Field testing of gas turbine driven centrifugal compressor
units at operational production facilities can provide valuable
information about the condition of the equipment. In this
paper, a case study is presented based on field testing
performed on the compressors and gas turbine drivers of six
units at a gas compression station. Since the compression units
at this station are two sets of
three identical machines, this case
provides a unique opportunity to study both the advantages and
some of the challenges inherent in this type of testing. For the
compressors, comparisons are presented of the measured values
of head rise, required power, and thermodynamic efficiency.
For the gas turbines, performan
ce comparisons are presented in
terms of delivered power and heat rate. Calculations of the
effects of ambient temperature on
power and heat rate of the
gas turbines are also presented.
Some of the challenges of field
testing are addressed, with the
effects of fluctuations in gas
composition on the experimental uncertainty in the measured
performance treated in some de
tail. The topic of how field
testing can help to identify degradation of the capability of
compressors and gas turbines is also addressed. It is also
shown how models derived from the performance tests can be
used to forecast when fact
ors such as high ambient
temperatures and changes in the composition of the process gas
can create situations where the
compression units may not be
able to deliver the gas flow rates and pressure levels required
by the process.
