Condensate in Instrument Gas on Off-Shore Platform

The key to extracting moisture from any gas is to lower the temperature of the gas below the dew point.Try installing a refrigerated dryer at the common supply point before all instruments, and a condensate tank and timed blow off valve to rid the system of moisture and other condensates.

Make sure all taps to instruments come off of the supply line with a tee facing up, not directly down to the instrument.Elbow over, then down to the instrument and install a tee at the instrument supply tap, and continue down past the instrument to a blow off valve at the end of the line below the instrument.Also install a blow off at the end of the main supply line and check regularly.

Blow off the lines every day to start, and adjust according frequency to need. ( More often in cold weather)

Do not use galvanized pipe, because the zinc can become dislodged and clog orifices in your instruments.Use copper,aluminum,stainless, or even black pipe instead.

If water vapor is your only concern, a bubble glass filled with glycerin will absorb the remaining moisture.Not sure how your hydrocarbons would react with the glycerin, though.The glycerin method only applies to air.Everything else above applies to any gas.Of course, you are well aware of all the safety precautions dealing with a flammable gas:Explosion proof fixtures, etc.

Good luck

EZStreet

Thanks Guest for your reply. Based on your description, do you have any drawings for easier understanding?

Would really appreciate.

It's difficult to pinpoint the source of your problem without specific information. However, in general, you should have a moisture specification for your instrument gas and you should monitor the gas moisture level to determine when and why it exceeds the specification. The dryers may have functioned correctly when installed but may now be saturated and currently ineffective. Also, dryers have a maximum flow rate. If your usage exceeds the max flow rate, the gas will not be dried to your specification. All pipes and tubing should be metal because moisture will diffuse through organic tubing. We could go on, but without knowing the ballpark dew point you require, much additional information is likely overkill.

Hi Welderman,

Thanks for your reply.