Characterization of Athabasca Vacuum Residue and Its Visbroken Products. Stability and Fast Hydrocarbon Group-Type Distributions

• Published in: Energy & fuels Vol. 21; no. 3; pp. 1631 - 1639
• Main Authors: Carbognani, Lante, Gonzalez, Manuel F, Pereira-Almao, Pedro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2007
• Subjects: Applied sciences; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; Fuels; Processing of crude oil and oils from shales and tar sands. Processes. Equipment. Refinery and treatment units; Asphaltene; Characterization; Thin layer chromatography; Costs; Stability; Hydrocarbon; Thermal cracking; Agglomeration; Mesophase; Condensation; Visbreaking; Vacuum residue
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef0604691

The characterization of thermally cracked residua just before the formation of mesophase and solid phase begins is particularly useful to properly assess changes in properties that heavy molecules might experience close to their massive agglomeration and condensation. This type of study should benefit low-cost thermal cracking technologies such as Visbreaking, which reach their top residual conversion level right at the verge of the solid formation process. This paper covers three topics related to virgin and visbroken Athabasca vacuum residua:  (1) asphaltene intrinsic stabilities, which were determined by titration with a precipitant alkane; (2) relative distributions of hydrocarbon SARA group types (saturates, aromatics, resins, and asphaltenes) that were determined to correlate with product stability, and (3) a fast SARA hydrocarbon (HC) group-type analysis developed in this work for the routine analysis of petroleum virgin and cracked residual products, demonstrated for the study of Athabasca residual fractions. The proposed SARA methodology is described in greater detail. Microdeasphalting was used to determine the content of nC7 asphaltenes. SAR HC group types for maltene phases from deasphalting were analyzed via thin layer chromatography with flame ionization detection (TLC−FID). Microdeasphalting was compared with standard cold and warm routine asphaltene isolation techniques. It was validated by the close match observed with the results from standard procedure IP-143. Published literature on TLC−FID was reviewed, and one optimized methodology was then selected for this study. Careful calibration procedures and validation with preparative group-type analysis confirmed the validity of the proposed TLC−FID fast alternative.