TY - JOUR A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Lange, T. A1 - Klemm, E. T1 - Catalyst as ignition source of an explosion inside a microreactor N2 - The present issue reports on a specific aspect of safety engineering of the heterogeneously catalysed oxidation of ethene in a continuous-flow microreactor. Conversion of ethene and the corresponding surface temperature of the catalyst were monitored for different reactor temperatures and total flow rates with a stoichiometric ethene/oxygen mixture for total oxidation. Safe operation of the highly exothermic oxidation was possible, but not in the whole parameter range. At high reactor temperatures and flow rates, ignition of an explosion inside the microreactor caused by a hot spot on the surface of the catalyst was observed for the first time. KW - Catalyst KW - Ethene KW - Explosions KW - Hot spot KW - Microstructure KW - Safety PY - 2012 DO - https://doi.org/10.1016/j.ces.2012.08.049 SN - 0009-2509 VL - 84 SP - 540 EP - 543 PB - Elsevier CY - Amsterdam AN - OPUS4-26782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klemm, E. A1 - Liebner, Christian A1 - Heinrich, Sebastian A1 - Hieronymus, Hartmut A1 - Lange, Th. T1 - Partial Oxidation of o-Xylene to Phthalic Anhydride inside of the explosion regime using a micro structured reactor T2 - 2012 AlChE Annual Meeting CY - Pittsburgh, PA, USA DA - 2012-10-28 PY - 2012 AN - OPUS4-27035 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the heterogeneously catalyzed partial oxidation of o-xylene in the explosion regime using a microfixed bed reactor N2 - The heterogeneously catalyzed selective gas phase oxidation of o-xylene was investigated, using a microstructured fixed bed reactor, inside of the explosion regime. The reaction was carried out with high amounts of o-xylene in air and stoichiometric with oxygen using a V2O5/TiO2-catalyst prepared through grafting. There were no significant losses in the selectivity to phthalic anhydride observable, during the measurements in the explosion regime, with feed compositions of up to 7 vol% o-xylene. Also the space-time yield was up to 2.3 times higher in comparison to conventional reaction conditions. An increase of the selectivity to total oxidation products was observed at higher o-xylene concentrations between 10 and 25 vol% o-xylene, which possibly was caused by the formation of a hotspot. The investigation of the used catalyst revealed a thermally induced deactivation due to phase transition of anatase into rutil and formation of crystalline vanadium oxide. Despite that expected hotspot at high oxylene concentrations, there was no ignition or explosion of the gas mixture observable. KW - O-xylene oxidation KW - Phthalic anhydride KW - V2O5/TiO2-catalyst KW - Microfixed bed reactor KW - Explosion regime KW - Hotspot PY - 2012 DO - https://doi.org/10.1016/j.ces.2011.10.072 SN - 0009-2509 VL - 69 IS - 1 SP - 440 EP - 448 PB - Elsevier CY - Amsterdam AN - OPUS4-25463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Lange, T. A1 - Klemm, E. ED - Beyer, M. ED - Stolz, T. T1 - Zündung, Ausbreitung und Unterdrückung von Explosionen in einem Mikroreaktor N2 - Der vorliegende Beitrag behandelt spezifische Aspekte der Sicherheitstechnik bei heterogen katalysierten Oxidationsreaktionen. Ergebnisse von Explosionsuntersuchungen an Ethen-Sauerstoffgemischen in einem kontinuierlich betriebenen Mikroreaktor, die beispielsweise für den Ethylenoxidprozess relevant sind, werden vorgestellt. Der Anfangsdruck der untersuchten Eduktgemische lag zwischen 1000 hPa und 10000 hPa bei Anfangstemperaturen zwischen Umgebungstemperatur und einer Temperatur bis zu 673 K. Mikrostrukturierte Reaktoren bieten einen erweiterten Bereich von Betriebsbedingungen. Die Untersuchungen zielen auf den sicheren Betrieb eines Mikroreaktors bei Bedingungen, die bei konventionellen Reaktoren als innerhalb des Explosionsbereichs eingestuft werden, ab. In bestimmten Grenzen kann eine Unterdrückung von Explosionen in einem Mikroreaktor erreicht werden. Es ist jedoch nicht möglich, einen Mikroreaktor unter allen Bedingungen sicher zu betreiben. Aus diesen Gründen wurde die Explosionsausbreitung durch einen mikrostrukturierten Reaktor hindurch und die Zündung einer Gasphasenexplosion durch Hot-Spots in dem Reaktor untersucht. Die angewandten Untersuchungsmethoden sind Gegenstand aktueller Normungsaktivitäten. T2 - 13. