Boiler Water Impurities Quiz
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Questions and Answers

What is the primary concern for Power Engineers regarding dissolved gases in water?

  • Acidic corrosion of the condensate return lines
  • Pitting and corrosion of the boiler metal (correct)
  • Formation of carbonic acid in the condensate lines
  • Rusting of the boiler metal

    • What is the purpose of using deaerators in controlling dissolved oxygen?

  • To lower the dissolved oxygen level (correct)
  • To inhibit the formation of carbonic acid
  • To reduce the pH level of the water
  • To increase the solubility of oxygen in water

    • What effect does dissolved carbon dioxide have on the pH level in a boiler?

  • It has no effect on the pH level
  • It causes neutralization of the pH level
  • It raises the pH level
  • It lowers the pH level (correct)

    • What is the relationship between pH value and acidity?

    <p>Lower pH indicates higher acidity</p> Signup and view all the answers

    How does high pH boiler water affect ferrous boiler metal?

    <p>It dissolves any existing protective oxide layer</p> Signup and view all the answers

    What is the purpose of adding sodium hydroxide (caustic soda) to boiler water?

    <p>To increase the pH level</p> Signup and view all the answers

    Why is oxygen a concern in boiler water?

    <p>It causes pitting and localized corrosion in the boiler metal</p> Signup and view all the answers

    What are the impurities or conditions most often identified as important water quality measures in a boiler system?

    <p>Suspended Solids, Dissolved Solids, Dissolved Gases, pH</p> Signup and view all the answers

    What can result from impurities in a boiler system?

    <p>Reduction in efficiency and potential catastrophic failure</p> Signup and view all the answers

    What is the typical problem that can result from carryover of impurities downstream from the boiler?

    <p>Negatively affecting the purity of the steam</p> Signup and view all the answers

    What will scale formation from salts do inside a boiler?

    <p>Cause blockages and reduce heat transfer efficiency</p> Signup and view all the answers

    Where are the typical areas of corrosion in a boiler due to impurities?

    <p>Hottest areas of the boiler such as the water wall</p> Signup and view all the answers

    What will suspended solids do if left untreated in a boiler system?

    <p>Deposit on the boiler heat transfer surfaces</p> Signup and view all the answers

    What is the general relationship between operating pressure and feedwater purity in a boiler system?

    <p>Higher operating pressure requires purer feedwater</p> Signup and view all the answers

    Where can sludge from flowing water deposit within a boiler system?

    <p>On the boiler heat transfer surfaces</p> Signup and view all the answers

    What are the two main categories of methods for treating boiler water?

    <p>External and internal treatment</p> Signup and view all the answers

    What are examples of suspended solids in the boiler water?

    <p>Clay, sand, and silica</p> Signup and view all the answers

    Which method is commonly used to reduce the levels of suspended solids in boiler water?

    <p>Gravity settling (clarifiers) and pressure filtration</p> Signup and view all the answers

    What is the most common dissolved solids of interest in boiler water?

    <p>Calcium salts of bicarbonate, sulfate, carbonate, and chloride</p> Signup and view all the answers

    What is the main problem caused by hardness in boiler water?

    <p>Boiler tube scaling</p> Signup and view all the answers

    How can colloidal silica be reduced in boiler water?

    <p>Agglomeration techniques such as used in a clarifier</p> Signup and view all the answers

    How can sludge be controlled in a boiler?

    <p>By blowing down the boiler mud drum</p> Signup and view all the answers

    What can sludge and scale buildup lead to in a boiler?

    <p>Boiler overheating</p> Signup and view all the answers

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