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EP0215655B1 - Method of inhibiting boiler corrosion and compositions for it - Google Patents

Method of inhibiting boiler corrosion and compositions for it Download PDF

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Publication number
EP0215655B1
EP0215655B1 EP86307064A EP86307064A EP0215655B1 EP 0215655 B1 EP0215655 B1 EP 0215655B1 EP 86307064 A EP86307064 A EP 86307064A EP 86307064 A EP86307064 A EP 86307064A EP 0215655 B1 EP0215655 B1 EP 0215655B1
Authority
EP
European Patent Office
Prior art keywords
oxygen
corrosion
trihydroxybenzene
compositions
boiler feedwater
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 - Lifetime
Application number
EP86307064A
Other languages
German (de)
French (fr)
Other versions
EP0215655A1 (en
Inventor
John D. Zupanovich
Dennis J. Sepelak
Lois J. Neil
Rabindra K. Sinha
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.)
Ecc Specialty Chemicals Inc english China Clays
Calgon Corp
Original Assignee
Calgon Corp
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Filing date
Publication date
Application filed by Calgon Corp filed Critical Calgon Corp
Priority to AT86307064T priority Critical patent/ATE49424T1/en
Publication of EP0215655A1 publication Critical patent/EP0215655A1/en
Application granted granted Critical
Publication of EP0215655B1 publication Critical patent/EP0215655B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • C23F11/12—Oxygen-containing compounds
    • 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
    • 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
    • C23F11/14—Nitrogen-containing compounds
    • C23F11/144—Aminocarboxylic acids

