Ammonia absorption in ionic liquids-based mixtures in plate heat exchangers studied by a semi-empirical heat and mass transfer framework

Abstract

Unfavorable transport properties have always been pointed out as the key factors that hinder the application of ammonia/ionic liquids (NH
₃
/ILs) in absorption cycles, while heat and mass transfer of these new fluids in components have been rarely reported. In this study, a corrugated plate heat exchanger is selected as the geometry for exploring the absorption of NH
₃
in the proposed NH
₃
/ILs working fluids. The process is studied making use of a semi-empirical framework: experimental data is needed to determine unknown information of heat and mass transfer, and a numerical model is developed making use of frequently applied theories. In addition, relevant transport properties of the NH
₃
/ILs working fluids are modeled based on collected experimental data. The proposed model is used to study the heat and mass transfer performance during the absorption of NH
₃
vapor into NH
₃
/ILs fluids. Distribution of local parameters and overall heat and mass transfer characteristics are obtained. The performance of absorption of NH
₃
into different working fluids is investigated as well. The overall heat transfer coefficient is found around 1.4 kW/(m
²
·K) for the most promising working fluid NH
₃
/[emim][SCN].