【作者】 刘建国；

【导师】 金龙哲；

【作者基本信息】 北京科技大学 ， 安全科学与工程， 2021， 博士

【摘要】 沉积煤尘的二次飞扬对工人职业健康、矿区大气环境均造成严重影响。此外,对于井下沉积煤尘,其在冒顶片帮、冲击地压、煤与瓦斯突出等事故中,因冲击波作用可迅速扬起,达到煤尘爆炸浓度,对矿井安全生产与工人生命安全造成严重威胁。为此,本文旨在通过研究煤尘润湿性与爆炸性的多参数影响模型,分析煤尘润湿性与爆炸性影响机制,提出煤尘防爆抑尘材料研制方法,据此研究制备一种环保型复合防爆抑尘剂,并配套研发抑尘剂应用技术与装备,以期对井下沉积煤尘的二次飞扬与爆炸进行高效控制。为认识井下原始煤尘理化特性,表征分析了井下沉积煤尘的物理化学特性。采集了我国华北地区1 8个井下综采回风巷沉积煤尘,并对其润湿性、粒径分布、孔参数、爆炸参数、工业成分、元素含量、镜质组含量及碳官能团含量进行了表征,得到38个煤尘理化参数。将所得结果与文献中球磨煤尘的理化特性进行比较分析,结果显示:井下煤尘具有粒径小、孔结构发达的特征。18组煤尘粒径特征参数D10、D50、D90的平均值分别为5.64、26.49、65.83μm,呼吸性粉尘(P10)平均占比21%、最高占比42%;18组煤尘的平均BET比表面积为8.24 m2/g,平均孔体积为22.85 cm3/g,平均孔径为11.82 nm。较小的粒径分布、较发达的孔结构参数使得井下煤尘更加不易沉降。基于井下煤尘理化特性参数,利用多因素分析法构建了煤尘润湿性与爆炸性的多参数影响模型,探究了影响煤尘润湿性与爆炸性的核心因素,为研发防爆抑尘材料提供了理论基础。由皮尔斯相关系数分析得到煤尘润湿性受其多个理化参数共同影响,结合因子分析法与多元回归法构建了煤尘润湿性的多参数影响模型,得到煤尘孔参数和化学组分是影响其润湿性的核心因素,二者累积影响贡献值为53.75%。由皮尔斯相关系数分析得到影响煤尘爆炸性的理化参数较少,结合灰色关联度分析法与多元回归法构建了煤尘爆炸性的多参数影响模型,得到了影响煤尘爆炸强度的核心因素是固定碳含量、C含量与H含量,三者累积影响贡献值为79.40%。根据影响煤尘润湿性与爆炸性的核心因素,总结得到了提高煤尘润湿性、降低煤尘爆炸性的方法,即增加煤尘氧化程度、提高煤尘含水率、增加煤尘粒径、降低煤尘表面粗糙度;据此结合井下应用条件,提出复合防爆抑尘材料应具有润湿、粘结与吸水保湿三种功能,且其pH值应保持中性。研究了糖工业废料——糖蜜对煤尘的防爆抑制特性,结果表明糖蜜溶液具有弱酸性,其对煤尘具有一定润湿性与保湿性,具有显著粘结性与抑爆性。针对糖蜜溶液抑尘性能中的不足,先利用单因素变量法探究了其与润湿剂、吸湿剂及pH中和剂的协同配伍性,之后利用多因素正交实验法进一步探究了各组分对煤尘抗风蚀性与抑爆性的影响强度,确定了糖蜜基防爆抑尘剂的最佳组分配比。研究设计了糖蜜基防爆抑尘剂的工业制备工艺流程,并对其单位生产成本与应用成本进行了分析,得到其单位生产成本为2626.45元/吨(产量为500吨时),综采回风巷应用成本为0.16元/吨煤。基于糖蜜基防爆抑尘剂组分的环保性与无毒性,提出了在井上水塔直接配制抑尘剂的应用技术。为提高抑尘剂应用效果,基于井下压风送水管路自主研发了一套超声雾化喷洒装置与井下气水共用型过滤装置,该装置具有耗水量小、雾化性能强的特点,其可将抑尘剂溶液均匀喷洒在巷道表面,为抑尘剂溶液的高效应用提供了设备保障。最后,对糖蜜基防爆抑尘剂的抑尘性能进行了工业级测试,得到该抑尘剂对井下综采回风巷沉积煤尘具有显著抑制作用,喷洒后三天内抑尘率均高达62.86%,第四天后抑尘率开始下降,第七天时回到未喷洒前水平,即抑尘剂的有效抑尘周期为6—7天;利用20 L球形爆炸装置测试了防爆抑尘剂对三种煤尘的抑爆特性,得到其对次烟煤、烟煤和无烟煤煤尘最大爆炸压力的抑制率在20%-30%间,对三者爆炸指数的抑制率分别为57.45%、51.47%和76.98%。该研究成果对保障井下工人职业健康与安全、推动矿山绿色和谐发展提供了技术支撑。本论文包含图片100幅,表31个,参考文献264篇。更多还原

