Fouling of processing units because of asphaltene deposition is a common phenomenon that interrupts the operation of oil refineries. In this study, the deposition behavior of a model archipelago asphaltene was investigated in the temperature range of 150 o C to 350 o C. For a fixed surface chemistry, the differences in deposit chemistry with fouling temperature is a function of the thermochemical properties of the model asphaltene. Under static high pressure and high temperature fouling conditions, both surface roughness and chemistry play an important role in asphaltene deposition. Rough surfaces are shown to develop larger deposits because of less restrictive physical barriers to inhibit deposit growth. Passivating the surface with an alumina chemistry significantly reduces the impact of surface roughness, as well as the total amount of deposition. This beneficial effect of using a protective alumina chemistry is attributed to its high thermal stability and low diffusivity that inhibit the uncontrolled formation of thiolate and sulfide deposits that are found on unpassivated steels. Instead, alumina modifies the surface reaction to a self-limiting chemisorption and oxidation process that produces thin sulfate deposits at the surface. With further consideration to the reactive species present in solution, the findings of this study may be extended to determine suitable surface conditions that mitigate asphaltene fouling.
Fouling of oil-exposed surfaces remains a crucial issue due to the continued importance of oil as the world's primary energy source. The key perpetrators in crude oil fouling have been identified as asphaltenes, a poorly-described mixture of diverse polyfunctional molecules that form part of the heaviest fractions of oil.Asphaltenes are responsible for a decrease in oil production and energy efficiency, and an increase in the risk of environmental hazards. Hence, understanding and managing systems that are prone to fouling is of great value but constitutes a 2 Confidential challenge due to their complexity. In an effort to reduce that complexity, a study of a synthesised foulant of archipelago structure is presented. An alternative perspective on previously described solubility and aggregation mechanisms (eg. Critical Nanoaggrerate Concentration, Critical Clustering Concentration) is offered since the characterised system favours a continuous distribution of n-mers instead.A battery of experimental and modelling techniques have been employed to link the bulk and interfacial behaviour of a representative foulant monomer to effective fouling mitigation strategies. This systematic approach defines a new multiscale methodology in the investigation of fouling systems.
A generic approach to the regiospecific synthesis of halogenated polycyclic aromatics is made possible by the one- or two-directional benzannulation reactions of readily available (ortho-allylaryl)trichloroacetates (the “BHQ” reaction). Palladium-catalysed cross-coupling reactions of the so-formed haloaromatics enable the synthesis of functionalised polycyclic aromatic hydrocarbons (PAHs) with surgical precision. Overall, this new methodology enables the facile mining of chemical space in search of new electronic functional materials.
Asphaltene deposition in petroleum refineries is known to be problematic as it reduces efficiency and may lead to structural failure or production downtime. Though several successful approaches have been utilized to limit deposition through the addition of dispersants and inhibitors to petroleum, these methods require constant intervention and are often expensive. In this study, we demonstrate an innovative technique to engineer the surface chemistry of pipeline alloy steels to inhibit asphaltene deposition. Pack aluminization, a standard industrial-scale chemical vapor deposition process, is employed at a low temperature of 600 o C to aluminize API 5L X65 high strength pipe steel substrates. The results showed deposit free steel surfaces after high-pressure and high-temperature fouling experiments. The improvement is attributed to the formation of an aluminide intermetallic phase of Fe 2 Al 5 , which changes the native oxide chemistry to favor alumina over hematite. The continuous passivating oxide scale, acting as a protective barrier,
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