I recently ran an experiment by which I mixed sodium chloride, (table salt) with water and used a 9 volt battery and two spoons to perform electrolysis. The result was visible almost immediately. It separated into hydrogen and chlorine gas, leaving a mixture of water and lye (sodium hydroxide).
Chlorine, Hydrogen, and Lye are all useful industrial chemicals, and seeing as how the creation of hydrogen is much faster with salt or seawater than using electrolysis of distilled water, why then are hydrogen proponents using the latter method?
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Hydrogen Production
Tue, 2016-04-05 16:14
#1
ringringlingling
Hydrogen Production
Sat, 2016-04-09 13:57
#2
SquireNed
Well, if I had to guess, part
Well, if I had to guess, part of it is about the mess of chlorine and lye. They're useful for industrial purposes, but if you don't need them or have a way to deal with them they're kinda problematic (what with the whole caustic thing). Hydrogen and oxygen, on the other hand, are actually something that you want to have in your atmosphere (up to a limit); there's no need to worry about toxic byproducts.
Sat, 2016-04-09 14:35
#3
Lazarus
To expand
Just to expand a little bit on what SquireNed said, yes, chlorine and lye are useful industrial chemicals but there is still only so much need for those chemicals. With the large amount of hydrogen that will eventually need to be produced the demand for chlorine and lye would most likely be rapidly exceeded. Figure how many gallons of gas you use in a year, work out how much hydrogen would be required to produce the same amount of energy. Then figure out how much chlorine gas and lye would be produced in producing all that hydrogen. Now compare that to how much chlorine and lye you consume indirectly throughout the year. You will find that you are producing many times what you use.
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My artificially intelligent spaceship is psychic. Your argument it invalid.
Sat, 2016-04-09 20:41
#4
ringringlingling
Chlorine Industrial Applications
We produce 56 million tonnes of chlorine every year. Anything in excess of that could be treated as any other industrial pollutant, and since chlorine is a free radical and reacts easily with other substances, it shouldn't be that difficult to get rid of.
Likewise, we consume 50 million tonnes of lye every year, and like most other bases, it will react with many kinds of acid to produce salt.
According to google, fuel cell cars get 70 miles/kg of hydrogen. the average driver logs in 13,476 miles a year. So you figure 14k miles at 70 miles/kg, thats 200 kg of hydrogen per driver.
Now, in the US, there were 210 million drivers in 2010, multiplied by 200 kg, is 42 billion kg of hydrogen. A metric ton is 1000 kg, so that would only be 42 million tons of hydrogen.
The formulae is 2NaCl (2 molecules of salt) + 2H2O(2 molecules of water)-> Cl2(1 molecule of chlorine gas)+ 2H2(2 molecules of Hydrogen)+2NaOH(2 molecules of Sodium Hydroxide, a form of lye)
So basically, for every 2 parts hydrogen, you get 1 part chlorine and 2 parts lye. you multiply this by their molar mass, and you have approximately 2 gram per part hydrogen, 70 grams per part chlorine, and 40 grams per part lye. So that is 4:70:80, or 2:35:80
this means for 40 million tonnes of hydrogen, you get 700 million tons of lye and 800 million tones of chlorine.
So I guess you really do make a valid point, as that is a lot of industrial byproduct to get rid of, but still, it is technically possible. On the plus side, all this requires is electricity and salt water.
Sat, 2016-04-09 21:25
#5
ringringlingling
Another Problem
It is difficult to find the exact rate at which electrolysis produces hydrogen, especially when using a catalyst, as this data isn't often provided, or is hidden behind techno-babble. I often find when a scientist has something they don't want you to hear, they will resort to using needlessly complex language to describe something.
I do know that electrolysis from distilled water without a catalyst is painfully slow, but saltwater electrolysis is much faster.
Mon, 2016-04-11 10:28
#6
ORCACommander
The reason why pure water
The reason why pure water electrolysis is so slow is that water is too good at being an insulator and thus you require greater voltage. You do not necessarily need Sodium chloride. Any ionically bonded molecule that will increase the electrical conductivity of the solution would suffice
Mon, 2016-04-11 19:34
#7
ringringlingling
That may be true
But what kind of other electrolyte or other conductor could be used that would remain non-reactive during the electrolysis process?
Mon, 2016-04-11 20:33
#8
ringringlingling
Hmm...
you could use sodium hydroxide (lye) and ammonium nitrate (fertilizer) to produce sodium nitrate (saltpeter, also fertilizer) and ammonium hydroxide, which then becomes ammonia and water.
Oh no, wait, thats no good, then you are just using the hydrogen to make nitric acid... you might as well mix the nitric acid with the sodium hydroxide and make sodium nitrate that way... though that might allow you to recycle the ammonia
man, this stuff is confusing...
Mon, 2016-04-11 21:19
#9
ringringlingling
The Real Problem
Isn't finding chemicals to treat the pollution, its finding chemicals that occur frequently enough in nature or other waste processes to make it cost effective to do so.