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Braunschweig, Germany DA - 18.06.2013 KW - Micro Reactor KW - Explosion KW - Safety PY - 2013 SN - 978-3-95606-062-5 DO - https://doi.org/10.7795/210.20130910K SN - 1868-5838 SP - 90 EP - 98 AN - OPUS4-29849 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the partial oxidation of o-xylene in the explosion regime - microfixed bed versus catalyst coating N2 - The selective gas phase oxidation of o-xylene was investigated inside of the explosion regime using a microstructured reactor. The V2O5/TiO2 catalyst was used as microfixed bed and as catalyst coating. There were no significant losses of the selectivity to phthalic anhydride with feed compositions up to 7 vol % o-xylene observable. Above 7 vol % the selectivity decreased due to total oxidation, especially for the microfixed bed, which was probably caused by a hotspot. KW - Catalysis KW - Microreactors KW - Partial oxidation KW - Xylene KW - o-Xylene KW - Explosion regime PY - 2013 DO - https://doi.org/10.1002/cite.201200197 SN - 0009-286X SN - 1522-2640 VL - 85 IS - 4 SP - 461 EP - 466 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-30298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, T. A1 - Neher, F. A1 - Klemm, E. A1 - Heinrich, Sebastian A1 - Balcazar Pust, Emilio A1 - Liebner, Christian A1 - Hieronymus, Hartmut T1 - Heterogeneous catalysis meets micro reactors: Partial oxidations in the explosion regime N2 - Investigations on primary, secondary and tertiary explosion protection have been performed for micro reactors with slit-like channels which are coated with catalyst. Ethene/oxygen mixtures have been used as model gas mixtures representing explosion group IIB (DIN EN ISO 16852). It could be shown that the explosion regime can be significantly reduced when using micro reactors (primary explosion protection). Furthermore, safe Operation inside the explosion regime is possible with micro reactors (secondary explosion protection), but, at certain conditions thermal runaway and ignition of detonations are possible. An unexpected behaviour has been found, because thermal runaway occurred when Volumetrie flow rate was increased. This behaviour is completely opposite to that of multi tube fixed bed reactors which show an increase of safety when increasing volumetric flow rate. Micro reactors can be constructed pressure-resistant even when detonations occur inside (tertiary explosion protection). For the example of o-xylene oxidation it could be shown that space time yield can be increased significantly when entering explosion regime. T2 - DGMK International conference - Selective oxidation and functionalization: Classical and alternative routes and sources CY - Berlin, Germany DA - 13.10.2014 PY - 2014 SN - 978-3-941721-44-9 VL - 2014-3 SP - 97 EP - 105 AN - OPUS4-31759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klemm, E. A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Fischer, J. T1 - Sind Mikrostrukturreaktoren inhärent sicher? T2 - Jahrestreffen Reaktionstechnik 2009 CY - Würzburg, Germany DA - 2009-06-08 PY - 2009 AN - OPUS4-19584 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liebner, Christian A1 - Fischer, J. A1 - Hieronymus, Hartmut A1 - Klemm, E. ED - Suter, G. ED - de Rademaeker, E. T1 - Are micro reactors inherently safe? - An investigation of gas phase explosion propagation limits T2 - 13th International symposium on loss prevention and safety promotion in the process industries CY - Brugge, Belgium DA - 2010-06-06 KW - Deflagration KW - Detonation KW - Mikroreaktionstechnik KW - Mikroreaktoren KW - Sicherheitstechnik PY - 2010 SN - 978-90-76019-291 VL - 02 SP - 281 EP - 285 CY - Brugge, Belgium AN - OPUS4-21496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Fischer, J. A1 - Klemm, E. T1 - Untersuchungen zur Explosionsausbreitung in mikrostrukturierten Reaktoren T2 - 12. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik CY - Berlin, Deutschland DA - 2010-06-15 KW - Deflagration KW - Detonation KW - Mikroreaktionstechnik KW - Mikroreaktor KW - Sicherheitstechnik PY - 2010 SN - 978-3-9813550-1-7 SN - 0938-5533 SP - 7 EP - 10 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-21495 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balcazar Pust, Emilio A1 - Neher, F. A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Determination of ignition temperature in micro reactors N2 - Explosion protection of oxidation reactions in micro reactors was investigated. Lange et al. (2014) reported on the possibilities of operating oxidation reactions in catalyst coated micro reactors within the explosion regime, but also warned about hotspot induced thermal runaway and detonation ignition at certain conditions. Methane and ethene, representing the explosion groups IIA1 and IIB (DIN EN ISO 16852), were used in stoichiometric oxygen mixtures with respect to total oxidation, which represents the worst case scenario in terms of safety assessment. Using laser radiation on a ceramic target inside of the micro channel, an artificial, controllable hotspot was generated. The ignition temperatures of fuel gas/oxygen mixtures inside a micro reactor were measured and their dependencies on initial pressure, initial temperature, volumetric flow rate, and micro channel height were examined. Deflagration reactions prior to the detonation were observed for the first time inside a micro reactor. KW - Explosion safety KW - Explosionsschutz KW - Zündtemperatur KW - Mikroverfahrenstechnik KW - Thermisches Durchgehen KW - Micro process engineering KW - Autoignition temperature KW - Hotspot KW - Thermal Runaway PY - 2016 DO - https://doi.org/10.3303/CET1648092 SN - 2283-9216 SN - 1974-9791 VL - 48 SP - 547 EP - 552 PB - AIDIC CY - Milano AN - OPUS4-34164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -