JPH02197587A - Method for preventing corrosion of seawater cooling type heat exchanger made of stainless steel - Google Patents
Method for preventing corrosion of seawater cooling type heat exchanger made of stainless steelInfo
- Publication number
- JPH02197587A JPH02197587A JP1845189A JP1845189A JPH02197587A JP H02197587 A JPH02197587 A JP H02197587A JP 1845189 A JP1845189 A JP 1845189A JP 1845189 A JP1845189 A JP 1845189A JP H02197587 A JPH02197587 A JP H02197587A
- Authority
- JP
- Japan
- Prior art keywords
- seawater
- stainless steel
- ions
- corrosion
- rust
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013535 sea water Substances 0.000 title claims abstract description 45
- 238000005260 corrosion Methods 0.000 title claims abstract description 35
- 230000007797 corrosion Effects 0.000 title claims abstract description 34
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 33
- 239000010935 stainless steel Substances 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims description 18
- 238000001816 cooling Methods 0.000 title description 2
- 239000000498 cooling water Substances 0.000 claims abstract description 9
- -1 vanadate ion Chemical class 0.000 claims description 30
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 claims description 2
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 claims 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 abstract description 16
- 150000002500 ions Chemical class 0.000 abstract description 14
- 230000000694 effects Effects 0.000 abstract description 3
- VLAPMBHFAWRUQP-UHFFFAOYSA-L molybdic acid Chemical compound O[Mo](O)(=O)=O VLAPMBHFAWRUQP-UHFFFAOYSA-L 0.000 abstract 1
- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 abstract 1
- WQEVDHBJGNOKKO-UHFFFAOYSA-K vanadic acid Chemical compound O[V](O)(O)=O WQEVDHBJGNOKKO-UHFFFAOYSA-K 0.000 abstract 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 17
- 229910052742 iron Inorganic materials 0.000 description 12
- 241000269821 Scombridae Species 0.000 description 11
- 235000020640 mackerel Nutrition 0.000 description 11
- 229910000881 Cu alloy Inorganic materials 0.000 description 8
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- 239000012528 membrane Substances 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000003011 anion exchange membrane Substances 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000005536 corrosion prevention Methods 0.000 description 5
- 150000001768 cations Chemical class 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 150000001450 anions Chemical class 0.000 description 3
- 238000005341 cation exchange Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 235000003891 ferrous sulphate Nutrition 0.000 description 3
- 239000011790 ferrous sulphate Substances 0.000 description 3
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 3
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 159000000000 sodium salts Chemical class 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 229910001039 duplex stainless steel Inorganic materials 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 239000003014 ion exchange membrane Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Anti-Oxidant Or Stabilizer Compositions (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、ステンレス鋼製海水熱交換器の防食方法に関
する。詳しくは、海水を冷却水として使用する化学工業
用のステンレス鋼製熱交換器（クーラー、凝縮器）およ
び発電所復水器等の防食方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for preventing corrosion of a stainless steel seawater heat exchanger. Specifically, the present invention relates to a corrosion prevention method for stainless steel heat exchangers (coolers, condensers) for the chemical industry, power plant condensers, etc. that use seawater as cooling water.
（従来の技術）
海水熱交換器は、そのほとんどのものが管内に海水を流
し、管外（シェル側）にプロセス流体（気体、液体）あ
るいは水蒸気を導入して、プロセス流体等を海水との熱
交換により冷却あるいは凝縮する構造となっている。従
来、このような海水熱交換器の管材質としては銅合金が
主流であったが、銅合金はプロセス流体と接する管外面
側の耐食性が劣るため、最近ではステンレス鋼が使用さ
れるようになってきている。また、銅合金の耐海水性は
十分でないために、銅合金製熱交換器の場合には、防食
対策として海水中に鉄イオン（Ｐａ”つ＝亨を注入して
使用している。(Prior art) Most seawater heat exchangers allow seawater to flow inside the pipes, and process fluid (gas, liquid) or steam is introduced outside the pipes (on the shell side) to mix the process fluid, etc. with seawater. It has a structure that cools or condenses through heat exchange. Copper alloys have traditionally been the mainstream material for tubes in seawater heat exchangers, but since copper alloys have poor corrosion resistance on the outside of the tubes that come into contact with process fluids, stainless steel has recently been used. It's coming. Furthermore, since copper alloys do not have sufficient seawater resistance, copper alloy heat exchangers are used by injecting iron ions (Pa'') into seawater as a corrosion prevention measure.
