A facile synthesis of low-temperature polyamine-based demulsifiers for the treatment of crude oil emulsions

In this study, polyethylene polyamine was used as the hydrophilic center, while alkyl glyceryl ethers served as hydrophobic tails, leading to the synthesis of various polyamine-based demulsifiers through a simple one-step method. The bottle test method was employed to assess their demulsification efficiency (DE) in the water-in-crude oil system, and their RSN values were measured through titration experiments. The results indicated that under conditions of 300 mg/L concentration and 40 °C, the DE of TE-8 and PE-8 reached 95.8 % and 98.63 %, respectively, without the need for additional additives. Furthermore, it was found that under general conditions, the DE increased continuously as the RSN value of the polyamine-based demulsifiers approached a certain value. Detailed demulsification experiments on TE-8 demonstrated that these types of demulsifiers exhibited excellent salt and acid-base tolerance. Additionally, the demulsification mechanism of TE-8 was inferred through its interfacial activity, competitive adsorption behaviour, and interfacial film strength. Evidence suggested that TE-8 effectively replaced the asphaltenes at the interface, thereby weakening the strength of the interfacial film and promoting the coalescence of water droplets.