Experimental study on combustion characteristics of coal/NH3 in a flat flame burner

To meet the “peak carbon and carbon neutrality” targets, the gradual reduction of coal-fired electricity generation through the co-firing of coal and NH3 has emerged as a new pathway to achieve carbon reduction. However, the co-firing characteristics of coal and NH3 are not yet clear. Therefore, the coal/NH3 co-firing experiments were conducted based on a flat-flame burner to investigate the influence of ammonia blending ratio (E(NH3), 0−100%) and coal/NH3 injection methods (pre-mixed, non-pre-mixed) on combustion characteristics. Camera, flue gas analyzer, and thermocouples were used to observe flame morphology, gas composition, temperature distribution along the centerline heights above the burner (HAB), and measure the unburned carbon content in fly ash. The results showed that during the initial stage of combustion, the competition for O2 between coal and NH3 was more pronounced. The NH3 combustion in the combustion zone created a rich water vapor atmosphere. Under low E(NH3) conditions in pre-mixed combu