TY - JOUR A1 - Blankenhagel, Paul A1 - Wehrstedt, Klaus-Dieter A1 - Mishra, K. B. A1 - Steinbach, J. T1 - The capability of commercial CFD code to predict organic peroxide fireball characteristics JF - Journal of Hazardous Materials N2 - Fireballs of liquid organic peroxides differ from those of liquid hydrocarbon fuels. Modified equations for predicting the fireball diameter, height, surface emissive power and the duration in dependence of the fuel mass are presented for di-tert-butyl peroxide. They base on 13 steel drum tests with fuel masses from 10 kg to 168 kg. Moreover, computational fluid dynamics simulations are performed using the laminar flamelet approach and a statistically turbulence treatment. Fireballs involving peroxide from 10 kg to 80 kg were simulated and their properties compared to the experimentally developed models. The deviations of each property are partially compensating each other leading to an adequate prediction of thermal safety distances for both, a time-independent and a time-averaged treatment. Simulations prove to be a good tool for predicting thermal radiation hazards of fireball scenarios. KW - Fireball KW - CFD simulation KW - Organic peroxide KW - Fire safety KW - DTBP PY - 2019 DO - https://doi.org/10.1016/j.jhazmat.2018.11.011 SN - 0304-3894 SN - 1873-3336 VL - 365 SP - 386 EP - 394 PB - Elsevier AN - OPUS4-47054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blankenhagel, Paul A1 - Wehrstedt, Klaus-Dieter A1 - Steinbach, J. A1 - Mishra, K. B. T1 - Thermal radiation assessment of fireballs using infrared camera JF - Journal of Loss Prevention in the Process Industries N2 - The thermal radiation impact of organic peroxide fireballs is experimentally assessed using an infrared camera. Fireballs are generated while liquid peroxide filled steel drums are subjected to gas burner fire at different heating rates. Three large burning clouds are observed with varying flame characteristics. Thermal radiation properties are assessed by infrared images with the presented methods. Despite of the two-dimensional temperature fields, the flames are treated and characterized as three-dimensional objects. Fireball diameters and heights are calculated based on a representing radiating sphere with the same cloud volume. By the use of the solid flame model and assumptions for emissivity and transmissivity, heat fluxes and thermal radiation doses against distance are predicted. Thermal safety distances are presented based on the maximum irradiance and the allowed exposure time. The validation of the maximum and time-dependent radiation fields is achieved through heat flux sensors in varying distances to the fireball. The results prove the use of an infrared camera and a volume based size calculation to fully assess the thermal radiation hazards of fireballs. KW - Fireball KW - Thermal radiation KW - Infrared camera KW - Organic peroxide KW - Safety distances PY - 2018 DO - https://doi.org/10.1016/j.jlp.2018.04.008 SN - 0950-4230 VL - 54 SP - 246 EP - 253 PB - Elsevier AN - OPUS4-45277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blankenhagel, Paul A1 - Wehrstedt, Klaus-Dieter A1 - Xu, S. A1 - Mishra, K. B. A1 - Steinbach, J. T1 - A new model for organic peroxide fireballs JF - Journal of Loss Prevention in the Process Industries N2 - Organic peroxides are capable to form fireballs with explosive violence. Only fireball models for liquid hydrocarbon fuels are available for the assessment of the thermal radiation properties. Because the development of such fireballs usually differ from those of organic peroxides the properties need to be characterized by modified equations. In this study liquid organic peroxide fireballs from 16 kg to 155 kg substance masses are characterized and compared to selected existing correlations. Flame characteristics and irradiances are measured with infrared cameras and heat flux sensors. All fireballs are consequences of simulated worst case scenarios where filled steel drums are engulfed by fire with varying heat impact. The differences of the given semi-empirical equations and the presented experimental work are explained. A new model is proposed for organic peroxide fireballs by modifying the constants of the known equations. The thermal radiation impact and safety distances are calculated and compared. KW - Organic peroxide KW - Fireball KW - Thermal radiation KW - Safety distances PY - 2017 DO - https://doi.org/10.1016/j.jlp.2017.10.002 SN - 0950-4230 VL - 50 IS - Part A SP - 237 EP - 242 PB - Elsevier Science AN - OPUS4-43069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Lutz A1 - Knorr, Annett T1 - Transformation of the 2nd step of a peroxyester synthesis from semi-batch to continuous mode JF - Chemical engineering and processing N2 - Organic peroxides are known for their decomposition behaviour and for considerable heat release connected with pressure build up. Efforts are required to run the industrial synthesis in semi-batch mode on safe condition. With the aim to use advantages as good heat transfer and small hold up, the synthesis of a peroxycarboxylic ester, namely tert-Butyl peroxy-2-ethylhexanoate (TBPEH), was transformed into continuous mode using a tube reactor with inner dimension of 1 mm. An appraisal of the critical diameter of the tube was done in advance. The use of an ultrasonic device allowed for specific reaction parameters a nearly complete conversion of the educts. KW - Organic peroxide KW - Tubular reactor KW - Process safety KW - Continuous mode KW - Ultrasound PY - 2013 DO - https://doi.org/10.1016/j.cep.2013.03.019 SN - 0255-2701 VL - 70 SP - 217 EP - 221 PB - Elsevier CY - Lausanne AN - OPUS4-28937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Lutz A1 - Knorr, Annett T1 - Calorimetric study of peroxycarboxylic ester synthesis JF - Journal of hazardous materials N2 - Exothermic reactions involving organic peroxides carry a high potential hazard and must be considered with care. A safe handling requires, among others, the assessment of thermal process safety, for which safety characteristics like overall heat production and the resulting adiabatic temperature rise are essential. The article presents the results of the calorimetric investigation of the synthesis of four peroxycarboxylic esters, three tert-Butyl and one tert-Amyl peroxycarboxylic ester. In the two-step synthesis the second one clearly shows the higher exothermic potential. The overall heat production lies in the range of 126–135 kJ/mol and is nearly independent of the carboxylic acid residual in the tert-Butyl peroxycarboxylic ester. The calculated adiabatic temperature rise is 70–80 K. Influence of temperature and feed rate on the heat generation is discussed for one species. A grading of the synthesis with respect to temperature levels according to the criticality classes by Stoessel leads to the most critical for an exothermic reaction. KW - Reaction calorimetry KW - Organic peroxide KW - Peroxycarboxylic ester KW - Process safety PY - 2009 DO - https://doi.org/10.1016/jhazmat.2008.07.032 SN - 0304-3894 VL - 163 IS - 2-3 SP - 1403 EP - 1407 PB - Elsevier CY - Amsterdam AN - OPUS4-18943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -