A. It is used for high viscosity liquor having large rate of scaling
B. The tube bundle is suspended on bracket
C. There is no central downtake
D. Downtake is formed by the annular space between the bundle and the shell
Related Mcqs:
- Pick out the wrong statement pertaining to the design of a horizontal tube evaporator ?
A. It is unsuitable for concentrating those liquids, which form a scale or deposit salt
B. It is suitable for process, in which the final product is a liquor instead of solid
C. Its usual dimensions are: tube dia = 2-3 cms; evaporator body dia = 1-4 metres and evaporator
height = 2.5-4 metres
D. Liquor flows inside the tube, while the steam is outside submerging the tube - Pick out the wrong statement pertaining to the design of a long tube vertical evaporator ?
A. Tube dia is 3-6 cms, while tube length in 3-6 metres
B. Steam is fed to the shell, whereas the liquor is filled inside the tube
C. Liquor level is maintained at 1/3rd to 1/2 of the height of the tube
D. None of these - Pick out the wrong statement pertaining to the design of the distillation column?
A. Generally, a skirt clearance of 0.5″ to 1.5′ is recommended to prevent plugging of the slots by
residue build up
B. The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles
C. If sufficient slot area is not provided, the gas may pass through the skirt clearance
D. None of these - Pick out the wrong statement pertaining to shell and tube heat exchanger_______________?
A. 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
B. Baffles are supported independently of the tubes by tie rods and positioned by spacers
C. 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
D. Bracket supports are used for horizontal shell, while saddle support is used for vertical shell - Pick out the wrong statement pertaining to a shell and tube heat exchanger ?
A. The minimum value of baffle spacing is 50 mm
B. The maximum value of baffle spacing is equal to the I.D. of the shell
C. 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
D. Disk and doughnut baffle is the most commonly used baffle - Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column ?
A. Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates
B. Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for sieve and valve trays than the bubble cap
C. Maintenance cost for valve and sieve trays are comparatively more than bubble cap tray due to their relatively complicated construction features
D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provide the maximum flexible operating range - Pick out the wrong statement pertaining to the comparative evaluation of performance of the packed tower and the plate tower ?
A. Plate tower is preferred, if interstage cooling is required to remove heats of reaction or
solution
B. Plate tower is preferred over packed tower, if the operation involves liquids containing
dispersed solids
C. The total weight of a dry plate tower is usually much more than that of a dry packed tower
designed for the same duty
D. In operations involving large temperature changes. (e.g. distillation), plate towers are
preferred over packed towers as the packing may be crushed due to large temperature changes - Pick out the wrong statement pertaining to ‘Horton sphere’ used for the storage of liquid ammonia ?
A. Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column
B. Thickness of spherical shell is half that of the cylindrical vessel under same operating pressure condition. Besides, the ratio of surface area to volume is less for sphere than any other shape; hence insulation required is less
C. Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2
D. Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 - Pick out the wrong statement about the design of sieve plate column and the bubble cap column ?
A. The downcomer design and the residence time in the downcomer is almost same for sieve
plate and bubble cap columns
B. Weir length for a bubble cap plate is the same as that for the sieve plate
C. Weir height for a bubble cap plate column is the same as that for a sieve plate column
D. Weir height in case of a bubble cap plate ranges from 50 to 150 mm and is higher than the
sieve plate - Pick out the wrong statement about the design of a sieve plate column ?
A. An increased weir height improves the tray efficiency at the cost of high plate pressure drop; optimum wear height being 40-90 mm for column pressure above atmospheric and 6-12 mm for vacuum columns
B. For segmental downcomers, the chord length is 60-80% of the column diameter. An initial value of downcomer area of 12% is taken in the design
C. Width of the calming section provided at the inlet and outlet sides of the plate is 75 mm for column diameter below 1.5 metres and 100 mm for larger diameter columns
D. Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds
