Height Required to Ensure Liquid Disengagement

[ChemEngSquirrel]

I'm sizing a vertical two phase separator (hydrocarbon gas / water). The vessel will not have a gas outlet mist eliminator.

What height should i allow above my vessel's max liquid level to ensure adequate liquid disengagement from the gas leaving the vessel's gas outlet?

Thanks.

 

[racookpe1978]

What's the hydrocarbon molecular weight?

 

[ChemEngSquirrel]

MW = 18

 

[25362]

Thread798-221287
also:
"A Working Guide to Process Equipment" by Lieberman and Lieberman, McGraw-Hill, chapter 26.

 

[ChemEngSquirrel]

To 25362,

Thanks for responding but...the linked thread does not discuss height above liquid for disengagement. The sizing equations simply define diameter. I'm already aware of the equations. The fact that they do not define height above the liquid level for liquid disengagement is my problem. Can my liquid level trip be 2 mm from the gas outlet as long as the diameter is ok?

 

[Latexman]

My company's design manual says about one tank diameter of disengaging height is the minimum.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[25362]

I think it is a general design procedure/rule that the vertical distance between the top of the inlet nozzle and the tangent line of the top head should be at least one vessel diameter.

 

[racookpe1978]

At only 18 MW, there is so little difference between the two that you should NOT go any less than the standard 1 diameter. More if you can justify it. (To exaggerate slightly, for example, if you were separating heavy petroleum residues and water, the water is so much lighter less would be carried up at the same temperature.)

 

[moltenmetal]

1 D is standard here too, to the top (high trip) liquid level.

We make use of Eaton separators a lot here. They're smaller than empty bed Souders-Brown separators, and work reliably without demister pads that might plug etc. They offer both cast units for use in lines, and larger fabricated stand-alone vessels. I forget the name of the original mfg that Eaton has eaten- it seems that Eaton, Tyco, Flowserve etc. are eating everyone these days.