Effects of Temperature and Chemical Speciation of Mineral Elements on PM10 Formation during Zhundong Coal Combustion

Particulate matter (PM) pollution from coal combustion is a leading contributor to the influence of atmospheric visibility, photochemical smog, and even global climate. A drop tube furnace was employed to explore the effects of temperature and chemical speciation of mineral elements on PM formation during the combustion of Zhundong coal. Chemical fractionation analysis (CFA), X-ray fluorescence (XRF), and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were used to investigate the chemical and physical characteristics of the solid samples. It can be indicated that the combustion of similarly sized coal particles yielded more PM10 when the combustion temperature was increased from 1000 to 1400 °C. Zhundong coal is fractionated with deionized water, ammonium acetate, and hydrochloric acid, and pulverized coal, after fractionation, is burned to study the influence of mineral elements with different occurrence forms, such as water-soluble mineral elements, exchangeable ion elements, hydrochloric acid soluble elements and acid-insoluble elements, on the formation of particles. The results show that water-soluble salts play an important role in forming ultrafine particles (PM0.2); Fe, Ca, and other elements in organic form are distributed in flue gas through evaporation during pulverized coal combustion. When the flue gas temperature decreases, PM1 is formed through homogeneous nucleation and heterogeneous condensation, resulting in the distribution of these two elements on PM1. Different fractionation methods do not significantly affect the distribution of Si and Al in the PM1–10 combustion process.