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Gas Path Analysis Ltd specialises in developing
software applications for the performance monitoring of gas turbines,
process compressors and combined heat and power (CHP) systems. GPA technology solutions
are driven towards reducing Total Ownership Costs of gas turbines and compression systems.
| KEY OBJECTIVES:
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Performance monitoring provides warning of problems in advance and reduces
unscheduled shutdowns. |
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Optimisation of gas compression systems will result in lower fuel costs and
reduce green house gas emissions. |
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Gas compression modelling also determines the capacity of your compression
system with and without performance deterioration and helps
reduce CAPEX when increased capacity is required. |
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Proverbially, to be forewarned is to be forearmed and the aim of GPAL software
solutions. |
| GPAL SOFTWARE PRODUCTS:
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 XINSTn |
Detect changes in gas turbine fuel qaulity on-line using GPAL XINSTn |
| GAS TURBINE SIMULATORS |
GPAL launches Version 2 of their gas turbine simulators for better understanding of performance and operations of gas turbines. Version 2 includes detailed simulation of Turbine Inlet Cooling (TIC) technologies to augment/enhance the performance of industrial gas turbines. |
| COOPS |
Optimize the performance of Combined Heat and Power (CHP) plants. |
| XWASH |
Optimize your engine wash to minimize your lost revenue. |
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XPGT3 |
Gas Turbine Performance Monitoring and Diagnostics System. |
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XCOMB |
Gas Turbine Combustion Diagnostics System. |
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XCREEP |
Turbine Creep Life Cycle Analysis. |
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GASCOMP |
Benefits of Model based Analysis. |
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XEM |
Gas Turbine Emissions Monitoring. |
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RB211-22 |
Performance Monitoring of a Three Shaft Aero-Derived Gas Turbine RB211-22. |
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Optimise performance of your gas turbines.
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Figure 1. RB 211-24.
Where actual performance does not match the design performance, GPAL software
helps identify the reasons for the performance deviation.
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Fuel cost is a significant part of the life cycle cost of gas turbines. Often operators are unable to check the quality of
their fuel, namely whether the Lower Heating Value (LHV) is within specification. Lower LHV is due to poor fuel quality is
costing the gas turbine operators millions of dollars in increased fuel costs.
Now you can detect fuel quality changes on-line and therefore arrest such increases in fuel costs using GPALs XINST
monitoring product. This is achieved by pattern matching fault indices, which indicate faults in gas turbines and
measurements such as fuel flow errors.
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The objective of the system is to detect the onset of damage at engine
component level so as to arrest/reduce damage. Measured parameters are
compared with their expected values and their differences used to detect
changes in component characteristics. These changes or deviations are known
as Fault Indices.
The measured and derived engine parameters using gas path analysis techniques
when faults are present (actual performance) and when no faults are present
(design performance) are shown in Figure 1. Where the actual performance
does not match the design performance the question then arises as to what
is the cause of the performance deviation.
By calculation of the Fault Indices, the components that have suffered
damage are shown in Figure 2. XPGTn series is a powerful tool for predictive based maintenance
and applicable to all gas turbines.
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Figure 2.
Measured parameters are compared with their expected values and their differences
used to detect changes in component characteristics. By calculation of
the Fault Indices, the components that have suffered damage are shown.
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Monitoring the Exhaust Gas Temperature spread (EGT Spread) is a good
means of detecting combustion problems. However, current systems do not
give alarms on the expected EGT spread and profiles therefore often
missing the onset of damage resulting from combustion problems.
XCOMB overcomes this problem by not only plotting the actual spread
and profile but also displays the expected EGT spread and profile. Again,
Fault Indices are used which represent the deviation of the EGT spread
based on the actual and expected values. The Fault Index is used to generate alarms when it exceeds alarm levels. Therefore XCOMB is an essential part of any predictive maintenance system for gas turbines.
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Figure 3.
XCOMB display of EGT patterns. |
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The Turbine creep life used is dependent on many factors (e.g. power
output, ambient conditions and performance deterioration). Without proper
monitoring it is difficult to assess the actual creep life used.
XCREEP evaluates turbine creep life used based on actual operating conditions.
A significant increase in Mean Time between Overhauls (MTBO) can result
by monitoring the creep life on actual operating conditions.
The example (Figure 4) shows at least a threefold increase in MTBO by
monitoring the creep life actual operating conditions. The display from
XCREEP shows the actual life used when performance deterioration is present,
the life used based on fired hours and the life used if no performance
deterioration is present. The manufacturer’s estimated Creep Life is indicated
in the fired life line in Figure 4.
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Figure 4.
The display from XCREEP shows the actual life used when performance is
present, the life used based on fired hours and the life used if no performance
deterioration is present. |
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GasComp can model the steady state performance of any gas compression
system and also optimize fuel consumption for a specified gas production.
Gas Comp, together with Fault Indices and Creep Life Analysis, gives
rise to the concept of Production Based Maintenance and Predictive Based
Maintenance.
Figure 5 illustrates that after optimisation, the compressors are outside
recycle and over 7% reduction in fuel consumption is achieved.
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Figure 5.
Gas Comp display of compressor performance curves after optimisation. |
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Parametric Models
Many parametric models have been proposed and validated in predicting emissions.
However, these models often need engine measurements, which are difficult
or almost impossible to measure on an engine operating on a site. Such
measurements often refer to combustion air flow and combustion exit temperature
(turbine entry temperature). Gas path analysis techniques do derive these
measurements and use them in the computation of Fault Indices. Therefore
gas path analysis and parametric models offer a cost-effective solution
for determining gas turbine emissions
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The application of the XPGT3 to monitor the performance of a RB211-22
Gas Turbine.
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