海水熱交換器用のステンレス鋼としては、耐海水性に優
れたもの、例えば２相ステンレス鋼５ｕＳ３２９Ｊ２Ｌ
が使用されているが、プロセス流体が高温の場合、ある
いは管内面にもらい鯖が付着した場合、さらに海水の流
速が遅い場合には、局部腐食（孔食等）が発生すること
がある。特に問題になるのは、もらい鯖の影響である。Stainless steel for seawater heat exchangers is one with excellent seawater resistance, such as duplex stainless steel 5uS329J2L.
However, local corrosion (pitting corrosion, etc.) may occur if the process fluid is high temperature, if mackerel adheres to the inner surface of the tube, or if the flow rate of seawater is slow. A particular problem is the influence of mackerel.
ステンレス鋼は、周知のように、鉄錆あるいは鉄系酸化
物スラッジが表面に存在すると局部腐食感受性が増大す
る。As is well known, the presence of iron rust or iron-based oxide sludge on the surface of stainless steel increases the susceptibility to localized corrosion.
同一工場に、ステンレス鋼製熱交換器の他に銅合金製熱
交換器が多数共存する場合には、銅合金の防食を目的と
して海水中に鉄イオン注入を行うため、当然ステンレス
鋼製熱交換器にも鉄イオンの添加された海水が使用され
ることになり、この鉄イオンによるもらい請（鉄錆）の
ステンレス鋼製管内表面への付着は避けられない、この
ため、当初海水に対して十分な耐食性を有すると考えら
れていたステンレス鋼であっても、特に使用温度範囲ぎ
りぎりで使用する場合には、もらい錆の存在下で孔食が
発生してしまうことがある。If there are many copper alloy heat exchangers in addition to stainless steel heat exchangers in the same factory, iron ions are injected into the seawater to prevent corrosion of the copper alloy, so it is natural to use stainless steel heat exchangers. Seawater to which iron ions have been added will be used in the vessel, and it is unavoidable that these iron ions will cause iron rust to adhere to the inner surface of the stainless steel pipes. Even if stainless steel is considered to have sufficient corrosion resistance, pitting corrosion may occur in the presence of pitting rust, especially when used at the very edge of the operating temperature range.
この対策として、管端に近い部分の耐食性が問題となる
場合には、Ｚｎアノード等を使用するカソード防食を施
すことが有効である。しかし、Ｕ型熱交換器のＵ曲部に
孔食が発生しやすい場合には、カソード防食は適用困難
である。そのため、２相ステンレス鋼より耐食性が１ラ
ンク上の高Ｃｒ高Ｍ。As a countermeasure against this problem, if the corrosion resistance of the portion near the tube end is a problem, it is effective to apply cathodic corrosion protection using a Zn anode or the like. However, if pitting corrosion is likely to occur in the U-curved portion of the U-shaped heat exchanger, cathodic corrosion protection is difficult to apply. Therefore, the corrosion resistance of high Cr and high M is one rank higher than that of duplex stainless steel.
ステンレス鋼、いわゆるスーパーステンレス鋼（例えば
、２９Ｃｒ−４Ｍｏ−２ＮＩ鋼、２０Ｃｒ−１８Ｎｉ−
６Ｍｏ−０，２Ｎ鋼等）を使用することが効果的である
。しかし、材料コストが高いため、経済上の制約からこ
れらの材料を使用することはまれである。また、純チタ
ンの使用も有効であるが、同様の理由で使用されること
は少ない。このような現状から、当業者の間では、ステ
ンレス鋼製海水熱交換器の安価で有効な防食対策の開発
が望まれていた。Stainless steel, so-called super stainless steel (e.g. 29Cr-4Mo-2NI steel, 20Cr-18Ni-
6Mo-0,2N steel, etc.) is effective. However, due to the high material cost, these materials are rarely used due to economic constraints. Although pure titanium is also effective, it is rarely used for the same reason. Under these circumstances, there has been a desire among those skilled in the art to develop an inexpensive and effective anti-corrosion measure for stainless steel seawater heat exchangers.
