Q.1.
Falling film evaporators are a subclass of long tube evaporators.
- a) True
- b) False
Q.2.
Falling film evaporators can be operated in _______________
- a) Counter-flow with the vapour
- b) Co-current flow with vapour
- c) Both co-current and counter-current
- d) Separate segments in any direction
Q.3.
Falling film evaporators are considered over climbing film evaporators because of which one of the following factor?
- a) Efficiency
- b) Product holdup
- c) Driving force requirement
- d) Temperature sensitivity
Q.4.
The applications of falling film and rising film are more or less same, but if industries have the cost capital, they go for falling film, why?
- a) It has high temperature gradient and natural convection
- b) Better efficiency of falling film
- c) It has less temperature gradient and natural convection
- d) No need for upward pressure
Q.5.
Falling film evaporators are best suited for pharmaceutical industries because
- a) It has high temperature gradient and natural convection
- b) Low pressure
- c) It has less temperature gradient and natural convection
- d) High headroom available
Q.6.
Falling film evaporators can be used with the fluid falling over
- a) (i)(ii)(iii)
- b) (i)(ii)
- c) (i)(iii)(iv)
- d) (i)(ii)(iii)(iv)
Q.7.
Falling film evaporators have __________ product holdup.
- a) Large
- b) Very high
- c) Low
- d) Zero
Q.8.
Which one of the following is not an advantage of falling film evaporator?
- a) Relatively low cost
- b) High headroom
- c) Large surface area for heating available
- d) Low product holdup
Q.9.
Which one of the following cannot be regarded as a demerit of falling film evaporator?
- a) High headroom requirement
- b) Corrosive fluids cannot be used
- c) Large product holdup
- d) Recirculation needed
Q.10.
The fluids in falling tube evaporator usually form a film inside the tubes but there are applications when the fluid forms a film outside the tube and falls subsequently.
- a) True
- b) False
Q.11.
In order to maintain conservation of mass as this fluid fall proceeds in a falling film evaporator, the downward vapour velocity ___________
- a) Decreases
- b) Increases
- c) Remains Same
- d) Oscillates
Q.12.
Recognize the falling film evaporator.
- a)
- b)
- c)
- d)