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Abstract  

Lauroyl peroxide (LPO) is a typical organic peroxide that has caused many thermal runaway reactions and explosions. Differential scanning calorimetry (DSC) was employed to determine the fundamental thermokinetic parameters that involved exothermic onset temperature (T0), heat of decomposition (ΔHd), and other safety parameters for loss prevention of runaway reactions and thermal explosions. Frequency factor (A) and activation energy (Ea) were calculated by Kissinger model, Ozawa equation, and thermal safety software (TSS) series via DSC experimental data. Liquid thermal explosion (LTE) by TSS was employed to simulate the thermal explosion development for various types of storage tank. In view of loss prevention, calorimetric application and model analysis to integrate thermal hazard development were necessary and useful for inherently safer design.

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Abstract  

Dicumyl peroxide (DCPO) is usually employed as an initiator for polymerization, a source of free radicals, a hardener, and a linking agent. In Asia, due to its unstable reactive nature, DCPO has caused many thermal explosions and runaway reaction incidents in the manufacturing process. This study was conducted to elucidate its essentially thermal hazard characteristics. In order to analyze the runaway behavior of DCPO in a batch reactor, thermokinetic parameters, such as heat of decomposition (ΔH d) and exothermic onset temperature (T 0), were measured via differential scanning calorimetry (DSC). Thermal runaway phenomena were then thoroughly investigated by DSC. The thermokinetics of DCPO mixed with acids or bases were determined by DSC, and the experimental data were compared with kinetics-based curve fitting of thermal safety software (TSS). Solid thermal explosion (STE) and liquid thermal explosion (LTE) simulations of TSS were applied to determine the fundamental thermal explosion behavior in large tanks or drums. Results from curve fitting indicated that all of the acids or bases could induce exothermic reactions at even an earlier stage of the experiments. In order to diminish the extent of hazard, hazard information must be provided to the manufacturing process. Thermal hazard of DCPO mixed with nitric acid (HNO3) was more dangerous than with other acids including sulfuric acid (H2SO4), phosphoric acid (H3PO4), and hydrochloric acid (HCl). By DSC, T 0, heat of decomposition (ΔH d), and activation energy (E a) of DCPO mixed with HNO3 were calculated to be 70 °C, 911 J g−1, and 33 kJ mol−1, respectively.

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Abstract  

Hydrogen peroxide (H2O2), historically, due to its broad applications in the chemical industries, has caused many serious fires and explosions worldwide. Its thermal hazards may also be incurred by an incompatible reaction with other chemical materials, and a runaway reaction may be induced in the last stage. This study applied thermal analytical methods to explore the H2O2 leading to thermal accidents by incompatibility and to discuss what might be formed by the upset situations. In this study, the thermal hazard analyses were conducted with various solvents, propanone (CH3COCH3), Fe2O3, FeSO4, H2SO4, HCl, HNO3, H3PO4, NaOH, LiOH, and KOH which were deliberately selected to individually mix with H2O2 for investigating the degree of hazard. Differential scanning calorimetry (DSC) was employed to evaluate the thermal hazard of H2O2-mixed ten chemicals. The results indicated that H2O2 is highly hazardous while separately mixed with ten materials, as a potential contaminant. Fire and explosion hazards could be successfully reduced if the safety-related data are suitably imbedded into manufacturing processes.

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Abstract

Oxygen (O2) or air is widely applied globally to yield cumene hydroperoxide (CHP) in a cumene oxidation tower. In previous studies, CHP has been identified as a thermally hazardous chemical. This study was used to evaluate thermal hazard of CHP in cumene using differential scanning calorimetry and vent sizing package 2 (VSP2). Self-accelerating decomposition temperature (SADT), self-heating rate, exothermic onset temperature (T 0), critical temperature (T c), time to maximum rate (TMR), activation energy (E a), etc., were employed to prevent and protect thermal runaway reaction and explosion in the manufacturing process and/or storage area. The reaction order (n) of CHP was evaluated to be 0.5 in this study. The E a was determined to be 122 kJ mol−1 by VSP2. High volume of CHP with 0 rpm of stirring rate by VSP2 was more dangerous than a low one. Control of stirring rate should be a concern in process safety management program. In view of proactive loss prevention, inherently safer handling procedures and storage situations should be maintained in the chemical industries.

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Journal of Thermal Analysis and Calorimetry
Authors: Sheng-Hung Wu, Hung-Cheng Chou, Ryh-Nan Pan, Yi-Hao Huang, Jao-Jia Horng, Jen-Hao Chi, and Chi-Min Shu

Abstract

Organic peroxides (OPs) and inorganic peroxides (IPs) are usually employed as an initiator for polymerization, a source of free radicals, a hardener, and a linking agent in low density polyethylene (LDPE), polyvinyl chloride (PVC), controlled-rheology polypropylene (CR-PP), and styrene industries. Worldwide, due to their unstably reactive natures, OPs and IPs have caused many serious thermal explosions and runaway reaction incidents. This study was conducted to elucidate its essentially hazardous characteristics. To analyze the runaway behavior of OPs and IPs in the traditional process, thermokinetic parameters including heat of decomposition (ΔH d), exothermic onset temperature (T 0), self-accelerating decomposition temperature (SADT), time to maximum rate (TMR), critical temperature (T c), etc., were measured by calorimetric approaches involving differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and calculation method. Safety and health handling information of hazardous materials and toxic substances is noted in material safety data sheets (MSDS) and was applied to analyze in process safety management (PSM) in the chemical industries, but MSDS are not providing important handling indicators concerning the SADT, TMR, T c, etc. In view of loss prevention, more useful indicators must be provided in the sheets or guide book.

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