Influence of low-rank coal char properties on their SO2 removal capacity from flue gases: I. Non-activated chars Original Research Article

The SO2 adsorption capacity of a series of chars obtained by N2 pyrolysis at different temperatures from a low-rank coal with high ash content was assessed. The adsorption process was carried out at representative flue gas conditions (100 °C adsorption temperature, 1 second residence time, 10% H2O v/v, 6% O2 vv, 1000 ppmv SO2). Chars obtained by nitrogen pyrolysis at 500, 600, 700, 800 and 900 °C were characterized by the following techniques: XRD, AA, FTIR, Hg porosimetry, N2 and CO2 surface areas, and acid-base titration. Correlations between the performance of these chars and their physicochemical features were investigated. The SO2 adsorption capacity of pyrolized chars depends mainly on their surface area, but the content and type of functional groups and their accessibility are also important parameters to be considered.