Search

In addition to polypropylene, acrylonitrile, and carbonyl alcohol, propylene oxide is the fourth major derivative among propylene derivatives and one of the important basic organic chemicals. A thermal stability test of catalyst, methanol, and hydrogen peroxide (H2O2) was conducted via differential scanning calorimetry (DSC). Propylene epoxidation with H2O2 over catalyst, methanol, and propylene evenly mixed by specific pressure was carried out, and then the runaway reaction under adiabatic conditions was further simulated by the vent sizing package 2 (VSP2) to measure temperature and pressure data with respect to time of the runaway excursion. Finally, the apparent activation energy of H2O2 and propylene oxide reaction was obtained via temperature variation equation to evaluate the degree of potential hazard in industry.

Simulation tests were employed in the treatment of wastewater from seawater that was received from a specific power plant via flue gas desulfurization (FGD) for wastewater purification in this study. After water quality and compound variation were confirmed, a simulation was conducted to investigate the efficacy of pre-processing on the elimination of the majority of pollutants, like suspended solids, calcium ions, and magnesium ions. A mini scale electrodialysis reversal (EDR) mold plant was used to eliminate target pollutants, including sulfate and chloride ions. The Taguchi method was used to determine the optimal operating conditions that applied to various operating parameters, including temperature, flow rate, voltage, and current durations of power supply, to obtain the optimal operating parameters through analysis of variance (Minitab 14.0) simulation. After the simulations, the optimal parameters in the EDR process were used to demonstrate the removal efficiency of chloride, sulfate, and conductivity following treatment by EDR. The optimal operating parameters of the Taguchi method were 1 V (voltage), 3 L min−1 (flow rate), 15°C (temperature), 30 min (duration of power on), and 2 min (duration of power off). Combining the Taguchi method with the EDR process on wastewater treatment not only decreased initial conductivity from 4860 to 450 µS cm−1, but also alleviated concentrations of sulfate and chloride ions.

This article reflects on process safety fundamentals of fires and explosions for the benefit of new professionals entering the field. It provides a brief review of fire fundamentals such as the fire triangle and the respect that must be paid to the unknown ignition source. Various control methods are reviewed at the elementary level, including the reminder that the ignition source is always free. After a review of fire fundamentals, an emergency response training exercise is presented for a burning propane fire witnessed at a training facility in Taiwan. The National Fire Agency of Taiwan has built the third largest emergency response-training center in the world. The 270 acres facility is located in central Taiwan near Taichung, Taiwan. The site has 49 separate emergency response training scenarios. Scenario pads include training for fire attack on mock-ups of chemical storage facilities, tanker trucks, power transformers, passenger airliners, and shipping vessels. Overall, this article serves as a reminder of the safe guards used in fire safety and the importance of training beforehand in the event of an emergency. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 2–7, 2013

Gallium arsenide (GaAs) has both high saturated electron velocity and high electron mobility, making it useful as a semiconductor material in a variety of applications, including light-emitting diodes (LEDs), integrated circuits (ICs), and microwave appliances. A side effect of the use of gallium (Ga) is the production of a relatively large amount of hazardous waste. This study aimed at the recovery of Ga and arsenic (As) from GaAs waste using hydrometallurgical methods involving leaching and coagulation and a dry annealing process that involves annealing, vacuum separation, and sublimation by heating. Our research has shown that GaAs can be leached using nitric acid (HNO3) to obtain 100% Ga and As with a leaching solution at pH 0.1, with subsequent adjustment of the leaching solution to pH 3 with sodium hydroxide (NaOH). Another method used a leaching solution at pH 2, then adjusting to pH 11 using NaOH. Ferric hydroxide (FeO(OH)) was added at 90°C after NaOH was added to the leaching solution. At pH 2 and 11, 55.5 and 21.9% of the As could be removed from the hazardous waste, respectively. The Ga could also be precipitated. When GaAs powder was heated to 1000°C over 3 h, 100% As removal was achieved, and 92.6% of the Ga was removed by formation of 99.9% gallium trioxide (Ga2O3). Arsenic was vaporized when the temperature was elevated to 1000°C, allowing arsenic trioxide (As2O3) to condense with 99.2% purity. The Ga2O3 powder produced was then dissolved and electrolyzed, allowing for 95.9% recovery of Ga with a purity of 99.9%.

