JP4194001B2 - Acid gas treatment agent and waste gas treatment method using the same - Google Patents
Acid gas treatment agent and waste gas treatment method using the same Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、特定の方法で得られる、ＢＥＴ比表面積が大きく、かつ見掛密度が大きい水酸化カルシウムを有効成分とする酸性ガス処理剤及びそれを用いる廃ガス処理方法に関するものである。
【０００２】
【従来の技術】
ごみ焼却炉、火力発電所その他のボイラー等から生じる廃ガスは、一般に硫黄酸化物、塩化水素等の酸性ガス成分を多量に含有するため、通常はこれを廃ガス煙道中において塩基性アルカリ土類金属化合物粉体と接触させて硫酸塩や塩化物の粉体とし、これをバグフィルタ（ｂａｇ ｆｉｌｔｅｒ）や電気集塵器で分離した後にガス分を大気中に放出している。
【０００３】
ところで、一般的に廃ガス中に含まれる酸性ガス成分と水酸化カルシウムとの反応性は水酸化カルシウム粒子の表面積と相関があり、水酸化カルシウム粒子の表面積にほぼ比例して酸性ガス成分との反応性が定まるとされているが、酸性ガス処理剤として例えば市販工業用消石灰を用いた場合、この粒子のＢＥＴ比表面積は５〜２０ｍ2／ｇと小さいので、水酸化カルシウムと廃ガス中の酸性ガス成分との反応が粒子の表面でしか起こらず、酸性ガス処理剤の大部分は未反応のままダストとして排出されてしまうため、モル比で酸性ガス成分の２〜３倍量の酸性ガス処理剤を投入する必要があった。また、粉体の流動性が良好でないために、貯蔵タンク内でブリッジングを生じたり、貯蔵タンクと煙道の噴射口との間の輸送管中で閉塞を起こしやすいという問題があった。
【０００４】
このような問題を解決するために、水酸化カルシウム粒子の表面積を大きくする方法が知られているが（例えば特公平６−８１９４号公報）、得られた水酸化カルシウム製品は工業用消石灰に比べ、表面積は増大するものの、見掛密度はゆるみ見掛密度で０．２〜０．３ｇ／ｃｍ3、固め見掛密度で０．４ｇ／ｃｍ3前後と、それぞれ工業用消石灰の約０．４ｇ／ｃｍ3、約０．７ｇ／ｃｍ3より小さくなるため、重量の割には広大な貯蔵スペースを要するし、また製品使用時に貯蔵タンク出口から製品を排出するのが困難になるなど、作業性に難があった。
また、製品を陸上輸送する際にトラックやエアースライド車などの輸送用車両で輸送しているが、見掛密度が小さいため、輸送用車両に所定重量まで積載することができず、輸送コストが増大するという問題があった。
【０００５】
【発明が解決しようとする課題】
本発明は、酸性ガス処理剤における従来の問題点を解決し、酸性ガスとの反応性が向上し、廃ガス中の酸性ガス成分を効率よく除去でき、使用量の減少、貯蔵タンクからの排出時のトラブルの減少、貯蔵スペースの縮小及び輸送コストの低減を可能にし、流動性が改良されて、配管詰まりや排出不良などのトラブルが減少し、作業性が向上した水酸化カルシウムを有効成分とする酸性ガス処理剤を提供することを目的としてなされたものである。
【０００６】
【課題を解決するための手段】
本発明者らは、水酸化カルシウムを有効成分とする酸性ガス処理剤に関し、鋭意研究を重ねた結果、特定の方法で得られる所定値以上の高比表面積を有するとともに、所定値以上の大きい見掛密度を有する水酸化カルシウムを用いることにより、従来の水酸化カルシウムを有効成分とする酸性ガス処理剤がもつ欠点を克服することができ、酸性ガスとの反応性が向上し、廃ガス中の酸性ガス成分を効率よく除去できる酸性ガス処理剤が得られることを見出し、この知見に基づいて本発明を完成するに至った。
【０００７】
