Question

Which of the following is not the advantage of falling film evaporator?

(a) Short residence time of liquid

(b) Good performance with small temperature difference across heating surfaces

(c) Operates at lower temperature difference than rising film evaporator

(d) Long residence time of liquid

This question was addressed to me in an interview for internship.

Asked question is from Evaporator topic in section Building Blocks of Dairy Processing of Dairy Engineering

Answer 1

The correct option is (d) Long residence time of liquid

For explanation I would say: The advantages claimed for the falling film evaporator are short residence time of liquid, good performance with small temperature difference across the heating surface. More effects can be used with falling film evaporator as it will operate with a lower temperature difference than climbing film evaporator.