甲苯-环己烷混合气体燃爆特性试验研究

Experimental study on the explosive characteristics of toluene and cyclohexane mixture

针对挥发性有机物(Volatile Organic Compounds,VOCs)治理工程易发生的有机气体燃爆问题进行研究,以甲苯、环己烷2种典型VOCs气体为研究对象,研究其在不同条件下闪点、自燃点和爆炸下限的变化规律。结果表明,随混合样品中甲苯体积分数增加,混合蒸气的闪点由-17℃增加到9℃,自燃温度由264.1℃增加至515.9℃,爆炸下限由0.917%上升到1.252%。当混合样品中闪点、自燃温度和爆炸下限均较低的环己烷体积分数增大时,气体混合物的燃爆危险性相应增大。甲苯-环己烷混合样品(体积比为1∶1)的自燃点随质量浓度增加呈现先降低后上升的趋势,质量浓度为0.417 g/L时自燃温度最低,为461.82℃,混合样品在此质量浓度下最易发生自燃。当初始温度从65℃上升到165℃时,甲苯-环己烷混合蒸气(体积比为1∶1)爆炸下限降低,由1.310%降至0.980%,初始温度升高使混合气体爆炸的危险性增大。

This article focuses on the problem of organic explosions that are prone to occur in the ecological engineering of organic compounds(VOCs).Multi-component VOCs(toluene/cyclohexane)were investigated and the explosion hazard in the production process of toluene and cyclohexane was explored.The flashpoint,spontaneous ignition point,and lower explosion limit under different conditions were studied.The flashpoint of toluene/cyclohexane at different volume fraction ratios was measured by the micro continuous closed flash point meter.The changing of the spontaneous combustion temperature of toluene-cyclohexane at different volume ratios and different concentrations was determined with the liquid spontaneous ignition point tester.The Lower Explosion Limit(LEL)of the mixed-VOCs under different volume fraction ratios and different initial temperatures was tested with the liquid explosion limit tester.The results show that with the increase of the toluene volume fraction in the mixed sample,the flashpoint of the toluene/cyclohexane increases from-17℃to 9℃;when the toluene volume fraction is in the range of 90%-100%,the flashpoint rising rate is fastest;the auto-ignition temperature increases from 264.1℃to 515.9℃.When the toluene volume fraction is 70%-100%,the spontaneous combustion temperature of the mixed liquid increases from 287.4℃to 515.9℃;the lower explosion limit rises from 0.917%to 1.252%.When the toluene volume fraction is in the range of 80%-100%,the explosion lower limit of mixed vapor increases the fastest.The character of lower flash point,higher auto-ignition temperature,and lower explosive limit would aggravate the explosion hazard of the multi-component VOCs.The spontaneous ignition point of the toluene/cyclohexane(volume fraction of 1∶1)shows a decreasing trend at first and then increases with increasing concentration.The spontaneous ignition temperature achieves the lowest of 461.82℃when the concentration of toluene is 0.417 g/L,indicating that it is the most prone to spontaneous combustion.When the initial temperature rose from 65℃to 165℃,the lower explosion limit of toluene/cyclohexane decreases from 1.310%to 0.980%.The increase of the initial temperature will increase the risk of the explosion of the multi-component VOCs.