We are trying to commission a Solar Mars 100 fitted with SoLoNox dual fuel system - currently running on diesel. The injectors were pulled at 12 hours due to suspected air leak indicated by poor T5 spread however the injectors appeared clean and the gaskets were changed out. We then ran to 49 hours including a 24hr load test at 9.7MW as this is all we could achieve from a promised 10.5MW - T5 setpoint was 743 degrees and we regularly exceeded this during transient load increase. As the T5 spread was still erratic we pulled all 14 injectors and we found massive carbon deposits within the body of the injectors, injector barrels burnt beyond repair, combustor entry chutes burnt and eroded and cooked turbines. Our vendor is trying to blame poor fuel quality however from experience it seems we are over fuelling and not getting enough air to keep a good flame pattern and prevent flame from entering burner body. The engine is now damaged beyond limits and requires a factory overhaul. Does anyone have any ideas? I think there may be a problem with our air assist system!

Combustion failure could be contributed to a number of factors. First, was the oil, fuel, water, air, quality within OEM specifications? If the fuel quality was in spec, that would eliminate what the vendor is trying to push back with. Good Combustion is based on ideal AIR/FUEL mixture.... did you take emissions data during the run? NOX, CO, 02 is usually whats needed to determine if combustion was either RICH or LEAN. The residual coking is a sign of high temp with unburnt fuel.... I would start with eliminating any variables that is easy to prove then go after the vendor for improper design or commissioning!.
good luck thanks

Confirming the quality of your fuel should be easy, and this should be done first.
The big thing to check here would be the guide vane min/max angle, and bleed valve min/max angle.(KF_BV_Srg_FGEN_NGP and associated KF's)(KF_GV_Srg_Sched_FGEN, and associated KF's) These should be set by the OEM during commisioning and not changed by anyone else. If this is new equipment, both of these should be powered by PECC electronic actuators. The min/max angle for both of these should be on the test report and engine data plate. Confirm these values with what is in the PLC logic. These are both electronically limited and this is where they are set.
I would also use the "Histrical data Analyser" on the HMI to view the actual angle they both had at the time. With the machine in T5 control, both of these values should be maxed out. (Fully closed bleed valve, Guide vane angle on limit).
You mention bad T5 spread. What is the spread like when the machine is cold? If the spread is still bad then it could be faulty probes, wiring, or Isothermal plate.
Hope this helps.