3B2 E2.5 C12 Review
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Questions and Answers

What does the term 'hairpin exchanger' refer to?

  • An arrangement of double pipe exchangers resembling a hairpin or multiple hairpins connected together (correct)
  • A type of tubular exchanger with helicoidal fins
  • A type of longitudinal fins used in heat exchangers
  • An arrangement of fin tube exchangers resembling a hairpin shape

    • What is a key advantage of double pipe exchangers mentioned in the text?

  • Inflexibility in design
  • Complex maintenance process
  • Ability to add or remove units to meet design heat transfer needs (correct)
  • Suitability only for low-pressure applications

    • In what configuration can double pipe exchangers be connected for fluid flow?

  • Co-current or counter-flow (correct)
  • Co-current flow only
  • Counter-flow only
  • Parallel flow

    • What do the hairpin exchangers provide due to the longer flow path for both inner and outer flows?

    <p>Greater overall heat transfer between the two fluids</p> Signup and view all the answers

    What is a disadvantage of double pipe exchangers mentioned in the text?

    <p>High number of joints leading to increased risk of leaks</p> Signup and view all the answers

    Which factor allows for simple maintenance and replacement of sections in double pipe exchangers?

    <p>Flexibility of configuration</p> Signup and view all the answers

    What is the basic principle of a double-pipe heat exchanger?

    <p>Heat is exchanged from one fluid to the outer surface of the pipe, through the pipe wall, and then to the second fluid.</p> Signup and view all the answers

    What is the term used to describe the arrangement in Figure 1?

    <p>Concentric pipe heat exchanger</p> Signup and view all the answers

    What is the purpose of fins or studs attached to the inner pipe?

    <p>To increase the heat transfer surface</p> Signup and view all the answers

    What is the flow arrangement in Figure 1?

    <p>Counter-current</p> Signup and view all the answers

    What is an example of a double-pipe heat exchanger in use?

    <p>A steam-jacketed line</p> Signup and view all the answers

    What is the term used to describe the space between the inner and outer pipes?

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

    How does the arrangement of double pipe exchangers in a hairpin configuration affect heat transfer?

    <p>Increases the retention time leading to greater overall heat transfer</p> Signup and view all the answers

    What is a significant differentiator of hairpin exchangers in comparison to other designs?

    <p>They allow for addition and removal of units to meet design requirements</p> Signup and view all the answers

    What feature of double pipe exchangers contributes to their suitability for high-pressure applications?

    <p>Smaller diameters allowing for stronger construction</p> Signup and view all the answers

    What is a primary advantage of the fin and stud attachments on double pipe exchangers?

    <p>Enhanced total heat transfer surface</p> Signup and view all the answers

    In double pipe exchangers, why are hairpin or serpentine configurations preferred in certain applications?

    <p>To allow for longer retention times and improved heat transfer</p> Signup and view all the answers

    What role do return bends serve in the construction of hairpin exchangers?

    <p>Connect the inner pipes or tube bundles</p> Signup and view all the answers

    What is the primary reason for using fins or studs attached to the inner pipe?

    <p>To increase the heat transfer surface</p> Signup and view all the answers

    What is the main advantage of the counter-current design in Figure 1?

    <p>It increases the heat transfer rate</p> Signup and view all the answers

    Why is the outer pipe often welded directly to the inner pipe in a double-pipe exchanger?

    <p>To provide structural support</p> Signup and view all the answers

    What is the result of using a jacketed pipe arrangement in a double-pipe exchanger?

    <p>Increased heat transfer area</p> Signup and view all the answers

    What is the primary function of the annulus space in a double-pipe exchanger?

    <p>To allow for fluid flow</p> Signup and view all the answers

    What is the primary application of a steam-jacketed line in a double-pipe exchanger?

    <p>To heat a process fluid</p> Signup and view all the answers

    What is a disadvantage of the U-tube design mentioned in the text?

    <p>Limited heating surface due to tube bending</p> Signup and view all the answers

    What is an advantage of the U-Tube exchangers mentioned in the text?

    <p>Ease of accessing shell interior for cleaning</p> Signup and view all the answers

    Why are U-Tube exchangers recommended to have the fouling fluid on the shell side?

    <p>Enhancement of heat transfer efficiency</p> Signup and view all the answers

    What is a key advantage of the floating head exchanger design?

    <p>Convenient removal of tube bundle for repairs</p> Signup and view all the answers

    What is a notable disadvantage of the floating head exchanger design?

    <p>Potential for leaks at the floating head flange</p> Signup and view all the answers

    What is a feature of fixed tube sheet exchangers that contributes to easy tube maintenance?

