Hey....DCF...

[ancona]

This page will detail some very interesting and functional processes utilizing peroxide as a fuel and a source of hydrogen in the production of electricity and as a fuel source for internal combustion. Many of these ideas have been around for a long time, but a few of them are new and as such, quite exciting.

http://www.americanenergyindependence.com/peroxide.aspx

 

[DCFusor]

Interesting...hydrogen peroxide isn't a source of hydrogen, it's a source of oxygen and hot water. Having fooled with some at fairly high concentration, I wouldn't want to be in a car with it, though...it's pretty dangerous stuff and becomes less stable the higher the concentration. Even at 50% (which is a lot lower than the rocket boys use) a single catalytic event (say, drop in a crystal of potassium permanganate, or just hit the tank with a hammer) - boom!

As they point out there - you have to put in all the energy (and more) you're going to get out, so strictly speaking, this isn't an energy source - it's a storage medium.

If you were going to build up an integrated system, you might think about converting natgas to propane, which gives off spare hydrogen (to make the peroxide with or make other fuels) and burn propane with the peroxide (which gives off oxygen when it decomposes). Since natgas is real cheap at the moment, at the plant scale, you might be able to do something cheaper than oil that way.

IIRC, NASA uses peroxide with various fuels in some thrusters, usually small hypergolic ones for things like maintaining orbits. Hypergolic is a fancy word for "it lights itself when the fuel and oxidizer mix in the engine". So it's handy for them, and they get way out there on the fuels used - hydrazines etc, some other nasty stuff if you don't handle it pretty carefully, or borane types of things you really can't use near the planet (all very poisonous). All these things are much more dangerous than gasoline to handle, and require a lot more purity than a current "fuel station" can provide to keep them from "going off" on their own - or killing you by poisoning you if they get away.

The thing is, what makes gasoline/oil rule as a fuel, is that you don't have to carry the oxidizer around with you at all - it's free, in the form of air (but air is only 20% oxygen, so there's a penalty of having to heat that nitrogen mixed with it that otherwise doesn't give you any energy). The upshot is that you don't carry about 15/16ths of what makes your car go, weight wise. Pure oxygen would make a far better oxidizer for an engine, but it's kind of a trick to separate air into O2 and N2 on the fly, and a bear to carry pure O2 without cryogenics. Hence the current compromise in how we usually do all this. Also, pure oxygen would require a lot higher octane in your fuel (in a non-diesel).

This is also what puts electric cars at a relative disadvantage - they're carrying both as well, so my 400lb or so battery pack in the Volt is worth just about a gallon of gas, energy-wise.

What that buys me of course, is that there are a heck of a lotta ways to get to electricity (though none that burn fuels are much more than 40% efficient at present, those pesky laws of thermodynamics - but that's still better than the peak gasoline engine efficiency around 30% - 33% better and that's comparing to the gas engine's peak, which only some hybrids see regularly).

In the case of the sun, the fact that my panels are about 14.5% efficient is not a big deal - the input is free anyway and would have been completely wasted otherwise heating my roof.

 

[ancona]

DC,
I'm currently bidding a bunch of work in the HMF area at KSC. One of the buildings is where nitrogen tetraoxide is manufactured along with hydrazine. Yes, they are both quite nasty but they are outstanding fuels for use in space flight. Working in that area requires an initial safety class to learn how to read the wind socks and where the marshalling areas are, and a second class that explains how the stuff is made, stored, transported and used. All in all, I would say HMF safety qualification classes are right up there with VAB safety and open grain class.

I have used peroxide injection to remediate hydrocarbon contamination via well head injection methods. The result was nearly immediate and quite profound. The entire subsurface heated up radically and there was a palpable "whooomp" as the reaction occurred. Of course, the entire area was rendered completely sterile, but at least teh hydrocarbons were gone.

 

[bushi]

(...)(though none that burn fuels are much more than 40% efficient at present, those pesky laws of thermodynamics - but that's still better than the peak gasoline engine efficiency around 30% - 33% better and that's comparing to the gas engine's peak, which only some hybrids see regularly).

In the case of the sun, the fact that my panels are about 14.5% efficient is not a big deal - the input is free anyway and would have been completely wasted otherwise heating my roof.

yeah, these are all points I was wondering about - it might not look like much difference between 30% and 40% efficiency, but if you look in the relative terms, as gasoline engine being point of reference (our current "prime mover"), than electricity generation is 33% more efficient, from the same fossils (10% difference is 1/3 of our base 30% efficiency). Not to mention, if you use so called Combined Heat & Power plants (CHP), where the waste heat is also used (as technologic process heat, or even for doomestic water usage - on metropolitan scale), the efficiency gets as good as in the region of 70+%. It can be also quite cost effectively supplemented & further improved upon by renewables (initial heating of water in steam turbines by concentrated solar, for example). And as electric transport goes, electric power trains have some more advantages over the ones that must accompany ICE engines (for example, nearly flat torque through the whole 0-max RPMs range, thus no transmission required - another weight & mechanical efficiency gain, no idling, less complex=more reliable & less maintenance)


