JP2681213B2 - Anticorrosion method for steel pipes for geothermal wells - Google Patents

Anticorrosion method for steel pipes for geothermal wells

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Publication number
JP2681213B2
JP2681213B2 JP1079482A JP7948289A JP2681213B2 JP 2681213 B2 JP2681213 B2 JP 2681213B2 JP 1079482 A JP1079482 A JP 1079482A JP 7948289 A JP7948289 A JP 7948289A JP 2681213 B2 JP2681213 B2 JP 2681213B2
Authority
JP
Japan
Prior art keywords
corrosion
geothermal
hot water
steel pipes
steel pipe
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.)
Expired - Fee Related
Application number
JP1079482A
Other languages
Japanese (ja)
Other versions
JPH02258987A (en
Inventor
澄夫 赤司
和緒 廣渡
真生 山内
達也 小泉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyushu Electric Power Co Inc
Original Assignee
Kyushu Electric Power Co Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kyushu Electric Power Co Inc filed Critical Kyushu Electric Power Co Inc
Priority to JP1079482A priority Critical patent/JP2681213B2/en
Publication of JPH02258987A publication Critical patent/JPH02258987A/en
Application granted granted Critical
Publication of JP2681213B2 publication Critical patent/JP2681213B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/16—Sulfur-containing compounds

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Description

【発明の詳細な説明】 イ）産業上の利用分野 本発明は地熱井戸用鋼管の防食方法に関するものであ
る。更に詳しくは、地熱発電用井戸等，地熱井戸用の鋼
管内に、所定の腐食抑制剤を注入することを特徴とする
当該鋼管の防食方法に関するものである。TECHNICAL FIELD The present invention relates to a method for preventing corrosion of a steel pipe for a geothermal well. More specifically, the present invention relates to a method for preventing corrosion of a steel pipe, which is characterized by injecting a predetermined corrosion inhibitor into a steel pipe for a geothermal well such as a geothermal power generation well.

ロ）発明が解決しようとする問題点 従来、地熱発電はクリーンなエネルギーとして注目さ
れ、世界各地で開発が進んでいる。その発電システムに
は、若干の差異はあるものの、エネルギー源である蒸気
及び熱水を得る方法としては鋼管で構成された井戸が利
用されている。(B) Problems to be solved by the invention Geothermal power generation has hitherto attracted attention as clean energy and is being developed all over the world. Although there are some differences in the power generation system, a well made of steel pipe is used as a method for obtaining steam and hot water which are energy sources.

しかし、地熱資源は、地質的条件によって、蒸気及び
熱水に含有される種々の成分組成が異なり井戸を構成す
る鋼管の寿命に大きく影響を及ぼすことが知られてい
る。However, it is known that geothermal resources greatly affect the lifespan of steel pipes forming wells, because the composition of various components contained in steam and hot water differs depending on geological conditions.

地熱水の主な化学成分としては、Na+,K+,Ca2+,Mg2+,S
iO2,などの他に、SO4 2-,HCO3 -,Cl-などがあり、これら
の成分比率によっては、熱水のpHが酸性側を示すものも
少なくない。よって、膨大な費用をかけて掘削した井戸
でも、酸性を示すものは鋼管の腐食が著しく、場合によ
っては掘削と同時に実用運転することなしに封じられる
ことも珍しくないのが実状である。また、高温岩体発電
方式では、地熱の利用により注入水を熱水，蒸気にする
ものであるため、地下の酸性成分を抽出して、酸性の熱
水，蒸気となる可能性を含んでいる。The main chemical components of geothermal water are Na + , K + , Ca 2+ , Mg 2+ , S
In addition to iO 2 , etc., there are SO 4 2− , HCO 3 − , Cl −, etc., and depending on the ratio of these components, the pH of hot water often shows an acidic side. Therefore, even in wells that have been drilled at enormous costs, steel pipes that exhibit acidity are significantly corroded, and in some cases it is not uncommon that they are sealed without operating the pipes at the same time as drilling. In addition, in the HDR pyroelectric power generation method, since the injected water is converted into hot water and steam by utilizing geothermal heat, there is a possibility that acidic components in the underground will be extracted and become acidic hot water and steam. .

