Can I know if we can start the gas turbine GE 9FA by using liquid fuel without any auxiliary equipment if we don't have the adequate gas fuel. I asked one of GE engineer who told me that it supposed to have an additional air compressor to supply enough air to the atomizing air compressor suction.

 

Shimy,

Hopefully, others who read these posts who have 9FAs with liquid fuel will tell us about the configurations at their site(s)!

The best way to know for certain is to review the P&IDs, the Control Specification document, and the sequencing or application code running in the Speedtronic turbine control panel to know what is or isn't possible with the turbine at your site. Because we can't see those documents, we can't know for sure.

I will say this: Most GE-design F-class heavy duty gas turbines have AC motor-driven Atomizing Air Compressors which are usually sized for full-load operation, and most operation below full-load as well. Since most of those AC motors run at a constant speed it would seem that there is more than enough atomizing air for starting. I've seen some solenoid-operated valves that recirculate AA compressor discharge at low speed operation back to the suction of the AA compressor, but that wasn't done on all dual-fuel F-class units I've worked on, either.

Now, having said that, GE does change designs over the years. And, now that Frame 9s are being engineered and built in Europe the designs change pretty quickly and can be very complicated, unnecessarily so.

If I were at your site with access to documents and sequencing/application code I would begin by looking in the Control Specification document, Section 5.01, Liquid Fuel, and see what it says there about permitted operation.

If I didn't find what I was looking for there, I would look at the sequencing/application code running in the Speedtronic turbine control panel to see if starting on liquid fuel is blocked. I can't say exactly how I would do that, because I've never seen a unit which could operate on liquid fuel that couldn't also be started on liquid fuel so blocking that operation would be pretty custom (one-off) and it would just be a review process.

I would surmise, though, that if starting on Liquid Fuel were not permitted that Liquid Fuel could not be selected when the unit was at zero speed prior to initiating a START. I might also expect the Liquid Fuel "button"/target might be invisible or greyed-out below the minimum speed or load at which it could be selected.

And, there's something that just occurred to me: What kind of liquid fuel are you talking about? I'm talking exclusively about distillate liquid fuel, also called "diesel" fuel, or HSD (High Speed Diesel or -Distillate), or #2, or LSD (Low Sulfur Diesel). I'm NOT referring to Naphtha or any other liquid fuel, including residual ("bunker", #6, etc.) liquid fuels. I don't even know if F-class units can run on Naphtha, especially if they have DLN combustors.

To sum up, if we're talking about distillate/diesel fuel I would be surprised if the unit were capable of operation on distillate/diesel fuel that it couldn't also be started on distillate/diesel fuel. But, I continue to be surprised--especially at designs and systems produced by GE's European operation (based in Belfort, France).

Hope this helps!

Please write back to let us know what you finally learn about the machine at your site--and what kind of liquid fuel you are referring to, also.