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In Taiwan, due to intensive religious ceremonial activities, the flying and pyrotechnic fireworks of firecrackers are commonly used. In the course of the activities, the use of water as a cooling measure has been pointed out in the past literature that it may cause pyrotechnic materials to deteriorate and reduce their thermal stability. To determine the possible influence of water addition on pyrotechnic deterioration, this study estimates the degree of thermal hazard of pyrotechnic based on the analysis of heat release, reaction kinetics, and the heat exchange model of pyrotechnic deterioration. The explosion sound (ES) firecracker was used to analyze the thermal hazard and mixed water (ES + W) to simulate the dampness condition using differential scanning calorimetry. Thermodynamic equations simulating thermal hazard safety parameters, combined with thermokinetic and thermal runaway data results, were used to discuss the safety and potential thermal hazard characteristics of ES, as the safety of fireworks in storage, transportation, process conditions, and operation assessment to curtail the probability of accidents. The results showed that if the initial exothermic temperature of ES + W is higher than ES, a thermal decomposition reaction will occur at a lower temperature, and the exothermic heat rises and the apparent activation energy decreases, indicating that the ES will increase its instability after being damp. The presence of water degenerated the ES and resulted in a violent reaction during the release process to explode the ES, which increased the chance of accidents among the onlookers.

External short circuit has a severe influence on lithium battery’s performance. Currently, a huge study has focused on the single battery’s short circuit. However, cells are often interconnected into a module in real applications. There are many possibilities that external short circuit of a single cell has huge impact on the other cells in a battery module. In this research, experiments were conducted under different conditions (single lithium-ion battery, 3 lithium-ion battery modules, 9 lithium-ion battery modules) at different ambient temperatures (30, 40, and 50 °C) and different state of charge [SOCs (80%, 90%, 100%)] The temperature of the battery surface (positive electrode, middle) rose during external short circuit. The variation of the battery temperature was analyzed. Then, the variation of battery performance parameters under external short circuit conditions was studied. All lithium-ion batteries were divided into two groups, one being an external short circuit and the other being not short-circuited externally. As a result, when the lithium-ion battery was short-circuited externally, the battery temperature rose rapidly to the maximum temperature that the battery can rise. The highest temperature caused by external short circuit appeared in the case of a single battery. The higher the SOC, the faster the battery temperature rose. In the cycle charge and discharge, the rate of decay of the battery after an external short circuit was twice faster than that of a normal battery. As the temperature increased, the rate of battery capacity decayed further. Under normal circumstances, the attenuation of the battery to 80% required about 350 cycles. The life of the battery after the external short circuit was shortened by more than half, and when the temperature rises, even only about 100 cycles were required.

Heat generation and accumulation during working schemes of the lithium-ion battery (LIB) are the critical safety issues in hybrid electric vehicles or electric vehicles. Appropriate battery thermal management is necessary for ensuring the safety and continuous power supply of rechargeable LIB modules. In this study, thirty cylinder 18650-type cells were fabricated a 6S5P battery module with a 2-mm spacing between cells to evaluate exothermic trajectories. The modules, equipped with a forced-air cooling system, were charged at 1 C-rate and discharged at 1, 1.5, and 2 C-rates for three cycles in each test; thermocouples were connected to the cells to track the variances in temperature and voltage. The efficiency of the developed forced-air cooling system was estimated to be 73.0% in case 1 with the 1 C discharge rate, and the temperature difference (TD) was less than 5.0 °C. The maximum temperature (Tmax) of this case was maintained below 45.0 °C showing uniform heat distribution. Moreover, extreme heat accumulation developed inside the module and damaged the adjacent LIBs during fast 2 C discharge test. Our TD testing showed that a forced-air cooling system in the LIB module provides effective heat dispersion under normal discharge conditions.

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.

In Taiwan, on July 30, 2011, a huge explosion occurred at a propylene purification unit when eliminating impurities such as H2O, H2S, and COS. This incident severely eroded public faith in mechanisms for ensuring chemical process safety. Plant operators failed to identify the serious situation; this failure has been blamed on their use of insufficient detection equipment and inaccurate data. In this study, we demonstrated a relationship between propylene and the thermal characteristics of the sorbents used. To reconstruct the accident, reaction pathway analysis, pseudo-adiabatic adsorption conditions, and precise thermal parameters were modelled using vent sizing package 2, a pseudo-adiabatic calorimeter. For an in-depth analysis, computational fluid dynamics (CFD) modelling techniques were employed. The results indicated that propylene adsorption immediately raised the sorbent bed temperature. Severe oligomerisation was identified upon the temperature reaching 150 °C; this was suspected to be the main reason for the thermal chain reaction and its effects. Moreover, gaseous-phase propylene diminished the heat-removal capacity during the process. This led to considerable adsorption heat, causing a chain reaction that resulted in the explosion and fire. CFD results showed that shortening the liquefaction period was effective for operation safety. Finally, the unavoidable adsorption heat release acted as the initiator, triggering the advanced reaction in a nonrigorous system. In this study, practicable numerical methods were expanded to predict the runaway reaction of the adsorbent system, and the results revealed blind spots in the system data with respect to the accident scenario.

