Detailed Mechanistic Studies Of Hydroprocessing Catalysts On Real Feeds For Ultra-Low-Sulfur Diesel Production

Quite a few gaps exist in between academic studies and industrial needs in the field of hydroprocessing. Many rooted in the difference of model compounds versus real feeds, and kinetic studies at low conversion versus rate-limiting factors occurred only at high conversion. In this study, we developed a detailed mechanistic model to decouple a few key kinetic components (rate/order with respect to organosulfur species and H-2 partial pressure) using real feeds at high conversion (90%+) for ultra-low-sulfur diesel (ULSD) production. With the advancement in 2D sulfur gas chromatography with a resolution down to 5 ppm S, we were able to quantify each organosulfur species (e.g., 2,4,6-trimethyl dibenzothiophene) and calculate the rate constant both on an absolute scale and relative to the total sulfur conversion to derive a full mechanistic picture of the rate-limiting step under ULSD (<10 ppm) production process conditions.