Burner for a gas turbine and method for feeding a gaseous fuel in a burner
View Patent ↗A burner ( 1 ) for a gas turbine includes a duct ( 2 ) enclosing a plurality of vortex generators ( 3 ) and, downstream of them, a lance ( 5 ) provided with nozzles ( 6 ) for injecting a gaseous fuel. The burner ( 1 ) also includes a mixer ( 7 ) for diluting and mixing the gaseous fuel with air to form a mixture. The mixer ( 7 ) is connected to the nozzles ( 6 ) for feeding them with the mixture. A method includes feeding the gaseous fuel in the burner ( 1 ).
1. A burner for a gas turbine, the burner comprising:
a duct enclosing a plurality of vortex generators;
a lance downstream of the plurality of vortex generators, the lance comprising nozzles configured and arranged to inject at least a gaseous fuel;
a mixer comprising a mixing device arranged within the lance, said mixer configured and arranged to dilute and mix said gaseous fuel with an oxidizer to form a mixture, said mixer being connected to said nozzles for feeding the nozzles with the mixture;
a mixing zone downstream of the lance; and
wherein said mixer is positioned outside said duct.
2. A burner as claimed in claim 1 , wherein the nozzles comprise first and second apertures, and wherein said lance comprises at least a first pipe connecting said mixer to the first aperture of the nozzles and at least a second pipe connecting a liquid fuel feeding to the second aperture of the nozzles.
3. A burner as claimed in claim 2 , wherein said first aperture of the nozzles and said second aperture of the nozzles are coaxial, and wherein the first aperture is annular and encircles the second aperture.
4. A burner as claimed in claim 2 , wherein the first pipe is annular and encircles the second pipe.
5. A burner as claimed in claim 1 , further comprising:
a by-pass parallel to the mixer.
6. A sequential gas turbine comprising:
first and second burners;
wherein the second burner is a burner as claimed in claim 1 ; and
wherein the oxidizer is air.
7. A burner as claimed in claim 1 , further comprising:
a source of gaseous fuel and a source of oxidizer;
wherein the mixer is in fluid communication with the source of gaseous fuel and with the source of oxidizer.
8. A method for feeding a gaseous fuel in a burner of a gas turbine, the method comprising:
providing a burner with a duct and a mixer according to claim 1 ;
mixing a gaseous fuel with an oxidizer to form a mixture outside of the duct of the burner;
feeding the mixture from the mixer to a nozzle; and
thereafter injecting the mixture in the duct into a hot gas flow for further mixing in the duct such that the mixture auto ignites.
9. A method according to claim 8 , wherein mixing comprises mixing said gaseous fuel with the oxidizer in a weight ratio that permits a prefixed temperature of the mixture to prevent auto ignition of the mixture within the lance to be obtained at injection.
10. A method according to claim 9 , wherein said weight ratio is 1:1.
11. A method according to claim 8 , wherein the oxidizer is air.