hi,

Can we do to change the signal trip of HRSG Boiler from the shut down gas turbine signal to speed's gas turbine reach to 2850 rpm?

As you know, if gas turbine shutdown signal is activated, the HRSG boiler trip signal also is activated. but I want to change it from the beginning gas turbine shutdown signal activated to: if gas turbine speed reach to 2850 rpm then HRSG boiler trip. because may be problem exit to shut down the turbine solved before the gas turbine's speed reach to 2850 rpm.

please help me,
THANK YOU

 

abdi,

You have not provided much information. I am assuming the gas turbine is a GE Frame 9 (2850 rpm = 95% speed, the typical point of no return on a gas turbine shutdown). But, what is unknown is what the steam is used for. If it is a steam turbine, you have to be concerned with the steam temperature dropping as fuel to the gas turbine is reduced. And if there is supplemental firing, it would likely need to be tripped because the exhaust flow is being reduced.

Also, are there dampers (or a diverter damper) in the exhaust?
You would really also need to get the HRSG supplier involved, and probably the gas turbine supplier and the steam turbine supplier if applicable.

 

Hi,

The maximum speed for gas turbine frame 9 mark v is 3000 rpm.
In my company there is 8 GTG & HRSG Boiler and the boilers has the supplemental firing. the exhaust of gas turbine used for hrsg boiler after that steam used for many petrochemical company.

I know the exhaust gas flow is reduced but I think the lower of exhaust gas flow means the load of gas turbine is reduced. after that the load of steam is reduced as the load of gas turbine is reduced at normal condition.

Please Say to me the procedure of reduce the load of gas turbine when we want used in normal condition.

You said because the exhaust gas turbine reduced it must be the hrsg boiler trip. Why What happening for the boiler?

In my boiler HRSG there is a diverter Damper if the shut down gas turbine signal is activated the first time the supplemental burner of HRSG BOILER is trip after that the diverter damper of boiler close.

another question is how much time needs for reduce the speed's gas turbine from 3000 rpm to 2850 rpm if the load of gas turbine was 80 mw and the shutdown gas turbine signal is activated?

thank you.