Instructables

Hydrogen as a fuel?

It's easy to separate hydrogen and oxygen from water. If you mix them together it doesn't become water until it is burnt. In theory you could make a water rocket from gases. But in reality...

conntaxman6 years ago
Everone says to make HO is not cost eff.can any one figure out this for me. If oil for you furnace cost $3.75 a gallon , how much will HO. cost to make to the same amount of heat.Useing the will say a 9 plate sys.with dc voltage. tks Johnny also isnt it a better to build a HO gen and Just use the HO and not combine the two.Like for use in a car engine.
PKM conntaxman6 years ago
If you are just burning the hydrogen and oxygen to provide heat, you can save yourself the complexity and get an electric heater. Electric heaters are the only devices that are effectively 100% efficient, so it is physically impossible to improve on their performance using electricity. Also consider that burning hydrogen and oxygen will either make your air very humid, or waste heat in exhaust gas, neither of which happen with electric heaters.
CyborgGold PKM3 years ago
http://en.wikipedia.org/wiki/Electric_heating

look at the section titled environmental and efficiency aspects. If you had the means to produce/obtain HHO, Hydrogen gas, etc. off grid by means of solar or wind feeding the electricity into a generator, or if you collect it through the newly discovered biomass generation methods in the following link:

http://afp.google.com/article/ALeqM5iXbROJgdF3_6BtG3TZFEs9hiw8Cg

then it would indeed be more efficient, though more complex, than using an electric heater (which is overall only about 40% efficient when you consider the losses from a non-nuclear power plant). Add to this the fact that it is a clean energy source, and safe if produced in an on demand system, not stored.

The question about whether or not to use Hydrogen in some form is valid and merits consideration, there are uses for Hydrogen, we just need to get better at producing usable amounts of it. After all, Hydrogen is the most abundant element on Earth, and in the known Universe.
skunkbait6 years ago
Be CAREFUL I made a "hydrogen generator" for my car. It 'electrolizes' (?) hydrogen and oxygen from water, producing "Brown's Gas'. It really helps my mileage, BUT- I forgot and left the generator on for 2 hours and when I went to start the car it went off like a bomb! My family thought I was dead. It shattered my airflow sensor and a good portion of the intake. At least I know it works!
The same thing happened to me... Somewhat. I recently got about 10 jugs of apple juice. (Yumm good stuff, thanks Whitehouse since 1908!) and I built a device, hydrogen generator, I left it on, and when I came back to it, it was expanded so much that I thought it was going to explode. So I picked it up and *ACCIDENTALLY* dropped it......... it exploded and took a portion of my shoe off, and half of the desk that it was sitting on, and knocked the clock off the wall, shattered the food bowl next to it, and *EVEN* dented my computer case.. amazing how much damage one little electrolyzer can do within a 50 foot radius..
oh geee be careful. please hook up the power to the ignition switch so that you have control of the generator by shuting it off. I would like to have a step by step of your generator. thanks
John
Brown's gas

Puts heads in hands...
Yeah, I was wondering there. I occasionally create brown gas, but that is never intentional :-)
. It should contain plenty of Hydrogen (CH4 , H2S, &c). heehee
well, a little methane, but mostly CO2 unless I lose control (which is where the color comes from....I know, Iknow, TMI :-)
You guys sound like my 12 year old! But that's ok, he's a funny kid. BTW, When the intake exploded I nearly made some brown of my own!
Hmm, yeah it sounds like it would be good practice to have its on/off switch "keyed" through the ignition switch so it is turned off when the car is. And luckily you didn't create any "red" with that either.
Goodhart, Nacho - "Brown's gas" is supposed to be a special mixture of H2 and O2 produced by electrolysing water in a special way.

