We have GE Mark V Frame6 DLN2 (Duel fuel) GT.

I have few questions.

1) While in premix steady state purging of primary fuel nozzles is fulfilled by CPD air (say 12bar approx). whereas Liquid fuel nozzle, Atomizing nozzle & Water injection nozzles are cooled by Purge air compressor discharge air (say 15 bar).

My question is why GE not preferred CPD air to purge Liquid fuel nozzle, Atomizing nozzle & Water injection nozzles like primary fuel nozzles?

I think we were spending unnecessarily money on auxiliary power consumption by running purge air compressor (110KW).

2) IBH used to avoid icing formation at IGV blades due to minimum opening of IGV during starting in cold climatic countries. In that case, my question is at 95% of nominal speed (14HS)only IBH will come into service meantime 0-95% of speed how Icing formation at IGV blades neglected.

3) At that time electrical drives changeover all stand by fans/pump will start first then the already running one will stop finally. But while doing TK fan changeover things will not happening like that ie., running fan stops first after sometime lag fan gets start command, what is the reason behind that?

Thanks & Regards
Johnplayers

 

A Frame 6 DLN2 Dual Fuel is a rare beast. Can you confirm this is correct ? Is this a 6B or 6F.

1) You need a positive pressure higher than CPD to ensure liquid fuel is kept out of all the piping and manifolds it should not be in. Kind of keeps the piping from going kaboom if there are other hot air leaks, and keeps the flame only in the combustors. The purge air to CPD ration should be about 1.4 for normal diesel and a little bit higher for crude or heavier liquid fuels.

2) Because at 95% the IGV are still at 57 degrees. There is sufficient air flow to prevent ice formation from occurring.

3) Both TK should both be running when the speed is greater than 95%. Normally one fan starts first and then the other. There is normally a short, 10 seconds, delay before the second pump starts. This is just to minimize the transient current. The TK are one of the largest sized motors on the unit.

 

> A Frame 6 DLN2 Dual Fuel is a rare beast. Can you confirm this is correct?
> Is this a 6B or 6F.

Dear moose,

Yes, I'm sure we have Frame6, DLN2 machine.

But up to 86% of corrected speed our machine IGV will be kept minimum angle only (27DGA). after that IGV will open 5.27DGA per every 1% increase in corrected speed up to 48DGA (If IBH enabled)/ 54DGA (If IBH disabled).