Definitions

  • This invention relates to the inhibition of corrosion in boiler feedwater systems and boilers due to the presence of dissolved oxygen. It is also concerned with compositions for such use.
  • the first product of corrosion may be ferric oxide, which is only loosely adherent and blocks off areas to oxygen access. These areas become anionic and iron oxide couples are set up. The iron under the oxide deposit then dissolves, and pitting develops, which thus aggravates corrosion.
  • the severity of attack by oxygen will depend on the concentration of dissolved oxygen in the water, and the pH and temperature of the water. As the water temperature increases, corrosion in feed lines, heaters, boilers, steam and return lines made of iorn and steel increases.
  • a major approach to reducing oxygen in boiler feedwater is mechanical deaeration. Efficient mechanical deaeration can reduce dissolved oxygen to as low as 5-10 ppb (parts per thousand million) in industrial plants and 2-3 ppb in utility operations. However, even with this trace amount of oxygen, some corrosion may occur in boilers. Removal of the last traces of oxygen from boiler feedwater is generally accomplished by the addition of chemicals that react with oxygen and that are hereinafter referred to as oxygen scavangers.
  • oxygen scavengers e.g. sodium sulphite, hyrazine, diethylhydroxylamine, carbohydrazide and hydroquinone, as disclosed in numerous U.S. Patent Specifications.
  • US-A-3 551 349 discloses the use of quinones, particularly hydroquinone, as catalysts for the hydrazine-oxygen reaction;
  • US-A-4 096 090 discloses the use of hydrazine compounds, a catalytic organometallic complex, and preferably a quinone compound for deoxygenating feedwater;
  • US-A-3 808 138 discloses the use of cobalt maleic acid hydrazide with hydrazine for oxygen removal;
  • US-A-3 962 113 discloses the use of organic-substituted hydrazines such as monoalkyl hydrazines, dialkyl hydrazines and trialkyl hydrazines as oxygen scavengers.
  • hydrazine and related compounds include toxicity and suspected carcinogenicity.
  • Hydrazine is toxic if inhaled and is also an irritant to the eyes and skin.
  • Carbohydrazide which is a derivative of hydrazine, decomposes to form hydrazine and carbon dioxide at temperatures above 360°F (180°C).
  • US-A-4 269 717 discloses the use of carbohydrazide as an oxygen scavenger and metal passivator.
  • US-A-4 278 635 and US-A-4 282 111 disclose the use of hydroquinone, as well as other dihydroxy, diamino and amino hydroxy benzenes, as oxygen scavengers; US-A-4 279 767 and US-A-4 487 708 disclose the use of hydroquinone and "mu-amines", which are defined as amines compatible with hydroquinone, e.g. methoxypropylamine; US-A-4 363 734 discloses the use of catalysed 1,3-dihydroxyacetone as an oxygen scavenger; US-A-4 419 327 discloses the use of amine or ammonia neutralized erythorbates as oxygen scavengers.
  • DEHA diethylhydroxylamine
  • US-A-4 192 844 discloses the use of methoxypropylamine and hydrazine as a corrosion inhibiting composition.
  • European Patent Specification EP-A-0 054 345 discloses the use of amino-phenol compounds or acid addition salts thereof as oxygen scavangers.
  • UK Patent Specification GB-A-2 138796 discloses the use of trivalent phenols, preferably pyrogallol, to improve the activity of hydrazine/trivalent-cobalt compositions.
  • the present invention provides a method for controlling corrosion in boilers and boiler feedwater systems comprising adding to boiler feedwater containing dissolved oxygen an additive comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1.
  • the present invention also provides a corrosion-inhibiting composition comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1.
  • the additive can be used in conjunction with hydrazine, but this is not preferred because of the toxicity of hydrazine.
  • the preferred dosage in order to inhibit corrosion is from 0.1 to 1,000 parts per million in the feedwater being treated, particularly from 1 to 100 parts per million.
  • the preferred mol ratio of the compound to dissolved O2 ranges from 0.01:1.0 to 100.1, particularly 0.1:1 to 20:1.
  • trihydroxybenzene compound can be used, viz. (and in order of preference) 1,2,3-trihydroxybenzene (pyrogallol), 1,2,4-trihydroxybenzene (hydroxyhydroquinone), or 1,3,5-trihydroxybenzene (phloroglucinol).
  • the trihydroxybenzene compounds can if desired be used in combination with each other or with other known corrosion inhibitors, e.g. filming amines and neutralizing amines.
  • compositions of the present invention can be used in the compositions of the present invention if desired.
  • Such compounds include catalysts such as cobalt, scale/deposit inhibitors such as chelants, dispersants, sequestrants, polyelectrolytes and organic or inorganic phosphates.
  • compositions may be fed to the boiler feedwater by any known means. Thus, they may be pumped into boiler feedwater tanks or lines, or added by some other suitable means. Though for convenience it is recommended that the trihydroxybenzene and hydroquinone be added as a composition, they may be added separately.
  • Examples 1-11 show the oxygen scavenging capability of pyrogallol. Pyrogallol, at the concentration indicated in Table I below, was added to a simulated boiler feedwater at a pH of 9.0 and at the temperature shown. Percent oxygen removal vlaues after 2, 4, 6, 8 and 10 minutes are shown in Table I.
  • Examples 12-14 show the oxygen scavenging capability of 1,2,4-trihydroxybenzene (phloroglucinol), which was added to simulated boiler feedwater at pH 9 and at the temperatures and dosages shown. Percent oxygen removal values after 2, 4, 6, 8 and 10 minutes are shown in Table II, below.
  • oxygen scavengers as boiler water corrosion inhibitors
  • results can be misleading. This is true because, in operating systems, oxygen is an intermediary in the corrosion reaction and the first product of corrosion is ferric oxide. Oxygen alone would not necessarily be detrimental were it not for this corrosion reaction.
  • the primary function of an oxygen scavenger may therefore be to reduce ferric ions to their original state. Under such conditions, it is the iron itself that is the primary "oxygen scavenger"; the dosing agent functions primarily as a reducing agent for ferric ions.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Description

