Thread: running on hydrogen gas

Tweet

Great to hear about the new cell design, Robot. Also interesting about the membrane Brian!

Here is some interesting reading on the subject of oil:

http://www.gravmag.com/oil.html#dollar

mike in tucson

Since hydrogen can pass though membranes more easily than other gases whose molecules are larger that is also an added problem of leakage from whatever container it is stored in.

Don Shillady
Retired Scientist/teen rodder

I think someone mentioned the hindeberg!

I did a google search, and one site i found claims the us makes about 2billion cubic feet of hydrogen a year, so how many cars could that run?

Not many... about a million hours of driving which is not even one day for the USA cars. Here is an interesting hydrogen article with the source at the end:

"Consider a mid-sized car, traveling at 60 mph down an Interstate Highway. It is well known (and easy to calculate) that roughly 40 actual horsepower is needed to maintain a constant speed. A horsepower is equal to 2544 Btu/hr, so we are talking about 102,000 Btu/hr of "actual" energy/work. For an hour's driving, we would therefore need 102,000 Btu of output energy. (A gasoline engine would use maybe 3 gallons of gasoline during that hour's driving (20 miles/gallon) which actually contained about 378,000 Btu of energy, but the engine/car efficiency is only around 25% to create the 102,000 Btu of output work.) Consider now that a cubic foot of Hydrogen (not compressed) only contains 319 Btu per cubic foot. That hour of driving would therefore require over 1,000 cubic feet of the Hydrogen.

We can say this same thing in terms of "gallons". A gallon of gasoline contains around 6 pounds, and has 126,000 Btus of energy in it. A gallon of hydrogen (gas) only contains around 40 Btus in it. Quite a difference! Instead of a two cubic foot gasoline tank (15 gallons) in your car, you would need a tank more than 3,000 times bigger, over 6,000 cubic feet, for the equivalent Hydrogen! That's a little more than TWO standard semi trailers (8'wide x 8'high x 45' long or 2900 cubic feet each). Pretty big gas tank!

Well, that is obviously not going to happen! So, the many ongoing explorations into using Hydrogen as a fuel always involve carrying HIGHLY COMPRESSED Hydrogen in very thick, heavy tanks. If you have ever seen the kinds of tanks used for the Oxygen for a worker's oxyacetylene cutting torch, that's the kind. Such tanks can hold Hydrogen at around 100 times atmospheric pressure, or 1500 PSI, an extremely high pressure (or even higher) (We will later mention even higher pressure hydrogen tanks at 3000 PSI).

Well, at 100 times atmospheric pressure, the Ideal Gas Law tells us that the Hydrogen would now only take up 2900/100 or 29 cubic feet. That works out to around 60 of those (fairly large) high pressure storage tanks (to match the effective capacity of the 15 gallon gasoline tank.). Each tank is very massive to withstand the very high pressure, and each weighs nearly 100 pounds empty. (And around 1/4 pound more when filled with Hydrogen!) So the normal American car which presently weighs around 2800 pounds would have around an extra 6,000 pounds added, so the vehicle would now weigh more than three times as much as current cars! (This tremendously affects acceleration, handling and other performance, and it would be like that car pulling a huge 6,000 pound trailer behind it." exerpt from http://mb-soft.com/public2/hydrogen.html

So how much hydrogen is in the space shuttle`s tank?

2 million liters of hydrogen and 2 million liters of oxygen, both in liquid form. Remember, the shuttle also has solid fuel boosters too. And, it gets worse mileage than a big block Chevy!

Look, energy is energy. There is no free lunch any way you slice it. The space shuttle uses liquid hydrogen and oxygen. When it hits the nozzles it transitions into vapor. Obviously this is more better than gasoline>

With HHO people always semm to get carried away the total deal. That is, running your engine totally on HHO. This does make sense to me. However I am on the fence wrt using it to suppliment your engine. I have seen some data that indicates it works and some that refutes it.

Don't just think in terms of energy here, think about $/mile ...............

Kitz

Interesting article in the current issue of Design News.
They compare the energy per kilo for gasoline vs. Lead acid vs. lithium ion batteries.

Gasoline has 12,722 W-hr per kg (watt hours per kilogram)
Lithium batteries have 150 W-hr per kg
Lead Acid batteries have 50 W-hr per kg

What this is saying is that, if you want to go as far as one kg of gasoline will take you, you have to have have almost 85 kg of batteries! No wonder electric cars either weigh a bunch OR they get terrible range. Even if you factor in the inefficiency of a gasoline engine, the gasoline is still 25 times the energy density of the good batteries. It's going to be quite a few years before good ole gasoline gets beat for portability, distribution networks, cost, etc.

Aye, there's the rub, as ol' Will S said. Until they come up with an alternate fuel that I can get a pailful of, and carry it home to my yard tractor, or whatever, I guess we're stuck with gasoline. Methanol might be practical, but the manufacturing process is going to need simplifying to bring the costs down. Hydrogen looks good, until you do the math like robot did.

I reread some of the literature from my old connection to a fuel gas company. The real hitch to the whole idea is that Browns gas and HHO contain oxygen mixed in with the hydrogen and that is an explosion waiting to happen. There needs to be some cheap way to separate the O2 from the rest of the gases. That is easy in low voltage electrolysis lab demos but not so easy when carbon containing waste is also used. O2 is magnetic while H2 and CH4 are not so maybe some sort of magnetic trap could separate out the O2 in principle but gases at room temperature are notoriously random so it would take a very strong magnetic field to separate out the O2. The bottom line is there there is no easy way a process can be set up safely with a cheap quart jar device. Overall I still like the idea of a remote nuclear reactor generating electricity with me plugging into an outlet to charge some batteries for a lightweight three wheeled two-passenger vehicle! Some of you younger folks missed out on the Saturday matinee movies that showed the burning Hindenberg over and over and over similar to the TV coverage of the 9-11 airplane crashes in New York. Anybody who saw that Hindenberg fire (over and over) fire will not want to mess with H2!

Don Shillady
Retired Scientist/teen rodder

Well that's something that I wouldn't be going near. If it's just a matter of saving a bit of gas, what about adding acetone to your fuel. Has anyone ever tried this???

http://www.pureenergysystems.com/new...00069_Acetone/

Sean

Actually, Don, it's not hard to keep the two gases separate. With DC current, collect the gases from the Positive wire in one container and from the Negative one in another. One is hydrogen, the other oxygen. There'll be some impurities from tap water not being pure, but very little.

R. Pope, I have done that a number of times and that is what I meant by "low voltage electrolysis". As you say all you have to do is separate the electrodes and allow space above each for the bubbles. However with the higher voltage arc method using carbon-containing waste materials, the electrodes have to be immersed in the waste and so the arc just sprays across the mess and the resulting gases are mixed. I do not choose to say more.

Don Shillady
Retired Scientist/teen rodder