Preparation of powdered activated coke for SO2 removal using different coals through a one-step method under high-temperature flue gas atmosphere

Abstract • Powdered activated coke (PAC) used for SO2 adsorption can be prepared using pulverized coal through a one-step method under a high-temperature flue gas atmosphere, and the PAC performance is significantly affected by the coal type. In this study, five coals with different ranks were used to prepare the PACs through this method in a drop-tube reactor. The pore structures, bulk densities, surface morphologies, and chemical functional groups of the PACs were characterized, and their yields and SO2 adsorption capacities were determined. Results show that the PACs prepared from low-rank coals (IN-coal and ZD-coal) had developed pore structures, abundant oxygen-containing functional groups and high SO2 adsorption capacities, but their yields were relatively low. As the degree of coalification increased, as in JJ-coal and RU-coal, the pore structure parameters, amount of oxygen-containing functional groups, and SO2 adsorption capacities of the PACs demonstrated a decreasing trend, whereas the yields increased. Besides, the XW-coal was found to be unsuitable for PAC preparation, because the resulting PAC had an undeveloped pore structure and a low SO2 adsorption capacity, and caking property of coal is an unfavorable factor in the PAC preparation. These conclusions can provide guidance for the selection of raw materials used to prepare PAC through the one-step method.