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EASY What is the current trend in cleaning large boilers?

  • Mechanical cleaning
  • Hydraulic cleaning
  • Chemical cleaning (correct)
  • Thermal cleaning

    • What is the purpose of an alkaline boil out?

  • To clean piping systems
  • To clean superheaters
  • To remove oily substances from boiler water (correct)
  • To remove scale deposits

    • What chemicals are commonly used in an alkaline boil out?

  • Sodium nitrite, sodium sulfite, and starch
  • Hydrochloric acid, sulfuric acid, and nitric acid
  • Caustic soda, soda ash, and sodium phosphate (correct)
  • Arsenic, barium compounds, and silica

    • What is the purpose of an inhibitor in acid cleaning?

    <p>To prevent or minimize metal attack</p> Signup and view all the answers

    What is a precaution when using strong alkaline cleaning solvents?

    <p>Avoid using them with non-drainable superheaters</p> Signup and view all the answers

    What is a consideration when using an acid cleaning method?

    <p>Follow proper technique and safety procedures</p> Signup and view all the answers

    What is a step in the process of acid cleaning?

    <p>Analyze the deposit to determine the right type of acid to use</p> Signup and view all the answers

    Why is chemical cleaning not always suitable for smaller boilers?

    <p>It requires complex piping and pumping systems</p> Signup and view all the answers

    What is the purpose of isolating the boiler from the steam header during acid cleaning?

    <p>To prevent acid from entering the steam header</p> Signup and view all the answers

    Why is it necessary to vent the boiler during acid cleaning?

    <p>To prevent the explosion of hydrogen gas</p> Signup and view all the answers

    What is the primary purpose of using a 5% solution of inhibited hydrochloric acid for boiler cleaning?

    <p>To effectively remove scale from the boiler</p> Signup and view all the answers

    What is the advantage of using sulfamic acid over hydrochloric acid?

    <p>It is easier to handle and less corrosive</p> Signup and view all the answers

    What is the benefit of using chelating agents for boiler cleaning?

    <p>They are less dangerous to use and remove scale slowly</p> Signup and view all the answers

    Why is it necessary to remove brass and bronze parts during acid cleaning?

    <p>To prevent corrosion of these parts</p> Signup and view all the answers

    What is the purpose of boiling out the boiler with an alkaline solution after acid cleaning?

    <p>To remove any remaining acid</p> Signup and view all the answers

    What is the benefit of using chelating agents for online cleaning of boilers?

    <p>It can remove existing scale without removing the boiler from service</p> Signup and view all the answers

    Why is it necessary to use demineralized water for flushing the boiler after acid cleaning?

    <p>To remove any remaining acid from the boiler</p> Signup and view all the answers

    What is the consequence of overfeeding chelant in boiler cleaning?

    <p>It can lead to corrosion of the boiler metal</p> Signup and view all the answers

    MEDIUM What is the primary purpose of using an alkaline boil out in boiler cleaning?

    <p>To dissolve oil and grease from the waterside of new boilers</p> Signup and view all the answers

    What precaution should be taken when using strong alkaline cleaning solvents?

    <p>Avoid using them if the boiler has non-drainable superheaters made of austenitic stainless steel</p> Signup and view all the answers

    What is the purpose of adding an inhibitor to the acid in acid cleaning?

    <p>To prevent or minimize the attack of the acid on the metal</p> Signup and view all the answers

    Why is chemical cleaning not always suitable for smaller boilers?

    <p>Because it requires complex piping and pumping systems</p> Signup and view all the answers

    What is the first step in using an acid cleaning method?

    <p>Analyze the deposit to determine the type of acid to use</p> Signup and view all the answers

    What is the purpose of following proper technique when using an acid cleaning method?

    <p>To ensure safe work procedures are in place</p> Signup and view all the answers

    Why is it advisable to perform acid cleaning under the direction of experienced personnel?

    <p>To ensure safe work procedures are in place</p> Signup and view all the answers

    What is the purpose of using a combination of caustic soda, soda ash, and sodium phosphate in alkaline boil out?

