Purification of particulate materials exhausted by diesel engine using high concentration and efficient ozonizer

研究了一种利用高效高浓度臭氧发生技术分解柴油机颗粒物的新方法。在使用过滤器等充分致密化/局部化柴油机废气中低浓度的NOx和氮氧化物之后，首先，对柴油机排气中的有害物质进行了定位试验，确定了其在过滤器表面（穿透直径为2μm）的位置。在过滤器中进行捕集，使过滤器后的浓度低于烟度计的最低检测限。废气中CO和CO_2含量的增加和NOx含量的降低表明废气中NOx和NOx同时处理的可能性。在柴油机系统中，由于过滤器的插入而引起的压力损失是一个问题，为此，开发了一种新的收集系统，该系统包括一个用于过滤器的静电除尘器和一个含有PZA（Pt-Zr_2-Al_2O_3）催化剂的蜂窝板，它们位于同一DBD空间中。由此，在DC 2kV的施加电压和81/min的气体流速下，65%的可捕集颗粒（平均0.3μm），结果表明，静电除尘对收集亚微米级粉尘是有效的。在相同的电极布置下，可以均匀地产生从工频到10 kHz的DBD，并且获得了300℃的温升。由于NOx在PZA蜂窝中的吸附/脱附可通过温度控制来实现，因此该系统的有效性变得明显。

A new decomposition method for diesel particulate materials (DPM) using efficient and high-concentration ozone generation technology has been investigated. After sufficient densification/localization of the DPM and nitric oxides ~with low concentration in diesel exhaust gas using a filter etc., these environmentally hazardous materials are exposed and decomposed by dielectric barrier discharge (DBD).First, localization to the filter surface (penetration diameter 2μm) of DPM in diesel engine exhaust gas was tried. The collection of the DPM was carried out to the filter, and the concentration after the filter was made to below the minimum detection limit of a smoke meter. Observations of the increase of CO and CO_2 and the decrease of NO_x in processed gas suggest that the possibility of the concurrent processing of DPM and NOx in exhaust gas. However, in application to the diesel engine system, it became clear that the pressure loss by filter insertion poses a problem.In order to solve this, the new collecting system of which involves an electrostatic precipitator for DPM and a honeycomb sheet containing PZA (Pt-Zr_2-Al_2O3) catalyst in the same DBD space was developed. Thereby, 65 % of DPM particle (average of 0.3μm) were caught at applied voltage of DC 2kV and gas flow rate of 81/min., and it was shown that electrostatic precipitation is effective to collect sub-micron DPM. Moreover, DBDs operated from commercial frequency to 10 kHz were generated uniformly by the same electrode arrangement, and the temperature rise of 300℃ has also been attained. Since adsorption/desorption of NOx in PZA honeycomb was realizable with temperature control, the validity of this system became clear.