Browsing by Author "Ashtari, Maryam"

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    New Pathways for Asphaltenes Upgrading via Oxy-cracking in Liquid Phase
    (2016) Ashtari, Maryam; Pereira Almao; De Visscher, Alex; Moore, Robert Gordon
    Surplus asphaltenes production in northern Alberta facilities, led to searching new pathways to process asphaltenes pitches as the most challenging material in heavy oils. Due to the additional expenses these compounds could cause as a result of precipitation at flow lines, well bore and production separators, the separation of them from heavy oil and potentially extracting valuable products from them is relevant. Oxy cracking asphaltenes in liquid phase under alkali conditions could be a new approach to creating more value from asphaltenes, this is the topic of this research. Asphaltene drops were oxy-solubilized in water with the ultimate intention of reducing their molecular weight, converting them to analogs of humic substances, which could have extensive applications as co-fertilizers for enhancing soil quality and productivity in agriculture and many other industrial new applications as photo-sensibilizers for solar cell panels. The intention is to convert these organic materials via a low energy requiring mechanism into intermediate simpler oxidized-organic compounds minimizing secondary end products like carbon oxides. For this purpose, the optimum operating conditions, reaction kinetics and depiction of reaction mechanism were researched for C5 precipitated asphaltenes during oxy-cracking in batch mode. A model based on sequential-parallel reactions from the asphaltenes to water-soluble products and CO2 was found to describe the process adequately. The results showed that by introducing oxygen onto asphaltenes at moderate temperatures (180 °C-225 °C) and pressures (300-500 psi) in liquid phase, asphaltenes oxy-cracked to humic and fulvic analogs and under more severe reaction conditions, most of the humic analogs converted to fulvic analogs having lower molecular weight in comparison with humic analogs. Afterward, a continuous bench scale set up was conceptualized, built and tested based on batch experiments to evaluate the continuous oxy-cracking of asphaltenes in water. Comprehensive characterization analysis was carried out on asphaltenes oxy-cracking products in batch and continuous mode to understand the chemical structure of products. Production of oxidized functionalities like carboxylic acids, their salts, methyl ethers and esters, sulfur-oxidized forms plus phenolics, were determined as the most significant fractions soluble in water. Upstream solubilization and industrialization of derivatives of asphaltenes in water before the crude oils are mobilized throughout the commercialization chain could also decrease challenges regarding facilities and pipelines plugging.