Study on Explosion Safety of Storage of Alcohol/Gasoline Blend Fuels

甲醇、乙醇和以其为主要成分的乙醇混合燃料有望成为可行的替代燃料。酒精混合燃料包括形成丰富混合物或超过可燃上限的混合物的成分，由于在液体表面形成易燃混合层的可能性通常比纯甲醇或乙醇小，因此在安全存储方面具有优势。然而，在瞬变过程中或在大型容器中，仍然存在厚重易燃层的可能性。因此，了解爆炸特性是非常重要的。本研究利用小型容器对甲醇/汽油混合燃料储存的爆炸安全性进行了研究。燃料以覆盖底部的方式提供，对于不同的初始温度、汽化时间、火花间隙高度，混合气被点燃。前半部分考察了包括商用白汽油在内的M100、M97、M95，后半部分考察了包括7种纯成分组成的模型汽油在内的M95、M90和M85。确定了几种典型的压力波动模式。在火花隙高度-汽化时间平面上绘制了最大压升和爆炸范围的等高线。结果表明，在20ﾟC以下，甲醇-空气平衡混合物处于稀薄状态，在较小的汽油含量范围内，爆炸范围和最大压力升高首先随汽油含量的增加而增大，除该区域外，爆炸范围随汽油含量的增加而缩小，最大压力升高随汽油含量的增加而减小。观测到的最大压力升幅至少为1个大气压，通常情况下可达到3至8个大气压。这些结果表明，如果不完全排除点火源，应使容器承受预期的压力升高，或增加汽油含量。

Methanol, ethanol, and alcohol blend fuels including them as main component are expected as feasible alternative fuels.Alcohol blend fuels that include components forming rich mixture or mixture beyond the upper flammable limit have advantages in safety storage since the possibility of forming flammable mixture layr on the liquid surface is usually smaller than that for pure methanol or ethanol. However, in transient processes or in large containers, the possibilities of thick flammable layr still remain. Therefore, it is important to understand explosion characteristics. In this study, explosion safety of storage of methanol/gasoline blend fuels was explored by using small vessels. The fuel was provided so as to cover the bottom, and for various sets of initial temperature, vaporized time, spark gap height, the mixture was ignited. In the former half of the projeic term, M100, M97, M95 including commercial white gasoline were examined, and in the latter half, M95, M90, and M85 including model gasoline consisting of seven pure components were examined. Several typical patterns of pressure fluctuation were identified. The contours of the maximum pressure rise and the range of explosion were plotted in the spark gap height-vaporized time plane. From the plots it was inferred that below 20ﾟC,where methanol-air mixtures in equilibrium are lean, within small gasoline content the range of explosion and maximum pressure rise increase with the content at first, and that except this region the exploded range is shrunk and the maximum pressure rise decreases with the increase of gasoline content. The observed maximum pressure rise is at least 1 atm and in usual cases it reaches 3 to 8 atms. These results indicate that if the ignition source is not excluded completely, the container to bear with expected pressure rise, or the increase of gasoline content should be necessary.