    <p>Tubesheets welded to the shell and straight tubes</p> Signup and view all the answers

    Why is it easier to maintain and clean tubes in fixed tube sheet exchangers compared to other designs?

    <p>Simple end cover removal</p> Signup and view all the answers

    Which design type mentioned in the text allows for simple replacement of leaking tubes?

    <p>Floating head exchangers</p> Signup and view all the answers

    What is a notable challenge of the U-tube design in terms of heating surface?

    <p>Reduction in heating surface due to bending</p> Signup and view all the answers

    What is a unique advantage of U-Tube exchangers compared to fixed tube sheet exchangers?

    <p>Simplicity of tube bundle removal</p> Signup and view all the answers

    Which type of heat exchanger design is the most common according to the text?

    <p>Shell and tube</p> Signup and view all the answers

    What is the key advantage of the U-Tube exchanger design mentioned in the text?

    <p>Simple tube maintenance</p> Signup and view all the answers

    In a U-Tube exchanger, how are the two ends of the U-shaped tubes secured?

    <p>Fixed to a single tubesheet</p> Signup and view all the answers

    What is the purpose of the horizontal partition in a larger U-tube exchanger?

    <p>Directing flow into the tubes</p> Signup and view all the answers

    Which type of exchanger design is well suited for high temperature and high pressure applications?

    <p>U-tube</p> Signup and view all the answers

    What is the function of the outer shell in a shell-and-tube heat exchanger?

    <p>Containing tubes</p> Signup and view all the answers

    What is the primary purpose of baffles in shell-and-tube heat exchangers?

    <p>To direct the shell fluid flow over the tube surface</p> Signup and view all the answers

    What is the term used to describe the horizontal distance or spacing between baffles?

    <p>Baffle pitch</p> Signup and view all the answers

    What is the benefit of using segmental baffles in shell-and-tube heat exchangers?

    <p>They provide additional support for the tubes along their length</p> Signup and view all the answers

    Why is chemical cleaning limited to tubeside fouling fluids in certain heat exchangers?

    <p>Because the tubesheets and tubes must be removed for full inspection and repairs</p> Signup and view all the answers

    What is the purpose of annular ring baffles in shell-and-tube heat exchangers?

    <p>To direct the shell fluid flow in an outward and inward direction</p> Signup and view all the answers

    What is a design consideration for the baffle pitch in shell-and-tube heat exchangers?

    <p>Maximizing heat transfer without significantly increasing the pressure drop</p> Signup and view all the answers

    What is a key advantage of the U-Tube exchanger design mentioned in the text?

    <p>Ease of tube bundle removal</p> Signup and view all the answers

    What is a notable disadvantage of the floating head exchanger design mentioned in the text?

    <p>Increased shell stresses when tubes expand at different rates</p> Signup and view all the answers

    What complicates inspection, cleaning, and repairs on the shell side in the fixed tubesheet exchanger design?

    <p>Difficult access to tubesheets</p> Signup and view all the answers

    What major factor contributes to the challenges related to fixed tubesheet exchangers' maintenance and tube repair?

    <p>Difficulty in accessing tube maintenance</p> Signup and view all the answers

    Why is the outer wall of the U-Tube bend designed to have a minimum bend radius?

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

    What are the Floating Head exchangers designed to allow without causing undue stress?

    <p>Different expansion rates of tubes and the shell</p> Signup and view all the answers

    What is a notable restriction faced when conducting tube repairs in U-tube exchangers?

    <p>Repair access limited to only the outside rows</p> Signup and view all the answers

    Why is fouling often recommended to happen on the shell side in U-Tube exchangers?

    <p>To increase heat transfer efficiency</p> Signup and view all the answers

    What makes repair and inspection on the shell side very difficult in fixed tube sheet exchangers?

    <p>Limited access through end covers</p> Signup and view all the answers

    What aspect of U-Tube design involving the minimum bend radius impacts the number of tubes that can be fit inside a shell?

    <p>Tube thinning prevention</p> Signup and view all the answers

    What design element ensures that the entire shell of a reboiler is flooded?

    <p>The attachment to the tower</p> Signup and view all the answers

    What causes continuous circulation (thermosyphon) to occur through the reboiler?

    <p>The density of the liquid in the tower</p> Signup and view all the answers

    Why might varying the level controller setpoint in a reboiler vary the level of condensate in the tube side of the exchanger?

    <p>To expose more or less heating surface to the steam</p> Signup and view all the answers

    In a low-pressure feedwater heater, where does the steam condense and collect before heating the feedwater?

