Liquid Hydrogen Storage: Status and Future Perspectives

1 Liquid Hydrogen storage : Status and Future Perspectives Hendrie Derking, Luuk van der Togt & Marcel Keezer Cryoworld BV. Cryoworld BV. Design, Engineering, Simulation, Manufacturing, Installation and Testing of high-end cryogenic systems for Liquid helium, Liquid Hydrogen and other liquefied gases. Liquid Hydrogen storage : Status and Future Perspectives CHMT'19 November 4th, 2019 2. H. Derking Outline Why Hydrogen ? Why Liquid Hydrogen ? Design of Liquid Hydrogen storage tanks Performance of existing Liquid Hydrogen storage tanks Road to high performance Liquid Hydrogen storage tanks CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 3. November 4th, 2019 H. Derking Why Hydrogen ? 140. Energy density - MJ/kg 120. Reducing fossil fuels 100. 80. Very high energy density 60. 40. High potential for transportation, 20. energy carrier and energy storage 0. Green production when using renewable energy sources Renewable energy sources Power Solar excess power Water H2.

2 Wind electrolysis Geothermal consumed power Hydraulic Biomass CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 4. November 4th, 2019 H. Derking Hydrogen transportation potential Picture: Toyota Picture: BMW. Hydrogen Picture: ESA/CNES/ArianeSpace Picture: Hyundai Picture: Sandia National Lab Picture: Airbus Picture: Toyota CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 5. November 4th, 2019 H. Derking Hydrogen storage Gaseous storage Liquid storage Solid storage Pressurized to 700-900 bar At atmospheric pressure Physisorption in porous materials storage at room temperature storage at K Adsorbed on metal hydrides In slush to increase density Complex compounds Metals and complexes with water Density kg/m3. 80. 70. 60. 50. 40. 30. 20. 10. 0. CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 6. November 4th, 2019 H. Derking Liquid versus high-pressure gas storage Liquid storage High pressure gas storage Density kg/m3 @ 1 bar, K 39 kg/m3 @ 700 bar, 293 K.

3 Safety Low pressure system with low enthalpy Huge amount of potential energy Spill can lead to floor accumulation Spill can lead to jet Intrinsically safe due to vacuum jacket No safety barrier Boil-off Energy needed ~12 kWh/kg for liquefaction ~ 6 kWh/kg for compression big expensive system small less expensive system boil-off during no use No loss during no use Handling Liquid to Liquid : by pumping or by Gas to gas: pressure will balance gravity Liquid to HP gas: by efficient pumping Slow filling Very fast filling Complex logistics Simple logistics storage Single tank Long thick walled cylinder bundles Cost of storage 300 / kg 900 / kg system Long lifespan Relatively short lifespan CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 7. November 4th, 2019 H. Derking Liquid Hydrogen storage tanks Aviation Ground-based Relatively small tank size Large tanks Low weight Weight not very important Non-vacuum insulated Vacuum-insulated Higher evaporation could be Zero boil-off accepted Materials Aluminium alloys Composites Fibre reinforced polymers CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 8.

4 November 4th, 2019 H. Derking Liquid Hydrogen storage tanks Picture: Linde Picture: NASA Picture: Kawasaki Picture: Linde NASA, 3800 m3 , 270 t JAXA (Kawasaki), 540 m3, 38 t Boil-off ~12% H2 LH2 truck, < 50 m3, < t Largest storage tanks constructed for space applications. Spherical shape to optimize surface area to volume ratio. Most tanks made with perlite insulation. Boil-off rates of 1 - 5% / day. CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 9. November 4th, 2019 H. Derking Heat flow into Liquid Hydrogen storage tank Insulation: radiation, convection, conduction Conduction through support system low thermal conductivity materials high strength materials Conduction through interconnecting piping system Small cross-section (thin walled pipes). Increase length Radiation from warmer parts of the container Shield by using baffles Optimize design, avoid direct view to warm parts Natural convection in vapour above Liquid due to heating Ortho-para conversion CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 10.

5 November 4th, 2019 H. Derking Optimizing heat flows No boiling takes place! All heat entering the Liquid is absorbed primarly by convection. Two types of heat flows A: heat flows adsorbed in the Liquid resulting in evaporation of the Liquid B: heat flows adsorbed in the cold vapour. With good design, B heat flows may not contribute to the evaporation at all. Minimize A heat flows and ensuring adsorbing B. heat flows in cold vapour. CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 11. November 4th, 2019 H. Derking Ortho-para conversion 100. 96%. 90. H2 H2 80. 70. Percentage [%]. released energy 60. 50 parahydrogen Ortho Para 40. 30. In equilibrium: 20. 10. 25% para-H2 / 75% ortho-H2 at RT 0. 50% para-H2 / 50% ortho-H2 at 77 K 0 50. 77K. 100 150 200 250 300. Temperature [K]. para-H2 / ortho-H2 at 20 K. Energy released during full conversion at 20 K is ~670 kJ/kg.

6 A catalyst ( Iron(III) oxide) is used to during liquefaction to speed up the transition. A small part (~4%) of released energy still will be adsorbed in Liquid . CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 12. November 4th, 2019 H. Derking Insulation k-value (300 77 K). Insulation type Examples [mW/mK] + - Insulation@atm Foams ~20 - 50 Low weight High heat load pressure Powders Relatively cheap Need constant purging Solid fibres Easy to produce Silica aerogels Perlite @ 10-2 mbar ~ Standard Needs strong vacuum enclosure technology Heavy structure Good performance Multilayer insulation Excellent Needs strong vacuum enclosure (MLI) @ 10-4 mbar performance Heavy structure Most expensive solution CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 13. November 4th, 2019 H. Derking Current Status Picture: Linde Most tanks made with perlite insulation, using LN2 technology.

7 Boil-off rates of 1-5% / day. Why LN2 based storage tanks? Picture: Kawasaki - Experience from the past, standard product;. - Latent heat of H2 is very high. Liquid @ 1 bar abs. Latent heat Temperature / mass [K] [kJ/kg]. Hydrogen JAXA (Kawasaki), 540 m3, 38 t Nitrogen Methane Helium CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 14. November 4th, 2019 H. Derking Reducing boil-off The density of H2 is very low, resulting in a low volumetric latent heat! To reduce the boil-off rate it would be better to use LHe technology: - Multi-layer insulation in combination with high vacuum;. - Actively cooled radiation shields. Liquid @ 1 bar abs. Latent heat Latent heat Factor of Temperature / mass Density / volume LH2. [K] [kJ/kg] [kg/m3] [kJ/m3] [-]. Hydrogen 31828 Nitrogen 160769 Methane 215933 Helium 2604 CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 15.

8 November 4th, 2019 H. Derking Two examples Large LHe storage @ CERN. - Volume:4 x 120 m3. - Boil off: ~ g/s or Small LHe storage @ CERN. - Volume: 5 m3. Conversion to LH2 - Boil off: ~ g/s or - or g/s Picture: CERN. Conversion to LH2. - or g/s CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 16. November 4th, 2019 H. Derking Conclusions Due to high liquefaction costs, zero boil-off should be the goal for all Liquid Hydrogen storage tanks. Currently, most ground -based Liquid Hydrogen storage tanks have perlite+vacuum insulation without active shielding, resulting in boil-off rates of 1-5%/day. Boil-off could be reduced to by using storage tanks based on LHe technology (MLI insulation and active shielding). In case of large storage tanks, boil-off gas could be re-liquefied to reach zero-boil off. CHMT'19 Liquid Hydrogen storage : Status and Future Perspectives 17.

9 November 4th, 2019 H. Derking Thanks for your attentio