JP2010274195A - Iron scale sticking preventing method for converter dust collection water system and sticking inhibitor - Google Patents

Iron scale sticking preventing method for converter dust collection water system and sticking inhibitor Download PDF

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JP2010274195A
JP2010274195A JP2009129186A JP2009129186A JP2010274195A JP 2010274195 A JP2010274195 A JP 2010274195A JP 2009129186 A JP2009129186 A JP 2009129186A JP 2009129186 A JP2009129186 A JP 2009129186A JP 2010274195 A JP2010274195 A JP 2010274195A
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water
dust collection
iron
dust collector
dust
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JP5707677B2 (en
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Naohiko Murakami
直彦 村上
Shigetada Suhama
重忠 洲濱
Takeshi Toki
毅 土岐
Masahiro Mishima
将大 三嶋
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JFE Steel Corp
Kurita Water Industries Ltd
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Kurita Water Industries Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To stably operate a converter dust collection water system wherein iron scale deposits and sticks in a weak acidic condition where iron-based suspended solid is present, by surely preventing sticking of the iron-based scale by using a scale inhibitor with little adsorption of the iron-based suspended solid and consumption, and with excellent deposition preventive effect of iron ions. <P>SOLUTION: The iron scale sticking preventing method for the converter dust collection water system includes: adding 1-hydroxy ethylidene-1, 1-diphosphonic acid and/or the salt thereof to the converter dust collection water system containing 100 mg/L or more of iron-based suspended solid, with pH 7 or less, and with an iron ion concentration of 1 mg/L or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、転炉集塵水系の鉄スケール付着防止方法に係り、特に転炉集塵水系において、鉄系懸濁物質を水中に捕捉すると共に鉄イオンが溶解した後、pH上昇などにより析出する鉄系スケールの付着を有効に防止する方法に関する。   The present invention relates to a method for preventing iron scale adhesion in a converter dust collection water system, and in particular in a converter dust collection water system, iron-based suspended substances are trapped in water and iron ions are dissolved, and then precipitated due to a pH increase or the like. The present invention relates to a method for effectively preventing adhesion of an iron-based scale.

製鋼工場で発生するダストは、工場内に設置された集塵機により回収され、この回収されたダストは、鉄源として溶銑処理や転炉等で再利用されている。特に、転炉による精練工程では、酸化鉄を主体とする大量のダストが発生するため、排ガス中のCOガスを分離する方式(OG方式)の排ガス回収系統を利用した湿式集塵法によってダストの回収が行われている。   Dust generated in a steelmaking factory is collected by a dust collector installed in the factory, and the collected dust is reused as an iron source in hot metal treatment, a converter, and the like. In particular, in the scouring process using a converter, a large amount of dust, mainly iron oxide, is generated. Therefore, the dust is collected by a wet dust collection method using an exhaust gas recovery system that separates CO gas in exhaust gas (OG method). Recovery is taking place.

図1は、転炉排ガスの湿式集塵設備の一例を示す系統図であり、転炉からの排ガスは、1次集塵機2及び2次集塵機3で湿式集塵処理された後、誘導通風ファン4により吸引されて、回収弁5、水封V弁6を経てOGガスホルダ7に一時貯留され、他工場へ送られる。なお、8,9は処理ガスの流路を煙突10又はOGガスホルダ7へ調整するバイパス弁、三方弁である。   FIG. 1 is a system diagram illustrating an example of a wet dust collection facility for converter exhaust gas. After the exhaust gas from the converter is subjected to wet dust collection processing by the primary dust collector 2 and the secondary dust collector 3, an induction draft fan 4 is provided. Is temporarily stored in the OG gas holder 7 through the recovery valve 5 and the water seal V valve 6 and sent to another factory. 8 and 9 are bypass valves and three-way valves for adjusting the flow path of the processing gas to the chimney 10 or the OG gas holder 7.

1次集塵機2及び2次集塵機3には、それぞれ集塵用の水が導入され、集塵処理によりダストを含む水が排出される。各集塵機2,3の集塵排水は、循環利用されるが、その際、次のような循環方式が知られている。   Dust collecting water is introduced into the primary dust collector 2 and the secondary dust collector 3 respectively, and water containing dust is discharged by the dust collection treatment. The dust collection waste water of each of the dust collectors 2 and 3 is circulated and used, and at this time, the following circulation system is known.

