Methods of reducing emissions for a sequential combustion gas turbine and combustor for a gas turbine

1. A method for reducing emissions and/or improving safety in a Sequential enVironmental (SEV) combustor of a sequential combustion gas turbine, the SEV combustor having a mixing region for mixing hot gases with a fuel, a combustion region downstream of the mixing region, and a wall between the mixing region and the combustion region with a portion forming a combustion front panel orientated generally perpendicular to the flow of the hot gases through the SEV combustor, the method comprising:

combusting an air/fuel mixture in a first combustor to produce said hot gases;

subsequently introducing the hot gases into the SEV combustor for further combustion;

introducing steam into the mixing region of the SEV combustor; and

cooling the combustion front panel with steam.

2. A method according to claim 1 , wherein the SEV combustor includes a burner wall, and further comprising:

cooling the burner wall with steam.

3. A method according to claim 1 , wherein the SEV combustor includes a lance which projects into the mixing region for introducing the fuel, and further comprising:

cooling the lance with steam.

4. A method according to claim 1 , wherein the SEV combustor includes a lance which projects into the mixing region for introducing the fuel, and wherein introducing steam further comprises introducing steam through the lance.

5. A method according to claim 1 , wherein the SEV combustor includes a wall, and wherein introducing steam comprising introducing steam through the wall.

6. A method according to claim 1 , further comprising, between said combusting and said subsequently introducing:

introducing said hot gases into a gas turbine; and

wherein said subsequently introducing comprises introducing said gas gases from said gas turbine.

7. A method according to claim 6 , wherein said gas turbine is a first gas turbine, and further comprising, after said cooling:

introducing hot gases from said SEV combustor into a second gas turbine.

8. A method according to claim 1 , in which said combustion front panel includes steam cooling passages extending therethrough, said step of cooling the combustion front panel with steam further comprising:

convectively cooling said combustion front panel, including passing said steam through said steam cooling passages in said combustion front panel.

9. A Sequential enVironmental (SEV) combustor useful with a sequential combustion gas turbine, in which sequential combustion gas turbine an air/fuel mixture is combusted in a first burner and the hot gases are subsequently introduced into the SEV combustor for further combustion, the SEV combustor comprising:

a chamber having a chamber wall defining a mixing portion configured and arranged to mix the hot gases with a fuel, and a combustion region downstream of the mixing portion;

at least one inlet configured and arranged to introduce the hot gases into the mixing region;

at least one inlet configured and arranged to introduce a fuel into the mixing region;

at least one inlet configured and arranged to introduce steam into the mixing region;

wherein the chamber wall comprises a portion between the mixing portion and the combustion region orientated generally perpendicular to the flow of the hot gases through the SEV combustor and forms a combustion front panel having a steam cooling passage or holes configured and arranged to cool the combustion front panel with steam; and

a steam source in fluid communication with the steam cooling passage or holes.

10. The SEV combustor according to claim 9 , wherein at least one of the at least one inlet configured and arranged to introduce steam into the mixing region is positioned in the chamber wall.

11. The SEV combustor according to claim 9 , further comprising:

a lance which projects into the mixing region, configured and arranged to introduce fuel into the mixing region;

wherein the at least one inlet for introducing steam into the mixing region is positioned on the lance.

12. The SEV combustor according to claim 9 , further comprising:

a lance which projects into the mixing region, configured and arranged to introduce fuel into the mixing region; and

a cooling passage formed in the lance configured and arranged to cool the lance with steam.

13. The SEV combustor according to claim 9 , further comprising:

a cooling passage in or adjacent to a portion of the chamber wall, the cooling passage configured and arranged to supply steam to cool the chamber wall.

14. The SEV combustor according to claim 9 , further comprising:

said hot gases, in the at least one inlet configured and arranged to introduce the hot gases into the mixing region;

said fuel, in the at least one inlet configured and arranged to introduce a fuel into the mixing region; and

said steam, in the at least one inlet configured and arranged to introduce steam into the mixing region.

15. A sequential combustion gas turbine comprising:

a first combustor;

a gas turbine fluidly downstream of said first combustor, configured and arranged to receive combustion products from said first combustor to drive said gas turbine; and

a second combustor fluidly downstream of said gas turbine, configured and arranged to receive working fluid from said gas turbine, wherein said second combustor is an SEV combustor according to claim 9 .

16. A sequential combustion gas turbine according to claim 15 , wherein said gas turbine is a first gas turbine, and further comprising:

a second gas turbine fluidly downstream of said second combustor, configured and arranged to receive combustion products from said second combustor to drive said second gas turbine.