正己烷在Pt/Al_2O_3催化剂上的完全氧化

用外循环无梯度反应器研究了在Pt/Al_2O_3催化剂上内扩散对己烷完全氧化动力学的影响。当催化剂为30—40目时己烷完全氧化在动力学区域进行,当催化剂颗粒增大到4mm时反应在内扩散区域进行,催化剂有效因子在O.14—O.38之间。它表明反应严重地受内扩散阻碍。在氧分压过量时,在动力学区域已烷完全氧化的反应级数为0级,在内扩散区域它变为O.45级。动力学区域的表观活化能为19.OkJ/mol,内扩散区域的表观活化能为10.7kJ/mol,它近似动力学区域活化能及扩散活化能的算术平均值。用试射法及Euler方法计算了已烷在催化剂孔内的分压分布。

THE COMPLETE OXIDATION OF HEXANE OVER Pt/AI_2 O_3 CATALYST

The effect of internal diffusion on the kinetics of the complete oxidation of hexane over Pt/Al_2O_3 catalyst has been investigated i(?) an external circulation gradientless reactor. The complete oxidation of hexane occurred in kinetic region with 30-40 mesh catalyst. When the particle size of catalyst was increased to 4mm, the reaction occurred in internal diffusion region. The effectiveness factors were in the range of 0.14-0.38, indicating that the reaction was strongly affected by internal diffusion. For the complete oxidation of hexane with oxygen the reaction order with respect to hexane was zero in kinetic region and 0.45 in internal diffusion region. The apparent activation energies was 19.0kJ/mol, and 10.7kJ/mol, respectively. The latter value is approximately the arithmetic mean of that for diffusion and that for chemical reaction. The Partial pressure profile of hexane in catalyst pores was calculated by the Shooting method and Euler method for solving ordinary differential equations.