JPH0159039B2 - - Google Patents
Info
- Publication number
- JPH0159039B2 JPH0159039B2 JP57066113A JP6611382A JPH0159039B2 JP H0159039 B2 JPH0159039 B2 JP H0159039B2 JP 57066113 A JP57066113 A JP 57066113A JP 6611382 A JP6611382 A JP 6611382A JP H0159039 B2 JPH0159039 B2 JP H0159039B2
- Authority
- JP
- Japan
- Prior art keywords
- scale
- sulfur
- sodium hydroxide
- hydrazine
- sodium metasilicate
- 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
Links
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 54
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims description 21
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 19
- 239000011593 sulfur Substances 0.000 claims description 12
- 229910052717 sulfur Inorganic materials 0.000 claims description 12
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 10
- 239000004115 Sodium Silicate Substances 0.000 claims description 9
- 235000019795 sodium metasilicate Nutrition 0.000 claims description 9
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 9
- 150000003464 sulfur compounds Chemical class 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims 1
- 238000005260 corrosion Methods 0.000 description 8
- 230000007797 corrosion Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 229910000838 Al alloy Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- QGJOPFRUJISHPQ-NJFSPNSNSA-N carbon disulfide-14c Chemical compound S=[14C]=S QGJOPFRUJISHPQ-NJFSPNSNSA-N 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 240000007124 Brassica oleracea Species 0.000 description 1
- 235000003899 Brassica oleracea var acephala Nutrition 0.000 description 1
- 235000012905 Brassica oleracea var viridis Nutrition 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- NOKUIIONGVTVQM-UHFFFAOYSA-N hydrazine sulfide Chemical compound SN=N NOKUIIONGVTVQM-UHFFFAOYSA-N 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920001021 polysulfide Polymers 0.000 description 1
- 239000005077 polysulfide Substances 0.000 description 1
- 150000008117 polysulfides Polymers 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
本発明は壁面に付着した単体イオウおよびイオ
ウ化合物を主体とするイオウスケールの安全かつ
迅速に溶解剥離するイオウスケールの化学的除去
方法に関する。
地熱発電所の冷却水系統の機器、配管や温泉水
を輸送する配管などのように、硫化水素を含む水
で運転される機器やその配管（材質はいずれも炭
素鋼、不銹鋼、アルミニウム合金）の壁面に硫化
水素から生成した熱伝導率の悪い単体イオウやイ
オウ化合物が付着し、それによつて伝導阻外やそ
のスケールによる配管などの閉塞も考えられる。
従つて、この種のスケールが付着する機器の稼動
率を高めるためには、該スケールの除去が必要で
ある。
しかしながら、単体イオウは化学的に非常に安
定で、直接溶解するためには取扱いの危険な二硫
化炭素を使用するしかない。そのため、機械的な
手段で、除去する方法が一般的であるが、該スケ
ールが乾燥すると、強固なスケールとなり、機械
的な除去法ですら困難になる。
本発明は上記の従来方法の欠点を解決し、壁面
に付着した単体イオウおよびイオウ化合物を主体
とするイオウスケールを安全かつ迅速に溶解剥離
するイオウスケールの化学的除去方法を提供する
もので、その要旨とするところは、ヒドラジン５
％以上および水酸化ナトリウムまたはメタケイ酸
ナトリウム0.1〜1.0％を含む水溶液を壁面に付着
した単体イオウおよびイオウ化合物を主体とする
イオウスケールに接触させることを特徴とするイ
オウスケールの化学的除去方法、にある。
本発明で使用されるヒドラジン５％以上及び水
酸化ナトリウムまたはメタケイ酸ナトリウム0.1
〜1.0％を含む水溶液の単体イオウおよびイオウ
化合物を主体とするスケールを溶解剥離する反応
機構について述べると、次のごとくである。
(1) ヒドラジン（N2H4）の作用
ヒドラジンは次の式で示すように、アルカリ
溶液中で化学的に活性化が高くなるので、これ
をス
3N2H4＋2S→（N2H4）2・H2S＋N2＋H2S
ケールの主成分である単体イオウに反応させ、
イオウ粒子表面をヒドラジン硫化物に変える。
また、このとき発生するN2ガスやH2Sガスは
ルーズな構造に変つた該スケールの崩壊を促進
する。ヒドラジンの添加量５％未満ではこの効
果はほとんどない。
(2) 水酸化ナトリウム（NaOH）の作用
水酸化ナトリウムはヒドラジンの該スケール
中への浸透性と還元剥離効果を高め、水酸化ナ
トリウムで溶けた硫化物（Na2S）がさらにイ
オウを溶かし、Na2S2、Na2S5、Na2S9などの
多硫化物をつくる。
また系統内にアルミニウム合金で構成された
機器や配管がある場合、水酸化ナトリウム代り
に、メタケイ酸ナトリウム（Na2SiO3）を0.1
〜1.0％添加してもよい。
水酸化ナトリウム、メタケイ酸ナトリウムの
添加量が0.1未満では上記の効果がなく、１％
を越えると母材の腐食が大きくなる。
次に、本発明を実施例によつてさらに具体的に
説明する。
実施例
スケール付着量20mg／cm2の実械配管を温度20℃
で５％以上のヒドラジンおよび0.1〜1.0％の水酸
化ナトリウムを含む溶液に24時間浸漬静置処理す
ると、スケールは完全に除去できる。なお、ヒド
ラジン５％以上、水酸化ナトリウム0.1〜1.0％の
範囲内でのスケール除去率および母材の腐食率を
第１表に示す。
The present invention relates to a method for chemically removing sulfur scale, which safely and quickly dissolves and peels off sulfur scale mainly consisting of elemental sulfur and sulfur compounds attached to a wall surface. Equipment and piping (all made of carbon steel, stainless steel, and aluminum alloy) that are operated with water containing hydrogen sulfide, such as cooling water system equipment and piping in geothermal power plants and piping that transports hot spring water, etc. Elemental sulfur and sulfur compounds with poor thermal conductivity generated from hydrogen sulfide may adhere to the walls, which may lead to conduction failure or blockage of pipes due to the scale.
