My machine is SIEMENS Gas turbine V94.3A (Dry Low Nox Combustor) which operate by natural gas. The gas turbine use premix flame as main fuel and use pilot flame for increase the flame stability and i found the problem as follows:

I found high combustor acceleration value around 2.5 - 3 g. when GT is loading or unloading at % IGV opening around 20-30% and this problem will run away when GT is operate out of %IGV range 20-30%.

How to solve this problem.
Thank alot for any help.
GTEGAT

 

It is difficult to tell what the problem is at your site from this information. Humming during loading and unloading is a common problem on V94.3A machines.

'Normally' these accelerations can be tuned away by making small changes to the pilot gas curve. To do this, you need much more information regarding the accelerations (frequency analysis, operating conditions,...).

I do not advise to tune this problem on your own. It probably will create more problems than you will solve. It is better to contact your OEM for this.

If you have more detailed data I can take a (brief) look at the problem. (GT.comb [at] gmail [dot] com )

 

Thank alot about your suggestion.

This problem was solved by OEM in Feb'09, but now the problem still occur. At that time the OEM try to increase the pilot mass flow at IGV% 20-30%. They try to change the pilot mass flow many time but the combustion humming was not better.

So i want to know which data you want to get for analyze such as applitude and frequency of humming and combustion acceleration. please let me know i will sent them to you immediately.

thank you very much,
GTEGAT

 

Hi
1. you may check the humming frequency at the problem (in the range 20 - 30 % IGV) because the frequency indicates the source of the problem.

2. does the problem occur in the summer like the winter or not?

3. if you working with ARGUS system for combustion dynamics monitoring send the data and trends of the problem (with ambient temp. and relative humidity and load)

 

Your GT should have low frequency humming (10-30Hz).

If it is the case you should check if the pilot percentage is more than 10%.

For a correct pilot percentage the LHV should be considered.