Process Gas Leakage to Sour Seal Oil Trap

[bk19702]

Hello,

I'm currently conducting a cost evaluation of some existing centrifugal compressor seal oil systems in plant. I am curious as to the amount of usable process gas that is lost across the inner labyrinth seal on either end to the sour seal oil trap. Two machines in particular have no external buffer gas injected in this area; it would be strictly the process gas leakage across the inner laby (laby between the oil film seal and process). Would a simple bushing flow calculation using the inner laby dimensions/clearances suffice? Has anyone used a different method to approximate a leakage rate in these circumstances? Thanks for your help.

 

[rzrbk]

If it is like the ones I'm used to, your seal oil trap should have a restriction orifice on its vent that will limit the gas loss. There should be little or no pressure drop across the inner laby and the trap will run at suction/seal pressure.