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Sun F.,Sinopec | Xie C.-X.,State Key Laboratory of Safety and Control for Chemicals | Zhang F.,National Registration Center for Chemicals | Jin M.-P.,National Registration Center for Chemicals | Wang Z.-G.,National Registration Center for Chemicals
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2012

In order to study the influence of pH value on the thermal hazard of hydrogen peroxide, VSP2 (Vent Size Package 2) was used to analyze the thermal behavior of hydrogen peroxide (mass fraction 27.5%) with different pH values of 1.8, 4, 5, 6, 7, 8 under adiabatic condition. The adiabatic decomposition characteristics of the hydrogen peroxide with different pH values were recorded. The thermal decomposition kinetics of the decomposition reaction concerned was obtained. The time to the maximum reaction rate at 30°C under adiabatic condition was also worked out from the kinetics data. The results show that as the pH value of hydrogen peroxide increasing, the onset exothermic temperature decreases, and the time to the maximum reaction rate under adiabatic conditions gets shorter, so the risk probability of thermal runaway significantly increases. When hydrogen peroxide is stored in the industrial conditions, there is a certain risk when pH value is 6, and thermal runaway is almost inevitable when pH value is more than 7.

Sun F.,Sinopec | Xue Y.,Sinopec | Xie C.,National Registration Center for Chemicals | Jin M.,National Registration Center for Chemicals | Huang F.,National Registration Center for Chemicals
Huagong Xuebao/CIESC Journal | Year: 2012

The thermal hazard of organic peroxides should be assessed to predict and avoid runaway decomposition. In this paper, the Setaram C80 was used to investigate thermal decomposition of several organic peroxides such as cumene hydroperoxide(CHP), tert-butyl hydroperoxide(TBHP), dicumyl peroxide(DCP), di-tert-butyl peroxide(DTBP), benzoyl peroxide(BPO), tert-butyl peroxybenzoate(TBPB), methyl ethyl ketone peroxide(MEKP), 2, 5-dimethyl-2, 5-di(tert-butylperoxy)hexane(DHBP) and 1, 1-di-(tert-butylperoxy)-3, 3, 5-trimethylcyclohexane(TMCH). Decomposition heat of the organic peroxides was calculated from isothermal scanning curves. The nth-order or autocatalytic reaction kinetics model was established for these organic peroxides, and self accelerating decomposition temperature(SADT) was derived by using Semenov model. The results showed that decomposition of the organic peroxides mostly followed nth-order model with approximate reaction order of 1, however, some of them preferred to autocatalytic model. The SADT of the organic peroxides calculated was in good agreement with values from literatures, demonstrating reaction kinetics fitting and SADT calculating in this paper are of scientific. © 2012 All Rights Reserved.

Zhang H.,State Key Laboratory of Safety and Control for Chemicals | Zhang H.,Sinopec | Zhang H.,National Registration Center for Chemicals | Wang N.,State Key Laboratory of Safety and Control for Chemicals | And 8 more authors.
Huagong Xuebao/CIESC Journal | Year: 2012

The article reveals the spontaneous ignition characteristic of activated carbon(AC) as well as its key influencing factors in order to avoid or reduce the spontaneous ignition risk of AC in the process of storage and transportation. The AC samples were successfully prepared with cottonwood powder as carbon precursor and zinc chloride as activated agent at temperature from 300°C to 700°C, and the variation of spontaneous ignition temperature with the activation temperature was also investigated. The microstructure and surface functional groups of AC samples were characterized by X-ray diffraction(XRD) and Fourier transform infrared(FT-IR) spectra and the thermostability was studied by simultaneous thermal analyzer(STA). The results show that activation temperature has a great influence on the spontaneous ignition temperature of AC samples. Spontaneous ignition becomes easier if decreasing the activation temperature, which is attributed to the gradual increase of the quantities or varieties of surface functional groups of AC. It is also confirmed that the DSC and TG curves of the AC samples tend to shift to the high-temperature region with the activation temperature increasing. In other words, a higher activation temperature in the preparation process is beneficial to reduce the spontaneous ignition risk of AC. © All Rights Reserved.

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