不同变质程度煤导热系数试验分析
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摘要
煤自燃不仅严重威胁着矿井的安全生产,甚至会引发火灾事故造成资源浪费和人员伤亡。煤岩体之间的热传导是引起煤自燃的关键因素之一,因此对煤岩体的传热能力开展研究是很有必要的。煤的导热系数是判定煤岩热传导能力的重要参数。在本研究中,为了分析不同变质程度煤的导热系数,探究温度和含水量对煤样导热系数的影响,在不同环境温度和含水量情况下分别测试了焦煤、长焰煤、褐煤、无烟煤和不黏煤这5种不同变质程度的煤样。采用LFA457型激光导热仪对这几种不同变质程度煤样的导热系数进行了测定。此外,应用Pearson相关系数法分析了不同煤质指标对煤样导热系数的影响规律。试验结果表明:煤样的导热系数与其变质程度呈负相关,即随变质程度的增加而逐渐减小;当温度为-50～10℃时,煤样的导热系数随着温度升高而显著升高;在10～50℃时,煤样的导热系数呈现出先缓慢增大最后趋于平稳的趋势;煤样的变质程度越低,其含水量对导热系数的影响越大; Pearson相关系数法的分析结果表明煤质指标对煤样导热系数影响的重要程度依次为灰分、固定碳、挥发分和水分。该试验研究有助于了解不同变质程度煤导热系数的影响因素及变化规律,并可进一步为煤火灾害的防治工作提供一定的理论基础。
Coal spontaneous combustion is a serious threat in safe production of coal,which could result in a coal fire,causing waste of resources and serious injuries and fatalities.Heat transfer between coal and rock is one of the key factors causing coal spontaneous combustion.Thus,research on heat transfer between coal and rock is essential to reduce coal spontaneous combustion.The thermal conductivity of coal is a major parameter for determining the thermal ability of coal.In this study,we analyze the thermal conductivity of different ranks of coal and investigate the effect of temperature and moisture content on thermal conductivity.Five coal samples of different ranks,namely coking coal,long flame coal,lignite,anthracite,and non-stick coal,were tested respectively under different ambient temperatures and moisture contents.Meanwhile,the thermal conductivity of these five coal samples was measured by the LFA457 laser thermal conductivity meter.In addition,the Pearson correlation coefficient methodwas applied to explore the effect of different coal compositions on thermal conductivity.The results indicate that the thermal conductivity of coal samples is negatively correlated with thecoal rank.In another word,lower thermal conductivity is associated with higher coal rank.When temperature is-50～10 ℃,the thermal conductivity of coal increases swiftly with the increase of temperature.When temperature is10～50 ℃,the thermal conductivity of coal increases slowly and then tends to be stable.A lower degree of coal maturity indicates a greater effect of moisture content on thermal conductivity.It is also found that ash has the most significant influence on thermal conductivity of coal,then followed by fixed carbon,volatile matter,and moisture.This experimental study provides an understanding of influence factors and variation laws of thermal conductivity of different ranks of coal,and further provides a theoretical basis for the prevention and control of coal fire disasters.
Coal spontaneous combustion is a serious threat in safe production of coal,which could result in a coal fire,causing waste of resources and serious injuries and fatalities.Heat transfer between coal and rock is one of the key factors causing coal spontaneous combustion.Thus,research on heat transfer between coal and rock is essential to reduce coal spontaneous combustion.The thermal conductivity of coal is a major parameter for determining the thermal ability of coal.In this study,we analyze the thermal conductivity of different ranks of coal and investigate the effect of temperature and moisture content on thermal conductivity.Five coal samples of different ranks,namely coking coal,long flame coal,lignite,anthracite,and non-stick coal,were tested respectively under different ambient temperatures and moisture contents.Meanwhile,the thermal conductivity of these five coal samples was measured by the LFA457 laser thermal conductivity meter.In addition,the Pearson correlation coefficient methodwas applied to explore the effect of different coal compositions on thermal conductivity.The results indicate that the thermal conductivity of coal samples is negatively correlated with thecoal rank.In another word,lower thermal conductivity is associated with higher coal rank.When temperature is-50～10 ℃,the thermal conductivity of coal increases swiftly with the increase of temperature.When temperature is10～50 ℃,the thermal conductivity of coal increases slowly and then tends to be stable.A lower degree of coal maturity indicates a greater effect of moisture content on thermal conductivity.It is also found that ash has the most significant influence on thermal conductivity of coal,then followed by fixed carbon,volatile matter,and moisture.This experimental study provides an understanding of influence factors and variation laws of thermal conductivity of different ranks of coal,and further provides a theoretical basis for the prevention and control of coal fire disasters.
引文
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[9]文虎,王栋,赵彦辉,等.水浸煤体自燃特性实验研究[J].煤炭技术,2015,34(1):261-263.WEN Hu,WANG Dong,ZHAO Yanhui,et al.Experimental study on coal spontaneous combustion characteristics of soaked[J].Coal Technology,2015,34(1):261-263.
