liter guanidine carbonate for 30 minutes and then dried at 90 ° C. in air to obtain a honeycomb-like NO 2 absorbent. .
[0031]
b) Performance test of solid acid carrier NO 2 absorbent This absorbent is filled into a stainless steel reactor, and the prepared gas (NO: 0.9 ppm, NO 2 : 0.12 ppm, relative humidity: 60%) is filled in this reactor. ) At a flow rate of 9 m / h, the absorption temperature was room temperature, the NO 2 concentration was analyzed in the upstream and downstream of the absorbent, and the NO 2 absorption rate was measured by the following formula. This was taken as the initial absorption rate.
NO 2 absorption rate = [(inlet NO 2 concentration−outlet NO 2 concentration) / inlet NO 2 concentration] × 100
[0032]
Next, NO 2 was absorbed into the absorbent by 6 N liters (NO 2 ) / m 2 (absorbent) with air (cylinder gas) containing NO 2 , and the NO 2 absorption rate was determined in the same manner as described above. The value thus obtained was defined as an absorption rate after one year.
[0033]
c) Regeneration of used NO 2 absorbent Next, the absorbent after the test was taken out of the reactor and washed with water at room temperature. By this washing, L-arginine and guanidine carbonate were eluted in the washing water together with the absorbed NO 2 . Next, after drying, the water-washed honeycomb titania carrier was again immersed in a mixed aqueous solution of L-arginine and guanidine carbonate by the same operation as described above, and dried at 90 ° C. to obtain a NO 2 absorbent.
[0034]
Using this regenerated absorbent, the NO 2 absorption rate corresponding to the initial and one year later was obtained under the same conditions as described above. Further, this absorption and regeneration operation was repeated 20 times. Absorption rates at the initial stage and one year later were determined at the fifth, tenth, fifteenth and twentieth times, respectively. The results are shown in Table 1.
[0035]
[Table 1]
[0036]
(Example 2)
Example 1 except that NO 2 was absorbed by 6 N liters (NO 2 ) / m 2 (absorbent) in the diesel engine exhaust gas instead of the air (cylinder gas) containing NO 2 used in Example 1. The same operation was performed, and a NO 2 absorption test was performed under the same conditions.
[0037]
The test results are shown in Table 2.
[0038]
[Table 2]
[0039]
(Example 3)
A NO 2 absorption test was performed under the same conditions as in Example 2 except that air heating was performed at 300 ° C. for 1 hour instead of drying after washing with water.
[0040]
The test results are shown in Table 3.
[0041]
[Table 3]
[0042]
(Example 4)
A NO 2 absorption test was performed under the same conditions as in Example 2 except that a washing agent containing a surfactant (sodium laurate) was used.
[0043]
The test results are shown in Table 4.
[0044]
[Table 4]
[0045]
(Example 5)
Except that surfactant (sodium laurate), L-arginine, and guanidine carbonate were previously added to the washing water, and the used absorbent was washed with this washing water and then dried at 90 ° C. The same operation as 2 was performed, and a NO 2 absorption test was performed under the same conditions.
[0046]
By this washing, absorbed NO 2 and the like were eluted in the washing water, and at the same time, L-arginine and guanidine carbonate in the washing water could be supported on the carrier.
[0047]
The test results are shown in Table 5.
[0048]
[Table 5]
[0049]
(Comparative Example 1)
Without washing the used absorbent with water, air heating was performed at 400 ° C. for 1 hour, and the absorbent was again immersed in a mixed aqueous solution of L-arginine and guanidine carbonate and dried at 90 ° C. to obtain a regenerated absorbent. Except for this, the same operation as in Example 1 was performed, and a NO 2 absorption test was performed under the same conditions.
[0050]
The test results are shown in Table 6.
[0051]
[Table 6]
[0052]
【The invention's effect】
According to the method for regenerating an absorbent of the present invention, a used absorbent can be repeatedly regenerated and used without causing a decrease in absorption performance. Therefore, NO 2 absorption performance of one year or more can be exhibited without exchanging the absorbent.
Claims (5)
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| JP32305498A JP3721449B2 (en) | 1998-11-13 | 1998-11-13 | Regeneration method of nitrogen dioxide absorbent |
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|---|---|---|---|
| JP32305498A JP3721449B2 (en) | 1998-11-13 | 1998-11-13 | Regeneration method of nitrogen dioxide absorbent |
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| JP5031244B2 (en) * | 2006-02-23 | 2012-09-19 | 三菱重工メカトロシステムズ株式会社 | How to regenerate the absorbent |
| JP4971217B2 (en) * | 2008-02-20 | 2012-07-11 | 三菱重工メカトロシステムズ株式会社 | Regeneration method of nitrogen oxide removing material |
| KR101531023B1 (en) * | 2014-05-27 | 2015-06-23 | 한국과학기술연구원 | Production method of highly strong and conductive carbon nano tube fiber by pyrolysis gas doping and carbon nano tube fiber produced thereby |
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