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Design Studies of Catalytic Recombiners for Hydrogen Safety

This study focuses on the design and implementation of catalytic recombiners for safe hydrogen removal from flammable gas mixtures. It covers design principles, operation, and future applications of recombiners in various settings.

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Design Studies of Catalytic Recombiners for Hydrogen Safety

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  1. E.-A. Reinecke, S. Kelm, S. Struth, Ch. Granzow, U. Schwarz* Institute for Energy Research - Safety Research and Reactor Technology (IEF-6)*Institute for Reactor Safety and Reactor Technology RWTH Aachen University • Catalytic recombiners • Design studies • Conclusions Design of catalytic recombiners for safe removal of hydrogenfrom flammable gas mixtures 2nd International Conference on Hydrogen SafetySan Sebastian, September 11-13, 2007 Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  2. Severe Accident Research NETwork (NoE) (EURATOM) Safety of Hydrogen as an Energy Carrier (NoE) Research on hydrogen safety at FZJ • Focus: H2 removal by means of catalytic recombiners (PAR) • Hydrogen laboratory with 3 REKO facilities experimental PAR studies • Service of Dpts. Analytical Chemistry (ZCH) and Technology (ZAT) catalyst development • Simulation of recombiner behaviour code development Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  3. Why recombiners ? • Device removing hydrogen from oxygencontaining atmosphere (e.g. air) in thepresence of a catalyst (e.g. Pt, Pd) hydrogen sink • Today application in areas where venting is not sufficient/possible- NPP containment (H2 formation during core melt accident)- BWR cooling circuit (H2 formation in operation)- submarines (H2 released from the propulsion system)- batteries (‚HydroCaps‘) specific applications • Future use of hydrogen in ‚any‘ surrounding may lead to anextended area of application for recombiners Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  4. 200 model: conversion rate related to theinlet cross-section FR90-1500 FR90-320 150 source: Siemens PAR information FR90-960 100 H2 conversion rate in n-m³/(m²h) catalystsheets model: FR90-320 50 Siemens design source: BMC experiments 0 0 3 6 9 H2 concentration in vol.% Catalytic recombiners in NPP • Severe accident in LWR  H2 release • Formation of flammable H2/air mixture inside containment • Installation of catalytic recombiners Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  5. PAR principle outlet air + H2O chimney buoyancy effect inlet H2 + air catalyst H2 + ½ O2 H2O + heat outlet air + H2O catalyst H2 + ½ O2 H2O + heat inlet H2 + air natural convection application forced flow application Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  6. Catalyst temperatures - major drawback 800 700 600 conventional ignition temperature 500 plate-type catalyst 400 max. catalyst temperature / °C mesh-type catalyst 300 200 100 0 0 1 2 3 4 5 6 inlet hydrogen concentration / vol.% Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  7. Challenge • Passive system temperature control • no direct influence on the process parameters(flow rate, inlet mixture composition, active temperature control) • no active cooling • Further demands • resistance against catalyst poisoning/deactivation • environmental influences depending strongly on application self-regulating system Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  8. Design studies • Catalytic recombiners • Design studies • Conclusions Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  9. Self-regulating system • General approach • local limitation of the catalytic reaction • passive cooling of the catalyst elements catalyst design, support design geometrical design, cooling elements Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  10. Self-regulating system • General approach • local limitation of the catalytic reaction • passive cooling of the catalyst elements • Basic element types (catalyst - support) • high performance catalyst - large surface support • adapted performance catalyst - large surface support • high performance catalyst - passive cooling support catalyst design, support design geometrical design, cooling elements HPC-LS APC-LS HPC-PC Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  11. Experimental Facilities • Experimental studies on the operational behaviour under well defined conditions Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  12. Experimental Facilities Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  13. Experimental Facilities • REKO-1 • Experimental studies on reaction kinetics in catalyst elements • Substrates applied- steel meshes- ceramic bodies Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  14. REKO-1 test facility gas analysis pyrometer thermocouples catalyst samples inlet Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  15. Realisation of large surface support Pt - washcoat • Large surface support • high performance catalyst • adapted performance catalyst Pt - electroplated Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  16. APC-LS Performance of HPC and APC 1200 1000 HPC-LS 800 catalyst temperature / °C 600 400 200 1.0 m/s 0 0 5 10 15 20 25 H2 concentration / vol.% Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  17. Realisation of APC-LS - new approach Pt-nano-particles / metal oxide matrix • APC-LS • adapted performance catalyst • large surface support Ceramic cell support Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  18. Performance of new HPC-LS approach 500 100 catalyst temperature 450 90 efficiency 400 80 catalyst temperature / °C efficiency / % 350 70 300 60 flow rate: 0.25 m/s support: plate-type catalyst: n-Pt MO 250 50 0 2 4 6 8 10 H concentration / vol.% 2 Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  19. Realisation of passive cooling • Passive cooling support • approach: passive cooling by means of heatpipes Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  20. Performance of HPC-PC 600 • Passive cooling support • approach: passive cooling by means of heatpipes HPC 500 400 catalyst temperature / °C 300 HPC-PC 200 100 diameter 8 mm 0,5 m/s 0 0 2 4 6 8 10 12 hydrogen concentration / vol.% Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  21. Basic features of catalyst designs type catalyst support start behaviour efficiency/ element thermalbehaviour HPC-LS high performance large surface ~ 2 vol.% ~ 70 % unlimitedheating up APC-LS adapted performance large surface < 1 vol.% > 90 % limited to~ 450°C HPC-PC high performance passive cooling ~ 2 vol.% ~ 10 % limited to~ 200°C Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  22. Basic features of catalyst designs type catalyst support start behaviour efficiency/ element thermalbehaviour HPC-LS high performance large surface ~ 2 vol.% ~ 70 % unlimitedheating up APC-LS adapted performance large surface < 1 vol.% > 90 % limited to~ 450°C HPC-PC high performance passive cooling ~ 2 vol.% ~ 10 % limited to~ 200°C • Modular set-up of different elements - examples • medium H2 amount - high acceptance level for PAR temperature • medium H2 amount - low acceptance level for PAR temperature • high H2 amount - low acceptance level for PAR temperature Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  23. Medium inlet H2 concentration high outlet temperature HPC 0% H2in air 5% H2in air 10% 5% hydrogen concentration 0% Tmax system temperature T0 Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  24. Medium inlet H2 inlet concentration low outlet temperature PC HPC 0% H2in air 5% H2in air 10% 5% hydrogen concentration 0% Tmax system temperature T0 Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  25. High inlet H2 concentration low outlet temperature PC APC HPC 0% H2in air 10% H2in air 10% 5% hydrogen concentration 0% Tmax system temperature T0 Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  26. Conclusions • Catalytic recombiners • Design Studies • Conclusions Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  27. Conclusions • PAR can reduce the explosion risk in future hydrogen applications • Challenge: high efficiency at system temperatures below the ignition limit • Approach:- adaptation of the catalyst activity- passive cooling elements • Different types of catalyst elements have been identified and investigated • Modular set-up in order to adapt the PAR operation behaviour to the boundary conditions of the application Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

  28. The end THANK YOU FOR YOUR ATTENTION ! Forschungszentrum Jülich in der Helmholtz-Gemeinschaft

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