（発明が解決しようとする課題）
本発明の目的は、海水を冷却水として使用するステンレ
ス鋼製熱交換器に＼おいて、管の内面に付着したちらい
錆（鉄錆）に由来する、管の耐海水性の劣化による局部
腐食発生を防止する方法を提供することであり、管材質
ではなく、環境側から問題を解決しようとするものであ
る。(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problem of rust caused by rust (iron rust) attached to the inner surface of the pipes in a stainless steel heat exchanger that uses seawater as cooling water. The purpose of this project is to provide a method for preventing local corrosion caused by deterioration of seawater resistance of pipes, and to solve the problem from the environment rather than the pipe material.
（課題を解決するための手段）
ステンレス鋼の耐孔食性は、もらい錆の存在下で劣化し
やすいことは古くから経験的に知られているが、その機
構については明らかでなかった。(Means for solving the problem) It has long been known empirically that the pitting corrosion resistance of stainless steel tends to deteriorate in the presence of pit rust, but the mechanism thereof has not been clear.
しかし、最近になって種々の酸化物のイオン交換膜的性
質が研究された結果、含水酸化鉄膜はアニオン交換膜的
性質を有することが判明した。However, as a result of recent research into the properties of various oxides as ion exchange membranes, it has been found that hydrated iron oxide membranes have properties similar to anion exchange membranes.
本発明者等は、もらい錆は含水酸化鉄に近い化学組成の
ものであると考えられるため、一種のアニオン交換膜的
性質を有するものと推定し、次のような着想を得た。ア
ニオン交換膜は、海水中のＣｌ２−のようなアニオンは
通過させるが、ステンレス鋼表面に存在しうるＰａ”、
Ｃｒ３＋、Ｍｌ”のようなカチオンは通過させない、そ
のため、アニオン交換膜でステンレス鋼表面が被われた
場合、膜下のステンレス鋼表面では、ＣＱ−、Ｆｅ”″
、Ｃｒ ′＋、Ｎｉ”等のイオンの濃縮が加速されてｐ
Ｈが低下し、不動態被膜が不安定となり、局部腐食感受
性が増大する。したがって、もらい錆の性質をアニオン
交換膜的なものからカチオン交換膜的なものに変化させ
ることが防食対策上有効である。The inventors of the present invention presumed that rust has a chemical composition similar to that of hydrated iron oxide, and thus has a type of anion exchange membrane property, and came up with the following idea. Anion exchange membranes allow anions such as Cl2- in seawater to pass through, but they do not allow anions such as Cl2- in seawater to pass through, but
Cations such as Cr3+ and Ml" are not allowed to pass through. Therefore, when the stainless steel surface is covered with an anion exchange membrane, CQ-, Fe""
The concentration of ions such as , Cr′+, Ni” is accelerated and p
H decreases, the passive film becomes unstable, and local corrosion susceptibility increases. Therefore, it is effective as a corrosion prevention measure to change the nature of the rust from that of an anion exchange membrane to that of a cation exchange membrane.
本発明者等は、上記着想に基づいて研究を重ねた結果、
もらい錆にモリブデン酸イオン、タングステン酸イオン
、あるいはバナジン酸イオンのような金属酸素酸イオン
を吸着させると、もらい錆がカチオン交換膜的な性質を
有するようになり、それによってステンレス鋼表面の局
部腐食感受性が低下して耐孔食性が著しく改善されるこ
とを見出し、本発明に到った。As a result of repeated research based on the above idea, the present inventors found that
When metal oxygen acid ions such as molybdate ions, tungstate ions, or vanadate ions are adsorbed onto the rust, the rust becomes cation-exchange membrane-like, thereby causing local corrosion on the stainless steel surface. It was discovered that sensitivity was reduced and pitting corrosion resistance was significantly improved, leading to the present invention.
本発明の要旨は、冷却水用海水中に、１９３１１以上の
濃度となるようにモリブデン酸イオン（Ｍｏｂ。The gist of the present invention is to prepare molybdate ions (Mob) in seawater for cooling water at a concentration of 19311 or higher.