熱水による腐食は酸性成分による化学的な金属の溶解
（コロージョン）と、蒸気を含む熱水の二相流体による
物理的な力が作用して起こる金属の侵食（エロージョ
ン）とが考えられる。Corrosion by hot water is considered to be chemical dissolution of metal by an acidic component (corrosion) and erosion of metal caused by physical force of a two-phase fluid of hot water containing steam (erosion).

しかし通常pHが酸性を示さない井戸では、エロージョ
ンが同様に起こると考えられるにもかかわらず充分に実
用運転されていることから、コロージョンを防止するこ
とがもっとも重要な問題とされる。しかも井戸の内部温
度が高温であるため腐食反応が著しく速いものとなって
いる。もちろん、温泉程度の低温ならば各種の防食方法
があるが、発電等に使用されるような高温井戸における
鋼管用の防食方法は現在のところ見当たらない。However, in wells where the pH does not normally show acidity, erosion is considered to occur similarly, but since it is operating sufficiently practically, prevention of corrosion is the most important problem. Moreover, since the internal temperature of the well is high, the corrosion reaction is extremely fast. Of course, there are various anticorrosion methods at temperatures as low as hot springs, but no anticorrosion method for steel pipes in high temperature wells such as those used for power generation is currently found.

（ハ）発明の構成 本発明者らは、鋭意研究の結果、下記一般式で示され
るベンゼン環にアルキレンチオシアナートを導入した腐
食抑制剤を地熱井戸用鋼管内、特に地熱発電用井戸の鋼
管内へ直接注入することによって、高温であるにもかか
わらず、著しく効果的に鋼管内部の腐食を抑制すること
を見い出し、本発明に至った。(C) Structure of the invention As a result of earnest research, the present inventors have found that a corrosion inhibitor in which an alkylene thiocyanate is introduced into a benzene ring represented by the following general formula is used in a steel pipe for a geothermal well, particularly a steel pipe for a geothermal power generation well. The present invention has been found to be extremely effective in suppressing the corrosion inside the steel pipe by directly injecting it into the steel pipe even though the temperature is high.

［式中ｍは１〜5,nは２〜３である。］ 注入方法としては、大口径の井戸用鋼管の内部へ小口
径の注入管を導入し井戸の深部から連続あるいは断続的
に注入する方法が考えられるが、井戸の条件によっては
浅部注入でも充分に効果を発揮するものと考えられる。
つまり、二相流を形成すると思われるところよりも、深
部であれば効果的である。 [In the formula, m is 1 to 5 and n is 2 to 3. ] As an injection method, it is possible to introduce a small-diameter injection pipe into a large-diameter steel pipe for continuous or intermittent injection from the deep part of the well, but depending on the conditions of the well, shallow injection may be sufficient. It is considered to be effective for.
In other words, it is more effective in deeper areas than where two-phase flow seems to be formed.

本発明において使用される腐食抑制剤としてはｏ−キ
シレンビスチオシアナート,m−キシレンビスチオシアナ
ート,p−キシレンビスチオシアナート,p−フェニレンビ
ス（1,2−エタンジイルチオシアナート）,p−フェニレ
ンビス（1,4−ブタンジイルチオシアナート）等があげ
られる。Examples of the corrosion inhibitor used in the present invention include o-xylenebisthiocyanate, m-xylenebisthiocyanate, p-xylenebisthiocyanate, p-phenylenebis (1,2-ethanediylthiocyanate). , p-phenylene bis (1,4-butanediyl thiocyanate) and the like.

腐食抑制剤は使用の際の分散性を考慮して、界面活性
剤との併用が望ましく、更には可溶化のために溶剤を一
部用いても差しつかえない。The corrosion inhibitor is preferably used in combination with a surfactant in consideration of dispersibility at the time of use, and a solvent may be partially used for solubilization.