すなわち、本発明は、酸化カルシウムを消化して調製したＢＥＴ比表面積が少なくとも３５ｍ 2 ／ｇ以上の水酸化カルシウムを、振動ミル又はボールミル処理して粉砕と圧密造粒を同時に行わせて得られる、ＢＥＴ比表面積１４．８ｍ2／ｇ以上、ゆるみ見掛密度０．４ｇ／ｃｍ3以上、及び固め見掛密度０．７ｇ／ｃｍ3以上の水酸化カルシウムを有効成分とすることを特徴とする酸性ガス処理剤を提供するものである。
本発明処理剤の有効成分として用いられる水酸化カルシウムは、酸化カルシウムを消化してＢＥＴ比表面積が少なくとも３５ｍ2／ｇ以上の水酸化カルシウムを調製し、次いでこれを振動ミル又はボールミルにより粉砕と圧密造粒の処理を同時に施すことによって製造されるものであることが必要である。
【０００８】
【発明の実施の形態】
本発明処理剤で用いられる水酸化カルシウムはＢＥＴ比表面積及び見掛密度が共に大きい点で従来の水酸化カルシウムとは異なり、ＢＥＴ比表面積が大きいことで、反応性が向上するので、このような水酸化カルシウム粉体を使用することで、より高効率の反応が期待でき、廃ガス処理に用いて酸性ガス成分を効率よく除去するなど酸性ガスとの反応性を向上させ、また反応性の向上により使用量も減少させることが可能になる。
また、見掛密度が大きいので、貯蔵スペースを縮小したり、輸送コストを低減したりすることができる。
また、流動性も改良され、それにより配管詰まりや排出不良などのトラブルを減少させるなど、作業性を向上させることが可能になる。
【０００９】
本発明処理剤として用いる水酸化カルシウムを製造するには、先ず酸化カルシウムを消化して所定比表面積の水酸化カルシウムを調製する。この調製方法については特に制限はないが、好ましくは消化反応の際に水酸化カルシウム粒子の表面積を大きくする方法（例えば、特公平６−８１９４号公報）が挙げられ、中でもアルコールなどの消化反応を遅延させる有機溶媒の存在下に消化する方法が有利である。
酸化カルシウムは特に制限されず、石灰石を仮焼したものが一般的であるが、好ましくは乾式粉砕されたもの、例えばケージミル、バイブロミル、ボールミルなどで粉砕されたものが用いられる。
【００１０】
次いで、このようにして調製された水酸化カルシウムに、粉砕と圧密造粒を同時に行い得る能力をもつ振動ミル処理を施す。
このようにして、水酸化カルシウムはＢＥＴ比表面積４５ｍ2／ｇ以上、ゆるみ見掛密度０．４ｇ／ｃｍ3以上、固め見掛密度０．７ｇ／ｃｍ3以上になるように調製される。
ここで、ゆるみ見掛密度とは疎充填時の見掛密度を意味し、また固め見掛密度とは密充填時の見掛密度を意味する。
このような見掛密度は、原料粉体の種類、入手経路や調製手段、使用目的などにより様々に調整される。
水酸化カルシウムの各見掛密度が上記各下限値よりも小さいと、積載重量も少なくなってしまうため輸送コストが増大し、また貯蔵スペースも大きくなる。
また、水酸化カルシウムのＢＥＴ比表面積が４５ｍ2／ｇ未満では水酸化カルシウムの反応性向上効果が十分には得られない。
【００１１】
【００１２】
このような方法によって見掛密度及びＢＥＴ比表面積が大きくなるのは、見掛密度の小さい水酸化カルシウムの比較的大きな一次粒子が一度粉砕され、その後の粉砕工程中で圧密造粒作用が誘発され、該作用により一度粉砕されて生じた細かい水酸化カルシウム粒子が二次凝集を生じることで粒子が肥大化し、このような作用が繰り返されることで平均粒径が大きくなることと、このような肥大化がいったんは粉砕された上記粒子の増大した表面積を減少させないような点接着でもたらされるからであると推測される。
【００１３】
ところで、粉体の流動性の指標となる粉体物性については、例えば安息角や圧縮度などが知られているが、中でも圧縮度は粉体の流動性との関係が深いとされ、以下の式で表わされる。
Ｃ＝（Ｐ−Ａ）×１００／Ｐ
（式中のＣ、Ｐ及びＡはそれぞれ圧縮度、固め見掛密度及びゆるみ見掛密度を示す）
圧縮度が小さいほど、その粉体の流動性は良好であるとされている。
この流動性について、本発明処理剤で有効成分として用いる水酸化カルシウムを従来のそれと比べると、前者の方が良好である。この理由については必ずしも明確ではないが、粉体の流動性との関係が深い圧縮度に注目した場合、本発明処理剤で用いる水酸化カルシウムの方が従来のそれより小さくなっていることも一因であると推測される。
