Aircraft engines are used as ‘gas generators’, i.e. as a source of hot, high velocity gas. This gas is then directed into a power turbine, which is placed close up to the exhaust of the gas generator. The power turbine drives the generator.
The main advantages of Aero-derivative Gas Turbines are:-
• Easy maintenance since the gas generator can be removed as a single, simple module. This can be achieved very quickly when compared with other systems.
• High power-to-weight ratio, which is very beneficial in an offshore situation.
• Can be easily designed for single lift modular installations.
• Easy to operate.
• They use the minimum of floor area.
The main disadvantages of Aero-derivative Gas Turbines are:-
• Relatively high costs of maintenance due to short running times between overhauls.
• Fuel economy is usually lower than other types of gas turbines.
• The gas generators are expensive to replace.
Aero-derivative generators are available in single unit form for power outputs from about 8 MW up to about 25 MW. These outputs fall conveniently into the typical power outputs required in the oil and gas production industry, such as those on offshore platforms.