煤炭在满足全球能源需求方面发挥着重要作用,是我国一次能源的重要组成部分,随着我国经济转向高质量发展阶段,生态文明建设进入推动减污降碳协同增效、促进经济社会发展全面绿色转型、实现生态环境质量改善由量变到质变的关键时期,煤炭清洁高效利用成为国家工作重点。煤气化废水是煤制天然气过程中低温/中温气化装置产生的主要废物流,主要特征为高酚、高氨、含多种有毒难降解的有机和无机污染物,是一种典型的高浓度难生物降解工业废水,对环境负面影响极大。我国水资源和煤炭资源的逆向分布,废水处理与回用既是对节能减排政策的响应,也是优化水资源和煤炭资源配置的重要措施。目前,已有多种技术被应用于煤气化废水治理,在平衡处理效果和经济性等因素后基本达成共识,即采用物化+生化、厌氧+好氧的处理工艺。治理技术路线主要由预处理、生物处理和深度处理3部分组成,治理后的废水可满足国家废水排放标准。介绍了煤气化废水的预处理、生物处理和深度处理相关技术及处理效果和工艺的优缺点,分析了生产中存在的技术瓶颈,并介绍了其他新型处理工艺,如冷冻浓缩法、水汽集成式近零排放法、微生物燃料电池法等。目前,多数关于煤气化废水处理的研究仍局限于特定方法,忽视了处理过程的综合工程系统,应关注对物化、高级氧化与生物处理技术的优化集成,提高处理效率并降低建设和运行成本,同时加强对新工艺的开发,将煤气化废水的处理过程与煤气化工艺过程更好结合,提升水再利用的潜力、减少能量消耗和污染物产生,最后需关注煤气化废水的资源化利用和其潜在的资源价值,开发其利用方式,真正将气化废水的资源潜力挖掘出来,实现变废为宝。

Coal plays an important role in meeting global energy demand, and is also an important part of China′s primary energy structure.With the transformation of China′s economy to a high-quality development stage, the construction of ecological civilization has entereda critical period to promote the coordinated development of pollution reduction, carbon reduction and efficiency improvement, promotethe comprehensive green transformation of economic and social development, and realize the improvement of the quality of the ecologicalenvironment. Clean and efficient use of coal has become the focus of national work. Coal gasification wastewater is the main wastestream generated by the low-temperature/ medium-temperature gasification units. It is characterized by high content of phenol and ammonia, and contains various toxic and difficult - to - degrade organic and inorganic pollutants. It is a typical industrial wastewater withhigh concentration and biological resistance, which has obvious negative impacts on the environment. The reverse distribution of water resources and coal resources in China makes wastewater treatment and recycling not only a response to energy conservation and emission reduction policies but also an important measure for optimizing the allocation of water and coal resources. At present, various technologieshave been applied to the treatment of coal gasification wastewater. After balancing factors such as treatment effect and economy, a consensus has been reached that the physical-chemical and biological treatment processes combining anaerobic and aerobic processes should beadopted. The technical route of this treatment is mainly composed of pretreatment, biological treatment and advanced treatment, and thetreated wastewater can meet national sewage discharge standards. This article introduces the relevant technologies, treatment effectiveness,and advantages and disadvantages of the pretreatment, biological treatment, and advanced treatment of coal gasification wastewater. It analyzes the technical bottlenecks in production, and introduces other new treatment processes, such as freezing concentration, steam-waterintegration with near zero emission and microbial fuel cell methods. From the analysis of relevant literature, most of the researchon coal gasification wastewater treatment still focuses on specific methods, while ignoring the comprehensive engineering system of thetreatment process. It is necessary to focus on optimizing the integration of physical-chemical, advanced oxidation, and biological treatmenttechnologies, improving treatment efficiency, reducing construction and operation costs, and strengthening the development of new processes. Better combination of the coal gasification wastewater treatment process and gasification process can improve the potential for water reuse and reduce energy consumption and pollutant production. Finally, it is important to pay attention to the resource utilization of coal gasification wastewater, explore its potential resource value, develop utilization methods, and truly tap into the resource potential of gasification wastewater, thus turning waste into treasure.

0 引言

1 煤气化废水特征

2 预处理

   2.1 除油除尘

   2.2 酚氨回收

3 生化处理工艺

   3.1 厌氧氧化法

   3.2 好氧氧化法

   3.3 耦合生物处理

4 深度处理工艺

   4.1 物理化学法

   4.2 高级氧化法

   4.3 深度处理耦合工艺

5 其他处理工艺

6 CGW处理发展方向