Thermal explosion and runaway reaction simulation of lauroyl peroxide by DSC tests

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 (ΔH_d), and other safety parameters for loss prevention of runaway reactions and thermal explosions. Frequency factor (A) and activation energy (E_a) 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.     

Reactivity in the solid-state between ZnWO<Subscript>4</Subscript> and some rare-earth metal molybdates RE<Subscript>2</Subscript>MoO<Subscript>6</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Y,Sm, Eu,Gd, Dy,Ho, Er and Lu)

Organic peroxides (OPs) have caused many momentous explosions and runaway reactions, resulting from thermal instability, chemical pollutants, and even mechanical shock. In Taiwan, dicumyl peroxide (DCPO), due to its unstable reactive nature, has caused two thermal explosions and runaway reaction incidents in the manufacturing process. To evaluate thermal hazards of DCPO in a batch reactor, we studied thermokinetic parameters, such as heat of decomposition (†H _d), exothermic onset temperature (T ₀), maximum temperature rise ((dT/dt)_max), maximum pressure rise ((dP/dt)_max), self-heating rate (dT/dt), etc., via differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2).     

Runaway reaction of lauroyl peroxide with nitric acid by DSC

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.     

Runaway effects of nitric acid on methyl ethyl ketone peroxide by TAM III tests

Methyl ethyl ketone peroxide (MEKPO) is an unstable material above certain limits of temperature, decomposing into chain reactions by radicals. The influence of runaway reactions on this basic characteristic was assessed by evaluating kinetic parameters, such as activation energy (E _a ), frequency factor (A), etc., by thermal activity monitor III (TAM III). This was done under three isothermal conditions of 70, 80, and 90 °C, with MEKPO 31 mass% combined with nitric acid (HNO₃ 6 N) and sodium nitrate (NaNO₃ 6 N). Nitric acid mixed with MEKPO gave the maximum heat of reaction (△H _d ) and also induced serious reactions in the initial stage of exothermic process under the three isothermal temperatures. The time to maximum rate (TMR) also decreased when HNO₃ was mixed with MEKPO. Thus, MEKPO combined with HNO₃ 6 N forms a very hazardous mixture. Results of this study will be provided to relevant plants for alerting their staff on adopting best practices in emergency response or accident control.     

Reaction hazard analysis for the thermal decomposition of cumene hydroperoxide in the presence of sodium hydroxide

Organic peroxides have caused many serious explosions and fires that were promoted by thermal instability, chemical pollutants, and even mechanical shock. Cumene hydroperoxide (CHP) has been employed in polymerization and for producing phenol and dicumyl peroxide (DCPO). Differential scanning calorimetry (DSC) has been used to assess the thermal hazards associated with CHP contacting sodium hydroxide (NaOH). Thermokinetic parameters, such as exothermic onset temperature (T ₀), peak temperature (T _max), and enthalpy (ΔH) were obtained. Experimental data were obtained using DSC and curve fitting using thermal safety software (TSS) was employed to obtain the kinetic parameters. Isothermal microcalorimetry (thermal activity monitor, TAM) was used to investigate the thermal hazards associated with storing of CHP and CHP mixed with NaOH under isothermal conditions. TAM showed that in the temperature range from 70 to 90°C an autocatalytic reaction occurs. This was apparent in the thermal curves. Depending on the operating conditions, NaOH may be one of the chemicals or catalysts incompatible with CHP. When CHP was mixed with NaOH, the T ₀ is lower and reactions become more complex than those associated with assessment of the decomposition of the pure peroxide. The data by curve fitting indicated that the activation energy (E _a) for the induced decomposition is smaller than that for decomposition of CHP in the absence of hydroxide.     

Evaluation of adiabatic runaway reaction of methyl ethyl ketone peroxide by DSC and VSP2

Methyl ethyl ketone peroxide (MEKPO) is generally applied to manufacturing in the polymerization processes. Due to thermal instability and high exothermic behaviors of MEKPO, if any operation is undertaken recklessly or some environmental effect is produced suddenly during the processes, fires and explosions may inevitably occur. In this study, thermal analysis was evaluated for MEKPO by differential scanning calorimetry (DSC) test. Vent sizing package 2 (VSP2) was used to analyze the thermal hazard of MEKPO under various stirring rates in a batch reactor. Thermokinetic and safety parameters, including exothermic onset temperature (T ₀), maximum temperature (T _max), maximum pressure (P _max), self-heating rate (dT dt ⁻¹), pressure rise rate (dP dt ⁻¹), and so on, were discovered to identify the safe handling situation. The stirring rates of reactor were confirmed to affect runaway and thermal hazard characteristics in the batch reactor. If the stirring rate was out of control, it could soon cause a thermal hazard in the reactor.     

