Two hydro treating catalysts which are markedly different in terms of textural and physical properties, are investigated and compared in hydrodesulphurization reaction of thiophene added to gas oil. The catalyst attributed (A) is a micro porous and the other catalyst (U), is a mesoporous type. An empirical model of reaction rate was derived for two catalysts in a micro tubular reactor in high pressure. The kinetic parameters were determined in high pressures, i.e. more than 1.2 Mpa, and temperature range of 250 to 320 °C with high space velocity of 5 to 7.5 11(1 The activity tests were carried out on pellet catalysts in different temperatures to derive the effectiveness factor of the catalysts. Using the mathematical modeling of the pellet and reactor Thiele modulus, effective diffusivity and tortusity factor of the catalysts were calculated. It is inferred that catalyst (U) with spherical shape and higher pore size is more suitable for HDS reaction of gas oil than catalyst (A). The kinetic and physical properties of these catalysts can be used for modeling of HDS process in pilot plant scales.
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