PROCESS EQUIPMENT AND PLANT DESIGN QUIZ

Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features

Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the bubble cap

Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates

Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range

Smaller sizes of pipe

High pressure throttling service

Very large diameter pipes

Very accurate flow control

Increases very rapidly

Decreases very rapidly

Remains constant

Increases linearly

3.5

1.75

2.5

1.25

10 to 15

5 to 10

1.5 to 2

2.5 to 5

D/2 or minimum 2" to 5D

D/5 or minimum 2" to D

None of these

D/5 or minimum 2" to 5D

43834

43832

4

2

Results in higher pressure drop per tray

Neither A nor B

Leads to high tray efficiency

Both A & B

Torispherical

Conical or flat plate

Hemispherical

Elliptical

5 and 10

45 and 75

300 and 500

180 and 300