Effects of cumene hydroperoxide on phenol and acetone manufacturing by DSC and VSP2

Cumene hydroperoxide (CHP) being catalyzed by acid is one of the crucial processes for producing phenol and acetone globally. However, it is thermally unstable to the runaway reaction readily. In this study, various concentrations of phenol and acetone were added into CHP for determination of thermal hazards. Differential scanning calorimetry (DSC) tests were used to obtain the parameters of exothermic behaviors under dynamic screening. The parameters included exothermic onset temperature (T ₀), heat of decomposition (ΔH _d), and exothermic peak temperature (T _p). Vent sizing package 2 (VSP2) was employed to receive the maximum pressure (P _max), the maximum temperature (T _max), the self-heating rate (dT/dt), maximum pressure rise rate ((dP/dt)_max), and adiabatic time to maximum rate ((TMR)_ad) under the worst case. Finally, a procedure for predicting thermal hazard data was developed. The results revealed that phenol and acetone sharply caused a exothermic reaction of CHP. As a result, phenol and acetone are important indicators that may cause a thermal hazard in the manufacturing process.     

Modeling liquid thermal explosion reactor containing <Emphasis Type="Italic">tert</Emphasis>-butyl peroxybenzoate

This study investigated the role played by green thermal analysis technology in promoting the use of resources, preventing pollution, reducing energy consumption and protecting the environment. The chemical tert-butyl peroxybenzoate (TBPB) has been widely employed in the petrifaction industries as an initiator of polymerization formation agent. This study established the thermokinetic parameters and thermal explosion hazard for a reactor containing TBPB via differential scanning calorimetry (DSC). To simulate thermokinetic parameters, a 5-ton barrel reactor of liquid thermal explosion model was created in this study. The approach was to develop a precise and effective procedure on thermal decomposition, runaway, and thermal hazard properties, such as activation energy (E _a), control temperature (CT), critical temperature (TCR), emergency temperature (ET), heat of decomposition (∆H _d), self-accelerating decomposition temperature (SADT), time to conversion limit (TCL), total energy release (TER), time to maximum rate under isothermal condition (TMR _iso), etc. for a reactor containing TBPB. Experimental results established the features of thermal decomposition and huge size explosion hazard of TBPB that could be executed as a reduction of energy potential and storage conditions in view of loss prevention.     

Reaction hazard analysis for cumene hydroperoxide with sodium hydroxide or sulfuric acid

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 (T ₀), maximum temperature (T _max), 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 T ₀ 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.     

Kinetics of the exothermic decomposition of 1-nitro-3-(β,β,β-trinitroethyl)-4,5-dinitroiminoimidazolidine-2-one

The kinetic parameters of the exothermic decomposition of the title compound in a temperatureprogrammed mode have been studied by means of DSC. The DSC data obtained are fitted to the integral, differential, and exothermic rate equations by the linear least-squares, iterative, combined dichotomous, and least-squares methods, respectively. After establishing the most probable general expression of differential and integral mechanism functions by the logical choice method, the corresponding values of the apparent activation energy (E _a), preexponential factor (A), and reaction order (n) are obtained by the exothermic rate equation. The results show that the empirical kinetic model function in differential form and the values of E _a and A of this reaction are (1 − α)^−4.08, 149.95 kJ mol⁻¹, and 10^14.06 s⁻¹, respectively. With the help of the heating rate and kinetic parameters obtained, the kinetic equation of the exothermic decomposition of the title compound is proposed. The critical temperature of thermal explosion of the compound is 155.71°C. The above-mentioned kinetic parameters are quite useful for analyzing and evaluating the stability and thermal explosion rule of the title compound. The text was submitted by the authors in English.     

Kinetics and thermodynamics of thermal decomposition of synthetic AlPO<Subscript>4</Subscript>·2H<Subscript>2</Subscript>O

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 (T ₀ ), maximum temperature (T _max ), 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 (E _a ) 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 T ₀ is induced earlier and the reactions become more complex than for pure CHP, and the E _a is lower than for pure CHP.     

