Breaking water-in-oil emulsions during the refining of crude oils is an important step before any upgrading process is started. Asphaltene molecules are incriminated as playing an important role in this phenomenon. Unraveling the mechanisms behind the affinity between them and water is a key step to understand how to break these emulsions more easily and require lower amounts of demulsifiers. Choosing which demulsifier molecule(s) to use is also primordial, but to do so rationally, one needs to know which are the molecular interactions in place between asphaltenes, porphyrins and water so that demulsifiers are chosen to destabilize a specific physical–chemical interaction. In this paper, we study the interactions arising between asphaltenes and porphyrins and six different molecules potentially displaying a demulsification action in the presence of water/oil interfaces. We demonstrate that the ionic demulsifier molecules present an interesting potential to either interact strongly with water, replacing asphaltenes in this interaction, or to interact with the active sites of asphaltenes, deactivating them and avoiding any asphaltenic interfacial activity. Finally, we also found that although asphaltenes do not migrate spontaneously toward the water/oil interfaces, porphyrins do so rather easily. This indicates that porphyrins do have an important activity at the water/oil interface.

中文翻译：

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脱盐条件下卟啉和破乳剂在水/油界面沥青质聚集过程中的作用：分子动力学研究

在开始提质之前，在原油精制过程中破坏油包水型乳液是重要的一步。认为沥青质分子在该现象中起重要作用。弄清它们与水之间的亲和力背后的机理是了解如何更轻松地分解这些乳液并需要较少量的破乳剂的关键步骤。选择使用哪种破乳剂分子也很重要，但要合理地做到这一点，就需要知道沥青质，卟啉和水之间的分子相互作用是什么，以便选择破乳剂来破坏特定的物理化学相互作用。在本文中，我们研究了沥青质和卟啉与六个不同分子在水/油界面存在下可能显示破乳作用的相互作用。我们证明，离子破乳剂分子具有与水强烈相互作用，在这种相互作用中取代沥青质或与沥青质的活性位点相互作用，使其失活并避免任何沥青质界面活性的有趣潜力。最后，我们还发现，尽管沥青质不会自发地向水/油界面迁移，但卟啉却相当容易地迁移。这表明卟啉在水/油界面上确实具有重要的活性。在这种相互作用中取代沥青质，或与沥青质的活性位点相互作用，使其失活，并避免任何沥青质界面活性。最后，我们还发现，尽管沥青质不会自发地向水/油界面迁移，但卟啉却相当容易地迁移。这表明卟啉在水/油界面上确实具有重要的活性。在这种相互作用中取代沥青质，或与沥青质的活性位点相互作用，使其失活并避免任何沥青质界面活性。最后，我们还发现，尽管沥青质不会自发地向水/油界面迁移，但卟啉却相当容易地迁移。这表明卟啉在水/油界面上确实具有重要的活性。