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Abstract  

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.

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Abstract

When above certain temperature limits, lauroyl peroxide is an unstable material. If the thermal source cannot be properly governed during any stage in the preparation, manufacturing process, storage or transport, runaway reactions may inevitably be induced immediately. In this study, the influence of runaway reactions on its basic thermal characteristic was assessed by evaluating thermokinetic parameters, such as activation energy (E a) and frequency factor (A) by thermal activity monitor III (TAM III). This was achieved under five isothermal conditions of 50, 60, 70, 80, and 90 °C. Vent sizing package 2 (VSP2) was employed to determine the maximum pressure (P max), maximum temperature (T max), maximum self-heating rate ((dT dt −1)max), maximum pressure rise rate ((dP dt −1)max), and isothermal time to maximum rate ((TMR)iso) under the worst case. Results of this study will be provided to relevant plants for adopting best practices in emergency response or accident control.

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Abstract  

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.

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Abstract  

The effect of initial temperatures (100, 150, and 200 °C), operating pressures (101 and 202 kPa), and various loading oxygen concentrations (21, 17, 14…oxygen vol.%) on the flammability hazard evaluations for the mixtures of benzene and methanol (100/0, 75/25, 50/50, 25/75, and 0/100 vol.%) by using rough set method, was studied. The results indicated that the most important influence factor was the operating pressure. There is no significant difference in the safety assessment for the different concentrations of mixtures. This study proposed a helpful reference for a related practical plant combined with experimentally and theoretically feasible way for flammability prevention and protection.

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Abstract  

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.

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Acta Chromatographica
Authors: Mei-Xia Zhu, Sheng-Nan Li, Hai-Dan You, Bin Han, Zhi-Ping Wang, Yan-Xi Hu, Jin Li, and Yu-Feng Liu

High-performance liquid chromatography coupled with photodiode array detection and evaporative light scattering detection (HPLC—DAD—ELSD) was established to determine paeoniflorin and albiflorin simultaneously in Radix Paeoniae Rubra. The assay was performed on a Diamonsil C18 (4.6 mm × 250 mm, 5 μm) column by a gradient elution program with acetonitrile and aqueous formic acid (0.05% v/v) as mobile phase at a flow rate of 1.0 mL min−1. The detection wavelength of DAD was 230 nm, and the evaporator tube temperature of ELSD was set at 110 °C with the nebulizing gas flow rate of 3 L min−1. The temperature of column was kept at 30 °C. The linear ranges of paeoniflorin and albiflorin were within 0.050–1.510 mg mL−1 and 1.007–5.035 mg mL−1. The recoveries of paeoniflorin and albiflorin were 96.2–102.9% and 95.0–102.4%, respectively, while the relative standard deviation (RSD) of them was 0.2–2.5%. This method was quick, simple, accurate, and specific. It could be used for the quality control of Radix Paeoniae Rubra. The proposed approach was expected as a powerful tool for the quality control of Radix Paeoniae Rubra.

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Fire and explosion hazard evaluation for the acetone aqueous solutions

Using weighting analysis of influence factors by grey system theory and 20-L-apparatus flammability investigations

Journal of Thermal Analysis and Calorimetry
Authors: Yi-Ming Chang, Mei-Li You, Chien-Hung Lin, Siou-Yuan Wu, Jo-Ming Tseng, Chun-Ping Lin, Yaw-Long Wang, and Chi-Min Shu

Abstract

The prevention of fire and explosion is recognized as an imperative necessity that is a first priority in all operating management details of the chemical process industries. Based on significant research and original emphasis on loss control and disaster prevention, this study investigated the flammability characteristics, comprising the lower/upper explosion limit (LEL and UEL), maximum explosion overpressure (P max), maximum rate of explosion pressure rise [(dP dt −1)max], gas or vapor deflagration index (K g), and explosion class (St class) of four acetone aqueous solutions [water vapor (steam)/acetone: 75/25, 50/50, 25/75, and 0/100 vol.%], and discussed the effect of inert steam (H2O(g)) on them. Interactive influences of various loading fuel concentrations and initial testing conditions of 150, 200 °C, and 101, 202 kPa on flammability characteristics were revealed via a 20-L-apparatus. Weighting analysis of the above influence factors was explored by employing the GM(h,N) grey system theory for rating their fire and explosion hazard degrees both specifically and quantitatively. The results indicated that the most important influence factor was the initial pressure that the manager or engineer in such a steam/acetone mixing system should consider to be well-controlled first. The second influence factor in GM(1,N) and GM(0,N) model was the initial temperature and steam/acetone mixing concentration, but the third influence factor was individual contrariwise. This study established a complete flammability hazard evaluation approach that is combined with an experimentally and theoretically feasible way for fire/explosion prevention and protection. The outcomes would be useful for positive decisions for safety assessment for the relevant practical plants or processes.

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Journal of Thermal Analysis and Calorimetry
Authors: Li-Fang Song, Chun-Hong Jiang, Jian Zhang, Li-Xian Sun, Fen Xu, Wan-Sheng You, Yi Zhao, Zhi-Heng Zhang, Mei-Han Wang, Yutake Sawada, Zhong Cao, and Ju-Lan Zeng

Abstract  

A novel metal-organic frameworks [Cu2(OH)(2,2′-bpy)2(BTC) · 2H2O]n (CuMOF, BTC = benzene-1,3,5-tricarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) has been synthesized hydrothermally and characterized by single crystal XRD, FT-IR spectra. The low-temperature molar heat capacities were measured by temperature modulated differential scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference temperature 298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability and the decomposition mechanism of CuMOF were investigated by TG-MS (thermogravimetry-mass spectrometer). A four-stage mass loss was observed in the TG curve. MS curve indicated that the gas products for oxidative degradation of CuMOF were H2O, CO2, NO and NO2.

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