    <p>In the bottom of the shell</p> Signup and view all the answers

    What role does a vent line from the shell serve in a low-pressure feedwater heater?

    <p>To carry non-condensable gases</p> Signup and view all the answers

    Why might a heater trip if the condensate level becomes too high in a feedwater heater?

    <p>To avoid damage due to high pressure</p> Signup and view all the answers

    What happens to the hotter condensate in the flash box before entering the hot well in a low-pressure feedwater heater?

    <p>It vaporizes to reduce pressure</p> Signup and view all the answers

    What controls the level of condensate in the tube side of a feedwater heater?

    <p>A level controller</p> Signup and view all the answers

    What is a primary function of feedwater heating in steam generating systems?

    <p>To improve efficiency of the steam cycle</p> Signup and view all the answers

    Why is feedwater heating recommended in industrial plants?

    <p>To improve the efficiency of the steam cycle</p> Signup and view all the answers

    What is the primary function of the weir plate in a reboiler?

    <p>To ensure the tubes remain covered with liquid</p> Signup and view all the answers

    Which type of reboiler depends on gravity for circulation of the liquid through the unit?

    <p>Kettle type reboiler</p> Signup and view all the answers

    What is the purpose of the shell in a reboiler?

    <p>To house the tube bundle</p> Signup and view all the answers

    What collects in the vapour space above the tube bundle in a reboiler?

    <p>Vapour that is produced</p> Signup and view all the answers

    What is a characteristic of the kettle type reboiler?

    <p>It has a large liquid volume and is easily accessible for maintenance</p> Signup and view all the answers

    What is a difference between the kettle type reboiler and the horizontal thermosyphon reboiler?

    <p>The kettle type reboiler has a vapour space above the tube bundle, while the horizontal thermosyphon reboiler does not</p> Signup and view all the answers

    What is the key advantage of a kettle type reboiler?

    <p>Easy maintenance and accessibility for cleaning</p> Signup and view all the answers

    What distinguishes a horizontal thermosyphon reboiler from other types of reboilers?

    <p>Absence of a vapour space above the tubes</p> Signup and view all the answers

    In the context of reboilers, what is the purpose of the vertical weir plate?

    <p>To ensure the tubes remain covered with liquid</p> Signup and view all the answers

    Which feature of a kettle type reboiler facilitates the circulation of liquid through the unit?

    <p>A level control valve downstream of the weir</p> Signup and view all the answers

    What is the design consideration for the liquid flow in a horizontal thermosyphon reboiler?

    <p>Gravity-driven liquid circulation</p> Signup and view all the answers

    How does a kettle type reboiler help in the heating and stripping of vapour in a fractionating tower?

    <p>By returning reboiler vapours to the attached vessel</p> Signup and view all the answers

    In a multiple effect evaporator system, low-pressure feedwater heaters are typically located between which components?

    <p>Hot well or extraction pumps and the dearator</p> Signup and view all the answers

    What is the term used to describe the process of heating the boiler feedwater before it enters the economizer section of the steam generator?

    <p>Pre-heating</p> Signup and view all the answers

    What does a float-operated trip gear in a low-pressure feedwater heater do if the condensate level becomes too high?

    <p>Trips the heater, closes the inlet and outlet valves, and opens the bypass valve</p> Signup and view all the answers

    What is the purpose of the flash box in a low-pressure feedwater heater?

    <p>Collection of non-condensable gases</p> Signup and view all the answers

    How does varying the level controller setpoint affect the operation of a feedwater heater?

    <p>Varies the level of condensate in the tube side to control process</p> Signup and view all the answers

    What happens to the flash steam in a low-pressure feedwater heater?

    <p>It is condensed and flows to a condensate return header</p> Signup and view all the answers

    What significant feature is present in a power plant cycle's low-pressure feedwater heater to allow any excess steam to exit?

    <p>Vent line</p> Signup and view all the answers

    What role does the liquid seal leg serve in a low-pressure feedwater heater?

    <p>Prevents steam from exiting the shell bottom</p> Signup and view all the answers

    What is the function of the level controller in a feedwater heater?

    <p>Vary the level of condensate to adjust process parameters</p> Signup and view all the answers

    What is the primary importance of feedwater heating in steam generating systems?

    <p>Improving the efficiency of the steam cycle</p> Signup and view all the answers

    How are the flow channels created in a plate-and-frame heat exchanger?

    <p>The holes in the plates create the channels</p> Signup and view all the answers

    What is the purpose of the gaskets in a plate-and-frame heat exchanger?

