System and method for increasing the responsiveness of a duct fired, combined cycle, power generation plant
View Patent ↗A system and method for increasing the responsiveness of a duct fired, combined cycle power generation plant ( 12 ) via operating one or more gas turbine engines ( 14 ) at a part load condition less than 100 percent load, one or more steam turbine engines ( 16 ), and one or more supplemental burners ( 18 ) providing additional heat to a heat recovery steam generator ( 20 ) upstream from the steam turbine engine ( 16 ) is disclosed. The combination of the steam turbine engines ( 16 ) and supplemental burners ( 18 ) operating together with gas turbine engines ( 14 ) at a part load condition enables the system to quickly change output to accommodate changes in output demand of the duct fired, combined cycle power generation plant ( 12 ). By operating the one or more gas turbine engines ( 14 ) at a part load condition, the gas turbine engines ( 14 ) are able to be used to increase net output of the combined cycle power generation plant ( 12 ) faster than relying on increasing output via duct firing.
1. A method for increasing the responsiveness of a duct fired, combined cycle power generation plant, characterized in that:
operating at least one gas turbine engine at a part load condition less than 100 percent load;
operating at least one steam turbine engine via steam created at least in part from heat generated by the at least one gas turbine engine;
firing at least one supplemental burner to provide additional heat to a heat recovery steam generator upstream from the at least one steam turbine engine such that combined output of the at least one gas turbine engine at part load and the at least one steam turbine engine with additional steam input generated by firing the at least one supplemental burner upstream of the heat recovery steam generator upstream is at least as great as operating the at least one gas turbine engine at 100 percent load condition and the at least one steam turbine engine at 100 percent load condition; and
controlling the at least one gas turbine engine to change output of the at least one gas turbine engine to accommodate changes in output demand of the duct fired, combined cycle power generation plant,
wherein the step of firing at least one supplemental burner to provide additional heat to a heat recovery steam generator upstream comprises firing at least one supplemental burner during a startup process in which the at least one gas turbine engine starts operating to enable the heat recovery steam generator to warm up faster and allow excess steam to be provided to gland seals and a condenser.
2. The method of claim 1 , characterized in that controlling the at least one gas turbine engine to change output of the at least one gas turbine engine to accommodate changes in output demand comprises increasing output of the at least one gas turbine engine to increase output of the duct fired, combined cycle power generation plant to accommodate an increase in output demand.
3. The method of claim 2 , characterized in that increasing output of the duct fired, combined cycle power generation plant to accommodate an increase in output demand comprises increasing output of the duct fired, combined cycle power generation plant at a rate of at least five megawatts per minute.
4. The method of claim 2 , characterized in that increasing output of the duct fired, combined cycle power generation plant to accommodate an increase in output demand comprises increasing output of the duct fired, combined cycle power generation plant at a rate of at least ten megawatts per minute.
5. The method of claim 2 , characterized in that increasing output of the duct fired, combined cycle power generation plant to accommodate an increase in output demand comprises increasing output of the duct fired, combined cycle power generation plant at a rate of at least fifteen megawatts per minute.
6. The method of claim 1 , characterized in that operating at least one gas turbine engine at a part load condition less than 100 percent load comprises operating the at least one gas turbine engine at a part load condition less than 90 percent load.
7. The method of claim 1 , further characterized in that a ramp up process in which the at least one gas turbine engine is ramped up followed by an increase in output of the at least one supplemental burner.
8. The method of claim 1 , further characterized in that a ramp down process in which output of the at least one gas turbine engine is ramped down.
9. The method of claim 8 , characterized in that the ramp down process in which the output of the at least one gas turbine engine is ramped down is followed by a decrease in output of the at least one supplemental burner.