In a Taiwanese chemical processing plant producing ethylbenzene, an unexpected thermal runaway reaction occurred in an alkylation tower during shutdown, causing approximately 7500 kg of catalyst to be wasted. Prior risk assessments failed to identify the responsible hazard vectors. The thermal runaway occurred despite all former appropriate operating procedures being strictly followed. To identify the root cause of this incident, the generation and dissemination of the thermal source were tested and simulated using thermal analysis methods and a prototype tower. The results showed that water adsorption could provide heat to the catalyst bed, even at temperatures exceeding 350 °C, which is the temperature required for the oxidation of hydrocarbon adsorbates. High humidity caused by Typhoon Lionrock was a critical factor contributing to the incident, which was not anticipated by the plant engineers. Humidity within the air inlet supplied the abundant adsorption heat required to increase the bed temperature. This resulted in thermal runaway due to heavy oxidation of the large number of adsorbates. This study proposes a safer strategy that involves passing humid N2 through the catalyst tower to prevent the oxidation of hydrocarbon adsorbates, thereby removing the adsorption heat. The purpose of this study was to reveal hazards concealed in the catalyst system. If a catalyst has a noticeable adsorption heat that, at a given temperature, can induce spontaneous oxidation or decomposition of the adsorbates with a possible thermal runaway reaction. This paper interprets past failures as lessons and proposes solutions that can be used by those in the chemical manufacturing industry to avert such incidents in the future.

Hazards due to spontaneous combustion of coal seriously threaten coal mining safety. To explore and evaluate the prediction indices and limiting parameters of coal self-ignition, seven samples from the Huainan mining area in Anhui Province, China were tested. Experiments were conducted using an oil-bath temperature-programmed system. The experimental results indicated that the oxygen consumption rates and CO production increased slowly initially and then rapidly with the increase in temperature. The plots of CO/CO2 ratio versus temperature exhibited an exponential property. The C2H4/C2H6 ratios exhibited an unstable alternation when the temperature was in the range of 100–130 °C. However, the ratios became steady after the temperature increased above 130 °C. The low-temperature oxidation process was divided into three stages according to the Δ C CO / Δ C O 2 ratios. The oxidation index DO, a new indicator, was used to precisely forecast the point of spontaneous combustion. The limiting parameter analysis indicated that the minimum float coal thicknesses hmin and limiting oxygen concentrations Cmin first increased and then decreased constantly with an increase in temperature. The parameters reached their maximum value at 50 °C. The maximum air leakage intensity Qmax followed a trend opposite to that of the two aforementioned parameters. With an increase in temperature, Qmax first decreased and then increased. The results provide valuable information for predicting spontaneous combustion of coal, which can help prevent or mitigate risks in industrial mining.

The present study investigates the overcharge cycling effect on thermal behavior, structure, and electrode material of lithium-ion batteries (LIB) with a Lix(Ni0.3Co0.3Mn0.2)O2 cathode. The thermal behavior of LIBs with different overcharged degrees was studied using vent sizing package 2 and differential scanning calorimetry. Changes in the internal composition of the batteries during overcharge were observed using a scanning electron microscope and an inductively coupled plasma optical emission spectrometer. The results indicate that the overcharge process can be divided into four stages. A battery was more likely to trigger thermal runaway during overcharge under adiabatic conditions than in an ambient environment. During overcharge, the surface temperature of a 150% state-of-charge (SOC) battery was approximately 3.0 °C higher than that of a 100% SOC battery. Because of generated gas and lithium deposition during overcharge cycling, the battery thickness increases and coulombic efficiency decreases. The apparent exothermic onset temperature ( T 0 ) of a battery with 150 % SOC was 87 °C below that of a 100 % SOC battery. Cathode material becomes highly reactive when the battery was overcharged to 150 % SOC. Here, the released heat was 1026.4 J/g. These results provide feasible support for understanding the overcharge mechanism and battery management system.