    <p>To prevent leakage between plates</p> Signup and view all the answers

    What is the direction of flow for the 'hot' and 'cold' exchange fluids in a plate-and-frame exchanger?

    <p>Hot fluid flows up while cold fluid flows down</p> Signup and view all the answers

    What is the typical spacing between adjacent plates in a plate-and-frame heat exchanger?

    <p>Five millimeters</p> Signup and view all the answers

    How is the flow distribution directed in a plate-and-frame heat exchanger?

    <p>By the gaskets around the holes</p> Signup and view all the answers

    What pattern is present on the plates of a plate-and-frame heat exchanger to enhance fluid flow?

    <p>Alternating ridges and grooves</p> Signup and view all the answers

    What is the primary function of gaskets in a plate-and-frame heat exchanger?

    <p>To prevent leakage between plates and to atmosphere</p> Signup and view all the answers

    Why are plate-and-frame exchangers not suitable for very dirty fluids?

    <p>Because small spacing between plates restricts flow</p> Signup and view all the answers

    What makes plate-and-frame exchangers capable of rapid start-up?

    <p>High turbulence and efficiency</p> Signup and view all the answers

    Why are Plate-and-Frame Exchangers considered vibration-free?

    <p>Because no insulation is required</p> Signup and view all the answers

    What can be a consequence of velocities between plates being low in plate-and-frame exchangers?

    <p>Poor flow distribution</p> Signup and view all the answers

    What is a limitation of plate-and-frame exchangers in terms of pressure?

    <p>Limited to applications where pressure doesn’t exceed 2.07 MPa</p> Signup and view all the answers

    Why do plate-and-frame exchangers require relatively small space for dismantling and cleaning?

    <p>Since they are compact and require less space</p> Signup and view all the answers

    What distinguishes plate-and-frame exchangers from shell-and-tube exchangers in terms of heat transfer surface area?

    <p>They require only one-third to one-half of the surface area of shell-and-tube exchangers</p> Signup and view all the answers

    Why does the low velocity between plates in plate-and-frame exchangers create poor flow distribution?

    <p>Because less than 0.1 m/s is considered poor</p> Signup and view all the answers

    What differentiates plate-and-frame exchangers from shell-and-tube exchangers in terms of leakage detection?

    <p>Plate-and-frame exchangers have immediate outer leakage detection compared to shell-and-tube exchangers</p> Signup and view all the answers

    What is the function of the gaskets in a plate-and-frame heat exchanger?

    <p>Prevent leaks between plates and to the external environment</p> Signup and view all the answers

    Why are the flow channels in a plate-and-frame heat exchanger referred to as 'pipes'?

    <p>They are continuously enclosed tubes within the plates</p> Signup and view all the answers

    How does the plate-and-frame design ensure turbulent flow between plates?

    <p>Through the corrugated pattern of the plates creating ridges and grooves</p> Signup and view all the answers

    What is the significance of the spacing between adjacent plates in a plate-and-frame heat exchanger?

    <p>It determines the resistance to flow between plates</p> Signup and view all the answers

    In a plate-and-frame exchanger, what directs the flow distribution of the exchange fluids?

    <p>The circumferential gaskets around the inlet and outlet ports</p> Signup and view all the answers

    How are the inlet and outlet ports arranged in a plate-and-frame heat exchanger?

    <p>In the corners of each plate</p> Signup and view all the answers

    What is NOT a component of a Plate and Frame heat exchanger?

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

    For Plate-and-Frame exchangers, what is the effect of low flows between plates?

    <p>Creation of stagnant regions</p> Signup and view all the answers

    What is a significant disadvantage of Plate-and-Frame exchangers related to pressure?

    <p>Limited to low pressures</p> Signup and view all the answers

    Why are Plate-and-Frame exchangers not recommended for viscous fluids?

    <p>Restriction due to spacing</p> Signup and view all the answers

    What happens if a Plate-and-Frame exchanger is used for toxic fluids that may form explosive mixtures with air?

    <p>Risk of leakage to atmosphere</p> Signup and view all the answers

    What limits the suitability of Plate-and-Frame exchangers for air coolers and gas-to-gas services?

    <p>High friction factor and small entry ports</p> Signup and view all the answers

    What is a limitation in using Plate-and-Frame exchangers for fluids prone to fouling?

    <p>Restriction due to plate clearance</p> Signup and view all the answers

    Why does Plate-and-Frame exchangers require new gaskets after a certain number of disassemblies?

    <p>Degradation of gaskets</p> Signup and view all the answers

    How do Plate-and-Frame exchangers ensure immediate leakage detection?

