地下煤火典型污染物富集特性与迁移规律研究

Underground coal fire is one disaster associated with coal mining activities around the world. It not only burns up lots of coal resources, but also brings a serious environmental problem to local community. At a certain extent, it also brings a contribution to the global climate change. How to quantify the coal fire's impact on environment is the core of research in coal fire field. This project is focused on the research of coal fire's typical pollutants' accumulation and its migration regularity within different environmental media, such as the soil and the air environment. For the research of typical pollutants' accumulation, harmful products from coal combustion within experimental stove will be studied by both the experimental facilities and the theoretical method for determining the kinds of pollutants from coal fire at first. Then, considering the evolution of intensity of coal combustion within coal fire, the process of the production and accumulation of typical pollutants coupling with the intensity evolution of coal combustion within coal fire will be studied. Factors, such as the coal quality, the climate change, and the geological conditions as well as the properties of coal fire control volume will be included in this coupling study. From this part of research, based on methods of the theoretical and the laboratory experiments as well as the field surveying, a relevant internal relationship between the coal fire's typical pollutants' accumulation and the coal fire's thermal dynamic intensity evolution will be established which can be used to reveal the mechanism of coal fire's thermal effect on typical pollutants' accumulation. For the research of typical pollutants' migration within the soil and the air environment, the physical transportation of typical pollutants within fire zone and its affected areas, and the chemical transfer of typical pollutants will be studied in this project. Factors, such as the soil properties, the meteorological parameters, and the geological conditions as well as the subsurface hydrological process, which plays an important role for pollutants to move within environmental media, also will be included in this study. From this part of research, a multi-parameters coupling model considering above factors' impact will be established to describe the pollutants movement within the soil and the air environment. Results from this research project will provide a solid basis for revealing the mechanism of coal fire's impact on environment and a theoretical method of quantifying coal fire's impact on environment as well as a basis for future recovery of eco-environment system for coal fire. At a certain point, it also provides a necessary foundation for the development of coal fire science.

针对新疆地区地下煤火开展其典型污染物富集特性与迁移规律的研究，主要研究内容：①.地下煤火典型污染物富集特性研究：通过理论分析、实验室测试、现场监测，研究地下煤火典型污染物产出、富集特性与煤火热效应强度演化规律的耦合过程，定量筛分煤火典型污染物类别，建立地下煤火污染源清单，构建其富集特性与煤火热效应强度的关联模型，建立煤火热效应典型污染物富集-污染模型，揭示煤火热效应对火区环境介质典型污染物富集过程的作用机理；②.地下煤火典型污染物迁移规律研究：通过理论分析、实验测试、现场观测与数值模拟，研究煤火热效应典型污染物在火区及区域环境介质中的物理迁移与化学转化过程；研究土壤、气象、区域地质及水文因子对煤火典型污染物迁移过程的影响，构建基于多因子参数分析的煤火典型污染物迁移耦合模型。通过本课题研究，可有效揭示地下煤火对区域环境的作用机理，为科学定量评价煤火环境影响及火区生态修复与重建提供理论基础。

1.项目背景.地下煤火是伴生煤炭资源开采的一种灾害，其不仅燃烧损失大量煤炭资源，还对区域生态环境造成严重破坏。本项目针对新疆地区煤火，在前期已开展的煤火燃烧系统热动力特性建模研究基础上，开展新疆地区煤火热效应对区域生态环境的影响-即煤火典型污染物富集特性与迁移规律，旨在为科学评价煤火环境影响、有效应对和治理新疆地区煤火衍生环境问题提供基础。.2.主要研究内容.1）煤火典型污染物产出、富集特性研究：主要研究地下煤火燃烧煤层煤质、燃烧强度与典型污染物产出规律的关联特性及其演化规律；研究煤火热效应典型污染物分类特征，建立地下煤火环境影响污染源清单；构建煤火热动力演化的典型污染物产出、富集模型。.2）煤火典型污染物迁移规律研究：主要研究地下煤火典型污染物在区域土壤环境、大气环境中的迁移规律及气象、土壤、区域地质与水文因子对其迁移过程的影响。.3.重要结果.1）通过程序氧化升温实验、热重分析、化学热力学平衡分析方法（FACTSage）模拟研究了煤火典型污染物产出特征，结果表明：CO2、CO依然是煤火燃烧主要气态产物。火区现场监测数据反应同样规律。初步建立了煤火污染源清单。.2）通过火区土壤采样分析，结合数值与土柱淋滤实验，研究了火区土壤重金属分布特征与迁移规律，结果表明：煤火热效应改变了火区土壤理化性质；火区土壤有机质含量对土壤重金属吸附过程具有重要影响作用；土壤有机质含量高低对土壤重金属迁移具有重要影响；除火区土壤温度外，火区区域气象因子、地形因子、土壤因子对火区土壤重金属分布与迁移过程具有重要影响，其相互之间具有耦合效应。.4.关键数据.1）采集大泉湖火区土壤样，开展了火区土壤重金属吸附、解吸特性试验，分析了土壤样重金属含量，开展了典型重金属淋滤实验，开展了火区土壤典型重金属迁移的数值模拟研究。.3）在大泉湖火区建立了火区气象监测站，开展了火区气象参数在线连续监测。.5.科学意义.初次系统地开展了煤火热效应导致火区土壤理化性质、重金属分布与迁移规律的研究，深入了煤火的理论认知；建立了火区气象监测站开展气象参数长期监测，监测数据可为火区烟气排放、扩散规律及治理后火区生态修复研究提供数据基础。