Heat Transfer
A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because
Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect
Boiling point elevation in a single effect system is much higher than that in any effect in a multieffect system
Total heat transfer area of all the effects is -less than that in a single effect evaporator system
Heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect system
Presence of a non-condensible gas decreases the condensing film co-efficient
All of these
Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes
Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature
EXAMIANS