Jiangsu Key Laboratory of Fire Safety in Urban Underground Space, China University of Mining and Technology, Xuzhou 221116, China.
Jiangsu Key Laboratory of Fire Safety in Urban Underground Space, China University of Mining and Technology, Xuzhou 221116, China; Key Laboratory of Gas and Fire Control for Coal Mines, China University of Mining and Technology, Ministry of Education, Xuzhou 221116, China; School of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Sci Total Environ. 2021 Jul 10;777:146080. doi: 10.1016/j.scitotenv.2021.146080. Epub 2021 Feb 26.
Long-term spontaneous combustion of coal has caused serious ecological and environmental problems. Only in recent years has it received growing popularity to undertake relevant researches. In order to study the impact of combustion by-products on atmosphere in the Sandaoba fire field, Xinjiang, a region-scale field survey was firstly conducted to investigate the gaseous-solid emissions in separated fire sections. The evaluation method and model have been proposed to describe the underground combustion and the related air pollution. Every year, the total estimates of the gaseous emission are approximately 4030 t of CO, 113.6 t of SO and 57.3 t of CO. The emission pollution varies considerably from regions, and is substantially attenuated with the advancement of fire control. Principal component analysis (PCA) refines the thermophysical parameters into three attributions: the intrinsic thermophysical property, atmospheric dynamics, and combustion degree. PCA score distribution shows that thermophysical parameter is dominated by the combustion condition at severely polluted areas. Factor Analysis is used to extract four contaminant indicators, which suggests the local air suffers sulfur oxides pollution the most. The air quality index of the eight study sections calculated are all below 60, ranging from 24 to 58. It indicates that coal fire air pollution is in the medium-to-severe stage. By Canonical Correlation Analysis, it is noted that thermophysical indicator performs outstanding explanatory for contaminant variates. On the whole, the higher the level of thermophysical properties in the fire area, the greater the intensity of pollutant emission. Underground coalfield fire is dominated by smoldering, and the overall combustion efficiency is lower than 0.8 which generally declines as the excess air coefficient increasing.
煤的长期自然燃烧已造成严重的生态和环境问题。只是近年来，它才越来越受到关注，相关研究也越来越多。为了研究燃烧产物对新疆三垅沙火区大气的影响，首次进行了区域尺度的野外调查，以研究分离火区的气态-固态排放物。提出了评价方法和模型来描述地下燃烧和相关的空气污染。每年，气态排放的总量估计约为 4030 吨 CO、113.6 吨 SO 和 57.3 吨 CO。排放污染因地区而异，随着火灾控制的推进而大幅减弱。主成分分析（PCA）将热物理参数细化为三个属性：固有热物理性质、大气动力学和燃烧程度。PCA 得分分布表明，热物理参数主要由严重污染地区的燃烧条件决定。因子分析提取了四个污染物指标，表明当地空气受到硫氧化物污染最严重。计算的八个研究区的空气质量指数均低于 60，范围从 24 到 58。这表明煤火空气污染处于中重度阶段。通过典型相关分析，注意到热物理指标对污染物变量具有出色的解释能力。总的来说，火区热物理特性水平越高，污染物排放强度越大。地下煤层火灾以闷烧为主，整体燃烧效率低于 0.8，随着过剩空气系数的增加而普遍下降。