Thermal hazard evaluation of tert-butyl hydroperoxide mixed with four acids using calorimetric approaches

Possessing thermal instability inherently, organic peroxides have caused many severe accidents in chemical industries all over the world. tert-Butyl hydroperoxide (TBHP) is usually used as initiator or oxidant because of its strong oxidizing ability in the chemical process. In this study, the thermal hazard analysis of TBHP mixed with various acids was investigated. Differential scanning calorimetry (DSC) and vent sizing package 2 were used to figure out the thermal runaway behaviors of TBHP. Thermokinetic parameters, such as exothermic onset temperature (T ₀), maximum temperature (T _max), and enthalpy (ΔH), were obtained from thermal curves. In addition, the activation energy (E _a) and rate constant (k) were calculated by the Arrhenius equation. Therefore, the T ₀ was determined to be 91.6 °C for exothermic reaction using DSC under 4 °C min^?1 of heating rate. The E _a for exothermic reaction was calculated to be 92.38 kJ mol^?1 by DSC in this study. As far as loss prevention is concerned, thermokinetic parameters are crucial to the relevant processes in the chemical industries, particularly under process upsets.     

Thermal hazard analyses and incompatible reaction evaluation of hydrogen peroxide by DSC

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.     

Thermal behavior and thermal safety on 3,3-dinitroazetidinium salt of perchloric acid

3,3-Dinitroazetidinium (DNAZ) salt of perchloric acid (DNAZ·HClO₄) was prepared, it was characterized by the elemental analysis, IR, NMR, and a X-ray diffractometer. The thermal behavior and decomposition reaction kinetics of DNAZ·HClO₄ were investigated under a non-isothermal condition by DSC and TG/DTG techniques. The results show that the thermal decomposition process of DNAZ·HClO₄ has two mass loss stages. The kinetic model function in differential form, the value of apparent activation energy (E _a) and pre-exponential factor (A) of the exothermic decomposition reaction of DNAZ·HClO₄ are f(α) = (1 − α)⁻¹/2, 156.47 kJ mol⁻¹, and 10^15.12 s⁻¹, respectively. The critical temperature of thermal explosion is 188.5 °C. The values of ΔS ^≠, ΔH ^≠, and ΔG ^≠of this reaction are 42.26 J mol⁻¹ K⁻¹, 154.44 kJ mol⁻¹, and 135.42 kJ mol⁻¹, respectively. The specific heat capacity of DNAZ·HClO₄ was determined with a continuous C _p mode of microcalorimeter. Using the relationship between C _p and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was evaluated as 14.2 s.     

Thermal runaway hazards of <Emphasis Type="Italic">tert</Emphasis>-butyl hydroperoxide by calorimetric studies

Thermal runaway reactions associated with exothermic behaviors of tert-butyl hydroperoxide (TBHP) solutions and TBHP reacting with alkaline contaminants were studied. A differential scanning calorimetry (DSC) was used to characterize these inherent behaviors of TBHP solutions with KOH, NaOH, LiOH and NH₄OH. The exothermic peak in thermal curves of TBHP solutions with different alkali were detected by DSC thermal analysis. By thermal analysis, we compared various heats of decomposition of TBHP solutions with alkaline impurities, and determined the incompatible hazards of various TBHP solutions with alkaline contaminants. Comparing with TBHP in various diluents, the adiabatic runaway reaction via vent sizing package 2 (VSP2) indicated that aqueous TBHP intrinsically possesses the phenomena of thermal explosion with dramatic self-reactive rate and pressure rise under adiabatic conditions. Many commercial organic peroxides may have different hazard behaviors. Therefore, using thermal method to classify the hazards is an important subject.     

Thermal runaway reaction evaluation of two by-products mixed with cumene hydroperoxide in the oxidation tower

Oxygen (O₂) or air is widely used to produce cumene hydroperoxide (CHP) in the cumene oxidation tower. The aim of this study was applied to analyze thermal hazard of two by-products including alpha-methylstyrene (AMS) and acetophenone (AP) in a CHP oxidation tower. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were operated to evaluate thermal runaway reaction of CHP mixed with AMS and AP. Exothermic onset temperature (T ₀), maximum temperature (T _max), activation energy (E _a), etc., that were employed to prevent and protect thermal runaway reaction and explosion in the manufacturing process and storage area. In view of proactive loss prevention, the inherently safer handling procedure and storage situation should be maintained in the chemical industries. The T ₀ of 30 mass% CHP was determined to be 105 °C by DSC. Therefore, the T ₀ of 30 mass% CHP mixed with AMS was determined to be 60–70 °C by DSC. The exothermic reaction of CHP/AP and CHP/AMS by DSC under N₂ reaction gas is thermal decomposition of oxygen–oxygen bond (–O–O–) because of the anaerobic reaction.     

