Compressor station

Gases typically transported over long distances in this way include natural gas, methane, ethylene, hydrogen, ammonia and carbon dioxide.

While being transported through a pipeline the gas pressure gradually decreases due to frictional effects and needs to be periodically repressurized at intervals of about 40 to 100 miles (64 to 161 km).

The size of the station and the number of compressors (pumps) varies, based on the diameter of the pipe and the volume of gas to be moved.

Limiting the pressure ratio ensures that the temperature rise across the compressors is not high enough to require after-coolers to prevent damage to the pipeline protective coatings.

[6] An intelligent pig, travelling at the prevailing gas velocity, measures the wall thickness of the pipeline and identifies areas of corrosion or defects.