TY - JOUR A1 - Krietsch, Arne A1 - Reyes Rodriguez, M. A1 - Kristen, A. A1 - Kadoke, D. A1 - Abbas, Z. A1 - Krause, U. T1 - Ignition temperatures and flame velocities of metallic nanomaterials JF - Jounal of Loss Prevention in the Process Industries N2 - The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powd ers (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples. KW - Dust explosions KW - Nanomaterial KW - Flame propagation KW - Minimum ignition temperature PY - 2021 DO - https://doi.org/10.1016/j.jlp.2021.104482 SN - 0950-4230 VL - 2021 IS - 71 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-54076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tschirschwitz, Rico A1 - Schröder, Volkmar A1 - Brandes, E. A1 - Krause, U. T1 - Determination of explosion limits - Criterion for ignition under non-atmospheric conditions JF - Journal of Loss Prevention in the Process Industries N2 - Many industrial processes are run at non-atmospheric conditions (elevated temperatures and pressures, other oxidizers than air). To judge whether and if yes to what extent explosive gas(vapor)/air mixtures will occur or may be generated during malfunction it is necessary to know the safety characteristic data at the respective conditions. Safety characteristic data like Explosion limits, are depending on pressure, temperature and the oxidizer. Most of the determination methods are standardized for ambient conditions. In order to obtain determination methods for non-atmospheric conditions, particularly for higher initial pressures, reliable ignition criteria were investigated. Ignition tests at the explosion Limits were carried out for mixtures of methane, propane, n-butane, n-hexane, hydrogen, ammonia and acetone in air at initial pressures up to 20 bar. The tests have been evaluated according to different ignition criteria: visual flame propagation, temperature and pressure rising. It could be shown that flame propagation and occasionally self-sustained combustion for several seconds occurred together with remarkable temperature rise, although the pressure rise was below 3%. The results showed that the combination of a pressure rise criterion of 2% and a temperature rise criterion of 100 K seems to be a suitable ignition criterion for the determination of explosion limits and limiting oxidizer concentration at higher initial pressures and elevated temperatures. The tests were carried out within the framework of a R&D project founded by the German Ministry of Economics and Technology. KW - Explosion limits KW - Ignition criterion KW - Standardization KW - Non-atmospheric conditions PY - 2015 DO - https://doi.org/10.1016/j.jlp.2015.01.012 SN - 0950-4230 VL - 36 SP - 562 EP - 568 PB - Elsevier CY - Amsterdam AN - OPUS4-36954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -