PTQ Q4 2024 Issue

Handling complex hydrocarbon molecules

Growing interest in processing heavy oils with high nitrogen content has created a need for pretreatment catalysts with higher HDN and HDS activity

Xavier E Ruiz Maldonado and Ryan Jesina Topsoe Inc, USA Michal Lutecki Topsoe A/S, Denmark

T o help refiners remove harmful environmental pol - lutants while optimising system stability and prof - itability, a matrix of hydrocracking pretreat, mild hydrocracking, and FCC pretreat (or gasoil) catalysts with the maximum accessible particle surface area is required to maximise catalyst activity. This can be seen in refineries across the US, where processing units are challenged with a wide range of operating conditions. These operational parameters are comprised of varying hydrogen partial pressures and diverse feedstock types, including vacuum gasoil (VGO), heavy cracked feedstock, FCC slurry, and synthetic crude-derived feedstock. Refiners must also have the flexibility to meet a wide array of prod - uct specifications, spanning both high and low hydrodes - ulphurisation (HDS) and hydrodenitrogenation (HDN) conversion levels, maximum polynuclear aromatics (PNA) saturation/volume swell, and middle distillate conversion. Tailored solutions are needed to meet each facility’s unique pain points that must be overcome in the optimisation of refinery processes, product specifications, and economic performance.

enhance the hydrogenation activity of NiMo BRIM catalysts to further increase catalytic performance. This involved utilising an improved alumina support combined with advanced metals impregnation techniques, which resulted in Topsoe’s HyBRIM generation of catalysts. The advanced metals impregnation techniques for HyBRIM catalysts result in a higher degree of active metals utilisation when compared to BRIM catalysts. This is due to the combined effect of lower stacking and highly dispersed MoS₂ nano-slabs, as shown in Figure 1 . In other words, HyBRIM technology can disperse a higher number of nano- slabs due to a reduced interaction between the metal slab and the carrier, which increases HDS activity via both the direct and the hydrogenation routes. Heavy gasoil diesel applications Following the full development of HyBRIM NiMo catalysts, research was conducted to extend this technology to CoMo catalysts. This effort yielded significant results, leading to the development of Topsoe’s new generation of CoMo HyBRIM catalysts, which are suitable not only for heavy gasoil applications but also for diesel applications. An

Enhancing hydrogenation activity In the 2000s, research¹ , ² and develop - ment revealed the presence of basal plane CoMo and NiMo sulphided slabs that shed light on the final step of the hydrogenation route/mechanism. This was revealed using advanced, scan - ning tunnelling electron microscopes. This advancement resulted in the pro - duction of more resilient heterogene - ous catalysts for all hydroprocessing applications. The discovery of active sites for HDS were later designated by Topsoe as BRIM sites. Since then, BRIM technol - ogy has been refined and utilised to introduce the first generation of NiMo and CoMo BRIM catalysts for the hydro - processing industry. Topsoe’s research teams and specialists have strived to advance formulation optimisations to

Figure 1 Illustration of alumina-supported catalysts (left), BRIM, and HyBRIM optimised dispersed slabs structures (right)

PTQ Q4 2024