Petro-SIM Production - Gas Turbines

Petro-SIM Production includes unique detailed rating models of operating single and twin shaft (aero-derivative) industrial gas turbines, allowing you to model power and production balances and undertake full facility optimization. The object represents the compressor, fuel combustion chamber and turbines - one in single shaft units and two in twin shaft units, solving the system simultaneously to meet your specification.


The gas turbine considers two operation cases during solution: a Design case used to calculate design flowrates and efficiencies, and the actual case representing off-design or part-load performance. The design parameters required by Petro-SIM are:

  • Gas Turbine Base Load Rating at ISO (International Standards Association) conditions
  • Heat Rate at Base Load
  • Compressor Pressure Ratio
  • Exhaust Temperature at Base Load

These parameters can be obtained for most gas turbines from the Gas Turbine World Handbook, which is published annually. For the design case model, air is taken to be at ISO conditions of 15C, 1 atm and 60% relative humidity whilst the fuel is taken to be pure Methane at 15C by default. To base the design GT on a known performance on site, user defined air and fuel streams can be used instead of the internal ISO streams.

Actual performance is calculated using the air and fuel compositions and conditions you specify to meet one of six specifications you set:

  • Power - this is the actual turbine power, specified either through the attached energy stream or through the Gas Turbine unit operation itself
  • Load with respect to Design Power - this sets actual GT Power relative to the Design Power
  • Load with respect to Inlet Conditions - For 100% load, the off design performance will be calculated for the gas turbine with respect to the current operating conditions of the actual air, fuel and injection/extraction streams. This full load at the current operating conditions may be different from the full load at design conditions.
  • Turbine Inlet Temperature - this is the temperature at the combustion chamber exit. The turbine inlet temperature corresponding to 100% load is calculated by the object. You can specify a lower value if you want to set a part load duty without varying the inlet guide vane angle.
  • LHV Duty - the LHV duty can be used to specify part load operation without varying the inlet guide vane angle.
  • Fuel Flow - the Fuel flowrate can also be used to specify part load operation without varying the inlet guide vane angle.

By default, the gas turbine will be set to operate at 100% Load with respect to Inlet Conditions. With part load operations on single shaft turbines, the solution tries to maintain the maximum turbine inlet temperature (which maximises the part load efficiency) by adjusting the inlet guide vane angle. Once it hits the minimum angle allowed, the solution will switch to lowering Turbine Inlet Temperature by using less fuel.

Twin shaft units are generally variable flow, variable speed engines so it is possible to reduce air flow without the same limitations on inlet guide vane as single shaft gas turbines. Hence the solution will vary are flow and turbine inlet temperature as required to meet the specified load.