Sizing Natural Gas Separators

[ppiboss]

We are a manufacturer of Pressure Vessels and typically build to customer specifications. Recently, we have been getting request to build equipment to a specific gas flow (i.e. 70 mmscfd, vert., 8" I/O, 1440 psi). Is there books, charts etc. to give us the correct diameter/length of a vertical 2 ph separator with a mist pad?

 

[MortenA]

Yes - but if you are building the vessel - you should be avare of the responsibility you are takking upon yourselft this way.

Normally i guess you would receivie an ordre for a vessel with a given size, internal etc.

Some campanies (e.g. Shell) have company standards that the insists that you follow no matter what.

Look out for GPSA or API for stadard calculations of this type (cant remember the exact stadard number but check their cataloug).

Best regards

Morten

 

[jay165]

Hire a process engineer to do the work. There are plenty of good ones who read this site and it sounds like they need a job.

 

[Scipio]

Agreed with jay165, I've awarded equipment to a few fabricators over the years who just hire on contractors for projects outside of their area of expertise for the duration of the design phase. That said, you'll also need more information on the gas & liquid properties to properly size that separator, like densities and expected flowrates. The calculation required to size the diameter on a vertical separator is basically intended to make sure the gas velocity upward is low enough to allow droplets of free liquid to fall out.

 

[Alph]

Have a look at
API 12J : Specification for Oil and Gas Separators

 

[KernOily]

"The calculation required to size the diameter on a vertical separator is basically intended to make sure the gas velocity upward is low enough to allow droplets of free liquid to fall out."

... and that is the crux of the biscuit. You must know the approximate droplet size of the entrained liquid phase. If you don't you have to make assumptions. Look in the GPSA book or API 12J, as someone suggested. - Pete

Thanks!
Pete