JP4843165B2 - Duct disposed on the outlet side of the converter - Google Patents

Duct disposed on the outlet side of the converter Download PDF

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Publication number
JP4843165B2
JP4843165B2 JP2001275922A JP2001275922A JP4843165B2 JP 4843165 B2 JP4843165 B2 JP 4843165B2 JP 2001275922 A JP2001275922 A JP 2001275922A JP 2001275922 A JP2001275922 A JP 2001275922A JP 4843165 B2 JP4843165 B2 JP 4843165B2
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Prior art keywords
converter
duct
reinforcing
heat
reinforcing rib
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JP2003083686A (en
Inventor
聡一郎 田中
博幸 田中
泰 有信
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Mitsui Mining and Smelting Co Ltd
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Mitsui Mining and Smelting Co Ltd
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【０００１】
【発明の属する技術分野】
本発明は、ガス中に含まれるＳＯ2 を触媒によってＳＯ3 に転換する転化器の出側に配設されて、ＳＯ3 含有ガスを転化器から熱交換器へ送給するダクトに関する。
【０００２】
【従来の技術】
一般に、硫化鉱を原料とする製錬炉（たとえば銅製錬で用いる自溶炉等）から発生するガスにはＳＯ2 が含まれている。このようなガス中に含有されるＳＯ2 は、触媒を用いてＳＯ3 に転換し、硫酸の製造原料として回収される。ガス中のＳＯ2 を回収するにあたって、転化器を用いてＳＯ2 をＳＯ3 として回収した後、 さらにＳＯ3 から硫酸を製造する技術が広く知られている。
【０００３】
転化器は触媒によってガス中のＳＯ2 をＳＯ3 として回収する装置であるが、ＳＯ2 からＳＯ3 に転化するにあたっては、転化器入口温度が 400〜450 ℃必要であり、触媒との反応熱により、さらに高温（約 600℃）となるため、熱交換器に送給して排熱を回収した後、硫酸酸製造工程に送給される。
図３は、ＳＯ3 含有ガスを転化器から熱交換器へ送給するために転化器の出側に配設される従来のダクトの例を模式的に示す斜視図である。
【０００４】
風道部１は、その中を流通する高温のガスによって昇温されて変形するのを防止することを目的として、風道部１内に複数個の補強支柱２が配設され、風道部１の外面に補強リブ３が配設される。補強支柱２や補強リブ３は、通常、溶接によって風道部１に固定される。これらの風道部１，補強支柱２および補強リブ３には高温強度および耐クリープ性が要求されるので、耐熱性のCr−Ni系鋼材が広く使用されている。
【０００５】
さらに風道部１の外面は保温材４で被覆される。風道部１の外面を保温材４で被覆した状態の補強リブ３近傍の部分断面図を図４に示す。
補強リブ３の高さｔ1 （すなわち風道部１外面から補強リブ３先端までの距離）と保温材４の厚さｔ2 （すなわち風道部１外面から保温材４表面までの距離）は、図４に示すように、ほぼｔ1 ＝ｔ2 である。したがって、補強リブ３先端は保温性が劣り、大気によって冷却される。
【０００６】
その結果、下記のような問題が生じる。
(1) 補強リブ３先端が局部的に冷却されるので、補強リブ３の溶接部に熱応力が発生して亀裂が生じる。
(2) 風道部１が変形するので、補強支柱２の溶接部に亀裂が生じる。
(3) 風道部１の振動によって補強支柱２の溶接部に亀裂が生じる。
【０００７】
そこで補強リブ３先端の保温性を向上することを目的として、保温材４の厚さｔ2 を増大することも考えられる。 しかし保温材４の厚さｔ2 を増大すると、ダクト全体の質量が増大するので、風道部１は高温のガスによって昇温されて変形しやすくなる。風道部１が変形すると、 補強支柱２や補強リブ３の溶接部に亀裂が生じて、ガス漏れの原因になる。
【０００８】
【発明が解決しようとする課題】
本発明は上記のような問題を解決し、補強リブの局部的な冷却を防止し、変形や亀裂の発生を抑制できるダクトを提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明は、転化器の出側に配設されてその転化器から排出されるＳＯ 3 ガスが流通するダクトであって、Cr、NiおよびMoを含有する耐熱性ステンレス鋼からなる風道部と、風道部内に配設されかつ耐熱性ステンレス鋼からなる補強支柱と、風道部の外面に配設されて風道部の外面からの高さｔ 1 が50〜250mm の範囲内を満足しかつ耐熱性ステンレス鋼からなる補強リブと、風道部の外面を被覆しかつ風道部の外面からの厚さｔ 2 が 150〜300mm の範囲内を満足する保温材とを有し、かつ補強リブの高さｔ 1 と保温材の厚さｔ 2 がｔ 2 ≧ｔ 1 ＋50mmを満足するダクトである。
