4AE3 U12 C5 Review
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Questions and Answers

What is the source of impurities in boilers?

  • Water treatment chemicals
  • Both make-up water and condensate returning from steam-utilizing processes (correct)
  • Only make-up water
  • Condensate returning from steam-utilizing processes

    • What happens to the impurities when water treatment chemicals are added to the boiler water?

  • They are unaffected by the chemicals
  • They are completely removed from the boiler water
  • They react with the chemicals and form new compounds that remain dissolved
  • They react with the chemicals and form new compounds that precipitate from solution (correct)

    • What can happen if impurities are left unaddressed in boilers?

  • Impurities are completely removed from the boiler water
  • Boiler efficiency increases
  • Waterside scale and corrosion occur (correct)
  • Boiler metal becomes stronger

    • What can happen when precipitates settle out in boilers?

    <p>They can bake onto heat transfer surfaces or obstruct boiler water circulation</p> Signup and view all the answers

    What can happen when impurities increase in concentration in the boiler water?

    <p>The tendency for boilers to carry-over impurities with the steam increases</p> Signup and view all the answers

    What can happen when scale-forming compounds are deposited in the superheater tubing?

    <p>Superheater overheating and failure occur</p> Signup and view all the answers

    What is the term used to describe the accumulated precipitated and suspended matter at the base of a boiler shell?

    <p>Mud</p> Signup and view all the answers

    What is the primary factor that affects the rate of precipitate formation in a boiler system?

    <p>Make-up water quality</p> Signup and view all the answers

    Why is it necessary to use high-quality make-up water in boilers with high make-up requirements?

    <p>To prevent mud and scale formation</p> Signup and view all the answers

    What is the purpose of Bottom Blowoff in a boiler system?

    <p>To remove accumulated sediment at the base of the boiler</p> Signup and view all the answers

    What is the recommended frequency of Bottom Blowoff according to ASME VII?

    <p>At least once every 24 hours</p> Signup and view all the answers

    What is the effect of flashing water when blowoff valves are opened?

    <p>Vibration and shaking in the blowoff line</p> Signup and view all the answers

    What is the purpose of designing blowoff piping for shock service?

    <p>To withstand the shock and thermal expansion of the blowoff piping</p> Signup and view all the answers

    What are the components of a Bottom Blowoff system?

    <p>Blowoff valves, blowoff piping, and blowoff vessels</p> Signup and view all the answers

    What is the primary consideration when designing blowoff valves?

    <p>Material strength and resistance to erosion</p> Signup and view all the answers

    What is the exception to the requirement for blowoff piping in boilers?

    <p>Hot water heating boilers</p> Signup and view all the answers

    What is a result of carryover in steam boilers?

    <p>Deposits of silica on turbine blading</p> Signup and view all the answers

    What is the purpose of blowdown and blowoff in steam boilers?

    <p>To prevent the accumulation of sediment and dissolved solids</p> Signup and view all the answers

    What is the main difference between blowoff and blowdown systems in heating boilers and power boilers?

    <p>Heating boilers have less robust blowoff and blowdown systems</p> Signup and view all the answers

    What is the term 'bottom blowoff' referring to?

    <p>The intermittent removal of sediment accumulated in drums, shells, and headers</p> Signup and view all the answers

    What is the ideal scenario for boiler feedwater sources?

    <p>Every kilogram of steam produced is returned to the boiler in a 100% pure state</p> Signup and view all the answers

    What is the primary source of boiler water impurity?

    <p>Make-up water</p> Signup and view all the answers

    What is the purpose of external water treatment equipment?

    <p>To convert dissolved calcium and magnesium compounds to sodium compounds</p> Signup and view all the answers

    What is the purpose of internal chemical treatment in steam boilers?

    <p>To precipitate scale-forming calcium and magnesium</p> Signup and view all the answers

    What is the result of carryover in terms of turbine efficiency?