    <p>Visible external fluid discharge</p> Signup and view all the answers

    What allows for rapid modification of the rating of a Plate-and-Frame exchanger?

    <p>Ease of plate addition or removal</p> Signup and view all the answers

    What is the primary concern in controlling an aerial cooler?

    <p>Changing the speed of the fans</p> Signup and view all the answers

    What does a bay in an aerial cooler typically refer to?

    <p>A section of the cooler with one or more tube bundles and dedicated fans</p> Signup and view all the answers

    In what case are adjustable louvres commonly used in an aerial cooler?

    <p>To control the fluid outlet temperature</p> Signup and view all the answers

    What is the purpose of recirculation louvres in an aerial cooler?

    <p>To direct warm discharge air back to the fan inlet</p> Signup and view all the answers

    Why would an aerial cooler in very warm ambient conditions be operated with all available fans running at full speed and the louvres wide open?

    <p>To attain sufficient cooling</p> Signup and view all the answers

    What is the primary method of maintaining a steady outlet temperature in an aerial cooler when precise control is crucial for process reasons?

    <p>Changing the speed of the fans with variable frequency drives</p> Signup and view all the answers

    How are the louvres at the entrance or exit of the cooler directed to control the airflow?

    <p>Throttling the louvres</p> Signup and view all the answers

    In which scenario might hot air be recirculated back to the inlet of an aerial cooler?

    <p>During winter</p> Signup and view all the answers

    What adjustment is commonly made by the temperature transmitter on the outlet flow of an aerial cooler?

    <p>Modulating the frequency to the motor</p> Signup and view all the answers

    What is a potential solution to help lower the product temperature if an aerial cooler is undersized and cannot achieve sufficient cooling even with all fans operating?

    <p>Running water down onto the cooling coils</p> Signup and view all the answers

    What is a common feature of air-cooled exchangers according to the text?

    <p>Usage of fins for improved heat exchange efficiency</p> Signup and view all the answers

    What is the main purpose of induced draft air coolers as described in the text?

    <p>To force air across tubes to enhance heat exchange</p> Signup and view all the answers

    In what scenario is a combination of aerial cooling followed by water cooling recommended?

    <p>When fluids must be cooled below ambient temperature</p> Signup and view all the answers

    What would be a concern in using a water-cooled exchanger instead of the aerial cooler for cooling fluids?

    <p>Need for maintenance due to fouling on the cooling waterside</p> Signup and view all the answers

    What is the role of box headers in induced draft coolers?

    <p>To act as enclosures for the tube ends</p> Signup and view all the answers

    Why are fins attached to the outside of tubes in air-cooled exchangers?

    <p>To enhance the efficiency of heat exchange</p> Signup and view all the answers

    What determines the complexity of the control scheme in an aerial cooler?

    <p>The temperature control required</p> Signup and view all the answers

    Why must aerial coolers be cleaned regularly?

    <p>To remove accumulated airborne particles</p> Signup and view all the answers

    What is the purpose of installing screens over the fan inlet in certain environments?

    <p>To ease cleaning by preventing plugging</p> Signup and view all the answers

    What is the effect of blocked coils in an aerial cooler?

    <p>Reduced air flow and recycling</p> Signup and view all the answers

    What controls the air temperature below the tube bundle in an aerial cooler?

    <p>Recirculation louvres</p> Signup and view all the answers

    What is the relationship between the control of inlet louvres and the outlet fluid temperature controller?

    <p>The inlet louvres are controlled by the outlet fluid temperature controller</p> Signup and view all the answers

    How are the side, inlet louvres typically controlled in an aerial cooler?

    <p>Controlled by the outlet fluid temperature controller</p> Signup and view all the answers

    What is the purpose of the recirculation louvres in an aerial cooler?

    <p>To control the air temperature below the tube bundle</p> Signup and view all the answers

    Why are screens commonly installed over the fan inlet in certain environments for aerial coolers?

    <p>To prevent airflow restriction due to airborne particle accumulation</p> Signup and view all the answers

    What is a common consequence of not cleaning aerial coolers regularly due to plugging?

    <p>Recycling of airflow within the fan</p> Signup and view all the answers

    How does the complexity of the control scheme in an aerial cooler relate to the required temperature control precision?

    <p>It is directly proportional to the required temperature control precision</p> Signup and view all the answers

    What happens when sufficient cooling cannot be attained in an aerial cooler due to restricted airflow?

    <p>The incoming air becomes warmer</p> Signup and view all the answers

    For which type of fluids is aerial cooler preferred?