The location of the hydroelectric power plant poses a high risk to occupants seeking to escape in a fire accident. Calculating the heat release rate of transformer oil as 11.5 MW/m(2') , the fire at the Taiwan Dajia-River hydroelectric power plant was reconstructed using the fire dynamics simulator (FDS). The variations at the escape route of the fire hazard factors temperature, radiant heat, carbon monoxide, and oxygen were collected during the simulation to verify the causes of the serious casualties resulting from the fire. The simulated safe escape time when taking temperature changes into account is about 236 sec, 155 sec for radiant heat changes, 260 sec for carbon monoxide changes, and 235-248 sec for oxygen changes. These escape times are far less than the actual escape time of 302 sec. The simulation thus demonstrated the urgent need to improve escape options for people escaping a hydroelectric power plant fire. Language: en

In the chemical industries the three most common accidents are due to toxic releases, fires, and explosions, with most occurring in the form of fires and explosions. The reasons for these accidents predominantly arise out of a lack of awareness of flammability properties of flammable substances. To evaluate the fire/explosion hazards involved and ensure the safety and optimal operation of reactors, vessels or storage tanks, it is necessary to recognize the flammability characteristics of flammable materials. By means of a 20-L-Apparatus, we investigated the flammability and explosion characteristics of methane with three different inert gases (CO2, N2, and Ar) at 1 atm. 30 and 100°C, and many air concentrations. Our test results determined that the inert influence on methane by CO2 is better than N2 and Ar. The results of this article include graphs that show the lower and upper flammability regions and the explosion characteristics for these inerted systems. The flammability ranges include results for 30 and 100°C. © 2010 American Institute of Chemical Engineers Process Saf Prog, 2010

This article covers the thermal properties of cumene hydroperoxide (CHP) and dicumyl hydroperoxide (DCPO). Differential scanning calorimetry (DSC) was employed to determine the reaction kinetics, heat of decomposition (ΔHd), exothermic onset temperature (T0), reaction order (n), etc. A thermal activity monitor (TAM) was also used to detect the storage index and thermal hazard parameters under various external temperatures. The onset temperatures of CHP and DCPO were determined to be 110°C using DSC. This article describes the best operating conditions when handling CHP and DCPO. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2010

Self-reactive decompositions associated with the exothermic behavior of tert-butyl hydroperoxide (TBHP) solutions with three diluents of H2O, tert-butanol, and nonane were investigated. We used two calorimeters, Differential Scanning Calorimeter and Vent Sizing Package 2, to characterize the inherent thermal hazards of TBHP solutions. By thermal analysis, various heats of decomposition of TBHP in water, in nonane, and in tert-butanol solutions were determined to be 1622.4, 1438.8, and 753.2 J/g of TBHP, respectively. Adiabatic runaway data, such as exothermic onset temperature, maximum self-heat rate, maximum pressure rate, adiabatic time to maximum rate, and noncondensable pressure, were obtained using a VSP2. © 2007 American Institute of Chemical Engineers Process Saf Prog 2007

A microcalorimeter was used to detect and record the exothermic activity of cumene hydroperoxide under isothermal conditions in the temperature range from 75 to 90°C. Under such conditions, conventional calorimeters, such as the DSC, or adiabatic calorimeters, such as VSP2, do not detect the heat release of cumene hydroperoxide. Exothermic thermograms were recorded with microcalorimeter in isothermal tests which typically required about 20 days. The heat of reaction, onset temperature, and autocatalytic behavior were determined and compared to the results of previous studies.