【００１４】
本発明の酸性ガス処理剤は、ごみ焼却炉、火力発電所その他のボイラー等の廃ガス中の酸性ガスを除去するために用いられる。
【００１５】
【実施例】
次に実施例により本発明をさらに詳細に説明するが、本発明はこれらの例によって何ら限定されるものではない。
なお、水酸化カルシウム粉体の物性は以下のようにして求めた。
（１）平均粒径：堀場製作所製の粒度分布計（ＬＡ−９２０、乾式ユニット）を用い５０％累積粒子径として求めた。
（２）見掛密度：ホソカワミクロン社製のパウダーテスタ（ＰＴ−Ｎ型）を用いて測定した。
（３）圧縮度：ホソカワミクロン社製のパウダーテスタ（ＰＴ−Ｎ型）を用いて測定した。
（４）ＢＥＴ比表面積：島津製作所製Ｆｌｏｗ Ｓｏｒｂ ＩＩ ２３００を用いて測定した。
【００１６】
まず、比較のために比較例を示す。
比較例１
ＢＥＴ比表面積１４．８ｍ2／ｇ、ゆるみ見掛密度０．４１ｇ／ｃｍ3、固め見掛密度０．７７ｇ／ｃｍ3、圧縮度４６．８％、平均粒径７．３μｍのＪＩＳ特号消石灰を酸性ガス処理剤として用い、処理能力１２０ｔ／日のごみ焼却炉の稼働時の廃ガス処理を行った。廃ガス処理塔の廃ガス煙道入口における廃ガス中の酸性成分濃度はＨＣｌが５８０ｐｐｍ、ＳＯ2が４０ｐｐｍであり、ＨＣｌとＳＯ2の入口合計量に対して酸性ガス処理剤を消石灰の量が約４当量となるような割合で噴射した。塔出口における酸性成分濃度はＨＣｌが２９ｐｐｍ、ＳＯ2が１３ｐｐｍであり、除去率はＨＣｌが９５％、ＳＯ2が６８％であった。この際の飛灰の集塵はバグフィルターで良好に行われ、また、廃ガス温度は１７５〜１８５℃であった。また、配管中における目詰まりが一時間平均で２回発生した。
【００１７】
比較例２
ＢＥＴ比表面積４３．７ｍ2／ｇ、ゆるみ見掛密度０．２５ｇ／ｃｍ3、固め見掛密度０．４６ｇ／ｃｍ3、圧縮度４５．７％、平均粒径２．８μｍの高比表面積水酸化カルシウムを酸性ガス処理剤として用い、処理能力１２０ｔ／日のごみ焼却炉の稼働時の廃ガス処理を行った。廃ガス処理塔の廃ガス煙道入口における廃ガス中の酸性成分濃度はＨＣｌが５８０ｐｐｍ、ＳＯ2が４０ｐｐｍであり、ＨＣｌとＳＯ2の入口合計量に対して酸性ガス処理剤を消石灰の量が約２当量となるような割合で噴射した。塔出口における酸性成分濃度はＨＣｌが２３ｐｐｍ、ＳＯ2が１２ｐｐｍであり、除去率はＨＣｌが９６％、ＳＯ2が７０％であった。この際の飛灰の集塵はバグフィルターで良好に行われ、また、廃ガス温度は１７５〜１８５℃であった。
また、配管中の目詰まりはなかったが、貯蔵タンク内の酸性ガス処理剤の排出が困難になるトラブルが発生した。
【００１８】
実施例１
ロータリーキルン炉で焼成され、バイブロミルで乾式粉砕された酸化カルシウム１００重量部に対して、６０重量％のエタノール水溶液９２重量部を消化液として加え、消化機中で１５分間混合後、１００℃で３０分間混合した後、熟成機に供給するとともに、熟成機内が１１０℃になるようにジャケットに加熱蒸気を導通して加熱し、熟成しながら、水及びエタノールを気化させ、さらに連続式振動ミル〔容器容積２００００ｃｍ3、媒体（ＳＵＪ−２、φ１２ｍｍ、充填率８０％）〕により加振力約７Ｇで処理し、水酸化カルシウムを得た。得られた水酸化カルシウムの粉体物性を測定したところ、ＢＥＴ比表面積４９．２ｍ2／ｇ、ゆるみ見掛密度０．５０ｇ／ｃｍ3、固め見掛密度０．７４ｇ／ｃｍ3、圧縮度３２．２％、平均粒径８．５μｍであった。
この粉体を酸性ガス処理剤として用い、処理能力１２０ｔ／日のごみ焼却炉の稼働時の廃ガス処理を行った。廃ガス処理塔の廃ガス煙道入口における廃ガス中の酸性成分濃度はＨＣｌが６４０ｐｐｍ、ＳＯ2が４５ｐｐｍであり、ＨＣｌとＳＯ2の入口合計量に対して酸性ガス処理剤を消石灰の量が約２当量となるような割合で噴射した。塔出口における酸性成分濃度はＨＣｌが１０ｐｐｍ、ＳＯ2が８ｐｐｍであり、除去率はＨＣｌが９８％、ＳＯ2が８２％であった。この際の飛灰の集塵はバグフィルターで良好に行われ、また、廃ガス温度は１７５〜１８５℃であった。
