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High spread problem of GE frame 5 gas turbine. We are operating GE frame 5 gas turbines model MS-5001P. Dual fuel nozzles are installed in turbine but we are operating our turbine on gas fuel. Recently we have removed the atomizing air compressor due to excessive seal leakage and after OEM consent we have installed welded plugs on fuel nozzles on atomizing, purge and liquid fuel passages to avoid back flow of combustion gases.
In recent combustion inspection we observed burning and erosion on nozzle cap portion (atomizing air passage). We have changed all fuel nozzles the installed nozzles leak and flow test were carried out before installation and found ok.
After combustion inspection exhaust spread was 17 OC at load of 9.0 MW. But spread changed to 27 OC when load increased to 13 MW. Now a day’s exhaust spread was in the range of 31-33 OC at same load of 13.0 MW. Following are the exhaust thermocouple readings at load of 12.8 MW<pre>
TT-XD-1 OC = 416
TT-XD-2 OC = 410
TT-XD-3 OC = 404
TT-XD-4 OC = 412
TT-XD-5 OC = 427
TT-XD-6 OC = 441
TT-XD-7 OC = 431
TT-XD-8 OC = 424
TT-XD-9OC = 413
TT-XD-10 OC = 415
TT-XD-11 OC = 412
TT-XD-12 OC = 428
Average exhaust temperature = 419
Change in spread = 32 OC
MARK-V allowable spread lie above 45 OC
Axial flow compressor discharge pressure = 7.51 kg/cm2
Axial flow compressor discharge temperature = 339 OC</pre>
Please suggest whether this change in spread is normal? If abnormal what the outcomes are if we will operate the turbine on this same spread of 31-33 OC?
As we are familiar that the by blinding of atomizing air passage cooling air was blocked in fuel nozzle but it can’t change the gas flow from gas tip of fuel nozzles to cause change or improper combustion.
[email protected]
In recent combustion inspection we observed burning and erosion on nozzle cap portion (atomizing air passage). We have changed all fuel nozzles the installed nozzles leak and flow test were carried out before installation and found ok.
After combustion inspection exhaust spread was 17 OC at load of 9.0 MW. But spread changed to 27 OC when load increased to 13 MW. Now a day’s exhaust spread was in the range of 31-33 OC at same load of 13.0 MW. Following are the exhaust thermocouple readings at load of 12.8 MW<pre>
TT-XD-1 OC = 416
TT-XD-2 OC = 410
TT-XD-3 OC = 404
TT-XD-4 OC = 412
TT-XD-5 OC = 427
TT-XD-6 OC = 441
TT-XD-7 OC = 431
TT-XD-8 OC = 424
TT-XD-9OC = 413
TT-XD-10 OC = 415
TT-XD-11 OC = 412
TT-XD-12 OC = 428
Average exhaust temperature = 419
Change in spread = 32 OC
MARK-V allowable spread lie above 45 OC
Axial flow compressor discharge pressure = 7.51 kg/cm2
Axial flow compressor discharge temperature = 339 OC</pre>
Please suggest whether this change in spread is normal? If abnormal what the outcomes are if we will operate the turbine on this same spread of 31-33 OC?
As we are familiar that the by blinding of atomizing air passage cooling air was blocked in fuel nozzle but it can’t change the gas flow from gas tip of fuel nozzles to cause change or improper combustion.
[email protected]