The other thing you mention, re: photovoltaics - I am always puzzled about the excitement, that this or that laboratory "have achieved better efficiency photovoltaic cells", - at the expense of exotic processes or high costs, or exotic materials. I say: why bother? Increasing efficiency is only important, when we have to save fuel, but here, the "fuel" is free, like you said. IMHO, the focus of development should be on making CHEAP, easy to manufacture, environmentaly friendly and long-lasting cells - even if it comes at the cost of slightly lover efficiency. I mean, if your panels were say 10% efficient, Fusor, but would cost you, say, a quarter of what you've paid - you'd just double the square meter area, comparing to what you have, and we are good, no?

regarding hydrogen peroxide - there are good few go-carts powered by that stuff, to be googled for your amusement. But it is dangerous & unstable stuff indeed, and I would prefer not sitting on the tank full of it as well!

BTW, if my memory serves me well, Russian torpedoes on board of one "Kursk" submarine were powered by H2O2, which was quoted as the most probable cause of explosions & the following tragedy, by independent investigation body (ie non-Russian-government one)

 

[DCFusor]

This link is pretty instructive and jives well with my own experiences in the lab.
http://en.wikipedia.org/wiki/Hydrogen_peroxide

The problem with it in high test is that it can go boom all by itself...and it's deadly, though not as bad as some of the other things NASA plays with. I have some 6% stuff and it burns you faster and nastier than 70% nitric acid...you wear gloves when using even that "weak stuff" which is the strongest you can normally buy as a civilian.
35% is the strongest that can be shipped as a hasmat unless you're the US gov.

My main use in the lab here is to make "piranha solution". That's a mix with sulfuric acid, and that combo will eat anything but glass - even baked on carbon off my glassware just goes poof. The standard before that was mixed sulfuric and chromic acid, which is much nastier as regards human contact (hexavalent chrome is a carcinogen on top of burning and poisoning you), but doesn't really work any better as a cleaning agent. Even weak solutions of piranha solution (like battery acid and hair salon peroxide) are really wicked cleaners, oxidize anything that can be oxidized almost (including you). Now, 98% sulfuric + (only) 6% hydrogen peroxide - that will start most things on fire instantly and toss that nasty stuff back at your face...I'd hate to think what high test peroxide would do in that combo. To even make it, you'd have to have atomically clean containers, as a bit of dust would make it explode when the peroxide was added. Fun stuff! Think "nitroglycerin" in terms of how touchy it is, except the nitro doesn't just go off if you pour it over a bit of dirt.

Edit:
Yes, of course on the PV cells. But I have room and don't care what they weigh. So NASA for example really does care about weight and for them, it's worth it considering how much per pound it costs to get them up there. The rest? Seems pointless as even if they got 100% you're still not solving the problem of dense city dwellers - you'll just never get there for them. And far too much is being wasted on cheapness, frankly. Most of that thin-film or even "paint on" junk is just that - junk. No ability to live out there in the weather and it microcracks in the thermal cycling you get every day - usually they fail in a year or two. Plain old polycrystalline silicon has shown itself to last decades - I have some that old that ar still fine - and most of the cost of a quality PV panel isn't really that - it's the glass, the frame, and the fancy stuff that has the same tempco as the cells so they don't crack on temperature changes. These days, they don't cost more than a quality window at the hardware store per sq foot.

For "old school centralized power" plants, most are going to "solar dynamic" - including NASA. There you just concentrate sun onto a heat exchanger, then do the boiler thing - and in a big plant you get to 40%. No new science or tech required for that, but it isn't economical till things get pretty large.

 

[bushi]

Most of that thin-film or even "paint on" junk is just that - junk. No ability to live out there in the weather and it microcracks in the thermal cycling you get every day - usually they fail in a year or two. Plain old polycrystalline silicon has shown itself to last decades - I have some that old that ar still fine - and most of the cost of a quality PV panel isn't really that - it's the glass, the frame, and the fancy stuff that has the same tempco as the cells so they don't crack on temperature changes. These days, they don't cost more than a quality window at the hardware store per sq foot.

...wow!! Thanks DCF, I just had another "wow" moment thanks to your postings . Indeed, I wouldn't thought about the issues you mentioned (like the different expansion rates of cells vs. glass they are glued to, causing cracks and deterioration).

Like they say, the devil is in the details...

 

[DCFusor]

Google, Walmart, and other less experienced "fast" folk who jumped on the "cheap thin film" solar on the advice of scientists - not engineers - are finding out what matters is total cost of ownership...and it's real high for that initially-cheap stuff.
If it only lasts 1/10th as long...it'd better be cheaper than it is, not even counting the cost of a re-install. It's a blind alley.

