Combustion control for producing low NO.sub.x emissions through use of flame spectroscopy
AssigneeGeneral Electric Company
InventorDale M. Brown
Life of this patent
Estimating the term…
Abstract
Combustion in a gas turbine is controlled through use of flame spectroscopy in order to achieve low NO.sub.x emissions in the exhaust. By detecting and monitoring the combustion flame in the turbine to determine intensity of ultraviolet spectral lines, and dynamically adjusting the fuel/air ratio of the fuel mixture such that this intensity remains below a predetermined level associated with a desired low level of NO.sub.x emissions, the engine produces significantly reduced NO.sub.x emissions in its exhaust but at a sufficiently high combustion flame temperature to avoid any undue risk of flame-out, thereby assuring stable, safe and reliable operation.
Claims22
Apparatus for detecting combustion flames and reducing nitrogen oxide (NO.sub.x) exhaust emissions resulting from combustion of a mixture of hydrocarbon fuel and air within a gas turbine without undue risk of flame-out comprising:
- means for detecting and measuring intensity of a band of ultraviolet spectral lines emanating from a combustion flame in said turbine;
- means for converting the measured intensity value of said predetermined band of ultraviolet spectral lines into a corresponding value of a turbine operating parameter, said parameter being either temperature of said flame or NO.sub.x concentration in said exhaust emissions;
- and
- means for dynamically adjusting the fuel/air mixture for said turbine such that the value of said turbine operating parameter remains below a predetermined limit.
Apparatus for detecting combustion flames and reducing nitrogen oxide (NO.sub.x) exhaust emissions resulting from combustion of a mixture of hydrocarbon fuel and air within a turbine engine without undue risk of flame-out, said turbine engine including:
- a combustion stage having an internal combustion region and an outer wall and further including a fuel manifold situated external to said outer wall;
- a vernier valve assembly including a vernier fuel valve and being mounted to an external surface of the outer wall for controllably varying the components of said mixture in response to a drive signal and for producing a position signal representing the size of the vernier fuel valve opening;
- and
- an optical window extending through said outer wall and providing optical communication with said internal combustion region, said window being situated to permit optical emission emanating from the base of a combustion flame in said combustion region to be detectable through said window;
- said apparatus comprising means for detecting and measuring intensity of a band of ultraviolet spectral lines emanating from the combustion flame, said measuring means being mounted external to said outer wall and oriented with respect to said window so as to detect said optical emission through said window;
- and
- circuit means responsive to said vernier valve assembly and to said measuring means for generating said drive signal so as to controllably vary the size of said vernier fuel valve opening in order to maintain the temperature of said combustion flame above a predetermined value.
A method of detecting combustion flames and reducing nitrogen oxide (NO.sub.x) exhaust emissions resulting from combustion of a mixture of hydrocarbon fuel and air within a gas turbine without undue risk of flame-out comprising:
- detecting and measuring intensity of a band of ultraviolet spectral lines emanating from a combustion flame in said turbine;
- converting the measured intensity value of said band of ultraviolet spectral lines into a corresponding value of a turbine operating parameter;
- and
- dynamically adjusting the fuel/air mixture for said turbine such that the value of said turbine operating parameter remains below a predetermined limit.
Dependencies are inferred from the claim text.