The Study On Adsorption Properties Of Denitrification By Cuo/γ-al₂o₃ Catalysts

NOX from coal combustion process results in serious harm to the environment. The CuO/γ-Al2O3 catalysts can remove nitrogen oxides from flue gas effectively. At present, the study on this catalysts is main about the removal effect of technology and chemical processes,but less on NH3 and NO adsorption properties on catalysts surface. So, it was necessary to study on the adsorption mechanism of catalysts and analyze the impact to denitrification efficiency, which was helpful to the improvement of catalyst performance.Preparing a highly efficient catalytic adsorbent is at the root of this study. Above all, the process of preparing CuO/γ-Al₂O₃ catalysts by the sol-gel method was introduced. And then, the denitrification efficiency of CuO/γ-Al2O3 catalysts was defined in a fixed-bed reactor. To obtain more information about the adsorption behaviors of NH3 and NO in this system, desorption experiments and transient behaviors had been carried out. Eventually, the chemical adsorption properties of NH3 and NO molecules on CuO/γ-Al 2 O3 catalysts surface had been investigated by using a quantum chemistry calculation, the results of which might be of help to understand the denitrification mechanism and explain the adsorption to catalysts performance.The main conclusions of this paper are as follows: the sol-gel-derived CuO/γ-Al2O3 granules had good structural characteristics and higher denitrification activity; the adsorption capacity of NH3 and NO on the catalyst surface was considerable and the adsorption played an important role in the reaction, O2 could effectively complement consumed lattice oxygen of the catalysts surface to maintain high denitrification activity during a long time; NO was relatively difficult to be adsorbed on the catalysts surface because of needing to overcome a larger energy barrier. while, NH3 adsorption was easy ,the suitable adsorption intensity enabled the sufficient adsorption capacity and made the products timely transferred and excluded to ensue rapid and efficient reaction in SCR. Changed molecular structure was an important reason for lower catalyst activity. the adsorption induced molecular structure changed and charge redistributed, which was in favor of reactant molecules internal covalent bond broken and a new product generated.