Resolution of water in crude oil emulsion by some novel aromatic amine polyesters

A review study on new aspects of biodemulsifiers: Production, features and their application in wastewater treatment

The effluent produced in refineries is in the form of an oil/water emulsion that must be treated. These emulsions are often stable and a suitable method must be used to separate the oil from the emulsion. Recently, biosurfactants or biodemulsifiers have received much attention to reduce the interfacial tension between two liquids. Biodemulsifiers are produced by microorganisms and have several benefits over chemical demulsifiers such as low-toxic, biodegradability, eco-friendly and easy synthesis. They can eliminate two phases by changing the interfacial forces between the water and oil molecules. Biosurfactants are categorized based on the molecular weight of their compounds (low or high molecular weight). Sophorolipids, lipopeptides rhamnolipids, trehalolipids, glycolipid, lipoproteins, lichenysin, surfactin, and polymeric biosurfactants are several types of biosurfactants, which are produced by bacteria or fungi. This review study provides a deep evaluation of biosurfactants in the demulsification process. To this end, different types of biosurfactants, the synthesis method of various biosurfactants using various microorganisms, features of biosurfactants, and the role of biodemulsifiers in the demulsification process are thoroughly discussed. Also, the impact of various efficient factors like pH, microorganism type, temperature, the oil content in the emulsion, and gravity on biodemulsificaion was studied. Finally, the mechanism of the demulsification process was discussed. According to previous studies, rhamnolipid biodemulsifier showed the highest biodemulsification efficiency (100%) in the removal of oil from an emulsion.

An Overview of Recent Advances in State-of-the-Art Techniques in the Demulsification of Crude Oil Emulsions

The processing of crude oil often requires the extraction of a large amount of water. Frequently, crude oil is mixed with water to form water-in-crude oil emulsions as the result of factors such as high shear at the production wellhead and surface-active substances that are naturally present in crude oil. These emulsions are undesirable and require demulsification to remove the dispersed water and associated inorganic salts in order to meet production and transportation specifications. Additionally, the demulsification of these crude oil emulsions mitigates corrosion and catalyst poisoning and invariably maximizes the overall profitability of crude oil production. Recently, there has been growing research interest in developing workable solutions to the difficulties associated with transporting and refining crude oil emulsions and the restrictions on produced water discharge. Therefore, this paper reviews the recent research efforts on state-of-the-art demulsification techniques. First, an overview of crude oil emulsion types, formation, and stability is presented. Then, the parameters and mechanisms of emulsification formation and different demulsification techniques are extensively examined. It is worth noting that the efficiency of each of these techniques is dependent on the operating parameters and their interplay. Moreover, a more effective demulsification process could be attained by leveraging synergistic effects by combining one or more of these techniques. Finally, this literature review then culminates with propositions for future research. Therefore, the findings of this study can help for a better understanding of the formation and mechanisms of the various demulsification methods of crude oil to work on the development of green demulsifiers by different sources.

Mechanisms, performance optimization and new developments in demulsification processes for oil and gas applications

The present review discusses new developments and optimization of demulsification processes in oil and gas applications, and highlights the critical parameters. Discussed are the primary mechanisms of demulsification, as well as the strategies for developing optimum demulsifiers. Demulsification mechanisms are presented in the context of emulsion stability principles which are equally applicable to the destabilization of crude oil-water emulsions. The present paper is a concise overview of the various surfactant classes and their structure-activity relationship. It correlates demulsification optimization with surfactant properties and their applications. These classes include, but are not limited to pluronic block co-polymers, as well as amine- and siloxane based nonionic surfactants. The emphasis is on providing some strategies for achieving optimum crude oil-water separation efficiency by tuning the demulsifier to the intended application and crude oil properties. A brief overview of unconventional analytical techniques, which reach beyond the standard demulsifier evaluation methods, i.e., Near Infrared Spectroscopy (NIR), and in particular, low resolution NMR relaxometry, highlights their role in monitoring demulsification processes.

Selective hydrogenation of nitroarenes using an electrogenerated polyoxometalate redox mediator

The 2-electron reduced form of the polyoxometalate silicotungstic acid (H₄[SiW₁₂O₄]) is shown to be an effective and selective hydrogenation agent for a range of nitroarenes without the need for any co-catalyst.