Lixin Wei

Crude oil emulsions are challenging to break due to their complex and variable composition. While high-performance demulsifiers exist, many conventional systems still face limitations such as poor stability under harsh conditions or insufficient separation efficiency for specific emulsion types. It is thus essential to develop new demulsifiers that combine high salt resistance with effective destabilization capability. Carbon materials, known for their strong adsorption capacity and chemical stability, can efficiently capture emulsified droplets, enabling significantly enhanced demulsification performance even under harsh conditions. The integration of TiO₂–carbon heterostructures with fluorinated polyether grafting into magnetic demulsifiers represents a previously unreported strategy. Building on this background, our research innovatively modified the magnetic substrate Fe₃O₄ by incorporating TiO₂ and three types of carbon materials (carbon nanospheres, graphene oxide, and carbon nanotubes). Through a sol–gel approach, fluorinated polyether chains were covalently grafted onto the surface of modified Fe₃O₄ nanoparticles, leading to the successful synthesis of three novel magnetic composite demulsifiers: Fe₃O₄@Ti/C–F, Fe₃O₄@Ti/G–F and Fe₃O₄@Ti/CN–F. The results demonstrate that these three demulsifiers exhibit excellent demulsification efficiency, acid resistance, and excellent recyclability. They achieve demulsification rates exceeding 85% in neutral and acidic environments. Notably, Fe₃O₄@Ti/G–F stands out with the best performance. After five cycles of recovery from a biphasic system, its demulsification efficiency remains above 70%. When used at a concentration of 600 mg L⁻¹, it can achieve a demulsification rate of 93.44% within just 30 minutes. In summary, this innovative magnetic nanodemulsifier not only provides an efficient and stable solution for crude oil emulsion separation but also offers significant ecological benefits, holding great potential for application in the treatment of oily wastewater.

The energy consumption issue of water injection systems has always been a key focus of energy conservation and consumption reduction in oilfield production. Optimizing the operational schemes of the water injection system is of great significance for achieving energy conservation and consumption reduction goals in oilfields. This article establishes a mathematical model for optimizing the operating parameters of oilfield water injection systems, with the operating parameters of water injection pumps as design variables and the objective function of minimizing water injection energy consumption. In the model, multiple constraints such as the balance of supply and demand of water within the station, pump flow rate, and injection well pressure are considered. Using the four defensive behaviors of the Crested Porcupine Optimizer (CPO) to optimize the Particle Swarm Optimization (PSO) Algorithm, a Multi-Mechanism Threat Response Strategy for Dynamic Parameter Adjustment is proposed to form a Hybrid Particle Swarm–Crested Porcupine Algorithm (PSCPA). Compared with the other nine algorithms, the PSCPA has better solving efficiency. Applying this method to a practical case of an old oilfield, the optimized water injection system scheme reduced power consumption by 11,719.23 KWh/d, increased the average pump efficiency of the system by 9.3%, and reduced system unit consumption by 0.37 KWh/d. Therefore, this algorithm has good practicality for optimizing the operation of large-scale and highly sensitive water injection systems.

By observing the microdroplet microstructure before and after demulsification, it is found that the Fe₃N@F magnetic demulsifier exhibits favorable coalescence, flocculation, and bridging capabilities.

Epoxy resin has become one of the most widely used polymers owing to their excellent comprehensive properties. However, the inherent inflammability of epoxy resin (EP) has seriously limited its application in a range of fields with high fire safety requirements. Herein, a novel shell–core hierarchy architecture (DAP@SiO₂) was prepared, composed of diammonium hydrogen phosphate (DAP) and in situ grown silica, and its structure and morphology were characterized by electron microscopy and infrared spectroscopy. The results indicated that silica particles were uniformly coated onto the surface of DAP. The modified DAP was used to reinforce the epoxy resin. The thermal stability of the EP blends was studied with the use of thermogravimetric analysis. The diammonium phosphate in DAP@SiO₂ flame retardant produces pyrolysis gases such as NH₃ and N₂ during decomposition, diluting the concentration of oxygen and flammable volatile products around the flame. Secondly, silica migrates to the surface of epoxy resin to form a shielding layer, forming compounds containing Si–O–Si and O–Si–C structures, which can be cross-linked with other condensed phase products, greatly improving the thermal stability of the carbon layer. Fire behavior was evaluated using the limiting oxygen index (LOI), vertical burning test, and the cone calorimetry, and the flame retardancy mode of action was explained. With 12% of DAP@SiO₂ involved, the EP blend passes UL-94 V-0 level, and its limiting oxygen index (LOI) reaches 33.2%. The incorporation of DAP@SiO₂ in an EP matrix showed a slight reduction in the heat release and smoke production. The flame retardant mode of the EP polymer shows that its flame retardant and smoke suppression characteristics are related to the interaction of flame retardants in the gas phase and condensed phase. The mechanical properties test results illustrated that the tensile strength, elastic modulus and impact strength of EP/3%DAP@SiO₂ are improved compared with pure EP. This is due to the crosslinking reaction between a large number of amino groups on the surface of DAP@SiO₂ and the epoxy group on the epoxy resin, which significantly enhances the interfacial compatibility between DAP@SiO₂ and epoxy resin, making the combination of DAP@SiO₂ and epoxy resin closer.

