Q.1
##### In the given equation, what do you understand by the enthalpy balance, which element is it applied for?
• a) Feed
• b) Steam
• c) Vapour
• d) Evaporator wall
Q.2
##### Which one of the following is not an assumption taken before applying enthalpy balance on the evaporator?
• a) No solid should precipitate out from the concentrating solution
• b) The superheat and sub-cooling conditions of the condensable steam is negligible
• c) No fouling should occur on the evaporator surface
• d) Flow of non-condensable gas is negligible
Q.3
• a) True
• b) False
Q.4
##### The amount of heat transferred through the evaporator wall is actually equal to which one of the following?
• a) The steam condensing on the outer wall
• b) The heat carried by the vapour leaving the evaporator
• c) The total heat of increasing the feed temperature to boiling point
• d) The total heat of increasing the feed temperature to boiling point and the vapour
Q.5
##### If Qs is heat supplied by the steam and Qf is the heat evolved in the feed, then the overall heat transfer coefficient can be represented as? Here AF = Area of film and AW = Area of wall.
• a) U = Qf/AW ΔT
• b) U = Qs/AF ΔT
• c) U = (Qs – Qf)/AW ΔT
• d) U = (Qs – Qf)/AF ΔT
Q.6
• a) 52600 KJ
• b) 56200 KJ
• c) 2272.6 MJ
• d) 47600 KJ
Q.7
##### What is the overall heat transfer coefficient of an evaporator setup of internal diameter is 30cm andlength cylinder in order to evaporate 10kg of water from a feed of 50kg at a temperature ofto a final temperature of 150℃? Saturated temperature of steam = 160℃
• a) 503 kJ/m2 K
• b) 553 kJ/m2 K
• c) 5553 kJ/m2 K
• d) 5053 kJ/m2 K
Q.8
• a) 1.10m2
• b) 1.27m2
• c) 2.17m2
• d) 1.17m2
Q.9
##### Why is the calculated heat transfer area more than the inner surface heat transfer area of the evaporator?
• a) Because the area is outer surface area
• b) Because the area is equivalent to a large diameter
• c) Because the area is on a diameter between outer and inner diameter
• d) Area is more than outer surface area
Q.10
• a)
• b)
• c)
• d)
Q.11
• a) 45.25 kg
• b) 44.25 kg
• c) 41.25 kg
• d) 43.25 kg