Process Equipment and Plant Design
Pressure drop due to pipe fittings can be estimated by the equation, ΔP/p = 4f.Le/D.V2/2gc, 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
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
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
Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features
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
EXAMIANS