GE LM 2500 machines used for gas boosting. we have gas generator with axial flow compressor and HSPT connected. with that Exhaust Power Turbine will rotate coupled with gas compressor.

In this case gas generator we are using synthetic oil and gas compressor Mineral oil using.

What is the difference? why don't we use mineral oil for GAS Generator? Synthetic oil is high cost.

 

GE,

The gas generator of GE LM units is an aircraft engine, and most aircraft engines are built with bearings and components that require synthetic oil for proper lubrication and cooling.

The power turbine is NOT used on aircraft, and as such, the oil used for it does not have to be synthetic--which reduces the cost of the oil.

So, instead of thinking that the aircraft engine oil is expensive and if you had to use synthetic oil for both the gas generator and the power turbine your costs would be X, that you can use a less expensive oil for the power turbine and reduce your expenditure accordingly.

But, if you want to try using mineral oil in the gas generator, let us know how that works out for you. A lot of people would like to substitute mineral oil for synthetic oil in their aircraft-derivative turbines.