Process Equipment and Plant Design MCQs

Question 1

In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference

Accepted Answer

Is always less than arithmetic average value

Answer

Is always more than arithmetic mean value and the geometric mean value

Answer

Is always less than arithmetic mean value, but more than geometric mean value

Answer

May be either more or less than geometric mean and arithmetic mean value depending upon whether the flow of stream is co-current or counter-current

Question 2

The wall thickness for a large high pressure pipeline is determined by the consideration of the

Accepted Answer

Circumferential pipewall tension

Answer

Axial tensile stress in the pipe

Answer

Forces exerted by static and dynamic action at bends

Answer

Temperature stresses

Question 3

Pick out the wrong statement pertaining to the design of a long tube vertical evaporator.

Accepted Answer

None of these

Answer

Tube dia is 3 - 6 cms, while tube length in 3 - 6 metres

Answer

Steam is fed to the shell, whereas the liquor is filled inside the tube

Answer

Liquor level is maintained at $${\frac{l}{3}^{{	ext{rd}}}}$$ to $$\frac{1}{2}$$ of the height of the tube

Question 4

Where does the maximum tensile strength occur in a thick cylindrical vessel subjected to internal pressure?

Accepted Answer

At the inner surface

Answer

At the mid thickness of the cylindrical wall

Answer

At the outer surface

Answer

None of these

Question 5

Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling.

Accepted Answer

NH 3

Answer

CO 2

Answer

SO 2

Answer

None of these

Question 6

For laminar flow (N Re < 2100) in steel pipe, the optimum inside pipe diameter is given by

Accepted Answer

D i, opt = 3 Q 0.36 .ρ 0.18

Answer

D i, opt = 3.9 Q 0.45 .ρ 0.23

Answer

D i, opt = 7.6 Q 0.36 .ρ 0.9

Answer

D i, opt = 3 Q 0.36 .ρ 1.86 .μ 0.08

Question 7

The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.

Accepted Answer

5

Answer

2

Answer

10

Answer

15

Question 8

Hoop (circumferential) stress induced in a thin walled 'Horton Sphere' used for the storage of liquid ammonia under pressure is

Accepted Answer

$$\frac{{{	ext{pD}}}}{{2{	ext{t}}}}$$

Answer

$$\frac{{{	ext{pD}}}}{{4{	ext{t}}}}$$

Answer

$$\frac{{{	ext{pD}}}}{{3{	ext{t}}}}$$

Answer

$$\frac{{{	ext{pD}}}}{{6{	ext{t}}}}$$

Question 9

A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of

Accepted Answer

2 0.8

Answer

2

Answer

2 0.2

Answer

None of these