Novel Star Polymeric Nonionic Surfactants as Crude Oil Emulsion Breakers

A Review of Oil-Solid Separation and Oil-Water Separation in Unconventional Heavy Oil Production Process

Unconventional heavy oil ores (UHO) have been considered an important part of petroleum resources and an alternative source of chemicals and energy supply. Due to the participation of water and extractants, oil-solid separation (OSS) and oil-water separation (OWS) processes are inevitable in the industrial separation processes of UHO. Therefore, this critical review systematically reviews the basic theories of OSS and OWS, including solid wettability, contact angle, oil-solid interactions, structural characteristics of natural surfactants and interface characteristics of interfacially active asphaltene film. With the basic theories in mind, the corresponding OSS and OWS mechanisms are discussed. Finally, the present challenges and future research considerations are touched on to provide insights and theoretical fundamentals for OSS and OWS. Additionally, this critical review might even be useful for the provision of a framework of research prospects to guide future research directions in laboratories and industries that focus on the OSS and OWS processes in this important heavy oil production field.

The Influence of Newly Synthesized Demulsifiers on the Interfacial Rheological Properties of a Naturally Occurring Water/Oil Emulsion

This research aimed to synthesize new polymeric nonionic demulsifiers (DA, DB, and DC) to break 50% of naturally occurring water/oil emulsions. The prepared demulsifiers were synthesized in only two stages utilizing simple techniques. ¹H and ¹³CNMR, MS, and FTIR spectroscopies were performed to validate the chemical composition of the synthesized demulsifiers. The relative solubility number (RSN) and partition coefficient (K _p) were determined for the three demulsifiers. The interfacial tension (IFT) and dehydration ratios of DA, DB, DC, and their triblock copolymers were investigated. Also, interfacial rheological properties for the three demulsifiers were measured. The findings demonstrate that DB possesses a higher RSN value than DA and DC owing to its hydrophilicity. DC exhibited the lowest IFT value compared to DA, DB, and their corresponding triblock copolymers. DB and DC are more effective in demulsifying than DA and triblock copolymers. DC achieved a 100% dehydration ratio at a low dosage of 75 ppm after 120 min. DC's remarkable performance can be attributed to its aromatic core, molecular weight, and high interfacial activity. According to the rheological data, a higher dehydrating ratio is attained when the demulsifier has a great capacity to lower the viscoelasticity of the W/O emulsion interface. The maximum decrease in G' and G″ values was attained by DC. The mechanism of DC's demulsifying interaction on a naturally occurring W/O emulsion was elucidated.

A critical review of the development and demulsification processes applied for oil recovery from oil in water emulsions

The formation of stable emulsions is a fundamental problem in oil industry that can result in a sequence of environmental and operational problems. Chemical demulsification is extensively applied for the recovery of oil from water as well as water from oil. This review introduces different chemical demulsifiers applied for the demulsification and recovery of oil from oil in water (O/W) emulsions. Main types of surfactants (anionic, cationic, nonionics and amphoteric) involved in the formation of emulsions and enhances their stability were discussed. Promising demulsifiers such as nanoparticle (NP), hyperbranched polymers, and ionic liquids (IL), which achieved high oil recovery rate, parameters influencing demulsification efficiency and demulsification mechanisms were explored. Lastly, improvements, challenges, and new changes being made to chemical demulsifiers were underlined. Functionalized magnetic nanoparticles and hyperbranched polymers were very effective in recovering oil from O/W emulsions with an efficiency >95%. Polymers with highly hydrophilic content and high molecular weight can achieve excellent oil recovery rates due to higher interfacial activity, higher dispersion, and presence of specific functional groups. Although ionic liquids could achieve oil recovery up to 90%, high cost limits their applications. NPs showed excellent oil recovery behavior at low concentrations and ambient temperature. Demulsification efficiency of NPs can be enhanced by functionalize with other components (e.g., polymers and surfactants), while service life can be extend by silica coating. Future challenges include scaling up the use of NPs in oil recovery process and highlighting contrasts between lab-scale and field-scale applications.

Effect of a Surfactant Mixture on Coalescence Occurring in Concentrated Emulsions: The Hole Nucleation Theory Revisited

By conducting both a bottle test and isolate drop-drop experiments, we determine the coalescence rates of water droplets within water-in-oil emulsions stabilized by a large amount of Span 80 in the presence of Tween 20, a surfactant that acts as a demulsifier. Using a microscopic model based on a theory of hole nucleation, we establish an analytical formula that quantitatively predicts the coalescence frequency per unit area of droplets whose interfaces are fully covered by surfactant molecules. Despite its simplicity and the strong assumptions made for its derivation, this formula captures our experimental findings on Span 80-stabilized emulsions as well as other results, found in the literature, remarkably well on a wide range of water-in-crude oil systems.

Star amphiphilic block copolymers: synthesis via polymerization-induced self-assembly and crosslinking within nanoparticles, and solution and interfacial properties

The star amphiphilic block copolymer of star s-PNIPAM-b-PS is synthesized and it shows characteristics significantly different from those of the linear block copolymer counterpart.