As a carbon free fuel

ammonia coupled combustion on coal-fired units can achieve pollution reduction and carbon reduction

which is of great significance to helping achieve the “double carbon” target in China. The advantages and disadvantages of ammonia as an alternative fuel

coupled ammonia combustion characteristics of coal-fired units and the latest progress in related research were investigated. It is believed that when the ammonia mixing ratio is less than 20%

the appropriate flow rate and way should be adopted to inject ammonia into the furnace area with relatively low cocentration of O_2 and high concentration of NOx

which has little influence on combustion performance

such as combustion stability

NOx concentration and carbon content of fly ash. The carbon emission intensity and thermal performance of coupled ammonia combustion of a 330 MW coal-fired unit were calculated

and economic analysis on the two carbon emission reduction methods was carried out based on the production cost of “green ammonia”. The results show that

the boiler exhaust temperature decreases and the boiler thermal efficiency increases slightly after adding ammonia. When the ammonia mixing ratio is 20%

the annual carbon emission reduction of the unit is about 267 300 t

and the carbon emission intensity is 719.90 g/(kW·h).Under the range of 20% carbon emission reduction and considering the fluctuation of coal price

when the electricity price of “green ammonia” is lower than 0.10～0.18 yuan/(kW·h)

ammonia blending has economic advantages compared with carbon capture and storage. Relevant conclusions can provide reference for the research and practice of ammonia mixing in coal-fired units.