钙镁二元盐复合材料的储热性能  

Evaluation of the thermal energy storage performance of calcium-magnesium binary composite salt hydrates

作　　者：刘涵 曲明璐[1] 叶振东 杨帆 黄蓓佳[1] 张亚宁[2] 刘洪芝 LIU Han;QU Minglu;YE Zhendong;YANG Fan;HUANG Beijia;ZHANG Yaning;LIU Hongzhi(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150006,Heilongjiang,China;Hokkaido University,Faculty of Engineering,Hokkaido Sapporo 0608628,Japan)

机构地区：[1]上海理工大学环境与建筑学院,上海200093 [2]哈尔滨工业大学能源科学与工程学院,黑龙江哈尔滨150006 [3]北海道大学大学院工学研究院,北海道札幌0608628

出　　处：《化工进展》2024年第4期1764-1773,共10页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金青年基金(51906157);国家自然科学基金面上项目(71974129)。

摘　　要：水合盐热化学储热利用可逆的化学反应,能够在吸附与脱附过程中实现热量的释放与储存,其具有储热密度高、适合长期跨季节储热等优点,与太阳能相结合可以减少对化石能源的依赖。为探究两种不同多孔基底对钙镁二元盐复合热化学储热材料储热性能的影响,基于摩尔比为1∶2的MgCl_(2)与CaCl_(2)两种水合盐,本文对以微孔分子筛(13X)为多孔基底的MgCl_(2)/2CaCl_(2)复合材料和以介孔硅藻土(WSS)为多孔基底的MgCl_(2)/2CaCl_(2)复合材料的孔结构、平衡吸附量和循环稳定性等进行实验对比分析。采用蜂窝状储热单元的二维模型,对两种MgCl_(2)/2CaCl_(2)复合热化学储热单元的储/放热过程进行模拟对比分析。结果表明,与WSS相比,13X的孔隙更小、比表面积更大、平衡吸附量更高。由于MgCl_(2)/2CaCl_(2)的填充,两种复合材料的孔体积、比表面积、孔隙率较多孔基底均有所下降。受MgCl_(2)/2CaCl_(2)与多孔基底协同作用的影响,MgCl_(2)/2CaCl_(2)复合材料的平衡吸附量在整个相对湿度区间均有明显提升,Polanyi吸附势理论可以很好地描述MgCl_(2)/2CaCl_(2)复合材料的等温吸附线。WSS20储热单元的储热密度为371.94MJ/m^(3),可以持续输出20℃温升以上的空气198min,其放热功率和热回收效率均高于13X17储热单元。WSS20在循环47次后仍然保持完整的结构和良好的吸附量,而13X17在循环10次后发生破裂。综合储热密度和循环稳定性,WSS20更适合作为储热材料使用。Salt hydrate as a type of thermochemical energy storage materials involves reversible chemical reactions for the storage and release of heat during the processes of adsorption and desorption.It has high thermal energy storage density and is suitable for long-term thermal energy storage.Moreover,it can be combined with solar energy utilization,which can reduce the dependence on fossil energy.In this study,effect of different porous matrix,microporous molecular sieve(13X)and mesoporous diatomaceous earth(WSS)on the thermal energy storage performance of calcium-magnesium binary composite salt hydrates was investigated based on MgCl_(2)and CaCl_(2)with a molar ratio of 1∶2.Firstly,the pore structure,sorption isotherm and cycle stability of the developed two types of calcium-magnesium binary composite salt hydrates were compared.A two-dimensional model of a honeycomb thermal energy storage unit was used to analyze the storage/release performances of the developed two composites.Results showed that the 13X had smaller pore volume,larger specific surface area than WSS.Due to the impregnation of MgCl_(2)/2CaCl_(2),the pore volume,specific surface area and porosity of calcium-magnesium binary composite salt hydrates had been reduced compared to those of corresponding porous matrix.Both MgCl_(2)/2CaCl_(2)composites showed higher sorption capacity than that of the porous matrix.Moreover,the Polanyi adsorption potential theory could describe the sorption isotherm of the calcium-magnesium binary composite salt hydrates well.Furthermore,the simulation results showed that the thermal energy storage density of the WSS20 was 371.94MJ/m^(3),which was higher than that of 13X17,as well as the energy released power and recovery efficiency.The WSS20 could be used for storing/releasing thermal energy more than 47 times,while the 13X17 showed bad stability even within 10 cycles.Therefore,considering both thermal energy storage density and cycle stability,WSS20 was more suitable for storing thermal energy.

关 键 词：热化学储热 钙镁二元盐 硅藻土 循环稳定性 储热密度 

分 类 号：TK11[动力工程及工程热物理—热能工程]