Abstract
Hydrogenation of tetralin over Pt/Al2O3 and Pt/TiO2-ZrO2 were executed in a bench scale fixed bed reactor under 160-270 °C and 450 psi in the presence or absence of sulfur compounds in feed. The activity was compared by the rate constant of hydrogenation of tetralin, which was considered to follow a first-order kinetic model. In the range of sulfur content from 0 ppm to 30 ppm, the rate constant (kS) inversely proportion to the sulfur content (CS) was observed. Thus, a method to obtain sulfur adsorption equilibrium (KS) was developed by Langmuir-Hinshelwood model. The sulfur adsorption equilibrium constant of Pt/TiO2-ZrO2 and Pt/Al2O3 were 7×106 and 2×107, respectively. Moreover, the heat of adsorption of sulfur could be obtained from the apparent activity energy in the presence and absence of sulfur. The heat of adsorption of Pt/TiO2-ZrO2 and Pt/Al2O3 were -19.4 and -41.0 kJ/gmol, respectively. The results showed that the sulfur desorbed easier while platinum supported on TiO2-ZrO2. Meanwhile, less than 1 ppm sulfur was detected in the product of hydrotreating a 15 ppm S feedstock over Pt/TiO2-ZrO2. These results suggest that Pt/TiO2-ZrO2 exhibits not only a high sulfur tolerance hydrogenation catalyst but also possesses the desulfurization ability.