| This paper studied the diesel particulate filter (DPF) offline regeneration and continuous regeneration by ozone oxidation. (a) DPF offline regeneration tests were studied by ozone oxidation in a diesel particulate filter (DPF) offline regeneration system which consisted of diesel engine (R175) , particle trap (Φ90×150 mm), and ozone generator (CF-G10 ). (b) A NO and O3 fast mixing oxidation experiment device was set up based on the venturi tube principle, and NO and O3 fast mixing oxidation at the high temperatures was studied. The feasibility of continuous regeneration by ozone oxidation was also discussed. The main research contents and the results are as follows:1. The DPF could be regenerated effectively by ozone oxidation offline, and the regeneration efficiency reached more than 90%. But the ozone began to escape from DPF at certain time during offline regeneration process, and the larger the filtering gas flow, the more particulate captured, the earlier the ozone penetration occurred. The ozone penetration occurred at the time of 210 min, 180 min, 150 min after regeneration began, and the regeneration efficiency reached 73%, 70%, 65% when the DPF's filtering gas flow rate were 20Nm3/h, 25Nm3/h, 33Nm3/h respectively. The ozone penetration occurred at the time of 150 min, 200 min, 240 min after regeneration began when the DPF's filtering time were 1 hour, 1.5 hour and 2.2. Injecting the regeneration gas upstream DPF was conducive to regenerate the DPF completely, and the larger the regeneration gas flow, the less influence on ozone penetration was. Injecting the regeneration gas reversely or closing the DPF's central region was conducive to improve the regeneration uniformity and ozone utilization rate, and the ozone penetration occurred later. After 360min regeneration, the regeneration efficiency reached 85%, 89% when the regeneration gas flow rates were 0.6 Nm3/ h, 1.2 Nm3/ h respectively. For DPF filtering exhaust gas for 1 hour and the regeneration gas flow rate was 0.6 Nm3/ h, the ozone penetration occurred at the time of 150 min, 170 min, and the regeneration efficiency reached 65%, 81% respectively when the regeneration gases were injected upstream in forward and reverse direction, after 480min regeneration, the regeneration efficiency reached 88%, 95.5%. And the ozone penetration occurred at the time of 200 min, 240 min, and the regeneration efficiency were reached 60%, 73% when the regeneration gases were injected downstream in forward and reverse direction, after 480min regeneration,, the regeneration efficiency were reached 67%, 80.6%. Closed the DPF's central region, the ozone penetration occurred later, and the regeneration efficiency increased about 2% when ozone penetration occurred.3. It is conducive to oxidize the PM that the temperature or the (NO+O3) concentration increased. The PM was oxidized by (NO+O3) (1000ppm) for 40min, the pressure drop fell to 700Pa at 250℃, 1800Pa at 300℃and 2000Pa above 350℃, the regeneration efficiency reached 28%, 80%, 94% respectively. O3 and NO fast mixed in a venturi tube reactor, and the ozone utilization rates reached 100% , 50%, 75.8%, 23.1% as the mole ratio [O3] : [NO] was 1:1, at the temperatures of 250℃, 300℃, 350℃and 400℃. The ozone utilization rate reached 29.6%, 33.8%, 43.7% when the mole ratio [O3]: [NO] were 0.5, 1, 1.5 at 375℃. The ozone utilization rate reached 22.7%., 33.8%, 41.0% at the mole ratio [O3] : [NO] of 1:1 and gas flow rates 10m/s, 30m/s, 50m/s at 375℃respectively.4. This paper discussed the DPF regeneration system of offline regeneration and continuous regeneration by ozone oxidation. For type 6100 diesel engine, the total power of offline regeneration system was 1.063.19kW,which was 0.92.7% of diesel engine power, and the total power of continuous regeneration system was 0.852.55kW, which was 0.722.16% of diesel engine power. |
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