（ニ）作用 本発明の方法は地熱水量に対して腐食抑制剤を0.001
〜５重量パーセント、好ましくは経済的な点も考慮して
0.001〜0.1パーセント添加することにより、安定に鋼管
内部に保護皮膜を形成させ、素地金属の溶解を抑制、防
止するものと思われる。その皮膜形成は、チオシアナー
ト基の酸化的な付加反応によるもので、特に高温下でも
破壊されにくい強固な皮膜と考えられる。(D) Action The method of the present invention uses a corrosion inhibitor of 0.001 against the amount of geothermal water.
~ 5 weight percent, preferably also for economic considerations
It is believed that the addition of 0.001 to 0.1 percent stably forms a protective film inside the steel pipe and suppresses or prevents the dissolution of the base metal. The film formation is due to the oxidative addition reaction of the thiocyanate group, and is considered to be a strong film that is not easily broken even at high temperatures.

（ホ）実施例 以下実施例を挙げて、本発明の防食方法の有効性を説
明する。(E) Examples The effectiveness of the anticorrosion method of the present invention will be described with reference to the following examples.

〈オートクレーブ試験〉 地熱井戸の模擬試験法として評価した。表−１に示す
組成の井戸からの採取水300mlを塩酸でpH2.0に調整し、
ガラス製オートクレーブにて150℃で１時間の腐食試験
を行う。<Autoclave test> This was evaluated as a simulated test method for geothermal wells. 300 ml of water collected from the well having the composition shown in Table-1 was adjusted to pH 2.0 with hydrochloric acid,
Carry out a corrosion test at 150 ° C for 1 hour in a glass autoclave.

テストピースの材質はSPCC50×10×1mmとして、熱水
は撹拌機で強く混合させる。腐食抑制剤の分散性を向上
させるため、ノニオン系の界面活性剤を少量使用する。
評価は以下に示す算出方法で抑制率として表わし、添加
量とともに結果を表２に示す。The material of the test piece is SPCC 50 x 10 x 1 mm, and hot water is mixed strongly with a stirrer. A small amount of nonionic surfactant is used to improve the dispersibility of the corrosion inhibitor.
The evaluation is expressed as the inhibition rate by the following calculation method, and the results are shown in Table 2 together with the addition amount.

〈現地テスト〉 表−１に示す組成の熱水を、熱水量3.5l/min,蒸気量3
90l/minの二相流体で第１図に示すようなフローで連続
的に120時間供給し、腐食抑制剤を注入した場合と注入
しない場合でのテストピースの腐食減量を測定し、抑制
率（％）を算出した。即ち、ライン１から供給される二
相流体に、強制的にpHを下げるためタンク３の塩酸をポ
ンプ４を介して混合器２へ供給し、熱水出口ライン14の
pHを2.6に調整した。混合器２で酸性となった二相流体
は、ライン５を通りライン6,7に分岐してテスト管8,9に
供給され、ライン12で合流して冷却器13で冷却され温水
としてライン14から排出される。 <Field test> Hot water with the composition shown in Table-1 was used with a hot water amount of 3.5 l / min and a steam amount of 3
The 90% / min two-phase fluid was continuously supplied for 120 hours in the flow shown in Fig. 1, and the corrosion weight loss of the test piece with and without the corrosion inhibitor was measured, and the inhibition rate ( %) Was calculated. That is, to the two-phase fluid supplied from the line 1, the hydrochloric acid in the tank 3 is forcibly supplied to the mixer 2 via the pump 4 in order to lower the pH, and the hot water outlet line 14
The pH was adjusted to 2.6. The two-phase fluid that has become acidic in the mixer 2 is branched into the lines 6 and 7 through the line 5 and is supplied to the test tubes 8 and 9, and is joined in the line 12 to be cooled in the cooler 13 to be the hot water in the line 14. Emitted from.