(1) シリーズ給水方式
図1に示すように1次集塵機2から排出される集塵排水を水処理系統20で処理して2次集塵機3の集塵用水として給水し、2次集塵機3から排出される集塵排水を1次集塵機2の集塵用水として循環する。この場合、1次集塵機2から排出される集塵排水は、図1に示す如く、まず、粗粒分離機21で粗粒分が分離された後、シックナ23で固液分離され、分離水がOG処理水槽24を経てポンプ25により2次集塵機3に送給される。粗粒分離機21で分離された粗粒分はダストホッパ22を経て排出される。シックナ23の分離汚泥は、焼結工場等へ送給される。また、OG処理水槽24内の水の一部はオーバーフローピット26を経て系外へ排出され処理設備等へ送給される。
2次集塵機3の集塵排水はタンク27を経てポンプ28により1次集塵機2に循環される。
なお、各集塵機2,3からの集塵排水は、必要に応じて、途中、ピットやホッパ等を経て移送されるが、これらについての説明は省略する。
(1) Series water supply method As shown in FIG. 1, the dust collection wastewater discharged from the primary dust collector 2 is treated by the water treatment system 20 and supplied as dust collection water for the secondary dust collector 3 and discharged from the secondary dust collector 3. The collected dust drainage is circulated as dust collection water for the primary dust collector 2. In this case, as shown in FIG. 1, the dust collection waste water discharged from the primary dust collector 2 is first separated into coarse particles by the coarse particle separator 21, and then separated into solid and liquid by the thickener 23. The oil is fed to the secondary dust collector 3 by the pump 25 through the OG treatment water tank 24. The coarse particles separated by the coarse particle separator 21 are discharged through a dust hopper 22. The separated sludge of thickener 23 is fed to a sintering plant or the like. A part of the water in the OG treatment water tank 24 is discharged out of the system through the overflow pit 26 and is sent to the treatment facility or the like.
The dust collection waste water of the secondary dust collector 3 is circulated to the primary dust collector 2 by the pump 28 through the tank 27.
In addition, although the dust collection waste_water | drain from each dust collector 2 and 3 is transferred on the way through a pit, a hopper, etc. as needed, description about these is abbreviate | omitted.

(2) パラレル給水方式
1次集塵機2から排出される集塵排水を水処理して1次集塵機2の集塵用水として循環し、2次集塵機3から排出される集塵排水を水処理して2次集塵機3の集塵用水として循環する。
この場合、1次集塵機2の集塵排水と2次集塵機3の集塵排水は、図1に示すような水処理系統に送給されて処理され、処理水がそれぞれ1次集塵機2及び2次集塵機3に集塵用水として送給される。
(2) Parallel water supply system Drainage drainage discharged from the primary dust collector 2 is treated with water and circulated as dust collection water for the primary dust collector 2, and dust collection wastewater discharged from the secondary dust collector 3 is treated with water. It circulates as dust collection water for the secondary dust collector 3.
In this case, the dust collection waste water of the primary dust collector 2 and the dust collection waste water of the secondary dust collector 3 are sent to a water treatment system as shown in FIG. 1 and processed, and the treated water is respectively treated with the primary dust collector 2 and the secondary dust collector. It is supplied to the dust collector 3 as dust collecting water.

このような転炉集塵水系では、次のような要因で鉄スケールの析出、付着の問題があった。   In such a converter dust collection water system, there was a problem of precipitation and adhesion of iron scale due to the following factors.

転炉集塵水は、吹錬時に酸化鉄や鉄を主体とするダストを捕捉すると同時に、炭酸ガスを吸収してpHが低下する。pH低下(pH6〜7或いはそれ以下)により鉄がイオンとして溶解するが、徐々に炭酸ガスを放出してpHが上昇すると同時に鉄溶解度が下がるため、鉄の析出が起こる。即ち、FeイオンはpH上昇に伴い溶解度が小さくなり、また、Feイオンの中でもFe2+は不安定なため、より溶解度の小さいFe3+に酸化され易いことから、鉄の析出、付着が起こる。この鉄の析出、付着の際、共存する鉄系懸濁物質を抱き込むことにより系内のスケール付着が増大する。集塵系内にスケールが付着すると、集塵水量が低下するため、集塵効率が低下し、著しい場合には操業停止に至る場合がある。 Converter dust collection water captures dust mainly composed of iron oxide and iron during blowing, and simultaneously absorbs carbon dioxide gas to lower the pH. Iron is dissolved as ions by lowering the pH (pH 6 to 7 or less), but since the carbon solubility is gradually released by releasing carbon dioxide gradually, the iron solubility decreases, so that iron precipitation occurs. That is, Fe ions become less soluble with increasing pH, and among Fe ions, Fe 2+ is unstable, and is easily oxidized to Fe 3+ having a lower solubility, so that precipitation and adhesion of iron occur. In the deposition and adhesion of iron, the adhesion of scales in the system is increased by embedding the coexisting iron-based suspended matter. If the scale adheres to the dust collection system, the amount of collected water decreases, so that the dust collection efficiency decreases, and in some cases, the operation may be stopped.

従来、水系の鉄系スケールの防止方法としては、ホスホン酸系、アクリル酸系、或いはマレイン酸系の重合物や共重合物をスケール防止剤として添加することが行われてきた。   Conventionally, as a method for preventing an aqueous iron-based scale, a phosphonic acid-based, acrylic acid-based, or maleic acid-based polymer or copolymer has been added as a scale inhibitor.

また、水系に添加されたスケール防止剤は、その水系に懸濁物質が存在すると、その懸濁物質に吸着、消耗され、目的とする効果が得られないことが知られている。例えば、特許文献1には、鉄化合物や懸濁物質が存在する水系では、従来のスケール防止剤を添加しても十分な効果が得られないため、スケール防止剤を添加する水系の全鉄濃度(鉄イオン・コロイド・粒子の合計量)を1mg/L以下に制御する必要があることが報告されている。   In addition, it is known that the scale inhibitor added to the aqueous system is adsorbed and consumed by the suspended material when the suspended material is present in the aqueous system, and the intended effect cannot be obtained. For example, Patent Document 1 discloses that in an aqueous system in which an iron compound or a suspended substance exists, even if a conventional scale inhibitor is added, a sufficient effect cannot be obtained. It has been reported that it is necessary to control (total amount of iron ions, colloids, and particles) to 1 mg / L or less.

