【作者】 梁志桐；

【导师】 喻健良；

【作者基本信息】 大连理工大学 ， 安全工程， 2012， 硕士

【摘要】 沸溢火灾是最严重的油罐火灾模式之一,当含有水垫层的重质油油罐发生火灾时,如果没有及时灭火,经过长时间的燃烧,油罐会发生燃烧油品的沸溢和喷溅现象,喷溅出来的着火油滴和产生的强烈热辐射会严重威胁救援人员和周围设施以及相邻油罐的安全,并带来严重的损失。由于沸溢机理相当复杂,人们还没有完全掌握,有效防治沸溢火灾措施还不成熟。因此,研究沸溢火灾的突变过程和火灾特性,预测和防治沸溢火灾,对于设备防护和人员撤离及减少沸溢火灾损失具有重要意义。本文的主要工作内容和结论如下：(1)搭建了小尺寸原油沸溢火灾实验装置,对直径为100mm、200mm的油罐在不同的油罐填充率、油层高度、油品含水量的条件下进行了系统的火灾实验,获得了沸溢火灾的特征量随时间的变化规律。(2)实验发现,原油沸溢火灾主要有三个阶段：稳态燃烧阶段、沸溢前兆阶段、沸溢阶段。随着油罐填充率及油水比的增大,沸溢发生时间增大。直径200mm的油罐相比直径100mm的油罐更易发生沸溢。通过实验结果,修正了沸溢时间预测模型。(3)实验发现,稳态燃烧阶段水层温度、油水界面温度升高速度几乎一致。在油水界面位置,沸溢发生时温度均达到120℃以上；无论是在稳态燃烧、沸溢前兆还是沸溢阶段,火焰温度波动要远比油及水温度变化强烈。(4)可视化实验发现,当热波传递到油水界面时使水沸腾产生大量的水蒸气,当水蒸气的能量大于油层产生的压力的时候水蒸气会穿过油层并对油水层造成搅动,形成油泡喷溅出去,最终导致沸溢发生。(5)对油罐沸溢火灾的防治措施进行了探讨。在被动防治过程中,利用沸溢时间预测模型结合沸溢前兆时的火灾特性,合理的预测沸溢时间,提出喷溅半径Rs与覆盖半径Rc两个概念；在主动防治研究中,通过实验发现,向油罐中加入硅酸铝棉的厚度超过水垫层的厚度时,对沸溢现象有明显的抑制效果。更多还原

【Abstract】 Boilover accident is one of the most serious oil tank fire models, when the heavy oil tank containing water cushion catches fire, the oil boilover and burning phenomenon will happen to the burning oil if the fire was not put out in time and burns for a long time. The spitting out drops flame and a strong radiation seriously threat to the safety of the rescue workers and the surrounding facilities which can bring serious damage to them. People still can not grasp the mechanism of boilover because of the complexity, boilover fire prevention and control measures are still not mature. Therefore conducting research on boilover accident mutation process and fire behavior has an important significance to equipment protection, personnel leave and reducing the loss caused by boilover accident.The main contents and conclusions in this paper are as follows:(1) Building a small size of crude oil boilover accident experiment device, the systematic fire experiment including different filling rate, oil layer height, water content of the oil in the diameter of100mm and200mm of oil tank was conducted to get variation law of boilover characteristics with time.(2) The experiment results revealed that the boilover accident had three main stages: steady combustion stage, pre-boilover stage and boilover stage. Along with the increase of oil tank filling rate and oil-water ratio, the time before boilover increased. The boilover phenomenon was more likely to happen in the oil tank of diameter of200mm than the tank of diameter of100mm. Boilover time prediction model was modified according to experiment results.(3) The experiments showed that the temperature of water layer and oil-water interface raise at the almost unanimously speed in the steady combustion stage. In oil-water interface position, the temperature reached more than120oC when boilover occurred; whether in steady combustion, pre-boilover or boilover stage, the flame temperature fluctuated far stronger than oil and water temperature.(4) The visualization experiments revealed that when the heat waves passed to the interface of oil-water, the water was boiled and produced a significant amount of water vapor, when water vapor energy were more than the pressure generated from the oil layer, the water vapor would pass through the oil and caused oil-water layer stir, forming oil bubble spitting out, eventually leading to the boilover happening. (5) The oil tank fire prevention and control measures of boilover accidents hazard were discussed in this paper. In passive prevention and control process, boilover time prediction model combining the fire characteristics of the pre-boilover were used to predict the boilover time rationally, and put forward two concepts, the splash radius Rs and the coverage radius Rc; In the active control study, it was found that the aluminum silicate cotton put in oil tank was more thicker than the water layer, the boilover phenomenon could be significantly prevented.更多还原