A pilot reactor study to determine operational factors of the commercial hydrodesulphurization (HDS) catalyst to produce ultra-low sulphur diesel (ULSD)

Abstract

A pilot plant test was carried out using a catalyst from the refinery hydrotreater unit to process blend feed of 70vol% Light Gas Oil – LGO & 30vol% hydrotreated Gas Oil – HDT GO to produce 8ppm ultra-low sulphur diesel (ULSD) product. The impact of changes in process conditions have been studied for catalyst deactivation rate and hydrogen consumption. Test results shown that refinery unit can process such blend feed to reach 8ppm sulphur product by an increase of the reactor bed temperature. However due to higher aromatic content in the blend feed as compare to reference feed LGO, moderate increase in hydrogen consumption was also observed. Catalyst performance was evaluated at 55/42/32bar hydrogen partial pressure (PPH2) to determine catalyst deactivation rate and hydrogen consumption, targeting ULSD product. A decrease of PPH2 from 52bar (which is current operating condition) to 32bar resulted in reduction of H2 consumption but also shows decrease of catalyst cycle length due to higher deactivation rate. Pilot plant test shows that by contriving computational methods and analysis techniques for hydrogen balance & catalyst deactivation rate from the pilot plant test data, it becomes possible to predict catalyst performance in commercial unit.