1 reply to this topic

[nsr.kn85@gmail.com]

Hi All,

 

We have two compressor stations on our Gas pipeline. They are required to blowdown gas after 48hrs of a shutdown.

 

As per the shutdown logic, the Vent valve remains open while the inlet valve, loading (Pressurization) valve and outlet valve remains closed.

 

The Natural gas is released to the atmosphere through a cold flare stack.

 

With each start-up we are purging the piping with natural gas as per the logic. my assumption for this logic is that the piping is at atmospheric pressure after blowdown and is susceptible to air ingress.  

 

My question is, why don't we keep the Blowdown valve closed after a shutdown with a 10-20 kPag pressure inside the piping to avoid air ingress and it will eliminate the requirement for purging on each start-up (if my assumption is correct)?. If there has been any maintenance done and the piping is exposed to atmosphere then we can enable the purging sequence?

 

Secondly, is there a standard or recommended practice which explains the condition which makes purging mandatory?

regards,

 

[MaryHarri]

Hello there. Obviously, it is not preferred much, but a small tip, I must say as a user. I try to do the cleaning with 100% pure water. Maybe it can work for you.