Process Equipment and Plant Design

Question 1

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

Answer 1

2.5 to 5

Question 1

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

Answer 1

elastic limit

Question 2

A rivetted joint does not fail by __________ of rivets.

Answer 2

none of these

Question 3

In a multipass shell and tube heat exchanger, the shell side cross flow area does not depend upon

Answer 3

none of these

Question 4

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 4

20

Question 5

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 metre height of packing.

Answer 5

20 - 40

Question 6

Pick out the wrong statement pertaining to the design of the bubble cap tray of a distillation column to give stable operation and even vapour distribution.

Answer 6

none of these

Question 7

With increase in gas flow rate to fabric surface area ratio (Nm3/hr/m2 fabric surface area), the size & the cost of a bag filter

Answer 7

decreases

Question 8

A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to the

Answer 8

central dished section and corner torus section.

Question 9

In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.

Answer 9

5-8

Question 10

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter )

Answer 10

0.2D

Question 11

Speed of industrial paddle agitator ranges from __________ rpm.

Answer 11

20 to 100

Question 12

The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is

Answer 12

infinity

Question 13

Multiple blade paddle agitator is used for mixing high viscosity liquids/paste in which the paddle diameter is commonly 0.8 times the tank diameter. However, the width of the blade is in the range of __________ times the paddle diameter.

Answer 13

0.1 to 0.25

Question 14

Floating head heat exchangers are used for the

Answer 14

cases where temperature difference between the shell and the tubes is more (>50°C).

Question 15

In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds.

Answer 15

8

Question 16

Length to diameter ratio of most rotary driers is in the range of

Answer 16

4 to 10

Question 17

Tube wall thickness depends on the cor-rosiveness of the fluids and their operating pressure & temperature and is specified by Birmingham wire gauge (B.W.G)-a number which varies from 8 to 18 with the numbers 14 and 16 being more commonly used. Outside diameter of tubes varies from about 15 to 50 mm; however a tube of less than __________ mm outside diameter is generally not recommended for fouling fluids.

Answer 17

19

Question 18

Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscoisty above __________ poise.

Answer 18

600

Question 19

In the design of a paddle agitator, the ratio is normally taken as

Answer 19

0.8

Question 20

The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress and the __________ stress.

Answer 20

damaging

Question 21

For annular flow of a fluid, the ratio of the equivalent diameter for pressure drop calculation to the equivalent diameter for heat transfer calculation is

Answer 21

d1/(d1 + d2)

Question 22

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

Answer 22

5

Question 23

At the following point for a given packing and set of fluids, the pressure drop per metre of packed height, with variation in fluid rates and operating pressure

Answer 23

remains same