Power Plant Flue Gas Desulfurization By Activated Coke

Coal accounts for about 70% of China’s total commercial primary energy consumption and has been of crucial importance to the rapid economic expansion. SO2 emission derived from coal combustion is the major source of atmospheric pollution. The desulphurization with activated coke has been paid more attention in recent years. It is not only an effective SO2 removal method but also recovery the sulfur resources at the same time.Inner Mongolia lignite was used to generate activated coke by coal crushing, acid pickling, carbonization and activation. The pore structure of raw active coke was characterized by N2 isothermal adsorption/temperature-programmed desorption. The results showed that the active coke exhibited abundant micro-pore. The effects of process conditions on desulphurization capacity, including particle size, flue gas temperature, residence time, SO2, O2, and H2O concentration, were carried out in a fixed bed reactor. The activated coke showed higher sulfur capacity and longer breakthrough time under the conditions of the fine active coke, longer residence time, lower inlet concentration of SO2. Reaction temperature of 100℃, O2 content of 6% and H2O content of 5% were suitable for the desulphurization in this study. H2O and O2 in the flue gas played a key role in the desulfurization process.The desulfurization performance of the modified coke was subsequently investigated. The surface basic group and the desulfurization performance were increased by HNO3 modification. The sulfur capacity increased with the increase in the surface basicity concentration. The breakthrough time of activated coke by KOH modification reached up to 400min, which was longer than that of the raw active coke (234min). The desulfurization performance of activated coke modified by nitrate were improved, and copper nitrate modified active coke desulfurization is the best.The regeneration performance of the activated coke was studied. It was found that desulfurization efficiency and adsorption quantity decreased with increasing the regeneration number.