    <p>Fluids at least 55°C</p> Signup and view all the answers

    In air-cooled exchangers, what is the purpose of attaching fins to the outside of tubes?

    <p>To improve the efficiency of heat exchange</p> Signup and view all the answers

    What is the common feature of forced and induced draft air coolers?

    <p>Horizontal bank of tubes</p> Signup and view all the answers

    When might a combination of aerial cooling followed by water cooling be efficient and economical?

    <p>When fluids need to be cooled well below ambient temperature</p> Signup and view all the answers

    What is the key difference between forced and induced draft air coolers?

    <p>Direction of the air discharge</p> Signup and view all the answers

    How is the fluid directed through the tubes in forced and induced draft coolers?

    <p>Directed by baffles inside the box headers</p> Signup and view all the answers

    What is the primary concern with an aerial cooler?

    <p>Maintaining a steady outlet temperature for the cooled fluid</p> Signup and view all the answers

    In an aerial cooler, how are fan speeds usually adjusted?

    <p>Using variable frequency motor drives</p> Signup and view all the answers

    What method is commonly employed in an aerial cooler when temperature variations must be minimal for process reasons?

    <p>Using variable frequency motor drives</p> Signup and view all the answers

    What is a technique mentioned in the text to help achieve sufficient cooling in an aerial cooler when coolers are undersized?

    <p>Spraying water onto the cooling coils</p> Signup and view all the answers

    In what conditions might louvres direct warm air back to the fan inlet in an aerial cooler?

    <p>Very warm ambient conditions</p> Signup and view all the answers

    How are louvres controlled in an aerial cooler to adjust the air flow?

    <p>Directed by a temperature transmitter</p> Signup and view all the answers

    What is a common method used to achieve a very steady temperature in an aerial cooler?

    <p>Adjusting fan speed with variable frequency motor drives</p> Signup and view all the answers

    During which conditions in an aerial cooler might louvres be kept wide open with fans at full speed?

    <p>When ambient temperatures are moderate</p> Signup and view all the answers

    What can be used to help achieve cooling in an aerial cooler when the set temperature cannot be reached through conventional means?

    <p>Spraying water onto the cooling coils</p> Signup and view all the answers

    What is a possible enhancement strategy in very cold conditions to ensure good cooling in an aerial cooler?

    <p>Recirculating some warm discharge air</p> Signup and view all the answers

    Which type of aerial condenser design is most common in smaller sizes and when liquid removal is less critical?

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

    Which tube bundle arrangement for aerial condensers requires less room than horizontal types and is less affected by wind than vertical types?

    <p>V-Frame</p> Signup and view all the answers

    What feature of aerial condenser tube bundles allows them to be cleaned by lancing or high-pressure water jet?

    <p>Plugs alignment</p> Signup and view all the answers

    In which type of aerial cooler tube bundle are the tubes finned to create a larger heat transfer surface?

    <p>V-Frame</p> Signup and view all the answers

    Which arrangement of aerial condenser tube bundles is popular in smaller sizes where floor space is limited and liquid drainage is critical?

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

    Which type of aerial condenser design provides a large exchange surface without excessive floor space in large designs such as steam condensers?

    <p>V-Frame</p> Signup and view all the answers

    What does Figure 30 illustrate?

    <p>External view of a box header</p> Signup and view all the answers

    Why do box headers have a larger inlet diameter compared to the outlet?

    <p>Due to larger volume of fluid in the inlet state</p> Signup and view all the answers

    What is a critical requirement for aerial condensers in freezing temperatures?

    <p>Maintaining condensate temperature</p> Signup and view all the answers

    What is a potential consequence of removing a large number of threaded cleaning plugs from box header tubes?

    <p>Leakage source</p> Signup and view all the answers

    What is a possible outcome of freezing within aerial condenser tubes?

    <p>Plugging and tube breakage</p> Signup and view all the answers

    Why are box header threaded cleaning plugs mentioned as a source of potential leaks?

    <p>Due to poor design</p> Signup and view all the answers

    What makes aerial condenser designs more complicated than aerial cooler designs?

    <p>Dealing with the removal of latent heat and two phases of fluid</p> Signup and view all the answers

    Which tube bundle configuration is popular in smaller sizes where floor space is limited?

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

    In which condenser type are the tube bundles less affected by wind and provide a large exchange surface without excessive floor space?

    <p>V-Frame</p> Signup and view all the answers

    What role do the plugs in the header boxes serve in aerial condensers?

    <p>Facilitate cleaning of the tubes</p> Signup and view all the answers

    Which exchanger design is most common in smaller sizes and when liquid removal is less critical?