【００１１】
【発明の実施の形態】
図１は、ＳＯ3 含有ガスを転化器から熱交換器へ送給するために転化器の出側に配設される本発明のダクトの例を模式的に示す斜視図である。
風道部１は、その中を流通する高温のガスによって昇温されて変形するのを防止することを目的として、風道部１内に複数個の補強支柱２が配設され、風道部１の外面に補強リブ３が配設される。さらに風道部１の外面は保温材４で被覆される。風道部１の外面を保温材４で被覆した状態の補強リブ３近傍の部分断面図を図２に示す。
【００１２】
本発明のダクトを構成する風道部１，補強支柱２および補強リブ３には、優れた高温強度および耐クリープ性を有するCr，Ni，Moを含有する耐熱性ステンレス鋼を使用する。Cr−Ni−Mo系耐熱性ステンレス鋼を使用することによって、従来のダクトに比べて補強リブ３の高さｔ1 を減少できる。すなわち補強リブ３の高さｔ1 が50mm未満では、風道部１を補強する効果が得られない。 一方、 250mm を超えると、 後述する保温材４の保温効果が補強リブ３の先端で十分に得られない。したがって本発明では、補強リブ３の高さｔ1 は50〜250mm の範囲内を満足する必要がある。 なお、好ましくは 100〜150mm である。
【００１３】
補強リブ３の高さｔ1 を減少すると、補強リブ３が軽量化される。したがって従来のダクトに比べて保温材４の厚さｔ2 を増加して、保温性を向上できる。すなわち保温材４の厚さｔ2 が 150mm未満では、ダクトおよび補強リブ３先端で十分な保温効果が得られない。 一方、 300mmを超えると、 ダクト全体の質量が増大するので、風道部１が変形しやすくなる。したがって本発明では、保温材４の厚さｔ2 は 150〜300mm の範囲内を満足する必要がある。 なお、好ましくは 200〜300mm である。ただし補強リブ３の先端の保温性を確保するため、ｔ2 ≧ｔ1 ＋50mmを満足するものとする。
【００１４】
また、補強支柱２にも優れた高温強度および耐クリープ性を有するCr，Ni，Moを含有する耐熱性ステンレス鋼を使用するので、補強支柱２の本数を削減できる。ダクトの軽量化にあたっては、補強支柱２の本数を削減する方が、 補強支柱２の断面積を減少するより好ましい。 その結果、 亀裂発生の起点となる溶接部を削減できる。
【００１５】
本発明においては、保温材４は特定の材質に限定しない。たとえば、 ガラス繊維やパーライト等の従来から知られている保温材を使用できる。
このようにして補強リブ３の高さｔ1 を減少し、保温材４の厚さｔ2 を増加することによって、補強リブ３先端の上側にも十分な量の保温材４を被覆できる。したがって補強リブ３先端の極部的な冷却を防止し、変形や亀裂の発生を抑制できる。その結果、 補強支柱２の数を削減することができ、ダクトの一層の軽量化に効果を発揮するばかりでなく、風道部１内の通気性も改善される。
【００１６】
【実施例】
図１に示すダクトを転化器（図示せず）の出側に配設して、ＳＯ3 を含有する約 600℃のガスを転化器から高温熱交換器（図示せず）へ送給した。風道部１，補強支柱２および補強リブ３には、Cr：18質量％，Ni：12質量％，Mo： 2.5質量％を含有する耐熱性ステンレス鋼（ＪＩＳ規格 SUS316 相当）を使用し、補強リブ３の高さｔ1 は100mm とした。保温材４はパーライトを使用し、保温材４の厚さｔ2 は200mm とした。なお、補強支柱２は４本とした。これを発明例とする。
【００１７】
一方、比較例として、図３に示すダクトを転化器（図示せず）の出側に配設して、ＳＯ3 含有ガスを転化器から高温熱交換器（図示せず）へ送給した。風道部１，補強支柱２および補強リブ３には、Cr：18質量％，Ni：８質量％を含有するステンレス鋼（ＪＩＳ規格 SUS304 相当）を使用し、補強リブ３の高さｔ1 は150mm とした。保温材４はパーライトを使用し、保温材４の厚さｔ2 は150mm とした。なお、補強支柱２は４本とした。
【００１８】
発明例と比較例について、転化器を稼動させながらダクトから生じるガス漏れの有無を調査した。その結果、 発明例では、 転化器を 1.5年以上稼動してもダクトからガス漏れは生じなかった。 しかし比較例では、 転化器を 0.5年稼動するとダクトからガス漏れが生じた。このガス漏れは、補強リブ３や補強支柱２の溶接部に生じた亀裂からガスが漏れたものである。
【００１９】
このようにして本発明では、補強リブ３先端の局部的な冷却を防止して、変形や亀裂の発生を抑制できることが確かめられた。
【００２０】
【発明の効果】
本発明では、転化器から熱交換器にガスを送給するダクトの変形や亀裂を抑制できる。
【図面の簡単な説明】
【図１】本発明のダクトの例を模式的に示す斜視図である。
【図２】本発明のダクトの補強リブ近傍を模式的に示す部分断面図である。
【図３】従来のダクトの例を模式的に示す斜視図である。
【図４】従来のダクトの補強リブ近傍を模式的に示す部分断面図である。
【符号の説明】
１ 風道部
２ 補強支柱
３ 補強リブ
４ 保温材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a duct that is disposed on the outlet side of a converter that converts SO 2 contained in a gas into SO 3 by a catalyst and feeds the SO 3 -containing gas from the converter to a heat exchanger.
