【摘要】 本文讨论了均匀独立失活催化反应系统中内扩散效应对圆柱孔模型催化剂活性的影响,探讨了 n 级反应、m 级失活系统中有效因子和西勒模数的定量关系。研究结果表明,在失活存在下的非稳态催化过程中,可以定义一个新的失活西勒模数来表征内扩散效应对反应速率和失活速率的影响,对于均匀独立失活的圆柱孔催化剂模型而言,失活西模勒数的通式为 h_dn=L■。对内扩散存在下催化剂失活动力学的进一步分析得到,内扩散阻力将使多孔催化剂的寿命得以延长,对 n 级反应一级失活的系统,强内扩散区域里的催化剂失活速率常数仅是无扩散影响区域中的一半。更多还原

【Abstract】 The research and development of catalysts,the design and operation of catalytic reactors are complicated by the phenomenon of catalyst deactivation which is af- fected by various factors. In the present study,the effect ot internal mass transfer resistance in the cata- lytic reaction system of uniform independent deactivation on both reaction and de- activation rates of straight cylindrical pore model has been discussed.In addition, the quantitative relations between effectiveness factor and Thiele modulus in se- cond,zero and first order reaction and m-th order deactivation system have been correlated. The results revealed that we could coin a new modulus,i.e.Deactivation Thiele Modulus h_dn=L((2kⁿC₀^n-1α)/(rD_eff)^1/2（for cylindrical pore）,to describe the effect of inter- nal diffusion on both reaction and deactivation rates in the unsteady state cataly- tic process with catalyst deactivation.It was similar to the steady state catalytic pro- cess for non-deactivating system with Thiele modulus to express the influences of internal diffusion on reaction rate of porous catalyst pellets.The effect of internal diffusion on deactivation rate of uniform independent system was slightly affected by catalyst geometries.For different reaction order systems,the sequence of influ- ence of pellet internal diffusion on both steady state and unsteady state systems were the same.However,for the latter case,with an increase in dimensionless time the Change of effectiveness factor was smoothed down as Thiele modulus varied. Furthermore,catalyst under the influence of internal diffusion resistances had a longer life than those with diffusion-free deactivation systems.For n-th order reaction and first order deactivation system,the deactivation rate constant in strong pore diffusion region was one-half the deactivation rate constant in the diffu- sion-free region.更多还原