The Study Of Removal Of Carbon Soot In Combination Of Non-thermal Plasma And Catalysts

Diesel vehicles have been attracted widespread attention because of its good cycle thermal efficiency, high fuel economy, strong durability and low emissions of CO2, HC and CO. However, compared to gasoline vehicles, diesel exhaust particulate matter emission is much higher, about30～100times that of gasoline vehicle emission, which posed a serious threat on air environment and human health. Emission control of the diesel engines has become one of the highlights of the environmental catalysis research.Based on the emission control of carbon soot in diesel engines, a combined method of plasma-catalytic reaction was studied for removal of carbon soot over MnOx/CeO2catalysts at low temperature. We systematically studied the synergistic effect of plasma-catalytic removal of simulated diesel exhaust at different temperatures, different power and different flow rate. At the same time, in order to study the preparation and properties of the membranes, the catalysts were characterized by XRD, H2-TPR and Raman. Some specific conclusions from this work are drawn as follows:1.Typical waveforms of discharge voltage for dielectric barrier discharge plasma was a sine wave, and the typical waveform of discharge current was a form of superimposed pulse on a sine wave.2. The results of Al2O3, ZrO2, SiO2and CeO2catalysts combined with plasma on the removal of carbon soot showed that the performance of Al2O3with plasma for removal carbon soot was worst, while CeO2showed the best performance; and the conversion of removal of carbon soot improved with the increase of reaction temperature. The carbon soot removal efficiency over CeO2catalyst was71.0%just at the temperature of200℃.3. A good synergistic effect between the plasma and MnOx/CeO2catalyst was observed, the removal efficiency increased to94.3%just at the temperature of200℃. Different Mn loading experiments showed that5.0%MnOx/CeO2catalyst displayed the best performance. The increase of discharge power and the oxygen concentration were conductive to promote the removal efficiency of carbon soot for plasma-catalytic method, and the optimum flow rate for plasma-catalytic reaction was30ml·min-1. The reaction of carbon soot at different concentration in plasma over MnOx/CeO2catalyst showed that the conversion of carbon soot was reduced due to the decrease of its active particles in unit space with increase of carbon soot. The conversion curves of carbon soot in plasma at different reaction time over the catalysts showed that the increase of temperature was benefit for the conversion to target reaction in plasma-catalytic method.