For shell and tube heat exchanger, with increasing heat transfer area,
the purchased cost per unit heat transfer area
(A) Increases
(B) Decreases
(C) Remain constant
(D) Passes through a maxima
Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid (A) Remains unchanged (B) Increases (C) Increases or decreases depending on number of shell passes (D) Decreases
Last Answer : (D) Decreases
Description : In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate. (A) Increases (B) Decreases (C) Does not affect (D) May increase or decrease, depends on the type of baffle
Last Answer : (A) Increases
Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these
Last Answer : (C) Increases the overall heat transfer coefficient
Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film coefficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'
Last Answer : (D) All 'a', 'b' & 'c'
Description : The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by __________ times, when the number of tube passes is increased to 8. (A) 2 0.8 (B) 4 0.8 (C) 4 0.4 (D) 2 0.4
Last Answer : (B) 4 0.8
Description : Pick out the wrong statement. (A) Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient (B) In a shell and tube heat exchanger ... surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube
Last Answer : (C) S.I. unit of fouling factor is Watt/m2 .°K
Description : Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both ... steam on shell side (D) Shell and tube heat exchanger with air on shell side and steam inside tubes
Last Answer : (B) Finned tube heat exchanger with air outside and steam inside
Description : Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger? (A) Tube side pressure drop and the heat transfer rate (B) Convective heat transfer co-efficient (C) Effective tube surface area for convective heat transfer (D) All (A) (B) and (C)
Last Answer : (D) All (A) (B) and (C)
Description : For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it (A) Occupies smaller space (B) Is more economical (C) Is easy to operate and maintain (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same
Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume
Description : Extremely large or small volumes of fluids are generally best routed through the shell side of a shell and tube heat exchanger, because of the (A) Less corrosion problems (B) Flexibility possible in the baffle arrangement (C) Low pressure drop (D) High heat transfer co-efficient
Last Answer : (B) Flexibility possible in the baffle arrangement
Description : LMTD correction factor which is to be applied for a cross-flow heat exchanger increases with increase in the number of shell passes. Its value for a single pass cross flow heat exchanger is (A) 0 (B) 1 (C) > 1 (D) < 1
Last Answer : (D) < 1
Description : . If a single tube pass heat exchanger is converted to two pass, then for the same flow rate, the pressure drop per unit length in tube side will (A) Increase by 1.8 times (B) Decrease by 2 2 (C) Increase by 2 16 (D) Remain unchanged
Last Answer : (C) Increase by 2 16
Description : . In a shell and tube heat exchanger, the tube side heat transfer coefficient just at the entrance of the tube is (A) Infinity (B) Zero (C) Same as average heat transfer co-efficient for tube side (D) None of these
Last Answer : (A) Infinity
Description : Steam is to be condensed in a shell and tube heat exchanger, 5 m long with a shell diameter of 1 m. Cooling water is to be used for removing the heat. Heat transfer co-efficient ... ) Horizontal heat exchanger with steam on tube side (D) Horizontal heat exchanger with steam on shell side
Last Answer : (B) Vertical heat exchanger with steam on shell side
Description : Baffles in the shell side of a shell and tube heat exchanger (A) Increase the cross-section of the shell side liquid (B) Force the liquid to flow parallel to the bank (C) Increase the shell side heat transfer co-efficient (D) Decrease the shell side heat transfer co-efficient
Last Answer : (C) Increase the shell side heat transfer co-efficient
Description : The advantage of using a 1 - 2 shell and tube heat exchanger over a 1 - 1 shell and tube heat exchanger is (A) Lower tube side pressure drop (B) Lower shell side pressure drop (C) Higher tube side heat transfer co-efficient (D) Higher shell side heat transfer co-efficient
Last Answer : (C) Higher tube side heat transfer co-efficient
Description : In a shell and tube heat exchanger, floating head is used for (A) Large temperature differentials (B) High heat transfer co-efficient (C) Low pressure drop (D) Less corrosion of tubes
Last Answer : (A) Large temperature differentials
Description : Use of transverse baffles in a shell and tube heat exchanger is done to increase the (A) Rate of heat transfer (B) Flow velocity (C) Turbulence of shell side fluid (D) All (A), (B) and (C)
Description : Baffles provided on the shell side of a shell and tube heat exchanger are meant for (A) Providing support for the tubes (B) Improving heat transfer (C) Both 'a' & 'b' (D) Preventing the fouling of tubes & stagnation of shell side fluid
Last Answer : C) Both 'a' & 'b'
Description : Are some heat transfer services more prone to tube vibration that others for a shell and tube exchanger?
Last Answer : Bundle vibration can cause leaks due to tubes being cut at the baffle holes or tubes being loosened at the tubesheet joint. There are services that are more likely to cause bundle vibration ... if the baffle spacing is greater than 18 inches and single segmental. Source: Gulley Computer Associates
Description : Is there a quick rule-of-thumb to estimate a gas side heat-transfer rate inside the tubes of a shell and tube heat exchanger?
