Fuel of the Future?
 

Came across this on the web http://hytechapps.com/aquygen Very interesting and the guy has already made an internal combustion engine run on it.

PP

Yes, the water powered car again. The unit claims to produce Hydrogen & Oxygen by the electrolysis of water, which then get burnt in a torch. You only get the flammable gas out of the water if you pump energy into it*, and you get out less energy than you put in. If you produce vast quantities of a mixture of Hydrogen & Oxygen gas and store it somewhere around the house for your next trip to the office the effects of a static spark or a passing smoker could be interesting...

Makes sense in this application though, coz it is burnt as it is produced. The claim: "An Aquygen™ flame in open air burns at only 259° F, but applied to a substrate it can produce temperatures of over 10,000° F" seems incredibly dodgy. On its own it isn't hot enuf to cook a pie, but if you apply it to a bucket of petrol maybe it is more interesting. I thort it burnt hotter than that though, the met guys seem to take it's hazards fairly seriously.

*From wikipedia

Yeah, I'm no scientist, but I thought the demo looked too good to be true. So what is the guy burning with it, or using to extract the energy?

PP

The thing to remember is that hydrogen is not a natural fuel like coal or oil or natural gas. You create hydrogen by using some other energy source to break down water or another hydrogen compound.

Thus hydrogen should be regarded only as an energy storage medium.

Hydrogen Storage
 

Another problem with the hydrogen idea is that the tanks are a b**ger to get right, particularly if you're thinking of trying to use them over say the life of an airliner, and make something light enough to build into an aircraft structure. You run up against all sorts of problems with hydrogen being adsorbed into the metal matrix an making it a lot more brittle over time. Plus anyone remember the DC-X SSTO demonstrator? I may stand to be corrected, but IIRC one of the major problems that killed that beastie was trying to build a composite fuel tank that would hold hydrogen, even at cryogenic temperatures.

Personally I steer clear of all people that a) claim to have discovered some thing new to science AND b) state that "We accept cash, check, and wire transfer" on their web site. One or the other is just fine by me, but not both.

Being to some extent involved in the research business, I allow myself to be fairly open to apparently crank inventors. When I started doing this I predicted a ratio of 9 cranks to one good idea.


To my surprise, I was wrong. I'm currently running at better than 1:1 - although I should admit that the last inventor I had a meeting with, I suggested in frustration he join the flat earth society. I'm not as patient as I was in my youth!

G

True enough, but...

- it is possible to move your hydrogen production to a ground installation where the use of hydrocarbon (or other) fuels can be made as clean as you possibly can. Then, if you (hypothetically) burn hydrogen in an aircraft, all you are producing should be water vapour - which should be harmless to the environment. This offers a huge, although still largely theoretical, benefit compared to our current habit of burning hydrocarbons in the lower stratosphere.

G

Forget it.

Even if we find a cheap, low energy, clean way of producing it, there are still big problems.

Hydrogen is 2700 times less energy dense than gasoline (by volume)! This means to bring it with you
in a car and get further than around the corner, you need to either.
- compress it bigtime
- cool it bigtime (liquify it)

To get the Hydrogen volume down to 3 times the volume of gasoline, you need to compress it
to 800 BARS!! To do that, you need a steel tank that weighs more than your car!!
Also, if you crash or somehow get a gas leak with this, I don't wan't to be in the same part of town.

Cooling it down is very energy consuming. Minimum 30% loss just there. Also, the tank itself needs
a very special design. Double with vaccum in between.
Also you will loose 5% energy each DAY by just having it in the tank. Not acceptable
unless you drive ALOT.

So, I doubt Hydogen will be the solution for a long time.. and probably not in airplanes.

M

That is, 3% range cut in an 16 h sector? Or what? I don´t think hydrogen is just vented, rather it would go to engines and drive the still-liquid part along.

Also, increasing airplane size does leave you with low loading density. Perfect for hydrogen instead of petrol.

Those are escape losses you will get during storing.
Calculating on the aircraft itself only is meaningless since you need to get the
hydrogen from production to the airport, store it there, then load it.

"Delivery of both compressed and liquefied hydrogen would be troublesome. If by road, it would require 13% more tankers so about 1 in 7 lorry accidents would,on average, involve a tanker. If using pipelines, it would take 1.5 times more energy to transfer hydrogen 3,000 km then is contained in the gas itself."

M

So who needs to lug energy around in tanks
 

The nearest to an alternative fuel thus tested is soya oil, blended as an ester with kerosene, which has been demonstrated on a Dart turboprop.

The problem is fuel certification for low temperatures. In this case Soya starts to gel before -40C which I believe is the FAA minimum temp requirement.