ライン６には腐食抑制剤調整タンク10で、乳化剤と水
とで10％に乳化されたｐ−キシレンビスチオシアナート
をポンプ11を介してテスト管８へ供給される。供給量は
熱水量に対して腐食抑制剤として50ppm,100ppmの２濃度
で試験した。条件は下記のとおりである。A line 6 is provided with a corrosion inhibitor adjusting tank 10 in which 10% p-xylenebisthiocyanate emulsified with an emulsifier and water is supplied to a test tube 8 via a pump 11. The supply amount was tested at two concentrations of 50 ppm and 100 ppm as a corrosion inhibitor against the amount of hot water. The conditions are as follows.

試験条件 熱水（二相流体）pH 2.6 〃 温度160℃ テスト管 STPG38 外径34mm（内径27mm）×50mm 抑制率の算出は、オートクレーブ試験と同様に行う。
比較例の腐食減量率はテスト管９の腐食減量であり、実
施例はテスト管８の腐食減量である。Test conditions Hot water (two-phase fluid) pH 2.6 〃 Temperature 160 ℃ Test tube STPG38 Outer diameter 34mm (inner diameter 27mm) x 50mm The suppression rate is calculated in the same way as the autoclave test.
The corrosion weight loss rate of the comparative example is the corrosion weight loss of the test tube 9, and the example is the corrosion weight loss of the test tube 8.

結果は表−３に示した。 The results are shown in Table 3.

（ヘ）発明の効果 本発明の方法によれば、地熱用鋼管に対する防食効果
が極めて大きいことが判明した。 (F) Effect of the invention It has been found that the method of the present invention has an extremely large anticorrosion effect on the geothermal steel pipe.

【図面の簡単な説明】[Brief description of the drawings]

第１図は、本発明の実施例の現地テストで採用したフロ
ーダイアグラムである。FIG. 1 is a flow diagram adopted in the field test of the embodiment of the present invention.

フロントページの続き (72)発明者 小泉 達也 山口県熊毛郡平生町大字平生村742番地 ―１ 審査官 刑部 俊 (56)参考文献 特開 昭51−92743（ＪＰ，Ａ) 特開 昭56−70190（ＪＰ，Ａ) 実開 昭56−143572（ＪＰ，Ｕ) 特公 平６−37709（ＪＰ，Ｂ２)Continuation of the front page (72) Inventor Tatsuya Koizumi 742, Hirayo-mura, Hirayo-cho, Kumage-gun, Yamaguchi -1 Examiner Shun Hanbe (56) References JP-A-51-92743 (JP, A) JP-A-56-70190 (JP, A) Actual development Sho 56-143572 (JP, U) Japanese Patent Publication 6-37709 (JP, B2)

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】下記一般式で示される化合物を注入してな
る地熱井戸用鋼管の防食方法 ［式中、ｍは１〜5,nは２〜３である］1. A method for preventing corrosion of a steel pipe for a geothermal well by injecting a compound represented by the following general formula: [In the formula, m is 1 to 5 and n is 2 to 3]
JP1079482A 1989-03-29 1989-03-29 Anticorrosion method for steel pipes for geothermal wells Expired - Fee Related JP2681213B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1079482A JP2681213B2 (en) 1989-03-29 1989-03-29 Anticorrosion method for steel pipes for geothermal wells

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1079482A JP2681213B2 (en) 1989-03-29 1989-03-29 Anticorrosion method for steel pipes for geothermal wells

Publications (2)

Publication Number Publication Date
JPH02258987A JPH02258987A (en) 1990-10-19
JP2681213B2 true JP2681213B2 (en) 1997-11-26

Family

ID=13691114

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1079482A Expired - Fee Related JP2681213B2 (en) 1989-03-29 1989-03-29 Anticorrosion method for steel pipes for geothermal wells

Country Status (1)

Country Link
JP (1) JP2681213B2 (en)

Also Published As

Publication number Publication date
JPH02258987A (en) 1990-10-19

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