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

    What factor affects the performance of vertical aerial condenser units?

    <p>Wind direction</p> Signup and view all the answers

    What function can the shaded dots represent in the external, end view of a box header as per Figure 30?

    <p>Threaded cleaning plugs</p> Signup and view all the answers

    What is the purpose of drains and vents typically fitted in box headers?

    <p>To remove condensate and purge the system</p> Signup and view all the answers

    Why is careful control of the outlet condensate temperature especially critical in aerial condensers during freezing temperatures?

    <p>To avoid blockage and tube damage due to ice formation</p> Signup and view all the answers

    What consequence could freezing inside aerial condenser tubes lead to?

    <p>Tube blockage and potential damage</p> Signup and view all the answers

    Why are aerial condensers, especially steam condensers, required to have careful control of outlet condensate temperature?

    <p>To prevent freezing and tube damage from ice formation</p> Signup and view all the answers

    What specific issue could occur if freezing causes the tubes to break in an aerial condenser?

    <p>Possible safety hazards</p> Signup and view all the answers

    What type of air-cooled cooling towers operate effectively in locations with relatively constant winds and large open spaces away from obstructions?

    <p>Atmospheric cooling towers</p> Signup and view all the answers

    Which type of cooling tower shown in the figures contains nozzles that spray water downward and operates by natural induction?

    <p>Spray filled towers</p> Signup and view all the answers

    What is the purpose of louvres on the sides of atmospheric cooling towers?

    <p>Help contain the water inside the tower</p> Signup and view all the answers

    In the context of cooling towers, what would be the main role of the perforated overhead flume or spray nozzles found in the towers?

    <p>Create airflow by natural induction</p> Signup and view all the answers

    What does the presence of fill or packing made of wood or plastic slats in an atmospheric cooling tower facilitate?

    <p>Enhanced evaporation and cooling</p> Signup and view all the answers

    Which factor determines the effectiveness of atmospheric cooling towers?

    <p>Wind velocity</p> Signup and view all the answers

    What is the primary advantage of using hyperbolic cooling towers?

    <p>Minimized power consumption</p> Signup and view all the answers

    In what conditions do hyperbolic cooling towers function best?

    <p>Stable heat load locations</p> Signup and view all the answers

    What distinguishes counterflow hyperbolic cooling towers from crossflow towers?

    <p>Direction of air flow</p> Signup and view all the answers

    What does the operator of natural draft cooling towers have minimal control over?

    <p>Ambient air temperature</p> Signup and view all the answers

    What are some of the key operating variables that should be checked for natural draft cooling towers?

    <p>Cooling water quality</p> Signup and view all the answers

    Why are hyperbolic cooling towers considered to be expensive to construct?

    <p>Height of the tower</p> Signup and view all the answers

    Which type of cooling tower involves louvres to direct airflow for containing water inside the tower?

    <p>Atmospheric cooling towers</p> Signup and view all the answers

    What characteristic is NOT associated with atmospheric cooling towers?

    <p>Use of nozzles to spray water downward</p> Signup and view all the answers

    Which feature is unique to spray-filled atmospheric cooling towers?

    <p>Absence of fill materials</p> Signup and view all the answers

    What purpose do the packing made of wood or plastic slats serve in an atmospheric tower?

    <p>To enhance evaporation and cooling</p> Signup and view all the answers

    What distinguishes an atmospheric tower with packing material from a spray-filled tower?

    <p>The breaking of water into fine droplets by the packing</p> Signup and view all the answers

    In atmospheric cooling towers, why do louvres play a crucial role in tower operation?

    <p>To control and direct airflow</p> Signup and view all the answers

    What causes air flow in hyperbolic cooling towers?

    <p>Density differential between interior heated air and cooler exterior air</p> Signup and view all the answers

    Why are hyperbolic towers suitable for large electrical generation plants?

    <p>Stable heat load operation</p> Signup and view all the answers

    What kind of towers are hyperbolic towers made of primarily?

    <p>Steel-reinforced concrete shell</p> Signup and view all the answers

    In which type of hyperbolic towers is the air flow counter to the water flow?

    <p>Counterflow towers</p> Signup and view all the answers

    What is the advantage in terms of maintenance costs for hyperbolic towers?

    <p>No need for power consuming fans</p> Signup and view all the answers

    Why do hyperbolic towers operate best in locations with high relative humidity?

    <p>To enhance the cooling efficiency</p> Signup and view all the answers

    What is the primary purpose of the fans in an induced draft cooling tower?

