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Old 09-11-2012, 17:30   #16
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Re: Taking the Pi$$!!

Delatbabel, you are just a spoilsport... injecting some facts into what was a pleasant fantasy. You must not really understand internet science!

Well done, mate!

Cheers,

Jim
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Old 09-11-2012, 18:03   #17
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Re: Taking the Pi$$!!

Well, the reporter may have been off base on the science involved, but let's not forget these are 14-15 year old girls doing a project for a science fair.

They have a bright future.
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Old 09-11-2012, 18:15   #18
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Re: Taking the Pi$$!!

Quote:
Originally Posted by simonpickard View Post
If you installed a water maker, drank a lot, and used this I wonder if we'd see the worlds first perpetual motion machine?!
Same idea here.

Finally we can go cruising without water tanks. Bring your own beer ;-)

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Old 09-11-2012, 18:34   #19
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Re: Taking the Pi$$!!

It's a fuel cell.
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Old 09-11-2012, 18:42   #20
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Re: Taking the Pi$$!!

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In early welding devices (19th C) it was common to use a mixture of Hydrogen and Oxygen to weld, however storage and use of the combination is highly unsafe. Modern techniques have switched us to acetylene and other gases instead, which produces much the same result but is safer.
I am not sure about the welding bit but it was used for cutting steel underwater--the Navy used it. Hydrogen stores well too--acetylene has to be dissolved under pressure in Acetone or some porous material. Hydrogen can be stored at very high pressures. Unfortunately it forms an explosive mixture with oxygen at fairly low concentrations. Early battery systems produced hydrogen when fully charged--and this gas had to be extracted from large battery banks and storage systems.

You are spot on with the methane energy though--it can provide useful energy and will be used increasingly in the future--but it is a bit bulky at present to go on board, although a flotation gasometer could be replaced by a bl;adder--it may bit be deemed safe enough. During WW2 buses had large bladders on the roofs and were powered by both coal gas and sewer gas--but these were desperate times. "Brown"s Gas was I believe "Water Gas" which is produced by blowing a mixture of steam and air through glowing hot anthracite or coke. The water breaks down to hydrogen, releasing co2, which is then broken down to carbon monoxide with further reduction. So--Water gas was poisonous but a good fuel, but like the dangerous coal gas--costing more in terms of energy to produce than it provided, albeit more conveniently. Water gas was also used in motor vehicles via gas producer equipment fastened to the vehicle or towed behind it--but some dispensed with the water and just ran the vehicle on the scrubbed carbon monoxide--which made the whole thing quite portable but less powerful. Still--third gear travel might be better than no travel at all--On a boat steam power was deemed to be vastly superior until Diesel came along.
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Old 09-11-2012, 19:26   #21
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Re: Taking the Pi$$!!

Just checked up and found "Brown's Gas" as a mixture of hydrogen and oxygen--which seems a tad dangerous to me. Anyway, my previous post which I am unable to amend is incorrect in stating that Water Gas is "Brown's Gas"
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Old 09-11-2012, 19:50   #22
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Re: Taking the Pi$$!!

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Originally Posted by delatbabel View Post
OK, so there appear to be a bunch of confused people, so just to clear up some points:

We must remember that urine has large amounts of ammonia in it.

No, it doesn't. Ammonia is one of the common chemical or bacterial breakdown products of the nitrogenous compounds in urine (and in fact breakdown of many animal and plant products), but natively urine contains no ammonia.

Ammonia is also flammable.

No, it's not. Although there is technically an exothermic reaction when you burn ammonia, the temperature of that reaction (i.e. flame temperature) is lower than the ignition temperature of ammonia. So it doesn't count as flammable because attempting to light it isn't self sustaining.

In the presence of a catalyst such as platinum gauze, it will flame but it doesn't count as flammable by itself.

Now if they were chemically or bacterially breaking down urine and other bodily wastes (hrm, not to put too fine a point on it but urine isn't the best source) into methane gas and igniting that then they'd have something. That's a technique used in many places in the world, including the third world. In fact it's not uncommon to find a sewage treatment plan that runs entirely off the energy it generates from gases it produces from the waste it treats, and furthermore feeds excess energy into the grid.

But that's not what's happening here. What the claim is in the article is that they are electrolysing urine to produce a gas that's fed into a compressor to then feed an engine which powers a generator. The net energy output from that is bound to be negative.

You could power an engine from the methane gas produced by chemical breakdown of urine, but 1L of urine wouldn't produce a significant amount of methane and hence wouldn't power the generator for very long. Typically waste-gas generators run from hundreds or thousands of tonnes of human or animal waste.

Now, most people know electrolysis produces Browns Gas.

Actually, no, most people don't know that, because it's nonsense science. "Brown's Gas" is a pseudo-science name for a mixture of hydrogen and oxygen. Those gases can be produced separately from electrolysis depending on the liquid you're electrolysing, but in general electrolysis doesn't produce anything known as "Browns Gas".

