What is A Demulsifier?
A demulsifier, also known as an emulsion breaker, is a chemical additive used to separate or “break” emulsions (water-in-oil or oil-in-water emulsions) into distinct oil and water phases. Demulsifiers are commonly employed in the processing of crude oil, which is typically produced along with significant quantities of saline water. This water and salt must be removed from the crude oil prior to refining to prevent corrosion and other issues downstream.
Types of Demulsifiers
Demulsifiers can be classified based on their chemical structure and composition. The main types include:
- Alkoxylated alkylphenol-aldehyde resins: A widely used class of demulsifiers with various varieties. They are effective for breaking water-in-oil emulsions from produced fluids.
- Polyalkoxylate block copolymers and their ester derivatives: These copolymers, such as Pluronic® and Tetronic®, are triblock copolymers of polyoxyethylene-polyoxypropylene-polyoxyethylene (POE-POP-POE) or polyoxypropylene-polyoxyethylene-polyoxypropylene (POP-POE-POP).
- Polyalkoxylates of polyols: Polyalkoxylated polyols, including glycerol-based block copolymers with molecular weights of 3000-6000, are effective demulsifiers.
- (Polyalkoxylated) polyamines and their amide derivatives: These nitrogen-containing compounds, such as diethanolamine, triethanolamine, and piperidine, can be combined with nonionic surfactants for demulsification.
- Nitrogen-based cationic surfactants or polymers
- (Polyalkoxylated) polyurethanes
- Hyperbranched polymers
- Alkoxylated vinyl polymers
- Polysilicones
- Polyalkoxylate-polysiloxane block copolymers
Production of Demulsifier
Polyester demulsifiers are widely used for crude oil treatment, typically prepared by polycondensation of poly(tetrahydrofuran) and polyalkylene glycols with adipic acid and p-toluenesulfonic acid as a catalyst. The reaction is carried out under nitrogen purging at around 170°C. These demulsifiers exhibit superior performance compared to commercial products, with thief grindout residual emulsion values of 1.9-4.0 and free water values of 5.0-36.0.
Cationic polyether demulsifiers with a network structure can be prepared by reacting bisamide with epichlorohydrin. The raw materials are readily available, and the preparation process is simple with low equipment requirements. These demulsifiers have a special network structure and strong surface activity, providing excellent demulsification performance for chemical flooding-produced liquids, with an oil removal rate of over 98% at a dosage of 20-30 mg/L.
Uses of Demulsifiers
Demulsifier Applications in Crude Oil Processing
- Demulsifiers are used to break water-in-oil or oil-in-water emulsions formed during crude oil production and processing, separating the oil and water phases. This is crucial for:
- Preventing equipment corrosion, high pressure drops, and catalyst poisoning
- Meeting transportation and refinery requirements for low water content (typically <0.5-3%)
- Demulsification is often performed at the earliest stages after extraction, such as offshore platforms, to avoid storing/shipping emulsified crude.
- Specific demulsifier compositions are designed for different types of crude oil emulsions based on factors like water content, interfacial properties, etc.
Demulsifier Use in Other Industries
- Hydraulic fracturing: Demulsifiers break emulsions that increase fracturing fluid viscosity, reducing formation permeability and production.
- Bioprocessing: Demulsifiers separate aqueous/organic emulsions to extract desired bioproducts like pharmaceuticals, fuels, etc.
- Lubricating oils: Demulsifiers prevent water contamination and emulsion formation in engine lubricants.
Application Case
| Product/Project | Technical Outcomes | Application Scenarios |
|---|---|---|
| Demulsifier for Crude Oil Processing | Effectively separates water-in-oil emulsions formed during crude oil production, reducing equipment corrosion, pressure drops, and catalyst poisoning. Enables meeting transportation and refinery requirements for low water content (typically <0.5-3%). | Offshore platforms and early stages of crude oil extraction to prevent storing/shipping emulsified crude. |
| Demulsifier for Hydraulic Fracturing | Breaks emulsions that increase fracturing fluid viscosity, improving formation permeability and production rates. | Oil and gas well stimulation through hydraulic fracturing operations. |
| Demulsifier for Bioprocessing | Separates aqueous and organic phases in fermentation broths, facilitating downstream processing and product recovery. | Biotechnology and pharmaceutical industries for purification of fermentation products. |
| Demulsifier for Metalworking Fluids | Prevents formation of stable emulsions in metalworking fluids, reducing fluid degradation, extending fluid life, and improving surface finish. | Metalworking operations such as cutting, grinding, and drilling, where coolants and lubricants are used. |
| Demulsifier for Wastewater Treatment | Breaks stable oil-water emulsions in industrial wastewater, enabling efficient separation and treatment of the water phase before discharge. | Industrial facilities generating oily wastewater, such as refineries, petrochemical plants, and metal processing plants. |
Latest innovations in Demulsifier
Novel Demulsifier Compositions
- Environmentally friendly demulsifiers based on natural materials like alkanolamides, polyglycols, fatty acids, and their derivatives. These are more eco-friendly alternatives to conventional phenolic demulsifiers.
- Quaternary organopolysiloxanes and their salts as effective demulsifiers for separating oil-water emulsions, optionally combined with quaternary epihalohydrin/polyamine copolymers or (poly)diallyldimethylammonium halides.
- Microemulsion-based demulsifier compositions containing nonionic surfactants, coupling agents, additional surfactants, and nonionic emulsifiers.
- Demulsifiers incorporating dendrimers or dendritic polymers, which exhibit high interfacial activity and improved performance compared to linear polymers.
Mechanisms and Performance Optimization
- Strong hydrogen bonding interactions between demulsifiers and water molecules, enabling effective breaking of asphaltene-stabilized water-in-oil emulsions.
- Tailoring demulsifier structure and composition to modulate hydrophilic-lipophilic balance (HLB) and interfacial properties for improved demulsification efficiency.
- Optimizing demulsifier concentration, temperature, and reaction time to enhance performance.
- Novel core-shell polymer nanoparticles that can destabilize both water-in-oil and oil-in-water emulsions by interfacial substitution and suppression of steric repulsion.
Emerging Trends
- Combination of chemical demulsification with physical methods (e.g., centrifugation, thermal treatment, membrane separation) for improved efficiency.
- Development of high-performance, cost-effective, and environmentally friendly demulsifiers as a key research focus.
- Exploration of emerging alternatives like nanoparticle-based demulsifiers and ionic liquids for demulsification applications.
Technical challenges
| Novel Demulsifier Compositions | Developing novel demulsifier compositions with improved environmental friendliness, enhanced performance, and tailored properties for effective demulsification of water-in-oil and oil-in-water emulsions. |
| Demulsification Mechanisms and Performance Optimization | Elucidating the mechanisms by which demulsifiers interact with emulsions, and optimizing their performance through structural modifications, formulation adjustments, and synergistic combinations. |
| Environmentally Friendly and Biodegradable Demulsifiers | Exploring the use of natural materials, renewable resources, and biodegradable compounds as demulsifier components to reduce environmental impact and enhance sustainability. |
| Dendritic and Hyperbranched Polymer Demulsifiers | Developing dendritic and hyperbranched polymer architectures as demulsifiers, leveraging their unique structural features for improved interfacial activity and demulsification efficiency. |
| Nanoparticle-Based Demulsifiers | Investigating the potential of nanoparticles, either alone or in combination with polymeric demulsifiers, for enhanced demulsification performance and tailored interfacial properties. |
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