Best solution for BIOGAS application

[AngelM]

Hello,

Can you tell me the best solution for the following application?

Fluid: BIOGAS
Temp: 20ºC
Pressure: 0,5 Bar
RPM: 2950
Shaft: 35mm

May be back to back double seal with a barrier fluid to lubricate the faces? Wich would be the appropiate barrier fluid considering we are talking about biogas?

 

[flexibox]

You can use a dual pressurized gas seal that uses N2 as the barrier fluid. This should be straight forward application . Google dry gas seals for pumps and you can read about them. In this arrangement N2 will contaminate the process with seal leakage.

Cheers

 

[AngelM]

Do you mean double seal with PLAN 53?

Is it a problem that the N2 contaminate the gas if a seal leakage is produced?
Why not to use a liquid as a barrier fluid?

 

[Airsporter1st]

Flexibox is referring to Plan 74. This is a dry gas seal using gas - usually nitrogen - as a barrier instead of liquid.

The advantages of this system is that you normally do not have to worry about the possible adverse effects of a fluid barrier leakage into the process.

If you want to use a dual pressurised seal with a liquid barrier then you need to decide upon the appropriate barrier fluid following the same principles as for any other application - i.e. the barrier fluid should be compatible with the process and with seal materials, it should have good lubricant properties, good specific heat properties, be cheap, easily available, non-hazardous in itself etc. etc. etc. See API 682 Section 8.5.5, for information on barrier fluid selection.

Alternatively, you could use a dry gas seal in either single or tandem configuration.