The Compressor Train and Its Systems
How the driver, compressor, scrubbers, coolers, controls and auxiliaries work together as one train.
11 min
Activities: 0 of 2
More than one machine
A gas compressor never works alone. It is the centre of a compressor train: a driver to turn it, often a gearbox, suction scrubbers to remove liquid, coolers to remove heat, an anti-surge or capacity control system, a lube oil system, a seal system, and a protection system that can trip the whole train. A failure in any of these stops the compressor, and on many sites a stopped compressor means stopped production or flaring.
This course treats the train as one system. Good operators and technicians understand how a change in one part, such as a fouled cooler, shows up somewhere else, such as a surge trip.
Parts of a typical train
Worked example 1: a cooler that tripped a compressor
An air-cooled intercooler on a two-stage compressor had dirty fins. On a hot afternoon its outlet temperature rose by 15 °C. Hotter gas entered the second stage, its discharge temperature rose, and the gas volume increased. The second stage moved towards surge, and the anti-surge valve opened more and more. Finally the high discharge temperature trip shut down the train. The fault was a cleaning task on the cooler, not a problem in the compressor.
Worked example 2: a scrubber level controller
A suction scrubber drain valve stuck closed. Liquid rose in the scrubber until the high-high level trip shut the compressor. The trip did its job: without it, liquid would have entered the cylinders.
Match the part to its job
- Suction scrubber
- Intercooler
- Gearbox
- Anti-surge valve
- Trip system
A compressor trips on high second-stage discharge temperature on hot afternoons. Where should you look first?