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

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

3. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Why recombiners ? Device removing hydrogen from oxygen containing atmosphere (e.g. air) in the presence of a catalyst (e.g. Pt, Pd)hydrogen sink Today application in areas where venting is not sufficient/possible - NPP containment (H 2 formation during core melt accident) - BWR cooling circuit (H 2 formation in operation) - submarines (H 2 released from the propulsion system) - batteries (‚HydroCaps‘) specific applications Future use of hydrogen in ‚any‘ surrounding may lead to an extended area of application for recombiners

4. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft catalyst sheets Siemens design Catalytic recombiners in NPP Severe accident in LWR  H 2 release Formation of flammable H 2 /air mixture inside containment Installation of catalytic recombiners

5. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft PAR principle inlet H 2 + air outlet air + H 2 O catalyst H 2 + ½ O 2  H 2 O + heat inlet H 2 + air outlet air + H 2 O catalyst H 2 + ½ O 2  H 2 O + heat chimney buoyancy effect natural convection application forced flow application

6. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Catalyst temperatures - major drawback 0 100 200 300 400 500 600 700 800 0123456 inlet hydrogen concentration / vol.% max. catalyst temperature / °C conventional ignition temperature plate-type catalyst mesh-type catalyst

7. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 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

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

9. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 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

10. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 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 HPC-LS APC-LS HPC-PC catalyst design, support design geometrical design, cooling elements

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

12. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Experimental Facilities

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

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

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

16. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Performance of HPC and APC H 2 concentration / vol.% catalyst temperature / °C 1.0 m/s 0 200 400 600 800 1000 1200 0510152025 HPC-LS APC-LS

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

18. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Performance of new HPC-LS approach 250 300 350 400 450 500 0246810 H 2 concentration / vol.% catalyst temperature / °C 50 60 70 80 90 100 efficiency / % catalyst temperature efficiency flow rate: 0.25 m/s support: plate-type catalyst: n-Pt MO

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

20. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft Performance of HPC-PC diameter 8 mm 0,5 m/s 0 100 200 300 400 500 600 024681012 hydrogen concentration / vol.% catalyst temperature / °C HPC-PC HPC Passive cooling support approach: passive cooling by means of heatpipes

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

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

23. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 5% H 2 in air system temperature 10 % 0% 5% 0% H 2 in air HPC T0T0 T max hydrogen concentration Medium inlet H 2 concentration high outlet temperature

24. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 5% H 2 in air system temperature 10 % 0% 5% 0% H 2 in air HPC PC T0T0 T max hydrogen concentration Medium inlet H 2 inlet concentration low outlet temperature

25. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 10% H 2 in air system temperature 10 % 0% 5% 0% H 2 in air APC HPC PC T0T0 T max hydrogen concentration High inlet H 2 concentration low outlet temperature

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

27. Forschungszentrum Jülich in der Helmholtz-Gemeinschaft 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

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