Authors:Mei-Li You, Ming-Yang Liu, Sheng-Hung Wu, Jen-Hao Chi, and Chi-Min Shu
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.
Authors:Sheng-Hung Wu, Meng-Lung Lin, and Chi-Min Shu
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 (T0), heat of decomposition (ΔHd), temperature rise rate (dT · dt−1), time to maximum rate under adiabatic situation (TMRad), pressure rise rate (dP · dt−1), and maximum pressure (Pmax), etc. The T0 was calculated to be 130 °C using DSC and VSP2. Activation energy (Ea) 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.
Authors:Mei-Li You, Jo-Ming Tseng, Ming-Yang Liu, and Chi-Min Shu
Pooling lauroyl peroxide (LPO) with nitric acid, we used differential scanning calorimetry (DSC) to assess the thermokinetic
parameters, such as exothermic onset temperature (T0), heat of decomposition (ΔHd), 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
Authors:C. Chang, Y. Chou, J. Tseng, M. Liu, and C. Shu
Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics
regarding stability would represent potential hazards during the production or utilization stage and could be determined by
calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate
the thermokinetic parameters for MWNTs at various compositions.
Thermoanalytical curves showed that the average heat of decomposition (ΔHd) of the MWNTs samples in a manufacturing process was about 31,723 J g−1, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence
of sulfuric acid (H2SO4). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch
addition with reactants of H2SO4. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation
Authors:Sun-Ju Shen, Sheng-Hung Wu, Jen-Hao Chi, Yih-Wen Wang, and Chi-Min Shu
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
(ΔHd) and exothermic onset temperature (T0), 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, T0, heat of decomposition (ΔHd), and activation energy (Ea) of DCPO mixed with HNO3 were calculated to be 70 °C, 911 J g−1, and 33 kJ mol−1, respectively.
Authors:J.-J. Peng, S.-H. Wu, H.-Y. Hou, C.-P. Lin, and C.-M. Shu
Over 90% of the cumene hydroperoxide (CHP) produced in the world is applied in the production of phenol and acetone. The additional
applications were used as a catalyst, a curing agent, and as an initiator for polymerization. Many previous studies from open
literature have verified and employed various aspects of the thermal decomposition and thermokinetics of CHP reactions. An
isothermal microcalorimeter (thermal activity monitor III, TAM III), and a thermal dynamic calorimetry (differential scanning
calorimetry, DSC) were used to resolve the exothermic behaviors, such as exothermic onset temperature (T0), heat power, heat of decomposition (ΔHd), self-heating rate, peak temperature of reaction system, time to maximum rate (TMR), etc. Furthermore, Fourier transform
infrared (FT-IR) spectrometry was used to analyze the CHP products with its derivatives at 150 °C. This study will assess
and validate the thermal hazards of CHP and incompatible reactions of CHP mixed with its derivatives, such as acetonphenone
(AP), and dimethylphenyl carbinol (DMPC), that are essential to process safety design.
Authors:L. Wu, K. Chen, S. Cheng, B. Lee, and C. Shu
Hydrogen peroxide (H2O2) is popularly employed as a reaction reagent in cleaning processes for the chemical industry and semiconductor plants. By
using differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2), this study focused on the thermal decomposition
reaction of H2O2 mixed with sulfuric acid (H2SO4) with low (0.1, 0.5 and 1.0 N), and high concentrations of 96 mass%, respectively. Thermokinetic data, such as exothermic
onset temperature (T0), heat of decomposition (ΔHd), pressure rise rate (dP/dt), and self-heating rate (dT/dt), were obtained and assessed by the DSC and VSP2 experiments. From the thermal decomposition reaction on various concentrations
of H2SO4, the experimental data of T0, ΔH, dP/dt, and dT/dt were obtained. Comparisons of the reactivity for H2O2 and H2O2 mixed with H2SO4 (lower and higher concentrations) were evaluated to corroborate the decomposition reaction in these systems.
Authors:Sheng-Hung Wu, Hung-Cheng Chou, Ryh-Nan Pan, Yi-Hao Huang, Jao-Jia Horng, Jen-Hao Chi, and Chi-Min Shu
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 (ΔHd), exothermic onset temperature (T0), self-accelerating decomposition temperature (SADT), time to maximum rate (TMR), critical temperature (Tc), 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, Tc, etc. In view of loss prevention, more useful indicators must be provided in the sheets or guide book.
Authors:R. Lee, H. Hou, J. Tseng, M. Chang, and C. Shu
Organic peroxides are commonly employed as an initiator for polymerization, a source of free radicals, a hardener, and a linking
agent. Due to its relatively weak oxygen-oxygen bond, di-tert butyl peroxide (DTBP) has been categorized as flammable type or Class III by the National Fire Protection Association (NFPA).
The transport of dangerous goods (TDG) has published a warning against DTBP that it could potentially induce violent heat,
explosion, fire and self-ignition under certain circumstances.
DTBP has been recommended as an international standard sample for estimating the performance of several calorimeters, such
as glass tube tests, differential scanning calorimetry (DSC), and vent sizing package 2 (VSP2). In this study, we measured
the precise temperature changes and heat flow with the above-mentioned testing instruments. However, some runaway incidents
caused by DTBP have demonstrated the reaction temperature could be as low as ambient temperature. The reactivity and the hazardous
incompatibility with sulfuric acid (H2SO4) and hydrochloric acid (HCl) of DTBP have not been evident, and the runaway hazards involved in different processing conditions
were clarified in this study by implementing the two calorimeters. Acid-catalyzed characteristics and reaction hazards of
DTBP could be acquired, such as heat of decomposition (ΔHd) and exothermic onset temperature (T0).
Authors:Lung-Chang Tsai, Jyun-Wei Chen, Hung-Yi Hou, Shang-Hao Liu, and Chi-Min Shu
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 (T0), maximum heat-releasing peak (Tmax), and heat of decomposition (ΔHd). 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.