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: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.
Dibenzoyl peroxide (BPO) has been widely employed in the petrifaction industry. This study determined the unsafe characteristics of organic peroxide mixed with incompatible materials so as to help prevent runaway reactions, fires or explosions in the process environment. Thermal activity monitor III (TAM III) was applied to assess the kinetic parameters, such as kinetic model, reaction order, heat of reaction (ΔHd), activation energy (Ea), and pre-exponential factor (k0), etc. Meanwhile, TAM III was used to analyze the thermokinetic parameters and safety indices of BPO and contaminated with sulfuric acid (H2SO4) and sodium hydroxide (NaOH). Simulations of a 0.5 L Dewar vessel and 25 kg commercial package in green thermal analysis technology were performed and compared to the thermal stability. From these, the optimal conditions were determined to avoid violent reactions in incompatible materials that cause runaway reactions in storage, transportation, and manufacturing.
Authors:Y. Chen, Y. Chou, H. Hou, Y. I, and C. Shu
Organic peroxides (OPs) are very susceptible to thermal sources, chemical pollutants or even mechanical shock. Over the years,
they have caused many serious explosions. Cumene hydroperoxide (CHP) is widely employed to produce phenol and dicumyl peroxide
(DCPO) in the manufacturing process. Differential scanning calorimetry (DSC) and thermal activity monitor (TAM) were employed
to determine the potential thermal hazards and thermokinetic parameters (such as exothermic onset temperature (T0), maximum temperature (Tmax), and enthalpy (ΔH)) of CHP mixed with sodium hydroxide (NaOH) and sulfuric acid (H2SO4). High performance liquid chromatography (HPLC) was used to analyze the concentration vs. time of CHP.When CHP is mixed with NaOH, the T0 is induced earlier and reactions become more intricate than the pure CHP solution. CHP added to NaOH or H2SO4 is more dangerous than pure CHP alone. Depending on the operating conditions, NaOH and H2SO4 are the incompatible chemicals for CHP.
Investigations of nitrogen content and thermal decomposition activation energy (Ea) of two different kinds of nitrocellulose (NC) products, NMNC and MNC from the non-fat and original processes of linters,
respectively, were discussed. In this study, differential scanning calorimetry (DSC) and element analyzer (EA) are used, for
the above two chemicals, along with the same nitration condition in use of sulfuric acid (H2SO4) and nitric acid (HNO3) mixing acid. Ea was calculated by our induced model. According to our experimental results, the nitrogen content of NMNC/MNC was 11.71 and
11.55 mass%, in a low nitrogen content condition of mixing acid. The Ea parameters were 319.91 (NMNC) and 347.27 (MNC) kJ mol−1, individually. They indicated that the non-fat process of a linter made a higher degree of stability than the others. This
research also presents an efficient and accurate model of the thermal decomposition property evaluation for non-fat process
of linters. The outcome is believed to be very useful for helping to understand, and be applied as, an inherently safer design
during relevant NC manufacturing processes.
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:Y.-P. Chou, H.-Y. Hou, R.-H. Chang, M.-L. You, J.-Y. Peng, and C.-M. Shu
Cumene hydroperoxide (CHP) and its derivatives have caused many serious explosions and fires in Taiwan as a consequence of
thermal instability, chemical contamination, and even mechanical shock. It has been employed in polymerization for producing
phenol and dicumyl peroxide (DCPO). Differential scanning calorimetry (DSC) was used to analyze the thermal hazard of CHP
in the presence of sodium hydroxide (NaOH), sulfuric acid (H2SO4), and sodium bisulfite (Na2SO3). Thermokinetic parameters for decomposition, such as exothermic onset temperature (T0), maximum temperature (Tmax), and enthalpy (ΔH), were obtained from the thermal curves. Isothermal microcalorimetry (thermal activity monitor, TAM) was employed to investigate
the thermal hazards during CHP storage and CHP mixed with NaOH, H2SO4, and Na2SO3 under isothermal conditions in a reactor or container. Tests by TAM indicated that from 70 to 90 °C an autocatalytic reaction
was apparent in the thermal curves. According to the results from the TAM test, high performance liquid chromatography (HPLC)
was, in turn, adopted to analyze the result of concentration versus time. By the Arrhenius equation, the activation energy
(Ea) and rate constant (k) were calculated. Depending on the process conditions, NaOH was one of the incompatible chemicals or catalysts for CHP. When
CHP is mixed with NaOH, the T0 is induced earlier and the reactions become more complex than for pure CHP, and the Ea is lower than for pure CHP.
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:Wan-Cheng Tan, Radzali Othman, Akihiko Matsumoto, and Fei-Yee Yeoh
Empty fruit bunch fibre was obtained from a local palm oil mill in Penang, Malaysia, while sulphuricacid (H2SO4 ) was purchased from Merck for ACF synthesis. Dried, cleaned EFB fibre was treated with concentrated H 2 SO 4 . For carbonisation, the H 2
Authors:Hung-Cheng Chou, Sheng-Hung Wu, Chung-Cheng Chiang, Jao-Jia Horng, Jen-Hao Chi, and Chi-Min Shu
% CHP was used to produce phenol and acetone by 2,000 ppm of sulfuricacid (H2SO4 ) in the traditional process. H 2 SO 4 mixed with 80 mass% CHP can increase heat of decomposition (Δ H d ) and the temperature of reaction. Cooling system failures have