    <p>Reduced turbine efficiency</p> Signup and view all the answers

    What is the purpose of the blowoff line in steam boilers?

    <p>To blow out sediment and impurities from the boiler under pressure</p> Signup and view all the answers

    What is the minimum number of boiler blowoff valves required by ASME B31.1?

    <p>One</p> Signup and view all the answers

    What type of valve is shown in Figure 2?

    <p>Y-Type Globe Valve</p> Signup and view all the answers

    What is the purpose of the port in the lower part of the plunger in a seatless slow-opening valve?

    <p>To allow boiler water to flow through the valve</p> Signup and view all the answers

    What is the advantage of a Y-type valve over a regular globe valve?

    <p>It has a lower pressure drop</p> Signup and view all the answers

    What is the function of the spring in a quick-opening valve?

    <p>To force the disc against the seat</p> Signup and view all the answers

    What can happen if a quick-opening valve is left leaking for a long time?

    <p>The valve seat and disc will wire draw</p> Signup and view all the answers

    What type of valve is required by ASME B31.1 to be at least one in a power boiler?

    <p>Slow-Opening Valve</p> Signup and view all the answers

    What is the characteristic of a slow-opening valve?

    <p>It requires at least five 360° turns of the operating mechanism to open or shut</p> Signup and view all the answers

    What is the purpose of the markings on a quick-opening valve?

    <p>To indicate the valve is open or shut</p> Signup and view all the answers

    What happens when the plunger hole in a seatless slow-opening valve aligns with the valve inlet?

    <p>The valve is open</p> Signup and view all the answers

    What is the primary purpose of blowoff piping?

    <p>To allow for thermal expansion and contraction</p> Signup and view all the answers

    What is the function of a blowoff vessel?

    <p>To depressurize and cool the blowoff water</p> Signup and view all the answers

    What is the minimum pressure requirement for the installation of a blowoff vessel?

    <p>103 kPa</p> Signup and view all the answers

    What is the purpose of the inlet line in a blowoff vessel?

    <p>To mix the incoming hot water with the cooler water in the tank</p> Signup and view all the answers

    What is the maximum temperature allowed for the blowoff water at the outlet of the blowoff vessel?

    <p>65°C</p> Signup and view all the answers

    What is the purpose of the anti-siphon hole in a blowoff vessel?

    <p>To prevent the vessel from draining completely</p> Signup and view all the answers

    What is the result of inadequate blowoff?

    <p>Increased sediment accumulation and adhesion to heat transfer surfaces</p> Signup and view all the answers

    What is the purpose of quenching water in some blowoff vessels?

    <p>To cool the blowoff water to a safe temperature</p> Signup and view all the answers

    What is the ASME code that specifies the materials and design of power boiler blowdown piping?

    <p>ASME B31.1</p> Signup and view all the answers

    Why is it important to anchor blowoff piping to prevent transmission of motion back to the boiler?

    <p>To prevent damage to the boiler and its components</p> Signup and view all the answers

    What is the primary reason for positioning bottom blowoff valves at the lowest parts of the boiler?

    <p>To prevent the accumulation of suspended matter at the bottom of the water space</p> Signup and view all the answers

    Why is it essential to lock out and tag boilers open for maintenance or inspection during bottom blowoff?

    <p>To prevent blowoff water from entering the open drum of another boiler</p> Signup and view all the answers

    What is the primary purpose of having an assistant watch the gauge glass during bottom blowoff?

    <p>To warn the operator if the boiler water level gets too low</p> Signup and view all the answers

    What should be done with blowoff valves after a blowoff operation is complete?

    <p>Confirm they are shut and verify the sequence</p> Signup and view all the answers

    What is the recommended practice for operating blowoff valves during bottom blowoff?

    <p>Open and close them slowly to prevent water hammer</p> Signup and view all the answers

    Why is it important to visibly number or identify boilers in a multiple boiler plant?

