Simulation Experimental Study Of The Small Size Of Oil Boilover

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.