In Gas Compression
Gas from a pure natural gas wellhead might have sufficient pressure to feed directly into a pipeline transport system.
Gas from separators has generally lost so much pressure that it must be re compressed to be transported.
Turbine compressors gain their energy by using up a small proportion of the natural gas that they compress.
The turbine itself serves to operate a centrifugal compressor, which contains a type of fan that compresses and pumps the natural gas through the pipeline.
Compressors are driven by gas turbines or electrical motors (for lower power also reciprocating engines, steam turbines are sometimes used if thermal energy is available). Often several stages in the same train are driven by the same motor or turbine. Gas turbine speed control response is relatively slow and even electrical motors are not fast enough since the surge response must be in the 100 mS range.If the compressor is turbine driven, a dedicated speed governor handles the fuel valves and other controls on the turbine to maintain efficiency and control rotational speed.
In Condition monitoring
Condition monitoring of machinery is generally used for large rotating apparatus, such as turbines, compressors, generators and large pumps.
Input devices are vibration meters, temperature (bearing, exhaust gases etc.) as well as number of start/stops, running time, lubrication intervals and over-current trips.These values are logged and compared with reference values to detect abnormal conditions and indicate when preventive maintenance is required or an equipment fault occurs (i.e.maintenance triggers)
Maintenance support functionality will plan maintenance based on input from condition monitoring systems and a periodic maintenance plant.
This will allow the system to schedule personnel for such tasks as lubrication or cleaning, and plan larger tasks such as turbine and compressor periodic maintenance.
In Power Generation and Distribution
The power generation system on a large facility is usually several gas turbines diving electric generators, 20-40 MW each.
If exhaust heat is not needed in the main process, it can be used to drive exhaust steam turbines (so called dual cycle) for additional efficiency.
Large rotating equipment and the generators are driven by gas turbines or large drives.
Gas turbines for oil and gas duty are generally modified aviation turbines in the 10-25 MW range. These require quite extensive maintenance and have a relatively low overall efficiency (20-27% depending on application).
Also, while the turbine is relatively small and light, it will usually require large and heavy support equipment such as large gears, air coolers/filters, exhaust units, sound damping and lubrication units.