    <p>To prevent blowing off the wrong boiler</p> Signup and view all the answers

    What is the purpose of quenching water during bottom blowoff?

    <p>To prevent thermal shock</p> Signup and view all the answers

    Why is it recommended to perform bottom blowoff when the boiler load is low or moderate?

    <p>To minimize disruption to boiler water circulation</p> Signup and view all the answers

    What is the purpose of the valve closest to the boiler in a blowoff valve combination?

    <p>To protect the valve from erosive action</p> Signup and view all the answers

    What should be done during a bottom blowoff operation to prevent water hammer?

    <p>Open the blowoff valves slowly and in the proper sequence</p> Signup and view all the answers

    What is the purpose of a guard valve in a combination quick-opening and slow-opening valve arrangement?

    <p>To act as a shut-off valve adjacent to the boiler</p> Signup and view all the answers

    What is the recommended sequence for opening and closing valves in a combination quick-opening and slow-opening valve arrangement?

    <p>Open the guard valve first and close it last, and open the blowoff valve last and close it first</p> Signup and view all the answers

    What can happen if the correct operating sequence is not followed when using two seatless slow-opening valves?

    <p>The valve body may crack due to water compression</p> Signup and view all the answers

    What is the purpose of a surface blowoff system in a boiler?

    <p>To remove impurities from the boiler water surface</p> Signup and view all the answers

    What is the importance of using a graduated metering valve in a continuous surface blowoff system?

    <p>It allows for more precise control of the blowoff flow rate</p> Signup and view all the answers

    Why is it important to follow the correct operating sequence when using two hard-seated slow-opening valves?

    <p>To ensure one valve is the guard valve and the other is the blowing valve</p> Signup and view all the answers

    What is the purpose of the perforated pipe in a surface blowoff system?

    <p>To remove impurities from the boiler water surface</p> Signup and view all the answers

    What can happen if the blowoff valve is pumped to blow off the boiler?

    <p>Water hammer will occur</p> Signup and view all the answers

    Why is it important to ensure that the valve furthest from the boiler is opened first and closed last when using two seatless slow-opening valves?

    <p>To prevent water from becoming trapped between the valves</p> Signup and view all the answers

    What is the purpose of the isolation valve in a surface blowoff system?

    <p>To isolate the boiler from the blowoff system</p> Signup and view all the answers

    What is the primary consequence of impurities being left unaddressed in boilers?

    <p>Creation of waterside scale and corrosion</p> Signup and view all the answers

    What is the purpose of adding water treatment chemicals to the boiler water?

    <p>To react with impurities and form precipitates that can settle out</p> Signup and view all the answers

    What is the result of precipitates settling out in low water cutoff float cages and water columns?

    <p>Interference with cutoff and gauge glass operation</p> Signup and view all the answers

    Why do impurities increase in concentration in the boiler water as the boiler operates?

    <p>Because of the concentration of impurities in the feedwater</p> Signup and view all the answers

    What is the consequence of carryover in steam boilers?

    <p>Deposits of scale-forming compounds in the superheater tubing</p> Signup and view all the answers

    What is the source of impurities in boilers?

    <p>Make-up water and condensate returning from steam-utilizing processes</p> Signup and view all the answers

    What is the primary consequence of not performing blowdown and blowoff in steam boilers?

    <p>Scale formation and sediment accumulation</p> Signup and view all the answers

    Why is make-up water a primary source of boiler water impurity?

    <p>It contains varying amounts of suspended matter, dissolved solids, and dissolved gases</p> Signup and view all the answers

    What is the purpose of adding chemicals to boiler water?

    <p>To precipitate scale-forming calcium and magnesium</p> Signup and view all the answers

    What can happen if impurities are not removed from the boiler water?

    <p>Scale formation and sediment accumulation will occur</p> Signup and view all the answers

    What is the difference between surface blowoff and bottom blowoff?

