A general kinetic model framework for the interpretation of adiabatic calorimeter rate data

Notwithstanding the variety and complexity of the reactions studied by adiabatic calorimeters like ARC, the data interpretation techniques are not general enough. Traditional thermokinetic analysis primarily lumps a complex multi-step reaction into a single overall reaction and ignores possible thermal effects in some of the possible side reactions. With detailed chromatographic/mass spectrometric analysis of the headspace gases and the condensed phase residues, the pressure profile becomes an additional source of identification of the mechanism and the kinetics of the overall reaction. Finally, in the context of new multiphase catalytic processes of greater efficiency and environment friendliness and with reference to the storage of potentially incompatible fluid mixtures in metallic containers, ARC studies of heterogeneous reaction systems are becoming part of the mandatory safety evaluations. With a few additional measurements a proper kinetic interpretation of the ARC data on such systems seems possible. The paper presents a general model that was shown to be easily adaptable to a number of published reactions of various complexities referred to above. Standard thermal hazard characteristics like the onset temperature, adiabatic temperature rise, self-heat rate, time-to-maximum rate, pressure-temperature profile, etc. could be accurately calculated by the model and these compared closely with the experimental data. It is hoped that the model would be useful as a general-purpose tool for the interpretation of adiabatic calorimetric data for the purpose of process hazard assessment.