しかしながら、従来においては、鉄系懸濁物質存在下での鉄イオンの析出が原因で鉄系スケールが付着する系に対して、有効なスケール付着防止技術の提案はなされていない。このため、前述の転炉集塵水系における鉄スケールの析出、付着については、定期的に運転を停止して、配管内洗浄や配管交換を行うことで対応しており、このことが、安定操業に支障を来していた。   However, conventionally, an effective scale adhesion prevention technique has not been proposed for a system in which iron-based scales adhere due to precipitation of iron ions in the presence of iron-based suspended solids. For this reason, precipitation and adhesion of iron scale in the converter dust collection water system described above can be handled by periodically stopping the operation and cleaning the pipe or replacing the pipe. Had a problem.

特開2008−6369号公報JP 2008-6369 A

本発明は、鉄系懸濁物質が存在する弱酸性条件下で鉄スケールが析出、付着する転炉集塵水系において、鉄系懸濁物質に対する吸着、消耗が少なく且つ鉄イオンの析出抑制効果に優れたスケール防止剤を用いて、鉄系スケールの付着を確実に防止して安定操業を図る転炉集塵水系の鉄スケール付着防止方法を提供することを目的とする。   In the converter dust collection water system in which iron scale deposits and adheres under weakly acidic conditions in which iron-based suspended solids exist, the present invention reduces adsorption and consumption of iron-based suspended solids, and suppresses the precipitation of iron ions. An object of the present invention is to provide an iron scale adhesion prevention method for a converter dust collection water system that reliably prevents the adhesion of an iron-based scale by using an excellent scale preventive agent and performs stable operation.

本発明(請求項1)の転炉集塵水系の鉄スケール付着防止方法は、鉄系懸濁物質が100mg/L以上存在し、pH7以下、鉄イオン濃度が1mg/L以上である転炉集塵水系に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加することを特徴とする。   According to the present invention (Claim 1), the converter dust collection water system iron scale adhesion prevention method is a converter collection in which iron-based suspended substances are present at 100 mg / L or more, pH is 7 or less, and iron ion concentration is 1 mg / L or more. 1-Hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is added to the dust water system.

請求項2の転炉集塵水系の鉄スケール付着防止方法は、請求項1において、前記鉄系懸濁物質が、FeO、Fe、Fe、Fe、及びFeO(OH)よりなる群から選ばれる1種又は2種以上を主成分とすることを特徴とする。 The converter dust collection water system iron scale adhesion preventing method according to claim 2 is the method of claim 1, wherein the iron-based suspended substance is FeO, Fe 2 O 3 , Fe 3 O 4 , Fe, and FeO (OH). The main component is one or more selected from the group consisting of:

請求項3の転炉集塵水系の鉄スケール付着防止方法は、前記転炉集塵水系が、転炉排ガスを1次集塵機及び2次集塵機で順次集塵処理している集塵水系であって、1次集塵機から排出される集塵排水を水処理した後、2次集塵機の集塵用水として給水し、2次集塵機から排出される集塵排水を1次集塵機の集塵用水として循環するシリーズ給水の集塵方式においては、2次集塵機から排出され1次集塵機に循環される循環水及び/又は1次集塵機から排出され水処理後に2次集塵機に給水される処理水に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加し、1次集塵機から排出される集塵排水を水処理した後、1次集塵機の集塵用水として循環し、2次集塵機から排出される集塵排水を水処理した後、2次集塵機の集塵用水として循環するパラレル給水の集塵方式においては、1次集塵機から排出され水処理後に1次集塵機に循環される循環水及び/又は2次集塵機から排出され水処理後に2次集塵機に循環される循環水に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加することを特徴とする。   The converter dust collection water system iron scale adhesion prevention method according to claim 3 is a dust collection water system in which the converter dust collection water system sequentially collects dust from the converter exhaust gas by a primary dust collector and a secondary dust collector. Series in which the dust collection wastewater discharged from the primary dust collector is treated with water, then supplied as the dust collection water for the secondary dust collector, and the dust collection wastewater discharged from the secondary dust collector is circulated as the dust collection water for the primary dust collector. In the dust collection system for water supply, 1-hydroxyethylidene is used as circulating water discharged from the secondary dust collector and circulated to the primary dust collector and / or treated water supplied from the primary dust collector to the secondary dust collector after water treatment. -1,1-diphosphonic acid and / or its salt is added and the wastewater discharged from the primary dust collector is treated with water, and then circulated as dust collection water for the primary dust collector and discharged from the secondary dust collector. After the dust collection wastewater is treated with water, the secondary dust collector In the dust collection system that circulates as water for dust collection, circulating water discharged from the primary dust collector and circulated to the primary dust collector after water treatment and / or discharged from the secondary dust collector and recycled to the secondary dust collector after water treatment 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is added to the circulating water.