ト）、タングステン酸イオン（ｉ４”−） 、およびバ
ナジン酸イオン（ＶＯｓ−）から選ばれた１種あるいは
２種以上を添加することを特徴とする、ステンレス鋼製
海水熱交換器の防食方法である。A method for preventing corrosion of a stainless steel seawater heat exchanger, characterized by adding one or more selected from g), tungstate ion (i4”-), and vanadate ion (VOs-). be.
（作用）
本発明の方法は、海水を冷却水としたステンレス鋼製熱
交換器の管内面の防食方法である。特に、同一工場にス
テンレス鋼製熱交換器の他に銅合金製熱交換器が共存す
る場合には、前記のように、銅合金の防食を目的とした
海水中への鉄イオンの注入が行われ、ステンレス鋼製管
内面へのもらい鯖付着が起きるために、本発明の方法を
適用することが有利である。(Function) The method of the present invention is a method for preventing corrosion of the inner surface of a tube of a stainless steel heat exchanger using seawater as cooling water. In particular, if there are copper alloy heat exchangers in addition to stainless steel heat exchangers in the same factory, iron ions are injected into seawater to prevent corrosion of the copper alloy, as described above. However, it is advantageous to apply the method of the present invention because mackerel deposits occur on the inner surface of stainless steel pipes.
上述のように、もらい錆の化学組成は、ＦＢ！０３・ｎ
Ｈｌｏで表される含水酸化鉄に近いものであり、中でも
γ−Ｆｅ００Ｈが最もよく見られる。上述のように含水
酸化鉄膜はカチオンの透過を抑制するのでアニオン交換
膜的に働くことが明らかとなっている。そのため、同じ
ような組成を持つもらい鯖が付着すると、ステンレス鋼
表面には海水中のｃＱ−アニオンは膜を通過して侵入す
るが、ステンレス鋼の近傍に存在するｐ ｅ ｔ ＋、
（、％＋、Ｎｉ１といったカチオンは膜を通過して拡散
できなくなり、もらい鯖の下側では金属塩化合物が濃縮
してｐＨが低下する結果、ステンレス鋼の不動態被膜が
不安定となり、ステンレス鋼の局部腐食感受性が増大す
ると考えられる。As mentioned above, the chemical composition of rust is FB! 03・n
It is similar to hydrated iron oxide represented by Hlo, and among them, γ-Fe00H is the most commonly seen. As mentioned above, it has become clear that the hydrated iron oxide membrane acts like an anion exchange membrane because it suppresses the permeation of cations. Therefore, when mackerel with a similar composition adheres to the stainless steel surface, cQ- anions in the seawater pass through the membrane and invade the stainless steel surface, but p et +, which exists near the stainless steel,
(,%+,Ni1, and other cations can no longer diffuse through the membrane, and as a result, the metal salt compounds are concentrated on the underside of the mackerel and the pH is lowered. As a result, the passive film on the stainless steel becomes unstable, and the stainless steel It is thought that the susceptibility to localized corrosion of
しかし、本発明の方法に従い、冷却水用の海水中に１ｐ
ｐ−以上の濃度となるようにモリブデン酸イオン（Ｍｏ
ｂ、”）、タングステン酸イオン（ｔｒｏｔ”−）、バ
ナジン酸イオン（ＶＯｓ−）のような酸素酸イオンを注
入すると、もらい鯖下でのステンレス鋼の耐孔食性が著
しく改善されることを１認した。その理由は断定できな
いが、これらの酸素酸イオンがもらい鯖表面に吸着され
、膜内のアニオンの透過を抑制するため、もらい端表面
がカチオン交換膜的性質を有するようになる。そのため
、もらい鯖に被われたステンレス鋼表面にはＣ２−の侵
入がなく、Ｆ１３”、Ｃｒ”、Ｎｉ”等のカチオンは海
水中に拡散することができるようになるため、不動態被
膜は安定化して局部腐食感受性が低下し、孔食の発ン酸
イオン、およびバナジン酸イオンの１種あるいは２種以
上を添加しても、その合計濃度が１１１９１１未満では
これらの酸素酸イオンはもらい鯖中に十分には吸着され
ず、もらい請下でのステンレス鋼の耐孔食性は十分には
改善されない。したがって、これらの酸素酸イオンの合
計濃度の下限はｉ ｐｐｍである。一方、合計濃度がｔ
ｏｏｏｐｐ−を超えるまでこれらの酸素酸イオンを海水
中に添加しても、もらい請下でのステンレス鋼の耐孔食
性の効果は飽和してしまい、その経済的メリットが薄れ
てしまうため、好ましくは１１０００ｐｐ以下の濃度に
なるようにこれらの酸素酸イオンを海水中に添加する。However, according to the method of the present invention, 1p in seawater for cooling water.