また、配管中の目詰まりはなく、貯蔵タンク内の酸性ガス処理剤の排出性は良好であった。
【００１９】
実施例２
ＢＥＴ比表面積４２．８ｍ2／ｇ、ゆるみ見掛密度０．２３ｇ／ｃｍ3、固め見掛密度０．４６ｇ／ｃｍ3、圧縮度４９．０％、平均粒径３．４μｍである市販の高比表面積水酸化カルシウムを、連続式振動ミル〔容器容積２００００ｃｍ3、媒体（ＳＵＪ−２、φ１２ｍｍ、充填率８０％）〕により加振力約７Ｇで処理した。得られた水酸化カルシウムの粉体物性を測定したところ、ＢＥＴ比表面積５０．５ｍ2／ｇ、ゆるみ見掛密度０．５８ｇ／ｃｍ3、固め見掛密度０．８７ｇ／ｃｍ3、圧縮度３３．５％、平均粒径７．１μｍであった。
この粉体を酸性ガス処理剤として用い、処理能力１２０ｔ／日のごみ焼却炉の稼働時の廃ガス処理を行った。廃ガス処理塔の廃ガス煙道入口における廃ガス中の酸性成分濃度はＨＣｌが５７０ｐｐｍ、ＳＯ2が３７ｐｐｍであり、ＨＣｌとＳＯ2の入口合計量に対して酸性ガス処理剤を消石灰の量が約２当量となるような割合で噴射した。塔出口における酸性成分濃度はＨＣｌが８ｐｐｍ、ＳＯ2が６ｐｐｍであり、除去率はＨＣｌが９９％、ＳＯ2が８４％であった。この際の飛灰の集塵はバグフィルターで良好に行われ、また、廃ガス温度は１７５〜１８５℃であった。
また、配管中の目詰まりはなく、貯蔵タンク内の酸性ガス処理剤の排出性は良好であった。
【００２０】
実施例３
ＢＥＴ比表面積４８．９ｍ2／ｇ、ゆるみ見掛密度０．２５ｇ／ｃｍ3、固め見掛密度０．４６ｇ／ｃｍ3、圧縮度４５．７％、平均粒径２．９μｍである市販の高比表面積水酸化カルシウムを、連続式振動ミル[容器容積１０００００ｃｍ3、媒体（ＳＵＪ−２、φ１２ｍｍ、充填率８０％）〕により加振力約７Ｇで処理した。得られた水酸化カルシウムの粉体物性を測定したところ、ＢＥＴ比表面積５６．７ｍ2／ｇ、ゆるみ見掛密度０．５８ｇ／ｃｍ3、固め見掛密度０．８６ｇ／ｃｍ3、圧縮度３２．６％、平均粒径８．６μｍであった。
この粉体を酸性ガス処理剤として用い、処理能力１２０ｔ／日のごみ焼却炉の稼働時の廃ガス処理を行った。廃ガス処理塔の廃ガス煙道入口における廃ガス中の酸性成分濃度はＨＣｌが６５０ｐｐｍ、ＳＯ2が３９ｐｐｍであり、ＨＣｌとＳＯ2の入口合計量に対して酸性ガス処理剤を消石灰の量が約１．８当量となるような割合で噴射した。塔出口における酸性成分濃度はＨＣｌが２０ｐｐｍ、ＳＯ2が９ｐｐｍであり、除去率はＨＣｌが９７％、ＳＯ2が７７％であった。この際の飛灰の集塵はバグフィルターで良好に行われ、また、廃ガス温度は１７５〜１８５℃であった。
また、配管中の目詰まりはなく、貯蔵タンク内の酸性ガス処理剤の排出性は良好であった。
【００２１】
【発明の効果】
本発明の酸性ガス処理剤で有効成分として用いる水酸化カルシウムは、ＢＥＴ比表面積が増大し、かつ見掛密度が大きい点で従来の水酸化カルシウムと異なり、酸性ガスとの反応性が向上し、廃ガス中の酸性ガス成分を効率よく除去でき、使用量の減少、貯蔵タンクからの排出時のトラブルの減少、貯蔵スペースの縮小及び輸送コストの低減を可能にし、流動性が改良されて、配管詰まりや排出不良などのトラブルが減少し、作業性が向上するなど種々の利点を有する。
また、本発明の酸性ガス処理剤は、ごみ焼却廃ガスなどの廃ガスから効率よく酸性ガス成分を除去でき、反応性の向上により使用量を減少させることができ、飛灰の減容化に貢献しうるという利点を有する。[0001]
BACKGROUND OF THE INVENTION
The present invention can be obtained in a particular way, BET specific surface area is large and the apparent density is related to a waste gas treatment method using an acidic gas treating agent and it as an active ingredient the calcium hydroxide has size.
