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Dear colleagues,
In our company we are currently operating a LM6000PC (with VIGV and no water injection) which has been loosing power during the last years. I am not involved directly in the operation of the GT, but I am interested on this issue and try to help my colleagues.
We have seen that from some years ago, power output has dropped progressively. To give an idea, at 15ºC the turbine power is around 30-32 MW. When new, the output is 42 MW.
The machine operates normally at T48 regulation mode.
Analyzing the data, during this time, I have noticed the following:
- performance decreases (same natural gas consumption for lower power output)
- pressure at HPC exhaust drops. it has dropped around 25% in total, which it is a lot.
- pressure at HPC inlet drops. it has dropped around 10% in total.
- temperature at HPC exhaust drops. it has dropped around 30% in total, which it is a lot.
- HP rotor speed has decreased around 10%
- pressure at LPC inlet remains stable at 1.1 bar.
- VBV has opened gradually from 1-2% till 15% in normal operation!
- VIGV has closed gradually, from 50% to 30%.
- VSV has closed gradually from 95% to 80%.
- air flow in the stack remains stable
Machine has been water-washed and HPC has been cleaned, without noticeable improvement.
My colleagues were claiming that most probably the filters are causing this situation, and we know they are dirty (dP and inspection). We did not find any air losses.
Do you think that poor filter conditions can generate such power loss? What other reasons could generate this situation?
If filters were really causing a big pressure drop, then pressure at LPC inlet would be low, and this it is not happening.
If pressure at LPC inlet is around 1 bar, why should the VBV open decreasing the flow?
Thanks for your help!
In our company we are currently operating a LM6000PC (with VIGV and no water injection) which has been loosing power during the last years. I am not involved directly in the operation of the GT, but I am interested on this issue and try to help my colleagues.
We have seen that from some years ago, power output has dropped progressively. To give an idea, at 15ºC the turbine power is around 30-32 MW. When new, the output is 42 MW.
The machine operates normally at T48 regulation mode.
Analyzing the data, during this time, I have noticed the following:
- performance decreases (same natural gas consumption for lower power output)
- pressure at HPC exhaust drops. it has dropped around 25% in total, which it is a lot.
- pressure at HPC inlet drops. it has dropped around 10% in total.
- temperature at HPC exhaust drops. it has dropped around 30% in total, which it is a lot.
- HP rotor speed has decreased around 10%
- pressure at LPC inlet remains stable at 1.1 bar.
- VBV has opened gradually from 1-2% till 15% in normal operation!
- VIGV has closed gradually, from 50% to 30%.
- VSV has closed gradually from 95% to 80%.
- air flow in the stack remains stable
Machine has been water-washed and HPC has been cleaned, without noticeable improvement.
My colleagues were claiming that most probably the filters are causing this situation, and we know they are dirty (dP and inspection). We did not find any air losses.
Do you think that poor filter conditions can generate such power loss? What other reasons could generate this situation?
If filters were really causing a big pressure drop, then pressure at LPC inlet would be low, and this it is not happening.
If pressure at LPC inlet is around 1 bar, why should the VBV open decreasing the flow?
Thanks for your help!
