Asphaltenes, resins, and other petroleum macromolecules

Wiehe, Irwin A.; Liang, K. S.

doi:10.1016/0378-3812(95)02954-0

Cited by 227 publications

(175 citation statements)

References 15 publications

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“…Taking a lead from the pendant-core model, Figure 14 has been hypothesized, which elucidates the eventual formation of graphite-like structure, formed by the clustering of aromatic free radicals and distillate formation by the cracking of the aliphatic linkages that hold the aromatic structures together. Wiehe and Liang (1996) reported a microemulsion model for petroleum. Figure 15 shows a possible simplifi ed form of the microemulsion model reported by Wiehe and Liang (1996).…”

Section: Reaction Mechanism and Kineticsmentioning

confidence: 99%

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Petroleum Residue Upgrading Via Delayed Coking: A Review

et al. 2007

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getting burdened with heavy residues that are subsequently obtained by processing heavy crudes. Heavy crudes (≤ 20 ºAPI) yield large amount of residual fractions such as atmospheric residue (AR, initial boiling point, IBP > 343ºC) and vacuum residue (VR, IBP > 500ºC) as shown in Figure 1 (Boduszynski, 2002). The processes that convert these heavy ends into lighter, more value-added products are termed as bottom-of-the-barrel conversion processes or residue upgrading processes.Among the various processes available, the delayed coking process is a long-time workhorse as regards the bottom-of-thebarrel upgrading (Schulman et al., 1993). World coking capacity has reached about 210 MMTPA (Swaty, 2005), comprising India's World petroleum residue processing capacity has reached about 725 million metric tons per annum (MMTPA). The high demand for transportation fuels and the ever-rising heavy nature of crude oil have resulted in a renewed interest in the bottom-of-the-barrel processing using various conversion processes. Delayed coking, known for processing virtually any refi nery stream (which not only poses a serious threat to environment, but also involves a disposal cost) has garnered tremendous importance in the current refi ning scenario. Needle coke obtained from delayed coking process is a highly sought-after product, which is used in electric arc furnaces (in the form of graphite electrodes) in steel making applications. In the present communication, the published literature has been extensively analyzed and a state-of-the-art review has been written that includes: (1) importance and place of delayed coking as a residue upgrading process in the current refi ning scenario; (2) coking mechanism and kinetics; (3) design aspects; (4) feedstocks suitable for the production of needle coke; (5) characteristics of needle coke; (6) factors affecting needle coke quality and quantity; and (7) future market for needle coke. An attempt has been made to get the above-mentioned aspects together in a coherent theme so that the information is available at a glance and could be of signifi cant use for researchers and practising refi ners.La capacité de traitement des résidus pétroliers mondiaux a atteint environ 725 millions de tonnes métriques par année (MMTPA). La forte demande de carburants pour le transport et la nature de plus en plus lourde de l'huile brute ont renouvelé l'intérêt pour le traitement des résidus (fond de baril) à l'aide de divers procédés de conversion. La cokéfaction retardée, connue pour traiter virtuellement tout courant de raffi nage, qui non seulement constitue une menace sérieuse pour l'environnement, mais également implique des coûts d'élimination, a pris une importance considérable dans le scénario de raffi nage actuel. Le coke en aiguilles obtenu à partir du procédé de cokéfaction retardée est un produit très recherché, qui est employé dans les fours à arc électriques (sous la forme d'électrodes de graphite) dans les applications de fabrication de l'acier. Dans le présent article, on a analysé de m...

