Ammonia Cofiring with Coal for a Sustainable Green Power Generation: Progress and Outlook

Carbon dioxide (CO2) emissions present a significant ecological challenge due to their detrimental effects on the climate. Ammonia (NH3) is a prospective fuel to be cofired with coal to control CO2 emissions without incurring substantial infrastructure changes. The technical potential of NH3-coal cofiring in combustion behavior, emission control processes, and formation of nitrogen oxide (NOx) is discussed in this review article. The combustion of NH3 is promising for decarbonization, although it is associated with challenges in controlling NOx emissions. Injection of NH3, air staging, and optimization of the burner have been put forward to restrict NOx and N2O formation without compromising combustion efficiency. Recent studies suggest that cofiring NH3 in controlled ratios can restrict CO2 emissions without compromising NOx emissions beyond regulatory limits by utilizing efficient injection strategies and overfire air management. This study integrates a fundamental understanding of the burner design, combustion kinetics of coal-NH3, and emissions control strategies, while assessing its potential as a cleaner energy production fuel. The findings highlight that while incorporating NH3 offers a tempting decarbonization pathway, additional efforts are needed to improve combustion and fortify emission control strategies, emphasizing the urgency of this research.