Investigating the role of aliphatic olefins in fouling of thermally cracked bitumen by testing fouling tendency of model aliphatic olefin compounds in light fractions

• Published in: Fuel (Guildford) 2024-03, Vol.360, p.130518, Article 130518
• Main Authors: Ali, Mohamed, Xing, Tingyong, Alem, Teclemariam, Chen, Jinwen
• Format: Article
• Language: English
• Subjects: Asphaltenes; Fouling tendency; Olefin compounds; Thermally cracked petroleum products
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.130518

•The role of olefin compounds in fouling was investigated by testing the fouling behaviour of model olefin compounds.•Different olefin types, structures, and boiling points, were blended, individually and in mixtures, with a low-fouling crude to investigate the fouling tendency.•Thermal cracking derived olefin mixture was blende with the heavy fraction of WCS to determine the contribution to fouling.•All model olefin compounds, tested individually or in mixtures, as well as the blended thermal cracking olefin mixture resulted in fouling tendency in the low or low-medium fouling range.•The fouling tendencies of the tested blends were much lower compared to the thermally cracked bitumen. Olefins are considered non-desirable compounds that are formed in the thermal cracking step of crude oil. Due to their high reactivity, they are linked to the fouling tendency of thermally cracked petroleum products. In this work, the role of aliphatic olefins in the fouling of thermally cracked petroleum products is studied by investigating the fouling tendency of model aliphatic olefin compounds blended with Western Canadian Select (WCS) crude, a low-fouling material, in an Alcor hot liquid process simulator (HLPS) fouling testing apparatus. The tested model olefin compounds were selected to have different types (mono-olefin, conjugated diolefins, non-conjugated diolefins), structures, and boiling points. The model olefin compounds were tested individually and in mixtures to determine the fouling tendency. Moreover, a light fraction of thermally cracked bitumen, which contains a significant concentration of olefinic species, was blended with the heavy fraction of WCS to simulate a thermal cracking derived olefin sample with a reasonable olefin content. Olefin and olefin mixture blends were tested in the Alcor HLPS unit to determine the temperature drop (ΔT) due to fouling on the heated rod of the Alcor HLPS unit that leads to a reduction in the heat transfer coefficient. All tested samples resulted in low or low-medium fouling when compared to a thermally cracked bitumen. The results indicated that aliphatic olefins, in the low boiling range, were not the sole contributor to fouling and other constituents, such as asphaltenes or high molecular weight olefins in the heavy fractions, and other properties, such as product stability (measured by P-value), might have a synergetic effect with olefins in the fouling mechanism. Therefore, the role of aliphatic olefins in fouling i