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Section: Reaction Mechanism and Kineticsmentioning

confidence: 99%

“…Wiehe and Liang (1996) reported a microemulsion model for petroleum. Figure 15 shows a possible simplifi ed form of the microemulsion model reported by Wiehe and Liang (1996). According to this model, asphaltenes are dispersed by the surfactant-like property of resins that in turn are held in solution by aromatics.…”

Section: Reaction Mechanism and Kineticsmentioning

confidence: 99%

Petroleum Residue Upgrading Via Delayed Coking: A Review

et al. 2007

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“…This definition reveals little about asphaltenes except that they are the least soluble fraction in petroleum. It has been suggested that over 100,000 structures make up the entire set of molecules in the asphaltene fraction of one crude oil 9 . In fact, no one has positively identified the chemical structure of even one asphaltene molecule.…”

Section: The Main Fractions Of Petroleummentioning

confidence: 99%

Changes in Asphaltene Microenvironments Evidenced by Fluorescence Solvatochromism

Pietraru

Cramb

2003

Langmuir

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This work involved the study of Cold Lake asphaltenes' behavior in toluene and o-dichlorobenzene. The changes in asphaltene microenvironments with the increase in asphaltene concentration were observed using fluorescence solvatochromism. The reporter molecule chosen was the environmentally sensitive fluorophore PRODAN. This procedure represents a novel and sensitive method to study asphaltene solutions, and might bring additional information to the existent database of asphaltene properties.A pre-aggregation model was developed to explain the experimental observations, and a definition for the critical aggregation concentration was proposed. The model is valid for low asphaltene concentrations and is supported by direct measurements of refractive indices for asphaltene solutions. Atomic force microscopy was used to image asphaltene entities. The size distribution indicated that asphaltene particles do not change significantly with the increase in concentration. The appearance of larger aggregates in solutions with concentrations above CAC might support the validity of the model.

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“…The resin constituents play an important role in the stability of petroleum and prevent separation of the asphaltene constituents as a separate phase (Swanson, 1942;Koots and Speight, 1975;Buckley, 1997;Wiehe and Liang, 1996;Li et al, 1997Li et al, , 1999Premuzic and Lin, 1999).…”

Section: Resin Constituentsmentioning

confidence: 99%

Petroleum Asphaltenes - Part 1: Asphaltenes, Resins and the Structure of Petroleum

Speight¹

2004

Oil & Gas Science and Technology - Rev. IFP

401

293

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Résumé -Les asphaltènes, composés pétroliers. Partie 1 : Asphaltènes, résines et structure du pétrole -La définition précise des composés non volatils d'un pétrole (asphaltènes, résines, autres constituants plus spécifiques aux résidus et aux charges lourdes) constitue une donnée nécessaire aux opérateurs. Il est difficile de distinguer des espèces suivant de simples caractéristiques chimiques ou structurelles. Ceci est particulièrement valable pour les asphaltènes et les résines dont la procédure de séparation détermine non seulement le rendement mais aussi la qualité de la fraction. Par exemple, l'emploi de différents solvants influence considérablement le rendement. La technique appliquée entraîne ou non la présence de résines coprécipitées avec les asphaltènes. Ceci provient de la définition générale des asphaltènes et des résines, respectivement comme composés insolubles et solubles dans le n-pentane (ou le n-heptane). Les résultats de récentes études de structure contredisent les anciennes descriptions d'asphaltènes en tant que composés contenant de larges plages de noyaux aromatiques polycondensés et montrent qu'une grande diversité de fonctions chimiques jouent aussi un rôle dans le comportement des asphaltènes. Ainsi, la stabilité d'un pétrole peut-elle être représentée par un système de trois phases : les asphaltènes, la fraction aromatique (incluant les résines) et la fraction saturée, le tout se trouvant en équi-libre suivant une délicate harmonie. Plusieurs facteurs, tels que l'oxydation, peuvent altérer ce système, conduisant à une instabilité ou une incompatibilité des espèces due à la modification de leur polarité et de leurs liaisons. Abstract

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Asphaltenes, resins, and other petroleum macromolecules

Cited by 227 publications

References 15 publications

Petroleum Residue Upgrading Via Delayed Coking: A Review

Petroleum Residue Upgrading Via Delayed Coking: A Review

Changes in Asphaltene Microenvironments Evidenced by Fluorescence Solvatochromism

Petroleum Asphaltenes - Part 1: Asphaltenes, Resins and the Structure of Petroleum

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