  • This invention relates to the inhibition of corrosion in boiler feedwater systems and boilers due to the presence of dissolved oxygen. It is also concerned with compositions for such use.
  • Protection of boiler feedwater systems is becoming an increasingly important aspect of plant operation. The presence of dissolved oxygen in boiler feedwater is a primary cause of corrosion of material in contact with the water. Moreover, an increase in the quality of boiler feedwater results in savings of energy and consequently of cost for the total boiler system.
  • Historically, the action of dissolved gases such as oxygen and carbon dioxide has been a principal factor that leads to corrosion of water feed systems and boilers. In order to understand the role of dissolved gases in corrosion, it is necessary to understand the electrochemical nature of corrosion. Under most conditions, there is a tendency for iron to dissolve in water, and two electrons are released for each iron atom that dissolves These electrons are transferred to hydrogen ions present in the water, and the ions are reduced to elemental gaseous hydrogen. All action ceases at this point if the hydrogen remains on the surface of the metal, since a protective coating forms with the passage of electrons. However, any agent that increases the number of hydrogen ions present in the water, or that will cause the removal of the protective film, serves to increase the rate of corrosion.
  • The presence of oxygen in boiler feedwater causes a two-fold reaction to occur Some molecules of oxygen combine with displaced hydrogen, thereby exposing the metal to fresh attack. Other oxygen molecules combine with iron ions to form insoluble iron oxides.
  • The first product of corrosion may be ferric oxide, which is only loosely adherent and blocks off areas to oxygen access. These areas become anionic and iron oxide couples are set up. The iron under the oxide deposit then dissolves, and pitting develops, which thus aggravates corrosion.
  • The severity of attack by oxygen will depend on the concentration of dissolved oxygen in the water, and the pH and temperature of the water. As the water temperature increases, corrosion in feed lines, heaters, boilers, steam and return lines made of iorn and steel increases.
  • A major approach to reducing oxygen in boiler feedwater is mechanical deaeration. Efficient mechanical deaeration can reduce dissolved oxygen to as low as 5-10 ppb (parts per thousand million) in industrial plants and 2-3 ppb in utility operations. However, even with this trace amount of oxygen, some corrosion may occur in boilers. Removal of the last traces of oxygen from boiler feedwater is generally accomplished by the addition of chemicals that react with oxygen and that are hereinafter referred to as oxygen scavangers.
  • Several oxygen scavengers are known, e.g. sodium sulphite, hyrazine, diethylhydroxylamine, carbohydrazide and hydroquinone, as disclosed in numerous U.S. Patent Specifications.
  • Thus, US-A-3 551 349 discloses the use of quinones, particularly hydroquinone, as catalysts for the hydrazine-oxygen reaction; US-A-4 096 090 discloses the use of hydrazine compounds, a catalytic organometallic complex, and preferably a quinone compound for deoxygenating feedwater; US-A-3 808 138 discloses the use of cobalt maleic acid hydrazide with hydrazine for oxygen removal; and US-A-3 962 113 discloses the use of organic-substituted hydrazines such as monoalkyl hydrazines, dialkyl hydrazines and trialkyl hydrazines as oxygen scavengers. Disadvantages of hydrazine and related compounds include toxicity and suspected carcinogenicity. Hydrazine is toxic if inhaled and is also an irritant to the eyes and skin. Carbohydrazide, which is a derivative of hydrazine, decomposes to form hydrazine and carbon dioxide at temperatures above 360°F (180°C). US-A-4 269 717 discloses the use of carbohydrazide as an oxygen scavenger and metal passivator.
  • US-A-4 278 635 and US-A-4 282 111 disclose the use of hydroquinone, as well as other dihydroxy, diamino and amino hydroxy benzenes, as oxygen scavengers; US-A-4 279 767 and US-A-4 487 708 disclose the use of hydroquinone and "mu-amines", which are defined as amines compatible with hydroquinone, e.g. methoxypropylamine; US-A-4 363 734 discloses the use of catalysed 1,3-dihydroxyacetone as an oxygen scavenger; US-A-4 419 327 discloses the use of amine or ammonia neutralized erythorbates as oxygen scavengers. Additionally, diethylhydroxylamine (DEHA) has been used as an oxygen scavanger, and US-A-4 192 844 discloses the use of methoxypropylamine and hydrazine as a corrosion inhibiting composition. European Patent Specification EP-A-0 054 345 discloses the use of amino-phenol compounds or acid addition salts thereof as oxygen scavangers.
