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Azo compounds (azos) are vital basic initiators used in chemical plants that also possess thermally active properties. Azos may trigger serious accidents because of their intense exothermicity. We applied a specific method to characterize the reaction kinetics of azos using data from differential scanning calorimetry (DSC). Specifically, this method was used to analyse the thermal decomposition of 2,2-azobis(2-methylbutyronitrile) (AMBN). The exothermic peak temperature, exothermic final temperature, and heat of decomposition were determined. The data obtained from the experiments were utilized to predict the self-accelerating decomposition temperature, control temperature, and emergency temperature. Experiments conducted to explore the runaway phenomenon of AMBN during the overall decomposition process interfered with the thermal analysis studies. We utilized a process simulation model to mimic the decomposition of AMBN, ensuring that the simulation results were realistic and practical. The results are worthy of being applied to thermal analysis, for example, for application in proactive loss prevention.

The reaction of propylene with adsorbents such as BASF selexsorb CD and UOP of various sizes was studied. Adiabatic runaway tests were conducted on propylene mixed with various adsorbents to obtain knowledge on the thermal profile of each. Thermokinetic data were obtained from non-isothermal calorimetric study from the oligomerized reaction between propylene and various adsorbents. A detailed distribution of sorbent product from the adsorber has been analyzed for carbon product greater than 6 ( >C 6 ) using gas chromatography/mass spectrometry results. The test revealed oligomerization and carbonaceous deposit formation of the adsorbent products. The reason for over-temperature of the reactor wall can be anticipated from the agglomeration of carbonaceous deposit disrupting the normal flow of propylene stream causing channeling and lowering the carry-away of heat-accumulated. This approach of real conditions, along with the simulation of process design and operation using computational fluid dynamics (CFD) studies, can render safer process information for avoiding the occurrence of similar runaway explosion induced industrial disaster.

O,O-dimethylphosphoramidothioate (DMPAT) is widely used as the vital intermediate in pesticides to synthesize acephate, chlorine methamidophos, and methamidophos. February, 2016, a serious explosion and fire occurred in Taichung, Taiwan, resulting from DMPAT decomposition, causing one death and injuring one employee. To explore the thermal hazard of DMPAT, we applied various instruments of thermal analysis. Combustion phenomena and decomposed products were identified by combustion test and gas chromatography-mass spectrometry. Differential scanning calorimetry and thermogravimetry were used to analyze the thermal stability parameters, and mass loss conditions under five heating rates illustrating decomposition. Vent sizing package 2 was used to simulate stirring or unstirring system failure in a practical process. The apparent activation energy of DMPAT and self-accelerating decomposition temperature were, respectively, 92.4 ± 3.2 kJ/mol calculated by Starink equation, and 66.0 °C by simulated approach. The findings of these results are vital for inherently safer measures during production, storage, and transportation.

A new approach was used to monitor the autocatalytic reaction of benzoyl peroxide (BPO) by non-isothermal and isothermal kinetic models constructed using differential scanning calorimetry and thermal activity monitor III analyses, respectively. Autocatalytic reactions generally start slowly and then accelerate as the reactant is consumed and the autocatalyst is produced. Consequently, an autocatalytic reaction may require special design considerations to avoid certain upset conditions, such as runaway exothermic reactions. We conducted a thermal hazard analysis of various products, including benzoic acid, benzene, and phenol, which were deliberately selected and individually mixed with BPO to investigate their thermal hazards. Model fitting can be applied to predict the amount of time required to achieve the maximum rate under isothermal conditions at any temperature of interest. The proposed procedure was effective and accurate for evaluating the autocatalytic reaction of BPO.

Organic peroxides (OPs) are commonly used in many industrial fields as initiators, hardeners, or cross-linking agents of radical polymerization with unsaturated monomers. However, OPs contain the bivalent O O structure which can incur exothermic decomposition that involves the splitting of the peroxide bond with a huge heat release and gas products that may cause an explosion under an uncontrollable upset. Differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III) were used to analyze the thermal hazards and incompatibilities (H2SO4, NaOH, and Na2SO3) of cumene hydroperoxide (CHP), benzoyl peroxide (BPO), and dicumyl peroxide (DCPO). Dynamic and isothermal scanning tests were performed to compare the exothermic behaviors in a process. The thermokinetic data obtained via vent sizing package 2 (VSP2) were applied for evaluation, and the effects of thermal runaway hazard were compared for OPs conducted by acids and alkalis. These results are critically important in safer process design for producing and using OPs.