Generally, no corrosion allowance in wall thickness of a part is required, if the thickness is more than ______________ mm?

A. Laminar flow
B. Complete back mixing
C. Plug flow
D. Eddy diffusivity = 0

A. Tall (say 30 metres), but is full of liquid
B. Tall but empty
C. Short (< 2 m) and housed indoor
D. None of these

A. < 12.5
B. > 3
C. > 5
D. 5-10

A. Practical limit reached, due to low heat transfer rate because of inadequate temperature
difference
B. Economic limit reached, when the plant cost exceeds the saving of steam
C. Both A. & B.
D. Neither A. nor B.

A. Double pipe heat exchanger
B. Multipass shell and tube heat exchanger
C. Fouling fluids
D. Counter flow of hot and cold fluids

A. 2
B. 1/2
C. 4
D. 1/4