Process Equipment and Plant Design
The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.
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
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
Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features
Plate tower is preferred over packed tower, if the operation involves liquids containing dispersed solids
Plate tower is perferred, if interstage cooling is required to remove heats of reaction or solution
In operations involving large temperature changes. (e.g. distillation), plate towers are preferred over packed towers as the packing may be crushed due to large temperature changes
The total weight of a dry plate tower is usually much more than that of a dry packed tower designed for the same duty
EXAMIANS