Effective diffusivity and optimum apparent density of vanadia catalysts for sulfur dioxide oxidation

✍ Scribed by B. Kadlec; R.R. Hudgins; P.L. Silveston

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 981 KB
• Volume: 28
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(77)80028-6

✦ Synopsis

The effective difisivities of air and SOZ in four industrial vanadium pentoxide catalysts were measured at steady-state using helium as the counter diffusing gas. An improved catalyst mounting technique and diffusion cell were employed. The nonsurface component of diffusion was successfully correlated using Bruggeman's model for tortuosity, and 5 based on pore size distribution data or calculated from specific pore volume and surface. However, it was necessary to use flow porosity in place of open porosity. Since the same pore model can be used for the catalytic oxidation Sop, nonreacting flow measurements can be employed to predict effective diffisivities under reaction conditions in this case. With models for the effective diffisivity and the kinetics of the catalytic oxidation of SO*, an optimum apparent density of the catalyst may be determined which gives the maximum rate of reaction per unit volume of catalyst. Calculations are given for the SVD catalyst.