基于电渗析的溶液再生传质模型及性能分析

Mass transfer model and performance analysis of liquid desiccant regeneration by electrodialysis

电渗析溶液再生与传统热再生相比具有较大的节能潜力,近年来受到了越来越多的关注。目前有关电渗析溶液再生的研究主要都集中在系统层面的分析,而缺乏对电渗析传质机理的认识。为此,建立了描述电渗析在高浓度下的传质理论模型,并试验探究了不同电流密度、体积比及初始浓度对系统性能的影响。结果表明,模型和试验结果吻合很好,误差小于±4%。体积比越大时,系统再生性能越好,但溶液产量也越低;电流密度越大时,系统再生性能越好,但系统能耗也越高;初始浓度越高时,系统电流效率和再生性能越低,同时膜堆中浓差极化系数也越低。在实际应用时应权衡以上因素以实现更高的系统性能和效率。

Compared with the traditional thermal regeneration,electrodialysis(ED)regeneration has greater energy saving potential and has attracted more and more attention in recent years.At present,the research on the regeneration of ED solution is mainly focused on the system analysis,and there is a lack of the understanding of mass transfer mechanism in ED.To this end,a theoretical model describing the mass transfer in ED at high salt concentrations was established,and the effects of different current densities,volume ratios and initial concentrations on system performance were experimentally investigated.The results show that the model and the experimental results are in good agreement,and the errors are less than±4%.The larger the volume ratio,the better the system regeneration performance,but the lower the solution production;the larger the current density,the better the system regeneration performance,but the higher the energy consumption;the higher the initial concentration,the lower the current efficiency and regeneration performance of the system,and the lower the concentration polarization coefficient.In practical applications,the above factors should be balanced to achieve higher performance and efficiency of system.