Lubricating owing on cold service

[flexibox]

Need some advice on what to use to lubricate orings on an ethylene service at minus 160C. I was considering a smear of silicon oil, does anyone have experience in this field.
I know if silicon grease is used it turns into powder and can cause problems.

Thank you in advance.

 

[georgeverghese]

Saturated ethylene liquid / vapor at 1atm is at 170degK = -103degC, so what is this service for C2= requiring -160degC operation?

 

[flexibox]

I do not have the actual data sheets, in essence we are sealing cold services and wish to establish what to use to lubricate the orings. Do you have any experience?

 

[georgeverghese]

Sorry I dont, but at the outset, would have thought that in these cases, a dry gas seal would be the way to go- then the O ring wouldnt be exposed to these temperatures due the buffer seal gas between the process medium and the seal box?