基于双极膜电渗析的膜集成技术的高矿化度矿井水资源化处理

Resource utilization of high-salinity mine water through the membrane-integrated process based on bipolar membrane electrodialysis

在当前煤矿矿井水“零排放”及煤炭与水资源逆向分布背景下,西部矿区的高矿化度矿井水如若不进行合理处置便直接排放,不仅对当地生态环境造成不可估量的破坏,而且造成严重的水资源浪费,最终将制约煤炭绿色开发与生态文明建设。传统的高盐废水零排放技术主要是利用蒸发结晶技术将无机盐由溶液态转变为结晶态进行回收。从经济性方面分析,该技术受投资高、运行成本高、无机盐附加值低等问题制约。基于此,以西部某矿井水为原水,以矿井水资源化零排放利用及脱盐低碳化为目标进行膜集成工艺设计,并在此基础上重点探讨电渗析和双极膜电渗析工序不同操作条件(操作电压、进料液浓度、温度、酸碱度、电流密度等)对电渗析脱盐性能及双极膜电渗析制酸碱性能的影响规律,之后以实验数据及经济评估模型,探究其经济可行性,旨在探索出适用于西部矿区高矿化度矿井水处理的膜集成技术,为高矿化度矿井水绿色资源化处理工艺的开发提供新的研究思路。通过对电渗析−双极膜电渗析实验过程探究,发现双极膜系统进料液质量浓度应不超过80 g/L、适宜的操作电压为18 V、适宜的进料液温度为25℃、进料液pH保持中性、更适合采用恒电压操作。此外,证实了以双极膜电渗析为核心的膜集成系统可实现高矿化度矿井水绿色资源化处理,以电渗析系统进料液总含盐量20 g/L为例,总的净收益为18604299元/a,且在耦合光伏电力供应系统时具有明显的二氧化碳减排效应,二氧化碳减排将超过3162 t/a,具有良好的经济效益和社会效益。

In the context of“zero discharge”of mine water and the reverse distribution of coal and water resources in the western mining areas,the direct discharge of high-salinity mine water without proper treatment not only causes immeasurable damage to the local ecological environment,but also leads to serious water resource waste,ultimately constraining the green development of coal industry and the development of ecological civilization.The traditional zero discharge technology for high-salinity wastewater mainly relies on evaporation and crystallization to transform inorganic salts from a solution state to a crystalline state for recovery.From an economic perspective,this technology faces issues such as high investment,high operating costs,and low added value of inorganic salts.Based on this,this paper takes the mine water from a western mine as the raw water,aiming to achieve the resource utilization and desalination of mine water through the membrane integration technology,and focuses on exploring the influence of different operating conditions(operating voltage,feed solution concentration,temperature,acidity and alkalinity,current density,etc.)on the desalination performance of electrodialysis and the acid-base performance of bipolar membrane electrodialysis.Then,based on the experimental data and an economic evaluation model,the economic feasibility is explored,aiming to explore the membrane integration technology suitable for the treatment of high-salinity mine water in the western mining areas,and provide some new research ideas for the development of green resource utilization processes for high-salinity mine water.Through the exploration of the electrodialysis-bipolar membrane electrodialysis experimental process,it is found that the feed solution concentration of the bipolar membrane system should not exceed 80 g/L,the appropriate operating voltage is 18 V,the suitable feed solution temperature is 25℃,the feed solution pH should be kept neutral,and constant voltage operation is more suitable.In addition,it is confirmed that the membrane integration system centered on bipolar membrane electrodialysis can achieve the green resource utilization of high-salinity mine water.Taking the total salt content of the electrodialysis system feed solution as an example(20 g/L),the overall net profit is￥18604299 per year,and it has a significant carbon dioxide emission reduction effect when coupled with a photovoltaic power supply system,with a carbon dioxide emission reduction of over 3162 tons per year,demonstrating good economic and social benefits.