丙烷CVI工艺热解炭沉积非均相反应动力学模拟

发布时间：2018-12-13 02:42

【摘要】：分别运用总括非均相反应机理和详细非均相反应机理,结合均相反应机理(包括285种气相组分,1 074个气相可逆基元反应)来模拟C_3H_8在CVI工艺条件下炭纤维表面热解炭的沉积过程,进而对实验中的气相组分和热解炭的形成过程进行预测。总括非均相反应机理对炭沉积反应进行了简化处理,气相中的烃组分直接在表面脱氢沉积为热解炭;而详细非均相反应机理则利用表面基元反应来描述热解炭沉积过程,包括66种表面组分和250个表面基元反应。本文以C_3H_8为炭源,N_2为稀释气体,温度1 173~1 323 K、低压(2.6 kPa)和滞留时间为0.5~4s条件下的连续搅拌釜反应器为模型进行模拟,气相组成和沉积动力学两方面的预测与实验结果都较好吻合。计算表明在该设定条件下热解炭的前驱体主要为不饱和小分子(C_2H_2和C_2H_4)和甲基,进而利用这些组分定量解释热解炭的沉积动力学。
[Abstract]:Combined with homogeneous reaction mechanism (including 285 gas phase components), the mechanism of homogeneous reaction and detailed heterogeneous reaction mechanism were used, respectively. 1 074 gas phase reversible unit reactions were used to simulate the deposition process of pyrolytic carbon on the surface of carbon fiber under CVI process, and the gas phase composition and the formation process of pyrolytic carbon in the experiment were predicted. The carbon deposition reaction was simplified by the mechanism of heterogeneous reaction. The hydrocarbon components in the gas phase were directly dehydrodeposited on the surface into pyrolytic carbon. The detailed heterogeneous reaction mechanism uses surface elementary reaction to describe the pyrolytic carbon deposition process, including 66 surface components and 250 surface unit reactions. In this paper, a continuous stirred tank reactor with C_3H_8 as carbon source, N _ (2) as dilution gas, temperature at 1173 ~ (-1) 323K, low pressure (2.6 kPa) and residence time of 0.5 ~ (4) s was used as a model. The prediction of gas phase composition and deposition kinetics is in good agreement with the experimental results. The results show that the precursors of pyrolytic carbon are mainly unsaturated small molecules (C_2H_2 and C_2H_4) and methyl groups under the given conditions, and then the deposition kinetics of pyrolytic carbon can be quantitatively explained by these components.
【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;航天材料及工艺研究所先进功能复合材料技术国防科技重点实验室;
【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】：TB332

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