    <p>Surface blowoff removes sediment, while bottom blowoff removes dissolved solids</p> Signup and view all the answers

    Why is it important to ensure that the blowdown system is operated correctly?

    <p>To prevent the accumulation of sediment and dissolved solids</p> Signup and view all the answers

    What is the result of not treating make-up water before adding it to the boiler?

    <p>Impurities will enter the boiler and cause problems</p> Signup and view all the answers

    What is the purpose of external water treatment equipment?

    <p>To convert calcium and magnesium compounds to sodium compounds</p> Signup and view all the answers

    What is the cause of carryover in steam boilers?

    <p>All of the above</p> Signup and view all the answers

    What is the result of carryover in terms of turbine efficiency?

    <p>Decreased efficiency</p> Signup and view all the answers

    What is the primary factor that affects the rate of precipitate formation in a boiler system with high steam production?

    <p>Quality of make-up water</p> Signup and view all the answers

    Why is it necessary to design blowoff piping for shock service?

    <p>To prevent all of the above</p> Signup and view all the answers

    What is the characteristic of a blowoff valve that is specially designed for severe service?

    <p>It is made of materials that are strong at high pressures and temperatures</p> Signup and view all the answers

    What is the minimum design pressure of the blowoff piping system components that exceeds the MAWP of the boiler?

    <p>It is specified in ASME B31.1</p> Signup and view all the answers

    What is the purpose of the anti-siphon hole in a blowoff vessel?

    <p>To prevent the formation of a vacuum in the vessel</p> Signup and view all the answers

    What is the result of inadequate blowoff in a boiler system?

    <p>The formation of mud and scale in the boiler</p> Signup and view all the answers

    What is the primary purpose of the frequency and duration of blowoff in a boiler system?

    <p>To remove accumulated sediment at the base of the boiler</p> Signup and view all the answers

    What is the effect of flashing water when blowoff valves are opened?

    <p>A sudden temperature rise and the formation of steam</p> Signup and view all the answers

    What is the purpose of the rules for blowoff valves and blowoff piping in ASME B31.1 and ASME IV?

    <p>To ensure the safe operation of the boiler</p> Signup and view all the answers

    What is the characteristic of a boiler system that requires high-quality make-up water?

    <p>It has a high make-up water requirement</p> Signup and view all the answers

    What is the primary consideration for selecting the construction material of blowoff valves in power boilers?

    <p>Boiler pressure and temperature</p> Signup and view all the answers

    What is the purpose of the stem angle in a Y-type globe valve?

    <p>To reduce the pressure drop across the valve</p> Signup and view all the answers

    What is the primary characteristic of a slow-opening valve?

    <p>It requires multiple 360° turns of the operating mechanism to change from fully closed to fully open</p> Signup and view all the answers

    What is the function of the port in the lower part of the plunger in a seatless slow-opening valve?

    <p>To facilitate the flow of boiler water through the valve</p> Signup and view all the answers

    Why is it important to ensure that the valve does not leak for a long time in a quick-opening valve?

    <p>To prevent the valve seat and disc from wire drawing</p> Signup and view all the answers

    What is the purpose of the markings on the body of a quick-opening valve?

    <p>To enable the operator to determine the valve's position</p> Signup and view all the answers

    What is the advantage of using a Y-type valve over a regular globe valve?

    <p>It reduces the pressure drop across the valve and enables sediment and water to freely discharge</p> Signup and view all the answers

    What is the purpose of the spring in a quick-opening valve?

    <p>To provide a tight seal between the valve disc and seat</p> Signup and view all the answers

    What is the primary advantage of using a hard-seated valve over a seatless valve?

    <p>It is more durable and resistant to wear and tear</p> Signup and view all the answers

    What is the purpose of the welded bonnet in a Y-type valve?

    <p>To enhance the valve's structural integrity and prevent leakage</p> Signup and view all the answers

    What is the primary reason why waterwall header blowoff is never performed when large steam generating units are in operation?

    <p>To prevent loss of water circulation and exposure to overheating</p> Signup and view all the answers

    What is the purpose of quenching water in some blowoff vessels?

    <p>To prevent thermal shock</p> Signup and view all the answers

    Why is it important to ensure that any boilers open for maintenance or inspection are properly locked out and tagged during bottom blowoff?

    <p>To prevent blowoff water from entering the open drum of another boiler</p> Signup and view all the answers

    What is the recommended practice when operating blowoff valves during bottom blowoff?

    <p>Open the valves slowly and in the proper sequence</p> Signup and view all the answers

    What is the purpose of the valve closest to the boiler in a blowoff valve combination?

    <p>To protect the valve from the erosive action of the boiler water</p> Signup and view all the answers

    What is the primary consideration when designing blowoff valves?

    <p>Preventing erosion of the valve</p> Signup and view all the answers

    What can happen if the blowoff valves are not operated slowly and in the proper sequence during bottom blowoff?

    <p>Water hammer may occur</p> Signup and view all the answers

    Why is it important to verify that quenching water is on before beginning the blowoff procedure?

    <p>To prevent thermal shock</p> Signup and view all the answers

    What is the purpose of having an assistant watch the gauge glass during bottom blowoff?

    <p>To warn the operator if the boiler water level gets too low</p> Signup and view all the answers

    What is the primary purpose of performing bottom blowoff?

    <p>To remove suspended matter and sediment from the boiler</p> Signup and view all the answers

    What is the main purpose of the blowoff vessel in a boiler system?

    <p>To depressurize the blowoff water and cool it to a suitable temperature for the sewer system</p> Signup and view all the answers

    According to the CSA B51 Code, what is the maximum temperature allowed for the blowoff water at the outlet of the blowoff vessel?

    <p>65°C</p> Signup and view all the answers

    What is the primary purpose of the anchor in the blowoff piping system?

    <p>To prevent the transmission of motion from the piping to the boiler</p> Signup and view all the answers

    What is the result of inadequate blowoff in a boiler system?

    <p>Sediment accumulation and adherence to heat transfer surfaces and other boiler parts</p> Signup and view all the answers

    What is the primary function of the anti-siphon hole in a blowoff vessel?

    <p>To prevent the vessel from draining completely</p> Signup and view all the answers

    What is the primary reason for using a slow-opening valve in a blowoff system?

    <p>To prevent water hammer</p> Signup and view all the answers

    What is the purpose of the inlet line in a blowoff vessel?

    <p>To mix the incoming hot water with the cooler water in the vessel</p> Signup and view all the answers

    What is the requirement for the installation of a blowoff vessel according to the CSA B51 Code?

    <p>For all boilers operating above 103 kPa gauge</p> Signup and view all the answers

    What is the purpose of the valve closest to the boiler in a combination quick-opening and slow-opening valve arrangement?

    <p>To act as a guard valve</p> Signup and view all the answers

    Why is it important to follow the correct operating sequence when using two seatless slow-opening valves?

    <p>To prevent valve damage</p> Signup and view all the answers

    What is the purpose of the inspection and cleaning access in a blowoff vessel?

    <p>To facilitate the inspection and cleaning of the vessel</p> Signup and view all the answers

    What is the purpose of a surface blowoff system in a boiler?

    <p>To remove impurities from the boiler water surface</p> Signup and view all the answers

    What is the effect of excessive blowoff in a boiler system?

    <p>Discharge of treated water, internal treatment chemicals, and heat from the boiler</p> Signup and view all the answers

    What is the purpose of the ASME B31.1 Power Piping Code in relation to blowoff piping?

    <p>To specify the materials and design of power boiler blowdown piping</p> Signup and view all the answers

    What can happen if the correct operating sequence is not followed when using two hard-seated slow-opening valves?