Molybdate ions (Mo
It has been shown that the pitting corrosion resistance of stainless steel under mackerel is significantly improved by implanting oxygen acid ions such as tungstate ions (trot”-) and vanadate ions (VOs-). Approved. Although the reason for this cannot be determined, these oxygen acid ions are adsorbed on the surface of the mackerel and suppress the permeation of anions within the membrane, so that the surface of the mackerel end has properties similar to a cation exchange membrane. Therefore, C2- does not invade the stainless steel surface covered with mackerel, and cations such as F13", Cr", and Ni" can diffuse into the seawater, resulting in a stable passive film. Even if one or more of pitting-producing acid ions and vanadate ions are added, if the total concentration is less than 111911, these oxygen acid ions will deteriorate in mackerel. Therefore, the lower limit of the total concentration of these oxygen acid ions is i ppm.On the other hand, if the total concentration is t
Even if these oxyacid ions are added to seawater until it exceeds ooopp-, the pitting corrosion resistance effect of stainless steel under contract will be saturated and its economic benefits will be diminished, so it is preferable to These oxygen acid ions are added to seawater to a concentration of 11,000 pp or less.
特に好ましい濃度範囲は、３〜５０ρｐ−である。A particularly preferred concentration range is 3 to 50 ρp-.
これらの酸素酸イオンの添加は、海水中で各酸素酸イオ
ンを生じる化合物、例えば各金属の含水酸化物、および
これらの酸素酸のナトリウム塩、アンモニウム塩等の結
晶または粉末をそのまま冷却用海水中に溶解させること
により、もしくは、これらの化合物の水溶液を同海水中
に注入することにより行うことができる。The addition of these oxyacid ions involves adding compounds that generate oxyacid ions in seawater, such as hydrous oxides of various metals, and crystals or powders of sodium salts and ammonium salts of these oxyacids, directly into the seawater for cooling. This can be done by dissolving these compounds in seawater or by injecting an aqueous solution of these compounds into the same seawater.
以下、実施例により本発明を説明する。The present invention will be explained below with reference to Examples.
犬隻勇
直径２５．４鶴×厚さ２．１１ｍのＳＯ３３２９Ｊ２Ｌ
製鋼管に、鉄イオン濃度がｔｏｐｐｍになるように硫酸
第一鉄を添加した海水を流速１霞八ｅｃで１ケ月間通水
し、内表面にもらいｗＩＮを形成させた鋼管を試験片と
して用いた。このもらい請付鋼管内に鉄イオンが１１）
Ｐ鴎ならびにモリブデン酸イオン、タングステン酸イオ
ン、バナジン酸イオンの１種以上が所定の濃度になるよ
うに、硫酸第一鉄ならびに各酸素酸のナトリウム塩を添
加した８０℃の海水を０．５ｍ／ｓｅｃの流速で２ケ月
間通水した後、その鋼管を半割りし、孔食発生の有無を
調査した。結果を第１表に示す。Inuzune Isamu diameter 25.4 cranes x thickness 2.11 m SO3329J2L
Seawater to which ferrous sulfate had been added so that the iron ion concentration was TOPPM was passed through the steel pipe at a flow rate of 1 8 EC for 1 month, and the steel pipe was used as a test specimen to form ferrous sulfuric acid on the inner surface. there was. There are iron ions in this steel pipe (11)
80°C seawater to which ferrous sulfate and sodium salts of each oxyacid were added was added to 0.5 m/s of seawater at a temperature of 80°C and ferrous sulfate and sodium salts of each oxyacid were added so that the concentration of one or more of P-glue and one or more of molybdate ions, tungstate ions, and vanadate ions was at a predetermined concentration. After water was passed through the pipe at a flow rate of 1.5 sec for 2 months, the steel pipe was cut in half and the presence or absence of pitting corrosion was investigated. The results are shown in Table 1.