[0002]
[Prior art]
In general, SO 2 is contained in a gas generated from a smelting furnace using sulfide ore as a raw material (for example, a flash smelting furnace used in copper smelting). SO 2 contained in such a gas is converted into SO 3 using a catalyst and recovered as a raw material for producing sulfuric acid. In recovering SO 2 in a gas, a technique for producing sulfuric acid from SO 3 after recovering SO 2 as SO 3 using a converter is widely known.
[0003]
The converter is a device that recovers SO 2 in the gas as SO 3 using a catalyst. In order to convert SO 2 to SO 3 , the converter inlet temperature is required to be 400-450 ° C, and the reaction heat with the catalyst. As a result, the temperature becomes higher (about 600 ° C.), so that it is sent to a heat exchanger to recover waste heat and then sent to the sulfuric acid production process.
FIG. 3 is a perspective view schematically showing an example of a conventional duct arranged on the outlet side of the converter for supplying the SO 3 -containing gas from the converter to the heat exchanger.
[0004]
The airway portion 1 is provided with a plurality of reinforcing struts 2 in the airway portion 1 for the purpose of preventing the airway portion 1 from being heated and deformed by high-temperature gas flowing therethrough. Reinforcing ribs 3 are disposed on the outer surface of 1. The reinforcing column 2 and the reinforcing rib 3 are usually fixed to the airway portion 1 by welding. Since these wind passage parts 1, the reinforcing struts 2 and the reinforcing ribs 3 are required to have high-temperature strength and creep resistance, heat-resistant Cr-Ni steel materials are widely used.
[0005]
Further, the outer surface of the air passage portion 1 is covered with a heat insulating material 4. FIG. 4 shows a partial cross-sectional view of the vicinity of the reinforcing rib 3 in a state where the outer surface of the air passage portion 1 is covered with the heat insulating material 4.
The height t 1 of the reinforcing rib 3 (that is, the distance from the outer surface of the air passage portion 1 to the tip of the reinforcing rib 3) and the thickness t 2 of the heat insulating material 4 (that is, the distance from the outer surface of the air passage portion 1 to the surface of the heat insulating material 4) As shown in FIG. 4, t 1 = t 2 . Therefore, the end of the reinforcing rib 3 is inferior in heat retention and is cooled by the atmosphere.
[0006]
As a result, the following problems occur.
(1) Since the tips of the reinforcing ribs 3 are locally cooled, thermal stress is generated at the welded portions of the reinforcing ribs 3 and cracks are generated.
(2) Since the airway portion 1 is deformed, a crack is generated in the welded portion of the reinforcing column 2.
(3) Cracks occur in the welded portion of the reinforcing support 2 due to the vibration of the airway portion 1.
[0007]
Therefore, it is conceivable to increase the thickness t 2 of the heat insulating material 4 for the purpose of improving the heat retaining property at the tip of the reinforcing rib 3. However, when the thickness t 2 of the heat insulating material 4 is increased, the mass of the entire duct increases, so that the air passage portion 1 is easily heated and deformed by the high-temperature gas. When the air passage portion 1 is deformed, a crack is generated in the welded portion of the reinforcing support 2 and the reinforcing rib 3, which causes gas leakage.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to solve the above problems, and to provide a duct that can prevent local cooling of a reinforcing rib and suppress the occurrence of deformation and cracks.
