INFLUENCE OF LOW-RANK COAL CHAR PROPERTIES ON THEIR SO2 REMOVAL CAPACITY FROM FLUE-GASES - 2 - ACTIVATED CHARS

The goal of this paper is to show that after the development of porosi ty by steam activation of chars obtained by N-2 pyrolysis, the perform ance of some of them in SO2 removal from flue gas is comparable with d ata found in the literature using commercial materials. The adsorption of SO2 was carried out at the following conditions: a temperature of 100 degrees C, 1 second residence time, 10% (v/v) H2O, 6% (v/v) O-2, 1 000 ppmv SO2 and N-2 as balance. Different techniques were used to eva luate the physical and chemical characteristics of the samples. An opt imization of the steam activation process was done using BET surface a rea as the variable to be maximized. However, it has been shown that t he SO2 removal capacity of the activated chars studied depends not onl y on their surface area but also on a balance between the content and type of oxygen functional groups and the surface area. (C) 1998 Elsevi er Science Ltd. All rights reserved.