Petroleomic Characterization And Hydrodesulfurization Of FCC Slurry

Catalytic cracking slurry?FCC slurry?is the main by-product of fluid catalytic cracking process.In recent years,the output of FCC slurry is getting larger and larger.How to make rational use of FCC slurry has always been a problem that plagues the industry.Because catalytic cracking slurry belongs to the category of heavy oil,The composition and structure are complex.A comprehensive understanding of the composition of FCC slurry and the law of compound conversion before and after hydrogenation can provide theoretical guidance for more rational and efficient utilization of FCC slurry,..In this paper,the whole molecular composition of FCC slurry and the change of molecular composition before and after hydrogenation are studied.A new method for analyzing sulfides and aromatic hydrocarbons in heavy oil is also developed.?1?The fluid catalytic creaking slurry decant oil and its fractions were characterized by a high resolution Orbitrap mass spectrometry with various ionization techniques,such as positive-and negative-ion ESI,atmospheric photoionization,as well as chemical derivatizations.Molecular composition results obtained from various methods were combined and normalized by elemental composition of FCC decant oil and its fractions.A total of 7001 molecules in 18 class species found in FCC decant oil,were quantified.Aromatic hydrocarbons were the most abundant,accounting for 49.6 wt%of FCC decant oil.The non-basic N₁O₃ class species had a minimum content of 0.03 wt%.The concentration of assigned molecules ranges from 2.0?10^-3?g/g for C₂₂H₁₅N₂ to 2.1?10⁴?g/g for C₁₈H₁₂.?2?The molecular composition of heteroatom compounds,especially sulfur compounds of FCC slurry before and after hydrogenation was studied in detail.The content of benzonaphthylthiophene compound in oil slurry is the highest,and its hydrogenation conversion rate is high.Benzo-naphthothiophene is easily saturated to form tetrahydrobenzonaphthothiophene.The most difficult hydrogenation compound in FCC slurry is 2,4,6,8-tetramethyldibenzothiophene,hydrogenation conversion rate of 0,concentration in the slurry of 87 ppm,2,4,6,8-tetra methyldibenzothiophene is extremely difficult to remove,and hydrogenation of phenanthroline series compounds is relatively easy.After the weak hydrogenation process,the condensation degree of the nitrogen-containing and oxygen-compounds reduced,which is beneficial to the production of high-quality needle coke.?3?A simple selective methyl derivatization method for the analysis of sulfides in petroleum was presented.Only methyl iodide without the use of promoter,such as Ag BF₄,is added to the petroleum sample to selectively ionize sulfides for direct?i.e.,online liquid chromatography?LC-MS?or liquid introduction by infusion?positive-ion electrospray mass spectrometry analysis.The sulfides composition obtained is consistent with that of isolated sulfide fraction from the CH₃I/Ag BF₄ methylation/demethylation method.Compared to the CH₃I/Ag BF₄ method,the CH₃I method has the following benefits:it is convenient and quick,because it does not need a promoter for methyl ion addition onto the sulfur atom and time-consuming separation processes to remove the promoter that can suppress other ions generated in ESI.Hence,it avoids the inaccuracy of the compositional analysis caused by the loss of sulfide compounds from the separation processes.The method is validated by model compounds and has been successfully applied to the analysis of sulfides in diesel,VGO,crude oil,and distillation residue.?4?A mass spectrometric analysis method for petroleum aromatic hydrocarbon molecular composition based on derivatization reaction was developed.the aromatic hydrocarbons in VGO were sulfonated to highly polar sulfonates which were analyzed by-ESI FT-ICR MS.Compared with the traditional APPI ionization method,the composition results analyzed by sulfonation reaction combined with ESI FT-ICR MS could accurately reflect the composition of aromatic hydrocarbons in VGO samples.