Advancements and future outlook in fundamental research and technological applications for ammonia co-firing with coal

Abstract

Energy security and the “dual carbon” goals are impacting the global energy industry and supply chains, presenting some urgent needs for the secure, efficient, and green low-carbon transformation of energy and power systems in China. To ensure energy security, the coal-fired power plant will remain an important support for electricity supply security and the integration of renewable energy for a considerable period into the future in China. To achieve carbon neutrality, the energy system is gradually shifting from primarily relying on fossil fuels to primarily relying on renewable energy. However, the intermittency, randomness, and volatility of renewable energy make power system regulation more challenging, highlighting the issues of system balance and security. In this context, the zero-carbon fuels such as ammonia play an indispensable role in dealing with the intermittency of renewable energy. They can serve as carriers for long-term and large-scale energy storage to facilitate the large-scale integration of renewable energy and can also be flexibly used directly in power equipment such as boilers to replace fossil fuels. However, due to the differences in physical and chemical properties between zero-carbon fuels and fossil fuels, some challenges arise in the widespread utilization of ammonia fuel, such as poor flame stability and the generation of nitrogen oxides during combustion. Therefore, based on the feasibility, economy and necessity of ammoniac-coal co-combustion, this paper comprehensively reviews the chemical reaction kinetics, combustion characteristics (ignition, steady combustion) and pollutants characteristics (NOx, fly ash particles and soot) of ammoniac-coal co-combustion, and discusses the scaling laws of burner based on the dimensionless number. The efficient and stable combustion control strategy of existing industrial grade ammonia-coal burners is discussed in detail. The C—N fuel separation, air staged and their joint control technology can effectively reduce NOx emissions. In the future, artificial intelligence, big data and digital twin and other information technologies are integrated. It is expected to provide a scientific support and path reference for the research and development of the next generation of new green power generation system oriented to the dual carbon strategy from the source.

Keywords

• ammonia-coal co-combustion
• low-carbon
• nox
• staged combustion
• module magnification
• artificial intelligence