Surface-Stabilized Fuel Injectors With Sub-Three PPM NOx Emissions for a 5.5 MW Gas Turbine Engine

Abstract

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultralow NOx emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively perforated porous metal surface. This allows stable operation at low reaction temperatures. A previous ASME paper (IJPGC2002-26088) described the development of this technology from the proof-of-concept stage to prototype testing. In 2002 development of these fuel injectors for the 5.5 MW turbine accelerated. Additional single-injector rig tests were performed which also demonstrated ultralow emissions of NOx and CO at pressures up to 1.68 MPa (16.6 atm) and inlet temperatures up to 670°K (750°F). A pressurized multi-injector “sector rig” test was conducted in which two injectors were operated simultaneously in the same geometric configuration as that expected in the engine combustor liner. The multi-injector package was operated with various combinations of fired and unfired injectors, which resulted in low emissions performance and no adverse affects due to injector proximity. To date sub-3 ppm NOx emissions with sub-10 ppm CO emissions have been obtained over an operating range of 0.18–1.68 MPa (1.8–16.6 atm), inlet temperatures from 340 to 670K (186–750°F), and adiabatic flame temperatures from 1740 to 1840K (2670–2850°F). A full scale multi-injector engine simulation is scheduled for the beginning of 2003, with engine tests beginning later that year.