Explosion characteristics of methane-air mixture near lower explosion limit at different relative humidities
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摘要: 为了研究不同湿度条件下低浓度甲烷-空气混合物爆炸特征,设计了饱和湿空气发生及储存装置,对管路、气囊和爆炸腔体进行温度控制和流量调节,实现了不同相对湿度的甲烷-空气混合气体的配置。采用20 L球形爆炸测试装置,分析不同相对湿度、甲烷浓度对混合物的最大爆炸压力、最大压力上升速率、爆炸下限及层流燃烧速度的影响。结果表明,随着相对湿度增大,最大爆炸压力和最大爆炸压力上升速率逐渐下降,且呈一定的线性关系。混合气体相对湿度从27.7%增大到80.1%时,甲烷爆炸下限从5.15%上升到5.25%,上升率1.9%,层流燃烧速度随相对湿度的增大也呈线性降低趋势。在本文条件下,相对湿度对甲烷-空气混合物的爆炸影响较小,这主要与常温常压下水蒸气的饱和分压力较低有关,但在高温高压时仍需考虑水蒸气含量的增大对混合气体爆炸特征的影响。Abstract: To explore the explosion characteristics of methane-air mixtures with low concentration of methane at various humidities, a device for producing and containing water-saturated air was developed. The temperature and flow of pipes, air bag and explosion vessel were controlled to obtain methane-air mixture with variable humidity. The 20 L spherical explosion vessel was employed to analyze the effect of relative humidity and methane concentration on methane explosion characteristics (i.e., maximum explosion pressure, maximum rate of pressure rise, lower explosion limit and laminar burning velocity). It is concluded that the maximum explosion pressure and maximum rate of pressure rise show a linear decrease with an increasing value of humidity. As the humidity of gas mixture changes from 27.7% to 80.1%, the lower explosion limit of methane in air increases from 5.15% to 5.25% with a rising rate of 1.9%. The laminar burning velocity performs a similar linear downtrend with the increase of relative humidity. Under the given circumstances, the relative humidity has no significant influence on the explosion characteristic of methane-air mixture, which can be ascribed to the low value of partial pressure of water vapor at ambient condition. However, this influence cannot be neglected as the water vapor increases to a certain extent level at high temperatures and high pressures.
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表 1 甲烷爆炸特征随相对湿度变化的拟合参数
Table 1. Fitted parameters of CH4 explosion characteristics at different relative humidities
φ(CH4)/% a1 b1 $R^2_1 $ a2 b2 $ R^2_1 $ a3 b3 R32 pmax/MPa=a1 Hmix/%+b1 (dp/dt)max/(MPa·s−1)= a2 Hmix/%+b2 SL/(m·s−1)= a3 Hmix/%+ b3 6.5 −0.000 809 0.460 0.951 −0.218 39.510 0.834 −0.000 156 0.208 0.965 6.3 −0.001 220 0.391 0.875 −0.201 32.243 0.798 −0.000 264 0.181 0.965 6.1 −0.001 470 0.248 0.610 −0.147 23.697 0.894 −0.000 140 0.139 0.912 5.9 −0.001 000 0.204 0.628 −0.113 20.102 0.901 −0.000 415 0.114 0.939 表 2 甲烷空气混合物爆炸极限
Table 2. Explosion limits of methane-air mixtures
容器 T0/K p0/kPa Hmix/% W/J 判断标准 φL(CH4)/% φU(CH4)/% 出处 8 L玻璃管 298 100 观察火焰是否传播 5.0±0.1 文献[10] 20 L近球形 298 100 1 升压7% 5.0±0.1 15.9±0.1 文献[10] 120 L球形 298 100 2 升压7% 5.0±0.1 15.7±0.2 文献[10] 3.4 L玻璃管 298 100 52~73 1 观察火焰是否传播 5.15 16.15 文献[22] 12 L球形 308 102 0 10 观察火焰是否传播 4.9±0.1 15.8±0.2 文献[23] 13.3 L 钢管 285~303 100~102 35~80 升压7% 5.2 14.8 文献[20] 20 L球形 298 100 0 10 升压7% 5.0 15.0 文献[24] 20 L球形 298 101 85~100 10 升压7% 6.0 14.0 文献[17] 20 L球形 298 100 0 10 升压7% 5.1 15.8 文献[21] 20 L近球形 299~300 101 65~66 10 升压5%~7% 5.15 15.9 文献[25] 20 L球形 295~298 100 55~70 10 升压7% 5.02 14.55 文献[13] 40 L圆柱形 293 100 升压5% 4.65 15.5 文献[26] -