[0002]
[Prior art]
Waste gas generated from waste incinerators, thermal power plants and other boilers generally contains a large amount of acidic gas components such as sulfur oxides and hydrogen chloride. It is made into a sulfate or chloride powder by contacting with a metal compound powder, and after separating it with a bag filter or an electrostatic precipitator, a gas component is released into the atmosphere.
[0003]
By the way, in general, the reactivity between the acidic gas component contained in the waste gas and calcium hydroxide correlates with the surface area of the calcium hydroxide particles, and the acid gas component is substantially proportional to the surface area of the calcium hydroxide particles. Although the reactivity is determined, for example, when commercially available slaked lime is used as an acid gas treating agent, the BET specific surface area of these particles is as small as 5 to 20 m 2 / g, so calcium hydroxide and waste gas The reaction with the acid gas component occurs only on the surface of the particles, and most of the acid gas treating agent is discharged as dust without being reacted, so that the acid gas is 2-3 times the amount of the acid gas component in molar ratio. It was necessary to add a treatment agent. In addition, since the fluidity of the powder is not good, there is a problem that bridging occurs in the storage tank or clogging is likely to occur in the transport pipe between the storage tank and the injection port of the flue.
[0004]
In order to solve such a problem, a method of increasing the surface area of calcium hydroxide particles is known (for example, Japanese Patent Publication No. 6-8194). However, the obtained calcium hydroxide product is compared with industrial slaked lime. although the surface area is increased, apparent density loose apparent density of 0.2 to 0.3 g / cm 3, and 0.4g / cm 3 back and forth in apparent density compacted, each about industrial slaked lime 0.4g / Cm 3 , smaller than about 0.7 g / cm 3 , requires a vast storage space for the weight, and makes it difficult to discharge the product from the storage tank outlet when using the product. There were difficulties.
In addition, products are transported by transportation vehicles such as trucks and air slide vehicles when transporting products on land, but because the apparent density is small, it is not possible to load the transportation vehicles up to a predetermined weight, which increases transportation costs. There was a problem of increasing.
[0005]
[Problems to be solved by the invention]
The present invention is to solve the conventional problems in the acid gas treatment agent, improved reactivity with an acidic gas, the acidic gas components in the waste gas can efficiently remove, reduce usage, emissions from storage tanks It is possible to reduce troubles at the time, reduce storage space and reduce transportation costs, improve fluidity, reduce troubles such as clogging of piping and poor discharge, and improve workability with calcium hydroxide as an active ingredient It is made for the purpose of providing the acidic gas processing agent which does.
[0006]
[Means for Solving the Problems]
As a result of intensive research on the acidic gas treating agent containing calcium hydroxide as an active ingredient , the present inventors have a high specific surface area greater than or equal to a predetermined value obtained by a specific method, and have a large appearance greater than or equal to a predetermined value. By using calcium hydroxide having a coating density , it is possible to overcome the disadvantages of conventional acid gas treatment agents containing calcium hydroxide as an active ingredient, improving the reactivity with acidic gas, The present inventors have found that an acid gas treating agent capable of efficiently removing an acid gas component can be obtained, and have completed the present invention based on this finding.
[0007]
That is, the present invention is obtained by subjecting calcium hydroxide prepared by digesting calcium oxide and having a BET specific surface area of at least 35 m 2 / g or more to vibration milling or ball milling to simultaneously perform pulverization and compaction granulation. Acidity characterized by containing calcium hydroxide having a BET specific surface area of 14.8 m 2 / g or more , a loose apparent density of 0.4 g / cm 3 or more , and a hardened apparent density of 0.7 g / cm 3 or more as an active ingredient. A gas treating agent is provided.
Calcium hydroxide used as an active ingredient of the treatment agent of the present invention is prepared by digesting calcium oxide to prepare calcium hydroxide having a BET specific surface area of at least 35 m 2 / g or more, and then pulverizing and compacting it with a vibration mill or a ball mill. It is necessary to be manufactured by carrying out the granulation treatment at the same time .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The calcium hydroxide used in the treatment agent of the present invention is different from conventional calcium hydroxide in that both the BET specific surface area and the apparent density are large, and the reactivity is improved due to the large BET specific surface area. By using calcium hydroxide powder, a more efficient reaction can be expected , and the reactivity with acidic gas is improved, such as efficient removal of acidic gas components used in waste gas treatment, and improved reactivity. This makes it possible to reduce the amount used.
