| Case Studies
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;
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.
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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