[1] KUNDU S, ZANGANEH J, MOGHTADERI B. A review on understanding explosions from methane-air mixture [J]. Journal of Loss Prevention in the Process Industries, 2016, 40: 507–523. DOI: 10.1016/j.jlp.2016.02.004. [2] 李润之, 黄子超, 司荣军. 环境温度对瓦斯爆炸压力及压力上升速率的影响 [J]. 爆炸与冲击, 2013, 33(4): 415–419. DOI: 10.11883/1001-1455(2013)04-0415-05.LI R Z, HUANG Z C, SI R J. Influence of environmental temperature on gas explosion pressure and its rise rate [J]. Explosion and Shock Waves, 2013, 33(4): 415–419. DOI: 10.11883/1001-1455(2013)04-0415-05. [3] 罗振敏, 王涛, 文虎, 等. CO对CH4爆炸及自由基发射光谱特性的影响 [J]. 煤炭学报, 2019, 44(7): 2167–2177. DOI: 10.13225/j.cnki.jccs.2018.1123.LUO Z M, WANG T, WEN H, et al. Explosion and flame emission spectra characteristics of CH4-air mixtures with CO addition [J]. Journal of China Coal Society, 2019, 44(7): 2167–2177. DOI: 10.13225/j.cnki.jccs.2018.1123. [4] 罗振敏, 王涛, 程方明, 等. 小尺寸管道内二氧化碳抑制甲烷爆炸效果的实验及数值模拟 [J]. 爆炸与冲击, 2015, 35(3): 393–400. DOI: 10.11883/1001-1455-(2015)03-0393-08.LUO Z M, WANG T, CHENG F M, et al. Experimental and numerical studies on the suppression of methane explosion using CO2 in a mini vessel [J]. Explosion and Shock Waves, 2015, 35(3): 393–400. DOI: 10.11883/1001-1455-(2015)03-0393-08. [5] 钱海林, 王志荣, 蒋军成. N2/CO2混合气体对甲烷爆炸的影响 [J]. 爆炸与冲击, 2012, 32(4): 445–448. DOI: 10.11883/1001-1455(2012)04-0445-04.QIAN H L, WANG Z R, JIANG J C. Influence of N2/CO2 mixture on methane explosion [J]. Explosion and Shock Waves, 2012, 32(4): 445–448. DOI: 10.11883/1001-1455(2012)04-0445-04. [6] 张迎新, 吴强, 刘传海, 等. 惰性气体N2/CO2抑制瓦斯爆炸实验研究 [J]. 爆炸与冲击, 2017, 37(5): 906–912. DOI: 10.11883/1001-1455(2017)05-0906-07.ZHANG Y X, WU Q, LIU C H, et al. Experimental study on coal mine gas explosion suppression with inert gas N2/CO2 [J]. Explosion and Shock Waves, 2017, 37(5): 906–912. DOI: 10.11883/1001-1455(2017)05-0906-07. [7] ZHANG B, XIU G L, BAI C H. Explosion characteristics of argon/nitrogen diluted natural gas-air mixtures [J]. Fuel, 2014, 124: 125–132. DOI: 10.1016/j.fuel.2014.01.090. [8] 余明高, 刘梦茹, 温小萍, 等. 超细水雾-多孔材料协同抑制瓦斯爆炸实验研究 [J]. 煤炭学报, 2019, 44(5): 1562–1569. DOI: 10.13225/j.cnki.jccs.2018.0795.YU M G, LIU M R, WEN X P, et al. Synergistic inhibition of gas explosion by ultrafine water mist-porous materials [J]. Journal of China Coal Society, 2019, 44(5): 1562–1569. DOI: 10.13225/j.cnki.jccs.2018.0795. [9] 裴蓓, 韦双明, 余明高, 等. 气液两相介质抑制管道甲烷爆炸协同增效作用 [J]. 煤炭学报, 2018, 43(11): 3130–3136. DOI: 10.13225/j.cnki.jccs.2018.0064.PEI B, WEI S M, YU M G, et al. Synergistic inhibition effect on methane explosion in pipeline by gas-liquid two-phase medium [J]. Journal of China Coal Society, 2018, 43(11): 3130–3136. DOI: 10.13225/j.cnki.jccs.2018.0064. [10] CASHDOLLAR K L, ZLOCHOWER I A, GREEN G M, et al. Flammability of methane, propane, and hydrogen gases [J]. Journal of Loss Prevention in the Process Industries, 2000, 13(3−5): 327–340. DOI: 10.1016/S0950-4230(99)00037-6. [11] 任常兴, 张欣, 张琰, 等. 可燃气体及混合物爆炸极限影响特征研究 [J]. 