Further, since the apparent density is large, the storage space can be reduced and the transportation cost can be reduced.
In addition, the fluidity is also improved, thereby making it possible to improve workability such as reducing troubles such as clogging of piping and defective discharge.
[0009]
To produce the calcium hydroxide used as the present invention the treatment agent is first calcium oxide is digested to prepare a calcium hydroxide having a predetermined specific surface area. Although there is no particular limitation on the preparation method, a method of increasing the surface area of the calcium hydroxide particles during the digestion reaction (for example, Japanese Patent Publication No. 6-8194) can be mentioned. A method of digesting in the presence of a retarding organic solvent is advantageous.
Calcium oxide is not particularly limited, and is generally calcined limestone, but is preferably dry pulverized, for example, pulverized with a cage mill, a vibro mill, a ball mill, or the like.
[0010]
Subsequently, the calcium hydroxide thus prepared is subjected to a vibration mill treatment having the ability to simultaneously perform pulverization and compaction granulation.
In this way, calcium hydroxide is prepared to have a BET specific surface area of 45 m 2 / g or more, a loose apparent density of 0.4 g / cm 3 or more, and a hardened apparent density of 0.7 g / cm 3 or more.
Here, loose means the apparent density during loosely filled and apparent density, also the solidified Apparent density refers to the apparent density during packing.
Such an apparent density is variously adjusted according to the kind of raw material powder, an acquisition route, a preparation means, a purpose of use and the like.
If each apparent density of calcium hydroxide is smaller than the above lower limit values, the load weight is reduced, so that the transportation cost is increased and the storage space is also increased .
Moreover, if the BET specific surface area of calcium hydroxide is less than 45 m 2 / g, the reactivity improvement effect of calcium hydroxide cannot be sufficiently obtained .
[0011]
[0012]
The apparent density and the BET specific surface area are increased by such a method because relatively large primary particles of calcium hydroxide having a small apparent density are pulverized once, and compaction granulation is induced in the subsequent pulverization process. The fine calcium hydroxide particles that are once pulverized by the action cause secondary agglomeration to enlarge the particles, and the repetition of such action increases the average particle size. It is presumed that the conversion is brought about by point adhesion so as not to reduce the increased surface area of the ground particles.
[0013]
By the way, with respect to the powder physical properties that serve as an index of the fluidity of the powder, for example, the angle of repose and the degree of compression are known, and among them, the degree of compression is deeply related to the fluidity of the powder. It is expressed by a formula.
C = (P−A) × 100 / P
(Shown C in the formula, each degree of compression P and A, hardened viewed apparent density and loose apparent density)
The smaller the degree of compression, the better the fluidity of the powder.
Regarding the fluidity, the former is better than the conventional calcium hydroxide used as an active ingredient in the treatment agent of the present invention. Although the reason for this is not necessarily clear, when attention is paid to the degree of compression that is deeply related to the fluidity of the powder, the calcium hydroxide used in the treatment agent of the present invention is smaller than the conventional one. It is speculated that this is the cause.
[0014]
The acid gas treating agent of the present invention is used for removing acid gas in waste gas such as garbage incinerator, thermal power plant and other boilers .
[0015]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The physical properties of the calcium hydroxide powder were determined as follows.
(1) Average particle size: 50% cumulative particle size was determined using a particle size distribution meter (LA-920, dry unit) manufactured by Horiba.
(2) Apparent density : Measured using a powder tester (PT-N type) manufactured by Hosokawa Micron.
(3) Compressibility: Measured using a powder tester (PT-N type) manufactured by Hosokawa Micron.
(4) BET specific surface area: Measured using Flow Sorb II 2300 manufactured by Shimadzu Corporation.
[0016]
First, a comparative example is shown for comparison.
Comparative Example 1
BET specific surface area of 14.8 m 2 / g, loose apparent density 0.41 g / cm 3, compacted Apparent density 0.77 g / cm 3, the compression degree of 46.8%, average particle size 7.3μm in JIS Japanese Patent slaked lime Was used as an acid gas treating agent, and a waste gas treatment was performed during operation of a waste incinerator with a treatment capacity of 120 t / day. Acidic component concentration in the waste gas in the waste gas flue inlet of the waste gas treatment tower HCl is 580 ppm, SO 2 is 40 ppm, the amount of slaked lime the acid gas processing agent with respect to the inlet total amount of HCl and SO 2 Injection was carried out at a rate such that about 4 equivalents were obtained. The concentration of acidic components at the column outlet was 29 ppm for HCl and 13 ppm for SO 2 , and the removal rates were 95% for HCl and 68% for SO 2 . At this time, the collection of fly ash was carried out satisfactorily with a bag filter, and the waste gas temperature was 175 to 185 ° C. Moreover, clogging in the piping occurred twice on average every hour.
