Effects of reaction temperature on fines deposition during hydrotreating of bitumen-derived light gas oil

Fines deposition is a persistent operational challenge in the hydrotreating of bitumen-derived gas oils, resulting in pressure drop buildup and early reactor shutdowns. Identifying the key drivers of fines deposition is crucial for understanding its mechanisms and developing targeted mitigation strategies. Recognizing temperature as a key hydrotreating process parameter, this study investigated its role in fines deposition using reactor temperature profiles representative of industrial practice. Hydrotreating tests were carried out at temperatures from 350 °C to 390 °C with fines-laden light gas oil in a three-zone trickle-bed reactor. Results showed that under uniform temperature conditions, pressure drop buildup mainly occurred in the upper reactor zones and accelerated significantly as temperature increased. This trend was linked to temperature-driven changes in the fines’ surface characteristics, particularly asphaltene desorption, which reduced oleophilicity and promoted particle settling. At 350 °C and 370 °C, deposition was primarily physical, whereas at 390 °C, it was revealed that incipient dehydroxylation of the fines promoted chemical anchoring to the catalyst’s surface, which caused deactivation. In the case of increasing and dynamic temperature profiles, the fines were distributed across all reactor zones, which delayed severe plugging and thus, these profiles offered extended run times compared to uniform temperature profiles. Overall, the results of this study provide critical insights into the influence of temperature on fines deposition and highlight practical strategies for enhancing catalyst longevity and reactor performance. • Fines deposition causes pressure drop buildup in hydrotreating reactors. • Increasing temperature leads to more fines deposition. • Under uniform temperature conditions, fines accumulate in the reactor’s upper beds. • At 390 °C, chemical interactions between fines and catalyst result in deactivation. • Increasing and dynamic temperature profiles offer better reactor run lengths.