請求項4の転炉集塵水系の鉄スケール付着防止方法は、請求項1ないし3のいずれか1項において、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を、転炉集塵水系における濃度が0.1〜100mg/Lとなるように添加することを特徴とする。   A method for preventing iron scale adhesion in a converter dust collection water system according to claim 4 is the method according to any one of claims 1 to 3, wherein 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is converted into the converter collection. It adds so that the density | concentration in a dust water system may be 0.1-100 mg / L.

本発明(請求項5)の転炉集塵水系の鉄スケール付着防止剤は、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を含むことを特徴とする。   The iron scale adhesion inhibitor of the converter dust collection water system of the present invention (Claim 5) is characterized by containing 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof.

1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩(以下「1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)」と称す場合がある。)は、鉄系懸濁物質が存在する系において、懸濁物質に対する吸着及びそれによる消耗が少なく、しかも鉄イオンの析出抑制効果に優れ、鉄系懸濁物質が100mg/L以上存在し、かつpH7以下で鉄イオン濃度が1mg/L以上の鉄が析出し易い転炉集塵水系において、鉄スケールの析出及び付着を有効に防止する。   1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof (hereinafter sometimes referred to as “1-hydroxyethylidene-1,1-diphosphonic acid (salt)”) contains an iron-based suspended substance. In this system, the adsorption to the suspended substance and the consumption due thereto are small, and the iron ion precipitation suppression effect is excellent, the iron-based suspended substance is present at 100 mg / L or more, and the iron ion concentration is 1 mg / L at pH 7 or less. In the converter dust collection water system in which the above iron is likely to precipitate, precipitation and adhesion of iron scale are effectively prevented.

なお、カルシウム系の懸濁物質の存在下では、懸濁物質表面のCaとホスホン酸との吸着或いはホスホン酸カルシウムの生成によりホスホン酸系化合物である1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)は消耗する。しかしながら、本発明で対象とする転炉集塵水系中の鉄系懸濁物質の場合は、1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)の吸着が少なく、吸着、消耗によるスケール付着防止効果の低下は防止され、添加効果を有効に発揮することができる。   In the presence of a calcium-based suspended substance, 1-hydroxyethylidene-1,1-diphosphonic acid, which is a phosphonic acid compound, is formed by adsorption of Ca and phosphonic acid on the surface of the suspended substance or generation of calcium phosphonate. Salt) is consumed. However, in the case of the iron-based suspended matter in the converter dust collection water system targeted by the present invention, the adsorption of 1-hydroxyethylidene-1,1-diphosphonic acid (salt) is small, and the scale adhesion due to adsorption and consumption is prevented. Reduction of the effect is prevented, and the effect of addition can be exhibited effectively.

このため、本発明によれば、転炉集塵水系における鉄イオンの析出、付着による集塵効率の低下を防止し、また配管洗浄や配管交換の頻度を大幅に低減して、安定操業を図ることが可能となる。   Therefore, according to the present invention, it is possible to prevent a decrease in dust collection efficiency due to precipitation and adhesion of iron ions in the converter dust collection water system, and to greatly reduce the frequency of pipe cleaning and pipe replacement to achieve stable operation. It becomes possible.

転炉排ガスの湿式集塵設備の一例を示す系統図である。It is a systematic diagram which shows an example of the wet dust collection equipment of converter exhaust gas.

以下に本発明の転炉集塵水系の鉄スケール付着防止方法の実施の形態を詳細に説明する。   Embodiments of an iron scale adhesion prevention method for a converter dust collection water system according to the present invention will be described in detail below.

本発明の転炉集塵水系の鉄スケール付着防止方法においては、転炉集塵水系に対して鉄スケールの付着防止剤として、1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加する。このうち1−ヒドロキシエチリデン−1,1−ジホスホン酸の塩としては、1−ヒドロキシエチリデン−1,1−ジホスホン酸のナトリウム塩、カリウム塩などのアルカリ金属塩やアンモニウム塩などを用いることができ、この塩は一つのホスホン酸基のみが塩形となったものであっても、二つのホスホン酸基が塩形となったものでも良い。1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)は1種を単独で用いても良く、2種以上を混合して用いても良い。   In the converter dust collection water system iron scale adhesion prevention method of the present invention, 1-hydroxyethylidene-1,1-diphosphonic acid (salt) is added as an iron scale adhesion prevention agent to the converter dust collection water system. . Among these, as a salt of 1-hydroxyethylidene-1,1-diphosphonic acid, alkali metal salts such as sodium salt and potassium salt of 1-hydroxyethylidene-1,1-diphosphonic acid, ammonium salts, and the like can be used. This salt may be one in which only one phosphonic acid group is in a salt form, or may be one in which two phosphonic acid groups are in a salt form. 1-hydroxyethylidene-1,1-diphosphonic acid (salt) may be used alone or in combination of two or more.

本発明において処理対象とする転炉集塵水系は、鉄系懸濁物質を100mg/L以上を含み、pHが7以下の酸性条件であり、鉄イオン濃度が1mg/L以上の水系である。   The converter dust collection water system to be treated in the present invention is an aqueous system containing 100 mg / L or more of an iron-based suspended substance, an acidic condition having a pH of 7 or less, and an iron ion concentration of 1 mg / L or more.

