Vacuum residues (VR) are mixtures of extreme complexity, their characterization by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) require fractionation processes to avoid the effect of ionic suppression of compounds with low abundance or low ionization efficiencies. In order to improve this characterization, were evaluated the separation ability of two path of molecular distillation: batch process and continuous mode in two Colombian VRs (VR-P and VR-SF respectively). VR and their fractions were analyzed by APPI FT-ICR MS in positive mode where mass spectra were normalized according to yields of MD processes. According to expected, average molecular weight of residues was higher compared to distillates samples and was found that area under curve of VR can be constructed from the sum of areas of normalized spectrum of fractions. In mass spectra of fractions of VR-P were found new heteroatomic classes: N2, N3, NO2, NOS, O2S, O3 and OS that were no found in VR-P spectrum but in the spectra of MD fractions in continues mode only were found NOS and NS2 classes. So, the major contribution of new heteroatomic classes was found in MD in batch mode. Besides of contribution of new classes in fractions of MD, it was found that it is possible to identify 6400 “new” molecular species with high and low DBE and carbon number, compare to species that were found in VR-P. However the lower quantity of new compounds found in VR-SF (2700) indicated that batch process has a major ability to avoid ionization suppression and consequently, can be a better process in the detailed characterization of vacuum residues.

Improved molecular characterization of petroleum vacuum residues by FT-ICR MS analysis of their molecular distillation fractions

249th National Meeting (2015)

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