A solvent-resid phase diagram for tracking resid conversion

Wiehe, Irwin A.

doi:10.1021/ie00002a013

Cited by 137 publications

(133 citation statements)

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“…The choice of the column operating temperature of 80 °C in the present work would tend to minimise effects due to the adsorption (and shift to longer times) of non-polar species. 30 These authors 29 also attempted to characterise the material eluting at the exclusion limit of the column by heatedprobe mass spectrometry. The latter technique showed little ion abundance above masses of about 250 u; the reported upper limit of the scan was 500 u.…”

Section: Polarity Vs Molecular Mass In Secmentioning

confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Herod

Lázaro

Rahman

et al. 1997

Rapid Commun. Mass Spectrom.

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This paper describes experiments carried out within the framework of examining capabilities of MALDI-TOF-MS in the characterisation of fossil fuels and related materials. The work has focused on the effect of interactions between sample structure and matrix composition on the quality of MALDI spectra. Solvent extracts from six kerogens have been examined by MALDI-MS in the presence of three matrices of different composition and in the absence of matrix (laser ablation). The kerogen extracts have also been characterised by size exclusion chromatography (SEC) and UV-fluorescence spectroscopy (UV-F). In the presence of the three matrices (sinapinic acid, 2,5-dihydroxybenzoic acid and α-cyano-3-hydroxycinnamic acid), spectra of extracts from the three geologically 'younger' kerogens showed larger molecular mass distributions compared to spectra of extracts from the corresponding 'older' kerogens. This result directly contradicted trends observed in the absence of matrix, where extracts from 'older' kerogens showed larger molecular mass distributions. Results from SEC and UV-F agreed with trends observed in MALDI-spectra acquired in the presence of matrix, particularly sinapinic acid. By contrast, we recently reported that high mass signal in laser ablation mass spectra of the pyridine-insoluble fraction of a coal tar pitch, obtained in the absence of matrix, closely matched signals obtained in the presence of sinapinic acid. Compared to the highly condensed aromatic structure of the coal tar pitch, the kerogen extracts (of considerably higher oxygen content) appear less able to readily absorb incident laser radiation (337 nm) in the absence of externally added matrix. The argument is consistent with apparently more efficient absorption of incident laser radiation by the geologically 'older' samples, when no matrix was used. Structural characteristics suggest that the geologically 'older' samples would be better able to act as 'self-matrix'. Thus, differences in structure and composition of the samples appear to go some way towards explaining differences between trends observed in the presence/absence of matrix. Dependence of MALDI spectra on molecular structure has also been found for two sets of biomass derived samples. Considerably more work appears warranted to determine MALDI-MS parameters appropriate to the analysis of the more oxygenated, lower rank, samples. Recently, 1,2 we described changes in the MALDI-TOF mass spectra of coal derived liquids as a function of changes in (i) ion extraction voltage, (ii) laser power (iii) matrix composition and (iv) sample deposition density. Increasing ion extraction voltages helps provide a more complete inventory of species already ionised, without otherwise disturbing the sample. It would appear advantageous, therefore, to use the highest possible values of the extraction voltage, apparently irrespective of other experimental parameters. Clearly, the upper limit of the ion extraction voltage is determined by the capabilities of installed hardware. We have, to date, been a...

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Section: Polarity Vs Molecular Mass In Secmentioning

confidence: 99%

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Herod

Lázaro

Rahman

et al. 1997

Rapid Commun. Mass Spectrom.

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“…As conversion proceeds therefore, the residues processed become less stable, sometimes precipitating to such a point that they block up the pipes and the exchangers. Studies conducted on asphaltenes to investigate the conversion mechanisms have been described in several publications: Merdrignac et al (2004), Bartholdy and Andersen (2000), Wiehe (1992 and1993). Many questions are still unanswered, however, since prediction of flocculation phenomena remains a challenge: -what is the maximum conversion rate possible for a given crude without destabilising the effluents?…”

Section: Introduction -Reminder Of the Stakesmentioning

confidence: 99%

Characterisation of Asphaltenes and Modelling of Flocculation – State of the Art

Pina¹,

Mougin²,

Béhar³

2006

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Caractérisation des asphaltènes et modélisation de la floculation -État de l'Art -Ce travail présente un état de l'art concernant la floculation des asphaltènes avec deux grands items : la caractérisation des asphaltènes dans différents milieux et la modélisation de la floculation. Cette revue commence par une caractérisation des asphaltènes proprement dite puis des caractérisations de ces derniers dans des solvants synthétiques ou des bruts. Nous insistons sur les techniques de détermination de masses molaires et de diffraction. L'incidence d'un ajout de bon/mauvais solvant est également discutée. La seconde partie de cette revue concerne la modélisation de la floculation. Elle examine les différents modèles de la littérature avant de présenter celui de Szewczyk et Béhar (1999) et son intégration dans un simulateur de réservoir. Les modèles disponibles requièrent encore des données expérimentales délicates à acquérir et un effort de recherche doit être réalisé pour améliorer cet état de fait. Abstract -Characterisation of Asphaltenes and Modelling of Flocculation -State of the Art -This document describes a state of the art concerning the flocculation of asphaltenes with two major sections: characterisation of asphaltenes in various environments and modelling of flocculation. This review starts with the characterisation of asphaltenes as such, then their characterisation in synthetic solvents or crudes. Emphasis is placed on molar mass determination and diffraction techniques. The impact of adding a good/poor solvent is also discussed. The second part of this review is dedicated to modelling.We first examine the various models in the literature before describing the Szewczyk and Béhar (1999) model and its integration in a reservoir simulator. The models available still require experimental data which is difficult to collect and further research is needed to improve this situation.Petroleum Industry Applications of Thermodynamics Applications de la thermodynamique dans l'industrie pétrolière

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“…Even molecules with limited solubility and low H:C ratio, such as asphaltenes, may go through chemical changes without completely becoming a different solubility class, such as coke. The solvent-resid phase diagram presented by Wiehe [25] shows that one possible path during conversion of asphaltenes involves changes in their hydrogen content or Fig. 4 Infrared spectra of raw asphaltenes and total oxidized product after wet air oxidation at 52°C for 2, 4 and 8 h, respectively Table 5 Relative peak intensities of absorptions at different regions of the IR spectra for the total oxidized products after oxidation using moist air at 52°C 5 Asphaltene content of the products obtained by heating asphaltenes for 2 h at 52 and 100°C, under air and moist air atmosphere molecular weight without affecting their nature as asphaltenes.…”

Section: Discussionmentioning

confidence: 99%

Low-temperature oxidative asphaltenes liquefaction for petrochemicals: fact or fiction?

Sánchez

Klerk

2016

Appl Petrochem Res

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Asphaltene is the heavy and heteroatom-rich fraction of petroleum that is rejected during a solvent deasphalting process. In patent literature there are claims that state that this material can be converted into an aromatic petrochemical feedstock by oxidative liquefaction at low temperature. To evaluate the validity of these claims, asphaltenes from an industrial solvent deasphalting process were oxidized with dry and water-saturated air at temperatures in the range 45-100°C. Infrared spectroscopy of the oxidized product confirmed that oxygen was incorporated as C=O and C-O. Under all experimental conditions studied little oxidative degradation was observed that would lead to the production of a petrochemical feedstock. Nevertheless, some observations of scientific value were made about the low-temperature conversion of asphaltenes. During autoxidation with dry air, the n-pentane-insoluble fraction increased. On the contrary, when oxidation was conducted with water-saturated air, the formation of additional n-pentane-insoluble material was suppressed. Mild heating of asphaltenes under nitrogen atmosphere also caused the n-pentane-insoluble content to increase. Spectroscopic evidence showed that esters are formed during oxidation at *100°C. The temperature dependence of this reaction was explained and a possible reaction pathway for cycloalkane to ester conversion was presented. Ester selectivity was determined by the competition between hydrogen abstraction and b-scission of the alkoxy radical.

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A solvent-resid phase diagram for tracking resid conversion

Cited by 137 publications

References 16 publications

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of kerogen extracts: effect of interactions between sample structure and matrix

Characterisation of Asphaltenes and Modelling of Flocculation – State of the Art

Low-temperature oxidative asphaltenes liquefaction for petrochemicals: fact or fiction?

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