The dynamic interfacial adsorption and demulsification behaviors of novel amphiphilic dendrimers

Novel polymer nanoparticles with core-shell structure for breaking asphaltenes-stabilized W/O and O/W emulsions

HYPOTHESIS

The removal of stable water-in-oil (W/O) or oil-in-water (O/W) emulsions has been a challenging issue in chemical and oil industry for decades. Traditional demulsifiers were generally designed specifically for treating either W/O or O/W emulsions. A demulsifier that is effective for treating both types of emulsions will be highly desired.

EXPERIMENTS

Novel polymer nanoparticles (PBM@PDM) was synthesized as a demulsifier for treating both W/O and O/W emulsions prepared by toluene, water, and asphaltenes. The morphology and chemical composition of synthesized PBM@PDM were characterized. Demulsification performance and interaction mechanisms including interfacial tension, interfacial pressure, surface charge properties and surface forces were systematically studied.

FINDINGS

PBM@PDM could immediately prompt the coalescence of water droplets upon addition and effectively release the water in asphaltenes-stabilized W/O emulsion. In addition, PBM@PDM successfully destabilized asphaltenes-stabilized O/W emulsion. Not only could PBM@PDM substitute the asphaltenes adsorbed at the water-toluene interface, but they could also dominate the water-toluene interfacial pressure in competition with asphaltenes. The steric repulsion between interfacial asphaltene films could be suppressed in the presence of PBM@PDM. Surface charges significantly influenced the stability of asphaltenes-stabilized O/W emulsion. This work provides useful insights into the interaction mechanisms of asphaltene-stabilized W/O and O/W emulsions.

Investigation of Dioctyl Sodium Sulfosuccinate in Demulsifying Crude Oil-in-Water Emulsions

This research investigated the performance of dioctyl sodium sulfosuccinate (DSS), a double-chain anionic surfactant, in breaking crude oil-in-water emulsions. The response surface methodology was used to consider the effect of the DSS concentration, oil concentration, and shaking time on demulsification efficiency and obtain optimum demulsification conditions. Further single-factor experiments were conducted to investigate the effects of salinity, crude oil conditions (fresh and weathered), and gravity separation settling time. The results showed that DSS efficiently demulsified stable emulsions under different oil concentrations (500-3000 mg/L) within 15 min shaking time. Increasing DSS concentration to 900 mg/L (critical micelle concentration) increased the demulsification efficiency to 99%. DSS not only improved the demulsification efficiency but also did not impede the demulsifier interfacial adsorption at the oil-water interface due to the presence of the double-chain structure. The low molecular weight enables the homogeneous distribution of DSS molecules in the emulsion, leading to a high demulsification efficiency within 15 min. Analysis of variance results indicated the importance of considering the interaction of oil concentration and shaking time in demulsification. DSS could reduce the total extractable petroleum hydrocarbons in the separated water to <10 mg/L without gravity separation and could achieve promising demulsification performance at high salinity (36 g/L) and various concentrations of fresh and weathered oil. The demulsification mechanism was explained by analyzing the microscopic images and the transmittance of the emulsion. DSS could be an efficient double-chain anionic surfactant in demulsifying stable oil-in-water emulsions.

Recent developments, challenges, and prospects of ultrasound-assisted oil technologies

There has been consistent drive towards research and innovation in oil production technologies in order to achieve improved effectiveness and efficiency in their operation. This drive has resulted in breakthrough in technologies such as the application of ultrasound (US) in demulsification and enhanced oil recovery (EOR), and usage of high-volume hydraulic fracturing and special horizontal well for shale oil and gas extraction. These can be observed in the increment in the number of commercial oil technologies such as EOR projects that rose from 237 in 1996 to 375 in 2017. This sustained expansion in EOR resulted in their total oil production rising from 1.5 million barrels per day in 2005 to 2.3 million barrels per day in 2020. And this is predicted to increase to about 4.7 million barrels per day in 2040, which represent about 4% of total production. Consequently, in this review, the developments in the utilization of US either as standalone or integrated with other technologies in EOR and dehydration of water in oil emulsions were analyzed. The studies include the optimization of fluid and US properties in EOR and demulsification. Reports on the treatment of formation damage resulting from inorganic salts, organic scales, drilling fluid plugs, condensate, paraffin wax and colloidal particle with US-assisted EOR were also highlighted. Moreover, the mechanisms were examined in order to gain insightful understanding and to aid research investigations in these areas. Technologies such as US assisted green demulsification, high intensity focused ultrasound, and potential pathways in field studies were assessed for their feasibilities. It is essential to evaluate these technologies due to the significant accrued benefits in them. The usage of green demulsifiers such as deep eutectic solvents, ionic liquids and bio-demulsifiers has promising future outlook and US could enhance their technical advancement. HiFU has been applied successfully in clinical research and developments in this area can potentiality improve demulsification and interfacial studies (fluid-fluid and solid-fluid interactions). As regards field studies, there is need to increase actual well investigations because present reports have few on-site measurements with most studies being in laboratory scale. Furthermore, there is need for more detailed modeling of these technologies as it would assist in conserving resources, saving research time and fast-tracking oil production. Additional evaluative studies of conditions such as the usage of Raschig rings, crude oil salinity and high temperature which have improved demulsification of crude oil emulsions should be pursued.

