【作者】 孙彪；

【导师】 程卫民； 周刚；

【作者基本信息】 山东科技大学 ， 安全科学与工程， 2018， 博士

【摘要】 综采面产尘量约占矿井产尘总量的45%～80%,其中截割与移架是主要尘源。随着一次采全高综采工艺普遍推广且煤层开采强度日益增加,现有的煤尘污染特性相关理论与防治技术已不能够满足实际需求。为此本文采用理论分析、数值模拟、实验测试以及现场应用相结合的方法对综采面尘源局部雾化封闭控除尘技术进行研究。在综采面煤尘污染的相关研究中,滚筒截割时形成湍流风对煤尘逸散的影响常被忽略,从而导致研究结论不能够反映现场煤尘污染的实际情况。因此针对截割湍流风扰动前、后的综采面污染特性分别进行数值模拟并对比分析截割湍流风对煤尘逸散的扰动影响。截割湍流风具有极强的稳定性,且截割湍流风扰动下的偏移风流是致使煤尘侧向逸散并污染人行道区域的主要原因。在截割湍流风扰动下,呼吸带范围中的煤尘污染区域沿工作面通风反方向超前11.3 m且污染尺度延长约7.2 m,同时人行道中分布的峰值浓度增大约1倍。雾滴粒径与速度是影响雾滴捕尘效率与雾流封闭效果的主导因素,亦应该是选择喷雾降尘用喷嘴的主要依据。针对5类15种喷嘴进行雾化特性实验,不仅测定了喷嘴雾化角、有效射程以及流量等宏观雾化参数,而且测定了风流扰动下的雾滴粒径、速度等细观雾化参数并得到了雾滴粒径与速度在风流扰动下的分布规律。选择孔径为2.4 mm且含“X”导流芯的旋转式实心圆锥形广角喷嘴用于采煤机内喷雾;选择孔径为2.0 mm且含射流稳定器的直射式扇形喷嘴用于采煤机外喷雾;选择孔径为2.0 mm且含“X”导流芯的旋转式实心圆锥形广角喷嘴用于液压支架喷雾并对其布置方式进行了优化改进。基于截割湍流风扰动下的综采面煤尘污染特性与不同类型喷嘴的雾化特性,提出尘源局部雾化封闭控除尘技术,并研发了与之配套的文氏负压二次降尘装置与采煤机湿式除尘器。在6 MPa喷雾压力下,文氏负压二次降尘装置喷射雾滴的平均粒径约为50.59 μm,且所形成的负压流场对附近空气的卷吸流量约为11.57 m3/min。采煤机湿式除尘器的喷雾组包括10个喷嘴,在4 MPa喷雾水压下的雾流封闭尺寸能够完全覆盖滚筒;为了满足不同的现场应用条件,研制了电动机与液压马达驱动的除尘器,流量分别为190 m3/min与220 m3/min。为了考察综采面尘源局部雾化封闭控除尘技术的降尘效果,分别在枣庄矿业(集团)付村煤业有限公司1001,1007综采面以及蒋庄煤矿905综采面进行工程应用。结果表明,完整应用尘源局部雾化封闭控除尘技术能够有效缓解工作面中的煤尘污染状况:蒋庄煤矿905工作面各采样点处的平均降尘率约53.0%,移架工与前、后滚筒司机作业处的煤尘浓度分别为73.7、80.3、85.2 mg/m3;较工作面原有的喷雾降尘设施,降尘率平均提高约36.7%。更多还原

【Abstract】 The coal dust production in fully mechanized coal face accounts for about 45%～80%of the total production in mine,of which coal cutting and support movement processes are the main dust sources.With the popularization of fully-mechanized and full-seam nining method and the increasing mining intensity of coal seam,the existing theory and control technology of coal dust pollution is not enough to meet the actual demand.For this reason,theoretical analysis,numerical simulation,experiment and field application are combined to study local spray closure dedust technique and equipment in fully-mechanized mining face.In the research on coal dust pollution in fully-mechanized mining face,the effect of turbulent airflow from coal cutting on coal dust dispersion is often ignored,so that the research conclusion cannot reflect the actual situation of coal dust pollution on site.Therefore,the coal dust pollution characteristics in fully-mechanized mining face before and after turbulent airflow from coal cutting disturbance were simulated and compared to analyze the influence of turbulent airflow from coal cutting on coal dust dispersion.The turbulent airflow from coal cutting was fairly stable and the deviated migration airflow under turbulent airflow from coal cutting disturbance was the main reason for the lateral dispersion of coal dust and the pollution of footway area,Under turbulent airflow from coal cutting disturbance,the pollution region in the respiratory zone by coal dust noved forward by 11.3 m along the direction of ventilation along mining face,and the pollution region was prolonged by approximately 7.2 m and the peak coal dust concentration along the footway space was approximately doubled.The particle size and velocity of drop were the main factors influencing the efficiency of dust collection by drop and the closure effect of fog flow,and it should also be the main basis for selecting the nozzle for spray dedust.The atomization characteristic experiment of 15 nozzles in 5 categories were carried out,not only the macroscopic atomization parameters such as the atomization Angle,effective range and flow rate of the nozzles were measured,but also the microscopic atomization parameters such as the particle size and velocity of droplets were measured under the wind disturbance and the distribution law of the particle size and velocity of droplets under the wind disturbance was obtained.According to the experimental results,the hybrid solid-cone wide-angle nozzle with an X-shaped diversion core and a spray orifice diameter of 2.4 mm was selected for intenlal spray in shearer,the direct fan nozzle with a jet stabilizer and a spray orifice diameter of 2.0 mm was selected for external spray in shearer,and the hybrid solid-cone wide-angle nozzle with an X-shaped diversion core and a spray orifice diameter of 2.0 mm was selected for spray between hydraulic support and arrangement was optimized and improved.Based on the coal dust pollution characteristics under turbulent airflow from coal cutting disturbance and the atomization characteristics of different types of nozzles,the local spray closure dedust technique was put forward,and the corresponding Venturi negative-pressure secondary dedust device and shear scrubber were developed.Under the spray pressure of 6 MPa,the average diameter of spray droplets by Venturi negative-pressure secondary dedust device was 50.59 μm,and its negative pressure suction flow rate was 11.57 m3/min.The spray group in shear scrubber consists of 10 nozzles,and the spray coverage size under spray pressure of 4 MPa can completely cover the drum.In additon,in order to meet different field application conditions,shear scrubbers driven by motor and hydraulic motor was developed.Its flow rate was 190 m3/min and 220 m3/min,respectively.In order to investigate the dust removal effect of this dedust technique,the field applications were respectively carried out in the No.1001 and No.1007 fully-mechanized mining face of Fucun Coal Mine and the No.905 fully-mechanized mining face of Jiangzhuang Coal Mine owned by Shandong Energy Zaozhuang Mining Group Co.,Ltd.The results show that the complete application of local spray closure dedust technique can effectively alleviate the coal dust pollution in the fully-mechanized mining face:the average dust removal rate of each sampling point in the No.905 mining face of jiangzhuang coal mine was about 53.0%,among which the concentration of coal dust in the location where support moving worker,TG drum driver and MG drum driver operated were 73.7,80.3 and 85.2 mg/m3 respectively,and,the dust removal rate increased by 36.7%on average compared with the original spray dust removal facilities.更多还原