有毒化学物质瞬时泄漏无风大气扩散的危害后果模拟分析

Simulation Assessment of Hazardous Consequence of Poisonous Material Diffused into Atmosphere under Instantaneous Leakage and Windless Condition

目的建立对有毒气体或高挥发性有毒化学品意外泄漏在大气扩散危害后果数值模拟与预测的方法,为突发化学危害性公共卫生事件应急处置提供事故危害分析信息和可供建设项目职业病危害预评价工作应用。方法利用国家环境保护行业标准推荐的描述有毒气体扩散的数学模型和中毒伤亡后果分析的概率函数法结合计算机软件开发技术,设计开发毒气扩散危害分析软件。结果在高斯气团模型基础上推导了对瞬时泄漏点源毒物在无风情况大气扩散的危害影响范围、危险期等危害后果的一系列定量计算公式,开发设计了实现相应的自动计算和绘图的计算机程序软件TDA2.0,TDA2.0可给出毒气扩散浓度的时空分布分析数据并自动根据中毒概率函数法给出总毒性负荷数值、人员中毒伤亡概率值及人员中毒死亡百分率的预测值。应用TDA2.0对一液氨槽罐车泄漏事故案例作了危害后果模拟分析,估算结果与案例情形基本相符。结论应用该文的危害后果分析定量计算公式和TDA2.0软件能快速得到毒气扩散对点、区间、区域面危害后果的数值模拟预报信息,使用简便有效。

Objective To establish numerical simulation and forecast method for hazardous consequence of toxic gas or volatile poisonous material which suddenly leak and diffuse into atmosphere under windless condition, so as to provide information on accident hazards analysis for public health emergency disposal and for pre-assessment of occupational hazards in construction project. Methods Based on the mathematical models of poisonous gas diffusion and poisoning casualty probability function method which are recommended by Nation Environmental Protection Standards,using computer programming method,the computer software is designed for hazard analysis of toxic gas diffusion. Results Based on Gaussian air mass model a series of calculation formulas are obtained for assessment of hazardous scope and consequence of poisonous material diffused into atmosphere under instantaneous leakage and windless condition., Excel template software TDA2.0 is developed. Using TDA2.0 program, the data on time-space distribution of toxic gas can easily be present. The total toxicity load and the probability of human poisoning or death can be calculated with program of poisoning probability function. This TDA2.0 program was applied to analyze the hazard consequence of liquid ammonia leakage from a tank-car. The calculated results were almost same as the reality. Conclusion TDA2.0 software is convenient and helpful tool to quickly predict the time-space distribution of toxic gas and its consequences.