Evaluation of a Mg-Based Additive for Particulate Matter (PM)2.5Reduction during Pulverized Coal Combustion†

This paper aims to evaluate the addition of a Mg-based additive to coal on the emission/reduction of particulate matter (PM) during coal combustion. Four pulverized coals with different mineralogical properties were investigated. Each of them was mixed with Mg-based additive and combusted at 1723 K in a lab-scale drop tube furnace (DTF). The results indicate that the Mg-based additive tested here has a pronounced impact on particle size distribution of PM and the morphologies of individual ash particles. For all of the coals tested here, the addition of the Mg-based additive increased the coarse ash fraction and substantially reduced the amount of ash particles smaller than 2.5 μm (PM2.5). This is because the Mg-based additive is able to reduce the ash melting point via the formation of low-melting eutectic compounds, which promote the coalescence among sub-micrometer mineral particles. The effect of the Mg-based additive on PM2.5 reduction also depends upon the properties of the original minerals present...