このうち鉄系懸濁物質は、一般に、FeO、Fe、Fe等の酸化鉄、金属鉄、FeO(OH)等の水酸化鉄といった鉄系成分を主体とし、通常これらの鉄系成分を60重量%以上含むものである。
転炉集塵水系中の鉄系懸濁物質の存在量は、通常100mg/L以上、特に500mg/L以上である。鉄系懸濁物質の存在量の上限には特に制限はないが、通常10,000mg/L以下である。このような鉄系懸濁物質存在量の転炉集塵水系は、通常濁度が20度以上、例えば50〜90度の高濁度懸濁水である。
Of these, iron-based suspended substances are generally composed mainly of iron-based components such as iron oxides such as FeO, Fe 2 O 3 , and Fe 3 O 4 , metal iron, and iron hydroxide such as FeO (OH). It contains 60% by weight or more of iron-based components.
The abundance of the iron-based suspended matter in the converter dust collection water system is usually 100 mg / L or more, particularly 500 mg / L or more. Although there is no restriction | limiting in particular in the upper limit of the abundance of an iron-type suspended solid, Usually, it is 10,000 mg / L or less. The converter dust collection water system having such iron-based suspended solids is usually highly turbid suspended water having a turbidity of 20 degrees or more, for example, 50 to 90 degrees.

また、転炉集塵水系のpHは、炭酸ガスの放出量によっても異なるが、通常pH6〜7、特に6.5〜7程度であり、このような弱酸性の転炉集塵水系内では、その後の炭酸ガスの放出によるpH上昇で鉄イオンの析出がおこる。   In addition, the pH of the converter dust collection water system varies depending on the amount of carbon dioxide released, but is usually about pH 6 to 7, particularly about 6.5 to 7. In such a weakly acidic converter dust collection water system, Thereafter, precipitation of iron ions occurs due to the increase in pH due to the release of carbon dioxide gas.

また、転炉集塵水系の鉄イオン濃度は通常1mg/L以上であり、その上限は通常100mg/L以下である。本発明においては、10mg/L以上特に20mg/L以上の高濃度の鉄イオンが存在する場合でも有効に鉄スケールの付着を防ぐことができる。   Moreover, the iron ion concentration of a converter dust collection water system is 1 mg / L or more normally, and the upper limit is 100 mg / L or less normally. In the present invention, even when a high concentration of iron ions of 10 mg / L or more, particularly 20 mg / L or more is present, adhesion of iron scale can be effectively prevented.

本発明においては、このように鉄系懸濁物質が多量に存在し、かつ鉄イオン濃度の高い、弱酸性の、鉄イオンが析出し易い転炉集塵水系に、1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加することにより、鉄スケールの析出、付着を防止する。   In the present invention, a 1-hydroxyethylidene-1, 1-hydroxyethylidene-1, in a converter dust collection water system in which a large amount of iron-based suspended substances are present and the iron ion concentration is high and weakly acidic and iron ions easily precipitate. By adding 1-diphosphonic acid (salt), precipitation and adhesion of iron scale are prevented.

転炉集塵水系への1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)の添加量は、鉄スケールの付着防止効果が得られる程度であれば良く、転炉集塵水系の水質による鉄スケールの析出傾向によっても異なるが、通常、処理対象水中の1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)濃度が0.1〜100mg/L、特に1〜10mg/Lとなるように添加することが好ましい。1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)添加量が少な過ぎると十分なスケール付着防止効果を得ることができず、多過ぎても添加効果に見合う向上効果は得られず、薬剤コストの面で経済的に不利である。   The amount of 1-hydroxyethylidene-1,1-diphosphonic acid (salt) added to the converter dust collection water system only needs to be sufficient to prevent the adhesion of the iron scale. Usually, added so that the concentration of 1-hydroxyethylidene-1,1-diphosphonic acid (salt) in the water to be treated is 0.1 to 100 mg / L, particularly 1 to 10 mg / L, although it varies depending on the scale precipitation tendency. It is preferable to do. If the amount of 1-hydroxyethylidene-1,1-diphosphonic acid (salt) added is too small, a sufficient scale adhesion preventing effect cannot be obtained. This is economically disadvantageous.

1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)の添加箇所としては特に制限はないが、前述の集塵方式に応じて、例えば次のような箇所とすることが好ましい。   Although there is no restriction | limiting in particular as an addition location of 1-hydroxy ethylidene-1, 1- diphosphonic acid (salt), For example, it is preferable to set it as the following locations according to the above-mentioned dust collection system.

(1) シリーズ給水の集塵方式の場合
2次集塵機から排出され1次集塵機に循環される循環水及び/又は1次集塵機から排出され水処理後に2次集塵機に給水される処理水に添加する。
例えば、図1において、1次集塵機2へ循環される2次集塵機3の集塵排水、及び/又は1次集塵機2の集塵排水を水処理系統20で処理した後、2次集塵機3に給水される集塵用水に、1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加する。
(1) In the case of series water collection dust collection system Add to circulating water discharged from the secondary dust collector and circulated to the primary dust collector and / or treated water supplied from the primary dust collector to the secondary dust collector after water treatment .
For example, in FIG. 1, the dust collection wastewater of the secondary dust collector 3 circulated to the primary dust collector 2 and / or the dust collection wastewater of the primary dust collector 2 is treated by the water treatment system 20 and then the secondary dust collector 3 is supplied with water. 1-hydroxyethylidene-1,1-diphosphonic acid (salt) is added to the collected water.

