Study On Thermal Runaway Mechanism And Inherently Safe Operation Of Isoperibolic Semibatch Homogeneous Reactions

The chemical industry has brought great convenience for the humans’daily life.However,it has brought many disasters as well because of many safety problems.In recent years,many scholars at home and abroad have conducted in-depth studies on the safety of chemical process,and the critical criterion of chemical reaction thermal runaway and the practical application have achieved good results and great progress.However,there are some limitations in the theory of thermal risk evaluation.The main research object of this paper is the isoperibolic semi-batch homogeneous reactions in the fine and pharmaceutical industry.Based on the equations of mass and energy balance,a mathematical model of desired reaction and secondary effect is established.MTSR is a very important parameter in the risk assessment of chemical reactions.However,the variation of MTSR is blank in the isoperibolic semi-batch homogeneous reactions.This paper investigates the variations of MTSR for the first time.Two new parameters are defined.One is time to MTSR of the synthesis reactionθ_MTSR,and the other is normalized objective sensitivity ofθ_MTSRwith respect to any input parameters?,S(θ_MTSR)_?.Through numerical calculation of variation of MTSR₀,θ_MTSR and S(θ_MTSR)?as a function of jacket temperature,a new critical criterion is proposed and defined as MTSR criterion.The proposed MTSR criterion used to identify different thermal behavior of isoperibolic semi-batch homogeneous reactions,including no ignition,thermal runaway,QFS and secondary effect situations has an advantage that both desired reaction and secondary effect have been considered conveniently.Based on MTSR criterion,MQFS and GIS operating regions have been proposed,and meanwhile the optimization algorithm to identify those regions has been established in this paper.Through the integration of model parameters,two operating diagrams have been introduced,by which the inherently safe operating conditions of chemical reactions can be identified only by several tests from calorimeters.Finally,MTSR criterion has been systematically verify by hydrolysis experiments of mole ratio of acetic anhydride and deionized water.Methods to obtain the thermodynamic and dynamic data of the established mathematical model,operation of calorimeters,as well as the design of verification experiment have been presented,to provide the reader with an example of experimental method and numerical simulation of acetic anhydride hydrolysis reactions.