Thermal decomposition behaviour and structural characteristics of asphaltenes

Calemma, Vincenzo; Rausa, R.

doi:10.1016/s0165-2370(97)00016-8

Cited by 20 publications

(24 citation statements)

References 14 publications

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“…This deposit can be assigned to carbonized species formed during pyrolysis, e.g., graphite. Literature shows that the yield of volatile matter in the pyrolysis phase correlates with the aliphatic content in petrochemicals, and therefore, a high proportion of the mass loss will be caused by dealkylation of aromatic species . In summary, the hypothesis that the interlaboratory asphaltene sample does not contain significant amounts of volatile or semi-volatile species can be stated and is in agreement with the literature for other asphaltenes …”

Section: Resultssupporting

confidence: 87%

“…Isobaric species for this series can be alkylated cycloalkanes with 1 saturated ring, which were found only in minor abundance in the GC pyrograms and are less common as stable products in pyrolysis. 59,63 The average alkene length estimated with the universal soft SPI is congruent to the pyrolysis GC data obtained with the universal hard electron ionization, although the photoionization cross section has to be taken into account. Fortunately, in SPI, the cross sections range only between a factor of 2 and 3 within one compound class.…”

Section: Energy and Fuelssupporting

confidence: 67%

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Combination of Different Thermal Analysis Methods Coupled to Mass Spectrometry for the Analysis of Asphaltenes and Their Parent Crude Oils: Comprehensive Characterization of the Molecular Pyrolysis Pattern

et al. 2017

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In this study, the asphaltene and corresponding crude oil, distributed within the Asphaltene Characterization Interlaboratory Study for PetroPhase 2017, were characterized on the molecular level. For this purpose, three different thermal analysis mass spectrometry hyphenations with five diverse ionization techniques varying in selectivity were deployed: (1) thermal desorption/pyrolysis gas chromatography electron ionization (TD/Pyr–GC–EI–QMS), (2/3) thermogravimetry single-photon/resonance-enhanced multiphoton ionization time-of-flight (TG SPI/REMPI TOF–MS), and (4/5) thermogravimetry atmospheric pressure photo-/chemical ionization ultrahigh-resolution mass spectrometry (TG APPI/APCI FT-ICR MS). For the investigated C7 asphaltene, no mass loss was detected at <300 °C and the pyrolysis phase was dominant, whereas the parent crude oil exhibits a high abundant desorption phase. At roughly 330 °C, pyrolysis begins and mass loss as well as complex mass spectrometric patterns were recorded. The resulting information on the effluent gained by the different soft ionization mass spectrometric approaches was combined with the GC–EI–MS data for structural cross-evaluation. We showed that the combination of the applied techniques leads to a more comprehensive chemical characterization. For the asphaltene, TG SPI TOF–MS shows high abundances of alkanes, alkenes, and hydrogen sulfide during pyrolysis. TG REMPI TOF–MS is selective toward aromatics and reveals clear patterns of polyaromatic hydrocarbons (PAHs) and minor amounts of nitrogen-containing aromatics tentatively identified as acridine- or carbazol-like structures. GC–EI–MS provides information on the average chain length of alkanes, alkenes, and PA(S)H. Both atmospheric pressure ionization techniques (APPI and APCI) hyphenated to FT–MS showed CHS (in particular, benzothiophenes) and CH as dominant compound classes, with an average number of condensed aromatic rings of 2–4. Combining the information of all techniques, including the average asphaltene mass obtained by field desorption experiments and aromatic core size received by collision-induced dissociation, the archipelago-type molecular structure seems to be dominant for the investigated asphaltene.

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Section: Resultssupporting

confidence: 87%

Section: Energy and Fuelssupporting

confidence: 67%

Combination of Different Thermal Analysis Methods Coupled to Mass Spectrometry for the Analysis of Asphaltenes and Their Parent Crude Oils: Comprehensive Characterization of the Molecular Pyrolysis Pattern

et al. 2017

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“…The difficulty remained of determining whether the tested oil samples were from cracking or just diluted by condensed light components. When considering the reaction kinetics of the hydrocarbons, especially for producing the heavy heteroatom-containing O, N, and S components, the oxidation kinetics and the reaction products are severely influenced by their functional groups and molecular structures . Carbon bond cleavage will occur through breaking either the alkyl side chains on the ring or aliphatic bridges between aromatic and naphthenic units .…”

Section: Introductionmentioning

confidence: 99%

“…When considering the reaction kinetics of the hydrocarbons, especially for producing the heavy heteroatom-containing O, N, and S components, the oxidation kinetics and the reaction products are severely influenced by their functional groups and molecular structures. 9 Carbon bond cleavage will occur through breaking either the alkyl side chains on the ring or aliphatic bridges between aromatic and naphthenic units. 9 The temperature is another key factor to determine the reaction pathway.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Acidic Compounds in Crude Oil during In Situ Combustion

