Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer).

Width and depth of grooves in the tube sheet holes normally are __________ inch respectively.

A. $$\frac{1}{8}$$ and $$\frac{1}{{64}}$$

B. $$\frac{1}{{64}}$$ and $$\frac{1}{8}$$

C. $$\frac{1}{2}$$ and 8

D. $$\frac{1}{2}$$ and 5

In most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter.

A. Less than

B. 1.25-1.50 times

C. 2.5 times

D. One-fourth of

Value of Peclet number = 0, is the representative of

A. Laminar flow

B. Complete back mixing

C. Plug flow

D. Eddy diffusivity = 0

The ideal size of round bubble caps to be used in industrial distillation column having a diameter of 3-6 metres is __________ cms.

A. 5

B. 15

C. 7.5

D. 50