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.Management Sciences
Category: Chemical Heat Transfer
The advantage of backward feed multiple effect evaporators over forward feed units is that___________________?
A. Heat sensitive material can be handled
B. There is no additional cost of pumping
C. Most concentrated liquid is at highest temperature
D. Equal heat transfer co-efficients exist in various effects
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be__________________?
A. Greater than that for un-insulated steam pipe
B. Less than that of the un-insulated steam pipe
C. Equal to that of the un-insulated steam pipe
D. Less than the steam pipe with 5 cms insulation
Fourier’s law applies to the heat transfer by__________________?
A. Convection
B. Radiation
C. Conduction
D. All A., B. & C.
Steam traps are provided in steam carrying pipelines to_________________?
A. Condense steam
B. Release excess steam pressure by bleeding steam
C. Remove condensate and inert gases
D. None of these
Black liquor generated during paper manufacture is concentrated in a___________________?
A. Single effect evaporator
B. Single effect evaporator followed by a crystalliser
C. Multiple effect evaporator
D. Multiple effect evaporators followed by a crystalliser
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
LMTD for counter-flow and parallel flow heat exchanger will be the same, when the_________________?
A. Cold fluid is heated to a certain temperature by condensing steam (isothermal fluid)
B. Outlet temperature of both the hot and cold fluid are same
C. Outlet temperature of hot fluid is less than the outlet temperature of the cold fluid
D. None of these
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