Effect of Al2O3 additive on formation of PM2.5 in O2/CO2 atmosphere during coal combustion
The influence of Al<inf>2</inf>O<inf>3</inf> additive on the emission characteristics of inhalable particles has been studied with a tube furnace. The combustion tests were carried out at 1123K under O<inf>2</inf>/CO<inf>2</inf> conditions. The inhalable particulates after combustion were collected into an Electrical Low Pressure-Impactor (ELPI). Results indicate that Al<inf>2</inf>O<inf>3</inf> additive is an important factor for the formation of PM<inf>2.5</inf> (particulates with diameters less than 2.5µm) during coal combustion under O<inf>2</inf>/CO<inf>2</inf> atmosphere. The number and mass concentrations of PM<inf>1</inf> diminish, but the number and mass concentrations of PM<inf>1–2.5</inf> enhance slightly after Al<inf>2</inf>O<inf>3</inf> is added. The size distributions of PM<inf>2.5</inf> are similar, displaying two peaks around 0.2µm and 2.0µm, respectively. With increasing the additive weight ratio of Al<inf>2</inf>O<inf>3</inf>, the concentrations of Na, K, Cu and Pb decrease.