Tube wall thickness depends on the cor-rosiveness of the fluids and their operat

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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.
Options
A. 16
B. 19
C. 28
D. 38

Correct Answer

2. Weep holes provided in the plates of a distillation column
Options
A. facilitate draining out liquid from a tray when the unit is not in operation.
B. are normally located near the overflow weir so that any delivery of liquid during operation follows approximately the same path as the overflow fluid.
C. must be large enough (usually 1/4" to 5/8" dia) to prevent plugging but should not deliver excessive amount of fluid during operation.
D. all (a), (b) and (c).

3. If 'D' is the inside diameter of the shell of a shell and tube heat exchanger, then the baffle spacing is usually in the range of
Options
A. D/2 or minimum 2" to 5D.
B. D/5 or minimum 2" to 5D.
C. D/5 or minimum 2" to D.
D. none of these.

4. 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
Options
A. increases
B. decreases
C. remains same
D. may increase or decrease depending upon the solubility of the gas in the liquid

6. In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the
Options
A. liquid gradient on the tray.
B. lower skirt clearance.
C. lower static submergence.
D. small downcomer liquid seal.

8. Low pressure steam (with saturation temperature between 105 to 120�C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer).
Options
A. 250
B. 450
C. 650
D. 750

9. High pressure fluid in a shell and tube heat exchanger should preferably be routed through the
Options
A. tubes to avoid the expansion of high pressure shell construction.
B. shell side for smaller total pressure drop.
C. shell side, if the flow is counter-current and tube side if the flow is co-current.
D. shell side for large overall heat transfer co-efficient.

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