    <p>The valve may be damaged</p> Signup and view all the answers

    Why is it important to ensure that the valve furthest from the boiler is opened first and closed last when using two seatless slow-opening valves?

    <p>To prevent valve damage</p> Signup and view all the answers

    What is the characteristic of a slow-opening valve in a blowoff system?

    <p>It opens slowly to reduce the possibility of water hammer</p> Signup and view all the answers

    What is the purpose of an isolation valve in a surface blowoff system?

    <p>To isolate the surface blowoff system from the boiler</p> Signup and view all the answers

    What can happen if the blowoff valve is pumped to blow off the boiler?

    <p>Water hammer may occur</p> Signup and view all the answers

    What is the purpose of a guard valve in a combination quick-opening and slow-opening valve arrangement?

    <p>To ensure a leak-tight shut-off adjacent to the boiler</p> Signup and view all the answers

    What is the primary reason for controlling the concentration of dissolved solids in boiler water?

    <p>To prevent carryover and impede heat transfer</p> Signup and view all the answers

    What are the examples of dissolved solids in boiler water?

    <p>Various sodium compounds, such as carbonates, bicarbonates, chlorides, and phosphates</p> Signup and view all the answers

    What is the effect of high concentrations of dissolved solids in boiler water?

    <p>It can lead to carryover and impede heat transfer</p> Signup and view all the answers

    How do dissolved solids enter the boiler water?

    <p>They enter the boiler with the make-up water, or return with the condensate</p> Signup and view all the answers

    What is the purpose of continuous blowdown in boiler operation?

    <p>To control the concentration of dissolved solids in boiler water</p> Signup and view all the answers

    What can happen if the concentration of dissolved solids is not controlled in boiler water?

    <p>It can lead to foaming and priming</p> Signup and view all the answers

    What is the primary purpose of continuous blowdown in a boiler?

    <p>To control the concentration of dissolved solids in the boiler water</p> Signup and view all the answers

    What is the main factor that determines the quality of feedwater required for a boiler?

    <p>Boiler operating pressure</p> Signup and view all the answers

    What is the purpose of filtering and softening returns with condensate polishing equipment?

    <p>To remove suspended matter from the returns</p> Signup and view all the answers

    What is the term used to describe the measurement of dissolved solids concentration in boiler water?

    <p>Specific conductance</p> Signup and view all the answers

    What is the primary function of the internal continuous blowdown collection pipe in the steam drum?

    <p>To collect boiler water with the highest dissolved solids concentration</p> Signup and view all the answers

    What is the purpose of measuring the solids concentration of the boiler water during continuous blowdown?

    <p>To adjust the metering valve to maintain the prescribed solids concentration</p> Signup and view all the answers

    What is the purpose of the CBD valve in a blowdown system?

    <p>To control the flow of blowdown water to the blowoff vessel</p> Signup and view all the answers

    What is the result of not controlling the concentration of dissolved solids in the boiler water?

    <p>Scale formation and potential boiler damage</p> Signup and view all the answers

    What is the recommended practice for determining the blowdown rate?

    <p>Conducting regular water tests at the beginning of every shift</p> Signup and view all the answers

    Why is it important to adjust the CBD valve carefully?

    <p>To prevent excessive blowdown and waste of treated water</p> Signup and view all the answers

    What is the purpose of ASME B31.1 code in relation to blowdown systems?

    <p>To specify the materials and design of power boiler blowdown piping</p> Signup and view all the answers

    What is the recommended material for blowdown piping in boilers operating at pressures higher than 690 kPa?

    <p>Steel, at least Schedule 80</p> Signup and view all the answers

    What is the primary purpose of installing a heat recovery system in a blowdown system?

    <p>To conserve heat energy and reduce energy losses</p> Signup and view all the answers

    What is the effect of high-pressure boilers on the need for feedwater quality?

