Performance Evaluation of Certain Commercial Hydrotreating Catalysts in a Pilot Plant Reactor

The performance of different hydrotreating catalysts was evaluated in a pilot plant trickle bed reactor using a feedstock collected from an industrial diesel hydrodesulfurization unit. The feed is a typical blend of straight run diesel fractions from crude distillation units, FCC cycle oils, heavy naphtha, etc. It contains 1.11 wt% of sulfur, 0.12 wt% of nitrogen, and 34.6 wt% of total aromatics. The catalyst samples evaluated in the present work are commercially available high activity new generation catalysts being used in many refineries for diesel hydrodesulfurization application. The experiments were carried out at a constant pressure of 40 kg/cm² and a constant H₂/oil ratio of 200 l/l. Experiments were performed to study the influence of reactor temperature and liquid hourly space velocity on product quality. The reactor temperature was varied from 320-360°C at different liquid hourly space velocities. The liquid hourly space velocity was varied from 1.0 to 2.5 h^-1 at different reactor temperatures. The feed and product samples hydrotreated in the pilot plant reactor were analyzed to determine their physical properties and measure sulfur, nitrogen, olefinic, poly-, di-, monoaromatic, and naphthenic hydrocarbons. Catalyst C was found to have the highest hydrodesulfurization activity among the catalysts studied. The hydrodesulfurization activity of catalyst A and catalyst B are similar. Catalyst D was found to have lower hydrodesulfurization and higher hydrodenitrogenation activity compared to catalyst C.