自反应性化学物质热危险性综合评估

自反应性化学物质热危险性评估的关键在于表征参数的选择和量化,单一的评估参数往往仅表征其热危险性的某一方面。综合考虑自反应性物质发生热分解反应的难易程度及其造成后果的严重程度两个方面,分别选取放热反应初始温度(To)和反应热(-ΔH)作为相应的表征参数,通过半正态分布函数对这两个指标进行标准化处理。在此基础上根据风险的定义提出了一种新的自反应性化学物质的热危险性综合评估指数(THI指数),并建立相应的热危险性分级标准,对自反应性化学物质的热危险性进行综合评估与分级。结果表明,建立的THI指数所确定的热危险性分级结果与基于活化能和最大绝热温度的RHI指数的反应危险性等级基本一致,该指数能够对自反应性化学物质的热危险性进行定量评估。

On the thermal hazard evaluation for some self-reactive substances

The aim of this paper is to propose a renovated simple and general method to assess the thermal hazards likely to be caused by the self-reactive chemicals,which can make up for the inadequacy of the traditional experimental methods.The thermal hazards,one of the most important characteristic self-reactive chemicals,may include the spontaneous combnstion,the thermal decomposition and thermal explosion.The key to the thermal hazard assessment for the self-reactive substances is to properly choose and quantify the various assessment parameters.Nevertheless,traditional single parameters are usually featured with a single aspect of the thermal hazard.What is more,we have chosen the onset temperature (To) and the heat of reaction (-△H) as the parameters for characterizing the probability and severity of the thermal decomposition,respectively,whereas the half normal distribution function has been adopted for the dimensionless treatment to reduce the loss of the information in data.On the other hand,the new index THI (the thermal hazard index) can correspondingly be defined as the product of the dimensionless values of To and-△H.Furthermore,we have managed to establish a ranking standard of thermal hazard based on the new indexes and divided the thermal risk liabilities into five levels with equal intervals through preliminary gradation.Besides,the critical values of the grade classification can further be modified through a nonlinear fuzzy model.In order to test the validity of the proposed THI indexes,the thermal hazards of the self-reactive chemicals to be used can be assessed by using the traditional reaction hazard index (RHI) system to represent the reaction hazards based on the activation energy and the adiabatic time even at the maximum rate in reference to the previous literatures.The results of our investigation suggest that both the indices can provide consistent thermal hazard rank parameters for the involved chemicals.More detailed comparisons between these two indices can be done further to prove the superiority of the presented method and demonstrate that the method we have developed can be effectively used to estimate the thermal hazards of self-reactive chemicals in chemical industry and the engineering practice.