It's more overunity woowoo, but the BG proponents have convinced themselves that they're right.
Yeah, the "brown gas" I was referring to was a bit more risque` ( making reference to the "wet fart" as it were.....I was being a bit childish...but as one get older, it is kind of expected :-)
Oh, I got that, I just couldn't tell if you were ridiculing Brown's gas, or just being a bit literal.
Just to let you know, I'm not a specifically proponent of Brown'ns gas. I just looked up the term after seeing it on one of the sites. All I can say regarding the product of electrolizing water, is that when ignited the results can be spectacular. I understand how to separate the H from the O, and may consider going that route at some point, but the improvements in mileage with my current simple set-up are sufficient for now. Also, just want to let you know, I never paid money to one of the sites selling plans. I don't sell plans. I'd be happy to share my procedures and results with anyone who is interested.
Try this link. Never mind the title, Brown's gas is on page three.
Kiteman Kiteman6 years ago
And this thread is useful.
Thanks. Both were useful. I will abandon the thought of welding with this stuff, and probably try to separate H from O for experimenting with my gas mileage. I can't deny my currently improved mileage, but Yull Brown sounds like a quack!
. The only thing "special" about Brown's gas BrownsGas.com is that the products of electrolysis (H2 & O2 ) are immediately mixed in a common manifold. The term itself does not imply any special properties, especially not free energy. Any special properties have been made up by the HHO (perpetual motion flavor) crowd misusing the term.
In reality they use liquid H and liquid O for NASA's rockets. I mean, technically, water vapor comes out of the business end of the rocket.
eyebot1175 years ago
Don't they sell a toy rocket that plugs into a base, you fill the base with water, turn it on, wait an hour, and then press the button?
Yeah, the estes hydrogen rocket. I used to have one.. It never got taken out of the box, I was to afrad to break it haha
Masterdude5 years ago
The Space Shuttle uses liquid hydrogen and oxygen as fuel.
Kiteman6 years ago
You can power home-made rockets on gaseous hydrogen, without compressing or chilling it like NASA do. I'm sure I've seen an 'ible on it... ...searches... Oh, no there isn't! Basically - set up an electrolysis cell, but deliver both gases, via under-water collection, to a pop bottle. When it's full, put a cork in it. The cork should have two wires through it, with a gap between them, inside the rocket. Apply high voltage to the wires, you're get a spark inside the bottle that will light the gases, firing the rocket off.
What would be the boiling point of hydrogen, I may have a need for it, either that or acetylene, which may be more expensive or cheaper.
According to Wikipedia:

Hydrogen: 20.28 K (252.87 C, 423.17 F)
Acetylene: -84 C
. C and F are negative for Hydrogen. ;)
Doh - of course. Copy-and-paste error...
1) that would not be very practical. 1KV jumps about 1.1 mm. i said sparks. you can stretch an arc out by hand if you want to though. 2) you overlooked something kiteman: as the spark is produced, the 02 in the bottle becomes 03, and the expanding plasma adds trust to the motor.
Why is it not practical? You could use the sparker from a cigarette lighter, like I did for my Party Popper Instructable.
opps. your right. i was thinking about regular high voltage sparks, not piezo ignitors
nick one from a camp stove, they're normal ones but with a nice heavy duty cable and a proper point for better spark jumping...
Patrik Kiteman6 years ago
Except that you'd be creating a *bomb*, not a rocket. A mixture of H2 and O2 is highly explosive, so the whole bottle would blow up at once.

If you want to make this into a rocket, you'd have to keep the H2 and O2 separate, so you can mix and burn them in a highly controlled fashion. That's why that big orange space shuttle external tank is actually *two* tanks: a liquid oxygen (LOX) and a liquid hydrogen (LH2) tank:

Sts_et_cutaway.jpg
Princess_Mellow (author) 6 years ago
Ok. I get the idea. Rocket is expensive and will go bang... loudly.
westfw6 years ago
But in reality:

1) electrolysis is "expensive", energy wise, and nearly all commercially produced hydrogen is made using fossil fuels (usually coal or natural gas. Meaning that the "carbon footprint" of most hydrogen is significant.)
2) If hydrogen and oxygen are pre-mixed, the mixture is quite explosive.
3) hydrogen is awkwardly non-dense, even when liquified. While hydrogen has a very nice energy density per unit mass, the energy density per unit volume is icky.
4) The hydrogen molecule is very small, so that compressed or liquified hydrogen tends to leak THROUGH most containers, including metal tanks.