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[11]褚廷湘,李品,余明高.水分相变下松散煤体导热系数的数值模拟研究[J].煤炭学报,2017,42(7):1782-1789.CHU Tingxiang,LI Pin,YU Minggao.Simulation study of water phase transition effects on thermalconductivity of loose coal[J].Journal of China Coal Society,2017,42(7):1782-1789.
[12]张绍良,张国良.灰色关联度计算方法比较及其存在问题分析[J].系统工程,1996(3):45-49.ZHANG Shaoliang,ZHANG Guoliang.Comparison of grey relational degree calculation methods and analysis of existing problems[J].Systems Engineering,1996(3):45-49.
[13]谭鹏,李鑫,张小培,等.基于工业分析的煤质发热量预测[J].煤炭学报,2015,40(11):2641-2646.TAN Peng,LI Xin,ZHANG Xiaopei,et al.Prediction of coal heating value based on proximate analysis[J].Journalof China Coal Society,2015,40(11):2641-2646.
[14]MANH D T,SANG K Y,KANG G O,et al.Thermal conductivity of controlled low strength material(CLSM)made entirely from by-products[J].Key Engineering Materials,2018,773:244-248.
[15]谭永波,韩继国,时成林,等.煤矸石材料对道路冻深影响的试验分析与实际观测[J].公路交通科技:应用技术版,2015(8):37-40.TANG Yongbo,HANG Jiguo,SHI Chenglin,et al.Experimental analysis and actual observation of the influence of coal gangue materials on road freezing depth[J].Journal of Highway and Transportation Research and Development,2015(8):37-40.
[16]杨宏民,鲁小凯.变质程度对CO2置换煤CH4效应的影响规律[J].中国安全生产科学技术,2017,13(9):41-46.YANG Hongmin,LU Xiaokai.Influence laws of metamorphic degree on replacement effect of CO2to CH4in coal[J].Journal of Safety Science and Technology,2017,13(9):41-46.
[17]戴广龙.煤低温氧化过程中微晶结构变化规律研究[J].煤炭学报,2011,36(2):322-325.DAI Guanglong.Research on microcrystalline structure change regularity in the coal low temperature oxidation process[J].Journal of China Coal Society,2011,36(2):322-325.
[18]王志远,宋凯,张建胜.不同水热解条件下煤结构变化的实验研究[J].煤炭技术,2015,34(3):287-290.WANG Zhiyuan,SONG Kai,ZHANG Jiansheng.Experiment studies on changes of coal structure during hydrothermal treatment[J].Coal Technology,2015,34(3):287-290.
[19]李建伟,葛岭梅,徐精彩,等.松散煤体导热系数测定实验[J].辽宁工程技术大学学报,2004,23(1):5-8.LI Jianwei,GE Lingmei,XU Jingcai,et al.Measurement of thermal conductivity in loose coal bulk[J].Journal of Liaoning Technical University,2004,23(1):5-8.
[20]王凯.陕北侏罗纪煤低温氧化反应性及动力学研究[D].西安:西安科技大学,2015.
[21]MA L,GUO R,GAO Y,et al.Study on coal spontaneous combustion characteristics under methane-containing atmosphere[J].Combustion Science and Technology,2018(10):1-17.
[2]周西华,高政波,李昂,等.煤岩体导热系数试验及单因子方差分析[J].安全与环境学报,2017,17(4):1303-1308.ZHOU Xihua,GAO Zhengbo,LI Ang,et al.Thermal conductivity test and one-way analysis of variance of coal and rock mass[J].Journal of Safety and Environment,2017,17(4):1303-1308.
[3]周西华,徐丽娜,宋东平,等.大同矿区煤的导热系数灰色关联分析及预测[J].中国安全生产科学技术,2016,12(2):78-82.ZHOU Xihua,XU Lina,SONG Dongping,et al.Grey relational analysis and prediction on thermal conductivity of coal in Datong mining area[J].Journal of Safety Science and Technology,2016,12(2):78-82.
[4]周西华,宋东平,白刚,等.煤岩导热特性实验及其对围岩温度场影响[J].辽宁工程技术大学学报:自然科学版,2018,37(2):251-257.ZHOU Xihua,SONG Dongping,BAI Gang,et al.Experiment on thermal conductivity of coal and its influence on temperature distribution of surrounding rock[J].Journal of Liaoning Technical University:Natural Science,2018,37(2):251-257.
[5]岳高伟,雷留鹏,王兆丰,等.高低温环境下松散煤导热系数研究[J].河南理工大学学报:自然科学版,2017,36(2):1-6.YUE Gaowei,LEI Liupeng,WANG Zhaofeng,et al.Thermal diffusivity research of loose coal under high/low temperature environment[J].Journal of Henan Polytechnic University:Natural Science,2017,36(2):1-6.
