gas liquid separator design/ sizing 2

[curious2kno]

I need to quickly size a separator to knock out fine liquid droplets (carry over) from process organic vapor stream, using centrifugal or other mechanisms. Normally this involves detailed design including fixed internals, but due to time constraints, have to do a crude design quickly to meet process needs (in a day or so). This will be a pressure vessel. Vendors that specialize Separators have been contacted but they have long lead times, which I do not have that luxury at this moment. Any helpful tips?
I have looked at some answers on knock out drum area.

 

[siretb]

For a quick sizing , and for a vertical liquid separator
you can do a preliminary design by calculating the max velocity in the Knock Out drum so as

U(ft/s) < K(sqrt((rhol-rhov)/rhov)))

K=EXP(A + BX + CX^2 + D X^3 + E X^4 + F X^5
(I do not like much the polynomial, but for a quick job that will do)
A=-1.943 B=-0.8149 C=-0.1794 D=-0.01128 E=0.00036824
F=0.0002596
X=Ln((Wl/Wg * sqrt(rhol/rhog) Wl and Wg are liquid mass flow rate and Vapor massflowrate entering the drum

Units for rhol, rhog, Wl, Wg are irrelevant, as long as they are consistent.

The equation given is from Carl Branan's book.

 

[Yuze]

V=C1*((Dl-Dg)/Dg)^0.5
V - Critical vapor velocity used to specify maximum vapor velocity through the separate drum
C1 - Empirical constant = 0.157 ft/s (0.048 m/s)
Dl - liquid density
Dg - Vapor density.

The area used for calculating the velocity for the vertical drum is the section area above the high high liquid level.

The velocity of the vapor through the demist pad is at least 100%V. A lower velocity may result in a lower demist efficiency as the velocity may not be enough for liguid impingement

 

[mbeychok]

curioustokno:

Read this article in the Citizendium online encyclopedia:

Souders-Brown equation

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[EmmanuelTop]

You can also download the IPS standard at:

http://www.mop.ir/standard/ips/pr/e-pr-880.pdf

http://antwrp.gsfc.nasa.gov/apod/astropix.html

 

[maddocks]

With respect to Yuze, the factor of 0.157 is quite low and may result in an oversized separator (not that that's a bad thing). We normally use a factor of 0.35 with pressure corrections from the GPSA data book.

The separation section within GPSA is quite good. Other references include Evans, and Campbell.