Application of variable reaction order kinetics to predict hydrotreating catalyst deactivation rate

PETR 64

Omer Refa Koseoglu, Omer.koseoglu@aramco.com, Research and Development Center, Saudi Aramco, Box 62, Dhahran, 31311, Saudi Arabia and Hamad Al-Sobhi, hamad.sobhi@aramco.com, Rabigh Refinery, Saudi Aramco, Operations and Engineering Division, Rabigh, Saudi Arabia.
A kinetic study was carried-out on the Rabigh Refinery Hydrotreating Unit data to determine the catalyst deactivation rate and process performance. The study shows that hydrodesulfurization reactions can be best explained by the variable reaction order kinetics due to changing feedstock composition. The kinetic study results in a catalyst deactivation rate of 1.3ºC/month. The ASTM D85 distillation 85 V% point improvement is about 5ºC. Refinery economics favored processing more heavy gas oils at the expense of slightly higher catalyst deactivation rate and a lesser affinity to product quality.