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TRACERCO™ - Instruments

Prevention of Compressor Failure by Nucleonic Gauging

The use of nucleonic gauges – instruments, which utilize the unique properties of radioactive materials to provide, means of analysis, measurement and control – is widespread throughout the industry.

The importance of on-line measurement and control will of course be readily appreciated in the context of ensuring that the product conforms to requirements. TRACERCO™ Instruments have an important role in defect prevention as exemplified below;

Source containers

During the extraction of Hydrocarbon from the North Sea, the gas fraction has to be recovered and part of the re-injection into the oil for transportation by pipeline from the offshore well-head to the onshore terminal. On arrival on-shore, the gas is removed from the oil fraction and is recompressed for onward distribution. Failure of the gas compressor was a recurrent problem. The reason was fairly easy to identify. Prior to the gas compression stage, the oil was ‘knocked out’ in a separator vessel. Conditions inside the separator were extremely foamy and, if adequate level control was not maintained oil droplets or even slugs of oil, were carried forward with the gas to the compressor.

‘Conventional’ level gauges such as torque tubes or differential pressure gauges were unable to provide adequate control as there was a fluctuating interface between liquid and foam; there was also density variations in the foam layer itself. Tracerco was able to offer a viable solution with their range of TRACERCO™ Instruments based upon the gamma ray transmission method.

Nucleonic gauging

A TRACERCO™ Smart Level gauge was used to give an indication of the position of the interface between oil and foam while simultaneously a high level alarm, set to trigger at a density variation corresponding to foam intervening between source and detector, acted as a backstop in protecting the compressor from liquid carry-over. The entire system was installed and calibrated with the plant on-line and being completely non-invasive, offered a high degree of reliability. By preventing compressor failure, the nucleonic gauge facilitated continuous and efficient operation of the terminal. The savings associated with the prevention of this particular defect were not quantified but were clearly vastly in excess of the costs of the installed gauges.

TRACERCO™ Instruments, a range of permanently installed, non-contact instruments which are extremely low maintenance, are used when real-time measurements are required in difficult process fluids and operating conditions.

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