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Journal Article

A phase separation kinetic model for coke formation

01 Jan 1993-Preprints-American Chemical Society Division of Petroleum Chemistry (American Chemical Society)-Vol. 38, Iss: 2, pp 428-433
TL;DR: In this article, it was shown that the previously unreacted asphaltene was the fraction with the highest rate of thermal reaction but with the least extend of reaction, leading to the preferential conversion of the most associated asphatene to coke.
Abstract: Coke formation during the thermolysis of petroleum residua is postulated to occur by a mechanism that involve the liquid-liquid phase separation of reacted asphaltene to form a phase that is been in abstractable hydrogen. This mechanism provide the basis of a model that quantitatively describe the kinetics for the thermolysis of ColD Lake vacuum residuum and its deasphalted oil in a open fuse reactor at 400°C. The previously unreacted asphaltene were found to be the fraction with the highest rate of thermal reaction but with the least extend of reaction. Further evidence of the liquid-liquid phase separation was the observation of spherical particle of liquid crystalline coke and the preferential conversion of the most associated asphatene to coke
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors present an extended kinetic model for high-level reaction classes, such as gas phase and liquid phase pyrolysis, polymer thermal degradation, oxidative coupling and several other chemical processes.

420 citations

Journal ArticleDOI
I.A. Wiehe1, K.S. Liang1

215 citations

Journal ArticleDOI
TL;DR: In this article, the authors derived the oil compatibility model from two hypotheses: one hypothesis is that asphaltenes precipitate from the oil at the same mixture solubility parameter, no matter that the oil is blended with non-complexing liquids or another oil.
Abstract: Although incompatible crude oils have not been previously discussed in the scientific literature, they are discovered to be relatively common. Consequently, with the need of a predictive method, the Oil Compatibility Model was derived from two hypotheses. One hypothesis is that asphaltenes precipitate from the oil at the same mixture solubility parameter, no matter that the oil is blended with noncomplexing liquids or another oil. The other hypothesis is that the solubility parameter of a mixture is the volumetric average solubility parameter. As a result, the solubility parameter of a crude oil and its flocculation solubility parameter on a toluene−n-heptane scale can be determined based upon mixing the crude oil with toluene and n-heptane and determining if each mixture dissolves or precipitates asphaltenes. Thereafter, the correct proportions and correct order of blending oils to ensure compatibility can be specified. A refinery example is given where determining the correct order of blending potential...

211 citations

Journal ArticleDOI
Abstract: In petroleum science, the term resin generally implies material that has been eluted from various solid adsorbents, whereas the term maltenes (or petrolenes) indicates a mixture of the resins and oils obtained as filtrates from the asphaltene precipitation. Thus, after the asphaltenes are precipitated, adsorbents are added to the n-pentane solutions of the resins and oils, by which process the resins are adsorbed and subsequently recovered by the use of a more polar solvent, and the oils remain in solution. The resin fraction plays an important role in the stability of petroleum and prevents separation of the asphaltene constituents as a separate phase. Indeed, the absence of the resin fraction (produced by a variety of methods) from the maltenes influences the ability of the de-resined maltenes to accommodate the asphaltenes either in solution or as a stable part of a colloidal system. In spite of the fact that the resin fraction is extremely important to the stability of petroleum, there is surprisingly...

189 citations

Journal ArticleDOI
TL;DR: In this article, the authors explored the chemical and physical processes that cause fouling in organic mixtures under non-oxidative conditions, including autoxidation, polymerization and thermal decomposition.

155 citations

References
More filters
Journal ArticleDOI
TL;DR: In this article, the authors present an extended kinetic model for high-level reaction classes, such as gas phase and liquid phase pyrolysis, polymer thermal degradation, oxidative coupling and several other chemical processes.

420 citations

Journal ArticleDOI
I.A. Wiehe1, K.S. Liang1

215 citations

Journal ArticleDOI
TL;DR: In this article, the authors derived the oil compatibility model from two hypotheses: one hypothesis is that asphaltenes precipitate from the oil at the same mixture solubility parameter, no matter that the oil is blended with non-complexing liquids or another oil.
Abstract: Although incompatible crude oils have not been previously discussed in the scientific literature, they are discovered to be relatively common. Consequently, with the need of a predictive method, the Oil Compatibility Model was derived from two hypotheses. One hypothesis is that asphaltenes precipitate from the oil at the same mixture solubility parameter, no matter that the oil is blended with noncomplexing liquids or another oil. The other hypothesis is that the solubility parameter of a mixture is the volumetric average solubility parameter. As a result, the solubility parameter of a crude oil and its flocculation solubility parameter on a toluene−n-heptane scale can be determined based upon mixing the crude oil with toluene and n-heptane and determining if each mixture dissolves or precipitates asphaltenes. Thereafter, the correct proportions and correct order of blending oils to ensure compatibility can be specified. A refinery example is given where determining the correct order of blending potential...

211 citations

Journal ArticleDOI
Abstract: In petroleum science, the term resin generally implies material that has been eluted from various solid adsorbents, whereas the term maltenes (or petrolenes) indicates a mixture of the resins and oils obtained as filtrates from the asphaltene precipitation. Thus, after the asphaltenes are precipitated, adsorbents are added to the n-pentane solutions of the resins and oils, by which process the resins are adsorbed and subsequently recovered by the use of a more polar solvent, and the oils remain in solution. The resin fraction plays an important role in the stability of petroleum and prevents separation of the asphaltene constituents as a separate phase. Indeed, the absence of the resin fraction (produced by a variety of methods) from the maltenes influences the ability of the de-resined maltenes to accommodate the asphaltenes either in solution or as a stable part of a colloidal system. In spite of the fact that the resin fraction is extremely important to the stability of petroleum, there is surprisingly...

189 citations

Journal ArticleDOI
TL;DR: In this article, the authors explored the chemical and physical processes that cause fouling in organic mixtures under non-oxidative conditions, including autoxidation, polymerization and thermal decomposition.

155 citations