碳酸氢铵-反向电渗析模块构型研究

The configuration of reverse electrodialysis stacks utilizing ammonium bicarbonate solutions

为了提高碳酸氢铵-反向电渗析模块的产电性能,对其构型进行了优化,并分析了其能量效率的变化特点.结果表明,当碳酸氢铵-反向电渗析模块采用5对离子交换膜及0.2mm厚的隔板时,其功率密度可达最大值0.85W/m2(不计电极系统能量损耗).膜对数量不超过8时,开路电压、内阻及最大功率密度均随膜对数的增加而逐渐升高,且膜对数与开路电压、内阻均呈现出良好的线性关系;膜对数量大于8时,装置产电性能逐渐变差.对于相同种类的隔板,采用较薄的隔板能减小装置的内阻,其产电性能更好;对于同等厚度的隔板,编织结构紧密的隔板更优.实验中装置能量效率稳定于30%左右,表明其在能量利用方面具有一定优势.

The configuration of a reverse electrodialysis （RED） stack utilizing ammonium bicarbonate solution was optimized in order to improve the power output.The variation of energy efficiency was also analyzed.The results showed that a maximum power density of 0.85 W/m2 was achieved with the use of five cell pairs and a spacer with a thickness of 0.2 mm when ignoring the power consumption due to the electrode system.When the number of cell pairs ranged from 2 to 8,the open circuit voltage,internal resistance and maximum power density all improved gradually with increasing number of cell pairs.Meanwhile,the number of cell pairs had a good linear relationship with both the open circuit voltage and internal resistance.However the RED stack had a reduced power output when the number of cell pairs was over 8.For two spacers with the same type,the thinner one resulted in a decreased internal resistance and thus increased the power output.For the spacers with the same thickness,the one with a compact woven structure performed better.Energy efficiency of the RED stack stabilized at about 30% during the experiment,which shows its promise for energy utilization.