[0009]
[Means for Solving the Problems]
The present invention is a duct that is disposed on the outlet side of a converter and through which SO 3 gas discharged from the converter circulates, and an air passage portion made of heat-resistant stainless steel containing Cr, Ni, and Mo; A reinforcing support made of heat-resistant stainless steel disposed in the air passage and a height t 1 from the outer surface of the air passage that satisfies the range of 50 to 250 mm. and it possesses a reinforcing rib made of a heat resistant stainless steel, and a heat insulating material having a thickness t 2 of the outer surface of the wind path unit from the outer surface of the covering vital wind path unit satisfies a range of 150 to 300 mm, and reinforcing The duct is such that the height t 1 of the rib and the thickness t 2 of the heat insulating material satisfy t 2 ≧ t 1 +50 mm .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view schematically showing an example of a duct of the present invention disposed on the outlet side of a converter for supplying SO 3 -containing gas from the converter to a heat exchanger.
The airway portion 1 is provided with a plurality of reinforcing struts 2 in the airway portion 1 for the purpose of preventing the airway portion 1 from being heated and deformed by high-temperature gas flowing therethrough. Reinforcing ribs 3 are disposed on the outer surface of 1. Further, the outer surface of the air passage portion 1 is covered with a heat insulating material 4. FIG. 2 shows a partial cross-sectional view of the vicinity of the reinforcing rib 3 in a state where the outer surface of the air passage portion 1 is covered with the heat insulating material 4.
[0012]
For the airway part 1, the reinforcing support 2 and the reinforcing rib 3 constituting the duct of the present invention, heat resistant stainless steel containing Cr, Ni, Mo having excellent high temperature strength and creep resistance is used. By using Cr—Ni—Mo heat resistant stainless steel, the height t 1 of the reinforcing rib 3 can be reduced as compared with the conventional duct. That is, if the height t 1 of the reinforcing rib 3 is less than 50 mm, the effect of reinforcing the air passage portion 1 cannot be obtained. On the other hand, if it exceeds 250 mm, the heat retaining effect of the heat retaining material 4 described later cannot be sufficiently obtained at the end of the reinforcing rib 3. Therefore, in the present invention, the height t 1 of the reinforcing rib 3 needs to satisfy the range of 50 to 250 mm. The thickness is preferably 100 to 150 mm.
[0013]
When the height t 1 of the reinforcing rib 3 is decreased, the weight of the reinforcing rib 3 is reduced. Therefore, the thickness t 2 of the heat insulating material 4 can be increased as compared with the conventional duct, and the heat insulating property can be improved. That is, if the thickness t 2 of the heat insulating material 4 is less than 150 mm, a sufficient heat insulating effect cannot be obtained at the duct and the end of the reinforcing rib 3. On the other hand, if it exceeds 300 mm, the mass of the entire duct increases, so that the airway portion 1 is easily deformed. Therefore, in the present invention, the thickness t 2 of the heat insulating material 4 needs to satisfy the range of 150 to 300 mm. In addition, Preferably it is 200-300 mm. However, it is assumed that t 2 ≧ t 1 +50 mm is satisfied in order to ensure the heat retaining property at the tip of the reinforcing rib 3.
[0014]
Further, since the heat-resistant stainless steel containing Cr, Ni, and Mo having excellent high-temperature strength and creep resistance is used for the reinforcing column 2, the number of the reinforcing columns 2 can be reduced. In reducing the weight of the duct, it is more preferable to reduce the number of reinforcing columns 2 than to reduce the cross-sectional area of the reinforcing columns 2. As a result, it is possible to reduce the number of welds from which cracks start.
[0015]
In the present invention, the heat insulating material 4 is not limited to a specific material. For example, conventionally known heat insulating materials such as glass fiber and pearlite can be used.
In this way, by reducing the height t 1 of the reinforcing rib 3 and increasing the thickness t 2 of the heat insulating material 4, a sufficient amount of the heat insulating material 4 can be covered also on the upper end of the reinforcing rib 3. Therefore, extreme cooling at the tip of the reinforcing rib 3 can be prevented, and deformation and cracking can be suppressed. As a result, the number of reinforcing posts 2 can be reduced, and not only the effect of further reducing the weight of the duct is exhibited, but also the air permeability in the air passage portion 1 is improved.
[0016]
【Example】
The duct shown in FIG. 1 was disposed on the outlet side of a converter (not shown ), and a gas of about 600 ° C. containing SO 3 was fed from the converter to a high-temperature heat exchanger (not shown). For the airway part 1, the reinforcement strut 2 and the reinforcement rib 3, heat resistant stainless steel (equivalent to JIS standard SUS316) containing Cr: 18% by mass, Ni: 12% by mass, Mo: 2.5% by mass is used for reinforcement. The height t 1 of the rib 3 was 100 mm. The heat insulating material 4 used perlite, and the thickness t 2 of the heat insulating material 4 was 200 mm. In addition, the reinforcement support | pillar 2 was made into four pieces. This is an invention example.
