hrvatski

Priprema Ni/Al2O3 katalizatora impregnacijom

The performance of supported catalyst depends critically on its active ingredient within support. For those catalyst prepared by impregnation of support with solution containing the appropriate metal precursor, the internal distribution of the catalytically active components within support can be depend upon the duration of the impregnation and concentration of impregnant solution. The work investigates the effect of time and concentration od NiCl2 in impregnant solution on the internal distribution of nickel in -Al2O3. A model of impregnation is developed that includes a mathematical description of all processes. From the simulation results it was concluded that the concentration profile of precursor of catalytically active ingredient inside support depends on the initial concentration of impregnant solution. The results indicate that the distribution of nickel chloride inside the -Al2O3 pellet is uniform as long as the initial concentration of NiCl2 in impregnant solution is small. However, by higher concentrations the active ingredient is absorbed near the outer surface of support. The activity of prepared Ni/Al2O3 calcined and noncalcined was tested using benzene hydrogenation as a model reaction. The obtained results reveal that the catalyst activity increases with the increase of nickel concentration, especially in the case of catalyst calcination. However, the influence of calcination on catalyst activity is more significant with higher nickel loading on support. This fact can be explained by low concentration of nickel aluminate which is produced in reaction between nickel oxide and alumina, and which cannot be easily reduced to catalytically active form of nickel.

Priprema katalizatora impregnacijom; Matematički model impregnacije

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