丙烯热解炭过程的气相产物分析和动力学研究(英文)

Gas products and carbon deposition kinetics in chemical vapor deposition from propylene

以丙烯为碳源,在700℃～1200℃进行化学气相沉积热解炭。采用气相色谱和质谱联用对反应过程中的气体产物进行定性和半定量分析,采用磁悬浮天平实时称量反应过程中的固相产物进行动力学研究,在此基础上提出丙烯分解形成热解炭的机理。气相产物的分析结果表明:丙烯热解过程产生30多种芳香化合物,随着温度的升高,主要反应生成物由萘转变为苯;动力学研究结果表明,800℃～1000℃的活化能为137±25kJ/mol,生成乙炔的基元反应控制固相产物的形成。当温度高于1000℃时,沉积行为由气相分子通过边界向固相表面扩散和气相成核共同控制,形成热解炭的主要物质逐渐由苯转变为不饱和碳氢化合物如乙烃,乙烯等。

Gas products and chemical vapor deposition kinetics of pyrocarbon （PyC） formed during pyrolysis of a propylene/argon mixture in the range 700-1200℃ were analyzed by out-line gas chromatography coupled with mass spectrometry and by an in-situ magnetic suspension balance,respectively. More than 30 components were identified. Benzene was the main product,substituting for naphthalene as the temperature increased. PyC was formed with an apparent activation energy of （137±25） kJ/mol,assumed to be controlled by the acetylene-forming reaction from 800℃ to 1000℃. Whereas,above 1000℃,the deposition behavior was representative of a combination between gas phase diffusion from the bulk flow to the solid surface and gas phase nucleation. Reaction models describing homogeneous gas phase PyC deposition reactions were derived. On the basis of these results,a reaction path scheme of PyC formation from propylene was proposed.