Posted on 09/11/2005 8:16:41 AM PDT by grundle
http://www.sciencedaily.com/releases/2005/09/050907102549.htm
Date: 2005-09-08
Danish Researchers Reveal New Hydrogen Storage Technology
Scientists at the Technical University of Denmark have invented a technology which may be an important step towards the hydrogen economy: a hydrogen tablet that effectively stores hydrogen in an inexpensive and safe material.
With the new hydrogen tablet, it becomes much simpler to use the environmentally-friendly energy of hydrogen. Hydrogen is a non-polluting fuel, but since it is a light gas it occupies too much volume, and it is flammable. Consequently, effective and safe storage of hydrogen has challenged researchers world-wide for almost three decades. At the Technical University of Denmark, DTU, an interdisciplinary team has developed a hydrogen tablet which enables storage and transport of hydrogen in solid form.
“Should you drive a car 600 km using gaseous hydrogen at normal pressure, it would require a fuel tank with a size of nine cars. With our technology, the same amount of hydrogen can be stored in a normal gasoline tank”, says Professor Claus Hviid Christensen, Department of Chemistry at DTU.
The hydrogen tablet is safe and inexpensive. In this respect it is different from most other hydrogen storage technologies. You can literally carry the material in your pocket without any kind of safety precaution. The reason is that the tablet consists solely of ammonia absorbed efficiently in sea-salt. Ammonia is produced by a combination of hydrogen with nitrogen from the surrounding air, and the DTU-tablet therefore contains large amounts of hydrogen. Within the tablet, hydrogen is stored as long as desired, and when hydrogen is needed, ammonia is released through a catalyst that decomposes it back to free hydrogen. When the tablet is empty, you merely give it a “shot” of ammonia and it is ready for use again.
“The technology is a step towards making the society independent of fossil fuels” says Professor Jens Nørskov, director of the Nanotechnology Center at DTU. He, Claus Hviid Christensen, Tue Johannessen, Ulrich Quaade and Rasmus Zink Sørensen are the five researchers behind the invention. The advantages of using hydrogen are numerous. It is CO2-free, and it can be produced by renewable energy sources, e.g. wind power.
“We have a new solution to one of the major obstacles to the use of hydrogen as a fuel. And we need new energy technologies – oil and gas will not last, and without energy, there is no modern society”, says Jens Nørskov.
Together with DTU and SeeD Capital Denmark, the researchers have founded the company Amminex A/S, which will focus on the further development and commercialization of the technology.
The press just never gets it. Ammonia is made from....duh....natural gas.
Well, hot doggies, we can have these for breakfast, with milk poured over them and an artificial sweetener sprinkled on top.
Oh. You are supposed to pour a handful in the fuel tank of the vehicle.
And then? What are we going to do with the residue of these little tablets after the hydrogen in them is depleted?
Reminds me of a terrible movie of many years ago. Someone devised a method of storing energy on a phonograph record. All you had to do was play the record on a super phonograph to recover the energy. I don't remember anything else about the movie, I was laughing too hard.
This would definitely be a step in the right direction but there's no mention of the technology or cost of encapsulating the hydrogen. Also, if the primary source of the encapsulated hydrogen is natural gas I don't see how that helps solve the energy crisis.
Overall, an incredibly bad idea.
I bet you'd need a vehicle the size of a locomotive to (1) carry the processor that converts the ammonia tablet into hydrogen, and (2) processes the hydrogen to provide energy to drive the vehicle.
/daydream
Even if you can catalyze ammonia to yield hydrogen and nitrogen, this still smells like snake-oil.
Ammonia NH3 is made from many sources as is methane and natural gas.
I seem to remember a "gas pill" episode of the Stooges, or was it Laurel & Hardy?
You will expend much energy. Thermodynamics rules!
> The press just never gets it. Ammonia is made
> from....duh....natural gas.
Usually. Plus there's the buring question about burning
the resultant H2. If the oxidizer is air, there will also
be NOx by-products.
Plus, any "real"(TM) enviro-wacko will complain that the
system can't be 100% efficient, and the lost energy is
"heat pollution".
Ammonia (NH3) combines readily with a number of different compounds, and can exist as a liquid at ambient temperatures if retained under pressure. Apparently this technology of sending it over a catalyst to form free hydrogen and nitrogen, in order to power fuel cells, may be workable, but still a bit awkward in application.
In fact, the "exhaust" of this process will be three parts of N2 gas with one part of H2O, and since some 78% of our atmosphere is ALREADY free nitrogen, the additional N2 cannot be considered a pollutant. The side reaction, the formation of nitrogen oxides, is relatively minor, and may not proceed to any significant degree at all. Nitrogen combines with oxygen only extreme conditions of heat and/or pressure (Lightning bolt or inside an internal combustion engine), so this objection could be discounted for the purposes of operating a fuel cell.
That still begs the question of how the ammonia is produced in the first place. There ain't no free lunch.
I did say the method, though workable, is awkward.
Ammonia is one of the components of natural gas (perhaps one the order of less than 1%, as is water, and combines readily with the water, forming an unstable compound, NH4OH, a volatile alkaline substance that may be separated from the methane, ethane, propane and butane in the natural gas mixture.
The ammonia is recovered by collection in a fractionation column, after being sufficiently cooled and while under pressure (Boyle's law). The butane, propane, and water have all liquified or even become solid at this point. I am not sure at what temperture ammonia becomes a liquid, but certainly it is higher than ethane or methane. When liquid it is drawn off.
Hydrogen as a motor fuel is a distant dream. More likely is the conversion of most vehicles to methane fueling, which is then used to be reformed into hydrogen and used in the fuel cells. Or the methane could be burned directly in an internal-combustion engine.
And where is all this methane going to come from? Glad you asked. Vast quantities of a substance called Methane Hydrate lie about on the ocean floor, an amorphous substance that resembles ice, and is stable at temperatures below 38º Fahrenheit. Scoop up these deposits of Methane Hydrate, let them warm slightly to about 42º Fahrenheit, and presto! The methane trapped in this mixture is released, giving up something like 168 times its volume in methane gas, which is immediately available for reformulating into other petroleum products.
Capturing and processing Methane Hydrate is probably no more risky than deep off-shore drilling for petroleum or natural gas, and should present few hazards we are not already familiar with.
Douse 'em in ammonia and they 'recharge', just like the article says.
Yes, but will the FDA approve it?
The hydrogen economy is bullsh*t until there is a way to economically produce, store and distribute the stuff. Reforming methane ain't it.
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