If you see those ads for devices that you fit to your engine that break down fresh water into "HHO" or "new forms of water" or other such nonsense compounds, well really all they do is use electrolysis to break down water into Hydrogen and Oxygen, recombine it and feed it into your engine. The net energy used to break down the water is in theory exactly equal to the net energy released in recombining the two, because of conservation of energy, but in fact in a not-perfect system there will be some energy leakage and in fact it doesn't gain you fuel efficiency but it costs you fuel efficiency (because the extra energy used by your alternator to generate the electricity to electrolyse the water is less than the energy you get back by recombining it in your engine).

It's analogous to the process being described in the article. If you break down water into hydrogen and oxygen, and then recombine it into water (which happens in the engine) then in theory the energy gained is exactly equal to the energy used. In practice the energy gained is less than the energy used because of inefficiencies in the system (show me a 100% efficient light bulb).

In early welding devices (19th C) it was common to use a mixture of Hydrogen and Oxygen to weld, however storage and use of the combination is highly unsafe. Modern techniques have switched us to acetylene and other gases instead, which produces much the same result but is safer.

What is really strange is if you research the operation of the ammonia refrigeration cycle, hydrogen is used in the process for the continuous loop (bonding-return side).

Umm, yeah, but that's a completely different process -- physical (condensation and evaporation of gases) rather than chemical.

So, before you totally discount the system, you may want to give it a break, unless your a PhD in chemistry.

Not a PhD but I do have a science degree.
For someone with a science degree you sure use Wikipedia a lot.

Humans expel about 50 mg of ammonia per day. That is much more than none.

So ammonia burns. That is flammable, as it is listed in MSDS, even though it's not self sustaining.

Although Brown's Gas is a fringe scientific term, it is a ratio of 2 to 1 which electrolysis produces. In a dangerous manner, just for information, if not separated with a Hoffman electrolysis type device.

What effect might the hydrogen have on the ammonia? You state it's a physical reaction, but don't say what effect that may have in the action of things.

Funny, you copied a lot of information, but didn't say anything.

So why did you post a bunch of copied Wikipedia information?

James L
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Old 09-11-2012, 22:18   #23
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Re: Taking the Pi$$!!

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Originally Posted by propellanttech View Post
For someone with a science degree you sure use Wikipedia a lot.

Humans expel about 50 mg of ammonia per day. That is much more than none.

So ammonia burns. That is flammable, as it is listed in MSDS, even though it's not self sustaining.

Although Brown's Gas is a fringe scientific term, it is a ratio of 2 to 1 which electrolysis produces. In a dangerous manner, just for information, if not separated with a Hoffman electrolysis type device.

What effect might the hydrogen have on the ammonia? You state it's a physical reaction, but don't say what effect that may have in the action of things.

Funny, you copied a lot of information, but didn't say anything.

So why did you post a bunch of copied Wikipedia information?

James L
The fact remains that you can't electrolyse water into hydrogen and then recombine the hydrogen with oxygen (whether you use atmospheric oxygen like an engine would, or keep the two combined as "Browns Gas"), and gain energy out of it.

In answer to the rest of it:

* You can't burn ammonia in a self-sustaining reaction without a catalyst.

* You can't run an engine for 6 hours on 50mg of ammonia.

* Hydrogen and ammonia don't react (at normal room temperature, without any other reagents or catalysts).

* You can't combine hydrogen and ammonia and get a compound that has more chemical energy than the sum of the chemical energy of the hydrogen and the ammonia separately. If you burn it (or use it in a generator) you won't get more energy than just using the two separately.

I'm sure that basic information and the chemistry behind all of that is on wikipedia somewhere but it's also simple high school chemistry.

I do read wikipedia but I also write for it.
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Old 10-11-2012, 10:59   #24
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Re: Taking the Pi$$!!

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Originally Posted by delatbabel View Post
The fact remains that you can't electrolyse water into hydrogen and then recombine the hydrogen with oxygen (whether you use atmospheric oxygen like an engine would, or keep the two combined as "Browns Gas"), and gain energy out of it.

In answer to the rest of it:

* You can't burn ammonia in a self-sustaining reaction without a catalyst.

* You can't run an engine for 6 hours on 50mg of ammonia.

* Hydrogen and ammonia don't react (at normal room temperature, without any other reagents or catalysts).

* You can't combine hydrogen and ammonia and get a compound that has more chemical energy than the sum of the chemical energy of the hydrogen and the ammonia separately. If you burn it (or use it in a generator) you won't get more energy than just using the two separately.

I'm sure that basic information and the chemistry behind all of that is on wikipedia somewhere but it's also simple high school chemistry.

I do read wikipedia but I also write for it.
And who exactly said you would get more energy than the two separately.

Funny, anyone can write for wikipedia.....so I'm not impressed.

I love people who take something scientific, and tear it apart, but never try it.

You didn't do anything but reiterate everything twice. You didn't do anything but draw out the thread with no additional information.

You are wasting bandwidth.

James L
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