Burner for combustor with ammonia injection downstream of swozzle assembly and related method

A combustor for a gas turbine system, the combustor comprising:

• a combustor body having a combustion liner;
• a head end assembly having a cap assembly;
• and
• a plurality of burners positioned in the cap assembly and directed into the combustion liner, at least one burner of the plurality of burners including:
• an outer member;
• a center member inside the outer member and defining a fuel-air mixing passage therebetween;
• a swozzle assembly positioned in the fuel-air mixing passage, the swozzle assembly including a plurality of turning vanes configured to impart a swirl to an air flow flowing through the fuel-air mixing passage;
• and
• an ammonia injector system downstream of the swozzle assembly, the ammonia injector system configured to form an ammonia-air mixture for combustion in a combustion reaction zone in the combustion liner, the ammonia injector system including:
• a first plurality of ammonia injectors configured to inject a first ammonia flow into the air flow;
• and
• a controller configured to selectively control ammonia flow to the first plurality of ammonia injectors depending on a combustor load,
• wherein each of the first plurality of ammonia injectors has an injection axis aimed upstream from a radial position toward the air flow flowing through the fuel-air mixing passage downstream of the swozzle assembly.

A method of operating a combustor of a gas turbine system, the method comprising:

• in a combustor including a combustor body including a combustion liner;
• and a head end assembly including:
• a cap assembly, and a plurality of burners positioned in the cap assembly and directed into the combustion liner, at least one burner of the plurality of burners including a fuel-air mixing passage having a swozzle assembly including a plurality of turning vanes configured to impart a swirl to an air flow flowing through the fuel-air mixing passage, performing the following:
• injecting ammonia with a plurality of ammonia injectors aimed upstream into the air flow in the fuel-air mixing passage at one or more axial locations downstream of the swozzle assembly to generate an ammonia-air mixture;
• and
• combusting the ammonia-air mixture formed by the plurality of burners in a combustion reaction zone in the combustion liner.