    <p>To dissolve oil and grease from the waterside of new boilers</p> Signup and view all the answers

    What is the primary purpose of isolating the boiler from the rest of the system during acid cleaning?

    <p>To prevent the acid from entering other parts of the system</p> Signup and view all the answers

    What is the advantage of using chelating agents for boiler cleaning?

    <p>They can be used to clean boilers online</p> Signup and view all the answers

    Why is it necessary to vent the boiler during acid cleaning?

    <p>To reduce the risk of explosion</p> Signup and view all the answers

    What is the purpose of using an inhibitor in acid cleaning?

    <p>To reduce the corrosiveness of the acid</p> Signup and view all the answers

    What is the benefit of using sulfamic acid over hydrochloric acid?

    <p>It is less corrosive and easier to handle</p> Signup and view all the answers

    What is the purpose of boiling out the boiler with an alkaline solution after acid cleaning?

    <p>To neutralize any remaining acid in the boiler</p> Signup and view all the answers

    Why is it necessary to remove brass and bronze parts during acid cleaning?

    <p>Because they are affected by the acid</p> Signup and view all the answers

    What is the consequence of overfeeding chelant in boiler cleaning?

    <p>It can cause the boiler metal to corrode</p> Signup and view all the answers

    What is the benefit of using demineralized water for flushing the boiler after acid cleaning?

    <p>It does not contain minerals that can deposit on the boiler</p> Signup and view all the answers

    Why is chemical cleaning not always suitable for smaller boilers?

    <p>Because they have a smaller capacity for acid</p> Signup and view all the answers

    HARD What is the primary reason for not using strong alkaline cleaning solvents in boilers with non-drainable superheaters made of austenitic stainless steel?

    <p>Because they attack austenitic stainless steels</p> Signup and view all the answers

    What is the primary benefit of using an inhibitor in acid cleaning?

    <p>It reduces the risk of acid attacking the metal</p> Signup and view all the answers

    What is the primary purpose of analyzing the deposit before using an acid cleaning method?

    <p>To determine the best type of acid to use</p> Signup and view all the answers

    What is the primary reason for using complex piping and pumping systems in chemical cleaning of large boilers?

    <p>To ensure that the chemicals are properly distributed</p> Signup and view all the answers

    What is the primary advantage of using alkaline boil out in cleaning boilers?

    <p>It is gentler on the metal surfaces</p> Signup and view all the answers

    What is the primary reason for performing acid cleaning under the direction of experienced personnel?

    <p>To ensure that the cleaning process is safe and effective</p> Signup and view all the answers

    What is the primary purpose of using a combination of caustic soda, soda ash, and sodium phosphate in alkaline boil out?

    <p>To ensure that the chemicals are effective at removing contaminants</p> Signup and view all the answers

    What is the primary reason for not using chemical cleaning for smaller boilers?

    <p>Because the cost of the equipment is not justified by the size of the boiler</p> Signup and view all the answers

    What is the primary purpose of isolating the boiler from the steam header during acid cleaning?

    <p>To prevent the acid from flowing back into the steam header</p> Signup and view all the answers

    What is the primary advantage of using chelating agents over acid cleaning methods?

    <p>They can be used to remove existing scale from a boiler without removing the boiler from service</p> Signup and view all the answers

    What is the primary purpose of using an alkaline boil out after acid cleaning?

    <p>To neutralize any remaining acid in the boiler</p> Signup and view all the answers

    What is the primary consideration when using an acid cleaning method?

    <p>The potential corrosive effects of the acid on the boiler materials</p> Signup and view all the answers

    What is the primary purpose of using sulfamic acid over hydrochloric acid?

    <p>It is less corrosive and does not produce noxious fumes</p> Signup and view all the answers

    What is the primary consequence of overfeeding chelant in boiler cleaning?

    <p>The boiler metal becomes more susceptible to corrosion</p> Signup and view all the answers

    What is the primary purpose of using demineralized water for flushing the boiler after acid cleaning?

