METHOD OF THERMAL NOX REDUCTION IN CATALYTIC COMBUSTION SYSTEMS

• Main Authors: VELASCO, MARCO, A, YEE, DAVID, K, DALLA BETTA, RALPH, NICKOLAS, SARENTO, G
• Format: Patent
• Language: English; French; German
• Published: 13.08.2003
• Edition: 7
• Subjects: AIR; AIR INTAKES FOR JET-PROPULSION PLANTS; AIR SUPPLY; BLASTING; BURNERS; COMBUSTION APPARATUS; COMBUSTION ENGINES; COMBUSTION PROCESSES; CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS; DRAUGHT-INDUCING; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; GAS-TURBINE PLANTS; GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGHVELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; METHODSOR APPARATUS FOR COMBUSTION USING FLUID FUELOR SOLID FUEL SUSPENDED IN; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PHYSICS; REGULATING; SUPPLYING NON-COMBUSTIBLE LIQUID OR GAS; WEAPONS

Methods and apparatus, both devices and systems, for control of Zeldovich (thermal) Nox production in catalytic combustion systems during combustion of liquid or gaseous fuels in the post catalytic sections of gas turbines by reducing combustion residence time in the HC zone through control of the HC Wave, principally by adjusting the catalyst inlet temperature. As the fuel/air mixture inlet temperature (to the catalyst) is reduced, the HC Wave moves downstream (longer ignition delay time), shortens the residence time at high temperature, thereby reducing thermal Nox production. The countervailing increase in CO production by longer ignition delay times can be limited by selectively locating the HC Wave so that thermal Nox is reduced while power output and low CO production is maintained. Nox is reduced to on the order of <3 ppm, and preferably <2 ppm, while CO is maintained <100 ppm, typically <50 ppm, and preferably <5-10 ppm.