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摘要
Experimental studies on diesel soot oxidation under a wide range of conditions relevant for modern diesel engine exhaust and continuously regenerating particle trap were performed. Hence, reactivity tests were carried out in a fixed bed reactor for various temperatures and different concentrations of oxygen, NO2 and water (300-600 degrees C, 0-10% O-2, 0-600 ppm NO2, 0-10% H2O). The soot oxidation rate was determined by measuring the concentration of CO and CO2 product gases. The parametric study shows that the overall oxidation process can be described by three parallel reactions: a direct C-NO2 reaction, a direct C-O-2 reaction and a cooperative C-NO2-O-2 reaction. C-NO2 and C-NO2-O-2 are the main reactions for soot oxidation between 300 and 450 C. Water vapour acts as a catalyst on the direct C-NO2 reaction. This catalytic effect decreases with the increase of temperature until 450 C. Above 450 degrees C, the direct C-O-2 reaction contributes to the global soot oxidation rate. Water vapour has also a catalytic effect on the direct C-O-2 reaction between 450 degrees C and 600 degrees C. Above 600 degrees C, the direct C-O-2 reaction is the only main reaction for soot oxidation. Taking into account the established reaction mechanism, a one-dimensional model of soot oxidation was proposed. The roles of NO2, O-2 and H2O were considered and the kinetic constants were obtained. The suggested kinetic model may be useful for simulating the behaviour of a diesel particulate filter system during the regeneration process.
- 出版日期2014-8