    <p>Increased need for high-quality feedwater</p> Signup and view all the answers

    What is the purpose of ultra-pure make-up water in high-pressure boilers?

    <p>To reduce the need for internal boiler water treatment chemicals</p> Signup and view all the answers

    What is the effect of excessive continuous blowdown on a boiler system?

    <p>It wastes treated water, chemicals, and heat</p> Signup and view all the answers

    What is the purpose of the vernier scale on a CBD valve?

    <p>To indicate the valve position and facilitate fine flow control</p> Signup and view all the answers

    What factor determines the design pressure of the blowdown piping system?

    <p>The boiler's MAWP</p> Signup and view all the answers

    What is the primary reason for installing a single shut-off valve in the CBD line?

    <p>To isolate the boiler from the blowdown system</p> Signup and view all the answers

    What is the purpose of adjusting the flow of blowdown water in a boiler system?

    <p>To regulate the TDS concentration in the boiler water</p> Signup and view all the answers

    What is the primary benefit of using an automated continuous blowdown system?

    <p>Reducing the total amount of blowdown and fuel costs</p> Signup and view all the answers

    What is the purpose of the heat exchanger in a blowdown heat recovery system?

    <p>To recover heat from the blowdown water and preheat the make-up water</p> Signup and view all the answers

    Why is it important to regularly inspect the blowoff system?

    <p>To prevent thermal shock and wear and tear on components</p> Signup and view all the answers

    What is the recommended material for blowoff piping operating above 690 kPa?

    <p>Schedule 80 steel</p> Signup and view all the answers

    What is the purpose of the 45° elbow in blowoff piping?

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

    What should be done if a valve is found damaged during inspection?

    <p>Replace it with the exact same valve</p> Signup and view all the answers

    What is the benefit of increasing the temperature of the feedwater by 5°C?

    <p>A 1% increase in efficiency</p> Signup and view all the answers

    What is the purpose of the solenoid valve in an automated continuous blowdown system?

    <p>To shut off the blowdown flow when the boiler is off</p> Signup and view all the answers

    What is the consequence of not repairing or replacing damaged blowoff system components?

    <p>Increased risk of explosion and damage to the system</p> Signup and view all the answers

    What should be inspected during regular blowoff system inspection?

    <p>The boiler blowoff vessel, blowoff valves, and blowoff piping</p> Signup and view all the answers

    What is the primary reason why dissolved solids in boiler water can lead to superheater failure?

    <p>The dissolved solids concentrate in the boiler water, carrying over with the wet steam and potentially depositing in the superheater banks, impeding heat transfer.</p> Signup and view all the answers

    What is the primary source of impurities in boiler water?

    <p>All of the above are potential sources of impurities in boiler water.</p> Signup and view all the answers

    What is the effect of high concentrations of dissolved solids in boiler water?

    <p>They can lead to carryover, foaming, and priming, reducing the overall efficiency of the boiler.</p> Signup and view all the answers

    What is the purpose of controlling the concentration of dissolved solids in boiler water?

    <p>To prevent carryover, foaming, and priming, and to reduce the risk of superheater failure.</p> Signup and view all the answers

    What is the primary function of chelants in boiler water treatment?

    <p>To react with impurities and form precipitates that can be removed from the boiler.</p> Signup and view all the answers

    What is the result of inadequate control of dissolved solids in boiler water?

    <p>Increased risk of superheater failure, carryover, foaming, and priming, and reduced overall efficiency of the boiler.</p> Signup and view all the answers

    What is the primary purpose of ultra-pure make-up water in high-pressure boilers?

    <p>To reduce the need for internal boiler water treatment chemicals</p> Signup and view all the answers

    What is the primary characteristic of a boiler system that requires high-quality make-up water?

    <p>High-pressure boilers</p> Signup and view all the answers

    What is the consequence of not performing continuous blowdown in steam boilers?

    <p>Scale formation</p> Signup and view all the answers

    What is the primary factor that determines the blowdown rate in a boiler system?

