Process Equipment and Plant Design

Question 1

Which of the following material is seldom used for pressure vessel construction?

Answer 1

Rimmed Steel

Question 2

The ratio of shear stress to shear strain is called

Answer 2

shear modulus

Question 3

25 percent cut segmental baffle means that the baffle

Answer 3

height is 75% of the I.D. of the shell.

Question 4

Liquid/petroleum fuel storage tanks are built underground (as in case of petrol pumps), when the storage capacity is less than __________ kilolitres.

Answer 4

45

Question 5

Le/D for fully open globe value may be around

Answer 5

300

Question 6

With increase in the number of shell passes, the value of FT

Answer 6

increases

Question 7

Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.

Answer 7

2.5 to 5

Question 8

In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.

Answer 8

5-11

Question 9

The stress developed in a material without any permanent set is called the

Answer 9

elastic limit

Question 10

In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the

Answer 10

shortest centre to centre distance between adjacent tubes.

Question 11

Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe-Thiele’s method?

Answer 11

Reflux is not a saturated liquid

Question 12

Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi)

Answer 12

η = 17 - 61.1 log μ

Question 13

In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cm.

Answer 13

10

Question 14

Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate

Answer 14

8

Question 15

To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of

Answer 15

(1.2)^(5/3)

Question 16

In a heat exchanger, shell side fluid velocity can be changed by changing the tube

Answer 16

layout and pitch

Question 17

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

Answer 17

At the inner surface.

Question 18

It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than

Answer 18

0.80

Question 19

Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger

Answer 19

permits the use of more tubes in a given shell diameter.

Question 20

Bracket supports are the most suitable for supporting __________ vessels.

Answer 20

thin-walled vertical

Question 21

Two iron pipes of the same nominal diameter but different schedule numbers will have the same

Answer 21

inside diameter (should be OD)

Question 22

Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C.

Answer 22

7500

Question 23

Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about __________ percent.

Answer 23

20

Question 24

In chemical process equipment, the conical bottom heads used, usually has an apex angle of

Answer 24

60°

Question 25

Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than __________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop.

Answer 25

75

Question 26

Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is

Answer 26

less

Question 27

Correct use of ‘factor of safety’ is very important in equipment design. It is defined as the ratio of the

Answer 27

ultimate stress to working stress.

Question 28

The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about __________ mm of water column per meter height of packing.

Answer 28

20-40

Question 29

__________ tray arrangement is recommended for distillation column having diameter up to 4 ft.

Answer 29

Cross-flow

Question 30

What is the value of ‘q’ for saturated liquid feed to a distillation column?

Answer 30

1

Question 31

The main purpose of providing stepping on the trays is to

Answer 31

facilitate handling of large flow rate of liquid.

Question 32

The operating pressure drop range in a bag filter is about __________ mm water gauge.

Answer 32

50-150

Question 33

The ends of a cylinderical vessel can be closed by a head, which can be one of the four shapes. For the same thickness, choose the one which can withstand the highest pressure.

Answer 33

Ellipsoidal

Question 34

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

Answer 34

Di,opt = 3 Q^(0.36) ρ^(0.18)

Question 35

Wall thickness of schedule 40 pipe as compared to that of schedule 80 pipe is

Answer 35

less

Question 36

Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm.

Answer 36

0.1 to 2

Question 37

A stuffing box is used for

Answer 37

prevention of fluid leakage around moving parts.

Question 38

Pressure drop (Δp) and the superficial gas mass velocity (G) in case of packed absorption tower operating in the preloading range are related as

Answer 38

Δp = G^2