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

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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.