Research progress on ammonia-coal co-combustion technology

CHEN Yongxu; HOU Yujie; WANG Chang'an; DAI Liangxu; JIA Zixiu; LI Yuhang; CHE Defu

Abstract：The ammonia-coal co-combustion technology aligns with China's national energy conditions,where the main status of coal will not fundamentally change in the short term.This technology is crucial for China to achieve carbon emis-sion reduction in the power system and meet the"carbon peaking and carbon neutrality objectives".However,due to the distinct combustion characteristics of ammonia compared to traditional fossil fuels,blending ammonia fuel into coal-fired boilers may result in issues such as reduced combustion stability and elevated NOx emissions.Based on relevant domestic and international research on ammonia-coal co-combustion,the existing problems of ammonia fuel are presented.The im-pacts of variables such as the ratio and injection location of ammonia,air distribution mode,and combustion temperature on the combustion and emission characteristics of ammonia-coal co-combustion are analyzed.Furthermore,changes in the reaction mechanism during ammonia-coal co-combustion are elucidated.The economic analysis of ammonia-coal co-com-bustion technology is also presented,along with future research and application prospects.The results indicate that under a 20%-40%ammonia blending ratio,the combustion and emission characteristics can meet energy conservation and emis-sion reduction engineering requirements through proper fuel staging,air staging,and oxy-fuel combustion.Ammonia-coal co-firing results in a decrease in overall furnace temperature,negatively impacting on fuel burnout and the reduction of NOx by ammonia and coal coke.Additionally,the H2O-rich atmosphere created by ammonia doping could enhance the generation of NOx.At a 20%ammonia co-firing ratio,boiler thermal efficiency remains essentially unchanged,while car-bon emissions can be reduced by approximately 20%.Furthermore,advancements in green ammonia production techno-logy could make the cost of co-combustion competitive with,or even more advantageous than pure coal combustion,fur-ther promoting the construction of China's new energy-based new power system.