霉变对储存水稻燃烧行为影响的研究

储存水稻火灾危险性研究具有重要意义。通过研究霉变对储存水稻燃烧行为的影响,确定其火灾危险性。锥形量热燃烧实验(Cone Test)结果显示,霉变样品可以在更小的外加辐射下被点燃;在四种热辐射(25 kW/m2,35 kW/m2,45 kW/m2,55 kW/m2)下,霉变样品的着火时间(TTI)与火灾性能指数(FPI)均小于未霉变样品;而火灾蔓延指数(FGI)高于未霉变样品。Cone Test结果表明霉变显著提高了储存水稻的火灾危险性。差示扫描量热仪(DSC)测试发现在低温时霉变样品比未霉变时吸热焓值提高了3.6倍,表明其析出了更多的小分子挥发物。结合气相质谱联用(GC-MS)测试确定了霉变样品析出的挥发物中含有醇类, 酯类和醛类等易燃物。采用稳态管式炉(SSTF)进一步研究储存水稻的充分燃烧行为,结果显示热释放量及烟气毒性与样品质量(20 g,40 g)以及一次进气量(10 L/min,20 L/min,30 L/min)有关,霉变对于两者的影响较小。

Influence of mold on the combustion behavior of storage rice

The study on the fire risk of storage rice has a huge significance. The objective of this study is to validate the effect of mold on the combustion behavior of storage rice and determine its fire risk. The cone test results showed that the mold-free samples could be ignited under a lower external heat flux, comparing with the mold-free samples. The ignition time (TTI) and fire performance index (FPI) of moldy samples were less than those of mold-free samples under four kinds of radiation (25 kW/m2, 35 kW/m2, 45 kW/m2, 55 kW/m2). Besides, the fire growth index (FGI) was higher than that of the mold-free samples, indicating that the mold significantly increased the fire risk of storage rice. The differential scanning calorimetry (DSC) results showed that the moldy rice had a higher endothermic enthalpy value, which increased about 360% compared with that of the mold-free samples at low temperatures. Additionally, gas chromatography-mass spectrometry (GC-MS) test results showed that the alcohols, esters and aldehydes were produced at the moldy process. The Steady-state tube furnace (SSTF) was used to study the combustion behavior. The results indicated that the heat release and smoke toxicity were related to the quality of samples (20 g, 40 g) and primary air supply (10 L/min, 20 L/min, 30 L/min). The effect of mold is not of great significance.