Been burned on it myself. Went right back to the good-old tech, and it lives forever, seemingly (some here are over 35 years old and still fine). That's why it's not so cheap. It's not like the world is going to run out of silicon, or the silica for the glass anytime soon...and it's a lot less poisonous than the thin film materials, cadmium, lead, selenium etc etc.

I think most of the "amazing increase in efficiency" press-release-science junk is about things that started out 5% efficient and got 20% better than that (to 6%!), and is driven by a scientist's desire for continued funding...Physorg.com is rampant with "press release science" where the wording carefully avoids making that easy to figure out.

The real issue is how you measure this. As I posted elsewhere here, photons come in all energies. In the photo-electric effect, this relates directly to the cell output voltage. If you set up a cell to see only the higher energies - say blue, then you get higher voltage, but there are fewer blue than red and IR photons - you get nothing from them in that case. If you set the system up for red photons, then there are more of them (more current) but less voltage per cell. The really fancy stuff NASA uses for satellites has more than one layer - say a layer that "eats" blue photons on top of one that eats red ones, which are hooked up separately. The trick is making that eats blue layer transparent to red (possible, but difficult) and putting that whole mess together. To get anywhere near 100% you'd need multiple layers, but that quickly become self-defeating due to losses in the upper layers eating some photons that make no power before they get to a layer that could use them. Worth it when you're paying a fortune per pound to get them into orbit, not for us mere mortals.
I've got a few QA rejects of those, they are cool, but man...price is "out of this world".

Solar is one (and maybe the only) place where the usual "specsmanship" works for us, instead of against those who aren't paying attention. The standard test is space-level solar radiation coming straight in. Due to the polycrystalline silicon, not all the light acceptance is best straight on, so they have to oversize the cells to make the ratings look good on their test rig. Yet, there are plenty of crystals oriented to eat light best from oblique angles. On partly cloudy days, when the light is coming from all directions, they WAY outperform single crystal (which are more expensive) type panels that used to be the standard. And partly cloudy is when you need the extra performance the most - for once, the world is working for ya. Going to poly-crystal was the big leap, many years back...

 

[rblong2us]

Hah shoulda listened to the engineers (-; -

Understanding Engineers #1

Two engineering students were biking across a university campus when one said, "Where did you get such a great bike?" The second engineer replied, "Well, I was walking along yesterday, minding my own business, when a beautiful woman rode up on this bike, threw it to the ground, took off all her clothes and said, "Take what you want." The first engineer nodded approvingly and said, "Good choice: The clothes probably wouldn't have fit you anyway."

Understanding Engineers #2

To the optimist, the glass is half-full. To the pessimist, the glass is half-empty. To the engineer, the glass is twice as big as it needs to be.

Understanding Engineers #3

A priest, a doctor, and an engineer were waiting one morning for a particularly slow group of golfers. The engineer fumed, "What's with those guys? We must have been waiting for fifteen minutes!" The doctor chimed in, "I don't know, but I've never seen such inept golf!" The priest said, "Here comes the greens-keeper. Let's have a word with him." He said, "Hello George, what's wrong with that group ahead of us? They're rather slow, aren't they?" The greens-keeper replied, "Oh, yes. That's a group of blind firemen. They lost their sight saving our clubhouse from a fire last year, so we always let them play for free anytime!." The group fell silent for a moment. The priest said, "That's so sad. I think I will say a special prayer for them tonight." The doctor said, "Good idea. I'm going to contact my ophthalmologist colleague and see if there's anything she can do for them." The engineer said, "Why can't they play at night?"

Understanding Engineers #4

What is the difference between mechanical engineers and civil engineers? Mechanical engineers build weapons systems. Civil engineers build targets.

Understanding Engineers #5

The graduate with a science degree asks, "Why does it work?" The graduate with an engineering degree asks, "How does it work?" The graduate with an accounting degree asks, "How much will it cost?" The graduate with an arts degree asks, "Do you want fries with that?"

Understanding Engineers #6

Normal people believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.


Understanding Engineers #7

An engineer was crossing a road one day, when a frog called out to him and said, "If you kiss me, I'll turn into a beautiful princess." He bent over, picked up the frog, and put it in his pocket. The frog spoke up again and said, "If you kiss me, I'll turn back into a beautiful princess and stay with you for one week." The engineer took the frog out of his pocket, smiled at it and returned it to the pocket. The frog then cried out, "If you kiss me and turn me back into a princess, I'll stay with you for one week and do anything you want." Again, the engineer took the frog out, smiled at it and put it back into his pocket. Finally, the frog asked, "What is the matter? I've told you I'm a beautiful princess and that I'll stay with you for one week and do anything you want. Why won't you kiss me?" The engineer said, "Look, I'm an engineer. I don't have time for a girlfriend, but a talking frog - now that's cool."