王忠, 赵怀北, 瞿磊, 张登攀, 冯渊. 柴油机燃烧甲醇/生物柴油尾气颗粒物热解特性分析[J]. 农业工程学报, 2017, 33(4): 96-101. DOI: 10.11975/j.issn.1002-6819.2017.04.014
    引用本文: 王忠, 赵怀北, 瞿磊, 张登攀, 冯渊. 柴油机燃烧甲醇/生物柴油尾气颗粒物热解特性分析[J]. 农业工程学报, 2017, 33(4): 96-101. DOI: 10.11975/j.issn.1002-6819.2017.04.014
    Wang Zhong, Zhao Huaibei, Qu Lei, Zhang Dengpan, Feng Yuan. Pyrolysis characteristics of particulate matter from diesel engine fueled with methanol/bio-diesel[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(4): 96-101. DOI: 10.11975/j.issn.1002-6819.2017.04.014
    Citation: Wang Zhong, Zhao Huaibei, Qu Lei, Zhang Dengpan, Feng Yuan. Pyrolysis characteristics of particulate matter from diesel engine fueled with methanol/bio-diesel[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(4): 96-101. DOI: 10.11975/j.issn.1002-6819.2017.04.014

    柴油机燃烧甲醇/生物柴油尾气颗粒物热解特性分析

    Pyrolysis characteristics of particulate matter from diesel engine fueled with methanol/bio-diesel

    • 摘要: 采集了甲醇/生物柴油(5%、10%、15%)混合燃料在柴油机燃烧的尾气颗粒。采用热重分析仪和切线法、Flynn-Wall-Ozawa(FWO)热解动力学方法,研究颗粒挥发及氧化规律,分析了颗粒热解特征温度和活化能。结果表明:随着甲醇掺混量的增加,颗粒中H2O的质量分数由2.6%增加到3.5%,可溶有机物(soluble organic fraction,SOF)质量分数由26.1%增加到32.5%,SOF的质量变化速率增大,对应的峰值温度后移;在O2氛围中,SOF挥发阶段与在N2氛围中的表现基本一致,但质量变化速率明显增大;碳烟(soot)质量减小,由70.3%减少到63.8%,soot质量变化率峰值增大;SOF析出温度变化较小,soot起始燃烧温度明显降低,由488 ℃降低到458 ℃,SOF起始燃烧温度与燃尽温度均有所降低,颗粒的热解总反应时间缩短;颗粒的热解反应活化能由140.3 kJ/mol降低117.3 kJ/mol,颗粒的热解性能增强,颗粒更易被氧化。研究结果可为甲醇/生物柴油燃烧颗粒的处理及柴油机颗粒捕集器(diesel particulate filter,DPF)再生提供依据。

       

      Abstract: Abstract: Diesel exhaust particle matter is the main source of air pollutants PM2.5. It is limited not only on the quality but also on the number. Therefore, the widespread use of clean alternative fuel in diesel engine is one of the effective ways to reduce particulate emission. Previous study reported the effects of methanol/biodiesel blending fuel on the volatilization, oxidation process parameters and kinetic parameters of particle matter emitted from diesel engine. The volatilization, oxidation process parameters of particle matter varied with the methanol/biodiesel blending ratio (100%, 5%, 10%, 15%) were measured by the TGA/DSCI thermal analyzer, manufactured by Mettler, Switzrland. The mass change curves of the particles in the surroundings of N2 and O2 were obtained by thermo-gravimetric analyzer. Further, the volatilization and oxidation features of the particles were studied according to the pyrolysis curves (TG/DTG), the characteristic temperature and activation energy of pyrolysis of particles were calculated by tangent method and Flynn-Wall-Ozawa (FWO) pyrolysis kinetics. The results showed that when the content of H2O in particle matter was increased from 2.6% to 3.5%, the quality of soluble organic fraction (SOF) in particle matter could be increased from 26.1% to 32.5%, the peak of mass change rate and the temperature of the peak of SOF would be increased with the increasing of the methanol ratio. In O2 surroundings, the derivative thermal gravimetry curves of particle matter under 4 kind of blending fuels showed that the change way of SOF was consistent with that in N2 surroundings, but the peak value in O2 atmosphere was obviously greater. The soot mass showed a decreasing trend with the increase of ratio of methanol, which was decreased from 70.3% to 63.8%. In addition, the peak of mass change rate of soot was increased and the temperature of the peak was decreased, which indicated that the particles were more easily oxidized. The initial combustion temperature of soot was decreased from 488 ℃ to 458 ℃. Meanwhile, the SOF initial combustion temperature and the burnout temperature were slightly lower, and the total time of pyrolysis reaction of particles was shortened. The activation energy of particle matter was reduced from 140.3 kJ/mol to 117.3 kJ/mol. In summary, the pyrolysis properties of the particles were enhanced and the thermo chemical reaction of particles was easily carried out. These results could provide a theoretical basis for the treatment of methanol/biodiesel combustion particulates, and it is helpful to the design and application of diesel particulate filter (DPF).

       

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