Mass Transfer from Single Drops and the Influence of Temperature

• Published in: Industrial & engineering chemistry research Vol. 51; no. 21; pp. 7364 - 7372
• Main Authors: Saien, Javad, Daliri, Shabnam
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 30.05.2012
• Subjects: Applied sciences; Chemical engineering; Diffusivity; Dispersion; Drop size; Empirical equations; engineering; equations; Exact sciences and technology; Heat and mass transfer. Packings, plates; Liquid-liquid extraction; Mass transfer; Mathematical analysis; Mathematical models; temperature; terminal velocity; Mass transfer; Drop
• DOI: 10.1021/ie300649d
• ISSN: 0888-5885; 1520-5045

Temperature can alter the performance of conventional liquid–liquid extraction columns in which one phase is dispersed inside another phase. In this research, the influence of temperature on the extraction process was investigated using a toluene–acetic acid–water chemical system with dominant mass transfer resistance in the organic phase. Single drop experiments with a range of drop size within 2.49–3.77 mm and temperature within 15–40 °C were performed. Results demonstrate significant impact of temperature on the rate of mass transfer with an average enhancement of 93.6% in overall mass transfer coefficient while small drops are benefited more. Having lower contributions by drop size and terminal velocity, the extraction efficiency is the most effective term in this regard which itself is increased by increasing molecular diffusivity in the organic dispersed phase. For the aim of modeling, effective diffusivity was substituted for molecular diffusivity in Newman’s equation and consequently, a reliable empirical equation was derived for the enhancement factor of diffusivity as a function of dimensionless variables.