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Book ChapterDOI

Characterization of colloidal stability of blended bitumen

01 Jan 2020-Vol. 45, pp 883-894
TL;DR: In this article, the influence of proportion of PDA pitch and type of crude source on the colloidal stability of bitumen was investigated and it was observed that the compatibility of the material strongly depended on the proportion of the pitch as quantified by the asphalt state of peptization value.
Abstract: Air blowing and propane deasphalting (PDA) blending are the two processes used by the refineries in India to produce paving grade bitumen. In the PDA blending process, the proportion of the constituents (PDA pitch and flux) used in producing bitumen is decided based on the grade of bitumen to be processed. One main issue in the production of bitumen through the blending process is the compatibility of the two constituents used. If the constituents do not exhibit blend stability and compatibility at the microstructural level, it is expected that the binder may not exhibit the required performance even if it meets the appropriate binder specifications such as penetration at 25 \(^{\circ }\)C or viscosity at 60 \(^{\circ }\)C. This study reports one such attempt to check for the compatibility of the blended material using automated flocculation titrimeter. The current investigation primarily focuses on characterizing the influence of proportion of PDA pitch and type of crude source on the colloidal stability of bitumen. The refinery streams processed from a crude oil mixture of Basrah Light (66%) and Murban (34%) was identified as the first crude source and a crude oil mixture of AXL (80%), Basrah (10%) and Iran Mix (10%) was identified as the second crude source. Two different blend proportions of PDA pitch and flux from both the crude sources were made, and these were 75:25 and 80:20. These blend proportions were manufactured in a high shear rate blending facility. All the blends and the components were subjected to titrimetry at the unaged condition. It was seen that the compatibility of the material strongly depended on the proportion of the pitch as quantified by the asphalt state of peptization (P) value. The rheological properties of the blends were quantified by performance grading and frequency sweep tests. It was observed that blend samples with better compatibility also exhibited excellent rheological properties.
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Journal ArticleDOI
TL;DR: A number of different models that have been applied to modeling of asphaltene precipitation and estimating asphalte solubility in various systems are critically reviewed in this article, with particular attention paid to the basic assumptions and the performance of the models as compared to the present knowledge of composition and phase equilibrium of Asphaltenes.

218 citations

Journal ArticleDOI
TL;DR: In this article, the bitumens of 70 and 50 pen were analyzed for generic composition, macrostructure and colloidal stability, and the size of asphaltene micelles and the extent of their aggregation were influenced by the chemical type of the feedstock and the method of bitumen production.

49 citations

Journal ArticleDOI
TL;DR: In this paper, 26 bitumens covering a large variety in crude origin and processing conditions were evaluated, using rheological tests methods and the recently developed bitumen solubility model (BISOM) titrations.
Abstract: In this study, 26 bitumens covering a large variety in crude origin and processing conditions were evaluated, using rheological tests methods and the recently developed bitumen solubility model (BISOM) titrations. In BISOM, bitumen is characterised by its solubility in three different solvents, relating respectively to Van der Waals, polar and hydrogen bonding interactions. Since both BISOM and rheology produce a large number of data, and since it is not possible to change one parameter at a time, to investigate its influence, a statistical program SIMCA was used. In conclusion, it was found that stiffness versus temperature is, for unmodified bitumen, completely determined by the conventional test methods (penetration, R&B, viscosity) as was already stated by Heukelom. However, the shape of the phase angle with temperature or the elastic behaviour at a given stiffness shows a good relation with the parameters determining the hydrogen bonding potential and the polar interactions. The more hydroge...

18 citations