Boiler Water Impurities Quiz
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Questions and Answers

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

  • Oxygen, Nitrogen, Carbon Dioxide, Sulfur Dioxide
  • Iron, Aluminum, Calcium, Chlorine
  • Suspended Solids, Dissolved Solids, Dissolved Gases, pH (correct)
  • Copper, Lead, Zinc, Chromium

What typical problem results from sludge being carried along by flowing water in a boiler system?

  • Formation of scale from salts
  • Deposition on the boiler heat transfer surfaces (correct)
  • Reduced efficiency
  • Corrosion in the hottest areas of the boiler

What is the result of salts that are insoluble under the conditions inside the boiler?

  • Carryover
  • Reduced efficiency
  • Formation of scale (correct)
  • Corrosion

What is the potential effect of carryover from impurities downstream from the boiler in a boiler system?

<p>Negative impact on the purity of the steam contacting susceptible parts of the energy plant (C)</p> Signup and view all the answers

What is the potential consequence of any impurity in a boiler system?

<p>Reduced efficiency (A)</p> Signup and view all the answers

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

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

What is the primary concern regarding the presence of oxygen and carbon dioxide in water for Power Engineers?

<p>Boiler corrosion (C)</p> Signup and view all the answers

How does the solubility of gases in water change with an increase in temperature?

<p>Decreases (A)</p> Signup and view all the answers

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

<p>To reduce the dissolved oxygen level (C)</p> Signup and view all the answers

How does carbon dioxide affect metal surfaces in condensate return lines?

<p>It causes grooving (B)</p> Signup and view all the answers

What does a high pH value in boiler water indicate?

<p>Basic or alkaline solution (B)</p> Signup and view all the answers

What is the main reason for adding sodium hydroxide (caustic soda) to boiler water?

<p>To increase pH (B)</p> Signup and view all the answers

What effect does high pH boiler water have on ferrous boiler metal?

<p>Dissolves the metal (C)</p> Signup and view all the answers

What is the primary concern related to a pH lower than 8.5 in boiler water?

<p>Increased corrosion (B)</p> Signup and view all the answers

How does acidity affect the water from lakes and rivers?

<p>No effect on acidity (A)</p> Signup and view all the answers

What is the primary purpose of using lime exchangers softeners and anion exchangers for dissolved solids removal?

<p>To reduce chloride and fluoride concentration (B)</p> Signup and view all the answers

What happens to dissolved gases like nitrogen and ammonia as the temperature increases?

<p>Their solubility decreases (B)</p> Signup and view all the answers

What is one of the major reasons for the treatment of impurities found in water supplies by external systems?

<p>To remove dissolved solids (B)</p> Signup and view all the answers

What is the main purpose of external treatment of boiler water?

<p>To treat the raw water before it enters the boiler/steam cycle (D)</p> Signup and view all the answers

What are suspended solids in boiler water mainly composed of?

<p>Insoluble substances held or suspended in the water (D)</p> Signup and view all the answers

How are Total Suspended Solids (TSS) usually determined?

<p>By running a given sample of water through a standard 2 µm filter and measuring the amount of solids filtered out (C)</p> Signup and view all the answers

What is the most common method of reducing the levels of suspended solids in boiler water?

<p>Pressure filtration (A)</p> Signup and view all the answers

What is the main problem caused by dissolved solids in boiler water?

<p>Reduction in heat transfer efficiency (D)</p> Signup and view all the answers

Which technology can be used to remove silica from boiler water?

<p>Lime softening (A)</p> Signup and view all the answers

What is the main problem caused by scale buildup in a boiler?

<p>Reduced heat transfer efficiency (B)</p> Signup and view all the answers

How can sludge and scale buildup lead to boiler overheating?

<p>By making heat transfer surfaces rough (A)</p> Signup and view all the answers

What is the primary cause of foaming in a boiler?

<p>Presence of oils in the boiler water (B)</p> Signup and view all the answers

How can foaming impact the produced steam?

<p>Make the steam drier (B)</p> Signup and view all the answers

What technology can be used to remove colloidal silica from boiler water?

<p>Reverse osmosis (A)</p> Signup and view all the answers

What is the main purpose of internal treatment within a boiler?

<p>To add specific chemicals that target problematic impurities (C)</p> Signup and view all the answers

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