消防科学与技术, 2017, 36(11): 1500–1503. DOI: 10.3969/j.issn.1009-0029.2017.11.006.REN C X, ZHANG X, ZHANG Y, et al. Overview on the characteristics of explosion limits of gases and gas mixtures [J]. Fire Science and Technology, 2017, 36(11): 1500–1503. DOI: 10.3969/j.issn.1009-0029.2017.11.006. [12] 谭迎新, 霍雨江, 焦国太, 等. 可燃气体动态爆炸极限测试装置设计 [J]. 消防科学与技术, 2018, 37(9): 1235–1238. DOI: 10.3969/j.issn.1009-0029.2018.09.024.TAN Y X, HUO Y J, JIAO G T, et al. Design of combustible gas dynamic explosion limit test device [J]. Fire Science and Technology, 2018, 37(9): 1235–1238. DOI: 10.3969/j.issn.1009-0029.2018.09.024. [13] 刘丹, 司荣军, 李润之. 环境湿度对瓦斯爆炸特性的影响 [J]. 高压物理学报, 2015, 29(4): 307–312. DOI: 10.11858/gywlxb.2015.04.011.LIU D, SI R J, LI R Z. Ambient humidity influence on explosion characteristics of methane-air mixture [J]. Chinese Journal of High Pressure Physics, 2015, 29(4): 307–312. DOI: 10.11858/gywlxb.2015.04.011. [14] 谭汝媚, 张奇, 黄莹. 环境湿度对环氧丙烷蒸气爆炸参数的影响 [J]. 高压物理学报, 2013, 27(3): 325–330. DOI: 10.11858/gywlxb.2013.03.002.TAN R M, ZHANG Q, HUANG Y. Ambient humidity influence on explosion characteristics parameters of gaseous epoxypropane [J]. Chinese Journal of High Pressure Physics, 2013, 27(3): 325–330. DOI: 10.11858/gywlxb.2013.03.002. [15] 朱丕凯. 环境因素对甲烷爆炸极限浓度的影响研究 [J]. 煤炭技术, 2019, 38(6): 108–111. DOI: 10.13301/j.cnki.ct.2019.06.038.ZHU P K. Study on influence of ambient factors on methane explosive limit concentration [J]. Coal Technology, 2019, 38(6): 108–111. DOI: 10.13301/j.cnki.ct.2019.06.038. [16] 李成兵, 吴国栋, 经福谦. 水蒸气抑制甲烷燃烧和爆炸实验研究与数值计算 [J]. 中国安全科学学报, 2009, 19(1): 118–124. DOI: 10.3969/j.issn.1003-3033.2009.01.019.LI C B, WU G D, JING F Q. Experimental investigation and numerical computation of methane combustion and explosion suppressed by vapor [J]. China Safety Science Journal, 2009, 19(1): 118–124. DOI: 10.3969/j.issn.1003-3033.2009.01.019. [17] SHEN X B, ZHANG B, ZHANG X L, et al. Explosion behaviors of mixtures of methane and air with saturated water vapor [J]. Fuel, 2016, 177: 15–18. DOI: 10.1016/j.fuel.2016.02.095. [18] QI S, DU Y, ZHANG P L, et al. Effects of concentration, temperature, humidity, and nitrogen inert dilution on the gasoline vapor explosion [J]. Journal of Hazardous Materials, 2017, 323: 593–601. DOI: 10.1016/j.jhazmat.2016.06.040. [19] 伯纳德•刘易斯, 京特•冯•埃尔贝. 燃气燃烧与瓦斯爆炸[M]. 王方, 译. 3版. 北京: 中国建筑工业出版社, 2007: 581−584. [20] 王华, 葛岭梅, 邓军, 等. 受限空间可燃性气体爆炸特性的对比 [J]. 煤炭学报, 2009, 34(2): 218–223. DOI: 10.13225/j.cnki.jccs.2009.02.003.WANG H, GE L M, DENG J, et al. Comparaison of explosion characteristics of ignitable gases in confined space [J]. Journal of China Coal Society, 2009, 34(2): 218–223. DOI: 10.13225/j.cnki.jccs.2009.02.003. [21] 高娜, 张延松, 胡毅亭. 温度、压力对甲烷-空气混合物爆炸极限耦合影响的实验研究 [J]. 爆炸与冲击, 2017, 37(3): 453–458. DOI: 10.11883/1001-1455(2017)03-0453-06.GAO N, ZHANG Y S, HU Y T. Experimental study on methane-air mixtures explosion limits at normal and elevated initial temperatures and pressures [J]. Explosion and Shock Waves, 2017, 37(3): 453–458. DOI: 10.11883/1001-1455(2017)03-0453-06. [22] WANG T, LUO Z M, WEN H, et al. Effects of flammable gases on the explosion characteristics of CH4 in air [J]. Journal of Loss Prevention in the Process Industries, 2017, 49: 183–190. DOI: 10.1016/j.jlp.2017.06.018. [23] KONDO S, TAKIZAWA K, TAKAHASHI A, et al. A study on flammability limits of fuel mixtures [J]. Journal of Hazardous Materials, 2008, 155(3): 440–448. DOI: 10.1016/j.jhazmat.2007.11.085. [24] ZHANG B, NG H D. Explosion behavior of methane-dimethyl ether/air mixtures [J]. Fuel, 2015, 157: 56–63. DOI: 10.1016/j.fuel.2015.04.058. [25] 李润之. 