Safe operation of stirred‐tank semibatch reactors subject to risk of thermal hazard

Abstract

In this work, the behavior of exothermic chemical reactions conducted in a wall-cooled, semibatch stirred-tank reactor is studied, with particular attention to conditions that lead to a thermal accident. The dimensionless heat and mass conservation equations for a semicontinuous tank were solved using second-order irreversible kinetics and a number of selected dimensionless numbers, for both the feed period and the late batch stage. The criterion implemented is based on the nonaccumulation of the dosed reactant, and the safest operating mode is based on the values of the reactor parameters that lead to an instantaneous consumption of the dosed feed. The criterion is implemented into an algorithm that runs in parallel with the integration of the model equations. Its applicability is shown using a few examples that show that the computer implementation of our methods works well in hazard prediction.

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

“…In the last decades, many works have been published to design thermally safe operating conditions for isoperibolic SBRs. − Most of these works require detailed reaction kinetics, at least the apparent kinetics. However, determination of the kinetic models and parameters is time-consuming and money-consuming in realistic cases.…”

Synthesis of 4-Chloro-3-nitrobenzotrifluoride: Industrial thermal runaway simulation due to cooling system failure

“…Runaway phenomena in chemical reactors have been thoroughly analyzed in the process safety literature of the last twenty five years (e.g., Steensma and Westerterp, 1988;Balakotaiah et al, 1995;Alós et al, 1998;van Woezik and Westerterp, 2000;Zaldívar et al, 2003;Bosch et al, 2004;Varma et al, 2005;Mas et al, 2006;Maestri et al, 2009a;Copelli et al, 2011a,b;Jiang et al, 2011;Maria and Stefan, 2011;Casson et al, 2012), even performing full-scale experimental tests (Linga et al, 2013). It is well known that a runaway reaction is the consequence of a reacting system thermal loss of control that can be triggered by a number of upset operating conditions: e.g., pumps failure, cooling system breakdown, temperature controller anomalies or external fire.…”