[6]杨建蒙,吕美娟,邢飞,等.基于热线法的松散煤体导热系数测量及数值模拟研究[J].煤炭科学技术,2017,45(11):149-154.YANG Jianmeng,LYU Meijuan,XING Fei,et al.Measurement and numerical simulation of thermal conductivity of loose coal based on Hotline Method[J].Coal Science and Technology,2017,45(11):149-154.
[7]杨建蒙,吕美娟,邢飞,等.基于热线法的松散煤体导热系数测量及数值模拟研究[J].煤炭科学技术,2017,45(11):154-159.YANG Jianmeng,LYU Meijuan,XING Fei,et al.Measurement and numerical simulation of thermal conductivity of loose coal based on hot line method[J].Coal Science and Technology,2017,45(11):154-159.
[8]WEN H,LU J,XIAO Y,et al.Temperature dependence of thermal conductivity,diffusion and specific heat capacity for coal and rocks from coalfield[J].Thermochim Acta 2015,619:41-47.
[9]文虎,王栋,赵彦辉,等.水浸煤体自燃特性实验研究[J].煤炭技术,2015,34(1):261-263.WEN Hu,WANG Dong,ZHAO Yanhui,et al.Experimental study on coal spontaneous combustion characteristics of soaked[J].Coal Technology,2015,34(1):261-263.
[10]唐明云,张国枢,张朝举,等.平行热线法测定松散煤体导热系数试验[J].矿业安全与环保,2006,33(5):13-15.TANG Mingyun,ZHANG Guoshu,ZHANG Chaoju,et al.Test of thermal conductivity of loose coal body by parallel hot line method[J].Mining Safety and Environmental Protection,2006,33(5):13-15.
[11]褚廷湘,李品,余明高.水分相变下松散煤体导热系数的数值模拟研究[J].煤炭学报,2017,42(7):1782-1789.CHU Tingxiang,LI Pin,YU Minggao.Simulation study of water phase transition effects on thermalconductivity of loose coal[J].Journal of China Coal Society,2017,42(7):1782-1789.
[12]张绍良,张国良.灰色关联度计算方法比较及其存在问题分析[J].系统工程,1996(3):45-49.ZHANG Shaoliang,ZHANG Guoliang.Comparison of grey relational degree calculation methods and analysis of existing problems[J].Systems Engineering,1996(3):45-49.
[13]谭鹏,李鑫,张小培,等.基于工业分析的煤质发热量预测[J].煤炭学报,2015,40(11):2641-2646.TAN Peng,LI Xin,ZHANG Xiaopei,et al.Prediction of coal heating value based on proximate analysis[J].Journalof China Coal Society,2015,40(11):2641-2646.
[14]MANH D T,SANG K Y,KANG G O,et al.Thermal conductivity of controlled low strength material(CLSM)made entirely from by-products[J].Key Engineering Materials,2018,773:244-248.
[15]谭永波,韩继国,时成林,等.煤矸石材料对道路冻深影响的试验分析与实际观测[J].公路交通科技:应用技术版,2015(8):37-40.TANG Yongbo,HANG Jiguo,SHI Chenglin,et al.Experimental analysis and actual observation of the influence of coal gangue materials on road freezing depth[J].Journal of Highway and Transportation Research and Development,2015(8):37-40.
[16]杨宏民,鲁小凯.变质程度对CO2置换煤CH4效应的影响规律[J].中国安全生产科学技术,2017,13(9):41-46.YANG Hongmin,LU Xiaokai.Influence laws of metamorphic degree on replacement effect of CO2to CH4in coal[J].Journal of Safety Science and Technology,2017,13(9):41-46.
[17]戴广龙.煤低温氧化过程中微晶结构变化规律研究[J].煤炭学报,2011,36(2):322-325.DAI Guanglong.Research on microcrystalline structure change regularity in the coal low temperature oxidation process[J].Journal of China Coal Society,2011,36(2):322-325.
[18]王志远,宋凯,张建胜.不同水热解条件下煤结构变化的实验研究[J].煤炭技术,2015,34(3):287-290.WANG Zhiyuan,SONG Kai,ZHANG Jiansheng.Experiment studies on changes of coal structure during hydrothermal treatment[J].Coal Technology,2015,34(3):287-290.
[19]李建伟,葛岭梅,徐精彩,等.松散煤体导热系数测定实验[J].辽宁工程技术大学学报,2004,23(1):5-8.LI Jianwei,GE Lingmei,XU Jingcai,et al.Measurement of thermal conductivity in loose coal bulk[J].Journal of Liaoning Technical University,2004,23(1):5-8.
[20]王凯.陕北侏罗纪煤低温氧化反应性及动力学研究[D].西安:西安科技大学,2015.
[21]MA L,GUO R,GAO Y,et al.Study on coal spontaneous combustion characteristics under methane-containing atmosphere[J].Combustion Science and Technology,2018(10):1-17.