| The stability has been a basic scientific problem of a great concentration in the field of emulsion, but the mechanism of the emulsion stability was chiefly clarified by determination of interface tension, interfacial film strength and surface pressure in the past. In recent years, more and more research has shown that it’s not enough to clarify the emulsion stability mechanism if only from the two aspects of interfacial tension and interfacial film strength, the dilatational viscoelasticity properties of interface film has important influence on the emulsion stability.According to the characteristics of emulsion membrane separation system, the dilational viscoelastic properties of two emulsion membrane systems, Span-80/decane/water and OP-4/decane/water, were studied by means of oscillating barriers method in this thesis. The effects of dilatational frequency, emulsifier concentration, extraction solvent and temperature on the dilatational viscoelasticity properties were studied. Furthermore, the correlation between the stability of the emulsion films and the interfacial dilatational elasticity of the respective monolayer was also discussed. In order to meet the needs of the demulsification of crude oil, three kinds of demulsifiers were synthesized and qualitatively charactered, and Some advice of further studies for dilatational theological viseoelastieity and how to improve the performance of demulsifier are presented. The main conclusions are as follows:1. The influence of the dilatational frequency. With the increase of the dilatational frequency, all the dilational modulus, dilational elasticity and dilational viscosity of Span-80interfacial film increase, for the phase angle, it increases firstly and then decreases, appears a maximum value. The OP-4interfacial film also shows the same rules, but Span-80interfacial film showed higher elasticity than that of OP-4.2. The influence of emulsifier concentration. When the dilatational frequency fixed at0.1Hz, with the increase of Span-80concentration, the dilational modulus, dilational elasticity and dilational viscosity increase, but it shows opposite trend for OP-4.3. The influence of the temperature. With the increase of the temperature, all the dilatational modulus, dilatational elasticity and dilatational viscosity of span-80interfacial film and OP-4interfacial film decrease; for the phase angle, it increases firstly and then decreases.4. The influence of the extractant. When two kinds of extractants P204and TBP were formed composite film with Span-80or OP-4respectively, the dilational elasticity of Span80/P204and OP-4/P204composite film decrease, compared to the pure Span-80interfacial film or OP-4interfacial film, means that the film strength become weak. On the contrary, the interfacial viscosity increased. Span-80/TBP and OP-4/TBP composite film have a similar trend, but show a greater change. For the phase angle, it has the same results Span-80/TBP and OP-4/TBP composite film relative to that of pure film.5. The influence of the water phase. Compared with pure water phase, when the water phase is instead by HC1dilute solution or, the dilatational modulus, dilational elasticity and dilational viscosity of Span-80interfacial film and OP-4interface film decrease. When the water phase is instead by NaOH dilute solution, the dilatational modulus, dilational elasticity and dilational viscosity of Span-80interfacial film decrease, but they increase for the OP-4interfacial film.6. Three kinds of demulsifier Maleic acid polyether-styrene-Methyl Acrylate-Acrylate copolymer、Maleic acid polyether-styrene-Methyl Acrylate-Acrylate copolymer Ammonium Salt、 Maleated Rosin Tri-quaternary Ammonium Salt were synthesized, and were applied to the demulsification test for simulation crude oil emulsion. The results prove that three samples have a better demulsification. |
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