| 1. | 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 η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi)
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| a. | A |
| b. | B |
| c. | C |
| d. | D |
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Answer: (a).A
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| 2. | For laminar flow (Nʀₑ < 2100) in steel pipe, the optimum inside pipe diameter is given by
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| a. | A |
| b. | B |
| c. | C |
| d. | D |
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Answer: (a).A
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| 3. | For annular flow of a fluid, the ratio of the equivalent diameter for pressure drop calculation to the equivalent diameter for heat transfer calculation is
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| a. | A |
| b. | B |
| c. | C |
| d. | D |
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Answer: (a).A
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| 4. | Pressure drop due to pipe fittings can be estimated by the following equation, where, Lₑ = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of Lₑ/D (dimensionless) for 45° elbow and 180° close return bends would be respectively around
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| a. | 5 and 10 |
| b. | 45 and 75 |
| c. | 180 and 300 |
| d. | 300 and 500 |
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Answer: (b).45 and 75
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| 5. | In a rotary drier, the average retention time of solid is (where Z = length of the drier, metres ρ = apparent solid density, kg/m³ L = flow rate of dry solids, kg/see. m² drier cross-section H = hold up of solid.)
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| a. | A |
| b. | B |
| c. | C |
| d. | D |
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Answer: (a).A
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