STUDY OF PARAMETERS AFFECTING THE COALESCENCE OF DIMETHYL DISULFIDE DROPS IN A MEROX UNIT

Mohammad Kasmaee,Parissa Khadiv-Parsi,Javad Saien,Farshad Varaminian

doi:10.1590/0104-6632.20190364s20180569

Abstract

Abstract This study focuses on the coalescence of dimethyl disulfide drops with the mother phase at a flat aqueous-organic interface between dimethyl disulfide and different sodium hydroxide solutions. Drop coalescence is an important part of the Merox process for regenerating the solvent. A digital high-frame rate camera was used for recording drops coalescence and duration time. Drops of dimethyl disulfide were directed in different sodium hydroxide solutions as the continuous phase. Applying the experimental design method, the influences of independent variables of drop size and physical properties on coalescence time were investigated. Computational fluid dynamics (CFD) was employed to simulate the drops released from a nozzle, moving toward the interface, and the CFD results were validated by experimental data. The maximum deviation between the predicted and experimental coalescence times was 18.7%. It was found that, among the physical properties, interfacial tension plays the most important role on the coalescence time. Based on the results, a correlation for coalescence time was proposed.

Highlights

Coalescence of drops with their mother phase has been studied widely over the past decades (Kavehpour, 2015)
Focus on gravity separators with the aim of separation of two immiscible liquid phases and the study of the coalescence time of drops with the mother phase are of high importance, in the oil industry (Paul, Atiemo-Obeng et al, 2004)
The early works corresponds to Charles and Mason (1960), who investigated the coalescence time and reported that, in an oil/water system, stability increases with increasing drop size and with decreasing temperature

Summary

Introduction

Coalescence of drops with their mother phase has been studied widely over the past decades (Kavehpour, 2015). The drop-interface coalescence process has been the subject of several works and considerable theoretical and experimental studies have been performed in this regard. The early works corresponds to Charles and Mason (1960), who investigated the coalescence time and reported that, in an oil/water system, stability increases with increasing drop size and with decreasing temperature. Davis et al (1971) investigated the symbolic design of the stages of coalescence and their corresponding times. They found that the coalescence takes place in four consecutive stages: collision of liquid bodies, drainage of the narrow film trapped between them, rupturing of the film and eventual coalescence.

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Conclusion