fractionation vacuum tower overhead
fractionation vacuum tower overhead
(OP)
Hi,
i am looking for overhead-line's design criteria,
the goes from vacuum tower (0.45 bara) to condenser.
tx
i am looking for overhead-line's design criteria,
the goes from vacuum tower (0.45 bara) to condenser.
tx





RE: fractionation vacuum tower overhead
The upper limit is fluid velocity. Gas lines in continuous service should not employ velocities above 15-20 m/sec. For wet steam, reduce that to half of the value.
Dejan IVANOVIC
Process Engineer, MSChE
RE: fractionation vacuum tower overhead
Going up to 30m/sec on corrosion resistant alloy ( CRA) piping would be possible, subject to pressure drop permissible for the operation of the ejectors at the condensors. Use isothermal compressible flow expressions for dp calcs on these lines, if dp > 10% of column top exit nozzle pressure in absolute units ( kpa abs or psia abs)
RE: fractionation vacuum tower overhead
"
dp/100 < 0.035*P^1/2 where P is the pressure of top reciver drum
AND
v < min(100/(dens^1/2); 60-80 ft/s)
"
What do you think about?
RE: fractionation vacuum tower overhead
Look at what vacuum you need inside the column for the most conservative case, start with the design overhead flow and add some 10-20% margin on top of that, and size the overhead line accordingly. That way you can't do wrong.
Dejan IVANOVIC
Process Engineer, MSChE