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Ok, so there's all this talk today about a hydrogen infrastructure as an alternative to fossil fuels. The major problem with this is that you need to separate the hydrogen from water, as there are no natural reserves of hydrogen. When you use electrolysis to separate the hydrogen, you're using energy.
And in terms of efficiency, it is far more efficient to use electricity to run, say, an electric motor in a car than to use it to separate hydrogen and then use that hydrogen in a fuel cell.
So theoretically, the ideal solution would be to find a naturally occuring compound that contains hydrogen molecules with bonds that can easily be broken. Ammonia is NH3 (3 hydrogen molecules per every nitrogen molecule) and nitrogen bonds are usually very easily broken. This makes it a very good potential fuel, and in fact in 1981 a man converted a Chevy Impala to run on Ammonia. The only thing is that currently ammonia is usually synthesized from hydrogen, adding yet another level of inefficiency.
One thing that a lot of people don't know is that many types of fish excrete nearly pure ammonia as a waste product. Because of this, I propose an Ammonia infrastructure. And instead of creating Ammonia from hydrogen, the Ammonia would come from massive aquariums with a great number of Ammonia-excreting fish. The water from the aquariums would be constantly filtered and the ammonia boiled out before it got to levels dangerous to the fish. Of course this would take a non-trivial amount of energy to boil the ammonia out, but at least unlike separating hydrogen through electrolysis, the energy needed would be far less than the energy yielded.
Ammonia Powered Car
http://www.youtube....watch?v=L0hBAz6MxC4
Youtube Video [acurafan07, Jan 31 2009]
Fish food
Delta_20Water_20Floating_20Farm
High volume, High protein idea [MercuryNotMars, Feb 03 2009]
Ammonia produces....
http://en.wikipedia.../Ammonia#Combustion
energy when it combusts. [FlyingToaster, Feb 04 2009]
[link]
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The main commercial process to produce ammonia takes CH4 (NG) and puts it through quite a few chemical acrobatics starting with stripping the Nitrogen out. Are there any large-scale advantages to using ammonia as opposed to plain old Natural Gas. ? |
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[Are there any large-scale advantages to using ammonia as opposed to plain old Natural Gas. ?] |
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Eh, mainly the fact that Ammonia has no Carbon and therefore no CO2 emissions. I personally question this whole greenhouse gas emissions thing, but hey it would sure score points with all the greenies. |
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I guess the thing that I like most about this idea is that there is a usable fuel we have available that emits nothing but H2O and N when burned, and is simply peed out by numerous fish. |
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/peed out/
those fish generate ammonia from protein that they break
down, which they have first eaten, which was grown
somewhere, probably with added ammonia. |
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If you are going to recapture ammonia from waste why not
use human waste or feedlot waste? There is already loads of
nitrogenous wastes from big animals. It would not be hard to
make it into ammonia. |
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We make ammonia from stale urine. Just stand a bucket of urine somewhere for a few weeks and the urea will break down into ammonia. The solution is quite volatile and could be distilled easily, even using ammonia itself as the refrigerant. There's also saltpetre, which seems to pack one heck of a punch, and forms naturally from birdlime. The Haber Process is a sledgehammer to crack a nut. Just collect urine publically, leave it and distill it, and do the same with birdlime. The average output of urea per day is thirty grammes. That could yield up to seventeen grammes of ammonia per person per day. I suppose after that you'd get into energy density, specific impulse or whatever, but that's how it breaks down (in two senses). Ammonia is also slightly lighter than air, so you could make an ammonia-powered airship fuelled by ammonia. |
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Maybe with ammonia as a fuel, our fuel can be a byproduct of the cattle industry, rather than the other way around. |
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Biochemistry seems to point to nitrogen fixing bacteria as the obvious mechanism for the bulk, non petroleum method of producing ammonia and ammonium. Not sure as to the exact HC implications but since this reaction requires ATP I suspect it has a CO2 footprint just as large calorie/calorie as burning gasoline, although more efficient than using any larger creature. Keeping it inside the carbon cycle doesn't mean that it won't change the carbon balance. |
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The UK could potentially produce a thousand tons of ammonia every day from its human population. It apparently has half as much energy available as petrol, so that's equivalent to nearly nine thousand barrels of oil a day. We currently use two hundred thousand times as much as that. I find it hard to believe that even including livestock there would be enough ammonia, but i might be wrong. |
