Ammonia-coal co-firing is one of the important ways to achieve carbon reduction of coal-fired thermal power units

but the research on high proportion ammonia co-firing is rare. In order to further explore the feasibility of high-proportion ammonia co-firing

the mechanism model of ammonia-coal co-firing is established

and the ammonia-coal co-firing and pure ammonia combustion process of 4 MW boiler is simulated by using computational fluid dynamics(CFD) method. The error between CFD calculation results and experimental data is less than 3%. The experimental results show that

when ammonia is co-fired with coal

the flame temperature decreases by about 30 ℃ and the carbon dioxide volume fraction decreases by about 20% for every 20%increase in the co-firing ratio. When the ammonia co-firing ratio is increased from 0 to 40%

the NO volume fraction at the furnace outlet increases by about 77.33%

and the carbon content in fly ash increases from 4.65% to 6.16%; when it is increased from 0 to 60%

the NO volume fraction increases by about 136.44%. When excess air ratio of ammonia-coal co-firing is 1.15

the fuel burnout and nitrogen oxide generation are optimized. The two-stage input of ammonia fuel can reduce the NO volume fraction at the furnace outlet by 31.07% compared with the ungraded input. Compared with the combustion flame of coal combustion and ammonia-coal co-firing

the flame temperature of pure ammonia combustion is lower

the ignition distance is longer and the tangent circle diameter is larger. When pure ammonia is fired

the NO mass concentration at the furnace outlet is 475 mg/m~3

and the escaping ammonia concentration is close to 0.