Questions and answers for exam Preparation

MCQs

Total Questions : 1628 | Page 158 of 163 pages

Question 1571. In case of design of a shell and tube heat exchanger,

Minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch
Minimum tube sheet thickness (in which tubes are fixed) is equal to the O.D. of the tube upto 15 mm tube diameter; and for > 15 mm tube diameter, tube sheet thickness is smaller than tube diameter
O.D. of the tube is 6 to 40 mm while the tube lengths used are 0.5, 2.5, 3.0, 4.0, 5.0, 6 metres
All of these

Discuss Question

Answer: Option D. -> All of these

Question 1572. In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres ρ = apparent solid density, kg/m³ L = flow rate of dry solids, kg/see. m² drier cross-section H = hold up of solid.)

Z.H.ρ/L
Z.H/L.ρ
H.ρ/L
L/Z.H.ρ

Discuss Question

Answer: Option A. -> Z.H.ρ/L

Question 1573. The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is

pd/4t
pd/8t
pd/2t
pd/t

Discuss Question

Answer: Option A. -> pd/4t

Question 1574. The most common standard size of bubble caps used in industrial operation is

6" dia cap with 4" dia riser
4" dia cap with 8" dia riser
8" dia cap with 1" dia riser
1" dia cap with 0.5" dia riser

Discuss Question

Answer: Option A. -> 6" dia cap with 4" dia riser

Question 1575. The circumferential (hoop) stress in a thin walled cylinderical vessel under internal pressure is

pd/3t
pd/t
pd/4t
pd/2t

Discuss Question

Answer: Option D. -> pd/2t

Question 1576. Pick out the wrong statement about routing of fluids in a shell and tube heat exchanger.

Lower flow rate fluid should be routed through the shell side
Higher pressure fluid stream should be routed through the shell side
The corrosive and fouling fluid should be preferably routed through the tubes
The viscous fluid should be routed through the shell side

Discuss Question

Answer: Option B. -> Higher pressure fluid stream should be routed through the shell side

Question 1577. Pick out the wrong statement pertaining to shell and tube heat exchanger.

Bracket supports are used for horizontal shell, while saddle support is used for vertical shell
Baffles are supported independently of the tubes by tie rods and positioned by spacers
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
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

Discuss Question

Answer: Option A. -> Bracket supports are used for horizontal shell, while saddle support is used for vertical shell

Question 1578. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer co-efficient (hi) vanishes after a Reynold number of

3000
5000
10000
1000

Discuss Question

Answer: Option C. -> 10000

Question 1579. Pick out the wrong statement pertaining to a shell and tube heat exchanger.

The maximum unsupported tube span is generally about 75 times tube diameter, but is reduced to about 60 times for aluminium, copper & alloys of these
Disk and doughnut baffle is the most commonly used baffle
The maximum value of baffle spacing is equal to the I.D. of the shell
The minimum value of baffle spacing is 50 mm

Discuss Question

Answer: Option B. -> Disk and doughnut baffle is the most commonly used baffle

Question 1580. In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for