Section 8

Question 1

Power required for agitation depends upon the

Answer 1

all

Question 2

Tube height in a calendria type evaporator is normally less than __________ metres.

Answer 2

2

Question 3

Pick out the wrong statement.

Lug supports are less expensive than other type of supports.

A pipe is differentiated from a tube by the fact that a pipe has a greater wall thickness compared to the tube.

A reducer is used to change the direction of a pipe in a straight run.

The method of fixing tubes to a tube sheet by expanding is called ‘tube rolling’.

Answer 3

A reducer is used to change the direction of a pipe in a straight run.

Question 4

For a 25 mm hole drilled in plates to be rivetted, the shank diameter of the rivet should be __________ mm.

Answer 4

23

Question 5

Optimum economic pipe diameter for fluid flow is determined by the

Answer 5

total cost considerations (pumping cost plus fixed cost of the pipe).

Question 6

Pressure differential maintained across a continuous rotary vacuum filter is in the range of __________ mm Hg column.

Answer 6

250 to 500

Question 7

Vertical storage vessels are never supported by __________ support.

Answer 7

saddle

Question 8

In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be

Answer 8

more than that for fluid flow.

Question 9

Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, σ = yield strength and E = modulus of elasticity)

Answer 9

σ/E

Question 10

In a pressure vessel containing multiple openings of various dimensions at different parts, stress concentration at the edges of the opening is maximum which becomes negligibly small beyond the area covered by __________ times the hole diameter.

Answer 10

two

Question 11

What is the slope of the feed line, if the feed to a distillation column is a saturated liquid ?

Answer 11

infinity

Question 12

Filtration rate is affected by the

Answer 12

all

Question 13

Liquid gradient over a tray can be minimised by

Answer 13

all

Question 14

In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes

Answer 14

can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less.

Question 15

Le/D for 90° elbow (medium radius) and 90°square elbow would be respectively around

Answer 15

25 and 60

Question 16

__________ heat exchanger is also known as ‘hair pin type’ exchanger,

Answer 16

Double pipe

Question 17

What is the value of ‘q’ for saturated vapor feed to a distillation column ?(where q = fraction of the feed stream that is liquid.)

Answer 17

0

Question 18

In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around

Answer 18

1.5

Question 19

Frame thickness in the plate and frame filter press is normally in the range of __________ inches.

Answer 19

0.25 to 8

Question 20

Cylinderical shell thickness of rotary drier is generally __________ mm.

Answer 20

6-8

Question 21

The ratio of lateral strain to linear strain is termed as the

Answer 21

The ratio of lateral strain to linear strain is termed as the

Question 22

The distance between the centre of a rivet hole to the nearest edge of the plate is called

Answer 22

margin

Question 23

Mc Cable Thiele method used for finding theoretical stages in a distillation column assumes that the

Answer 23

all

Question 24

A minimum clearance of about __________ mm is maintained between the distillation column wall and the bubble cap.

Answer 24

38

Question 25

Pick out the wrong statement.

If sufficient residence time (around 8 seconds) is not proivided to the downcoming liquid in the downcomer, it may entrain some vapour.

The liquid head in the downcomer should not be greater than one half the plate spacing to avoid flooding.

The dischare end of the downcomer must project far enough into the tray liquid so that no gas bubbles can enter the open end and by pass the bubble caps.

none of these.

Answer 25

none of these

Question 26

Pick out the wrong statement pertaining to shell and tube heat exchanger.

Clearance between shell & baffles and between tube & baffles should be
minimum to avoid by-passing of the fluid, but it should be enough to permit the removal of tube bundle.

Baffles are supported independently of the tubes by tie rods and positioned by spacers.

Tie rods are fixed at one end in the tube sheet by making blind holes and the minimum number of tie rods is 4 with at least 10 mm diameter.

Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.

Answer 26

Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.

Question 27

Wind load consideration in the design of a support can be neglected, when the vessel is

Answer 27

short (< 2 m) and housed indoor.

Question 28

Souders Brown equation given by, U = Kv sqrt ((pl-pv)/pv) is used for the calculation of the __________ in a continuous distillation column.

Answer 28

diameter of the bubble cap column

Question 29

The ratio of volumes of the mixed reactor to the plug flow reactor (for identical feed composition, flow rate, conversion, and for all positive reaction orders) is always

Answer 29

> 1

Question 30

Le/D for a Tee (used as elbow, entering run) would be around

Answer 30

60

Question 31

Tubes are fixed to the tube sheet (a thick circular metallic plate) by the method of tube rolling and brazing (non-removable) or ferrule connection (removable). Thickness of the tube, sheet is normally __________ the outside diameter of the tube but in no case it should be less than 22 mm (7/8”).

Answer 31

equal to

Question 32

A shell may by termed as thin if its thickness to diameter ratio is less than 0.1. The factor which can be neglected in the calculation of membrane stresses is

Answer 32

bending

Question 33

Scale up problem in design based on the similarity concept takes into account __________ similarity.

Answer 33

all

Question 34

__________ closure is the weakest enclosure for cylindrical vessels.

Answer 34

Conical or flat plate

Question 35

Which of the following efficiencies can be greater than 100% ?

Answer 35

Murphree plate efficiency.