半间歇均相反应失控风险评估方法的研究

发布时间：2018-08-30 07:53

【摘要】：近年来,国内外的化工安全事故层出不穷,化工安全问题受到了越来越多的关注,相关的研究也取得长足的进步;然而关于化学反应失控风险性评估理论以及相关实验方法目前仍然有待进一步完善和优化。本文主要针对化学反应失控风险评估中的几个重要问题和参数,即危险化学反应的研究方法、绝热条件下反应能够达到的最高温度(MTSR)、最大反应速率到达时间(TMRad),进行了系统的研究;提出了基于恒温量热法的自催化动力学表征方法,建立了确定TMRad的新的计算方法,确立了基于操作条件和反应动力学的半间歇均相反应失控判据。为失控反应风险性评估方法的完善,提供了理论基础。首先,基于恒温量热法,建立了自催化动力学表征方法。通过比较自催化模型和二级动力学模型对恒温模式下实验数据的拟合效果来判断出反应的自催化特性以及获到相应的动力学参数。实验结果表明:自催化动力学模型对实验结果的拟合效果要优于二级动力学模型,同时通过自催化动力学模型计算得到的反应热相比二级动力学模型更加接近实验值,从而验证了反应的自催化特性以及本方法的有效性。其次,在建立了等温均相半间歇反应的无量纲数学模型基础之上,通过数值模拟和实验验证的手段研究了累积度和MTSR随模型参数的变化规律。数值计算结果表明随着模型参数的不同,MTSR随温度的升高可能是单调增加,也可能会呈现出“S”形变化。提出了一个内含所有模型参数的半经验判据,用于判断MTSR随温度的变化规律,并通过丙酸酐和仲丁醇的酯化反应实验验证了上述判据的有效性。此外,由于反应失控发生或者反应机理复杂,利用ARC进行绝热量热实验室常常无法测得反应放热的终点。对于无放热终点温度的失控反应情形,本文提出了一种新的计算方法以确定体系的TMRad,并且该方法既适用于无放热终点温度的情形,也适用于有放热终点温度的情形。通过硝基化合物和二叔丁基过氧化物/甲苯混合液的绝热量热实验验证了这种方法的有效性。最后,从均相半间歇反应数学模型的非线性分析出发,提出了一种新的反应失控判据-绝热判据。通过数值模拟和实验验证了该判据的有效性。绝热判据既适用于恒温操作模式,又适用于等温操作模式。同时可以用来确定反应过程中的临界累积度。为反应失控评估提供理论基础。
[Abstract]:In recent years, chemical safety accidents at home and abroad have emerged one after another, chemical safety problems have received more and more attention, and the related research has made great progress. However, the theory of chemical reaction runaway risk assessment and related experimental methods still need to be further improved and optimized. This paper mainly aims at several important problems and parameters in risk assessment of chemical reaction runaway, that is, the research method of dangerous chemical reaction. The maximum reaction rate of (MTSR), under adiabatic condition, the maximum reaction rate of (TMRad), the autocatalytic kinetic characterization method based on isothermal calorimetry, and a new calculation method for determining TMRad are proposed. Based on the operation conditions and reaction kinetics, the criterion of semi-batch homogeneous phase reaction runaway is established. It provides a theoretical basis for the improvement of risk assessment method for runaway reaction. Firstly, based on the isothermal calorimetry, the autocatalytic kinetic characterization method was established. The autocatalytic characteristics of the reaction and the corresponding kinetic parameters were determined by comparing the fitting effect of the autocatalytic model and the second-order kinetic model to the experimental data under the constant temperature mode. The experimental results show that the autocatalytic kinetic model fits the experimental results better than the second-order kinetic model, and the reaction heat calculated by the autocatalytic kinetic model is closer to the experimental value than the second-order kinetic model. The autocatalytic properties of the reaction and the effectiveness of the method are verified. Secondly, based on the dimensionless mathematical model of isothermal homogeneous semi-batch reaction, the variation of accumulation degree and MTSR with model parameters are studied by numerical simulation and experimental verification. The numerical results show that the MTSR may increase monotonously with the increase of temperature with different parameters of the model, and it may also show a "S" shape change. A semi-empirical criterion containing all the parameters of the model is proposed to judge the variation of MTSR with temperature. The effectiveness of the criterion is verified by the esterification experiments of propionic anhydride and secondary butanol. In addition, because the reaction is out of control or the reaction mechanism is complex, the endpoints of reaction exothermic can not be measured by using ARC in adiabatic heat laboratory. In this paper, a new calculation method is proposed to determine the TMRad, of the system in the case of uncontrolled reaction without the exothermic end point temperature. This method is suitable for both the case of no end point temperature and the case of the case with the end point temperature of exothermic heat. The effectiveness of this method was verified by the adiabatic thermal experiments of nitro compounds and tert-Ding Ji peroxides / toluene mixtures. Finally, based on the nonlinear analysis of the mathematical model of homogeneous semi-batch reaction, a new criterion, adiabatic criterion, is proposed. The validity of the criterion is verified by numerical simulation and experiments. The adiabatic criterion is not only suitable for constant temperature operation mode, but also suitable for isothermal operation mode. It can also be used to determine the critical accumulation degree in the reaction process. It provides a theoretical basis for the evaluation of reaction out of control.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ086

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