    <p>To draw air upwards and discharge hot, moisture-laden air away from the tower</p> Signup and view all the answers

    What material is often used for the fill in many cooling towers to promote maximum air contact time and minimize airflow restriction?

    <p>Redwood or pressure-treated Douglas fir</p> Signup and view all the answers

    In a crossflow induced draft cooling tower, how does the air flow compared to the water flow?

    <p>Perpendicular to the water flow</p> Signup and view all the answers

    What is the function of side louvres in induced draft towers?

    <p>To direct air evenly into the tower</p> Signup and view all the answers

    Which type of induced draft tower design requires large electric motors due to the path the air takes?

    <p>Counterflow induced draft towers</p> Signup and view all the answers

    In a power plant cycle with a condensing turbine, which cooling tower design occupies less floor space for a given capacity?

    <p>Counterflow induced draft tower</p> Signup and view all the answers

    What is the advantage of film type fill made of PVC in cooling towers?

    <p>Chemical resistance</p> Signup and view all the answers

    What causes water droplets to be left behind in induced draft towers?

    <p>Drift eliminators</p> Signup and view all the answers

    Why is the total travel path of air longer in a crossflow design compared to a counterflow design?

    <p>To prevent recirculation of warm air</p> Signup and view all the answers

    How does a counterflow cooling tower help minimize energy costs compared to a crossflow tower?

    <p>By reducing the air path resistance</p> Signup and view all the answers

    What type of tower has the fan located at the base to force ambient air into the tower?

    <p>Forced draft tower</p> Signup and view all the answers

    Why are drift eliminators used in forced draft cooling towers?

    <p>To capture entrained water from the air</p> Signup and view all the answers

    Which material is NOT commonly used for paneling the exterior walls of a forced draft tower?

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

    Why are forced draft towers preferred for handling mostly dry air?

    <p>To reduce erosion and water condensation problems</p> Signup and view all the answers

    What is a notable disadvantage of forced draft towers compared to induced draft towers?

    <p>Less suited for cold weather operation</p> Signup and view all the answers

    Where is the forced draft tower fan located?

    <p>At the base of the tower</p> Signup and view all the answers

    How does the counterflow induced draft tower prevent recirculation of warm air?

    <p>By discharging hot, moisture-laden air upward and away from the air entering at the bottom</p> Signup and view all the answers

    What component in mechanical draft towers causes any water droplets to be left behind?

    <p>Drift eliminators</p> Signup and view all the answers

    In a crossflow induced draft cooling tower, how does the air flow through the packing?

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

    What is the main advantage of a counterflow induced draft tower compared to other designs?

    <p>Lower energy costs due to less resistance to airflow</p> Signup and view all the answers

    Why is PVC favored as a material for cooling tower fill?

    <p>For its resistance to chemicals</p> Signup and view all the answers

    What is the purpose of side louvres in induced draft towers?

    <p>To direct airflow evenly into the tower</p> Signup and view all the answers

    How does the crossflow design of a cooling tower differ from counterflow design?

    <p>It has a longer travel path for air and less resistance to airflow</p> Signup and view all the answers

    In what way do induced draft towers contribute to energy efficiency?

    <p>By reducing fan power requirements</p> Signup and view all the answers

    What distinguishes film type fill from splash type fill in cooling towers?

    <p>Arrangement of thin sheets spaced closely together</p> Signup and view all the answers

    Why are induced draft towers typically preferred over forced draft towers in cooling systems?

    <p>Due to their energy efficiency</p> Signup and view all the answers

    What distinguishes a forced draft cooling tower from an induced draft cooling tower?

    <p>Forced draft towers have the fan inside the tower structure while induced draft towers do not.</p> Signup and view all the answers

    What problem is specifically mentioned as a drawback of forced draft towers in cold weather operation?

    <p>Ice build-up on fan blades due to moisture in the air.</p> Signup and view all the answers

    What is the primary function of drift eliminators in a forced draft cooling tower?

    <p>To remove entrained water from the air before it leaves the tower.</p> Signup and view all the answers

    Why are louvres not present in the exterior walls of a forced draft cooling tower?

    <p>To allow ambient air to enter only through the fan located at the base.</p> Signup and view all the answers

    How does the presence of fill in a forced draft cooling tower impact the air and water flow?

    <p>It forces the air to flow downward through the fill while water flows upward.</p> Signup and view all the answers

    Why are forced draft towers less suited to cold weather operation compared to induced draft towers?

    <p>Because the fan in forced draft towers can lead to ice build-up on the blades.</p> Signup and view all the answers

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