  • UK Patent Specification GB-A-2 138796 discloses the use of trivalent phenols, preferably pyrogallol, to improve the activity of hydrazine/trivalent-cobalt compositions.
  • The present invention provides a method for controlling corrosion in boilers and boiler feedwater systems comprising adding to boiler feedwater containing dissolved oxygen an additive comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1. The present invention also provides a corrosion-inhibiting composition comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1.
  • The additive can be used in conjunction with hydrazine, but this is not preferred because of the toxicity of hydrazine.
  • The preferred dosage in order to inhibit corrosion is from 0.1 to 1,000 parts per million in the feedwater being treated, particularly from 1 to 100 parts per million. The preferred mol ratio of the compound to dissolved O2 ranges from 0.01:1.0 to 100.1, particularly 0.1:1 to 20:1.
  • Any trihydroxybenzene compound can be used, viz. (and in order of preference) 1,2,3-trihydroxybenzene (pyrogallol), 1,2,4-trihydroxybenzene (hydroxyhydroquinone), or 1,3,5-trihydroxybenzene (phloroglucinol). The trihydroxybenzene compounds can if desired be used in combination with each other or with other known corrosion inhibitors, e.g. filming amines and neutralizing amines.
  • Other materials can be used in the compositions of the present invention if desired. Such compounds include catalysts such as cobalt, scale/deposit inhibitors such as chelants, dispersants, sequestrants, polyelectrolytes and organic or inorganic phosphates.
  • The compositions may be fed to the boiler feedwater by any known means. Thus, they may be pumped into boiler feedwater tanks or lines, or added by some other suitable means. Though for convenience it is recommended that the trihydroxybenzene and hydroquinone be added as a composition, they may be added separately.
  • The following examples are illustrative and do not limit the invention. Examples 1 to 29 are for comparison.
    • Examples 1-11
  • Examples 1-11 show the oxygen scavenging capability of pyrogallol. Pyrogallol, at the concentration indicated in Table I below, was added to a simulated boiler feedwater at a pH of 9.0 and at the temperature shown. Percent oxygen removal vlaues after 2, 4, 6, 8 and 10 minutes are shown in Table I.
    • Examples 12-14
  • Examples 12-14 show the oxygen scavenging capability of 1,2,4-trihydroxybenzene (phloroglucinol), which was added to simulated boiler feedwater at pH 9 and at the temperatures and dosages shown. Percent oxygen removal values after 2, 4, 6, 8 and 10 minutes are shown in Table II, below.
    • Examples 15-30
  • These examples compare the oxygen scavenging capabilities of several well-known oxygen scavengers with those of compositions comprising pyrogallol and hydroquinone. Results are shown in Table III, below.
    • Example 31
  • Although the traditional method of measuring the effectiveness of oxygen scavengers as boiler water corrosion inhibitors has been to measure the relative speed with which they react with dissolved oxygen, such results can be misleading. This is true because, in operating systems, oxygen is an intermediary in the corrosion reaction and the first product of corrosion is ferric oxide. Oxygen alone would not necessarily be detrimental were it not for this corrosion reaction. The primary function of an oxygen scavenger may therefore be to reduce ferric ions to their original state. Under such conditions, it is the iron itself that is the primary "oxygen scavenger"; the dosing agent functions primarily as a reducing agent for ferric ions.
  • Accordingly, a test procedure was used to measure the relative effectiveness of boiler corrosion inhibitors with respect to their ability to reduce ferric ions. This procedure compared the time required for equal molar concentrations of reducing agents to reduce a constant ferric concentration to a specified level. Thus, the reducing agents being tested were reacted with a ferric standard in a test call. The sensing head of a Brinkman Colorimeter Model PC/800, set at 520 nm, was placed in the cells. The drop in ferric ion concentration was continuously recorded using a Brinkman Servogor Model 210 set at 12 cm/minute. Using the data obtained, curves showing time in minutes on the ordinate versus percent absorbance on the abscissa were developed. The negative slopes of these curves are indirectly proportional to the relative effectiveness of their respective reducing agents. The most effective inhibitor evaluated was pyrogallol, which had an inverse slope of 10.0. The least effective inhibitor was sodium sulphite, which had an inverse slope of 1.2. These results are shown in Table IV, below.
    Figure imgb0001
    Figure imgb0002
    Figure imgb0003
    Figure imgb0004

