Determining the Safe Operating Conditions for Gas-Liquid Heterogeneous Reactions in an Isochoric Semi-Batch Reactor

In semi-batch reactors (SBRs), exothermic reactions can still result in thermal runaway accidents due to improper process conditions. Mass transfer processes as well as the dissolution heat make the thermal behavior of gas-liquid reactions more variable. This study aims to propose safety criteria for gas-liquid reactions in SBRs. A dimensionless mathematical model of the gas-liquid reaction in SBRs was firstly established to determine the thermal runaway critical conditions by considering the mass transfer process. The safety boundary diagram and temperature diagram applicable for the gas-liquid reaction were constructed, along with a procedure for determining safe operating conditions for gas-liquid reactions in SBRs. The mass transfer coefficient, Henry’s constant and the dissolution heat all have a great influence on the thermal behavior of the reactions. A series of calorimetry experiments were carried out for the reaction between carbon dioxide and aqueous ammonia solution using RC1 to determine critical operating conditions.