GAS TURBINE HIGH SPREAD TRIP

Our frame#6B GT with breech loaded fuel nozzles tripping suddenly on high spread while in liquid service.Before the spread started raising unit was running normal with very minimal spread (spread#1 was around 15) at the time of spread no.6 nozzle pressure in selector valve was 7kg more than all other nozzles.No deposits or blockage is seen on the no.6 tubing with BI also No.6 fuel tubing replaced with new one from flowdivider outlet to fuel nozzle inlet but no improvement.
 
I would suggest that you either replace the fuel nozzle if you have a spare, or swap the nozzles from can #6 to another can and see if the problem moves with the nozzle or not.
Can this unit operate on another fuel? Or is it only designed to run on liquid fuel?
 
I would suggest that you either replace the fuel nozzle if you have a spare, or swap the nozzles from can #6 to another can and see if the problem moves with the nozzle or not.
Can this unit operate on another fuel? Or is it only designed to run on liquid fuel?
We had swapped fuel nozzle of no.6 with no.9 but problem remains same.We had gas fuel option also but GCV valve is having some issues hence trial with gas not possible.
 
Your answer is not clear. If you swapped nozzles with Can #6 and Can #9, did the problem follow the nozzle? Or stay with the can? If the problem stayed with the can, then I suggest doing what is needed to swap fuel lines at the flow divider from can #6 to another can to see if the issue may be with the flow divider.
 
Hi,

Liquid fuel system is very common to have such issues with High Exhaust temperature, Combustion troubles and High Spread. here is remedial action on issue.
-Check liquid fuel quality if its unloaded by trucks to your fuel tanks. mostly downside their sludge with fuel if quality of fuel is not Good.
-Check the Frequency of changing Fuel filter if there is LP skid and HP Skid. check the Filter microns if there is any changes made to avoid frequent change of fuel filers to save the cost.
-Before starting the unit Vent fuel system for proper air elimination if there is air with fuel it is one of reason for Spread increase and fuel system disturbance. Till Main Control Valve of Fuel Vent is required ask I&C control person to force the logic and open valves to allow fuel comes at the point. Do vent from Pump if this shaft driven pump.
-Start the unit with fire mode keep spark plug off and check all fuel nozzle pressure by this approach check valve have enough fuel to open and supply fuel at nozzle tip. if all Nozzle are reading same pressure than its normal if any of them is showing higher that nozzle need to be replaced.
-if there is an opportunity remove all nozzle there is small strainer on check valve replace or clean it to have a proper flow of fuel.
-If Nozzle issue is not persisted check Atomizing air pressure it could be low or high. if its low open suction vent to provide more air flow and have proper air fuel atomization for proper burning.
-Check Spark plugs visually at least both of them should work due to liquid fuel. check flame detectors as well for their proper functionality.
- If all of them is check still issue is their Exhaust thermocouple which is reading higher for combustion chamber required to be checked and tested.

This remedial action should be checked and let us know if you can find solution with it.


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