JP5707677B2 - Iron scale adhesion prevention method and adhesion preventive agent for converter dust collection water system - Google Patents
Iron scale adhesion prevention method and adhesion preventive agent for converter dust collection water system Download PDFInfo
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- 239000000428 dust Substances 0.000 title claims description 206
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 166
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 136
- 229910052742 iron Inorganic materials 0.000 title claims description 87
- 238000000034 method Methods 0.000 title claims description 24
- 230000002265 prevention Effects 0.000 title claims description 8
- 239000003795 chemical substances by application Substances 0.000 title claims description 6
- 230000003449 preventive effect Effects 0.000 title claims description 5
- 150000003839 salts Chemical class 0.000 claims description 35
- DBVJJBKOTRCVKF-UHFFFAOYSA-N Etidronic acid Chemical compound OP(=O)(O)C(O)(C)P(O)(O)=O DBVJJBKOTRCVKF-UHFFFAOYSA-N 0.000 claims description 34
- 239000000126 substance Substances 0.000 claims description 23
- 239000002351 wastewater Substances 0.000 claims description 20
- 230000003405 preventing effect Effects 0.000 claims description 13
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 23
- -1 iron ions Chemical class 0.000 description 23
- 238000001556 precipitation Methods 0.000 description 20
- 230000000694 effects Effects 0.000 description 13
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 7
- 239000007787 solid Substances 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 5
- 235000013980 iron oxide Nutrition 0.000 description 5
- 238000001179 sorption measurement Methods 0.000 description 5
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 4
- 230000002378 acidificating effect Effects 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- 239000011362 coarse particle Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 239000002455 scale inhibitor Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 229940079593 drug Drugs 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 230000000181 anti-adherent effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- OMAAXMJMHFXYFY-UHFFFAOYSA-L calcium trioxidophosphanium Chemical compound [Ca+2].[O-]P([O-])=O OMAAXMJMHFXYFY-UHFFFAOYSA-L 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000009991 scouring Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
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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 matter is 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
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
（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
The dust collection waste water of the
In addition, although the dust collection waste_water | drain from each
（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 wastewater discharged from the primary dust collector 2 is treated with water and circulated as dust collection water for the primary dust collector 2, and the dust collection wastewater discharged from the
In this case, the dust collection wastewater of the primary dust collector 2 and the dust collection wastewater of the
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 precipitation 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 an iron-based scale adheres due to precipitation of iron ions in the presence of an iron-based suspended substance. 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.
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、転炉集塵水系のうち、集塵機に対して集塵用水として給水される水であり、かつ鉄系懸濁物質が１００ｍｇ／Ｌ以上存在し、ｐＨ７以下、鉄イオン濃度が１ｍｇ／Ｌ以上である箇所に、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 method of preventing iron scale adhesion in the converter dust collection water system of the present invention (Claim 1) is water supplied as dust collection water to the dust collector in the converter dust collection water system , and the iron-based suspended matter. Is present at a pH of 7 or less and an iron ion concentration of 1 mg / L or more, 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is added.
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、Ｆｅ２Ｏ３、Ｆｅ３Ｏ４、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、請求項１又は２において、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。 According to a third aspect of the present invention, there is provided a method for preventing adhesion of iron scale to a converter dust collecting water system according to claim 1 or 2, wherein the converter dust collecting water system sequentially collects dust from a converter exhaust gas by a primary dust collector and a secondary dust collector. In this dust collection water system, the dust collection waste water discharged from the primary dust collector is treated with water, then supplied as dust collection water for the secondary dust collector, and the dust collection waste water discharged from the secondary dust collector is supplied to the primary dust collector. In the dust collection method of the series water supply that circulates as dust collection water, the circulating water discharged from the secondary dust collector and circulated to the primary dust collector and / or the treatment discharged from the primary dust collector and supplied to the secondary dust collector after water treatment 1-hydroxyethylidene-1,1-diphosphonic acid and / or salt thereof is added to water, and the dust collection waste water discharged from the primary dust collector is treated with water, and then circulated as dust collection water for the primary dust collector. Dust collection drainage discharged from the secondary dust collector In the dust collection method of parallel feed water that circulates as dust collection water for the secondary dust collector after treatment, it is discharged from the primary dust collector and circulated water and / or secondary dust collector that is circulated to the primary dust collector after water treatment. 1-hydroxyethylidene-1,1-diphosphonic acid and / or a salt thereof is added to circulating water circulated to the secondary dust collector after water treatment.
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
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、転炉集塵水系のうち、集塵機に対して集塵用水として給水される水であり、かつ鉄系懸濁物質が１００ｍｇ／Ｌ以上存在し、ｐＨ７以下、鉄イオン濃度が１ｍｇ／Ｌ以上である箇所に添加される鉄スケール付着防止剤であって、１−ヒドロキシエチリデン−１，１−ジホスホン酸及び／又はその塩を含むことを特徴とする。 The converter dust collection water system iron scale adhesion preventive agent of the present invention (Claim 5) is water supplied as dust collection water to the dust collector in the converter dust collection water system , and the iron suspended material. Is an iron scale anti-adhesive agent added to a location where 100 mg / L or more is present, pH is 7 or less, and the iron ion concentration is 1 mg / L or more, comprising 1-hydroxyethylidene-1,1-diphosphonic acid and / or its It contains a salt.
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.
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、Ｆｅ２Ｏ３、Ｆｅ３Ｏ４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 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 pH increase 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 the circulating water discharged from the secondary dust collector and circulated to the primary dust collector and / or treated water supplied to the secondary dust collector after being treated by the water discharged from the primary dust collector. .
For example, in FIG. 1, the dust collection wastewater of the
（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 feed water 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 line. 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
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 with two dust collectors, a primary dust collector and a secondary dust collector, and is a case where dust collection processing is performed with 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 without addition of FeO reagent and pH of only 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.
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 drugs, but 1-hydroxyethylidene-1,1-diphosphone is not 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
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.
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.
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
Claims (5)
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 collecting water system according to claim 1 or 2, wherein the converter dust collecting water system sequentially collects the converter exhaust gas with a primary dust collector and a secondary dust collector,
Series water supply in which the dust collection wastewater discharged from the primary dust collector is treated with water, then supplied as 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 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, then 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, followed by dust collection water for the secondary dust collector. 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.
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