Gas Compressor Inlet Scrubber Sizing 3

[Cthornton]

I am fairly new to the gas compression field.

Can anyone recommend a software package to size (height, diameter, inlet, outlet etc..) inlet scrubbers for 5 - 30 psi suction pressures related to compression. I have been searching for a software package for awhile without any luck. If no software has been developed how are the vessels sized? Any help is greatly appreciated.

Thanks in advance for any help


Chad

 

[TD2K]

The GPSA Engineering Handbook has a good section on knock-out drum sizing. Perry's handbook of chemical engineers also has a section I believe.

 

[zdas04]

One caution, the GPSA and Perry's stuff is a bit weak in low pressure sizing. They will predict a larger volume flow rate at 5 psig than will really go through the nozzle. The error is probably 5-10%. I usually just add 20% to the required flow and see what nozzle size is required.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

 

[Montemayor]

Cthornton:

All the compressor suction separators as well as inter-stage liquid separators (I stopped counting after 20) that I've designed, specified, installed and operated were designed using the Souders-Brown relationship. I never had a bit of problem with the results and most of them are still operating, some more than 40 years laters.

For the maximum vapor velocity in int separator,which will set the drum's diameter, the equation is:

Vmax = (k) [ (dL - dV) / dV ] ^ 0.5
where:
Vmax = maximum allowable vapor velocity, ft/sec
dL = liquid density, lb/ft3
dV = vapor density, lb/ft3
k = will vary between approx. 0.40 to 0.20 (depending if you employ a demister internal pad)

I have always preferred not to employ any internals if I could get away with it. I usually use a K of 0.2 under those conditions and the result is conservative and it works.

Look in Ernie Ludwig's "Applied Process design for Chemical and Petrochemical plants", Vol. 1; chapter 4 for a detailed review and a table on K values.

Hope this helps.


Art Montemayor
Spring, TX