丙烯在模型孔中CVI过程的热解炭沉积

发布时间：2018-05-22 13:39

本文选题：热解炭 + 丙烯　；参考：《新型炭材料》2017年05期

【摘要】：本文在温度为1 223 K,总压强40 kPa(N_2∶C_3H_6=9∶1)和停留时间0.56 s下,以丙烯为前驱体在内径为1.0 mm和长度31.0 mm的模型孔中裂解沉积生成热解炭。以15 h为沉积周期经75 h沉积实验得到最终试样,通过制样观察热解炭沿模型孔长度方向的沉积厚度,分析在基底水平和垂直方向上热解炭的沉积速率变化。结果表明,在该实验条件下热解炭沿模型孔长度方向由孔口到末端的沉积速率降低;而在垂直方向位置较低处的模型孔,热解炭沿长度方向的沉积速率梯度较小。通过耦合丙烯的均气相反应机理和总括反应机理,对该实验条件下丙烯在模型孔中的热解炭沉积过程进行模拟。在平推流反应器模型中,运用均气相反应机理对丙烯裂解的气相组分变化进行模拟,并将平推流反应器相应位置的气体组分浓度作为对应模型孔入口的初始浓度。运用总括反应机理的热解炭沉积模型,对丙烯在模型孔中的化学气相渗透过程进行模拟。对照热解炭在模型孔中沉积厚度的实验结果,证明该模型的合理性。模拟和实验结果表明通过减少气体停留时间可适当减缓热解炭表面封孔现象。
[Abstract]:At a temperature of 1 223 K, a total pressure of 40 KPA and a total pressure of 40 KPA, the pyrolytic carbon was formed by pyrolysis and deposition of propene as precursor in a model pore with an internal diameter of 1.0 mm and a length of 31.0 mm. The final sample was obtained by 75 h deposition experiment with 15 h deposition cycle. The deposition thickness of pyrolytic carbon along the length of model pore was observed by sample preparation, and the deposition rate of pyrolytic carbon in horizontal and vertical direction of substrate was analyzed. The results show that the deposition rate of pyrolytic carbon decreases in the direction of pore length from the orifice to the end of the model under this experimental condition, but the deposition rate gradient along the length of the pyrolytic carbon is smaller at the lower perpendicular position. The pyrolytic carbon deposition process of propylene in the model pore was simulated under the experimental conditions by coupling the homogeneous reaction mechanism and the overall reaction mechanism of propylene. In the model of flat push-flow reactor, the change of gaseous component of propylene cracking was simulated by the mechanism of homogeneous gas phase reaction, and the concentration of gas component in the corresponding position of the reactor was taken as the initial concentration of the corresponding pore entrance. The chemical vapor permeation process of propylene in the pore of the model was simulated by the pyrolytic carbon deposition model based on the overall reaction mechanism. Compared with the experimental results of deposition thickness of pyrolytic carbon in the pore of the model, the rationality of the model is proved. The simulation and experimental results show that the sealing phenomenon of pyrolytic carbon surface can be reduced by reducing the gas residence time.
【作者单位】：上海大学材料复合及先进分散技术教育部工程中心;上海航天设备制造总厂;
【基金】：教育部博士点基金(20113108120019) 上海人才发展资金(2011028) 航空基金(2013ZFS6001) 上海市科委基金(13521101202)~~
【分类号】：TQ127.11

【相似文献】