Search Results

You are looking at 1 - 10 of 11 items for

  • Author or Editor: Sheng-Hung Wu x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

This article studies the thermokinetics and safety parameters of cumene hydroperoxide (CHP) manufactured in the first oxidation tower. Vent sizing package 2 (VSP2), an adiabatic calorimeter, was employed to determine reaction kinetics, the exothermic onset temperature (T 0), reaction order (n), ignition runaway temperature (T C, I), etc. The n value and activation energy (E a) of 15 mass% CHP were calculated to be 0.5 and 120.2 kJ mol−1, respectively. The heat generation rate (Q g) of 15 mass% CHP compared with hS (cooling rate) = 6.7 J min−1 K−1 of heat balance, the T S,E and the critical extinction temperature (T C, E) under 110 °C of ambient temperature (T a) were calculated 111 and 207 °C, respectively. The Q g of 15 mass% CHP compared with hS = 0.3 J min−1 K−1 of heat balance was applied to determine the T C, I that was evaluated to be 116 °C. This article describes the best operating conditions when handling CHP, starting from the first oxidation tower.

Restricted access

Abstract

Tert-butyl peroxide (TBPO), is a typical organic peroxides (OPs), which is widely applied as initiator in poly-glycidyl methacrylate (PGMA) reaction, and is employed to provide a free-radical in frontal polymerization, and which has also caused many thermal runaway reactions and explosions worldwide. To find an unknown and insufficient hazard information for an energetic material, differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2) were employed to detect the fundamental thermokinetic parameters involving the exothermic onset temperature (T 0), heat of decomposition (ΔH d), temperature rise rate (dT · dt −1), time to maximum rate under adiabatic situation (TMRad), pressure rise rate (dP · dt −1), and maximum pressure (P max), etc. The T 0 was calculated to be 130 °C using DSC and VSP2. Activation energy (E a) of TBPO was evaluated to be 136 kJ mol−1 by VSP2. In view of the loss prevention, calorimetric applications and model evaluation to integrate thermal hazard development are adequate means for inherently safer design.

Restricted access

Abstract

Oxygen (O2) or air is widely applied globally to yield cumene hydroperoxide (CHP) in a cumene oxidation tower. In previous studies, CHP has been identified as a thermally hazardous chemical. This study was used to evaluate thermal hazard of CHP in cumene using differential scanning calorimetry and vent sizing package 2 (VSP2). Self-accelerating decomposition temperature (SADT), self-heating rate, exothermic onset temperature (T 0), critical temperature (T c), time to maximum rate (TMR), activation energy (E a), etc., were employed to prevent and protect thermal runaway reaction and explosion in the manufacturing process and/or storage area. The reaction order (n) of CHP was evaluated to be 0.5 in this study. The E a was determined to be 122 kJ mol−1 by VSP2. High volume of CHP with 0 rpm of stirring rate by VSP2 was more dangerous than a low one. Control of stirring rate should be a concern in process safety management program. In view of proactive loss prevention, inherently safer handling procedures and storage situations should be maintained in the chemical industries.

Restricted access

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.

Restricted access

Abstract  

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 (ΔH d) and exothermic onset temperature (T 0), 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, T 0, heat of decomposition (ΔH d), and activation energy (E a) of DCPO mixed with HNO3 were calculated to be 70 °C, 911 J g−1, and 33 kJ mol−1, respectively.

Restricted access

Abstract

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.

Restricted access

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.

Restricted access

Abstract  

Volatile organic compounds (VOCs) are the main factors involved in pollution control and global warming in industrialized nations. Various treatment methods involving incineration, adsorption, etc., were employed to reduce VOCs concentration. Various absorbents, such as activated carbon, zeolite, silica gel or alumina, and so on were broadly used to adsorb VOCs in various industrial applications. Differential scanning calorimetry (DSC) was handled to analyze the thermal characteristics of absorbents. Typically, a scanning electron microscope (SEM) has been used to evaluate the structure variation of absorbents under high temperature situations. In view of pollution control and loss prevention, versatility and analysis of recycled adsorbents are necessary and useful for various industrial applications.

Restricted access

Abstract  

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.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Sheng-Hung Wu, Chu-Chin Hsieh, Chung-Cheng Chiang, Jao-Jia Horng, Wei-Ping Pan, and Chi-Min Shu

Abstract

Volatile organic compounds (VOCs) and greenhouse gases are the main factors involved in pollution control and global warming. Various treatment methods involving incineration, adsorption, etc., have been employed to reduce VOCs and greenhouse gases concentration in the operating environment and atmosphere. Activated carbon, zeolite, silica gel, and alumina have been broadly used to adsorb pollutants in various industrial applications. Based on the promising effect of adsorption, we analyzed and identified the thermal phenomena of home-made zeolite using various instruments. The endothermic reaction under 100 °C of home-made zeolite was identified as steam adsorption, which is an important discovery. The optimal adsorption temperatures of home-made zeolite have been determined at 200–550 °C.

Restricted access