(2) パラレル給水の集塵方式の場合
1次集塵機から排出され水処理後に1次集塵機に循環される循環水、及び/又は、2次集塵機から排出され水処理後に2次集塵機に循環される循環水に添加する。
(2) In the case of parallel water supply dust collection system Circulating water discharged from the primary dust collector and circulated to the primary dust collector after water treatment and / or discharged from the secondary dust collector and circulated to the secondary dust collector after water treatment Add to circulating water.

即ち、本発明では、集塵機に対して集塵用水として給水される水に対して1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加することが好ましく、特に、前段側の1次集塵機に集塵用水として給水される水に1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加することが好ましく、これにより、鉄系懸濁物質を多く含み、また転炉排ガスと接触した直後であるため炭酸成分を多く含み、pHが上昇する前の系内で1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)によるスケール析出防止効果を効果的に発揮させることができる。   That is, in the present invention, it is preferable to add 1-hydroxyethylidene-1,1-diphosphonic acid (salt) to water supplied as dust collecting water to the dust collector, and in particular, the primary dust collector on the front stage side. It is preferable to add 1-hydroxyethylidene-1,1-diphosphonic acid (salt) to the water supplied as dust collection water, so that it contains a lot of iron-based suspended solids and is in contact with the converter exhaust gas. Since it is immediately after that, it contains a large amount of carbonic acid component, and the effect of preventing the precipitation of scale by 1-hydroxyethylidene-1,1-diphosphonic acid (salt) can be effectively exhibited in the system before the pH rises.

なお、このような転炉集塵水系への1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)の添加にあたり、1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)は配管にライン注入しても良く、また、適当なピットやタンクに添加しても良い。また、給水ポンプの入口側で添加して、ポンプ内での攪拌効果を得ることも好ましい態様である。
例えば、図1におけるシリーズ給水の集塵方式の場合、2次集塵機3からの集塵排水を受けるタンク27に添加することにより、薬注作業が容易であると共に、添加した1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を集塵水中に均一に溶解させることができ好ましい。
In addition, when 1-hydroxyethylidene-1,1-diphosphonic acid (salt) is added to such a converter dust collection water system, 1-hydroxyethylidene-1,1-diphosphonic acid (salt) is injected into the piping. It may be added to an appropriate pit or tank. Moreover, it is also a preferable aspect that it is added at the inlet side of the water supply pump to obtain a stirring effect in the pump.
For example, in the case of the series water collection dust collection system in FIG. 1, the addition of 1-hydroxyethylidene-1 added to the tank 27 that receives the dust collection wastewater from the secondary dust collector 3 is easy and the chemical injection operation is easy. , 1-Diphosphonic acid (salt) is preferable because it can be uniformly dissolved in the dust collection water.

ただし、本発明は、図1に示すように、1次集塵機と2次集塵機の2機の集塵機で集塵処理する場合に何ら限定されず、1機の集塵機で集塵処理する場合であっても、当該集塵機の集塵用水に1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加して良好なスケール析出防止効果を得ることができる。   However, as shown in FIG. 1, the present invention is not limited to the case where dust collection processing is performed by two dust collectors, a primary dust collector and a secondary dust collector, and is a case where dust collection processing is performed by one dust collector. In addition, 1-hydroxyethylidene-1,1-diphosphonic acid (salt) can be added to the dust collecting water of the dust collector to obtain a good scale precipitation preventing effect.

また、集塵機には、集塵排水を処理して循環使用する循環水の他、補給水として、系外から工業用水等を導入する場合があるが、この場合、この補給水に1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)を添加して、鉄系懸濁物質が100mg/L以上存在し、pH7以下、鉄イオン濃度が1mg/L以上である転炉集塵水系に1−ヒドロキシエチリデン−1,1−ジホスホン酸(塩)が添加されるようにすることもできる。   In addition to the circulating water used to treat and circulate the dust collection wastewater, industrial water or the like may be introduced from outside the system into the dust collector. In this case, 1-hydroxyethylidene is added to the makeup water. -1,1-diphosphonic acid (salt) is added, and iron-suspended material is present at 100 mg / L or more, pH 7 or less, and iron ion concentration is 1 mg / L or more in the converter dust collection water system. Ethylidene-1,1-diphosphonic acid (salt) can also be added.

以下に実施例、比較例及び参考例を挙げて本発明をより具体的に説明する。   Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples.

[机上試験]
1) 模擬試験水の調製
野木町水に鉄系懸濁物質として市販のFeO試薬(粒子径75μm以下)を1000mg/L添加して攪拌し、pHを塩酸で6.5に調整して模擬試験水Aを調製した。
比較のためにFeO試薬を無添加で、pHのみ6.5とした模擬試験水Bを調製した。
[Desktop test]
1) Preparation of simulated test water 1000 mg / L of a commercially available FeO reagent (particle size of 75 μm or less) as an iron-based suspended substance is added to Nogi-cho water and stirred, and the pH is adjusted to 6.5 with hydrochloric acid for a simulated test. Water A was prepared.
For comparison, simulated test water B was prepared with no FeO reagent added and only pH of 6.5.

