煤层气开采废水处理方法与技术研究

Research on Treatment Methods and Technologies of Coalbed Methane Mining Wastewater

煤层气作为一种清洁能源,其开采及利用有利于优化我国能源结构和缓解温室效应,但煤层气在开采过程中产生的废水若不经处理直接排放会对环境产生不利影响。本文将煤层气开采废水分为钻井废液、压裂返排液以及采出水3类,分别探讨了其水质和水量特征,并提出相应的处理工艺。钻井废液需混凝沉淀后,对产生的固液相根据实际需要分别进行处理;压裂返排液采用"混凝沉淀+A/O工艺"组合处理技术,处理后水中各类污染物的去除率预计可达80%以上;采出水经过"预氧化+混凝沉淀"去除水中大部分SS、Fe^(2+)及COD后,再通过"离子交换+除气+反渗透"工艺去除水中矿化度,悬浮物、COD以及矿化度等处理效率预计均可达到85%以上。

As a clean energy, the exploitation and utilization of coalbed methane is conducive to optimizing China’s energy structure and mitigating the greenhouse effect, but the waste water generated during the mining process of coalbed methane will adversely affect the environment if it is directly discharged without treatment. In this paper, the waste water from coalbed methane production is divided into drilling waste fluid, fracturing flow-back fluid and produced water. The water quality and quantity characteristics are discussed respectively, and corresponding treatment processes are proposed. The drilling waste liquid needs to be treated by the process of coagulation and sedimentation first, then the generated solid and liquid phases are separately treated according to actual needs. The fracturing return fluid adopts the "coagulation and sedimentation + A/O process" combined treatment technology, and the removal rate of various pollutants in the treated water is expected to reach more than 80%. The produced water is removed most of the SS, Fe^(2+) and COD by "pre-oxidation + coagulation and sedimentation" process first, then the degree of mineralization in the water is removed through the "ion exchange + degassing + reverse osmosis" process, and the treatment efficiency of suspended solids, COD and the degree of mineralization is expected to reach more than 85%.