Yuran Li
Chinese Academy Sciences, China
Title: One way to improve the de-NO activity in SCR of NO with NH3 over a low-rank activated coke
Biography
Biography: Yuran Li
Abstract
For the flue gas from coal-fired power plants, the usual purification process is the limestone-gypsum wet flue gas desulfurization combined with the selective catalytic reduction (SCR) denitrification by NH3. Compared with the method of series connection of individual pollutant control, simultaneous removal of multi-pollutant is prospective due to its cost-effectiveness. Activated coke can be utilized in 130-150 oC as a catalyst in catalytic reduction of NOx by NH3, simultaneously adsorbing SO2 and removing multi-pollutants, such as SO3, dioxin and heavy metals. The desulfurization efficiency is usually higher than 90%, the denitrification efficiency ranges 30-50% in SCR reaction with NH3.The purpose of this study is to improve the desulfurization and denitrification performance on the activated coke through the modification and regeneration in various atmospheres and then to reveal which functional groups play a key role on SCR. We used a low rank commercial activated coke produced by Xinhua chemical plant in this work. The AC modified by H2O2 and NH3·H2O can increase the content of oxygen and nitrogen functional groups on the surface of it, then increase the absorption of SO2. The denitrification activity increased 1.5-2.6 times for the activated coke modified by H2SO4 than the fresh activated coke. The activated coke regenerated under NH3 atmosphere significantly improves the denitrification and desulfurization activities. The denitrification efficiency increased about 10-20% for AC modified by NH3·H2O or HNO3. After modification or regeneration of activated coke, the specific surface area, the pore size distribution, the total pore volume and the types of nitrogen and oxygen functional groups were changed compared with the fresh activated coke. There is a positive relationship between nitrogen or sulfur capacity of carbonyl oxygen of quinone groups, oxygen atoms in carboxyl groups, N-6 (pyridinic) and N-5 (pyrrolic and pyridonic) in the experiment of desulfurization and denitrification of activated coke.