Distillation

Hello Mr. Lieberman – I met you at your course in Singapore in 2000. How can this be? I have a deprop. that has sieve trays. It worked very well. All we did was to change from 2 mm to 4 mm tray deck thickness because the trays were getting thin. Nothing else. Now, the tower will not produce on spec. LPG propane at the reflux rate used before turnaround. We must use 30% more reflux for same feed.

--Rao, Singapore


Rao – Your problem is low vapor delta P thru sieve holes. While the vapor velocity thru sieve holes is constant, the orifice factor decreases as the tray thickness increases. The effect is surprisingly large. Vapor delta P varies linearly with the orifice factor.

--Norm