Chemical Engineering Archives

4251. Pick out the wrong statement about the design of seive plate column and the bubble cap column.

The downcomer design and the residence time in the downcomer is almost same for seive plate and bubble cap columns.

Weir length for a bubble cap plate is the same as that for the seive plate.

Weir height for a bubble cap plate column is the same as that for a seive plate column.

Weir height in case of a bubble cap plate ranges from 50 to 150 mm and is higher than the seive plate.

✅ The correct answer is option C.

4252. Compensation against openings in process vessels for giving inlet and outlet connections, for providing sight glasses and manholes etc. is provided for strength and rigidity. The most efficient type of compensation is of __________ type.

nozzle or rim

flared out

fluid in

ring plate

✅ The correct answer is option A.

4253. Longitundinal stress induced in a thin walled cylindrical storage vessel is

✅ The correct answer is option B.

4254. The type of stress developed in a metallic bar on subjecting it to a change in temperature without allowing it to be deformed is __________ stress.

shear

tensile

compressive

thermal

✅ The correct answer is option D.

4255. 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

(1.2)3/2

(1.2)3/5

(1.2)2/3

(1.2)5/3

✅ The correct answer is option D.

4256. Length to diameter ratio of most rotary driers is in the range of

1 to 2

4 to 10

10 to 20

20 to 30

✅ The correct answer is option B.

4257. Normally, the length to diameter ratio of rotary dryers varies form 4 to 10 and for its economic operation, the number of transfer units (NTU) for such dryers varies from

1.5-2.5

3.5-5.5

7.5-10.0

Oct-15

✅ The correct answer is option A.

4258. Hazards associated with the relief valve leakage for extremely hazardous material storage can be taken care of by providing

rupture diaphragm

dikes

surge chamber

none of these

✅ The correct answer is option A.

4259. In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-10 times the column diameter, whichever is less. Maximum size of the pall rings should not exceed __________ of the column diameter.

1/10-1/15th

1/5-1/10th

1/20-1/30th

1/2 to 1/4th

✅ The correct answer is option A.

4260. A binary liquid azeotropic mixture has boiling point higher than either of the components, when it shows __________ deviation from Raoult’s Law.

positive

negative

none of these

✅ The correct answer is option B.