2) 試験方法
模擬試験水A及びBにそれぞれ、表1示す薬剤を添加した後(ただし、比較例1,4では薬剤無添加)、硫酸第一鉄を鉄イオン(Fe2+)濃度が3mg/Lとなるように添加して10分間攪拌した。この液を0.1μmマイクロフィルターで濾過することにより、残留鉄イオン濃度を分析し、鉄イオンの析出抑制効果を調べた。この残留鉄イオン濃度が多い方が、析出抑制効果が高いことを示す。
2) Test method After adding the chemicals shown in Table 1 to each of the simulated test waters A and B (however, no chemicals were added in Comparative Examples 1 and 4), the ferrous sulfate concentration of iron ion (Fe 2+ ) was 3 mg / It added so that it might become L, and stirred for 10 minutes. This solution was filtered through a 0.1 μm microfilter to analyze the residual iron ion concentration and investigate the effect of suppressing the precipitation of iron ions. A higher residual iron ion concentration indicates a higher precipitation suppression effect.

3) 試験結果及び考察結果
試験結果を表1に示す。
3) Test results and discussion results Table 1 shows the test results.

Figure 2010274195
Figure 2010274195

表1より、次のことが分かる。
FeO試薬無添加の場合(比較例1〜3、参考例1)においても、1−ヒドロキシエチリデン−1,1−ジホスホン酸と他の薬剤では、1−ヒドロキシエチリデン−1,1−ジホスホン酸の方がやや析出抑制効果が優れるもののその効果に大差はない。これに対して、FeO試薬を添加した場合(比較例4〜6、実施例1)には、他の薬剤では殆どスケール析出防止効果が得られないが、1−ヒドロキシエチリデン−1,1−ジホスホン酸であれば十分な効果が得られ、本発明による1−ヒドロキシエチリデン−1,1−ジホスホン酸のスケール析出抑制効果が顕著である。
Table 1 shows the following.
Even in the case where no FeO reagent was added (Comparative Examples 1 to 3, Reference Example 1), 1-hydroxyethylidene-1,1-diphosphonic acid was used for 1-hydroxyethylidene-1,1-diphosphonic acid and other drugs. Although the precipitation suppressing effect is slightly superior, there is no great difference in the effect. On the other hand, when the FeO reagent is added (Comparative Examples 4 to 6, Example 1), the effect of preventing the precipitation of scale is hardly obtained with other chemicals, but 1-hydroxyethylidene-1,1-diphosphone is obtained. If it is an acid, a sufficient effect is obtained, and the effect of inhibiting the precipitation of scale of 1-hydroxyethylidene-1,1-diphosphonic acid according to the present invention is remarkable.

[実機試験]
1) 対象水系
転炉1次集塵機送りライン(図1において、2次集塵機3の集塵排水を1次集塵機2に循環するライン)
[Real machine test]
1) Target water system Converter primary dust collector feed line (in Fig. 1, the line that circulates the dust collection wastewater of the secondary dust collector 3 to the primary dust collector 2)

2) 試験方法
1次集塵機送りラインから分岐した各試験ラインにそれぞれ表3に示す薬剤を注入し(ただし比較例7,10では薬剤無添加)、ステンレス試験チューブ(径:1/2B、長さ:100mm)に流速2m/sで通水したときのスケール付着速度を調べた。
なお、試験はそれぞれ2回行い、1回目を比較例7〜9と実施例2、2回目を比較例10,11と実施例3とした。
2) Test method The chemicals shown in Table 3 were injected into each test line branched from the primary dust collector feed line (no chemical added in Comparative Examples 7 and 10), and a stainless steel test tube (diameter: 1 / 2B, length) : 100 mm), the scale deposition rate when water was passed at a flow rate of 2 m / s was examined.
Each test was performed twice, and the first time was set as Comparative Examples 7 to 9 and Example 2, and the second time was set as Comparative Examples 10 and 11 and Example 3.

各々の試験中の水質は次の通りであった。
1回目:懸濁物質=560〜720mg/L,Feイオン=52〜61mg/L,
pH=6.5〜7.0
2回目:懸濁物質=450〜1,230mg/L,Feイオン=20〜36mg/L,
pH=6.5〜7.0
The water quality during each test was as follows.
1st: Suspended substance = 560-720 mg / L, Fe ion = 52-61 mg / L,
pH = 6.5-7.0
Second time: suspended substance = 450-1,230 mg / L, Fe ion = 20-36 mg / L,
pH = 6.5-7.0

また、各回における無薬注時の試験チューブ内付着物を分析した結果は下記表2の通りであり、酸化鉄等を主成分とする鉄スケールが析出、付着していたことを確認した。   Moreover, the result of having analyzed the deposit | attachment in the test tube at the time of no chemical injection in each time is as Table 2 below, and it confirmed that the iron scale which has iron oxide etc. as a main component precipitated and adhered.

