苯和甲苯硝化及磺化反应热危险性分级研究

首先介绍了化工工艺热安全性的内涵,并从反应过程热危险性分析的方法学出发,介绍间隙、半间歇化学反应工艺热危险性分级研究的总体思路及方法。然后,围绕甲苯和苯的硝化、磺化反应,用全自动反应量热仪(RC1e)和加速度量热仪(ARC)测定其反应过程的绝热温升(△Tad)、目标反应所能达到的最高温度(TM)、分解反应最大速率到达时间(θD)等参数。运用风险评价指数矩阵法(方法1)和基于失控过程温度参数的热危险评估法(方法2)分别对其硝化和磺化反应过程的热危险性进行了分级评估。结果表明,这两种方法具有良好的一致性;给定工艺条件下甲苯和苯的一段硝化反应过程的热危险度等级较低;而磺化反应的热危险较高。尽管这两种方法还有一定的局限性,但对于间歇、半间歇合成工艺的本质安全化设计、工艺热危险性的评估具有重要的参考价值和实用意义。

Classification Investigation on Thermal Hazards in Nitration and Sulfonation Reactions of Benzene and Toluene

The connotation of thermal safety of chemical process was introduced firstly, and the general idea and related methods on the thermal hazard classification of chemical synthesis reactions were also introduced methodologically. Aiming at the nitration and sulphonation processes of benzene and toluene, reaction calorimeter (RC1e) and accelerating rate calorimeter (ARC) were employed to test parameters of adiabatic temperature rise (△Tad), maximal temperature attainable by runaway of the desired synthesis reaction (TM), time to maximum rate of second decomposition reaction under adiabatic conditions (θD), etc. The method of risk assessment code matrix (method 1) and thermal hazard assessment method which is based on temperature parameters in runaway scenario (method 2) were applied to evaluate and classify the thermal hazards of nitration and sulphonation processes of benzene and toluene. The obtained results show that the two methods are of good agreement. Thermal criticalities of mononitration processes of benzene and toluene at given conditions are assessed lower, while that of sulphonation processes are higher. Two thermal criticality assessment methods are of great reference and practice to the inherent safe process design of batch and semi-batch reactions, and to the chemical process assessment, although they all have some restrictions.