[0017]
Comparative Example 2
BET specific surface area of 43.7m 2 / g, loose apparent density 0.25 g / cm 3, compacted Apparent density 0.46 g / cm 3, the compression degree of 45.7 percent, a high specific surface area water having an average particle diameter of 2.8μm Calcium oxide was used as an acid gas treating agent, and waste gas treatment was performed during operation of a waste incinerator with a treatment capacity of 120 t / day. Acidic component concentration in the waste gas in the waste gas flue inlet of the waste gas treatment tower HCl is 580 ppm, SO 2 is 40 ppm, the amount of slaked lime the acid gas processing agent with respect to the inlet total amount of HCl and SO 2 Injection was carried out at a rate such that it was about 2 equivalents. The concentration of acidic components at the tower outlet was 23 ppm for HCl and 12 ppm for SO 2 , and the removal rates were 96% for HCl and 70% for SO 2 . At this time, the collection of fly ash was carried out satisfactorily with a bag filter, and the waste gas temperature was 175 to 185 ° C.
Moreover, although there was no clogging in piping, the trouble which became difficult to discharge | emit the acidic gas processing agent in a storage tank occurred.
[0018]
Example 1
To 100 parts by weight of calcium oxide calcined in a rotary kiln and dry-pulverized by vibromill, 92 parts by weight of 60% by weight ethanol aqueous solution is added as a digestion solution, mixed for 15 minutes in the digester, and then at 100 ° C. for 30 minutes. After mixing, the mixture is supplied to an aging machine, heated steam is passed through the jacket so that the inside of the aging machine becomes 110 ° C., and water and ethanol are vaporized while aging, and a continuous vibration mill [container volume 20,000 cm 3 , medium (SUJ-2, φ12 mm, filling rate 80%)] with an excitation force of about 7 G to obtain calcium hydroxide. When obtained was measured powder properties of calcium hydroxide, BET specific surface area of 49.2m 2 / g, loose apparent density 0.50 g / cm 3, compacted Apparent density 0.74 g / cm 3, degree of compression 32 The average particle size was 8.5%.
Using this powder as an acid gas treatment agent, waste gas treatment was performed during operation of a waste incinerator with a treatment capacity of 120 t / day. Acidic component concentration in the waste gas in the waste gas flue inlet of the waste gas treatment tower HCl is 640 ppm, SO 2 is 45 ppm, the amount of slaked lime the acid gas processing agent with respect to the inlet total amount of HCl and SO 2 Injection was carried out at a rate such that it was about 2 equivalents. The concentration of acidic components at the column outlet was 10 ppm for HCl and 8 ppm for SO 2 , and the removal rates were 98% for HCl and 82% for SO 2 . At this time, the collection of fly ash was carried out satisfactorily with a bag filter, and the waste gas temperature was 175 to 185 ° C.
Moreover, there was no clogging in piping, and the discharge property of the acidic gas treating agent in the storage tank was good.
[0019]
Example 2
BET specific surface area 42.8 2 / g, loose apparent density 0.23 g / cm 3, compacted Apparent density 0.46 g / cm 3, the compression degree of 49.0%, commercially available high an average particle size of 3.4μm The specific surface area calcium hydroxide was treated with an excitation force of about 7 G by a continuous vibration mill (container volume 20000 cm 3 , medium (SUJ-2, φ12 mm, filling rate 80%)). When the powder physical properties of the obtained calcium hydroxide were measured, the BET specific surface area was 50.5 m 2 / g, the loose apparent density was 0.58 g / cm 3 , the solid apparent density was 0.87 g / cm 3 , and the degree of compression was 33 It was 0.5% and the average particle size was 7.1 μm.
Using this powder as an acid gas treatment agent, waste gas treatment was performed during operation of a waste incinerator with a treatment capacity of 120 t / day. The concentration of acidic components in the waste gas at the waste gas flue inlet of the waste gas treatment tower is 570 ppm for HCl and 37 ppm for SO 2. The amount of slaked lime is the amount of slaked lime with respect to the total amount of HCl and SO 2 at the inlet. Injection was carried out at a rate such that it was about 2 equivalents. The concentration of acidic components at the outlet of the tower was 8 ppm for HCl and 6 ppm for SO 2 , and the removal rates were 99% for HCl and 84% for SO 2 . At this time, the collection of fly ash was carried out satisfactorily with a bag filter, and the waste gas temperature was 175 to 185 ° C.
