(A) 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

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

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

(D) Valve trays have the highest turn down ratio (i.

(E) the ratio of the highest to the lowest vapour flow rates) and thus provide the maximum flexible operating range