(87b) Effects on Ammonia Injection Directions for Coal-Ammonia Co-Firing in a Circulating Fluidized Bed Combustion Test Rig

Ammonia (NH₃) co-firing both pulverized coal boiler and circulating fluidized bed boiler is a promising technology for reducing greenhouse gas emissions, important to achieve 2030 NDC(Nationally determined contribution) and 2050 carbon neutrality. By this situation, researches on NH₃ co-firing are conducting since 2021 in South Korea. In order to be close to commercialization of NH₃ co-firing, optimization of ammonia injection method and the comprehensive combustion characteristics, including pollutant emission, combustion efficiency, and ash properties on coal-ammonia co-firing should be investigated. Therefore, in this work, NH₃ co-firing characteristics on ammonia injection directions in dense bed zone were observed to optimize NH₃ supply way during coal–NH₃ co-firing ratio (21.2% as thermal input basis) in a pilot-scale circulating fluidized bed (CFB) combustion test rig. As a result, compared with only coal-fired combustion, all NH₃ co-firing operations on variation of ammonia injection directions simultaneously reduced NO and CO₂ emission, achieving the highest combustion efficiency without ash-related problems.