A three-dimensional semi-quantitative method to monitor the evolution of polycyclic aromatic hydrocarbons from vacuum gas oil feedstocks to lighter products

Formation and accumulation of polycyclic aromatic hydrocarbons (PAHs) are responsible major topical issues related to the conversion petroleum vacuum gas oils (VGOs) in transportation fuels through hydrocracking process. To achieve an efficient management these hydrocarbons, a detailed semi-quantitative description PAHs contained VGOs was provided by three-dimensional off-line analytical approach based on centrifugal partition chromatography (CPC), supercritical fluid (SFC) high-resolution mass spectrometry (HRMS). As result, well-organised CPCxSFC chromatograms relevant separation according both unsaturation level (DBE) alkylation degree. This dedicated methodology allowed semi-quantification having DBE superior 12. For first time, were quantified six allowing highlight differences composition depending origin samples. Then, evolution PAH concentration monitored during hydrotreating processes. hydrotreated/hydrocracked (HDT/HCK) products, their sulphur nitrogen contents low enough make possible directly SFC/HRMS. An observed when recycle stream from unconverted oil HDT reactor applied. work demonstrates that valuable data could be obtained leading step forward overall understanding process native VGO feedstocks HDT/HCK products.