Characterization of Maya Asphaltene and Maltene by Means of Pyrolysis Application

Abstract

The comparison of the original Maya asphaltene and asphaltene samples obtained after pyrolysis has been performed by different analytical methods: mass spectrometry, infrared spectroscopy, and 13C solid-state magic-angle spinning−nuclear magnetic resonance (MAS−NMR) spectroscopy. The original asphaltene sample has been studied by solution-state 13C and 1H NMR spectroscopy. Besides, outline pyrolysis of the isolated Maya maltene at T > 350 °C was performed. As a result, coke, asphaltene, maltene, and gas products have been obtained. The initial Maya maltene has been studied by thermogravimetric and differential thermal analyses. The results of Maya asphaltene and maltene pyrolysis have been compared and discussed.

Investigation of Island/Single-Core- and Archipelago/Multicore-Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled with High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Archipelago-type structures are preferably cracked at alkyl linkers between two smaller core structures [10,34]. Islandtype structural motifs, however, are known to cleave off alkyl side chains during thermal treatment [34,[59][60][61] resulting in lowly alkylated, highly aromatic cores clustering at the aromatic limit [62][63][64] as well as aliphatic compounds. If the aromatic core of island-type asphaltenes is still evaporable, it is detected during the pyrolysis phase, otherwise, (3) extremely highly aromatic cores (high boiling point) tend to form coke and remain as residue [34,59,60].…”

Asphaltenes: Separations, structural analysis and applications

“…For example, the identical ratio of H to C atoms in asphaltenes varies from 1.0 to 1.3. While O, N and S contents fluctuate in bigger extent according to the literature are O, 0.3%-5.0%; N, 0.6%-3.0%; S, 0.3%-10%; V and Ni present in mg/g levels [11][12][13][22][23][24][25] . Another two common elements in trace amounts are Fe and Mo [26] .…”

“…XRD and NMR founded that, with the temperature increase, L α , d m , total http://engine.scichina.com/doi/10.1016/j.jechem.2018.10.004 carbon number and average alkyl chain length decreased, while f α and aromatic carbon number increased [190] . The heteroatom removal usually contains hydrodesulfurization (HDS) [29,191,192] , hydrodenitrogenation (HDN) [12,191,193] , and hydrodemetallization (HDM) [24,192] , which is not as easy as desirable since the nucleus system remained with and/or without heteroatoms. Singlelump model was more adequate than Langmuir-Hinshelwood (L-H) models for specific asphaltenes [193] .…”

“…The pyrolysis may undergo a multi-step process, so do asphaltenic core and maltene [171,201] . Asphaltene conversion, gas yield, coke formation, S, N-specie reactivity, metal releasing, as well as asphaltene structure and its aromaticity mainly change with temperature and reaction time [24,171,174,202] .…”

Group structure characteristics of the liquid thermolysis products of vitrinites of different ranks

“…One of the reasons for this is a deficiency in information on the composition and structure of the components of heavy hydrocarbon systems, including coal, bitumen, oil shale, etc. In this context, it is of paramount impor tance to study the molecular structure and composi tion of tar-asphaltene substances and their thermal stability, which depends to a certain extent on the con centrations of polycyclic naphthenic and aromatic structures [1][2][3].…”