Experimental investigation of combustion characteristics of ammonia with sub-bituminous coal in a pilot circulating fluidized bed combustor

Recent research on power plant technology has focused on employing ammonia as a supplementary fuel with coal to reduce carbon dioxide emissions from coal-fired power plants. However, most of this research has concentrated on pulverized coal systems, with fewer studies on circulating fluidized bed (CFB) combustion systems. Additionally, no research has analyzed combustion and environmental impacts under varying operational conditions with a fixed ammonia co-firing ratio. This study advances the development of coal–ammonia co-firing technology for use in CFB power plants by conducting experiments on a 50 kWth CFB combustion test rig. The co-firing characteristics were evaluated by progressively increasing the ammonia co-combustion rate to 20%, calculated on a high calorific value basis relative to sole coal combustion. Furthermore, this research explored the variations in operational conditions during 20% ammonia co-firing to assess their effects on the temperature distribution within the combustor and the composition of the exhaust gases. The findings elucidate the combustion efficiency, thermal behavior, and emission profiles associated with coal–ammonia co-firing, thereby guiding the optimization of operational strategies to minimize the carbon footprint of CFB power plants.