Based on the excellent adsorption properties of carbon materials, a new magnetic nanodemulsifier was prepared in this study. First, carbon nanotubes were oxidized using a solvothermal method. Then, Fe₃O₄ was combined with oxidized carbon nanotubes using a one-pot method, and then grafted onto fluorine-containing polyether to prepare a magnetic composite demulsifier (Fe₃O₄@C–F) with good demulsification properties. The surface morphology of the composite demulsifier was analyzed using scanning electron microscopy (SEM). The structure of the composite demulsifier was characterized using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). The stability of the composite demulsifier was characterized using thermogravimetric analysis (TGA). Results showed that the oxidized carbon nanotubes and fluorinated polyether were successfully attached to Fe₃O₄. The experimental objective was to obtain a self-made crude oil emulsion. The demulsification test and recovery performance test were then performed, and the main factors affecting the demulsification performance of the demulsifier were investigated. Results showed that when the dosage was 800 mg L⁻¹, the temperature was 65 °C, the demulsification time was 90 min, and the pH value was 6. The demulsification effect of the Fe₃O₄@C–F magnetic composite demulsifier was the best, whereby the demulsification rate could reach 91.68%, and the oil–water interface was clear. Fe₃O₄@C–F had a magnetic response and could be recycled from the two-phase system six times under the action of an external magnetic field. Fe₃O₄@C–F is an efficient and environmentally friendly demulsifier that has important application value for enriching demulsification technology systems.

In this study, a new type of highly efficient and recyclable magnetic-fluorine-containing polyether composite demulsifier (Fe₃O₄@G-F) was synthesized by the solvothermal method to solve the demulsification problem of oil–water emulsion. Fe₃O₄@G-F was successfully prepared by grafting fluorinated polyether onto Fe₃O₄ and graphene-oxide composites. Fe₃O₄@G-F was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Taking the self-made crude-oil emulsion as the experimental object, the demulsification mechanism of the demulsifier and the influence of external factors, such as the temperature and pH value, on the demulsification performance of the demulsifier are discussed. The results show that the demulsification efficiency of the Fe₃O₄@G-F emulsion can reach 91.38% within 30 min at a demulsifier dosage of 750 mg/L, pH of 6, and a demulsification temperature of 60 °C. In neutral and acidic environments, the demulsification rate of the demulsifier is more than 90%. In addition, Fe₃O₄@G-F has been proven to have good magnetic effects. Under the action of an external magnetic field, Fe₃O₄@G-F can be recycled and reused in a two-phase system four times, and the demulsification efficiency is higher than 70%. This magnetic nanoparticle demulsifier has broad application prospects for various industrial and environmental processes in an energy-saving manner.

In order to solve the problem of demulsification of oil-water emulsion, a new type of highly efficient and recyclable magnetic fluorine-containing polyether composite demulsifier (Fe₃O₄@Ti-F) was synthesized. Fe₃O₄@Ti-F was prepared by one-pot method to combine magnetic nanomaterial TiO₂ with Fe₃O₄ and graft fluorinated polyether. The successful synthesis of Fe₃O₄@Ti-F was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XPS). The demulsification performance of Fe₃O₄@Ti-F was evaluated by using the self-made crude oil emulsion as the experimental object. The demulsification mechanism of the demulsifier and the influence of external factors such as temperature and pH on the demulsification performance of the demulsifier were discussed, and the amount of TiO₂ in the preparation process was determined. The results show that the demulsification efficiency of 50:50 (v/v %) W/O emulsion can reach 90.83% when the dosage of Fe₃O₄@Ti-F is 600 mg/L, the temperature is 65 °C and the time is 30 min. In the neutral acid environment, the demulsification rate of the demulsifier is above 80%. In addition, Fe₃O₄@Ti-F has been proved to have good magnetic effect. Under the action of external magnetic field, it can be recovered and recycled from the two-phase system for 4 times, and its demulsification efficiency is still above 60%. Fe₃O₄@Ti-F will have broad application prospects in the field of oil-water separation in an energy-saving way. Graphical Abstract

In order to reduce the harmful effects of demulsifiers on the environment and provide a green and reusable demulsifier, a magnetic carbon nanosphere demulsifier (Fe3O4/CNNs) was prepared in this study. The morphology and structure of the Fe3O4/CNNs were characterized by scanning electron microscopy, Fourier transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that the magnetic demulsifier has uniform particles and good dispersibility. In addition, the demulsification experiments showed that the dehydration rate could reach 92% under the optimal demulsification conditions, and the residual water content of Fe3O4/CNN magnetic demulsifier increased by 0.11% in 8 cycles of recovery experiments. The demulsification mechanism of the demulsifier was speculated. This work showed that the compounded magnetic demulsifier is friendly to the environment and is an effective material for separating oil and water phases, with broad application prospects.