Fate of trace elements and ash formation during combustion and gasification of coal

点击翻译按钮获取中文摘要

Coal represents more than 65% of total fossil fuel reserves in Canada and almost sixty million tons of coal is used every year for electricity production. Clean coal technology development is, therefore, a priority area of research and needs continuous improvements in increased efficiency and decreased pollutant emission. Trace elements (TEs) such as mercury, arsenic and selenium present in coal, even when present in parts per million levels, are of public health concern. There are two factors that determine the emission of trace elements: coal characteristics and the combustion environment. Coal characteristics include heterogeneity in both organic and inorganic matter including the distribution of trace elements in coal. These elements mostly evaporate during combustion and condense primarily on fine fly ash particles that are difficult to be captured. Any retention of the TEs in fly ash particles is strongly influenced by their association with other minerals in individual coal and mineral grains. The coal-mineral associations play an important role in the formation of fine particles, release of TEs and their subsequent condensation.