第１表
第１表に示すように、本発明例では全く孔食の発生は見
られなかったが、モリブデン酸イオン、タングステン酸
イオン、およびバナジン酸イオンのいずれも添加しない
場合には孔食が発生し、合計で１ ｐｐｍ未満の添加で
は、孔食の程度が軽くはなったが、微小の孔食が発生し
た。Table 1 As shown in Table 1, no pitting corrosion was observed in the examples of the present invention, but pitting corrosion occurred when none of molybdate ions, tungstate ions, and vanadate ions were added. When the total amount of addition was less than 1 ppm, although the degree of pitting corrosion became lighter, minute pitting corrosion occurred.
このように、本発明の方法は、鉄イオンを注入した海水
を使用した場合に、管内表面へのもらい鯖の付着が避け
られないステンレス鋼製海水熱交換器の防食対策として
、非常に有効であることがわかる。As described above, the method of the present invention is very effective as a corrosion prevention measure for stainless steel seawater heat exchangers where it is inevitable that mackerel will adhere to the inner surface of the pipes when seawater injected with iron ions is used. I understand that there is something.
なお、以上においては海水が管内を流通する場合につい
て説明したが、海水が管外面側を流通する熱交換器の場
合であっても、本発明の方法が有効であることはいうま
でもない。In addition, although the case where seawater flows through the pipe has been described above, it goes without saying that the method of the present invention is effective even in the case of a heat exchanger in which seawater flows on the outside surface of the pipe.
（発明の効果）
本発明は、海水中にモリブデン酸イオン、タングステン
酸イオン、およびバナジン酸イオンの１種あるいは２種
以上をｔｐｐ−以上の合計濃度となるように添加すると
いう簡単な方法により、海水を冷却水として使用する化
学工業用ステンレス鋼製熱交換器の管内面のもらい錆に
よる局部腐食を効果的に防止す・ることができる、安価
で有効な防食方法である。(Effects of the Invention) The present invention uses a simple method of adding one or more of molybdate ions, tungstate ions, and vanadate ions to seawater to a total concentration of tpp- or more. This is an inexpensive and effective corrosion prevention method that can effectively prevent local corrosion caused by rust on the inner surface of the tubes of stainless steel heat exchangers for the chemical industry that use seawater as cooling water.
Claims (1)
リブデン酸イオン（ＭｏＯ＿４＾２＾−）、タングステ
ン酸イオン（ＷＯ＿４＾２＾−）、およびバナジン酸イ
オン（ＶＯ＿３＾−）から選ばれた１種あるいは２種以
上を添加することを特徴とする、ステンレス鋼製海水熱
交換器の防食方法。Selected from molybdate ion (MoO_4^2^-), tungstate ion (WO_4^2^-), and vanadate ion (VO_3^-) so as to have a concentration of 1 ppm or more in seawater for cooling water. A method for preventing corrosion of a stainless steel seawater heat exchanger, characterized by adding one or more kinds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1845189A JPH02197587A (en) | 1989-01-27 | 1989-01-27 | Method for preventing corrosion of seawater cooling type heat exchanger made of stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1845189A JPH02197587A (en) | 1989-01-27 | 1989-01-27 | Method for preventing corrosion of seawater cooling type heat exchanger made of stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02197587A true JPH02197587A (en) | 1990-08-06 |
Family
ID=11971993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1845189A Pending JPH02197587A (en) | 1989-01-27 | 1989-01-27 | Method for preventing corrosion of seawater cooling type heat exchanger made of stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02197587A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001086023A3 (en) * | 2000-05-05 | 2002-05-10 | Henkel Kgaa | Inhibition of pitting and crevice corrosion |
| JP2020169364A (en) * | 2019-04-04 | 2020-10-15 | 日立Ｇｅニュークリア・エナジー株式会社 | Liquid treatment system and adsorption system |
-
1989
- 1989-01-27 JP JP1845189A patent/JPH02197587A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001086023A3 (en) * | 2000-05-05 | 2002-05-10 | Henkel Kgaa | Inhibition of pitting and crevice corrosion |
| JP2020169364A (en) * | 2019-04-04 | 2020-10-15 | 日立Ｇｅニュークリア・エナジー株式会社 | Liquid treatment system and adsorption system |
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