Tue, 2016-04-12 01:28
#10
R.O.S.S.-128
Money, of course
Actually the main reason water electrolysis hasn't really taken off on an industrial scale is that steam reforming natural gas is significantly cheaper. Partly because the hydrogen-oxygen bond in water is much stronger than the hydrogen-carbon bond in natural gas, and thus harder to break. As I suppose you might be able to infer from the fact that steam has enough energy to break said hydrogen-carbon bond while its own hydrogen-oxygen bond remains intact. Steam is cheap, natural gas is cheap, and as long as both of those remain true then steam reformation remains hard to beat.
Though if you happen to have a method of power generation that produces a hilariously large amount of waste heat as a side effect (for example concentrating solar, fission, or fusion), a thermochemical cycle might be able to take advantage of that, though those are only about 50% efficient right now.
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End of line.
Tue, 2016-04-12 16:35
#11
Trappedinwikipedia
Bingo ROSS, producing
Bingo ROSS, producing hydrogen from natural gas is just more economic. Water is a really stable molecule, so breaking it up is a lot of work.
Mon, 2016-04-18 00:39
#12
ringringlingling
No Shit
C'mon guy, don't be thick. Thats like trying to start a fire and saying, "We'll if I only had my lighter!"
You don't have your lighter, cause there is no more butane. There is no more butane because there is no more oil or natural gas. What you do have is a pair of glasses and the sun.
There is no point in producing hydrogen from natural gas, because you can just burn the fucking gas. This isn't an Al Gore rally, its fucking Peak Oil.
Mon, 2016-04-18 12:00
#13
R.O.S.S.-128
An answer you don't like is still an answer
You were asking why we don't use catalysed hydrolysis. I told you why: we currently have a cheaper way to make hydrogen, and as the cheapest option it predictably is responsible for the vast majority of hydrogen produced.
We have researched a wide variety of hydrogen production methods (for example, you can produce hydrogen by dropping zinc in a reasonably strong acid, but neither the zinc nor the acid are as cheap as gas and steam). However, none of them are likely to go mainstream until they can beat steam reformation, either through a breakthrough that makes it cheaper, or due to natural gas ceasing to be affordable.
In the latter case we will still be able to produce hydrogen, but it will be more expensive because we are forced to use a more expensive method. If you want to chemically boost hydrolysis though, my bet would be on using a strong acid. Acidic solutions have free-floating H+ ions, which would be much easier to extract than molecularly bound H atoms.
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End of line.
Wed, 2016-04-27 08:37
#14
ringringlingling
No, that was not my question
I asked why hydrogen fuel cell manufacturers and alternative energy interests were promoting distilled water electrolysis over salt water electrolysis as a means to provide sustainable fuel, when salt water electrolysis is both more efficient and profitable.
Fri, 2016-04-29 07:00
#15
ThatWhichNeverWas
I've actually had to partially research this for a Uni project.
There are two answers - the first is that Brine Electrolysis isn't easily reversible so it's hard to make a closed loop system. Cracking Pure water would make Hydrogen systems directly rechargeable through solar panels or mains access, making small-scale cost effective operations more feasible.
The other reason is that you can't treat industrial processes as though they were in a vacuum. Cracking Brine may be efficient, but you also need to store, transport and/or process the waste, you need to install appropriate safety measures, and so on. All that additional infrastructure is going to be adding to the energy, material, financial and environmental costs of the process.
Pure water may require more electrical energy but can still win out because of the reduced incidental costs.
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In the past we've had to compensate for weaknesses, finding quick solutions that only benefit a few.
But what if we never need to feel weak or morally conflicted again?
Fri, 2016-04-29 08:24
#16
ringringlingling
Sunk Costs
You're thinking in terms of initial investment, not operating costs or long term profitability. If you can borrow at 3% and see returns of 6%, it doesn't matter how much you borrow, profit is profit, and I'm guessing you make more money cracking brine than you do cracking water.
We have already developed membrane cell electrolysis cells which could probably be adapted to smaller scale applications. Even if centralized production proves more efficient, anything is better than the toxic mercury cells being used in some parts of the world.
Imagine if you built a desalinization plant to deliver clean water and used filtration to create a brine pool to crack with your chemical plant. Not only are you keeping the brine from going back into the ocean, you are profiting off the byproduct!
Wed, 2016-05-04 02:06
#17
MrWigggles
Then there are hidden
Then there are hidden barriers that we're not privy to, or you're grossly underestimating ring ring ling ling, the cost of creating that infrastructure.
Fri, 2016-05-13 06:28
#18
ThatWhichNeverWas
Things get damaged, things get broken...
It's not just the initial investment, although that does make it harder to get funding.
The problem is that there's no such thing as "just" an initial investment. A larger installation means more maintenance costs, more employees to run it and probably more tax to pay for the land.
Storing, processing or moving waste also requires energy/money to pump, compress or move it, or whatever else is necessary. The fact that the substances are corrosive makes it worse, because that usually means more stringent (aka costly) safety requirements and a shorter turnover rate on the facility's components.
Essentially, this is the difference between Science and Engineering. You can't just consider the effectiveness of the process, you have to think about the entire life cycle of the product.
—
In the past we've had to compensate for weaknesses, finding quick solutions that only benefit a few.
But what if we never need to feel weak or morally conflicted again?