Engineering development of advanced coal-fired low-emissions boiler systems. Fourth quarterly report, 1996

The goal of the NO{sub x} Subsystem is to achieve continuous operation of the Low Emissions Boiler System (LEBS) at NO{sub x} emissions at or below 0. 20 lb/MBtu through combustion techniques only, with a further target of 0.1 lb NO{sub x}/MBtu using supplementary advanced flue gas cleanup technologies if necessary. These goals places practical constraints that must be considered on the NO{sub x} Subsystem design. Not only must the boiler be designed to achieve time temperature mixing histories that minimize NO{sub x}, but it must also be designed to operate that way throughout its working lifetime. Therefore, NO{sub x} minimization strategies must be integrated into the control systems for every boiler component from the pulverizers to the stack. Furthermore, these goals must be met without increases in carbon loss and CO emissions from the levels achieved with current low-NO{sub x} combustion systems. Therefore, the NO{sub x} Subsystem requires not only sound mechanical designs of burners, furnace surface, and staging air/fuel injectors, but also sensors and software to allow control of their operation. Through engineering analysis, experimental testing, and numerical modeling in Phase 2, an advanced low NO{sub x} control system is being developed. The progress of these activities is presented in this report