安全壳压力试验中多元混合可燃性气体的爆炸极限研究

The Study of the Flammability Limits of the Multicomponent Gas in the Containment Pressure Test

在核电站安全壳压力试验过程中,由于涂层油漆及维修化学药品挥发而产生的可燃气体易发生扩散、富集现象,加之于高温高压的试验环境,进一步增加了火灾发生的风险。为提高压力试验的安全性和可靠性,本文基于爆炸极限试验模拟及理论模型计算,对压力试验环境下7种常见的可燃性气体及其混合可燃物的爆炸极限变化规律展开研究。研究结果表明:安全壳内混合可燃物中苯、二甲苯、乙酸乙酯、甲苯等爆炸下限较低的可燃性气体所占的体积分数越大,压力试验过程中发生火灾的风险越高;初始压力的增加增大而造成爆炸的可能性较小;爆炸极限范围随着初始温度的升高而增大,尤其是爆炸下限的降低增加了安全壳内可燃气体爆炸的风险性。

During the nuclear power plant containment pressure test,the combustible gas is easy to spread and enrich due to the volatilization of coating paint and maintenance chemicals.In addition,the high temperature and high pressure test environment further increases the risk of fire.In order to improve the safety and reliability of the pressure test,based on the explosion limit test simulation and theoretical model calculation,this paper studied the change rules of the explosion limit of 7 common combustible gases and their mixtures under pressure test environment.The results show that the higher the volume fraction of combustible gases with lower explosion limit,such as benzoic,xylene,ethyl acetate and toluene,the higher the risk of fire in the process of pressure test.Although the increase of initial pressure leads to the increase of the upper limit of the explosion of the mixed combustible gas,the possibility of explosion caused by the increase of pressure is small because most of the combustible gas during the containment pressure test comes from the volatilization of the protective coating and its concentration is low and difficult to reach the upper limit of the explosion of combustible gas.The explosion limit range increases with the increase of initial temperature,especially the reduction of the explosion limit increases the risk of combustible gas explosion in the containment.