    <p>To prevent corrosion of the boiler materials</p> Signup and view all the answers

    What is the primary reason why chemical cleaning is not always suitable for smaller boilers?

    <p>The process of acid cleaning is too complex for smaller boilers</p> Signup and view all the answers

    What is the primary purpose of venting the boiler during acid cleaning?

    <p>To prevent the buildup of hydrogen gas</p> Signup and view all the answers

    What is the primary advantage of using a combination of caustic soda, soda ash, and sodium phosphate in alkaline boil out?

    <p>It provides a more thorough cleaning of the boiler than using a single alkaline solution</p> Signup and view all the answers

    Study Notes

    Chemical Cleaning Methods for Boilers

    • Chemical cleaning is the trend for large boilers, requiring the services of a chemical company or consultant and involving complex piping and pumping systems.
    • Chemical cleaning is not economically viable for smaller boilers.

    Alkaline Boil Out Method

    • Alkaline boil out is a method of chemical cleaning that removes oil, grease, and other contaminants from the waterside of new boilers or boilers contaminated during operation.
    • The method uses a combination of caustic soda, soda ash, sodium phosphate, and sometimes sodium nitrite and sodium sulfite.
    • The chemicals are added to the boiler water, and steam pressure is raised and maintained for approximately 48 hours to dissolve deposits on drum and tube surfaces.
    • Strong alkaline solutions should not be used on boilers with non-drainable superheaters made of austenitic stainless steel.

    Inhibited Acid Cleaning Method

    • Inhibited acid cleaning uses an acid to dissolve scale and an inhibitor to prevent metal corrosion.
    • The acid and inhibitor are added to the boiler, and the boiler is isolated from the steam header and other parts.
    • The acid solution is circulated through the boiler at a temperature of about 65°C until cleaning is complete.
    • The boiler is then drained, flushed, and boiled out with an alkaline solution to neutralize any remaining acid.

    Safety Precautions for Acid Cleaning

    • The right type of acid must be used, and the deposit must be analyzed first.
    • Adequate piping systems, temperature control, and circulation must be installed.
    • The boiler must be isolated, and all parts not being cleaned must be isolated or protected.
    • Brass and bronze parts must be removed or replaced with steel parts.
    • All valves exposed to the acid must be made of steel, and all gauges and meters must be isolated.

    Safety and Environmental Considerations

    • The boiler room must be adequately ventilated, and personnel handling acids must wear proper safety clothing.
    • Spent solvent must be disposed of safely and in accordance with environmental regulations.
    • Hydrogen production and fire/explosion risks must be mitigated.

    Chelating Agents for Chemical Cleaning

    • Chelating agents can be used for chemical cleaning while the boiler remains in operation.
    • Chelating agents are less dangerous to use but more expensive than acids.
    • Chelating agents can remove existing scale from a boiler without taking it out of service.
    • However, chelant overfeeding can lead to corrosion and scale removal too quickly, causing sludge accumulation.
    • Complete oxygen removal is mandatory, and chelant feed systems must be designed with non-corrosive materials.

    Chemical Cleaning Methods for Boilers

    • Chemical cleaning is the trend for large boilers, requiring the services of a chemical company or consultant and involving complex piping and pumping systems.
    • Chemical cleaning is not economically viable for smaller boilers.

    Alkaline Boil Out Method

    • Alkaline boil out is a method of chemical cleaning that removes oil, grease, and other contaminants from the waterside of new boilers or boilers contaminated during operation.
    • The method uses a combination of caustic soda, soda ash, sodium phosphate, and sometimes sodium nitrite and sodium sulfite.
    • The chemicals are added to the boiler water, and steam pressure is raised and maintained for approximately 48 hours to dissolve deposits on drum and tube surfaces.
    • Strong alkaline solutions should not be used on boilers with non-drainable superheaters made of austenitic stainless steel.