Zhao¹,

Sun²,

Fang³

et al. 2017

Energy Fuels

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In situ combustion (ISC) process has drawn more and more attention in the development of heavy oil reservoirs as a result of its high recovery efficiency. Although numerous studies have been reported that oil properties exhibit significant changes during the combustion process, the reaction mechanisms and evolution of oil components are still not well understood. In this work, the compounds of produced oils collected from a three-dimensional simulated production model (container) at different duration times after combustion being initiated and the original oil were characterized at the molecular level using gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), and high-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Both aromatic and acidic components were analyzed. The aromatic components showed relatively more stable characteristics than those of acidic components, and no obvious changes in aromatic compound distributions were observed by the positive ion atmospheric pressure photoionization (APPI) FT-ICR MS analysis. Small aliphatic acids were detected in the ISC oils, which were responsible for the high total acid numbers (TANs). The acidic O x (x = 1–3) compounds, which have major contributions to the increase in TAN, were generated in greater abundances compared to that of the original crude oil. The carbon number distributions of the O1 and O2 classes in the produced oils significantly shifted to a lower carbon number region, with the dominant distribution from 15–40 at the initial state to 10–30 at the longest duration time. The double bond equivalent (DBE) values decreased during the combustion process. The generated acidic O1 components with DBE values less than 4 were also found in negative ion electrospray ionization (ESI) analysis, indicating the oxidation of hydrocarbons to alcohols.

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“…This is because asphaltenes are assumed to be a molecular "archive" for the associated source-rock kerogen (Pelet et al, 1986). Pyrolysis experiments have shown that kerogens and asphaltenes generally show similar structural characteristics (Behar and Pelet, 1985;Calemma and Rausa, 1997;di Primio and Horsfield, 1996;Dieckmann et al, 2002;Eglinton et al, 1991;Horsfield et al, 1991;Larter, 1984;Solli and Leplat, 1985). Therefore asphaltenes are thought to be moieties of kerogen generated during its early thermal evolution, and to contain structural and maturity-related information concerning the sourcerocks from which the kerogen was generated Huc et al, 1984;Nali et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Predicting the Timing and Characteristics of Petroleum Formation Using Tar Mats and Petroleum Asphaltenes: A Case Study From the Northern North Sea

Keym

Dieckmann

2006

J Petroleum Geol

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The Northern Viking Graben area in the Norwegian North Sea was studied in order to investigate the petroleum formation characteristics of the Upper Jurassic Draupne Formation. In this area, the organofacies of the Draupne Formation, and consequently its petroleum generation characteristics, show significant variations. These variations represent a major risk, particularly in the context of basin modelling studies. Therefore, tar-mat asphaltenes, oil asphaltenes and sourcerock samples from this area were studied in order to evaluate the use of migrated asphaltenes from petroleum reservoirs and tar mats in basin modelling. The samples were studied using bulk kinetic analysis, open-system pyrolysis -gas chromatography and elemental analyses, and the results were integrated into a basin modelling study. The results from these different sample materials were compared both to each other and to natural petroleum, in order to assess their significance for future petroleum exploration activities.We show that in cumulative petroleum systems, the transformation characteristics of the asphaltenes incorporate those of the individual source rock intervals which have contributed to the relevant reservoir system. Thus, the petroleum formation window predicted by the use of asphaltene kinetics is broad, and covers the majority of the formation windows predicted from the individual source rock samples. In addition, the molecular characteristics of asphaltene-derived hydrocarbons show that compositional characteristics, such as aromaticity, correspond more closely to natural oils than to the respective source-rock products.Our results confirm that the heterogeneous nature of the Draupne Formation results in a significantly broader petroleum formation window than is conventionally assumed. We propose that oil and tar-mat asphaltenes from related reservoirs represent macromolecules which account for this heterogeneity in the source rock, since they represent mixtures of charges from the different organofacies. One conclusion is that the use of oil and tar-mat asphaltenes in kinetic studies and compositional predictions may significantly improve definitions of petroleum formation characteristics in basin modelling.

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Thermal decomposition behaviour and structural characteristics of asphaltenes

Cited by 20 publications

References 14 publications

Combination of Different Thermal Analysis Methods Coupled to Mass Spectrometry for the Analysis of Asphaltenes and Their Parent Crude Oils: Comprehensive Characterization of the Molecular Pyrolysis Pattern

Combination of Different Thermal Analysis Methods Coupled to Mass Spectrometry for the Analysis of Asphaltenes and Their Parent Crude Oils: Comprehensive Characterization of the Molecular Pyrolysis Pattern

Evolution of Acidic Compounds in Crude Oil during In Situ Combustion

Predicting the Timing and Characteristics of Petroleum Formation Using Tar Mats and Petroleum Asphaltenes: A Case Study From the Northern North Sea

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