Simulation approach to decomposition kinetics and thermal hazards of hexamethylenetetramine

The thermal stability of HMT under dynamic, isothermal and adiabatic conditions was investigated using differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. It is found from the dynamic DSC results that the exothermic decomposition reaction appears immediately after endothermic peak, a coupling phenomenon of heat absorption and generation, and the endothermic peak and exothermic peak were indentified at about 277–289 and 279–296 °C (T_peak) with the heating rates 1, 2, 4 and 8 °C min⁻¹. The ARC results reveal that the initial decomposition temperature of HMT is about 236.55 °C, and the total gas production in decomposition process is 6.9 mol kg⁻¹. Based on the isothermal DSC and ARC data, some kinetic parameters have been determined using thermal safety software. The simulation results show that the exothermic decomposition process of HMT can be expressed by an autocatalytic reaction mechanism. There is also a good agreement between the kinetic model and kinetic parameters simulated based on the isothermal DSC and ARC data. Thermal hazards of HMT can be evaluated by carrying out thermal explosion simulations, which were based on kinetic models (Isothermal DSC and ARC) to predict several thermal hazard indicators, such as T_D24, T_D8, TCL, SADT, ET and CT so that we can optimize the conditions of transportation and storage for chemical, also minimizing industrial disasters.

     

Prediction of incompatible reaction of dibenzoyl peroxide by isothermal calorimetry analysis and green thermal analysis technology

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 (ΔH _d), activation energy (E _a), and pre-exponential factor (k ₀), 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.     

Incompatible reaction evaluation and accident investigation of various acids in chemical industries

This article covers the incompatible properties of nitric acid (HNO₃) with formic acid (CH₂O₂), and more generally with various acids such as sulfuric acid (H₂SO₄), hydrochloric acid (HCl), and acetic acid (C₂H₄O₂). Differential scanning calorimetry (DSC) was employed to determine the thermal hazard such as heat of decomposition (ΔH _d), exothermic onset temperature (T ₀), etc., in various acids. T ₀ of HNO₃ and CH₂O₂ were determined as 50 °C using DSC. Thus it has been observed that HNO₃ mixed with CH₂O₂ should be prohibited during transportation, storage, and use. And more generally, process safety engineers and operator must take care to handle tanker and storage tank of typical acids in the transportation, storage, and manufacturing process. It is clear that there exists a need to follow and enforce in the chemical industries safety data sheets, globally harmonized system of classification and labeling of chemicals of United Nations (UN), education of safety and health, emergency response system, and process safety management. It is the aim of the present study concerning HNO₃ with various acids.     

Explosion evaluation and safety storage analyses of cumene hydroperoxide using various calorimeters

Plenty of thermal explosions and runaway reactions of cumene hydroperoxide (CHP) were described from 1981 to 2010 in Taiwan. Therefore, a thermal explosion accident of CHP in oxidation tower in 2010 in Taiwan was investigated because of piping breakage. In general, high concentration of CHP for thermal analysis using the calorimeter is dangerous. Therefore, a simulation method and a kinetic parameter were used to simulate thermal hazard of high concentrations of CHP only by the researcher. This study was applied to evaluate thermal hazard and to analyze storage parameters of 80 and 88 mass% CHP using three calorimeters for the oxidation tower, transportation, and 50-gallon drum. Differential scanning calorimetry (DSC) (a non-isothermal calorimeter), thermal activity monitor III (TAM III) (an isothermal calorimeter), and vent sizing package 2 (VSP2) (an adiabatic calorimeter) were employed to detect the exothermic behavior and runaway reaction model of 80 and 88 mass% CHP. Exothermic onset temperature (T ₀), heat of decomposition (ΔH _d), maximum temperature (T _max), time to maximum rate under isothermal condition (TMR_iso) (as an emergency response time), maximum pressure (P _max), maximum of self-heating rate ((dT/dt)_max), maximum of pressure rise rate ((dP/dt)_max), half-life time (t _1/2), reaction order (n), activation energy (E _a), frequency factor (A), etc., of 80 and 88 mass% CHP were applied to prevent thermal explosion and runaway reaction accident and to calculate the critical temperature (T _c). Experimental results displayed that the n of 80 and 88 mass% CHP was determined to be 0.5 and the E _a of 80 and 88 mass% CHP were evaluated to be 132 and 134 kJ mol^?1, respectively.