Design Of Iron-based Oxides For Elemental Mercury Removal From Coal Combustion Flue Gases

Mercury pollution caused by coal combustion is the major source of global atmospheric mercury pollution. In order to use coal source cleanly and effectively, various countries and regions have launched a series of relative laws and regulations to restrict all kinds of coal combustion contaminants. But because of our countries' basic national conditions, removal of mercury technology and adsorbent for our country' s coal-fired power stations are not designed and developed. This dissertation embarks from two aspects of calculation and experiment and aims to design a high efficient and cheap Fe-Mn oxides for removal of elemental mercury from coal-fired flue gas.In this dissertation, firstly destiny functional theory (DFT) was used to calculate and analyze different forms of mercury adsorbed on a-Fe2O3(001) surface. The results show that adsorption of elemental mercury on a-Fe2O3 (001) surface is only physisorption and very weak. Adsorption energy of HgO vertically adsorbed on Otop performed best. While HgO adsorption on a-Fe2O3(001) surface is chemisorption. Two stable equilibrium structure could get through HgO vertically adsorbed on Fetop.Based on theoretical computational studies, serials of Fe-Mn oxides used for removal of elemental mercury from coal-fired flue gases were prepared. Adsorbent preparation optimization showed that sorbents whose preparation condition of Fe/Mn molar ratio of 1:1 and calcination temperature with 400 ? have high stable and efficient ability for HgO removal. Reaction temperature from 100 to 400 ? show little difference on HgO removal, which all had more than 98% HgO removal efficiency. Both CO2 and O2 could improve HgO removal efficiency. And O2 concentration change dose not contribute removing more HgO.Mixing with quartz could promote sorbents utilization efficiency. Exhausted sorbent regenerated by desorption also showed high HgO removal efficiency.