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To simulate a full fire engulfment during transportation or storage a closed removable head steel drum filled with 200 l Di-tert-butyl peroxide (DTBP) is subjected to a wood fire. Due to the enormous heat flux and the exothermic self-decomposition large flames arise and finally multiple fireballs occur. The fireballs consume up to 20 % of the total mass (20 % equals to 31 kg). They are characterized by high surface emissive power and large flames associated with high thermal radiation causing spontaneous ignition of objects in the surrounding. The measured sizes of the DTBP fireballs are smaller compared to the results of the general equations for hydrocarbon fireballs. Because these equations are recommended by the Health and Safety Executive (UK) to be applicable for organic peroxides explicit comparisons of DTBP with LPG, diesel and gasoline concerning the characteristics of fireballs are carried out. Also the burning time is compared and confirms a faster combustion of the peroxide. Moreover, the development of size and emissive power for DTBP and diesel fireballs are compared in a normalized graph. The results provide the assumption that new empirical models are required to be developed for hazard assessment of organic peroxide fireballs.
To simulate a full fire engulfment during transportation or storage a closed removable head steel drum filled with 200 l Di-tert-butyl peroxide (DTBP) is subjected to a wood fire. Due to the enormous heat flux and the exothermic self-decomposition large flames arise and finally multiple fireballs occur. The fireballs consume up to 20 % of the total mass (20 % equals to 31 kg). They are characterized by high surface emissive power and large flames associated with high thermal radiation causing spontaneous ignition of objects in the surrounding. The measured sizes of the DTBP fireballs are smaller compared to the results of the general equations for hydrocarbon fireballs. Because these equations are recommended by the Health and Safety Executive (UK) to be applicable for organic peroxides explicit comparisons of DTBP with LPG, diesel and gasoline concerning the characteristics of fireballs are carried out. Also the burning time is compared and confirms a faster combustion of the peroxide. Moreover, the development of size and emissive power for DTBP and diesel fireballs are compared in a normalized graph. The results provide the assumption that new empirical models are required to be developed for hazard assessment of organic peroxide fireballs.
Summary of recent research activities at BAM concerning large scale fireballs of organic peroxides (OP). For the tests performed in Nanjing, China, the experimental setup and data aquisition is briefly shown and results are discussed compared with semi-empirical models. A new model is proposed for assessing OP fireballs. Thermal safety distances are calculated and compared for the three large tests.
Summary of recent research activities at BAM concerning fireballs of organic peroxides. Experimental setup and data aquisition is briefly shown and results are discussed compared with semi-empirical models. Moreover, approaches for CFD simulation methods are presented. Finally, collaborative research of BAM and NUST (China) is shown as an example for future work.
Final report of research activities at BAM concerning large scale fireballs of organic peroxides (OP). New models for OP fireball diameter, duration, height and Surface Emmissive Power (SEP) are proposed and discussed based on a large number of large-scale and small-scale experiments using Di-tert-butylperoxide (DTBP) as a liquid OP and heptane as a liquid hydrocarbon fuel. Finally, CFD simulations are used to predict the fireball parameters: diameter, duration, height and SEP. Also the impact on the German storage regulations for organic peroxides are discussed.
Summary of recent research activities at BAM concerning large scale fireballs of organic peroxides (OP). Videos of the tests performed in Nanjing, China, are presented. A new model for OP fireball diameter, duration, height and SEP is proposed based on all experiments. In addition, small scale test results using DTBP and heptane are presented. Finally, CFD simulation is used to predict the fireball parameters: diameter, duration and height.
Organic peroxides (OP) are thermally unstable and burn rapidly due to exothermic self-decomposition capabilities. Since fireballs can be formed under certain worst case conditions the understanding of burning phenomena and radiation characteristics need to be improved to prevent damage of humans and infrastructure. An appropriate method for real-scale Evaluation can be the use of CFD simulations with the objective of reducing time-consuming and costly outdoor experiments.
Single and multiple fireballs of di-tert-butyl peroxide are numerically investigated using ANSYS CFX. Calculations contain varying inlet conditions, scale-adaptive shear stress turbulence modeling and one-step combustion reaction on a three-dimensional hexahedral mesh. Time-resolved flame temperatures, sizes and thermal radiation are compared to experimental results. There, fireballs were generated by fire engulfment of steel drums containing 200 l substance. After a vigorous burning, the remaining peroxide forms single and multiple fireballs involving 10 % to 20 % of the initial amount. The comparison of all simulations and two selected experiments show the special numerical treatment required for organic peroxides. Finally, the numerical predictions of irradiance in 30 m distance to the fire show a good agreement for both experiments. This proves the use of CFD as an appropriate method for thermal hazard assessment and the prediction of safety distances for organic peroxide fireballs.
The burning behaviour and thermal radiation of pool fires of organic peroxides (OP) have
been studied by several authors in the past. It was shown that mass burning rates, flame
temperatures and thus the Surface Emissive Power (SEP) of OP exceed to that of hydrocarbons
considerably. These facts lead to further investigations of even dangerous worst
case scenarios i.e. related to storage and transportation. A metal drum containing 200 l of
DTBP (Di-tert-butyl peroxide) is investigated under a surrounding wood fire. Due to a
higher heat flux to the substance, the mass burning rate reaches multiples of an equivalent
pool fire and results in several fireballs. The analyses of thermographic camera images
and radiometer measurements show higher flame lengths, higher temperatures and therefore
increased thermal radiation compared to OP pool fires. The resulting greater safety
distances for a DTBP fireball event are discussed.