    <p>Rate of steam production</p> Signup and view all the answers

    What is the purpose of continuous blowdown in boiler operation?

    <p>To reduce the concentration of dissolved solids in the boiler water</p> Signup and view all the answers

    What is the primary source of impurities in boilers?

    <p>Make-up water</p> Signup and view all the answers

    What is the relationship between the electrical conductivity of water and its dissolved impurities?

    <p>The conductivity of water increases with increasing impurities</p> Signup and view all the answers

    What is the primary purpose of measuring the solids concentration of the boiler water?

    <p>To determine the blowdown rate</p> Signup and view all the answers

    What is the term used to describe the total dissolved solids (TDS) concentration in boiler water?

    <p>Specific conductance</p> Signup and view all the answers

    What is the primary reason for using continuous blowdown in high-pressure boilers?

    <p>To reduce the need for internal boiler water treatment chemicals</p> Signup and view all the answers

    What is the primary benefit of implementing an automated continuous blowdown system?

    <p>Reducing total blowdown and eliminating TDS swings</p> Signup and view all the answers

    What is the primary purpose of inspecting blowoff system components?

    <p>To identify potential safety hazards and preventive maintenance</p> Signup and view all the answers

    What is the recommended material for blowoff piping in boilers operating above 690 kPa?

    <p>Schedule 80 steel</p> Signup and view all the answers

    What is the consequence of not performing regular blowoff system inspections and maintenance?

    <p>Thermal shock and component failure</p> Signup and view all the answers

    What is the benefit of using a heat recovery system in a blowdown system?

    <p>Improving boiler efficiency by preheating feedwater</p> Signup and view all the answers

    What is the purpose of the solenoid valve in an automated continuous blowdown system?

    <p>To shut off the blowdown flow when the boiler is off</p> Signup and view all the answers

    What is the recommended procedure for repairing or replacing blowoff system components?

    <p>Following guidelines and using certified materials and welders</p> Signup and view all the answers

    What is the primary consideration when selecting blowoff valve materials?

    <p>Material strength and corrosion resistance</p> Signup and view all the answers

    What is the consequence of using inadequate or corroded blowoff piping components?

    <p>Component failure and explosion risk</p> Signup and view all the answers

    What is the purpose of the heat exchanger in a blowdown heat recovery system?

    <p>To heat the make-up water</p> Signup and view all the answers

    At what location is the internal continuous blowdown collection pipe installed in the steam drum or boiler shell?

    <p>About 15 cm below the normal operating water level</p> Signup and view all the answers

    What is the primary purpose of controlling the TDS concentration in boiler water through continuous blowdown?

    <p>To prevent excessive carryover</p> Signup and view all the answers

    What is the requirement for blowdown piping material in boilers operating at pressures higher than 690 kPa?

    <p>It must be steel, and at least Schedule 80</p> Signup and view all the answers

    What is the purpose of the vernier scale on a CBD valve?

    <p>To indicate the valve's opening position</p> Signup and view all the answers

    Why is it necessary to carefully monitor and control manual continuous blowdown?

    <p>To prevent excessive blowdown waste</p> Signup and view all the answers

    What is the typical percentage of the overall boiler steam flow rate for the CBD flow?

    <p>1% or more</p> Signup and view all the answers

    What is the purpose of the CBD valve in a blowdown system?

    <p>To control the flow of blowdown water</p> Signup and view all the answers

    What is the consequence of not opening the CBD valve sufficiently?

    <p>The TDS concentration will be too high</p> Signup and view all the answers

    Why is it important to consider the rate of steam production and type of impurities in the make-up water when designing a blowdown system?

    <p>To determine the required blowdown rate</p> Signup and view all the answers

    What is the advantage of using a V-notch plug valve in a blowdown system?

    <p>It provides more desirable flow characteristics</p> Signup and view all the answers

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