African teenagers invent a urine-powered generator | Hacker News Reader

African teenagers invent a urine-powered generator

makerfaireafrica.com

Hmmm

>The system works like this:

Urine is put into an electrolytic cell, which separates out the hydrogen. The hydrogen goes into a water filter for purification, which then gets pushed into the gas cylinder. The gas cylinder pushes hydrogen into a cylinder of liquid borax, which is used to remove the moisture from the hydrogen gas. This purified hydrogen gas is pushed into the generator.

Don't electrolytic cells need electricity to split water into hydrogen and oxygen? Also why have they got 2 automotive fuel filters on top of that tank of red stuff and why are the filters venting to the atmosphere? Isn't that wasting their precious hydrogen? 6 hours of elecy from each litre of pee? I'm certain that if pushed I could generate about a litre an hour and thus this machine would power my pc , my router and charge my iPad for free.

Or not because this story is bullshit. Seems others think so too http://nathan-lee.com/blog/2012/11/07/urine-powered-generato...

There's a lot of skepticism going on. I too don't see it working either, although I lack the knowledge to judge.

From what I've read so far it certainly does require power and doesn't jumpstart itself. Question is how much power does it need, and how much is it able to generate. Maybe not their simple experiment one, but an industrially optimized one.

Still looks like sth that has already been tried and the math just doesn't work, yet it's remarkable that these young girls are working on these problems. It shows what education can do and impressed me nontheless.

They use an electrolytic cell to extract the hydrogen from the urine...

http://en.wikipedia.org/wiki/Oxyhydrogen#Fringe_science_and_...

> the energy required to split water molecules exceeds the energy recouped by burning it

Maybe they pee onto a turbine to recharge the battery.

Well, except they don't split the water, but the urea contained in the urine. Now, I don't know whether that process takes more or less energy than you gain by burning the end result, but it's not the same process.

You can't electrolyze urea by solving it in water and passing electricity through the solution, for that you'd have to melt pure urea and electrolyze that. Problem is that it will decompose above its melting point.

So, even when urea is solved in the water, only the water is electrolyzed (in hydrogen and oxygen).

Why would you need to melt the urea to electrolyze it? I'm actually a little behind with my chemistry, but you can electrolyze NaCl (salt) when dissolved in water, without melting it. The basic requirement is that the solution contains ions. Now I must admit that I don't know the basic reactions of urea with water, but given that you can use urea as hydrogen source in fuel cells [1] I'd assume that it should work as hydrogen source in an electrolytic process since the basic reaction is somewhat similar.

[1] see https://en.wikipedia.org/wiki/Urea#Laboratory_uses

Edit: There are papers about direct electrolysis of urea

http://www.suttonfruit.com/pics/urea_electrolysis.pdf (I think its a copy of http://pubs.rsc.org/en/Content/ArticleLanding/2009/CC/b90597...)

http://etd.ohiolink.edu/send-pdf.cgi/Singh%20Deepika.pdf?ohi...

Now I don't know how legit they are, but seems ok to me.

http://webcache.googleusercontent.com/search?q=cache:7Tim1l5...

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