圆筒形液化气储罐泄漏火灾超压失效预测研究

Overpressurization prediction for cylinder tank of LPG due to leakage fire

面向常见圆筒形液化气储罐,针对导致事故发生的火灾提升罐内压力,压力促进泄漏,泄漏加剧火灾的根源性原因,基于质量、能量守恒方程以及压力容器破裂预测公式,建立经实际事故验证的储罐泄漏火灾失效预测模型。通过对罐内压力的分析,当罐内液相被火灾加热时,泄漏液化气喷射火和池火都可造成储罐超压失效,且喷射火可更快导致储罐超压。储罐充装系数越高,超压失效时间越短,危险性越大。针对储罐不同泄漏孔径的研究表明,当泄漏孔径小于安全临界泄漏孔径时储罐不会超压失效,当泄漏孔径等于最危险泄漏孔径时储罐超压失效时间最短。液化气储罐如发生泄漏火灾,建议根据气相或液相加热、火灾类型、泄漏孔径等审慎判断事故情况,再决定救援方案,并时刻提防罐体超压失效引发的爆炸。

The LPG tanks with the form of cylinder shape are taken into investigation,the root cause of the overpressurization is that the fire increases the pressure in the tank,then the pressure promotes the leak,and the leak aggravates the fire again.Combining the equations of mass and energy conservation,the Hertz-Knudsen equation,the prediction formula for pressure vessel rupture and so on,the model for overpressurization of cylinder tank of LPG due to leakage fire is established and then verified by an accident.Through the analysis of the pressure in the tank during the accident,when the liquid phase of LPG in the tank is heated by fire,both the jet fire and pool fire of LPG can cause the tank to fail due to overpressure,and the tank is broken more quickly under jet fire.The overpressurization time for the tank is shorten with high filling coefficient.With the analysis of tank overpressurization under the conditions of various leak sizes,the tank will not fail when the leak size is less than the safety critical leak size,and the tank fails fastest when the leak size is equal to the most dangerous leak size.In the event of a leakage fire of LPG tank,it is recommended to judge the accident situation carefully according to gas phase or liquid phase heating,fire types,leak sizes,etc.,then decide on the emergency plan,and always beware of explosion caused by overpressure failure of tank.