Hydrogen Storage

By Michelle Delepine

CH 407H

Several options

Metal Hydride Tanks

Compressed Hydrogen

Liquid Hydrogen

Chemically Stored Hydrogen

Carbon Nanotubes

Glass Microspheres

Metal Hydride Tanks

Metallic alloy

Absorb H and release later Room temp or heat

Metal Hydride Tanks

Pros Cons SafeConstant pressurePurifies HNo escape potential

Life related to purity• Impurities fill tank

Small relative capacity • 1-2% of weight• 5-7% in 250° C

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Compressed H

H is compressed into high-pressure tank

Tank material: aluminum or carbon/graphite compounds

Liners have reduced leakage

Compressed H

Pros Cons High energy density Simple design

Occupies a large space Would have to be 3,ooo times larger to store as much energy as a gasoline tank Compression ($) Held at higher pressures for larger scales of use High escape potential Safety checks: Seals

Liquefied H

Insulated

Reinforced

Liquefied H

Pros Cons Can hold more in less volume than can compressed H More energy per mass than gasoline

Needs -253°C Compression and cooling ($)Energy net loss 30% Large tank for insulation Safety (Escape potential)

Depends on tank integrity and temperature

Chemically stored H

Chemical reaction combines H into stable compound

Release H with second reaction

Chemically Stored H

Pros Cons Most abundant element Found in numerous chemical compounds

Can use various compounds

Doesn’t need storage tankProduced on demand

Ammonia cracking Methanol cracking Partial oxidation

H cannot be released

Can be bulky and heavy if stored

Carbon nanotubes

Microscopic carbon tubes (2 nanometers dia)

Store H on microscopic pores

Similar to metal hydrides

Carbon nanotubes

Pros Cons Store 4.2-65% of weight Refuel after 5000 km

Cannot be placed in predetermined positions during manufacturing Cannot control electrical properties

Glass microspheres

Tiny hollow glass spheres

Warming H gas

Cooling locks H inside

Warming releases H

Glass microspheres

Pros Cons Can be very safe Resist contamination Can be stored at low pressure

Glass breakage

References makes glass permeablereleases H Filled by immersing in high-pressure

http://www.e-sources.com/hydrogen/storage.htmlhttp://www.nanodot.org/article.pl?sid=02/08/23/0444204http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/25106.pdfhttp://www.eere.energy.gov/hydrogenandfuelcells/storage/compressed_gas.html