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US 6,199,364 B1Granted
Burner and process for operating gas turbines with minimal NOx emissions
AssigneeAlzeta Corporation
InventorsRobert M. Kendall, Steven J. Greenberg
Life of this patent
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AssigneeAlzeta Corporation
InventorsRobert M. Kendall, Steven J. Greenberg
Estimating the term…
A porous, low-conductivity material formed of metal or ceramic fibers provides the burner face of a gaseous fuel combustor for gas turbines capable of minimizing nitrogen oxides (NOx) emissions in the combustion product gases. A preferred burner face, when fired at atmospheric pressure, yields radiant surface combustion with interspersed areas of blue flame combustion. A rigid but porous mat of sintered metal fibers with interspersed bands of perforations is illustrative of a preferred burner face that can be fired at pressures exceeding 3 atmospheres at the rate of at least about 500,000 BTU/her/sf/atm. By controlling the excess air admixed with the fuel in the range of about 40% to 150% to maintain an adiabatic flame temperature in the range of about 2600° F. to 3300° F., the NOx emissions are suppressed to 5 ppm and even below 2 ppm. At all times, carbon monoxide and unburned hydrocarbons emissions do not exceed 10 ppm, combined.
The improved combustion method for gas turbines to suppress the formation of air pollutants, which comprises passing gaseous fuel and admixed compressed air through a porous fiber burner face having areas that, when fired at atmospheric pressure, yield surface combustion and interspersed areas of higher porosity that yield blue flame combustion, firing said fuel and admixed air in a compact combustion zone adjacent said burner face and confined by a metal liner with multiple openings, said firing being conducted at a pressure in the range of about 3 to 20 atmospheres and at a rate of at least about 500,000 BTU/hr/sf/atm, passing cooling compressed air along said liner with some of said compressed air flowing through said openings to merge with gases of said combustion zone, and controlling said admixed air to provide an excess in the range of about 40% to 150% to maintain an adiabatic flame temperature in the range of 2600° F. To 3300° F., thus producing combustion gases containing not more than 5 ppm NOx and not more than 10 ppm CO and UHC, combined.
The method of operating a high-pressure burner for gas turbines to suppress the formation of combustion air pollutants, which comprises passing gaseous fuel and admixed compressed air through a porous fiber burner face having dual porosities that, when fired at atmospheric pressure, yield radiant surface combustion interspersed with blue flame combustion, firing said fuel and admixed air and confining combustion in a compact combustion zone adjacent said burner face with a metal liner adapted for enhanced cooling, said firing being conducted at a pressure of at least about 3 atmospheres and at a rate of at least about 500,000 BTU/hr/sf/atm, passing cooling compressed air along said liner to effect cooling thereof, and controlling said admixed air to provide an excess in the range of about 40% to 150% to maintain an adiabatic flame temperature in the range of 2600° F. to 3300° F., thus producing combustion gases containing not more than 5 ppm NOx and not more than 10 ppm CO and UHC, combined.
The improved method of suppressing the formation of combustion air pollutants in the operation of a gas turbine that has a rotary compressor and a turbine on a common axis, which comprises passing compressed air from said compressor at a pressure of at least about 3 atmospheres and admixed gaseous fuel through a porous fiber burner face that is sufficiently perforated to ensure a pressure drop therethrough of less than 3% and to produce a multiplicity of blue flames when fired at atmospheric pressure, firing said admixed fuel and compressed air in a compact combustion zone adjacent said burner face and confined by a metal liner with multiple openings, said firing being conducted at a rate of at least about 500,000 BTU/hr/sf/atm, passing compressed air from said compressor along said liner with some of said compressed air flowing through said openings to merge with gases of said combustion zone, and proportioning said admixed fuel and compressed air to provide about 40% to 150% excess air to maintain an adiabatic flame temperature in the range of about 2600° F. to 3300° F. and thus to produce combustion gases containing not more than 5 ppm NOx and not more than 10 ppm CO and UHC, combined.
Dependencies are inferred from the claim text.