Effect of ammonia and coal co-firing on the formation mechanism and composition characteristics of particulate matter

Ammonia-coal co-firing is considered to be an effective method to reduce carbon dioxide emissions and the existing researches mainly focus on the combustion characteristics and NOx emission characteristics. In this study, co-firing of coal and ammonia was carried out in the high temperature drop tube furnace system with a large co-firing ratio of 0-50%. Firstly, the unburned fuels and the main composition of flue gas were measured as a baseline result. The results showed that ammonia co-firing will lead to the increase of NO and NOx concentration. Further, the particulate matters generated under different conditions were collected and tested. It was found that ammonia co-firing will affect the formation characteristics of particulate matter, especially submicron particulate matter. With the increase of co-firing ratio, the concentration of PM1 showed an overall increasing trend, but decreased at 20%. And ammonia co-firing will have an effect on the content of Si, Al, S and trace elements (As, Pb) in submicron particles. The content of water vapor, NOx in flue gas and combustion temperature have changed and affected the formation of SO3 and the gasification of silica and trace elements.