Abstract:

A stable emulsion was prepared by using dichloroethane as the dispersed phase and water as the continuous phase.Agglomeration and demulsification of the emulsion in ultrasonic standing wave field were studied.The factors affecting demulsification, such as ultrasound intensity, treating time, sedimentation time, ultrasonic frequency, were investigated.The results showed that the change of ultrasound directly affected the cohesion and dispersion of the particles, and ultrasound intensity should be lower than a critical value.The treating time also should be lower than a critical value.The equation for calculating the best ultrasonic frequency was proposed, and the experimental results verified the calculated best ultrasonic frequency.The orthogonal experiment was designed by considering energy consumption and demulsification efficiency.The optimum experimental conditions of the demulsification were ultrasonic frequency of 10 kHz，sound intensity of 270 W• m^-2，irradiation time of 9 min，sedimentation temperature of 40℃ and sedimentation time of 3 h.Under the optimum experimental conditions, the demulsification efficiency could reach 91%.

Key words:

超声波, 驻波场, 乳状液, 凝聚, 破乳

摘要：

以水为连续相、二氯乙烷为分散相，配制成稳定的乳状液，在超声驻波场条件下，对其进行凝聚破乳研究，重点考察超声声强、超声辐照时间、沉降时间、超声作用频率对乳状液破乳的影响。结果表明，超声声强的改变直接影响了乳状液分散相液滴的凝聚和发散，超声破乳的声强应在临界阈值以下;超声辐照时间存在一个最佳作用时间;超声频率对液滴凝聚有重要影响，根据体系黏度、密度、液滴粒径等性质计算了最佳超声凝聚频率，并通过了实验验证。设计了正交实验，综合考虑了能耗和破乳效率，得到该乳状液破乳最佳条件为：超声频率10 kHz、声强270 W•m^-2、辐照时间9 min、沉降温度40℃及沉降时间3 h。此条件下，其破乳率可达到91%。

关键词:

超声波, 驻波场, 乳状液, 凝聚, 破乳