Influence of low-rank coal char properties on their SO2 removal capacity from flue gases. 2. Activated chars Original Research Article

The goal of this paper is to show that after the development of porosity by steam activation of chars obtained by N2 pyrolysis, the performance of some of them in SO2 removal from flue gas is comparable with data found in the literature using commercial materials. The adsorption of SO2 was carried out at the following conditions: a temperature of 100 °C, 1 second residence time, 10% (v/v) H2O, 6% (v/v) O2, 1000 ppmv SO2 and N2 as balance. Different techniques were used to evaluate the physical and chemical characteristics of the samples. An optimization of the steam activation process was done using BET surface area as the variable to be maximized. However, it has been shown that the SO2 removal capacity of the activated chars studied depends not only on their surface area but also on a balance between the content and type of oxygen functional groups and the surface area.