Development of surface area and pore structure for activation of anthracite coal

The use of anthracite coal as a feedstock for activated carbon is investigated. A rotating reactor was constructed to activate the coal in a carbon dioxide environment at three temperatures. The reaction was started and stopped by switching the gas atmosphere from carbon dioxide to nitrogen. The change in anthracite weight was followed over time, allowing a study of the overall kinetics of the reaction. Samples from the reactor were taken at specific time intervals and surface area was assessed. It was determined that BET and micropore surface areas were functions of conversion and activation temperature. Likewise, for each of the activation temperatures, good control of BET to micropore surface area ratios was demonstrated. Typical BET surface areas of nearly 1000 m2/g were obtained along with the ability to alter the micro- and meso-porous structure. Testing of these activated carbons for use in electric double layer capacitors displayed a capacitance of 140 F/g. These results are comparable to other research carbons for this application. Results on the activation of the two anthracite coal samples are reported along with details of the pore development and global kinetics of activation.