Facile Approach To Design Thermally Safe Operating Conditions for Isoperibolic Homogeneous Semibatch Reactors Involving Exothermic Reactions

Abstract

To prevent thermal runaway incidents in semibatch reactors (SBRs), designing thermally safe operating conditions should be considered first. Regretfully, determination of the reaction kinetics for organic reactions is a timeconsuming and money-consuming process, especially in the fine chemical and pharmaceutical industries. Therefore, it is desirable to develop kinetic-parameter-free methods that can design the right operating conditions. Along this line, a new facile approach to design thermally safe operating conditions for isoperibolic homogeneous SBRs has been developed in this article. This approach is developed on the basis of deep insights into the phenomenon that the MTSR vs reaction temperature profiles for isothermal exothermic reactions present an "S" shape. The approach has been experimentally validated using the hydrolysis reaction of acetic anhydride. However, more work should be carried out to extend this method to more complex reaction systems, like consecutive reactions.

Safety Criteria for Solid–Liquid Heterogeneous Systems in Semibatch Reactors

“…A comparison of the elaborated safety diagram and temperature diagram to other criteria is shown in Table 1 . The criteria of divergence and Morbidelli–Varma were compared with the safety boundary diagram by Westerterp et al 13 The result showed that the divergence criterion is too conservative, indicating a higher T cool as a critical temperature. The results of the Morbidelli–Varma criterion and the safety diagram were well-matched.…”

Kinetic-Parameter-Free Approach To Design Thermally Safe and Productive Operating Conditions for Isoperibolic Liquid–Liquid Semibatch Reactors

“…This is because it is difficult to decide whether the reactants are completely consumed only by reaction calorimetry tests. In our previous work, 30 a solution to this problem has been proposed. In the following, we briefly introduce this solution.…”

A Kinetics-Free Approach To Safely and Productively Scale Up Isoperibolic Homogeneous Semibatch Reactors

“…According to our previous work, 12 when the dosing period (t D ) is 3800 s and the T j = 90 °C in the laboratory reactor, the corresponding isoperibolic operations must be perofrmed in the QFS region. However, the value of MTSR is experimentally determined to be higher than 117.9 °C.…”

“…Since the goal of this work is to develop a kinetics-free approach to scale up isoperibolic SBRs, the method to determine QFS operation conditions in the laboratory reactor should also be kinetics-free. In our previous work, , a kinetics-free approach to design QFS operations in SBRs has been developed on the basis of the fact that, as long as the MTSR values increase with the reaction temperature under isothermal operation, the corresponding isoperibolic homogeneous SBRs must be in the QFS situation, regardless of the values of Wt .…”

“…Generally, before the operating conditions of isoperibolic SBRs are scaled up to the industrial scale, the safe operating conditions should first be designed in the laboratory reactors. In the last several decades, many works have been devoted to this research area. − Most of the works require knowledge of the reaction kinetics, at least the apparent kinetics. − This significantly restricts the process of designing safe operating conditions, since determination of accurate kinetic parameters is really a time-consuming process in the fine chemicals industry . From this line, many works have been devoted to develop kinetics-free (at least kinetics-parameter-free) approaches. − …”