The Demulsification Properties of Cationic Hyperbranched Polyamidoamines for Polymer Flooding Emulsions and Microemulsions

Polymer flooding emulsions and microemulsions caused by tertiary oil recovery technologies are harmful to the environment due to their excellent stability. Two cationic hyperbranched polyamidoamines (H-PAMAM), named as H-PAMAM-HA and H-PAMAM-ETA, were obtained by changing the terminal denotation agents to H-PAMAM, which was characterized by 1H NMR, FT-IR, and amine possession, thereby confirmed the modification. Samples (300 mg/L) were added to the polymer flooding emulsion (1500 mg/L oil concentration) at 30 °C for 30 min and the H-PAMAM-HA and H-PAMAM-ETA were shown to perform at 88% and 91% deoil efficiency. Additionally, the increased settling time and the raised temperature enhanced performance. For example, an oil removal ratio of 97.7% was observed after dealing with the emulsion for 30 min at 60 °C, while 98.5% deoil efficiency was obtained after 90 min at 45 °C for the 300 mg/L H-PAMAM-ETA. To determine the differences when dealing with the emulsion, the interfacial tension, ζ potential, and turbidity measurements were fully estimated. Moreover, diametrically different demulsification mechanisms were found when the samples were utilized to treat the microemulsion. The modified demulsifiers showed excellent demulsification efficiency via their obvious electroneutralization and bridge functions, while the H-PAMAM appeared to enhance the stability of the microemulsion.

Efficient Demulsification of Acidic Oil-In-Water Emulsions with Silane-Coupled Modified TiO2 Pillared Montmorillonite

Emulsified pickling waste liquid, derived from cleaning oily hardware, cause serious environmental and ecological issues. In this work, a series of grafted (3-aminopropyl)triethoxysilane (APTES) TiO2 pillared montmorillonite (Mt), Ti-Mt-APTES, are prepared and characterized for their assessment in demulsification of acidic oil-in-water emulsion. After titanium hydrate is introduced through ion exchange, montmorillonite is modified by hydrophobic groups coming from APTES. The Ti-Mt-APTES in acidic oil-in-water emulsion demulsification performance and mechanism are studied. Results show that the prepared Ti-Mt-APTES has favorable demulsification performance. The Ti-Mt-APTES demulsification efficiency (ED) increased to an upper limit value when the mass ratio of APTES to the prepared TiO2 pillared montmorillonite (Ti-Mt) (RA/M) was 0.10 g/g, and the 5 h is the optimal continuous stirring time for breaking the acidic oil-in-water emulsion by Ti-Mt-APTES. The ED increased to 94.8% when 2.5 g/L of Ti-Mt-APTES is added into the acidic oil-in-water emulsion after 5 h. An examination of the demulsification mechanism revealed that amphiphilicity and electrostatic interaction both played vital roles in oil-in-water separation. It is demonstrated that Ti-Mt-APTES is a promising, economical demulsifier for the efficient treatment of acidic oil-in-water emulsions.

Ethyl cellulose nanodispersions as stabilizers for oil in water Pickering emulsions

Ethyl cellulose (EC) nanodispersions have been prepared through a facile procedure, a process involved the dissolution of EC into ethanol, followed by dipping it in Xanthan Gum (XG) solution (0.1%, used as anti-solvent), and then removed the ethanol. The influences of preparation conditions on the structure and properties of the EC nanodispersions were investigated. The prepared EC nanodispersion had a negative surface potential, which contributed to its stabilization. The particle size of the nanodispersions could be controlled by changing the concentration of EC. Furthermore, the EC nanodispersions had a potential application for the stabilization of oil/water Pickering emulsion. The obtained Pickering emulsions showed high stability.