Process Equipment and Plant Design

41. An adequate clearance between the tray and the shell wall of a distillation column is provided to

1. Drain the liquid from the tray when the unit is not in operation
2. Allow for thermal expansion and facilitate installation
3. Avoid back-trapping
4. None of these

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42. An increase in the liquid resistance to interphase mass transfer and a resultant reduction in plate efficiency is caused by

1. An increase in liquid viscosity
2. An increase in relative volatility for rectification columns
3. Decrease in gas solubility for absorbers
4. All (A), (B) and (C)

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43. An under-designed steam trap will

1. Waste steam
2. Destroy itself of acceleration wear due to rapid recycling
3. Back up condensate and cause water hammer in steam line
4. None of these

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44. Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscosity above _________ poise.

1. 300
2. 600
3. 1000
4. 1500

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45. Any shell opening greater than 5 cms for a storage tank must be reinforced for reason of

1. Preventing the local overstressing of the shell around the opening
2. Reduction of discontinuity in shape at the junction
3. Making the joint leak proof
4. None of these

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46. Apex angle of conical heads used in the bottom heads of chemical process equipments is usually

1. 30°
2. 45°
3. 60°
4. 75°

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47. At equal mass velocities, the values of film co-efficients for gases as compared to that for liquids are generally.

1. Higher
2. Lower
3. Same
4. Unpredictable

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48. 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

1. Increases
2. Decreases
3. Remain same
4. May increase or decrease depending upon the solubility of the gas in the liquid

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49. Back-trapping in a distillation column results due to

1. Low gas velocity
2. High gas velocity
3. Excessive liquid gradient over the tray
4. Low reflux ratio

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50. Baffle spacing is generally _________ the I.D. of the shell.

1. More than
2. Not greater than
3. Not less than one fifth of
4. Both (B) and (C)

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