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Leaving that aside though, if there's thymol in the urine it doesn't work, so bacteria in urine do at least speed it up, but is there spontaneous conversion from urea to ammonia? There's also a lot of saltpetre and uric acid around. If you left it to happen on its own, uric acid and urea would have to give up carbon and oxygen in some form, though maybe something else could be done with them. However, that carbon is already in the biosphere. It isn't going to add anything. Saltpetre, on the other hand, contains no carbon. |
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This would completely defeat the object, but could an engine be powered by gunpowder? |
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The Mythbusters tried that; they tested a few designs of engine and couldn't get them to work. |
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Couldn't it just be stuck in a rocket? It's the original rocket fuel, isn't it? |
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[nineteenthly], very good thinking about the urine! |
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As to gunpowder, I don't think it would work for any conventional reciprocating engine, but given its nature I'm sure it would be possible to power some form of gas-turbine from it. |
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Not sure about a whole infrastructure, but the idea of an ammonia-burning engine on the local level could be pretty sweet. NH4 is a toxic byproduct of sewage / feedlot operations and if could be captured and burned to run a motor it could provide air conditioning for the pigs. |
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I think industrial ammonia is all synthesized, suggesting that even for ag applications where purity is not essential, it is cheaper to synthesize NH4 than distill it from waste. But if you have to pay to dispose of the waste anyway (eg hog farm) you recapture that savings. Plus you could make a zero-emission tractor as a publicity stunt. |
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In methane-generating manure bioreactor operations I am not sure what happens to the ammonia. My guess is that it needs to be bound up by zeolite to avoid killing the methanogens, and the zeolite is later put on fields or in landfills. |
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Thanks, [acurafan07]. Something i'm currently quite excited about is the realisation that ammonia can be used in a fuel cell. Would that make any difference to the efficiency? It would at least be more versatile than an engine. |
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Iif the mainstream process to make it involves the step "make hydrogen" then at that point you're pretty well done and only have to worry about transportation/storage. |
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Fish excrete ammonia through their gills; it's not "peed out". Because of this, it is excreted in a fairly pure form (along with carbon dioxide). Perhaps you need a fish farm with membranous partitions, the fish being lodged in holes in said partition, thus producing separate ammonia-rich and faeces-rich circulations. The ammonia and carbon dioxide would be constantly removed, and oxygen added. The faeces would be flushed out with fresh water, and used as fertiliser. This flushing rate could be rather slow, as the toxic effects at that end of the fish would be less severe. |
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[nineteenthly], I doubt it would. I just like the idea because in my mind instead of using all the electricity from windmills and solar power etc. to produce hydrogen for cars in the future (hence losing efficiency), it can be used to directly power houses, with the hydrogen coming from renewable Ammonia. |
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And [spidermother], thanks for the correction and that does sound like a better way of doing it. |
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///peed out/ those fish generate ammonia from protein that they break down, which they have first eaten, which was grown somewhere, probably with added ammonia.// |
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I have your protein right here. in the Delta Water Floating Farm idea I just posted. I am using duckweed, more protein than soybeens and I am approaching the scale you need. |
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It is hard for me to find joules input / output for given reactions using google. For example, how many joules is produced by oxidation of NH4 vs oxidation of CH4? I would think there would be a central place to look that stuff up, but I cant find it. |
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I don't see fish farms producing enough ammonia to be "infrastructure" worthy, but if you can figure out how to take the carbon safely out of the current industrial method of production, sign me up [+] |
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I think you'll find that when you try to burn (oxydize) ammonia, you invariably produce lots of Nitric oxide (NO), Nitrous oxide (N2O = "laughing gas"), and Nitrogen dioxide (NO2). These are nasty chemicals that are toxic and greenhouse gasses in themselves. It's probably better just to use methane and produce good 'ol CO2. And BTW, there's no shortage of animals who fart methane (including us). |
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I think they can be broken down with a catalytic convertor, and i seem to remember that nitrous oxide in particular is actually quite difficult to make. Also, i think it turns into water and nitrogen. |
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