    Inhibited Acid Cleaning Method

    • Inhibited acid cleaning uses an acid to dissolve scale and an inhibitor to prevent metal corrosion.
    • The acid and inhibitor are added to the boiler, and the boiler is isolated from the steam header and other parts.
    • The acid solution is circulated through the boiler at a temperature of about 65°C until cleaning is complete.
    • The boiler is then drained, flushed, and boiled out with an alkaline solution to neutralize any remaining acid.

    Safety Precautions for Acid Cleaning

    • The right type of acid must be used, and the deposit must be analyzed first.
    • Adequate piping systems, temperature control, and circulation must be installed.
    • The boiler must be isolated, and all parts not being cleaned must be isolated or protected.
    • Brass and bronze parts must be removed or replaced with steel parts.
    • All valves exposed to the acid must be made of steel, and all gauges and meters must be isolated.

    Safety and Environmental Considerations

    • The boiler room must be adequately ventilated, and personnel handling acids must wear proper safety clothing.
    • Spent solvent must be disposed of safely and in accordance with environmental regulations.
    • Hydrogen production and fire/explosion risks must be mitigated.

    Chelating Agents for Chemical Cleaning

    • Chelating agents can be used for chemical cleaning while the boiler remains in operation.
    • Chelating agents are less dangerous to use but more expensive than acids.
    • Chelating agents can remove existing scale from a boiler without taking it out of service.
    • However, chelant overfeeding can lead to corrosion and scale removal too quickly, causing sludge accumulation.
    • Complete oxygen removal is mandatory, and chelant feed systems must be designed with non-corrosive materials.

    Chemical Cleaning Methods for Boilers

    • Chemical cleaning is the trend for large boilers, requiring the services of a chemical company or consultant and involving complex piping and pumping systems.
    • Chemical cleaning is not economically viable for smaller boilers.

    Alkaline Boil Out Method

    • Alkaline boil out is a method of chemical cleaning that removes oil, grease, and other contaminants from the waterside of new boilers or boilers contaminated during operation.
    • The method uses a combination of caustic soda, soda ash, sodium phosphate, and sometimes sodium nitrite and sodium sulfite.
    • The chemicals are added to the boiler water, and steam pressure is raised and maintained for approximately 48 hours to dissolve deposits on drum and tube surfaces.
    • Strong alkaline solutions should not be used on boilers with non-drainable superheaters made of austenitic stainless steel.

    Inhibited Acid Cleaning Method

    • Inhibited acid cleaning uses an acid to dissolve scale and an inhibitor to prevent metal corrosion.
    • The acid and inhibitor are added to the boiler, and the boiler is isolated from the steam header and other parts.
    • The acid solution is circulated through the boiler at a temperature of about 65°C until cleaning is complete.
    • The boiler is then drained, flushed, and boiled out with an alkaline solution to neutralize any remaining acid.

    Safety Precautions for Acid Cleaning

    • The right type of acid must be used, and the deposit must be analyzed first.
    • Adequate piping systems, temperature control, and circulation must be installed.
    • The boiler must be isolated, and all parts not being cleaned must be isolated or protected.
    • Brass and bronze parts must be removed or replaced with steel parts.
    • All valves exposed to the acid must be made of steel, and all gauges and meters must be isolated.

    Safety and Environmental Considerations

    • The boiler room must be adequately ventilated, and personnel handling acids must wear proper safety clothing.
    • Spent solvent must be disposed of safely and in accordance with environmental regulations.
    • Hydrogen production and fire/explosion risks must be mitigated.

    Chelating Agents for Chemical Cleaning

    • Chelating agents can be used for chemical cleaning while the boiler remains in operation.
    • Chelating agents are less dangerous to use but more expensive than acids.
    • Chelating agents can remove existing scale from a boiler without taking it out of service.
    • However, chelant overfeeding can lead to corrosion and scale removal too quickly, causing sludge accumulation.
    • Complete oxygen removal is mandatory, and chelant feed systems must be designed with non-corrosive materials.

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    Description

    This quiz covers the methods and techniques used for chemical cleaning of boilers, including the alkaline boil out method and its applications.

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