Moreover, there was no clogging in piping, and the discharge property of the acidic gas treating agent in the storage tank was good.
[0020]
Example 3
BET specific surface area of 48.9m 2 / g, loose apparent density 0.25 g / cm 3, compacted Apparent density 0.46 g / cm 3, the compression degree of 45.7 percent, commercial high an average particle size of 2.9μm The specific surface area calcium hydroxide was treated with an excitation force of about 7 G using a continuous vibration mill (container volume: 100,000 cm 3 , medium (SUJ-2, φ12 mm, filling rate: 80%)). When the powder physical properties of the obtained calcium hydroxide were measured, the BET specific surface area was 56.7 m 2 / g, the loose apparent density was 0.58 g / cm 3 , the solid apparent density was 0.86 g / cm 3 , and the degree of compression was 32. The average particle size was 8.6%.
Using this powder as an acid gas treatment agent, waste gas treatment was performed during operation of a waste incinerator with a treatment capacity of 120 t / day. Acidic component concentration in the waste gas in the waste gas flue inlet of the waste gas treatment tower HCl is 650 ppm, SO 2 is 39 ppm, the amount of slaked lime the acid gas processing agent with respect to the inlet total amount of HCl and SO 2 Injection was carried out at a rate such that about 1.8 equivalents were achieved. The concentration of acidic components at the tower outlet was 20 ppm for HCl and 9 ppm for SO 2 , and the removal rates were 97% for HCl and 77% for SO 2 . At this time, the collection of fly ash was carried out satisfactorily with a bag filter, and the waste gas temperature was 175 to 185 ° C.
Moreover, there was no clogging in piping, and the discharge property of the acidic gas treating agent in the storage tank was good.
[0021]
【The invention's effect】
Calcium hydroxide used as an active ingredient in the acidic gas treating agent of the present invention is different from conventional calcium hydroxide in that the BET specific surface area is increased and the apparent density is large , and the reactivity with acidic gas is improved. Acid gas components in waste gas can be removed efficiently, reducing the amount used, reducing problems when discharging from storage tanks, reducing storage space and reducing transportation costs, improving fluidity, and piping There are various advantages such as reduced troubles such as clogging and poor discharge and improved workability.
In addition, the acid gas treating agent of the present invention can efficiently remove acid gas components from waste gas such as waste incineration waste gas, can reduce the amount used by improving reactivity, and can reduce the volume of fly ash. It has the advantage of being able to contribute.
Claims (2)
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| JP22981898A JP4194001B2 (en) | 1998-08-14 | 1998-08-14 | Acid gas treatment agent and waste gas treatment method using the same |
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| JP22981898A JP4194001B2 (en) | 1998-08-14 | 1998-08-14 | Acid gas treatment agent and waste gas treatment method using the same |
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| KR20230158483A (en) | 2021-03-17 | 2023-11-20 | 쿠리타 고교 가부시키가이샤 | Combustion exhaust gas treatment method and combustion exhaust gas treatment device |
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| JP2002029738A (en) * | 2000-07-18 | 2002-01-29 | Okutama Kogyo Co Ltd | Calcium hydroxide and acidic gas treating agent by using the same |
| JP2003093837A (en) * | 2001-09-26 | 2003-04-02 | Okutama Kogyo Co Ltd | Exhaust gas treatment agent |
| JP5164051B2 (en) * | 2005-06-22 | 2013-03-13 | 北海道石灰化工株式会社 | Smoke exhaust treatment method and method for producing smoke treatment agent |
| JP4892419B2 (en) * | 2007-06-26 | 2012-03-07 | 株式会社海水化学研究所 | Calcium hydroxide compound and method for producing the same |
| JP2008255007A (en) * | 2008-05-26 | 2008-10-23 | Ube Material Industries Ltd | High reactive slaked lime |
| JP6199698B2 (en) * | 2013-11-01 | 2017-09-20 | 栗田工業株式会社 | Acid exhaust gas treatment method and exhaust gas treatment agent |
| CN114950096A (en) * | 2022-07-29 | 2022-08-30 | 大唐环境产业集团股份有限公司 | Calcium hydroxide dechlorinating agent and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20230158483A (en) | 2021-03-17 | 2023-11-20 | 쿠리타 고교 가부시키가이샤 | Combustion exhaust gas treatment method and combustion exhaust gas treatment device |
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