用于N_2O一步氧化苯制苯酚的Fe-ZSM-5催化剂的积碳及再生研究

考察了Fe-ZSM-5分子筛催化剂对N_2O一步氧化苯制苯酚反应的催化性能以及催化剂的积碳和再生过程。通过TG分析得出,在不同空速下,65min内催化剂上的积碳量(质量分数)都接近5%。催化剂的活性评价结果表明,不同空速下形成的积碳对催化剂活性的影响不同,高空速下形成的积碳更易使催化剂失活,低空速下形成的积碳对催化剂活性的影响相对较小。采用非等温法研究了失活Fe-ZSM-5分子筛催化剂的烧炭动力学,得出了烧炭动力学方程,其中烧炭活化能为138.15kJ/mol,烧炭反应级数为7.2。分析结果表明,烧炭过程中的失重量变化率对烧炭速率影响极大,内扩散是烧炭反应的控制步骤。

Coke on Fe-ZSM-5 Zeolite Catalyst for One-Step Oxidation of Benzene with N2O to Phenol and Its Regeneration

Catalytic performance of Fe-ZSM-5 zeolite catalyst in one-step oxidation of benzene with N_2O to phenol was investigated.Coke forming during the reaction under different space velocities and regeneration behavior of the deactivated catalyst were studied.The total amount of the coke measured by TG method approached to 5 %(w)in the reaction for 65 min under the different space velocities. Result of the catalyst evaluation showed that the coke formed under the different space velocities had different impact on the catalyst performance.The coke formed under high space velocity deactivated catalyst more easily,while the that formed under the low space velocity less affected the catalyst performance.Coke combustion kinetics on deactivated Fe-ZSM-5 zeolite catalyst was studied by nonisothermal method and coke combustion kinetic equation was obtained.The corresponding activation energy and the reaction order were 138.15 kJ/mol and 7.2,respectively.The mass loss change ratio for the coke combustion obviously influenced coke combustion rate and internal diffusion was the control step of the coke combustion.