Formation of phase composition of petroleum bitumen according to data of temperature modulated differential scanning calorimetry

Frolov, I. N.; Yusupova, T. N.; Зиганшин, Марат А.; Okhotnikova, E. S.; Firsin, A. A.

doi:10.1007/s10973-017-6779-1

Cited by 11 publications

(5 citation statements)

References 26 publications

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“…Asphaltenes create over a relatively long-time aggregative solid structurally amorphous (liquid) phase as a result of relaxation structural glass transition by a spinodal thermodynamic phase separation mechanism. 53 During the heating process of asphalt, the heat flow curve of MDSC shows the existence of high enthalpy of melting and denitrification at high temperatures, indicating the formation of a disordered phase structure in asphalt, and the enthalpy of melting depends on the content of wax in asphalt. 54 In Figure 12, we analyzed the structural effects of the asphalt phase transition by analyzing the peak migration of the D band and G band peaks.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…Saturated hydrocarbons form an aggregative solid structural crystalline phase in accordance with the laws of structural phase transitions and the nucleation mechanism of thermodynamic phase separation. Asphaltenes create over a relatively long-time aggregative solid structurally amorphous (liquid) phase as a result of relaxation structural glass transition by a spinodal thermodynamic phase separation mechanism . During the heating process of asphalt, the heat flow curve of MDSC shows the existence of high enthalpy of melting and denitrification at high temperatures, indicating the formation of a disordered phase structure in asphalt, and the enthalpy of melting depends on the content of wax in asphalt …”

Section: Resultsmentioning

confidence: 99%

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Variable-Temperature Raman Spectroscopy Study of the Phase Transition Mechanism in Asphalt Binders

Qiu

Liu

et al. 2023

Energy Fuels

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To better understand the mechanism of precipitation and dissolution of the crystalline wax in asphalt, it is necessary to investigate the phase transition process of asphalt at different temperatures. Variabletemperature Raman spectroscopy has been employed to analyze the phase transition properties of eight asphalt binders from the SHRP material reference library. More abundant Raman spectral structure information is obtained by introducing silver nanoparticle colloids (Ag NPs) as a surfaceenhanced Raman scattering (SERS) substrate to quench the selffluorescence. The findings show that Raman spectroscopy can effectively identify different aging states of asphalt according to characteristic peaks. In the temperature range of 20−100 °C, three areas of the Raman spectrum, including 500−1200, 1300−1800, and 2500−3000 cm −1 , indicate that the asphalt has transformed from an ordered phase to a disordered phase and to a liquid phase. The order parameters are selected to represent the change of ordered and disordered structures in asphalt. The phase transition occurs mainly from the changes in the intensity and frequency of the Raman crest related to the crystal structure and distorted conformation. The temperature range of phase transitions from an ordered to a disordered range of asphalt has an obvious correlation with the wax melting point of asphalt, and the disorder degree and molecular defects of asphalt are also positively correlated with the wax content in asphalt.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Variable-Temperature Raman Spectroscopy Study of the Phase Transition Mechanism in Asphalt Binders

Qiu

Liu

et al. 2023

Energy Fuels

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“…The physical and mechanical properties of petroleum bitumen are defined by its microstructure, which depends on structural phase transformations and the temperature–time conditions of its formation. Therefore, in recent decades, a great number of researchers have devoted their work to the investigation of bitumens by differential scanning calorimetry (DSC). − DSC can be used to analyze various thermal processes and phenomena in materials. A performance that is especially relevant for bitumen is the crystallization fraction (CF) content. , Usually, on the DSC heating curve of bitumen, the glass transition is followed by an exotherm of cold crystallization, which is then followed by a broad endotherm due to the dissolution of the CF. − The area of this endotherm is considered to be directly proportional to the CF content.…”

Section: Introductionmentioning

confidence: 99%

“…Typical curves of bitumen DSC analysis: (a) heating (3 °C·min –1 ) curve of unannealed sample; (b) heating (3 °C·min –1 ) curve of as-received sample; (c) curve obtained at rapid cooling (15 °C·min –1 ).…”

Section: Introductionmentioning

confidence: 99%

“…However, the thermal history of the bitumen sample has a critical influence on the DSC result. The heating curves in parts a and b of Figure 1 (obtained during preparation 3 ) exhibit significant differences in the shape of their profiles: on curve a, which is for an unannealed sample (without a thermal history), a single endothermic peak is observed instead of the two distinct peaks on curve b, which is for an as-received sample. The dissolution enthalpy, ΔH, is calculated easily for curve a using a straight baseline.…”

Section: Introductionmentioning

confidence: 99%

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Interpretation of Double-Peak Endotherm on DSC Heating Curves of Bitumen

et al. 2020

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Since the late 1960s, differential scanning calorimetry (DSC) has been used to characterize petroleum bitumen, in particular, for the determination of the crystallized fraction (CF) content. This procedure is based on the construction of a baseline after identifying the CF dissolution endotherm on the heating curve. However, many bitumens commonly exhibit double-peak endotherms during a DSC heating scan. In this case, the task of constructing the corresponding baseline does not have a unique solution because the interpretation of the heat flow profile is ambiguous. Several interpretations have been proposed earlier to explain the origins of the double-peak endotherm. However, the double-peak endotherm is currently still not fully understood, and a comprehensive consensus has not been achieved. If the determination of the baseline location is incorrect, the CF content can be over- or underestimated by 20–30%. In the current work, double-peak endotherm behavior was investigated by temperature modulation DSC. All of the earlier explanations were critically considered. The origin of the double-peak endotherm was discussed in detail, and a probable descriptive model for the formation of the double-peak endotherm was suggested. The endotherm pattern is assumed to be governed by three overlapping thermal events: a broad endothermic background and a twin “recrystallization exotherm–dissolution endotherm” pair. The onset of the recrystallization exotherm and the intensity of both events depend on the annealing temperature and time. The study promotes a better understanding of the relationship between the thermal effects on the DSC curves and the structural changes of bitumen. A correct interpretation of the double-peak endotherm can provide a more exact determination of the CF content in bitumen.

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A review on the application of differential scanning calorimetry (DSC) to petroleum products

Khoshooei

Fazlollahi

Maham

et al. 2019

J Therm Anal Calorim

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Formation of phase composition of petroleum bitumen according to data of temperature modulated differential scanning calorimetry

Cited by 11 publications

References 26 publications

Variable-Temperature Raman Spectroscopy Study of the Phase Transition Mechanism in Asphalt Binders

Variable-Temperature Raman Spectroscopy Study of the Phase Transition Mechanism in Asphalt Binders

Interpretation of Double-Peak Endotherm on DSC Heating Curves of Bitumen

A review on the application of differential scanning calorimetry (DSC) to petroleum products

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