Last Answer : If you need to estimate a gas heat transfer rate or see if a program is getting a reasonable gas rate, use the following: h = 75 X Sq. Root(Op. pressure/100) The operating pressure is ... will be lower for the shell side or if there is more than one exchanger. Source: Gulley Computer Associates
Description : Heat transfer efficiency leading of energy conservation in a heat exchanger can be achieved by (A) Keeping the heat transfer surface clean (B) Enhancing the fluid pumping rate (C) Increasing the tube length (D) None of these
Last Answer : (A) Keeping the heat transfer surface clean
Description : In a shell and tube heat exchanger, square pitch compared to triangular pitch (A) Gives a higher shell side pressure drop (B) Gives a lower shell side pressure drop (C) Can pack more surface area into a shell of given diameter (D) None of these
Last Answer : (A) Gives a higher shell side pressure drop
Description : In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used (A) In low range of temperature differences (B) In high range of temperature differences (C) Because of its low cost (D) To prevent corrosion of the tube bundles
Last Answer : (B) In high range of temperature differences
Description : A concentric double pipe heat exchanger as compared to the shell and tube heat exchanger for the same heat load requires (A) Less heating surface (B) More space (C) Lower maintenance cost (D) None of these
Last Answer : (B) More space
Description : Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat ... drop through the exchanger is desired (D) Temperature of the incoming vapor is very high
Last Answer : (B) Supersaturated
Description : Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a ... recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators
Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators
Description : Vibrations in the tubes of a shell and tube heat exchanger is induced due to the (A) Flow of fluid on the tube and shell sides (B) Oscillations in the flow of shell/tube sides fluid (C) Vibrations ... piping and/or supports due to external reasons (D) All (A), (B) and (C)
Description : In a shell and tube heat exchanger, putting a longitudinal baffle across the shell, forces the shell side fluid to pass __________ through the heat exchanger. (A) Once (B) Twice (C) Thrice (D) Four times
Last Answer : (B) Twice
Description : Explain construction and working of shell and tube type heat exchanger. A ice plant producing 2000 Kg ice per day required the condenser. Suggest the type of condenser with justification.
Last Answer : Shell and tube heat exchanger consist of a bundle of round tubes placed inside the cylindrical shell.Tube axis parallel to that of shell. One fluid inside the tubes while the other over ... of heat rejection by the evaporation of water into an air stream traveling across the condensing coil.
Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side
Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger
Description : In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is (A) ∞ (B) 0 ... temperature (D) Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature
Last Answer : (B) 0
Description : Fouling factor' used in the design of a multipass shell and tube heat exchanger is a (A) Non-dimensional factor (B) Factor of safety
Last Answer : (B) Factor of safety
Description : __________ heat exchanger is the most suitable, when the temperature of shell side fluid is much higher than that of tube side. (A) Single pass, fixed tube sheet (B) U-tube (C) Three pass, fixed tube sheet (D) None of these
Last Answer : (B) U-tube
Description : Which type of heat exchanger is preferred for heavy heat loads? (A) Double pipe (B) Plate fine (C) Series and parallel set of shell and tube (D) None of these
Last Answer : (C) Series and parallel set of shell and tube
Description : In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell). (A) 0.25 D (B) 0.50 D (C) 0.75 D
Last Answer : (C) 0.75 D
Description : In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to __________ the velocity head. (A) Twice (B) Four times (C) Square root of (D) Square of
Last Answer : (B) Four times
Description : Air is best heated with steam in a heat exchanger of (A) Plate type (B) Double pipe type with fin on steam side (C) Double pipe type with fin on air side (D) Shell and tube type
Last Answer : (C) Double pipe type with fin on air side
Description : The main function of baffles provided in a shell and tube heat exchanger is to (A) Facilitate the cleaning of outer tube surface (B) Enhance turbulence (C) Hold the tubes in position (D) All 'a', 'b' & 'c'
Last Answer : (B) Enhance turbulence
Description : Pick out the wrong statement. (A) Orifice baffles are never used in a shell and tube heat exchanger (B) Pressure drop on the shell side of a heat exchanger depends upon tube pitch also
Last Answer : (A) Orifice baffles are never used in a shell and tube heat exchanger
Description : Shell side pressure drop in a shell and tube heat exchanger does not depend upon the (A) Baffle spacing & shell diameter (B) Tube diameter & pitch (C) Viscosity, density & mass velocity of shell side fluid (D) None of these
Last Answer : (D) None of these
Description : Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger? (A) Corrosiveness (B) Fouling characteristic (C) Viscosity (D) None of these
Description : Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3 /min) of density 800 kg/m3 and specific heat of ... mean temperature difference in °C is approximately (A) 32 (B) 37 (C) 45 (D) 50
Last Answer : (A) 32
Description : In case of a shell and tube heat exchanger, the minimum and maximum baffle spacing is respectively (where, D = inside diameter of the shell) (A) D/5 and D (B) D/2 and 2 D (C) D/4 and 2 D (D) D and 2 D
Last Answer : (A) D/5 and D
Description : A process stream of dilute aqueous solution flowing at the rate of10 Kg.s -1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s -1 . A 1 ... side (C) Parallel flow with process stream on shell side (D) Parallel flow with process stream on tube side
Last Answer : (A) Counter flow with process stream on shell side
Description : In a shell and tube heat exchanger, the shell side fluid velocity can’t be changed by changing the (A) Tube layout (B) Tube diameter (C) Tube pitch (D) Number of baffles
Last Answer : (B) Tube diameter
Description : Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter). (A) 0.2 D (B) 0.5 D (C) 0.66 D (D) 0.80 D
Last Answer : (A) 0.2 D
Description : It is not recommended to use a 1-2 shell and tube heat exchanger for a particular heat duty, whenever the LMTD correction factor is (A) > 0.75 (B) < 0.75 (C) < 0.50 (D) < 0.25
Last Answer : (B) < 0.75