The effect of cationic surfactants on bitumen's viscosity and asphaltene nanostructure under thermal partial upgrading

Abstract

Bitumen extracted from oil sands is a highly viscous fluid; thus, its transportation via pipelines in its original form resembles a major challenge. Partial upgrading is a recently proposed approach that aims to reduce bitumen's viscosity to meet the pipeline specifications. To optimize the process and make it more cost-effective, a novel approach is proposed and researched in this study. Ionic surfactants were for the first time employed to promote thermal cracking reactions and dispersion of asphaltenes in bitumen at elevated upgrading temperatures. Three surfactants representing the cationic, nonionic, and anionic charges were studied at the thermal upgrading conditions (360-400 • C) at their optimal addition ratios to mimic the bitumen partial upgrading conditions. The results demonstrated that the cationic surfactant (dodecyltrimethylammonium bromide, DTAB) surpassed the other two surfactants and that with the addition of only 0.25 wt% of it, it can effectively reduce the viscosity of bitumen by up to 60% more than the upgraded bitumen with no additives under the same upgrading temperature.The Saturates, Aromatics, Resins, and Asphaltene analysis revealed that the contents of saturates and aromatics within the upgraded bitumen were also enhanced when DTAB was added. Moreover, the detailed asphaltene nanostructural analysis using X-ray diffraction, high-resolution transmission electron microscope, and thermogravimetric analysis revealed that the addition of the cationic surfactant (DTAB) resulted in an increased asphaltene nanostructural disorder, smaller polycyclic aromatic hydrocarbons size, and increased fringe curvature, as compared with the upgraded bitumen's asphaltene with no surfactants. Hence, the results have suggested that DTAB, a cheap and readily available ionic surfactant, can serve as a potential upgrading additive for designing partial upgrading procedures to produce upgraded bitumen with much less viscosity at lower upgrading temperatures.

Asphaltene Precipitation/Deposition Estimation and Inhibition through Nanotechnology: A Comprehensive Review

“…The special surface properties of these coatings enable easier dislodging or dissolution of the asphaltenes, minimizing the need for extensive mechanical or chemical cleaning procedures. Additionally, these coatings are designed to be durable and stable under the harsh conditions of oil production, withstanding corrosive fluids, high pressures, and elevated temperatures commonly encountered in production systems [228][229][230][231][232].…”

Harnessing the Power of Microwave Irradiation: A Novel Approach to Bitumen Partial Upgrading

“…As a result, some partial upgrading techniques that involve a combination of heating, diluent mixing, and upgrading to reduce viscosity by cracking macromolecules are alternatively being used [7]. Nonetheless, substantial viscosity reduction is typically achieved at relatively high temperatures of 400 • C + in processes such as visbreaking and/or coking [8], making traditional thermal upgrading techniques both energy-intensive and time-consuming [9] and ultimately leading to substantial GHG emissions. As such, the exploration of new innovative, green, and sustainable partial upgrading techniques is required.…”

“…Molecules 2023, 28, x FOR PEER REVIEW 2 of 19 traditional thermal upgrading techniques both energy-intensive and time-consuming [9] and ultimately leading to substantial GHG emissions. As such, the exploration of new innovative, green, and sustainable partial upgrading techniques is required.…”