Paper Title:
A Realistic Method to Describe the Role of Diffusion in Catalyst Design
  Abstract

The dehydrogenation of diethylbenzene to divinylbenzene is a catalytic reaction. The catalyst for the dehydrogenation was prepared by co-precipitation of iron and chromium hydroxide from nitrate solution, followed by doping with potassium carbonate and drying. To make available the internal surface area of the catalyst for the reactant, the pores must be of the proper sizes to allow the reactant to diffuse and penetrate inside the catalyst pellets. The prepared catalyst was considered as a model for investigating the role of diffusion in catalyst design. In this study, different mechanisms of diffusion, such as Knudsen and bulk, were investigated for the case of diethylbenzene diffusion into the catalyst and it was concluded that the pore sizes should be in a range that permits transitional diffusion (both Knudsen and bulk diffusion). The catalyst grain size can be controlled and varied by acting on parameters such as the speed and time of mixing, type of alkali, temperature and pH. Particle size distribution experiments were conducted for different types of alkali and speeds of mixing in order to characterize the catalyst. The effects of the grain size, formed during co-precipitation, upon the pore size distribution of the catalyst pellet which affects the effective diffusivity were discussed. The pore size distribution of the model catalyst was obtained and the effective diffusivities were calculated by numerical integration of the Johanson-Stewart equation.

  Info
Periodical
Edited by
David J. Fisher
Pages
65-76
DOI
10.4028/www.scientific.net/DDF.294.65
Citation
M. E. Zeynali, "A Realistic Method to Describe the Role of Diffusion in Catalyst Design ", Defect and Diffusion Forum, Vol. 294, pp. 65-76, 2009
Online since
December 2009
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Feng Hua Bai, Yin Xia Zhang, Hai Quan Su, Xue Fen Li, Hui Pan, Xu Zhuang Yang
Abstract:The effect of precursors of Co/γ-Al2O3 catalysts prepared from Co(NO3)2 and...
684
Authors: Gang Li Zhu, Tao Chen, Xue Dong Jiang, Hai Liang Zhang, Bo Lun Yang
Chemical Materials
Abstract:Dehydrogenation process of organic chemical hydrides was improved by modifying the catalyst of nickel-activated carbon (Ni/AC) with lanthanum...
2110
Authors: Takeshi Miki, Yutaka Tai
Abstract:Fe2O3/Al2O3 catalyst was prepared and the catalytic oxidation of toluene over the catalyst was...
101
Authors: Shu Wei Chen, Xiao Fei Jia, Xing Yu Cui, Rui Feng Li
Chapter 8: Energy Saving, Environmental Protection, Low Carbon Ideas
Abstract:This work shows that N2O, which causes global warming, could be effectively utilized as a soft oxidant in the oxidative...
932
Authors: Hai Bin Yu, Jing Cheng Zhang, Jun Nan, Shan Geng, Yu Ting Zhang, Yu Lin Shi, Xiao Long Qu, Hong Guang Liu
Chapter 4: Catalyst, Inhibitors and Reaction
Abstract:Bulk Ni-Mo-W hydrodesulfurization catalysts with high catalytic activity were synthesized via direct precipitation and controlled pH...
604