Therefore, in order to increase the operating rate of equipment to which this type of scale adheres, it is necessary to remove the scale. However, elemental sulfur is chemically very stable, and the only way to directly dissolve it is to use carbon disulfide, which is dangerous to handle. Therefore, it is common to remove the scale by mechanical means, but when the scale dries, it becomes a strong scale, making even mechanical removal difficult. The present invention solves the drawbacks of the above-mentioned conventional methods and provides a method for chemically removing sulfur scale, which safely and quickly dissolves and peels off sulfur scale mainly consisting of simple sulfur and sulfur compounds attached to walls. The gist is that hydrazine 5
% or more and 0.1 to 1.0% of sodium hydroxide or sodium metasilicate to a sulfur scale mainly composed of elemental sulfur and sulfur compounds attached to a wall surface. be. 5% or more of hydrazine and 0.1 sodium hydroxide or sodium metasilicate used in the present invention
The reaction mechanism for dissolving and peeling off scale mainly composed of elemental sulfur and sulfur compounds in an aqueous solution containing ~1.0% is as follows. (1) Effect of hydrazine (N 2 H 4 ) As shown in the following formula, hydrazine is chemically highly activated in an alkaline solution. ) 2・H 2 S + N 2 + H 2 S Reacts with elemental sulfur, which is the main component of kale,
Converts the surface of sulfur particles to hydrazine sulfide.
Further, the N 2 gas and H 2 S gas generated at this time promote the collapse of the scale, which has changed into a loose structure. This effect is almost absent when the amount of hydrazine added is less than 5%. (2) Effect of sodium hydroxide (NaOH) Sodium hydroxide increases the permeability of hydrazine into the scale and the reduction removal effect, and the sulfide (Na 2 S) dissolved in sodium hydroxide further dissolves sulfur. Creates polysulfides such as Na 2 S 2 , Na 2 S 5 and Na 2 S 9 . Also, if there are equipment or piping made of aluminum alloy in the system, use 0.1% sodium metasilicate (Na 2 SiO 3 ) instead of sodium hydroxide.
~1.0% may be added. If the amount of sodium hydroxide or sodium metasilicate added is less than 0.1, the above effect will not be achieved, and 1%
Exceeding this will result in greater corrosion of the base metal. Next, the present invention will be explained in more detail with reference to Examples. Example: Actual piping with a scale adhesion amount of 20 mg/cm 2 at a temperature of 20°C
Scale can be completely removed by immersing and standing in a solution containing 5% or more hydrazine and 0.1 to 1.0% sodium hydroxide for 24 hours. Table 1 shows the scale removal rate and base material corrosion rate within the range of 5% or more of hydrazine and 0.1 to 1.0% of sodium hydroxide.
【表】【table】
【表】
比較例
実施例１と同一配管を５％塩酸にインヒビター
を加えた溶液（ボイラーの蒸発管に付着したスケ
ールを除去するのに使用されているもの）で実施
例と同一条件で処理したところ、スケールの除去
率は37％程度で完全に除去することができなかつ
た。
なお、比較例の２例の結果を次の第２表に示
す。[Table] Comparative Example The same piping as in Example 1 was treated with a solution of 5% hydrochloric acid and an inhibitor (used to remove scale attached to boiler evaporation tubes) under the same conditions as in Example. However, the scale removal rate was about 37%, and it was not possible to completely remove the scale. The results of two comparative examples are shown in Table 2 below.
