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Title: DEVELOPMENT AND DEMONSTRATION OF AN ULTRA LOW NOx COMBUSTOR FOR GAS TURBINES

Technical Report ·
DOI:https://doi.org/10.2172/840382· OSTI ID:840382

Alzeta Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low 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. This technology is being commercialized under the product name nanoSTAR. Initial tests demonstrated low NOX emissions but, were limited by flashback failure of the injectors. The weld seams required to form cylindrical injectors from flat sheet material were identified as the cause of the failures. The approach for this project was to first develop new fabrication methods to produce injectors without weld seams, verify similar emissions performance to the original flat sheet material and then develop products for microturbines and small gas turbines along parallel development paths. A 37 month project was completed to develop and test a surface stabilized combustion system for gas turbine applications. New fabrication techniques developed removed a technological barrier to the success of the product by elimination of conductive weld seams from the injector surface. The injectors demonstrated ultra low emissions in rig tests conducted under gas turbine operating conditions. The ability for injectors to share a common combustion chamber allowing for deployment in annular combustion liner was also demonstrated. Some further development is required to resolve integration issues related to specific engine constraints, but the nanoSTAR technology has clearly demonstrated its low emissions potential. The overall project conclusions can be summarized: (1) A wet-laid casting method successfully eliminated weld seams from the injector surface without degrading performance. (2) Gas turbine cycle analysis identified several injector designs and control schemes to start and load engines using nanoSTAR technology. A mechanically simple single zone injector can be used in Solar Turbine's Taurus 60 engine. (3) Rig testing of single monolithic injectors demonstrated sub 3 ppmv NOX and sub 10 ppmv CO and UHC emissions (all corrected to 15% O2) at Taurus 60 full-load pressure and combustion air inlet temperature. (4) Testing of two nanoSTAR injectors in Solar Turbine's sector rig demonstrated the ability for injectors to survive when fired in close proximity at Taurus 60 full load pressure and combustion air inlet temperature. (5) Sector rig tests demonstrated emissions performance and range of operability consistent with single injector rig tests. Alzeta has committed to the commercialization of nanoSTAR injectors and has sufficient production capability to conclude development and meet initial demand.

Research Organization:
ALZETA CORPRATION
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EE); DISTRIBUTED ENERGY RESOURCES
DOE Contract Number:
FC36-00CH11051
OSTI ID:
840382
Country of Publication:
United States
Language:
English