Estes sells an H2+O2 rocket that electrolyzes water and then ignites the mix.
Certainly burning fossil fuels to generate power to liberate Hydrogen is going to be horribly inefficient not only because you get less energy out of the Hydrogen than you put in splitting it, but also because of inefficiencies in the power generation process from fossil fuels (chemical>heat>kinetic>electrical energy conversion, with losses at each stage).
Fossil fuels are generally portable, so it's easier and more efficient just to carry them in your gas tank.

But Hydrogen might be a workable means of making non-portable power sources portable - for example renewables such as wind, solar, tidal, or other non-portable sources such as nuclear or geothermal.

but as you point out, there are some quite important engineering difficulties with the idea.
Actually, the usual mechanism to generate hydrogen from fossil fuels involve stripping out the carbon with water: (CH2)n + H2O --> CO2 + H2, using an appropriately "friendly" chemical engineering setup (exotic catalysts, heat from burning some of the hydrocarbon with air, etc. A very clever setup, assuming you have hydrocarbons to start with. Since assorted coals and biomass can be converted relatively easily to hydrocarbons, it's pretty flexible. I believe it takes quite a bit less energy than electrolyzing water (cause you ARE oxidizing the carbon which yields some energy "internally"), but I'm having trouble finding reasonable-looking unit-comparable figures on the net...
ry25920 westfw6 years ago
That is called catalytic cracking of hydro-carbons. And there are a few problems. 1.) Catalyst, what do you think it is? Platinum. 2.) It runs at 300 degrees celcius 3.) It vents more co2 than you would if you just burned the fuel 4.) What you have built is an electric car with a tail pipe. 5.) And it would make the cost of transportation fenominal. Listen to the MIT podcast "Fuel Cells and Portable Power Sources" You can find it on Itunes.
westfw ry259206 years ago
Platinum and 300C aren't a big problem; there are lots of other industrial processes in the same range. CO2 emissions at a hydrogen plant MIGHT be better (more easily "scrubbed") than a million individual mobile Hydrocarbon engines. And it's hard to evaluate costs until after you've seen what sort of economies of scale you can get.

But yeah, hydrogen fuel cells are currently pretty far from "green" when you consider the overall fuel supply chain.

Thanks - that's very informative - and it sounds like it's a lot more efficient that way than I had been imagining. Also sounds like it could be good for CO2 capture.
ry259206 years ago
Hydrogen is easy to get, but it is very inefficient to produce. Once you have it, you bleed it across a proton exchange membrane (PEM) , and it produces electricity. Problem, fuel cells need a boast, a catalyst. I'm going to explain this in the way Don Sadoway explained it. "Mother Nature is a woman, and where does a woman shop for a catalyst? She goes to the jewelry store. And guess what the catalyst is? It's platinum. You need platinum electrodes to drive that reaction." Quick and easy, you need energy to make hydrogen and why don't you take all that energy your wasting and put it in a battery? Hydrogen, cost, cost , cost.
Princess_Mellow (author) 6 years ago
But it could still work. THE END! Or is it...
NachoMahma6 years ago
. For the reasons westfw points out, it's just too dangerous for the average DIYer. In his item 2, I'd use very (or maybe even extremely) in place of quite. . I shudder when I think of an eight year old Hydrogen powered vehicle ... sitting in someone's garage ... eight year old seals and hose starting to leak ...
ermmm I just had a similar idea, however does it take much energy to split them? also I just realised how silly I was being I just thought of a perpetual motion machine without meaning to...
it takes more energy to split and compress the hydrogen then you get back by burning it
I realised this myself by the end of my comment, I had some notion of conversion on the fly while burning in a jet that powers the conversion, then realising I would be getting energy for nothing that it wouldn't work, ever...
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