Process Equipment and Plant Design

201. Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the

1. Practical limit reached, due to low heat transfer rate because of inadequate temperature difference
2. Economic limit reached, when the plant cost exceeds the saving of steam
3. Both (A) & (B)
4. Neither (A) nor (B)

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202. Of the pressure vessels, with same thickness but different diameters, which one withstands higher pressure?

1. Larger dia vessel
2. Smaller dia vessel
3. Larger dia long vessel
4. Strength of the vessel is same irrespective of the diameter

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203. Optimum economic pipe diameter for fluid flow is determined by the

1. Viscosity of the fluid
2. Density of the fluid
3. Total cost considerations (pumping cost plus fixed cost of the pipe)
4. None of these

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204. Optimum reflux ratio in a continuous distillation column is determined by the

1. Maximum permissible vapour velocity
2. Flooding limit of the column
3. Total cost consideration (fixed cost of the column plus the cooling water & steam cost)
4. None of these

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205. Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where ε = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi)

1. η = 17 - 61.1 log μ
2. η = 24.6 (Δp/μ)
3. η = 1.66 - 0.25 log μ
4. η = 0.25 log μ - 1.67

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206. Overall mass transfer co-efficient in case of absorption of _________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling.

1. CO₂
2. SO₂
3. NH₃
4. None of these

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207. Overall tray efficiency of a distillation column is the ratio of the number of

1. Overall gas transfer units to the number of ideal trays required
2. Ideal trays required to the number of real trays required
3. Real trays required to the number of ideal trays required
4. None of these

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208. Pick out the correct statement

1. Centre to centre distance between two consecutives rivets in a row is called the pitch
2. A riveted joint made in overlapping plates is called butt joint
3. Hole size drilled in riveted plates is less than the actual size of the rivet
4. None of these

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209. Pick out the correct statement.

1. It is preferred to use a vertical condenser for condensation of vapor from a distillation column without sub-cooling
2. Draining of residual liquid on tray during shut down of distillation column is facilitated by weep holes
3. Random packing a packed tower offers the advantage of lower pressure drop and higher throughput of fluids as compared to regular/stacked packing
4. Risers are generally not connected to the plate in a distillation coloumn by bolts, rivets or welding

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210. Pick out the wrong statement

1. In a flanged and standard dished head, the crown radius is ≤ shell outside diameter
2. In a flanged and shallow dished head, the crown radius is > shell outside diameter
3. Flat head covers are most suitable for larger vessels operating at very high pressure
4. Flanged only head is a type of flat head in which gradual change in the shape at the centre results in reduced local stresses

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