【Abstract】 In the process of coal mining,transportation and storage,secondary flying of deposited coal dust is a seriously problem,which has a had impact on the environment of mining area and the occupational health of workers.Under the shock wave,produced by the accidents of roof fall,impact ground pressure,coal and gas outburst in underground mines,the deposited coal dust can be rise rapidly and reachs the explosion concentration,which poses a serious threat to the life safety of underground workers.Therefore,in order to control the secondary flying and explosion of deposited coal dust in the underground,the purpose of this paper is to study the multi-parameter influence model of coal dust wettability and explosive,and to put forward the development method of explosion-proof dust suppression material,and to prepare an environmental-friendly explosion-proof dust suppressant.The physical and chemical characteristics of deposited coal dust(DCD)in underground mines were characterized and analyzed.18 DCD samples were obtained from 18 underground coal mines,locates in North China.Then,the physical and chemical properites of DCD were characterized,including the wettability,particle size distribution,pore parameters,explosion parameters,industrial composition,element content,vitrinite content and carbon functional group content.The results were compared with the characteristics of the coal dust prepared by ball mine in labs and reported in literature,and it was found that DCD dust has small particle size and well-developed pore structure.The average D10、D50、D90 of 18 DCD samples are 5.64,26.49,65.83 μm,respectively,and its average breathable dust percentage(P10)is 21%,the highest P10 reachs 42%.In addition,the average BET surface area of 10 DCD samples is 8.24 m2/g,its average pore volume is 22.85 cm3/g,its average pore size is 11.82 nm.Smaller particle size distribution and well-developed pore structure make underground coal dust more difficult to settle.Based on the physicochemical parameters of DCD,the multi-parameter influence models of wettability and explosive of DCD are constructed using multi-factor analysis method,and the core factors affecting wettability and explosive of DCD are explored.It provides a theoretical basis for the development of explosion-proof dust suppressant.From the result of Pierce correlation coefficient analysis,we found that the wettability of DCD was affected by many physicochemical parameters.Then,combining factor analysis method and multiple linear regression method,the multi-parameter influence model of DCD wettability was constructed.From this model,the core factors affecting the wettability were coal dust pore parameters and chemical components.On the contrary,for the coal dust explosion,Pierce correlation coefficient analysis shows that there are few physicochemical parameters affecting coal dust explosive.Combining grey correlation degree analysis and multiple linear regression method,a multi-parameter model of coal dust explosive was constructed.The core factors affecting coal dust explosion intensity are fixed carbon content,C content and H content.The cumulative contribution value of the three is 79.40%.According to the core factors affecting coal dust wettability and explosive,the methods of improving coal dust wettability and reducing coal dust explosive are summarized,that is,increasing coal dust oxidation degree,increasing coal dust moisture content,increasing coal dust particle size and reducing coal dust surface roughness.According to the application conditions,the composite explosion-proof dust suppression material should have three functions,i.e.,wetting,bonding and water absorption and moisturizing,and its pH value should be neutral.Explosion-proof inhibition of molasses,a waste from sugar industry,on DCD was studied.The results showed that molasses solution had weak acidity,moderate wettability and moisture retention to coal dust,and remarkable adhesion and explosion inhibition to coal dust.Considering the deficiency of dust suppression by molasses solution,the compound compatibility with wetting agent,hygroscopic agent and pH neutralizer was explored by single factor variable method.The influence strength of each component on wind erosion resistance and explosion inhibition of coal dust was further explored using multi-factor orthogonal experiment method,and the optimum composition distribution ratio of molasses-based compound explosion-proof dust suppressant was determined.The industrial preparation technology of molasses-based explosion-proof dust suppressant was studied and designed,and its unit production cost and application cost were calculated.The unit production cost was 2626.45 yuan/ton,and the application cost of fully mechanized mining return air roadway was 0.16 yuan.Based on the environmental protection and non-toxicity of molasses-based compound dust suppressant components,the application technology of direct preparation of dust suppressant in well water tower is put forward.In order to improve the application effect of dust suppressant,an ultrasonic atomization device is developed based on underground air supply pipeline.The device has the characteristics of low water consumption and strong atomization ability.It can spray liquid evenly on the surface of roadway,which provides equipment guarantee for the efficient application of dust suppressant solution.Finally,the dust suppression performance of molasses-based compound dust suppressant was tested at industrial level,and the dust suppression agent had significant inhibitory effect on coal dust deposited in fully mechanized coal mining return air roadway.The dust suppression rate was above 60%within three days after spraying,the dust suppression rate began to decrease after the fourth day,and returned to the pre-spraying level on the seventh day,that is,the effective dust suppression period of the dust suppressant was 6-7 days;A 20 L spherical explosive device was used to test the explosion suppression characteristics of three kinds of coal dust,and the maximum explosion pressure of secondary bituminous coal,bituminous coal and anthracite coal dust was between 20%and 30%,and the explosion index was 57.45%,51.47%and 76.98%,respectively.This research provides a technical support for ensuring the occupational health and safety of underground workers and promoting the green and harmonious development of mines.The thesis contains 100 pictures,31 tables and 264 references.更多还原