Claims (6)

1. A method of inhibiting corrosion in boilers and boiler feedwater systems comprising adding to boiler feedwater containing dissolved oxygen an additive comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1.
2. A method as claimed in Claim 1, in which the amount of the additive is from 0.1 ppm to 1,000 ppm, based on the water.
3. A method as claimed in Claim 2, in which the said amount is from 1 to 100 ppm.
4. A method as claimed in any one of Claims 1 to 3, in which the trihydroxybenzene compound is pyrogallol or 1,2,4-trihydoxybenzene.
5. A corrosion-inhibiting composition comprising at least one trihydroxybenzene compound and hydroquinone in a weight ratio in the range 1:99 to 99:1.
6. A composition as claimed in Claim 5, in which the trihydroxybenzene compound is pyrogallol or 1,2,4-trihydroxybenzene.
EP86307064A 1985-09-17 1986-09-12 Method of inhibiting boiler corrosion and compositions for it Expired - Lifetime EP0215655B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86307064T ATE49424T1 (en) 1985-09-17 1986-09-12 METHOD OF INHIBITING CORROSION IN STEAM BOILERS AND COMPOSITIONS THEREOF.

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US77693585A 1985-09-17 1985-09-17
US776935 1985-09-17
US79500985A 1985-11-04 1985-11-04
US795009 1985-11-04
US80134985A 1985-11-25 1985-11-25
US801349 1985-11-25

Publications (2)

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EP0215655A1 EP0215655A1 (en) 1987-03-25
EP0215655B1 true EP0215655B1 (en) 1990-01-10

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EP86307064A Expired - Lifetime EP0215655B1 (en) 1985-09-17 1986-09-12 Method of inhibiting boiler corrosion and compositions for it

Country Status (5)

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EP (1) EP0215655B1 (en)
JP (1) JP2617453B2 (en)
AU (1) AU592367B2 (en)
CA (1) CA1294420C (en)
DE (1) DE3668190D1 (en)

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RU2557036C1 (en) * 2014-04-11 2015-07-20 Фонд поддержки научной, научно-технической и инновационной деятельности "Энергия без границ" Complex reagent for processing of steam-and-water path of power units of heat power plants

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RU2151817C1 (en) * 1997-12-03 2000-06-27 Моисеева Людмила Сергеевна Inhibitor of carbon dioxide corrosion of ferrous metals in oil and gas production and transportation systems
RU2152458C2 (en) * 1997-12-22 2000-07-10 Моисеева Людмила Сергеевна Acid corrosion-inhibiting demulsifier in oil-field media
RU2151818C1 (en) * 1998-02-11 2000-06-27 Моисеева Людмила Сергеевна Multipurpose metal corrosion inhibitor in oil and gas production and transportation systems
RU2415970C2 (en) * 2008-05-22 2011-04-10 Институт органической химии Уфимского научного центра РАН Inhibitor of carbonic-acidic corrosion of steel
RU2447198C1 (en) * 2010-09-27 2012-04-10 Государственное учреждение "Научно-исследовательский технологический институт гербицидов и регуляторов роста растений с опытно-экспериментальным производством Академии наук Республики Башкортостан" Method of inhibiting metal corrosion
RU2543591C2 (en) * 2013-07-19 2015-03-10 Открытое акционерное общество "Всероссийский дважды ордена Трудового Красного Знамени теплотехнический научно-исследовательский институт" Method of establishing water-chemical mode based on complex amine-containing reagent for water-steam circuit of power generating unit with combined-cycle gas turbines
RU2702534C1 (en) * 2017-11-16 2019-10-08 Публичное акционерное общество "Федеральная гидрогенерирующая компания - РусГидро" System for corrosion protection of geothermal power plant circuit with additional mixing
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Cited By (1)

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Publication number Priority date Publication date Assignee Title
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JP2617453B2 (en) 1997-06-04
DE3668190D1 (en) 1990-02-15
AU6273486A (en) 1987-03-19
CA1294420C (en) 1992-01-21
JPS62116788A (en) 1987-05-28
AU592367B2 (en) 1990-01-11
EP0215655A1 (en) 1987-03-25

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