Figure 2010274195
Figure 2010274195

3) 試験結果及び考察
試験結果を表3に示す。
3) Test results and discussion The test results are shown in Table 3.

Figure 2010274195
Figure 2010274195

表3より、鉄系懸濁物質が100mg/L以上存在し、pH7以下で鉄イオン濃度が1mg/L以上の、鉄スケールが析出、付着する転炉集塵水系において、従来のスケール防止剤に比べて、本発明で用いる1−ヒドロキシエチリデン−1,1−ジホスホン酸が優れたスケール付着防止効果を発揮することが分かる。   According to Table 3, in the converter dust collection water system where iron-based suspended matter is present at 100 mg / L or more, the iron ion concentration is 1 mg / L or more at pH 7 or less, and the iron scale is deposited and adhered, In comparison, it can be seen that 1-hydroxyethylidene-1,1-diphosphonic acid used in the present invention exhibits an excellent anti-scale adhesion effect.

1 転炉
2 1次集塵機
3 2次集塵機
4 誘引通風ファン
5 回収弁
7 OGガスホルダ
10 煙突
20 水処理系統
DESCRIPTION OF SYMBOLS 1 Converter 2 Primary dust collector 3 Secondary dust collector 4 Induction fan 5 Recovery valve 7 OG gas holder 10 Chimney 20 Water treatment system

Claims (5)

鉄系懸濁物質が100mg/L以上存在し、pH7以下、鉄イオン濃度が1mg/L以上である転炉集塵水系に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加することを特徴とする転炉集塵水系の鉄スケール付着防止方法。   1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is added to the converter dust collection water system in which the iron-based suspended substance is present at 100 mg / L or more, the pH is 7 or less, and the iron ion concentration is 1 mg / L or more. A method for preventing iron scale adhesion in a converter dust-collecting water system, characterized by comprising: 請求項1において、前記鉄系懸濁物質が、FeO、Fe、Fe、Fe、及びFeO(OH)よりなる群から選ばれる1種又は2種以上を主成分とすることを特徴とする転炉集塵水系の鉄スケール付着防止方法。 2. The main component of claim 1, wherein the iron-based suspended substance is one or more selected from the group consisting of FeO, Fe 2 O 3 , Fe 3 O 4 , Fe, and FeO (OH). An iron scale adhesion prevention method for converter dust collection water system. 前記転炉集塵水系が、転炉排ガスを1次集塵機及び2次集塵機で順次集塵処理している集塵水系であって、
1次集塵機から排出される集塵排水を水処理した後、2次集塵機の集塵用水として給水し、2次集塵機から排出される集塵排水を1次集塵機の集塵用水として循環するシリーズ給水の集塵方式においては、2次集塵機から排出され1次集塵機に循環される循環水及び/又は1次集塵機から排出され水処理後に2次集塵機に給水される処理水に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加し、
1次集塵機から排出される集塵排水を水処理した後、1次集塵機の集塵用水として循環し、2次集塵機から排出される集塵排水を水処理した後、2次集塵機の集塵用水として循環するパラレル給水の集塵方式においては、1次集塵機から排出され水処理後に1次集塵機に循環される循環水及び/又は2次集塵機から排出され水処理後に2次集塵機に循環される循環水に、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を添加することを特徴とする転炉集塵水系の鉄スケール付着防止方法。
The converter dust collection water system is a dust collection water system for sequentially collecting dust from a converter exhaust gas by a primary dust collector and a secondary dust collector,
Series water supply that treats dust collection wastewater discharged from the primary dust collector as water for secondary dust collector, and circulates dust collection wastewater discharged from the secondary dust collector as dust collection water for the primary dust collector. In this type of dust collection system, 1-hydroxyethylidene is used as circulating water discharged from the secondary dust collector and circulated to the primary dust collector and / or treated water supplied from the primary dust collector to the secondary dust collector after water treatment. 1,1-diphosphonic acid and / or salt thereof is added,
Dust drainage discharged from the primary dust collector is treated with water, circulated as dust collection water for the primary dust collector, and the dust collection wastewater discharged from the secondary dust collector is treated with water, and then the dust collection water for the secondary dust collector is collected. In the parallel feed water dust collection system that circulates as: circulating water discharged from the primary dust collector and circulated to the primary dust collector after water treatment and / or circulation discharged from the secondary dust collector and circulated to the secondary dust collector after water treatment A method for preventing iron scale adhesion in a converter dust collection water system, which comprises adding 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof to water.
請求項1ないし3のいずれか1項において、1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を、転炉集塵水系における濃度が0.1〜100mg/Lとなるように添加することを特徴とする転炉集塵水系の鉄スケール付着防止方法。   The 1-hydroxyethylidene-1,1-diphosphonic acid and / or salt thereof is added so that the concentration in the converter dust collection water system is 0.1 to 100 mg / L in any one of claims 1 to 3. An iron scale adhesion prevention method for a converter dust collection water system. 1−ヒドロキシエチリデン−1,1−ジホスホン酸及び/又はその塩を含むことを特徴とする転炉集塵水系の鉄スケール付着防止剤。   An iron scale adhesion preventive for a converter dust collection water system comprising 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof.
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