[0017]
On the other hand, as a comparative example, the duct shown in FIG. 3 was disposed on the outlet side of the converter (not shown ), and the SO 3 -containing gas was fed from the converter to the high-temperature heat exchanger (not shown). Stainless steel (corresponding to JIS standard SUS304) containing Cr: 18% by mass and Ni: 8% by mass is used for the airway portion 1, the reinforcing support 2 and the reinforcing rib 3, and the height t 1 of the reinforcing rib 3 is 150 mm. The heat insulating material 4 used perlite, and the thickness t 2 of the heat insulating material 4 was 150 mm. In addition, the reinforcement support | pillar 2 was made into four pieces.
[0018]
About the invention example and the comparative example, the presence or absence of the gas leak which arises from a duct was investigated, operating a converter. As a result, in the inventive example, no gas leaked from the duct even when the converter was operated for more than 1.5 years. However, in the comparative example, the gas leaked from the duct when the converter was operated for 0.5 years. This gas leak is a gas leak from a crack generated in the welded portion of the reinforcing rib 3 or the reinforcing column 2.
[0019]
Thus, in the present invention, it was confirmed that the local cooling of the tip of the reinforcing rib 3 can be prevented and the occurrence of deformation and cracks can be suppressed.
[0020]
【The invention's effect】
In this invention, the deformation | transformation and crack of a duct which supply gas to a heat exchanger from a converter can be suppressed.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing an example of a duct of the present invention.
FIG. 2 is a partial cross-sectional view schematically showing the vicinity of a reinforcing rib of a duct according to the present invention.
FIG. 3 is a perspective view schematically showing an example of a conventional duct.
FIG. 4 is a partial sectional view schematically showing the vicinity of a reinforcing rib of a conventional duct.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Airway part 2 Reinforcement prop 3 Reinforcement rib 4 Insulation

Claims (1)

転化器の出側に配設されて該転化器から排出されるＳＯ 3 ガスが流通するダクトであって、Cr、NiおよびMoを含有する耐熱性ステンレス鋼からなる風道部と、前記風道部内に配設されかつ前記耐熱性ステンレス鋼からなる補強支柱と、前記風道部の外面に配設されて前記風道部の外面からの高さｔ 1 が50〜250mm の範囲内を満足しかつ前記耐熱性ステンレス鋼からなる補強リブと、前記風道部の外面を被覆しかつ前記風道部の外面からの厚さｔ 2 が 150〜300mm の範囲内を満足する保温材とを有し、かつ前記補強リブの高さｔ 1 と前記保温材の厚さｔ 2 がｔ 2 ≧ｔ 1 ＋50mmを満足することを特徴とするダクト。 A duct that is disposed on the outlet side of the converter and through which SO 3 gas discharged from the converter circulates, an air passage portion made of heat-resistant stainless steel containing Cr, Ni, and Mo, and the air passage A reinforcing column made of the heat-resistant stainless steel, and a height t 1 from the outer surface of the air passage portion that satisfies the range of 50 to 250 mm. and it possesses a reinforcing rib formed of the heat resistant stainless steel, and a heat insulating material covering the outer surface of the wind path unit and the thickness t 2 from the outer surface of the air path unit satisfies a range of 150~300mm The duct is characterized in that a height t 1 of the reinforcing rib and a thickness t 2 of the heat insulating material satisfy t 2 ≧ t 1 +50 mm .
JP2001275922A 2001-09-12 2001-09-12 Duct disposed on the outlet side of the converter Expired - Lifetime JP4843165B2 (en)

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JP4843165B2 true JP4843165B2 (en) 2011-12-21

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Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS597820A (en) * 1982-07-06 1984-01-17 Babcock Hitachi Kk Reinforcement for duct
JPS62141030A (en) * 1985-12-16 1987-06-24 Showa Denko Kk Purification of ladder-like silicone oligomer
JPH08194304A (en) * 1995-01-19 1996-07-30 Hitachi Cable Ltd Baking device
JP3774555B2 (en) * 1997-11-06 2006-05-17 三菱レイヨン株式会社 Smoke exhaust duct and manufacturing method thereof
JPH11189404A (en) * 1997-12-26 1999-07-13 Mitsui Mining & Smelting Co Ltd Operation of converter in contact type sulfuric acid plant
JP2001165483A (en) * 1999-12-08 2001-06-22 Ishikawajima Harima Heavy Ind Co Ltd Exhaust equipment

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