Process Equipment and Plant Design

181. Longitudinal stress induced in a thin walled cylindrical storage vessel is

1. pD/2t
2. pD/4t
3. pD/3t
4. pD/6t

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182. 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).

1. 250
2. 450
3. 650
4. 750

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183. Lug support is meant for supporting _________ vessels.

1. Large horizontal cylindrical
2. Tall but empty
3. Small
4. Thick walled tall

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184. Maximum acceptable total liquid gradient over a tray is about _________ mm.

1. 5.5
2. 12.5
3. 30.5
4. 45.5

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185. Maximum allowable vapour velocity in a bubble cap tower is determined by the

1. Entrainment considerations
2. Vapour density
3. Diameter of the column
4. None of these

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186. Maximum plate efficiency is achieved in case of _________ flow.

1. Split
2. Cross
3. Cascade
4. Reverse

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187. Maximum size of the raschig rings used in a packed tower is about _________ of the column diameter.

1. 1/10th
2. 1/20th
3. 1/30th
4. 1/50th

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188. Mc Cable Thiele method used for finding theoretical stages in a distillation column assumes that the

1. Sensible heat differences are small, because the temperature changes from tray to tray is small
2. Trouton's rule is applicable
3. Liquid/vapor loading across the column remains constant
4. All (A), (B) and (C)

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189. Minimum baffle spacing recommended in a shell and tube heat exchanger is equal to

1. 5 cms
2. 40% of the I.D. of the shell
3. 25 cms
4. I.D. of the shell

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190. Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)

1. 0.2 D
2. 0.5 D
3. 0.66 D
4. 0.80 D

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