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- Author or Editor: Chi-Min Shu x
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Abstract
Tert-butyl peroxide (TBPO), is a typical organic peroxides (OPs), which is widely applied as initiator in poly-glycidyl methacrylate (PGMA) reaction, and is employed to provide a free-radical in frontal polymerization, and which has also caused many thermal runaway reactions and explosions worldwide. To find an unknown and insufficient hazard information for an energetic material, differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2) were employed to detect the fundamental thermokinetic parameters involving the exothermic onset temperature (T 0), heat of decomposition (ΔH d), temperature rise rate (dT · dt −1), time to maximum rate under adiabatic situation (TMRad), pressure rise rate (dP · dt −1), and maximum pressure (P max), etc. The T 0 was calculated to be 130 °C using DSC and VSP2. Activation energy (E a) of TBPO was evaluated to be 136 kJ mol−1 by VSP2. In view of the loss prevention, calorimetric applications and model evaluation to integrate thermal hazard development are adequate means for inherently safer design.
Abstract
The thermokinetic parameters were investigated for cumene hydroperoxide (CHP), di-tert-butyl peroxide (DTBP), and tert-butyl peroxybenzoate (TBPB) by non-isothermal kinetic model and isothermal kinetic model by differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III), respectively. The objective was to investigate the activation energy (E a) of CHP, DTBP, and TBPB applied non-isothermal well-known kinetic equation to evaluate the thermokinetic parameters by DSC. We employed TAM III to assess the thermokinetic parameters of three liquid organic peroxides, obtained thermal runaway data, and then used the Arrhenius plot to obtain the E a of liquid organic peroxides at various isothermal temperatures. In contrast, the results of non-isothermal kinetic algorithm and isothermal kinetic algorithm were acquired from a highly accurate procedure for receiving information on thermal decomposition characteristics and reaction hazard.
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.
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.
Abstract
A hierarchical set of kinetic models were proposed and discussed for simulation of autocatalytic decomposition of cumene hydroperoxide (CHP) in cumene at low temperatures. The hierarchy leads from a formal model of full autocatalysis, which is based on conversion degree as a state variable, through a two-stage autocatalytic concentration-based model to a meticulous multi-stage model of the reaction. By the ForK (Formal Kinetics) and DesK (Descriptive Kinetics) software, developed by ChemInform Saint Petersburg (CISP) Ltd., the related kinetic parameters and their significance have also been estimated and elucidated. Through this best-fit approach, it is possible to formulate a systematic methodology on the kinetic studies for thermal decomposition of typical organic peroxides with autocatalytic nature, specifically at low temperature ranges.
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.
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.
Abstract
When above certain temperature limits, lauroyl peroxide is an unstable material. If the thermal source cannot be properly governed during any stage in the preparation, manufacturing process, storage or transport, runaway reactions may inevitably be induced immediately. In this study, the influence of runaway reactions on its basic thermal characteristic was assessed by evaluating thermokinetic parameters, such as activation energy (E a) and frequency factor (A) by thermal activity monitor III (TAM III). This was achieved under five isothermal conditions of 50, 60, 70, 80, and 90 °C. Vent sizing package 2 (VSP2) was employed to determine the maximum pressure (P max), maximum temperature (T max ), maximum self-heating rate ((dT dt −1)max), maximum pressure rise rate ((dP dt −1)max), and isothermal time to maximum rate ((TMR)iso) under the worst case. Results of this study will be provided to relevant plants for adopting best practices in emergency response or accident control.
Abstract
The decomposition of organic peroxides by their relatively weak oxygen linkage and hydroperoxide radical in the presence of reaction solution is one of the thermal hazards for triggering a runaway reaction. Runaway incidents may occur in oxidation reactors, vacuum condensation reactors, tank lorries, or storage tanks. In NFPA 432 organic peroxides in NFPA 432 are classified as flammable. The exothermic behaviors of solid organic peroxides, dicumene peroxide, benzoyl peroxide, and lauroyl peroxide, were determined by differential scanning calorimetry (DSC), and vent sizing package 2 (VSP2). Relevant data detected by DSC provided thermal stability information, such as exothermic onset temperature (T 0), maximum heat-releasing peak (T max), and heat of decomposition (ΔH d). VSP2 was used to perform the bench scale situation for pushing the expected or unexpected reaction to undergo runaway reaction. Onset temperature, maximum pressure, self-heating rate ((dT dt −1)max), and pressure-release rate ((dP dt −1)max) were therefore obtained and explained. These results are essentially crucial in process design for an inherently safer approach.
Abstract
Pooling lauroyl peroxide (LPO) with nitric acid, we used differential scanning calorimetry (DSC) to assess the thermokinetic parameters, such as exothermic onset temperature (T 0), heat of decomposition (ΔH d), frequency factor (A), and the other safety parameters. When LPO was contaminated with nitric acid (HNO3), we found the exploder 1-nitrododecane. Obvious products were sensitive and hazardous chemicals. Concentration reaching 1–12 N HNO3 emitted a large amount of heat. This study combined with curve-fitting method to elucidate its unsafe characteristics and thermally sensitive structure to help prevent runaway reactions, fires and explosions in the process environment. According to the findings and the concept of inherently safer design, LPO runaway reactions could be adequately prevented in the relevant plants.
