二氯甲烷和甲醇混合物爆炸下限的试验研究

Experimental study on lower explosive limits of dichloromethane-methanol blends

为研究二氯甲烷和甲醇混合物的燃爆危险特性,采用FRTA爆炸极限测试仪测试研究不同混合比例的二氯甲烷和甲醇混合物的爆炸下限,分析不同混合比例、初始温度对混合物爆炸下限的影响。试验结果表明:混合物爆炸下限随二氯甲烷体积分数的增大而升高;随着初始温度从20℃升高至100℃,混合比例为88∶12和92∶8的二氯甲烷和甲醇混合物的爆炸下限均呈下降趋势,两种样品的爆炸下限从12.86%和13.60%分别降至10.15%和10.70%;初始温度在20~100℃范围内,混合物的爆炸下限下降速率较大,下降幅度分别为21.1%和21.3%,明显高于丙烷、氨气和甲醇汽油等。运用数值分析原理拟合了二氯甲烷和甲醇混合物爆炸下限随温度变化的规律函数,为相关生产环境的探测预警和防爆设计提供参考依据。

For researching the burning and explosion characteristics of dichloromethane-methanol blends,FRTA explosion limits in-strument was used to determine lower explosive limits of samples being mixtures of dichloromethane and methanol liquid.Effects of volume fraction of dichloromethane and that of temperature on the lower explosive limits of the samples were studied.The results showed that the lower explosive limit of dichloromethane-metha-nol blends rises with the increase of the dichloromethane volume fraction.The lower explosive limits of dichloromethane-methanol blends showed a decrease trend with the initial temperature changed from 20℃to 100℃.For the blends that mixing ratios of dichloromethane to methanol are 88∶12 and 92∶8,measurement re-sults indicated that the LEL of the blends vapor are 12.86%and 13.60%at 20℃and 10.15%and 10.70%at 100℃.With the tem-perature raising from 20℃to 100℃,the decreasing rates of LEL of samples being mixtures of dichloromethane and methanol are much higher than that of propane,ammonia and methanol gasoline.Besides,the correlations between LEL and initial temperature are founded through numerical analysis,which can be the reference for the detection and explosion proof design under relative production environment.