Industrial Gas Turbine 25MW

Designed and built to satisfy the need for heavy-duty equipment able to meet the requirements for low life-cycle cost, i.e. low first cost, low fuel costs and low costs for operation and maintenance.

The IGT-25 was initially designed as a mechanical drive in compressor and pumping applications, and was later adapted for power generation because of its robust design and its operating economy.

The turbine is delivered with a Dry Low Emission (DLE) combustion system as standard. A gas turbine with this system offers an additional advantage in maintaining low specific fuel consumption in all applications. The uncomplicated DLE-system does not add to the already low service costs for the IGT-25. The combination of using less fuel and generating fewer emissions makes the IGT-25 arguably the most environmentally friendly gas turbine in its power range. Industrial gas turbines from OTC offer long lifetime on oil platforms, in hot deserts, in arctic cold and in aggressive industrial environments. in other words, wherever the operating conditions are particularly tough. The IGT-25 has had a long history of successful operation in such environments and has already achieved some six million operating hours, with field experience constantly being fed back into the design for continuous improvement. OTC offers flexible maintenance solutions, enabling significant contribution to the plant operational profit arising from the optimization of preventive Maintenance planning.

Power Generation

(ISO) 24.77 MW(e)

Mechanical Drive

(ISO) 25.40 MW

General Specifications

Technical Specifications

– Mechanical drive: 25.40 MW

– Shaft efficiency: 33.5 %

– Heat rate: 10,258 kJ/kWh

– Turbine speed: 7,700 rpm

– Compressor pressure ratio: 14:1

– Exhaust gas flow: 83 kg/s

– Exhaust temperature: 543° C

NOx emissions (with DLE corrected to 15 % O2 dry) – Gas fuel : ≤ 25ppmV

– Liquid fuel : ≤ 42 ppmV (wet)

1- Axial Compressor:      

  • 10 stage axial flow compressor
  • 2 stages variable guide vanes
  • Electron-beam welded rotor

2- Combustion:                

  • 18 dual-fuel 2nd generation
  • Dry Low Emissions (DLE) burners
  • Welded annular sheet metal design

3- Compressor Turbine:  

  • 2-stage axial flow compressor turbine
  •  Both stages are air-cooled

4- Power Turbine:            

  • 2-stage free power turbine, uncooled
  • Electron-Beam Welded Rotor

5- Emissions control:       

  • DLE combustion system liquid fuel operation
  • Fuel System
  • Natural gas – Liquid fuel – Dual fuel
  • Combustion chamber by-pass system for part load operation emission control

6- Bearings:                      

  • Tilting pad radial and thrust bearings with Vibration and temperature monitoring

Flange-to-Flange Upgrade Scope

  • Unit rotors
  • Combustion system
  • Casings
  • Exhaust frame
  • Bearings
  • Bellmouth
  • Turbine Blades and Vanes
  • Compressor blades & Vane Segments
    • Upgrade options
  • Performance Upgrading (IGT-25 PC)
    • Mechanical drive: 27 MW
    • Shaft efficiency: 36 %
  • Maintenance Upgrading (IGT-25 MC)
    • 1.1 Life Time Extension in Hot Parts
  • Flexibility Upgrading
    • Integrated Control system
    • Fast Start/Loading Option
  • Improve reliability and extend maintenance intervals
  • Expand flexibility to operate in peak and cyclic environments
  • Lower fuel costs through reduced heat rate
  • Lower maintenance costs and extend asset/plant life
  • Recapture lost performance
  • Alleviate rotor end-of-life concerns
  • Reduce emissions

Package Specifications

Modular fluid systems incorporating:

  • Two main lube oil circuits
  • Low pressure and high pressure
  • 3×50% HP and 3×50% LP – AC drive
  • Lube oil pump with DC backup
  • Lubricating oil system
  • AC motor-driven auxiliary pump

Control system:

  • Siemens SIMATIC PLC-based with distributed control and processing capability installed on package
  • Optional Allen-Bradley system
  • Optional off-package systems

Fire and gas detection equipment

Fire suppression equipment

Combustion-air inlet-filtration options:

  • Pulse cleaning


  • Painted carbon steel or stainless steel
  • Noise level options (85 dB(A) standard)
  • Factory testing:
    • Core engine
    • Functional testing of modules as standard
    • Pre-commissioning of package
    • Optional core customer-witness test
    • Optional complete package test
    • Minimized customer interfaces

Power generation Performance

Mechanical Drive Performance


Direct drive – no output gearbox.

Specific heat input is drawn for base load, but is approximately correct for part load at corresponding speed/temperature.



Proper maintenance and operating practices

  • No need for special workshop maintenance
  • 24-hour gas generator exchange or Onsite maintenance
  • Modular build-up for easy maintenance on site
  • Standardized concepts for maintenance planning
  • Condition-based maintenance
  • Extended time between overhaul when running on part load
  • Low deterioration and service cost
  • Gas turbine can be removed on rollers through the maintenance doors
  • Horizontal split compressor casing