(701c) Understanding Catalytic Impacts on Vacuum Gas Oil (VGO) Hydrotreating Using Electrospray Ionization-Ion Mobility-Mass Spectrometry (ESI-IMMS)
Vacuum gas oil (VGO) is a complex and challenging petroleum feedstock containing high double bond equivalent (DBE) and polycyclic aromatic species with heteroatoms like nitrogen and sulfur. The presence of these heteroatoms in hydrotreated VGO has great impact including high fouling rate to downstream hydroprocessing processes for making high-value nitrogen and sulfur-free products. Analyzing the composition of VGO is currently a challenge due to the complexity of petroleum-derived hydrocarbons. Analytical methods are increasingly more important as refining utilizes more diverse petroleum feedstocks. In this work, ion-mobility mass spectrometry (IMMS) is used to understand the effect of different hydroprocessing catalysts on the efficiency of nitrogen removal from VGO feedstocks. Analysis of different VGO samples before and after hydrotreating was done using high-resolution positive ion electrospray ionization IMMS. IMMS measurements demonstrated that catalytic hydrotreating altered the overall composition of the VGO samples, removing undesired heteroatom containing compounds. IMMS measurement also revealed different nitrogen residues in hydrotreated VGO products over varying catalysts, indicating that different catalysts had complementary outcomes for removing nitrogen containing compounds. Overall, the IMMS results demonstrate that the efficiency of nitrogen removal can be improved by modifying hydrotreating catalyst systems for diverse and changing VGO feedstocks.