Petroleum Heavy Ends Stability:  Evolution of Residues Macrostructure by Aging

Scarsella, Marco; Mastrofini, D.; Barré, Loı̈c; Espinat, D.; Fenistein, Denis

doi:10.1021/ef980238x

Cited by 15 publications

(5 citation statements)

References 43 publications

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“…It has been shown [12,13] that ageing produces fundamental modifications in the colloidal structure of both vacuum residues and their maltenes fractions shifting all the solubility classes (asphaltenes, resins and saturates plus aromatics) towards the preceding, adjacent less soluble class. However, in contrast to the previous findings, the macrostructure of asphaltenes both in solutions and in a vacuum residue was found not being representative of the age hardening process, in spite of the fact that the content of asphaltenes increased and the ratio of resins, aromatics and saturates against asphaltenes decreased being strongly dependent on temperature ranges [14]. The chemical changes during ageing of several bitumens have been found to include the formation of carbonyl compounds and sulfoxides, and to increase in amount of large molecular associations and polydispersity [15].…”

Section: Introductioncontrasting

confidence: 99%

Ageing of Kukersite Thermobitumen

Sokolova¹,

Tiikma²,

Bityukov³

et al. 2011

Oil Shale

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Ageing of the mix of thermobitumen and oil (TBO) formed at low-temperature pyrolysis of kukersite in autoclaves was studied, and the effect of pyrolysis conditions on the share of fractions soluble in hexane, benzene and tetrahydrofurane was described. The results reveal a decrease in the total weight of TBO and solid residue at storage. During a month of ageing in open air the additional weight loss of the initial organic matter reaches 10-15%. At that, the yield of TBO decreases and that of the solid residue increases. The fractions of TBO soluble in hexane (maltenes + oil) and in benzene (asphaltenes) decrease, and the fraction soluble in tetrahydrofurane (pre-asphaltenes) increases. The initial yields of hexane and benzene solubles depend on the degree of TBO secondary cracking determined by the pyrolysis conditions. The share of the fraction soluble in hexane increases with pyrolysis temperature and duration and attains 40-50% from the initial organic matter on account of decomposition of asphaltenes concurred with decrease in the total yield of TBO to 60-70% because of gas and coke formation.

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Section: Introductioncontrasting

confidence: 99%

Ageing of Kukersite Thermobitumen

Sokolova¹,

Tiikma²,

Bityukov³

et al. 2011

Oil Shale

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“…One reason could be that the molecular weight of the newly formed asphaltenes is likely smaller than that for those native asphaltenes in the untreated oil. Another reason could be ascribed to the lack of colloidal structuring in freshly treated loads, because aging has been identified as a factor that has a key role in determining the colloidal structure and stability of asphaltenes, as determined in petroleum heavy ends and bitumen. , …”

Section: Resultsmentioning

confidence: 99%

Lowering the Viscosity of Doba−Chad Heavy Crude Oil for Pipeline TransportationThe Hydrovisbreaking Approach

et al. 2004

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This study was instigated in view of the recent commercial exploitation of the Doba oil field in landlocked Chad, which is a region from which crude oil is extracted and expected to be routed to the Atlantic shore through pipeline transportation. Thus, nonisothermal kinetic hydrovisbreaking tests of Doba crude oil were conducted in a mechanically stirred baffled autoclave reactor under various conditions to alter the rheological properties of the treated crude. The crude hydrovisbreaking kinetics was modeled based on the four-parameter reaction severity concept (ω, γ, E, β o ), as a function of the conversion in polyaromatics and polar maltenic subfractions. The hydrovisbreaking of Doba crude was observed to be a pseudo-first-order reaction (i.e., in excess of H 2 ), with respect to the polyaromatics and polar maltenic conversion. The following assortment of kinetic parameters was identified under noncatalytic hydrovisbreaking conditions: heterogeneity coefficient, γ ) 1; characteristic temperature, ω ) 29.95 K; and activation energy, E ) 140.9 kJ/mol. Four viscosity mitigation scenarios involving catalytic (FeS, MoS 2 ) and noncatalytic hydrovisbreaking of Doba heavy crude oil were investigated. It was found that the minor proportions of the fractions that distilled before 250 °C and the small asphaltene yields marginally affected the crude viscosity. It was therefore determined that it is possible to meet the viscosity specification for pipeline transportation via (noncatalytic) hydrovisbreaking, which requires neither predistillation (topping) nor post-deasphalting units. The treated crudes and the syncrudes (mixtures of untreated and treated crudes) were observed to exhibit nonelastic viscous Newtonian behavior over the temperature range typical of crude transportation via pipeline. Treated crudes at 440 °C for 25 min and syncrudes that were the result of mixing 50 wt % of untreated crudes with crudes treated at 460 °C for 15 min yielded kinematic viscosities within the pumping specifications (i.e., e 25cSt @ 50 °C). The use of catalysts led to even lessviscous maltenes subfractions; however, post-deasphalting was required, because the catalystcoke mixture, as well as asphaltenes, inflated the viscosity above the norm. An iron sulfide catalyst outperformed a molybdenum sulfide catalyst, in terms of the deasphalted crude viscosity. Aging tests over two-month periods indicated that the higher the treatment severity, the more stable the viscosity of the Doba treated crudes, which is potentially compatible with the residence times of syncrudes within the 1050-km-long transportation pipeline between Chad and Cameroon.

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“…The complex modulus corresponding to the crossover frequency is called the crossover modulus, which is shown in Figure 7. A lower crossover frequency reveals that bitumen has a higher molecular mass, longer relaxation time, and higher softening point, while a lower crossover modulus indicates wider molecular mass distribution and higher polydispersity [35,36]. The crossover modulus and frequencies of different samples are shown in Figure 8.…”

Section: Frequency Sweep Testsmentioning

confidence: 99%

Chemical and Rheological Evaluation of Aged Lignin-Modified Bitumen

et al. 2019

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As bitumen oxidizes, material stiffening and embrittlement occur, and bitumen eventually cracks. The use of anti-oxidants, such as lignin, could be used to delay oxidative aging and to extend the lifetime of asphalt pavements. In this study, the chemical and rheological effect of lignin on bitumen was evaluated by using a single dosage organsolv lignin (10 wt.% dosage). A pressure aging vessel (PAV) was used to simulate the long-term aging process after performing the standard short-term aging procedure, and the lignin-modified bituminous binders were characterized by an environmental scanning electron microscope (ESEM), Fourier-transform infrared (FTIR) spectroscopy, and a dynamic shear rheometer (DSR). From the ESEM results, the uniform microstructure was observed, indicating that the addition of lignin did not affect the worm structure of bitumen. Based on the FTIR test results, lignin-modified bitumen showed that a lower number of carbonyl and sulfoxide compounds were generated after aging than for neat bitumen. Based on the linear amplitude sweep (LAS) results, the addition of lignin slightly reduced the fatigue life of bitumen. From the frequency sweep results, it showed that lignin in bitumen acts as a modifier since the physical interaction between lignin and bitumen predominantly affects the material rheology. Overall, lignin could be a promising anti-oxidant due to its economic and environmental benefits.

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Petroleum Heavy Ends Stability: Evolution of Residues Macrostructure by Aging

Cited by 15 publications

References 43 publications

Ageing of Kukersite Thermobitumen

Ageing of Kukersite Thermobitumen

Lowering the Viscosity of Doba−Chad Heavy Crude Oil for Pipeline TransportationThe Hydrovisbreaking Approach

Chemical and Rheological Evaluation of Aged Lignin-Modified Bitumen

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