点火能量与初始压力对瓦斯爆炸特性的影响研究[D]. 青岛: 山东科技大学, 2010: 50−67. [26] GIERAS M, KLEMENS R, RARATA G, et al. Determination of explosion parameters of methane-air mixtures in the chamber of 40 dm3 at normal and elevated temperature [J]. Journal of Loss Prevention in the Process Industries, 2006, 19(2-3): 263–270. DOI: 10.1016/j.jlp.2005.05.004. [27] 陆胤臣, 陶刚, 张礼敬. 球形容器内甲烷-空气爆炸特性分析与理论计算 [J]. 爆炸与冲击, 2017, 37(4): 773–778. DOI: 10.11883/1001-1455(2017)04-0773-06.LU Y C, TAO G, ZHANG L J. Analysis and theoretical calculation of explosion characteristics of methane-air mixture in a spherical vessel [J]. Explosion and Shock Waves, 2017, 37(4): 773–778. DOI: 10.11883/1001-1455(2017)04-0773-06. [28] LEWIS B, VON ELBE G. Determination of the speed of flames and the temperature distribution in a spherical bomb from time-pressure explosion records [J]. The Journal of Chemical Physics, 1934, 2(5): 283–290. DOI: 10.1063/1.1749464. [29] VAN DEN BULCK E. Closed algebraic expressions for the adiabatic limit value of the explosion constant in closed volume combustion [J]. Journal of Loss Prevention in the Process Industries, 2005, 18(1): 35–42. DOI: 10.1016/j.jlp.2004.10.004. [30] DAHOE A E. Laminar burning velocities of hydrogen-air mixtures from closed vessel gas explosions [J]. Journal of Loss Prevention in the Process Industries, 2005, 18(3): 152–166. DOI: 10.1016/j.jlp.2005.03.007. [31] MIAO H Y, JI M, JIAO Q, et al. Laminar burning velocity and Markstein length of nitrogen diluted natural gas/hydrogen/air mixtures at normal, reduced and elevated pressures [J]. International Journal of Hydrogen Energy, 2009, 34(7): 3145–3155. DOI: 10.1016/j.ijhydene.2009.01.059. [32] LIAO S Y, JIANG D M, CHENG Q. Determination of laminar burning velocities for natural gas [J]. Fuel, 2004, 83(9): 1247–1250. DOI: 10.1016/j.fuel.2003.12.001. [33] HAN G Z, HU Q X. Effects of electric field on saturated vapor pressure [J]. The Journal of Physical Chemistry C, 2020, 124(3): 1820–1826. DOI: 10.1021/acs.jpcc.9b09825. [34] WANG S M, WU D J, GUO H, et al. Effects of concentration, temperature, ignition energy and relative humidity on the overpressure transients of fuel-air explosion in a medium-scale fuel tank [J]. Fuel, 2020, 259: 116265. DOI: 10.1016/j.fuel.2019.116265. [35] LIANG Y T, ZENG W. Numerical study of the effect of water addition on gas explosion [J]. Journal of Hazardous Materials, 2009, 174(1−3): 386–392. DOI: 10.1016/j.jhazmat.2009.09.064. [36] ZHANG P L, DU Y, WU S L, et al. Experiments of the secondary ignition of gasoline-air mixture in a confined tunnel [J]. Journal of Thermal Analysis and Calorimetry, 2014, 118(3): 1773–1780. DOI: 10.1007/s10973-014-4082-y.