论文部分内容阅读
为了提高催化器CDPF(catalyzed diesel particulate filter)去除NOx和PM的性能,该文运用催化试验、发动机台架试验及模拟计算,研究了排气温度和催化器的基底材料特性对NOx还原和PM氧化的影响特性。通过活性评价和表征试验发现,由于La2Cu0.7Fe0.3O4表面具有较高的氧空位浓度和较强的晶格氧移动特性,所以300°C～500°C时具有较好的催化活性,且350°C～500°C时碳化硅较堇青石能更好地催化还原NO。发动机台架试验表明,由于碳化硅具有更高的孔隙率和更好的热交换特性,在1 600 r/min的75%和90%负荷工况时,碳化硅CDPF具有更好地催化去除NOx和PM的特性规律。模拟计算结果显示,具有较高过滤孔密度和比表面积的CDPF,由于较低的内部传质阻力和较高的传质特性,所以能较好地还原NOx和氧化PM。研究结果可为优化柴油机后处理器CDPF的催化性能提供科学依据。
In order to improve the performance of catalyzed diesel particulate filter (CDPF) to remove NOx and PM, a catalytic test, an engine bench test and a simulation calculation were performed to study the effect of exhaust temperature and the substrate material characteristics of the catalyst on NOx reduction and PM oxidation Impact characteristics. Through activity evaluation and characterization test, it is found that La2Cu0.7Fe0.3O4 has good catalytic activity at 300 ° C ~ 500 ° C because of its high oxygen vacancy concentration and strong lattice oxygen mobility. And 350 Silicon carbide exhibits better catalytic reduction of NO than cordierite at ° C ~ 500 ° C. Engine bench tests show that silicon carbide CDPF has better catalytic removal of NOx at 1 600 r / min at 75% and 90% duty cycle due to the higher porosity and better heat exchange characteristics of silicon carbide And PM characteristics of the law. The simulation results show that CDPF with higher density and specific surface area of filter can better reduce NOx and oxidize PM due to lower internal mass transfer resistance and higher mass transfer characteristics. The results can provide a scientific basis for optimizing the catalytic performance of CDPF engine.