Process Equipment and Plant Design

81. For a cylindrical vessel of moderate height, the weld joint efficiency for joints parallel to the cylindrical axis is given as 1.0; while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylindrical vessel, what value of weld joint efficiency should be used?

1. 0.8
2. 0.9
3. 1
4. (0.8)0.5

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82. For a given design of bubble cap, the number of bubble caps to be used per tray is set by the

1. Allowable gas velocity through the slots
2. Plate spacing
3. Diameter of the column
4. All (A), (B) and (C)

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83. For a given fluid, as the pipe diameter increases, the pumping cost

1. Decreases
2. Increases
3. Remain unaffected
4. May increase or decrease depending upon whether the fluid is Newtonian or non-Newtonian

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84. 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

1. d₁/(d₁ + D₂)
2. D₂/(d₁ + D₂)
3. (d₁ + D₂)/d₁
4. (d₁ + D₂)/D₂

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85. For given number of passes, pitch & tube diameter, the maximum number of tubes that can be accommodated in a shell of tripled inside diameter will be _________ times.

1. About 9
2. Considerably more than 9
3. Considerably less than 9
4. About 3

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86. For high pressure process equipments/vessels, the connected nozzle should be

1. Welded
2. Screwed
3. Flanged
4. Brazed

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87. For identical operating conditions, the pressure drop over _________ tray is the highest out of the following.

1. Sieve
2. Valve
3. Counter flow
4. Bubble cap

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88. For identical situation, condensing film coefficient in case of a horizontal condenser is almost _________ the value expected in case of vertical condenser.

1. Half
2. Twice
3. Thrice
4. Five times

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89. For laminar flow (N_Re < 2100) in steel pipe, the optimum inside pipe diameter is given by

1. D_{i, opt} = 3 Q^0.36 ρ^0.18
2. D_{i, opt} = 3.9 Q^0.45 ρ^0.23
3. D_{i, opt} = 7.6 Q^0.36 ρ^0.9
4. D_{i, opt} = 3 Q^0.36 ρ1.86 μ^0.08

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90. For pipe flows, head is proportional to _________ at constant capacity (where D = pipe diameter).

1. 1/D
2. 1/D₂
3. 1/D5
4. D₂

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