【表】
上記の２例ではスケールが溶解しなかつた。
また、スケール除去時の母材腐食量について述
べる。
母材が炭素鋼、不銹鋼については腐食量は＜
0.02mg／cm2・48Hrで無視できる程度であるが、
アルミニウム合金については図に示すように、水
酸化ナトリウム濃度を0.1％にすれば腐食量は0.1
mg／cm2・Hrとなる。この場合、水酸化ナトリウ
ムの代りに、メタケイ酸ナトリウムを使用する
と、腐食量をさらに小さくできる。
本発明の効果は次の通りである。
(1) ５％以上のヒドラジンおよび0.1〜1.0％の水
酸化ナトリウムを含む水溶液で、従来法では化
学的に除去することが困難であつたイオウスケ
ールを完全に付着面から溶解剥離して除去する
ことができる。
(2) 本発明の除去方法は常温で処理できかつ流速
も必要でない。
(3) 構成材料によつて、水酸化ナトリウムの代り
に、メタケイ酸ナトリウムを用いることができ
る。
(4) 洗浄時の構成材料の腐食量は無視できる程度
で問題ない。
(5) 引火性のつよい二硫化炭素を使用する必要が
ないので、イオウスケール除去作業上の危険が
少ない。[Table] In the two examples above, the scale did not dissolve. We will also discuss the amount of base metal corrosion during scale removal. If the base material is carbon steel or stainless steel, the amount of corrosion is <
Although it is negligible at 0.02mg/cm 2・48Hr,
For aluminum alloys, as shown in the figure, if the sodium hydroxide concentration is 0.1%, the amount of corrosion will be 0.1%.
mg/cm 2・Hr. In this case, if sodium metasilicate is used instead of sodium hydroxide, the amount of corrosion can be further reduced. The effects of the present invention are as follows. (1) Using an aqueous solution containing 5% or more hydrazine and 0.1 to 1.0% sodium hydroxide, sulfur scale, which was difficult to chemically remove using conventional methods, is completely dissolved and peeled off from the adhering surface. be able to. (2) The removal method of the present invention can be processed at room temperature and does not require a flow rate. (3) Depending on the constituent materials, sodium metasilicate may be used instead of sodium hydroxide. (4) The amount of corrosion of the constituent materials during cleaning is negligible and is not a problem. (5) Since there is no need to use highly flammable carbon disulfide, there is less danger in the sulfur scale removal work.
添付図は0.1〜1.0％のNaOH（又は、メタケイ
酸ナトリウム）と５％N2H4を含む溶液中での
NaOH（又は、メタケイ酸ナトリウム）の濃度と
アルミニウム合金の腐食率の関係を示すグラフ
図、曲線はNaOHの場合、曲線はメタケイ
酸ナトリウムの場合である。
The attached figure shows the reaction in a solution containing 0.1-1.0% NaOH (or sodium metasilicate) and 5% N2H4 .
A graph showing the relationship between the concentration of NaOH (or sodium metasilicate) and the corrosion rate of aluminum alloy. The curve is for NaOH and the curve is for sodium metasilicate.
Claims (1)
またはメタケイ酸ナトリウム0.1〜1.0％を含む水
溶液を壁面に付着した単体イオウおよびイオウ化
合物を主体とするイオウスケールに接触させるこ
とを特徴とするイオウスケールの化学的除去方
法。1. Chemical removal of sulfur scale, characterized by bringing an aqueous solution containing 5% or more of hydrazine and 0.1 to 1.0% of sodium hydroxide or sodium metasilicate into contact with sulfur scale, which is mainly composed of elemental sulfur and sulfur compounds attached to a wall surface. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6611382A JPS58183996A (en) | 1982-04-20 | 1982-04-20 | Chemical removal of sulfur scale |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6611382A JPS58183996A (en) | 1982-04-20 | 1982-04-20 | Chemical removal of sulfur scale |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58183996A JPS58183996A (en) | 1983-10-27 |
| JPH0159039B2 true JPH0159039B2 (en) | 1989-12-14 |
Family
ID=13306500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6611382A Granted JPS58183996A (en) | 1982-04-20 | 1982-04-20 | Chemical removal of sulfur scale |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58183996A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03646U (en) * | 1989-05-24 | 1991-01-08 | ||
| JPH052065Y2 (en) * | 1989-04-21 | 1993-01-19 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6872747B2 (en) * | 2017-01-17 | 2021-05-19 | 株式会社片山化学工業研究所 | Sulfur scale cleaning agent and sulfur scale cleaning method using it |
-
1982
- 1982-04-20 JP JP6611382A patent/JPS58183996A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH052065Y2 (en) * | 1989-04-21 | 1993-01-19 | ||
| JPH03646U (en) * | 1989-05-24 | 1991-01-08 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58183996A (en) | 1983-10-27 |
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