综放采空区瓦斯与煤自燃多场耦合模拟研究
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摘要
为了分析瓦斯与煤自燃多场耦合致灾特性,结合瓦斯抽采引起的采空区混合气体流动、气体组分渗流与采空区渗透率变化、固气两相热量传输等多物理过程,建立了基于综放采空区高位钻孔瓦斯抽采的热-流-化多场耦合数学模型,采用COMSOL软件模拟了综放采空区高位钻孔抽采瓦斯诱导煤自燃过程,阐明了瓦斯与煤自燃多场耦合致灾机理,得到了寸草塔二矿31102综放采空区氧化带范围与高温范围,并探讨了抽采强度对综放采空区氧浓度场与温度场的影响。研究结果表明:高位钻孔抽采瓦斯有效地降低了回风巷瓦斯浓度,保证了31102综放工作面安全高效回采。增大综放采空区高位钻孔抽采瓦斯强度不能保证煤自燃安全性,二者存在矛盾,在得到高效抽采瓦斯的同时,会造成进风侧氧化带宽度增加,采空区氧化带边界向深处蔓延,扩大煤自燃高温区域,漏风携氧充分的参与煤氧复合反应,采空区最高温度逐渐上升,煤自燃风险增大。
Combined with the multi-physical processes such as mixed gas flow in the goaf caused by gas drainage,gas component seepage and permeability change in the goaf,and solid-gas two-phase heat transfer,a thermal-fluid-chemical multi-field coupling mathematical model based on the high-level borehole gas drainage in the goaf of fully mechanized caving face was established. The COMSOL software was used to simulate the spontaneous combustion process of coal induced by gas with highlevel borehole drainage in the goaf of fully mechanized caving face,and the disaster-causing mechanism of multi-field coupling of gas and coal spontaneous combustion was clarified. The oxidation zone range and high temperature range of 31102 goaf of fully mechanized caving face in Cuncaota No. 2 Mine were obtained,and the influence of drainage intensity on oxygen concentration field and temperature field in goaf of fully mechanized caving face was discussed. The results showed that the high-level borehole gas drainage effectively reduced the gas concentration in the return air passage,which ensured the safe and efficient recovery of 31102 fully mechanized caving face. Increasing the intensity of high-level borehole gas drainage in the goaf of fully mechanized caving face could not guarantee the safety of coal spontaneous combustion,and there existed the contradiction between them. When getting the high-efficiency gas drainage,the width of oxidation zone on the inlet side would increase,and the boundary of oxidation zone in the goaf would spread deeper,so the high temperature area of coal spontaneous combustion would expand. Then the air leakage with oxygen would fully participate in the coal-oxygen complex reaction,and the highest temperature of goaf would gradually rise,so the risk of coal spontaneous combustion would increase.
Combined with the multi-physical processes such as mixed gas flow in the goaf caused by gas drainage,gas component seepage and permeability change in the goaf,and solid-gas two-phase heat transfer,a thermal-fluid-chemical multi-field coupling mathematical model based on the high-level borehole gas drainage in the goaf of fully mechanized caving face was established. The COMSOL software was used to simulate the spontaneous combustion process of coal induced by gas with highlevel borehole drainage in the goaf of fully mechanized caving face,and the disaster-causing mechanism of multi-field coupling of gas and coal spontaneous combustion was clarified. The oxidation zone range and high temperature range of 31102 goaf of fully mechanized caving face in Cuncaota No. 2 Mine were obtained,and the influence of drainage intensity on oxygen concentration field and temperature field in goaf of fully mechanized caving face was discussed. The results showed that the high-level borehole gas drainage effectively reduced the gas concentration in the return air passage,which ensured the safe and efficient recovery of 31102 fully mechanized caving face. Increasing the intensity of high-level borehole gas drainage in the goaf of fully mechanized caving face could not guarantee the safety of coal spontaneous combustion,and there existed the contradiction between them. When getting the high-efficiency gas drainage,the width of oxidation zone on the inlet side would increase,and the boundary of oxidation zone in the goaf would spread deeper,so the high temperature area of coal spontaneous combustion would expand. Then the air leakage with oxygen would fully participate in the coal-oxygen complex reaction,and the highest temperature of goaf would gradually rise,so the risk of coal spontaneous combustion would increase.
