The solution to this problem is to shut off the gas purge and connect a nitrogen feed. This is a cheap solution as only small flows are required. The quantity of energy required for compressed air to produce nitrogen is less than gas lost in the compressor. So this is a win-win situation.
Airpack is supplier of complete (small) Nitrogen packages to improve the environment. The end result for gas companies is that they save on gas leakage, which means saving money but also improving their carbon footprint.