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How to store hydrogen at low pressure? Answered


What is the most practical and cost efficient way to make a 10m3 gas bag for the storage of hydrogen?

I am planning to store pure Hydrogen (made from water electrolysis) in an outdoor area, a bit like the way biodigestor gas is stored in low cost, small scale installations.

My concern is the high effusing nature of the gas through membrane material. My first thought was to use reinforced PVC like that used for truck tarpaulins but I can't find any info on effusing rates verses other materials. Ideally the gas would be able to remain in the bag for a maximum 2-3 weeks until needed.

This is an experiment on the practical applications of locally produced hydrogen, so I hope to be able to follow up any advice by constructing the gas bag and reporting back with the project progress. Any thoughts and advice would be gratefully received!
Thanks in advance,
Nick

Discussions

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Nick 73

2 years ago

Having spent the past few years researching alternative energy I understand only too well the safety protocol and respect hydrogen requires, so I appreciate your advice and safety pointers to check local laws which I will look into. I posted the question here because I love the website and am always inspired by reading about so many inventive and original ways of making stuff and solving problems! So I thought there might be some out of the box ideas out there that I hadn't some across or considered. I checked out the Red Bull Stratos and was surprised to learn the helium balloon is made of polyethylene - plastic bags! Many thanks everyone!

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QuadrifoglioNick 73

Answer 2 years ago

Raven Industries http://ravenind.com/2012/10/24/raven-industries-su... supplied the Red Bull Stratos balloon. They are also a high tech blown film company. So although they joke about the balloon being "dry cleaning bags", I suspect it is a bit more complex than that.

Also, just a word of caution in regard to inflation and deflation. Everyone understands that a flexible containment system moves. What is not generally understood is that, if the membrane is too stiff, the membrane can create ridges or points. The ridges and points can abrade or work harden and fracture. Either results in a hole. See below for flaming, run screaming, oh the humanity warnings.

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rickharris

2 years ago

OK last suggestion not withstanding all the previous doom and gloom warnings. I guess you could store it in any kind of vessel - e.g a metal tank if the tank were filled with water and the opening held under water allowing the hydrogen to displace the water.

just the same way you would collect it in a lab in a test tube.

No liability though things could still go badly wrong. You most definitely do this at your own risk.

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Nick 73

2 years ago

Hi all,

Thanks for your suggestions and advice. Just to add that this not a permanent installation and just a one off test. I'm a PhD researcher and am getting advice from engineers on the project - we have developed a good understanding of the necessary safety protocol, so I'd be really grateful if any advice focuses on the question of the ideal material for the hydrogen storage. Many thanks and look forward to following up any more suggestions!

Nick

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QuadrifoglioNick 73

Answer 2 years ago

I understand the point steveastrouk is making and it is a good one, hydrogen is inherently dangerous. Especially if a solution is “cowboyed up” just to keep it cheap. Around here, such events are usually preceded by “Hey everybody, watch this!” That is a clear signal to retreat to a safe distance. Kinda like deep frying a frozen turkey https://www.youtube.com/watch?v=6MR-2zKnn1I.

However, if you look at LEL and UEL, there are lots of gasses that are close to or lower than the LEL for hydrogen. And yes, hydrogen has a high UEL, but so does ethylene oxide. We pump gasoline into our cars knowing that one cup of vaporized gasoline can blow the trunk open. We even park them in attached garages. We have methane and propane pumped into our homes despite houses fairly regularly being reduced to kindling by gas leaks. People still use “starter fluid”.

http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html

The key here is that there are accepted, mature technologies for safely handling flammable gasses/liquids. And yes, even the safeguards can fail, but it is far less likely. Practical hydrogen has safeguards and in part it is compressing it into pressure rated tanks for storage. Even the “off the gridders” are using it this way. Safety does have a cost and is ignored at risk.

However, A. not endorsing your handling of flammable materials and B. not making any recommendations, due to obvious liability issues, pursuing weather balloons (recommended by rickharris and probably the best answer you will get here) or high altitude lifting balloon construction like the Red Bull Stratos are where you would probably have the best luck.

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QuadrifoglioQuadrifoglio

Answer 2 years ago

CORRECTION - that should have said suggested by rickharris, not recommended.

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rickharrisNick 73

Answer 2 years ago

1. It helps if you tell us everything that may be applicable.

2. If your a Phd researcher - do your own research.

3. I can't beleive your principles or Health and Safety will allow you to do this.

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steveastroukNick 73

Answer 2 years ago

I'm sorry. Have your "engineers"' explained at length the incredibly LEL for H2 and the wide band of EL that it's dangerous over ? Have you got proper calculations of the potential explosive potential of 10m^3 of H2, constrained in what appears to be little more than a garbage bag ? There is, in a stoichometric burn 100,000,000 Joules. That is one god awful amount of energy.

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Downunder35m

2 years ago

I agree with Rick, before you proceed check local laws.
In your amount most councils (if they allow it at all) will require you to only use tested equippment installed by a licensed pro.
Even if you go costly and use a compressor and cooling to store the gas in proper pressure cylinders you might need a special permit to do so in your area.
Something going wrong with your hobby setup means you can loose your life twice.
Either through direct combustion or by paying off the costs for repair, court, fire brigade and so on....