| Firstly,the differential method（Achar-Brindley-Sharp-Wendworth,ABSW）,Arrhenius method and comprehensive combustion characteristics index S were used,studied the effects of NO2 on the oxidation characteristics of carbon black particles in the pre-oxidation（45～350℃）,post-oxidation（350～800℃）and the whole-oxidation processes（45～800℃）.The results showed that NO2 had positive effect on the oxidation regeneration of carbon black particles in the pre-oxidation period.under the NO2 atmosphere,the activation energy of carbon black particles gradually decreased,and S gradually increased with the increase of NO2concentration.,From 0.89×10-7%2min-2℃-3 to 1.96×10-7%2min-2℃-3;when NO2 and oxygen coexist,the concentration of NO2 was low,the oxidation of carbon black particles had synergistic oxidation effect,as the concentration of NO2 increases,the synergy increased first and then decreased.The synergy was most obvious when the concentration of NO2 was2000×10-6.At that time,the activation energy of carbon black particles was 107kJ·mol-1.S was1.89×10-7%2min-2℃-3.In the stage of post-oxidation,NO2 also had synergistic effect on the oxidation and regeneration of carbon black particles.Compared with carbon black particles oxidized under O2 atmosphere(oxidation activation energy value was 169kJ·mol-1,S was 1.11×10-7%2min-2℃-3),when NO2 gas participates under the oxidation reaction,the activation energy of the particles was significantly reduced,S shows a gradual upward trend,and the activation energy decreases from 169kJ·mol-1 to 110kJ·mol-1 with the NO2 concentration at2000×10-6,S increased from 1.11×10-7%2min-2℃-3 to 1.86×10-7%2min-2℃-3,increased by0.75×10-7%2min-2℃-3.During the whole oxidation progress,the activation energy of carbon black particles increased with the increase of NO2 concentration,the activation energy decreased first then increased,and S increased first and then decreased.The synergistic effect was most obvious when the concentration of NO2 was 1000×10-7.At this time,the activation energy was 156kJ·mol-1,and the S value was 1.4×10-7%2min-2℃-3.Through researched,found that NO2 and O2 had synergistic oxidation,and different oxidation stages,different NO2concentrations,the synergy was differented,which provided an important theoretical basis for the in-depth study of the oxidation and regeneration characteristics of carbon black and diesel exhaust particles.Secondly,Used the above three oxidation kinetics methods,experimented on the effects of different catalysts（catalyzed diesel particulate filter,CDPF carrier milled into powder for catalyst and Pt）on the oxidation characteristics of carbon black particles under different gas atmospheres（NO2,O2）.In the research of CDPF carrier catalyst,The results showed,NO2 and O2 have a certain synergistic effect on the combustion of particles.In the early stage of oxidation,the activation energy of particles gradually decreases with the increase of NO2concentration,from 183 kJ·mol-1 to 111 kJ·mol-1.It can be reduced from 162 kJ·mol-1 to 109kJ·mol-1;in the later stage of oxidation,the activation energy of particles gradually decreases with the increase of NO2 concentration,and it decreases the most in the catalytic state,with a decrease of about 28～52 kJ·mol-1;During the whole oxidation process,the activation energy of particles showed a trend of decreasing first and then increasing with the increase of NO2concentration.Under the action of the catalyst,the decrease was most obvious when the NO2concentration was 1000×10-6,about 93 kJ·mol-1.The effect of Pt catalyst on the catalytic characteristics of carbon black particles under different gas atmospheres（NO2,NO,O2）was studied.With the increase of oxygen concentration,S increased from 2.01×10-7%2min-2℃-3 to 6.36×10-7%2min-2℃-3 under the catalytic state,and S from 1.1×10-7%2min-2℃-3 increased to 3.53×10-7%2min-2℃-3,when the oxygen concentration at 20%,S was the largest,and S increased 2.83×10-7%2min-2℃-3;With different concentration of NO2,with the increase of NO2 concentration,the activation energy of the particles decreases and it was the smallest when the NO2 concentration was 1000×10-6,about 120 kJ·mol-1.The activation energy decreased by 59 kJ·mol-1,and S increased continuously with the increase of NO2 concentration,when the NO2 concentration was1000×10-6,S was the largest which was 5.66×10-7%2min-2℃-3;Under different NO atmosphere,the apparent activation energy of the particles decreases with the increase of NO concentration,and it was the smallest when the NO concentration was 1000×10-6,about 112 kJ·mol-1,and the activation energy was reduced by 67kJ·mol-1;S increased with the NO concentration increasing,when the NO2 concentration was 1000×10-6,S was the largest which was 6.26×10-7%2min-2℃-3.The study found that the addition of a catalyst can reduced the activation energy and ignition point of the particles,and explored the oxidation catalytic characteristics and oxidation mechanism of carbon black particles under different gas atmospheres under catalytic action,in order to deeply studied the oxidation of carbon black and diesel exhaust particles Provide theoretical basis for regeneration characteristics.In this paper,the thermodynamic method was used to analyze and study the oxidation characteristics of diesel particles.The oxidation characteristics of diesel particles under NO2/O2atmosphere can be obtained.These differences wound further affect the oxidation and regeneration of diesel particles in DPF and CDPF.The study of the oxidation characteristics of carbon black particles is of great significance,and it also provides a theoretical basis for the research and development of the post-processing system DPF and CDPF. |
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