Page 371 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 6 .9 Gas Turbine Best Practices

Best
Best Practice 6.9Practice 6.9
Require condition monitoring features of the control following vendor maintenance cycles without the benefitof
system to include facilities for trending of air compressor extending these cycle times by the use of effective pre-
head and efficiency, gas generator and power turbine dictive maintenance techniques.
efficiency. Vendors now provide diagnostic services that will evaluate turbine
Complete predictive maintenance monitoring of gas turbines condition and recommend when maintenance is to be performed.
requires trends of compressor, gas generator and power turbine
performance to optimize run times between maintenance cycles. Benchmarks
The end users of ‘best of the best’ turbines optimize their gas This practice has been used since the 1990s, in which trending of air
turbine performance monitoring methodology to extend their run times compressor performance and engine efficiency is highly recom-
significantly beyond vendor’s recommendations (by as much as mended, when not provided by the vendor. Note: Compressor dis-
60,000 hours). charge pressure and temperature must be available for air compressor
Review vendor’s performance monitoring capabilities during the bid performance trending.
stage of the project and require complete performance monitoring
capabilities.
Lessons Learned
Failure to trend compressor, gas generator and power
turbine performance results in the practice of completely

B.P. 6.9. Supporting Material generator turbine and power turbine) as well as mechanical and
support system condition. We have included this material for
FAI has developed and used Excel spreadsheets that receive, reference.
calculate and trend gas turbine performance (air compressor, gas

Table 6.9.1 Spreadsheet for trending gas turbine performance

Client:

Equip #:

Date

Compressor Performance
P atmosphere (bara)
T ambient ( C)

P Disch. (bara)
T Disch. ( C)

Speed (RPM)
K
(K-1)/K e e e e e e e
(n-1)/n e e e e e e e

Polytropic Efficiency e e e e e e e
What Action is Required Based on
% Difference from Design Efficiency?

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