引文
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[14]肖鹏,李树刚,林海飞,等.基于物理相似模拟实验的覆岩采动裂隙演化规律研究[J].中国安全生产科学技术,2014,10(4):18-23.XIAO Peng,LI Shugang,LIN Haifei,et al. Research on evolution law of overburden mining fissure based on physical similarity simulation experiment[J]. Journal of Safety Science and Technology,2014,10(4):18-23.
[15]王青元,杨天鸿,陈仕阔,等.高位顺层钻孔瓦斯抽放数值模拟[J].东北大学学报(自然科学版),2012,33(1):116-119.WANG Qingyuan,YANG Tianhong,CHEN Shikuo,et al. Numerical simulation of gas extraction in high-level bedding boreholes[J].Journal of Northeastern University(Natural Science),2012,33(1):116-119.
[16]许家林,钱鸣高.岩层采动裂隙分布在绿色开采中的应用[J].中国矿业大学学报,2004,33(2):17-20,25.XU Jialin,QIAN Minggao. Application of mining fissure distribution in green mining[J]. Journal of China University of Mining&Technology,2004,33(2):17-20,25.
[17]程卫民,张孝强,王刚,等.综放采空区瓦斯与遗煤自燃耦合灾害危险区域重建技术[J].煤炭学报,2016,41(3):662-671.CHENG Weimin,ZHANG Xiaoqiang,WANG Gang,et al. Reconstruction technology of gas-fired and residual coal spontaneous combustion coupled danger zone in fully mechanized caving face[J].Journal of China Coal Society,2016,41(3):662-671.
[18]秦波涛,张雷林,王德明,等.采空区煤自燃引爆瓦斯的机理及控制技术[J].煤炭学报,2009,34(12):1655-1659.QIN Botao,ZHANG Leilin,WANG Deming,et al. Mechanism and control technology of coal spontaneous combustion detonation in goaf[J]. Journal of China Coal Society,2009,34(12):1655-1659.
[19]郝健池.矿井可燃性气体爆炸特性研究[J].煤炭技术,2015,34(10):152-154.HAO Jianchi. Study on explosion characteristics of combustible gas in mine[J]. Coal Technology,2015,34(10):152-154.
[2]周福宝.瓦斯与煤自燃共存研究(I):致灾机理[J].煤炭学报,2012,37(5):843-849.ZHOU Fubao. Coexistence of gas and coal spontaneous combustion(I):Mechanism of disaster[J]. Journal of China Coal Society,2012,37(5):843-849.
[3]褚廷湘,余明高,杨胜强,等.瓦斯抽采对U+Ⅱ型近距离煤层自燃的耦合关系[J].煤炭学报,2010,35(12):2082-2087.CHU Tingxiang,YU Minggao,YANG Shengqiang,et al. Coupling relationship between gas extraction and spontaneous combustion of U+II type close coal seam[J]. Journal of China Coal Society,2010,35(12):2082-2087.
[4]张春,题正义,李宗翔.综放采空区遗煤自燃的三维数值模拟研究[J].中国安全科学学报,2013,23(5):15-21.ZHANG Chun,TI Zhengyi,LI Zongxiang. Three-dimensional numerical simulation of spontaneous combustion of residual coal in goaf in fully mechanized caving face[J]. China Safety Science Journal,2013,23(5):15-21.
[5]李宗翔.高瓦斯易自燃采空区瓦斯与自燃耦合研究[D].阜新:辽宁工程技术大学,2007.
[6]李宗翔,贾化成,毕强,等.放顶煤采空区瓦斯源强度与自燃的关联性[J].煤炭学报,2012,37(S1):120-125.LI Zongxiang,JIA Huacheng,BI Qiang,et al. Correlation between gas source intensity and spontaneous combustion in top coal caving area[J]. Journal of China Coal Society,2012,37(S1):120-125.
[7]邸帅,王继仁,郝朝瑜,等.多场耦合作用下瓦斯与煤自燃协同预防数值模拟[J].安全与环境学报,2018,18(2):497-503.DI Shuai,WANG Jiren,HAO Chaoyu,et al. Numerical simulation of coordinated prevention of gas and coal spontaneous combustion under multi-field coupling[J]. Journal of Safety and Environment,2018,18(2):497-503.
[8]赵奇,王雪峰,黄戈,等.采空区瓦斯抽采技术与浮煤自燃耦合治理研究[J].煤炭科学技术,2017,45(10):111-116.ZHAO Qi,WANG Xuefeng,HUANG Ge,et al. Study on the coupling treatment of gas extraction technology and floating coal spontaneous combustion in goaf[J]. Coal Science and Technology,2017,45(10):111-116.
[9]肖峻峰,樊世星,卢平,等.高瓦斯易自燃工作面高抽巷瓦斯抽采与采空区遗煤自燃相互影响研究[J].中国安全生产科学技术,2016,12(2):20-26.XIAO Junfeng,FAN Shixing,LU Ping,et al. Study on the interaction between gas extraction in high extraction roadway and high spontaneous combustion of goaf in high gassy spontaneous combustion working face[J]. Journal of Safety Science and Technology,2016,12(2):20-26.
[10]马东民,李来新,李小平,等.大佛寺井田4号煤CH4与CO2吸附解吸实验比较[J].煤炭学报,2014,39(9):1938-1944.MA Dongmin,LI Laixin,LI Xiaoping,et al. Comparison of adsorption and desorption of CH4and CO2in No. 4 coal of Dafosi mine field[J]. Journal of China Coal Society,2014,39(9):1938-1944.
[11]施永威,王宗林,梁冰,等.本煤层顺层预抽瓦斯钻孔间距数值模拟研究[J].中国安全生产科学技术,2017,13(5):21-27.SHI Yongwei,WANG Zonglin,LIANG Bing,et al. Numerical simulation of the pre-extracted gas drilling distance in the coal seam[J]. Journal of Safety Science and Technology,2017,13(5):21-27.
[12]贾廷贵,娄和壮,闻文.不同配风条件下“Y”型通风采场瓦斯涌出规律[J].辽宁工程技术大学学报(自然科学版),2019,38(1):14-18.JIA Tinggui,LOU Hezhuang,WEN Wen. The law of gas emission in“Y”type ventilation stope under different air distribution conditions[J]. Journal of Liaoning Technical University(Natural Science Edition),2019,38(1):14-18.
[13]夏同强.瓦斯与煤自燃多场耦合致灾机理研究[D].徐州:中国矿业大学,2015.
[14]肖鹏,李树刚,林海飞,等.基于物理相似模拟实验的覆岩采动裂隙演化规律研究[J].中国安全生产科学技术,2014,10(4):18-23.XIAO Peng,LI Shugang,LIN Haifei,et al. Research on evolution law of overburden mining fissure based on physical similarity simulation experiment[J]. Journal of Safety Science and Technology,2014,10(4):18-23.
[15]王青元,杨天鸿,陈仕阔,等.高位顺层钻孔瓦斯抽放数值模拟[J].东北大学学报(自然科学版),2012,33(1):116-119.WANG Qingyuan,YANG Tianhong,CHEN Shikuo,et al. Numerical simulation of gas extraction in high-level bedding boreholes[J].Journal of Northeastern University(Natural Science),2012,33(1):116-119.
[16]许家林,钱鸣高.岩层采动裂隙分布在绿色开采中的应用[J].中国矿业大学学报,2004,33(2):17-20,25.XU Jialin,QIAN Minggao. Application of mining fissure distribution in green mining[J]. Journal of China University of Mining&Technology,2004,33(2):17-20,25.
[17]程卫民,张孝强,王刚,等.综放采空区瓦斯与遗煤自燃耦合灾害危险区域重建技术[J].煤炭学报,2016,41(3):662-671.CHENG Weimin,ZHANG Xiaoqiang,WANG Gang,et al. Reconstruction technology of gas-fired and residual coal spontaneous combustion coupled danger zone in fully mechanized caving face[J].Journal of China Coal Society,2016,41(3):662-671.
[18]秦波涛,张雷林,王德明,等.采空区煤自燃引爆瓦斯的机理及控制技术[J].煤炭学报,2009,34(12):1655-1659.QIN Botao,ZHANG Leilin,WANG Deming,et al. Mechanism and control technology of coal spontaneous combustion detonation in goaf[J]. Journal of China Coal Society,2009,34(12):1655-1659.
[19]郝健池.矿井可燃性气体爆炸特性研究[J].煤炭技术,2015,34(10):152-154.HAO Jianchi. Study on explosion characteristics of combustible gas in mine[J]. Coal Technology,2015,34(10):152-154.