Stoichiometric exhaust gas recirculation combustor with extraction port for cooling air

A method of operating a stoichiometric exhaust gas recovery turbine system, comprising:

• providing an extended flow sleeve about a firing zone of a combustor;
• providing a combustion liner comprising mixing zone and the firing zone,
• wherein the mixing zone is disposed about a fuel nozzle and the firing zone is disposed downstream of the fuel nozzle relative to a flow within the combustion liner;
• providing a casing radially outward of the extended flow sleeve;
• flowing ambient air along the extended flow sleeve about the firing zone to cool the firing zone;
• extracting a portion of the ambient airflow downstream of the firing zone by way of an extraction port disposed through the casing and in communication with the extended flow sleeve, wherein the extraction port is positioned axially aligned with the mixing zone and downstream of the firing zone relative to the ambient air path formed between the combustion liner and the extended flow sleeve, wherein the extended flow sleeve receives the flow of ambient air so as to cool the combustion liner about the firing zone and then the flow of ambient air splits into an extraction flow via the extraction port and a remaining portion flowing to the mixing zone within the combustion liner;
• flowing the remaining portion of the ambient portion of the ambient airflow into the firing zone for combustion therein;
• and
• providing a low oxygen recirculation flow to the combustor by way of a low oxygen recirculation inlet in communication with the mixing zone, wherein the low oxygen recirculation inlet is configured to provide the mixing zone with a low oxygen recirculation flow from the turbine to mix with the remaining portion of the ambient airflow within the mixing zone.

A stoichiometric exhaust gas recovery combustor for combusting a flow of ambient air and a flow of fuel, comprising:

• a fuel nozzle;
• a combustion liner comprising a mixing zone and a firing zone, wherein the mixing zone is disposed about the fuel nozzle and the firing zone is disposed downstream of the fuel nozzle relative to a flow within the combustion liner;
• an extended flow sleeve disposed about the combustion liner and in communication with the main compressor and the mixing zone;
• a casing disposed radially outward of the extended flow sleeve;
• an extraction port disposed through the casing and in communication with the extended flow sleeve and the turbine, wherein the extraction port is positioned axially aligned with the mixing zone and downstream of the firing zone relative to an ambient air path formed between the combustion liner and the extended flow sleeve, wherein the extended flow sleeve receives the flow of ambient air from the main compressor so as to cool the combustion liner about the firing zone and then the flow of ambient air spits into an extraction flow to the turbine via the extraction port and a combustion flow to the mixing zone within the combustion liner;
• and
• a low oxygen recirculation inlet in communication with the mixing zone, wherein the low oxygen recirculation inlet is configured to provide the mixing zone with a low oxygen recirculation flow from the turbine to mix with the combustion flow within the mixing zone.