Intro: Soda Can Hydrogen Generator for Alternative Energy
Make Hydrogen On Demand from Activated Aluminum and Water.
This invention has been patented!
I use a drop of liquid metal that I bought from eBay and aluminum from a soda can to produce hydrogen from water.
This reaction solves the problem of hydrogen storage for the hydrogen economy. Energy dense activated aluminum acts as the storage medium, liberating hydrogen on demand when exposed to water.
After the exhaustion of the reaction, the resultant aluminum oxide (alumina) is shipped to a power generator plant that reduces it back to aluminum. Since alumina is a suspension in water it can be delivered via pipelines to the power station.
Liquid metal is available here:
It is usually listed on the internet as
Coollaboratory LiquidPro Fluessigmetall Waermeleitpaste
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Step 1: Prepare the Aluminum
Cut the soda can into strips.
Sand the plastic off a strip.
The finished strip should be clean and shiny.
Proceed swiftly to step 2.
Step 2: Activating the Aluminum Strip
Add a drop of liquid metal (I got mine on eBay.)
Smear the liquid metal on the shiny aluminum surface.
When the liquid metal "wets" the aluminum surface, the strip is ready.
I sort of stir the liquid metal on top the aluminum, scratching the aluminum beneath.
The aluminum is wetted when the liquid metal sticks to the surface.
The idea is that gallium stops the aluminum from forming an oxide layer.
When aluminum gets in contact with water usually nothing happens because the oxide layer acts as a buffer. When the oxide layer is scrapped off aluminum, a new layer rapidly forms preventing any reaction.
Liquid metal is an alloy of gallium, indium, and tin so it acts as a source of gallium. Liquid metal is non-toxic (but I advice against injecting yourself with liquid metal... just in case that crosses your mind).
Step 3: The Reaction
Drop the activated strip in water. Watch the aluminum as it is converted into alumina and hydrogen bubbles off.
the reaction is 2Al + 3H2O --> 3H2 + Al2O3 + heat
Collect the hydrogen to run your car.
Step 4: Recovery of Liquid Metal
Initially, I used to filter the alumina and squeeze the liquid metal out. Obviously some remained in the Alumina cake.
So I dissolved the alumina in a solution of NaOH, caustic soda, (you can use Drano). The liquid metal precipitated immediately.
This shows almost 100% recovery of liquid metal which makes this type of reaction economically sustainable.
In the hydrogen economy, separation of the gallium will be done at the power plant. The alumina is reduced back to aluminum using the Hall-Heroult process. The first aluminum plant in history was powered by the Niagara falls, a green source of energy.
However, this instructable can be scaled for individual use. The amount of gallium to proceed the reaction is small and recoverable. Ardent green energy enthusiasts can run their car and home using this instructable.
Step 5: UPDATE
Ironsmiter turned my attention to the fact that transporting mercury in aircraft was a danger to their aluminum structure. He referred to a pop-sci article titled "The Amazing Rusting Aluminum". Apparently mercury can "rust" aluminum in a few hour.
So i decide to test if the same happens with liquid metal.
I placed a drop on the bottom of the soda can and left it in the open air. It made a little grey fuzz on it's surface. Nothing spectacular happened, unlike mercury. That was two days ago.
I inspected the drop today and I COULD NOT FIND IT! IT LOOKED LIKE IT DRIED UP! Metal drying up, go figure! but there was a large blotch on the aluminum.
I added a little bit of water and the thing went INSANE! It bubbled like a volcano. There was so much heat the water dried up!
The reaction was much more violent then freshly applied liquid metal!
Step 6: UPDATE: Slow Corrosion of Aluminum by Liquid Metal (Galinstan)
I left an activated soda can bottom for at least three month. While I was cleaning the laboratory I rediscovered the can and to my surprise the bottom has disintegrated into a gray dust. I am puzzled by this, but it looks like liquid metal (Galinstan) does corrode aluminum like mercury but at a very slow rate, on the order of months compared to hours with mercury.
The last pictures shows what happens when mercury reacts with aluminum.
Step 7: HydroPak Water-activated Portable Power Generator
In January 2008 Millennium Cell Inc. and Horizon Fuel Cell Technologies had announced the completion of a pre-production version of the HydroPak portable power generator.
The HydroPak product combines Horizon's fuel cells with Millennium Cell's Hydrogen on Demand storage technology. The Hydrogen on Demand storage technology, or HOD systems, is in a form of a dry cartridge. Hydrogen on Demand utilizes sodium borohydride (NaBH4) as a hydrogen storage medium. It offers infinite shelf-storage life and 400 Watt hours of "instant power" by just adding water.
The HydroPak provides the power through a common AC outlet and two USB connectors allowing low power devices to operate for more than 16 hours when the electrical grid is unavailable.
Millennium Cell Inc.
Horizon Fuel Cell Technologies
Step 8: Icelandic Aluminum Batteries
Dr. Pieter van Pelt proposes charging Aluminum batteries from cheap green energy produced in Iceland. Then the batteries are shipped to any location in the world and discharged in a power grid. The empty batteries go back to Iceland for recharging. Here's the logic:
Aluminum batteries "are being developed by Europositron in Finland. They claim the following specifications for their technology:
Energy density : 2100 W.h/litre or 1330 W.h/kgr
Cycle times : 3000+ cycles
Working temperatures : -40 C to +70 C
Lifetime battery : 10 to 30 years
Let's assume, we equip a large ship with 200 giant batteries, each the size of a 40 foot shipping container. Each battery will weigh about 220 tons, so a 50,000 BRT ship can carry these. The batteries are charged fully in Iceland, making use of cheap electricity from hydropower or geothermal power. The 200 batteries will contain about 50 GW.h electricity when fully loaded. The ship (electrically powered of course) sails to the west coast of Denmark or England, or to the East coast of the USA. There it delivers its electrical charge into the national grid, but it keeps some batteries charged for the return trip to Iceland. It sails back and charges again. It can do so 3000 times before the batteries are worn out and must be replaced. A simple calculation shows that the electricity can be delivered at the end market for a very low price, roughly 20 to 25 Euro per MW.h (substantially below residential rates of 45 to 50 Euro per MW.h). The trick is, of course, that large quantities of hydropower or geothermal power in Iceland are very cheap (roughly 12 to 15 Euro per MW.h), that transportation of bulk goods over sea is very cheap (hence the economy of processing bauxite ore from New Zealand in Iceland to make Aluminum ingots), and the large investment in Al-batteries has an extended lifetime (3000 or more cycles). "