Process Equipment and Plant Design
For a cylinderical vessel of moderate height, the weld joint efficiency for joints parallel to the cylinderical axis is given as 1.0, while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylinderical vessel, what value of weld joint efficiency should be used?
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
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
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
EXAMIANS