Detailed Mechanism And Numerical Simulation Of Catalytic Reduction Of Nitric Oxides

With the development of industry, atmospheric pollution is becoming the foucus of world. NO_X released by engines and coal combustion is one of the main sources of atmospheric pollution. Nitric oxides of automobile exhaust is main source of atmospheric pollution in the big city, it is origin of photochemical smog; In addition heat power is main way of power generation in our country, NO_X produced by coal combustion is also one of the main sources of atmospheric pollution.Techniques of nitric oxides reduction are introduced in this paper, selective catalytic reduction technique is more effect and widely used among these techniques. Some basic theory of heterogeneous catalysis is introduced, and detailed mechanisms of SCR have been researched in this paper. Surface mechanism is built on summary of article and experiment results. Preexponential factors are calculated by transition state theory, and activation energy is calculated by the Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) semiempirical method. Complete surface detailed mechanisms are built on the base of caculation results. The experiment reactors are simulated by coupling mathematic model and surface mechanism model. Simulation results are analyzed by comparing with experiment results, and analyze catalytic efficiency under different conditions, and do some reaction mechanism sensitive analysis. The analysis shows that Fe₂O₃. Pt and Ir all have good performance on NO_X reduction. Fe₂O₃ is an ideal catalyst because of its good catalytic peformance and cheapness. Now Pt is widely used as an active component of three-way catalysts. Catalytic performance of Ir catalyst for reduction of nitric oxides in the presence and excess oxygen is very good. It is one kind of excellent catalyst for NO_X reduction.