Abstract
Five coals (C: 76–88 wt%, daf) were treated with sulfuric acid, hydrochloric acid and nitric acid. The treated coal and the char were gasified with a H2O (24%)-N2 mixture and an O2 (2%)-N2 mixture at constant rates of 2°C/min and 20°C/min, and their reactivities were analyzed with our modified volume reaction (MVR) model. With nitric and hydrochloric acids, differences in coal properties and gasification rates among coals persisted after acid treatment. By contrast, after sulfuric acid treatment all of the coals showed similar levels of fixed carbon content and of moisture-holding capacity. These treated coals and chars show similar gasification reactivity. This confirms our previous proposal that the reactivity of coal char can be correlated with two characteristic properties of the parent coal: the fixed carbon content (FCf) and moisture-holding capacity (Ωf).
