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Abstract  

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).

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Abstract  

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.

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Abstract  

The highly reactive and unstable exothermal features of methyl ethyl ketone peroxide (MEKPO) have led to a large number of thermal explosions and runaway reaction accidents in the manufacturing process. To evaluate the self-accelerating decomposition temperature (SADT) of MEKPO in various storage vessels, we used differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2). The thermokinetic parameters were, in turn, used to calculate the SADT from theoretical equations based on the Semenov model. This study aimed at the SADT prediction value of various storage vessels in Taiwan compared with the UN 25 kg package and UN 0.51 L Dewar vessel. An important index, such as SADT, temperature of no return (T NR) and adiabatic time maximum rate (TMRad), was necessary and useful to ensure safe storage or transportation for self-reactive substances in the process industries.

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Abstract  

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 (ΔH d) and exothermic onset temperature (T 0).

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Abstract  

Methyl ethyl ketone peroxide (MEKPO) possesses complex structures which have caused many incidents involving fires or explosions by mixing with incompatible substances, external fires, and others. In this study, reactivities or incompatibilities of MEKPO with inorganic acids (HCl, HNO3, H3PO4 and H2SO4) were assessed by differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2). Parameters obtained by the above-mentioned devices could be readily employed to discuss the runaway reaction, such as onset temperature (T 0), heat of reaction (ΔH d), time to maximum rate (TMR), maximum self heat rate (dT/dt)max, adiabatic temperature rise (ΔT ad), maximum pressure of decomposition (P max) and so on. Mixing MEKPO with hydrochloric acid resulted in the lowest T 0 among inorganic acids. Nitric acid not only lowered the T 0 but also delivered the highest heat releasing rate or self heat rate (dT/dt), which was concluded to be the worst case in terms of contamination hazards during storage or transportation of MEKPO.

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Abstract  

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 (T 0), heat of decomposition (ΔH d), 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 T 0, 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.

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temperature ( T 0 ), heat of decomposition (Δ H d ), maximum temperature ( T max ), maximum pressure ( P max ), self-heating rate (d T d t −1 ), pressure rise rate (d P d t −1 ), etc., by using differential scanning calorimetry (DSC) and vent sizing package

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its thermokinetic parameters measured by vent sizing package 2 (VSP2). The results could be applied to simulate runaway reaction and thermal explosion of vessels containing 20 mass% MEKPO subjected to external fire scenarios. The simulation technique

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the endothermic melting belongs to the quasi-AC type [ 4 ]. In this study, vent sizing package 2 (VSP2) and thermal activity monitor III (TAM III) were used to analyze the thermokinetic parameters and safety indices. VSP2 is an adiabatic

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and b fire and explosion by CHP Vent sizing package 2 (VSP2) is an adiabatic calorimeter that can be used to determine thermokinetics and safety parameters. This study was used to investigate thermal hazard and

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