Research on technology and process for moderate desalination of high-salinity mine water by nanofiltration
GE Guangrong,WU Yiping, ZHANG Quan
高矿化度矿井水在我国西部矿区普遍存在。近年来随着煤炭西进战略的实施,该区域的干旱、水污染和生态退化问题日益凸显,迫使关于高矿化度矿井水资源化和达标排放的政策法规日益趋严,进而倒逼高矿化度矿井水节能高效脱盐技术不断发展。为进一步提高西部矿区高矿化度矿井水的资源化利用水平、降低脱盐成本,基于广泛的矿井水水质水量、分布现状和脱盐技术现状调研,针对现阶段高矿化度矿井水脱盐主流技术因非选择性脱盐和单纯追求高脱盐率而产生的过度脱盐、工艺复杂、高能耗、膜污染等问题,提出针对煤矿区溶解性总固体(TDS)在1 000~3 000 mg/L微咸矿井水分级分质回用适度脱盐工艺。
适度脱盐核心是对矿井水中特定离子(如Ca2+、Mg2+、SO42-等)进行有选择性的脱除,在满足相关水质要求前提下使脱盐成本最小化,实现节能脱盐和降本增效。将微咸矿井水的适度脱盐作为目标,将纳滤膜(NF)的筛分、道南效应作为理论基础,通过室内配水试验、现场小试、实验室表征等,系统性研究微咸矿井水的适度脱盐工艺及其关键运行参数。结果表明NF在允许部分一价离子通过的同时能够截留矿井水中高价态特征离子,其较为宽泛的脱盐率区间(37.4%~98.25%)相对反渗透技术在微咸矿井水适度净化方面更具优势;由于纳滤膜运行压力低、膜孔径大,相比反渗透膜的抗污染能力更强,纳滤适度脱盐工艺在无机污染物较重的微咸矿井水净化方面具有较大应用前景。
High-salinity mine water is widespread in mining areas in western China. In recent years, with the implementation of the westward coal strategy, the drought, water pollution, and ecological degradation in the region have become increasingly prominent, forcing more stringent policies and regulations on high-salinity mine water to re-use as water resources and meeting discharge standards, which has forced the continuous development of energy-saving and high-efficiency desalination technology for high-salinity mine water. In order to further improve the resource utilization level of high salinity mine water in western mining areas and reduce the cost of desalination, this research is based on extensive surveys of mine water quality and quantity, distribution status, and status quo of desalination technology, in response to the current mainstream technology of high salinity mine water desalination due to the use of non-selective desalination and the pure pursuit of high desalination rates, problems such as excessive desalination, process complexity, high energy consumption, membrane pollution, et al., a moderate desalination process is proposed for the graded and qualitative reuse of brackish mine water in the range of 1 000~3 000 mg/L in coal mine area. The core of the so-called moderate desalination is the selective removal of specific ions (such as Ca2+, Mg2+, SO2-4, et al.) in mine water, minimizing the cost of desalination, and achieving energy-saving desalination and cost reduction and efficiency enhancement under the premise of meeting relevant water quality requirements. This study takes the moderate desalination of brackish mine water as the goal, and takes the screening of nanofiltration(NF)membranes and the Donan effect as the theoretical basis. Through indoor water distribution experiments, field tests, laboratory characterization, etc., the systematic study of the brackish mine water moderate desalination process and its key operating parameters. The results show that NF membranes can intercept high-valence characteristic ions in mine water while allowing part of the monovalent ions to pass through. Its wider range of desalination rate(37.4%~98.25%) is more advantageous than reverse osmosis in the moderate purification of brackish mine water; due to the low operating pressure and large membrane pore size, NF have stronger anti-pollution ability than reverse osmosis. The moderate desalination process of NF has greater application prospects in the purification of brackish mine water with heavier inorganic pollutants.
high salinity; mine water; nanofiltration; moderate desalination; membrane fouling;mine water process
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会