Key technologies and equipment for green short process of coal mine drainage resource utilization
HE Xuwen;WANG Shaozhou;ZHANG Xuewei;JI Xiaoqing
煤炭是我国重要的工业原料,与我国经济发展关系密切。煤炭开采过程中会产生大量矿井水,是重要的非常规水资源,需妥善处理。然而现有矿井水处理技术普遍存在占地大、流程长、需加药、运行维护复杂和出水水质不稳定等问题,为缩短处理流程、提高处理效率和保证出水水质,亟需研发新的关键技术与装备。采用聚瓷膜直滤技术处理矿井水,通过对膜通量、膜比通量、运行压力和循环流量等条件的对比分析,确定最佳运行参数为:运行压力0.2 MPa,循环流量18 m3/h,处理过程无需加药,出水悬浮物质量浓度稳定 < 1 mg/L,浊度稳定 < 1 NTU。采用广泛应用的膜堵塞模型来探讨膜污染机制,膜污染分析结果表明,膜污堵主要以滤饼层污堵为主,并伴随中间污堵,具体表现为膜的表面污染和膜孔的堵塞。通过水力反洗及时清除膜表面污染,最佳反洗时间为60 s,通量恢复率为85.12%;通过定时化学清洗清除膜孔污堵,用复配制剂清洗3 h,通量恢复率可达95%以上。工程案例表明,聚瓷膜直滤可直接取代“混凝沉淀−过滤−超滤”(一代三),且已连续稳定运行2 a,满足设计产水量要求,系统回收率均在90%以上,处理后水质达到GB 3838—2002地表水环境质量III类24种标准限值要求,且自动化程度高,可无人值守,实现了矿井水资源化利用绿色短流程、节能高效和智能化新要求,可为该技术大规模推广应用提供技术参考。
Coal is an important industrial raw material in China, closely related to its economic development. During coal mining, a large amount of coal mine drainage is generated, which is an important unconventional water resource that needs to be properly treated. However, the existing coal mine drainage treatment technology generally has problems such as large land occupation, long process, dosing requirement, complex operation and maintenance, and unstable effluent quality. In order to shorten the treatment process, improve treatment efficiency, and ensure effluent quality, it is urgent to develop new key technologies and equipment. This study adopts the PolyCera membrane direct filtration technology to treat coal mine drainage. By comparing and analyzing the conditions of membrane flux, membrane specific flux, operating pressure, and circulating flow rate, the optimal operating parameters are determined as follows: operating pressure of 0.2 MPa, circulating flow rate of 18m3/ h. The treatment process does not require dosing, and the stable concentration of suspended solids in the effluent is less than 1 mg/L, and the stable turbidity is less than 1 NTU. Using the most widely used membrane fouling model to explore the mechanism of membrane fouling, the analysis results of membrane fouling indicate that membrane fouling is mainly caused by cake layer fouling, accompanied by intermediate fouling, specifically manifested as surface fouling of the membrane and blockage of membrane pores. The membrane surface pollution is timely removed through hydraulic backwashing, with an optimal backwashing time of 60 s and a flux recovery rate of 85.12%. By regularly cleaning the membrane pores with chemical cleaning, and with a composite formulation for 3 hours cleaning, the flux recovery rate can reach over 95%. Engineering cases have shown that the PolyCera membrane direct filtration can directly replace the "coagulating sedimentation -filtration-ultrafiltration" (one process replaces three), and has been continuously and stably operating for 2 years, meeting the design water production requirements. The system recovery rate is above 90%, and the water quality meets the requirements of 24 standard limits for Class III surface water environmental quality in GB 3838—2002. Also, it has a high degree of automation and can be unmanned, achieving some new requirements of resource utilization of coal mine drainage, green and short process, energy conservation, efficiency, and intelligence. It can provide a technical reference for the large-scale promotion and application of the technology.
coal mine drainage;PolyCera membrane;direct filtration;membrane fouling;resource utilization
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