Self-Sustaining Solar Reactor Creates Clean Hydrogen 406
An anonymous reader writes "A mechanical engineer working out of the University of Delaware has come up with a way to produce hydrogen without any undesirable emissions such as carbon dioxide. The solar reactor is capable of using sunlight to increase the heat inside its cylindrical structure above 3,000 degrees Fahrenheit. Zinc oxide powder is then gravity fed through 15 hoppers into the ceramic interior where it converts to a zinc vapor. At that point the vapor is reacted with water separately, which in turn produces hydrogen. If the prototype gets through 6 weeks of testing at the Swiss Federal Institute of Technology located in Zurich, we could see it scaled up to industrial size, producing emission-free hydrogen."
How down-scalable is it? (Score:5, Interesting)
Comment removed (Score:5, Interesting)
Re:How down-scalable is it? (Score:5, Interesting)
It seems to me that as an energy storage medium (and that's what it is, it's not a fuel "source") Hydrogen would lose out to a plain old chemical battery when all it needs to do is sit in your basement. One of the primary pitfalls of a battery is weight and size, but that won't much matter if you just dig a deeper hole in the ground and never move it.
Anyways, going Solar -> Hydrogen -> Electrical sounds a lot more complected (not to mention inefficient) than just Solar -> Electrical.
But is it really emissions-free? (Score:5, Interesting)
Re:Darn that dirty hydrogen (Score:5, Interesting)
Clean in this context probably refers to not requiring fossil fuels.
Apparently the Zink Oxide is recoverable as well:
As well as a lack of emissions, the other good news is that the zinc oxide can apparently be reused, meaning the solar reactor is theoretically self sustaining as it only relies on materials and energy that are renewable.
although it isn't spelled out how that is performed, or if any processing is required, and if so, at what cost.
To heck with scaling this up. Lets scale it down so I can have one in my back yard, or at every corner gas station. A small reactors working any time there is sunlight and water scaled just large enough to keep your car topped off makes a lot more sense than trucking hydrogen around. Especially if the zink oxide recovery can be built in.
Then maybe hydrogen cars can become a realistic option rather than the proof of concept models and conversion kits for fleet vehicles.
Re:Darn that dirty hydrogen (Score:5, Interesting)
Hydrogen stored under pressure has a considerably lower energy density compared to hydrocarbons that we use. Hydrogen is great when you look at the energy by weight, but if a tank is sitting in the back of a car, it doesn't matter whether it weighs an extra twenty kilos, what matters is how far a tank can make a car drive.
Like I said, don't get me wrong, I think it is a fantastic breakthrough to have - a cheap, clean and sustainable way to make Hydrogen gas, but a lot of work still needs to be done before we can all whizz around in clean cars and certainly before we have large scale power stations powered by burning Hydrogen.
Having said that, burning Hydrogen makes water, this process turns water into Hydrogen. It would make for a wonderful closed circuit...
not any more, read about formic acid (Score:5, Interesting)
it can be stored in vast quantities in the form of formic acid and then released and restored in a continual cycle. there is obviously efficiency losses but apparently its very practical as it allow storage of large amount of hydrogen at a very high density in a room temperature atmospheric pressure liquid,
that is basically as safe as vinegar.
I was thinking this clean hydrogen would be perfect in so many parts of the world where their is plenty of sunlight but the land is otherwise of low value.
ps: its the nail polish like odor that gets released when ants die, and more specifically when they get crushed. its probably something they are sensitive to, so hopefully our green cars in the future dont get covered with ants in because of the pheromone.
Re:Darn that dirty hydrogen (Score:5, Interesting)
Eh? Those have nothing to do with each other. Hydrogen storage is a pain because of density and sealing. At STP, hydrogen is a very low density gas. To get decent energy density out of it, you either have to compress it to ridiculously high pressures, or chill it to ridiculously low temperatures. Di-atomic hydrogen gas molecules are about the smallest molecules that exist. They will leak through anything. A seal which is water-tight and air-tight is not necessarily hydrogen-tight. Couple this with high pressures and you have a major storage PITA.
Unless we discover some sort of hydrogen sponge which soaks up H2 gas and easily holds it at an energy density competitive with batteries and chemicals, I really doubt the hydrogen economy will take off. OTOH if someone can tweak this process so it can convert CO2 + 2 H2O ==> CH4 + 2 O2, then we have a winner. Methane, while not as ideal for storage as a liquid hydrocarbon (most oil wells and refineries just burn it off rather than try to capture and store it), is much easier to work with than H2 gas and has nearly 4x the volumetric energy density.
Long-term, I think alcohol biofuels will win out. Alcohol is nearly as good a storage medium as gasoline/diesel. First you use photosynthesis to create sugar: CO2 + H2O + sunlight ==> O2 + (CH2O)n. Plants are basically made of really long sugar molecules (cellulose). You then ferment the sugar to create alcohol: (CH2O)n ==> C(n)H(2n+1)OH. At some point we'll probably figure out a way to go straight from the raw ingredients (CO2 + H2O + sunlight) to alcohol, at which point you're converting solar energy straight into liquid fuel.
Re:Darn that dirty hydrogen (Score:5, Interesting)
Or even use the hydrogen in a Carbon-monoxide/dioxide capture scheme and produce methanol that could be used in today's engines with minor conversions.
The cars would of course re release that carbon dioxide when driving, so it wouldn't really be sequestering.
See syn-gas to methanol process from the 1920's by Alwin Mittasch and Mathias Pier. Or alternatively the newer processes involving a copper catalyst.
Re:Darn that dirty hydrogen (Score:4, Interesting)
You can melt steel with a 10' mirror. You can't melt *much* steel, but getting high temperatures isn't a problem; the question is whether the yield is enough per square meter of mirror to be worth it, and whether it scales up to higher efficiencies as you increase the area of the mirror and the size of the reactor vessel.
Re:Darn that dirty hydrogen (Score:4, Interesting)
coal is very easy to move around, all you need is a bucket big enough.
Hydrogen is very hard to move around under pressure. as one of the other ./'ers aid like trying to hold water in a strainer.
Even Gasoline is relatively easy to transport.
Re:Darn that dirty hydrogen (Score:5, Interesting)
You're proposing a cycle that goes something like:
solar mirrors -> zinc reactor -> hydrogen furnace -> turbine
Why not just use the old and tried method of:
solar mirrors -> hot steam -> turbine
It would be simpler and far more efficient.
Now, the story is interesting because it's about creating hydrogen using sunlight, without converting the sunlight to electricity first.
Store it as fertilizer etc (Score:5, Interesting)
As a fuel hydrogen gas is a pain to store and transport in comparison to butane, propane etc or a liquid fuel, but if you can make it at sane costs where you need it then you don't need to store or transport much of it.
Re:Darn that dirty hydrogen (Score:5, Interesting)
Re:40 rods to the hogshead (Score:4, Interesting)