实验模拟煤矸石自燃和不同因素对多环芳烃生成的影响

发布时间：2018-03-21 23:12

  本文选题：模拟煤矸石自燃　切入点：多环芳烃　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：煤矸石是煤矿生产的副产品，大量的煤矸石经过长时间的堆积发生自燃现象，产生有毒有害气体多环芳烃。多环芳烃的生成与煤矸石内部因素和外部自燃条件有密切的关系，为了研究不同变质程度煤层夹矸中多环芳烃的含量，以及煤矸石在自燃过程中外部条件对多环芳烃生成的影响，本文以山西太原西山马兰矿、屯兰矿、杜儿坪矿、西铭矿和山西晋城古书院矿的地下巷道煤矸石为研究对象，采用索氏提取和高效液相色谱（HPLC）等测试方法，讨论不同变质程度煤层夹矸中16种US EPA多环芳烃(PAHs)的含量特征；此外，在详细分析自然环境中煤矸石山自燃环境的基础上，于实验室固定床管式炉上模拟煤矸石自燃，分析PAHs的生成途径，探讨不同温度和通气量对PAHs生成的影响，，结果表明： （1）变质程度不同的煤层夹矸中含有的PAHs种类不同，但都含有萘和苯并[a]蒽，都不含有苯并[a]芘和茚并[1,2,3-cd]芘；随着变质程度的增强，PAHs的总含量和毒性都先增大，再减小，中高等变质程度的烟煤夹矸中PAHs的含量最多，毒性最强，无烟煤的煤层夹矸中PAHs的含量最少，毒性最弱。西铭矿、屯兰矿和杜儿坪矿煤矸石中的PAHs环数分布广，且高环PAHs所占比例相对较多。 （2）煤矸石自燃产生的PAHs总量和种类都大于未自燃前煤矸石中含有的PAHs，且自燃过程中PAHs的分布符合分馏效应，即模拟实验分析得的PAHs主要以LPAHs为主，自燃残余样品中PAHs以4环PAHs为主，同时检测到了5环和6环PAHs。煤矸石发生自燃后产生的PAHs毒性增强，且低温环境下自燃生成的PAHs的毒性大于高温环境。 （3）煤矸石自燃产生的PAHs以低环为主，在自燃过程中，较低温度下（≤450℃）氧化产生的PAHs大于较高温度（≥550℃）燃烧产生的PAHs，但高温环境燃烧产生的PAHs种类多，HPAHs所占的比例相对较大。 （4）煤矸石在较低空气流速下自燃，各温度阶段产生的PAHs变化相对比较平缓，在较高的空气流速下自燃，低温段的PAHs生成量远远大于高温段PAHs生成量，且各温度段的PAHs生成量变化相对比较剧烈。 （5）煤矸石发生自燃产生的萘（NaP）、菲（PhA）含量增多，低分子量多环芳烃占有绝对优势，且萘/菲基本都大于15，表明煤矸石自燃产生的PAHs来自于造岩源中大分子有机质分子键的断裂，但在高温环境下高温缩合或环化作用有所增强。
[Abstract]:Coal gangue is a by-product of coal mine production. After a long period of accumulation of coal gangue, a large number of coal gangue occur spontaneous combustion phenomenon, producing toxic and harmful gas polycyclic aromatic hydrocarbons. The generation of polycyclic aromatic hydrocarbons (PAHs) is closely related to the internal factors and external spontaneous combustion conditions of coal gangue. In order to study the content of polycyclic aromatic hydrocarbons (PAHs) in coal gangue with different metamorphic degrees and the influence of external conditions of coal gangue on the formation of PAHs in the process of spontaneous combustion of coal gangue, this paper deals with the formation of PAHs in Xishan Ma Lan Mine, Tunlan Mine and Duerping Mine in Taiyuan, Shanxi Province. Coal gangue in underground roadway of Ximing Mine and Guyuan Mine of Jincheng City, Shanxi Province was studied. The content characteristics of 16 kinds of US EPA polycyclic aromatic hydrocarbons (PAHs) in coal gangue with different metamorphism degree were discussed by Soxhlet extraction and HPLC (High performance liquid Chromatography). Based on the detailed analysis of the spontaneous combustion environment of coal gangue in the natural environment, this paper simulates the spontaneous combustion of coal gangue in a fixed bed tube furnace in laboratory, analyzes the way of PAHs formation, and discusses the influence of different temperature and ventilation on the formation of PAHs. The results show that:. (1) the coal bed gangue with different degree of metamorphism contains different kinds of PAHs, but all of them contain naphthalene and benzo [a] anthracene, neither of them contain benzo [a] pyrene or ninhydro [1o _ 2o _ 3-cd] pyrene. With the increase of metamorphism degree, the total content and toxicity of PAHs increase first, then decrease, The content of PAHs in gangue of bituminous coal of middle and higher metamorphism degree is the highest and the toxicity is the strongest, the content of PAHs in gangue of anthracite coal seam is the least and the toxicity is the weakest. The number of PAHs ring in coal gangue of Ximing, Tunlan and Duerping mines is widely distributed. And the proportion of high ring PAHs is relatively high. (2) the total amount and type of PAHs produced by spontaneous combustion of coal gangue is larger than that contained in coal gangue before spontaneous combustion, and the distribution of PAHs in the process of spontaneous combustion accords with fractionation effect, that is, the PAHs obtained by simulation experiment is mainly LPAHs. The main PAHs in the autoignition residual samples was 4-ring PAHs. At the same time, 5 rings and 6 rings of PAHs were detected. The toxicity of PAHs produced by spontaneous combustion of coal gangue was enhanced, and the toxicity of PAHs generated by spontaneous combustion at low temperature was higher than that in high temperature environment. 3) the PAHs produced by spontaneous combustion of coal gangue is mainly low ring, and in the process of spontaneous combustion, The PAHs produced by oxidation at lower temperature (鈮

本文编号：1645984