I want to know the fuel oil pressure to GE frame 9 gas turbine when the unit is running on fuel oil. How much pressure is developed by main fuel oil pump? Can we see this pressure at Flow divider?

 

Which Frame 9 GE-design heavy-duty gas turbine generator do you have: a 9E or a 9FA or a 9FB?

Most liquid fuel flow dividers have a pressure gage installed on top of what is referred to as a "selector switch", or "selector valve." There is a handle on the valve which can be manually rotated to different positions to read the inlet pressure to the high-pressure liquid fuel pump, the liquid fuel pressure to each of the combustors, and the pump discharge pressure.

But, most turbines do not have any kind of pressure transmitter to read any liquid fuel pressure, with the exception of liquid fuel forwarding pump discharge pressure (which is also high-pressure liquid fuel pump inlet
pressure, also called supply pressure).

 

We have Frame 9E gas turbine. Our flow divider gives a pressure reading of about 140psig at each selection point. I think flow divider should give pressure at each combustor, but 140psig is too low. It seems to be pressure at inlet to main fuel oil pump.

 

You are correct; 140 psig seems too low, especially if it's the same for all selector switch positions. Seems you have a mechanical problem with the selector valve mechanism.

By looking at the Liquid Fuel piping schematic or P&ID you can see the selector switch is the only way to check the fuel pressures at the combustion cans/fuel nozzles.

Could be a gauge problem, too.