Is It Possible to Make Hydrogen from Seawater?

Sure; how did you not know this already?

Yes, Boss. Of course it is possible. You need to consider the economics.

Obtaining drinking water from seawater is currently done by two main processes: evaporation and reverse osmosis[RO]. Of the two, RO is cheaper at around 3.5kWh/m³ using pressure exchanger devices. If waste heat from, say, a big marine engine is in short supply, RO is the better option.

Hydrogen is produced by electrolysis of water, at the negative electrode. When it is burnt in an engine, one can only recover a fraction of the energy that has been used to create it. Thermodynamics says so; it's the way this universe works.

There are articles in Wikipedia on all these topics.

Where are we going with this?

"Where are we going with this?"

No where productive.

So what else is new?

Yes surely you can, NaOH(Caustic Soda), HCl(Hydrochloric Acid), H could be derived from processing sea water plus electricity. Well, actually brine(de-inoized H2O+mineral Salt) is used to manufacture above.

Since I have posted the question I had found a paper from the Higher Technological Institute in Egypt. They list the byproducts of hydrolosis with seawater as H2,Cl2, O2, and NaOCl. But I dont see NaOH or HCl. That would be interesting if what you say is also present. Thanks.

I briefly toyed with the idea of de-mineralizing my pool water. The thought was to plate the minerals out onto a screen. To try this I took a 1 foot square of metal screen, mounted it in a wooden frame and hooked a battery charger to both sides of the screen.

I had to experiment with charger clamp spacing to keep the charger from tripping.

It worked, sort of, but a by-product was also gas generation.

You might experiment with this set up and collect some of the gas to see if it will burn.

I abandoned that experiment, had the pool drained, completely re-done and filled with "new" water.

(Those of you who are following my Oven/Cook Top Temperature thread will understand if I explain that my wife thought the pool plaster "had lost its sparkle". "And look, the cool decking is cracked")

Anyway, you can generate some gas using this method.

NaOH & HCl are not present for the simple fact that these strong ions are completely disassociated in a normal water dilution such as seawater- you have the Cl-, -OH & H+, Na+ ions. If a membrane that is porous to water (but not these ions) is placed between the electrodes to seal them off, one side will become basic & the other acidic as a result of this (the extent depends on the salt concentrations, other minerals present, phase of the moon...). The Downs cell is an industrial version of this that produces these products, or chlorine & sodium frrom fused salt.

Dijeferidu, I think you are going in the right direction, not only to produce hydrogen and water, but other substances as possible, and although your detractors have much weight in their arguments that it is un-economic and in-efficient, there are undoubtedly situations where your proposal could work well. Such a situation would be where there is a fresh water shortage, a requirement for electrical energy, - such as a desert, (often found on the western side of continents) sea water, and abundant natural energy. There are several situations similiar to that described above where there are strong tidal flows, this movement of vast amounts of seawater is now being harnessed by underwater tidal generators, - eg http://www.bbc.co.uk/news/uk-scotland-18096372 - the science for this is well known, the tides can be predicted thousands of years ahead and the engineering side, although still in an early development stage is out of it's infancy now and growing strong. To an extent it is supported by the rapidly growing wind energy industry, the which now produces 2% of the worlds electricity and seems to be doubling every three years, according to BP, http://www.bp.com/extendedsectiongenericarticle.do?categoryId=9041566&contentId=7075262 There is much similiarity between the technology in the new offshore wind farms and the tidal generators, - some even use the same blades! and certainly in the background technology etc, and there are advantages, wind turbines need to be at least a blade diameter apart and preferable two, to not interfere with each others wind flow, but underwater they can be much closer, the wind being a gentleman who goes around rather than involving in troublesome situations but the water being much closer and more snuggly, (excuse poetical license as I don't know the flow equations) so towers can hold more turbines and also often not be so high, (thus cheaper) and the water normally only goes in two directions so siting is easier. Well, in such a situation where the desert area has not much natural energy resources but there is lots of energy from tidal flow, and there is a good reason to live there, - minerals, military, etc, - (so efficiency is not an issue but the most efficient for the situation is the issue) there may be the solution to many problems, - the hydrogen can initially be stored in old time guided column tanks, as it is not explosive till mixed with oxygen, it is easy to transport, being a gas with low friction when flowing through pipes, unlike oil or water, - used for heating and electrical generation initially, and when things get more developed with compressors and such it can be used for transport fuel as there are now quite well developed Hydrogen powered cars. Given that folk would use less electricity at night and there would be times when huge extra capacity lay otherwise un-utilised, producing the other chemicals you mention plus industries that need pure oxygen in refining or combustion would all benefit, helping to defray the initial costs and expansion costs. Cheers, Geoff Thomas.

yes you can but its not economical ,many have tried this and many other options like

carbide but the cost will be more with less output so not practical

Many years ago I got involved with an international team discussing Water and Hydrogen production.

The main outcomes were that the energy requirements of each plant would be substantial and ideally would use separate nuclear power stations for each purpose.

The second and most critical outcome was a major doubt on the viability of Hydrogen transmision. I forget the numbers but we currently pipe Natural Gas around the world and this has a known leakage factor, providing that the engineering and maintenance are spot on. The size of the Hydrogen molecule relative to the size of the Methane molecule - assume for this pupose we are talking 100:1 and the leakage rate will be inversley proportional to molecule size or some power of that ratio - again I forget the detail.

Perhaps the simplest way to look at it is to assume that we have to have much shorter pipes ( 100:1) to carry Hydrogen vis a vis Methane. Yes folk have discussed pipe lining but this is difficult at joints/flanges/bends/splitters etc and the whole exercise gets rapidly out of kilter.

Unless, of course, someone has invented a better rabbitt since then?

So, yes you can make Hydrogen in a number of ways but you have to remember that transmitting Hydrogen is transmitting energy and every molecule that you lose in the transmission is another nail in the coffin of Hydrogen Power.

Regards

Sleepy

Much progress has been made storing Hydrogen in a solid form in metal hydrides. Nano technology is also being developed to store it economically using C60.

As previously stated,transportation in gas form is wasteful, and there is hardly anything that can contain hydrogen without some leakage, so solid seems to be the direction research is moving at present time.

Ammonia Borane comes to mind.Google it for more info.

In certain conditions efficiency of conversion is not as important as availability of energy on demand.

As previously stated, when there is excess free energy,like wind or wave, then the question becomes ROI,which almost any company will jump on if it is 5 years or less.

Once the infrastructure is paid for, maintenance and management become primary expenses.

An off shore nuclear plant would be ideal,but the ecological impact potential and public outcry would make that option nearly impossible.

By just beginning your study of this technology, you are open to ideas that would be discarded off hand by experts in the field, so don't be discouraged by naysayers.

"If man were meant to fly..." .... "A steam boat, are you crazy?" .... "Fulton's Folley"....

Remember, and Exspurt is simply a drip under pressure.

A fresh set of eyes and a mind unencumbered by impossibilities can accomplish much.

Good luck.

I think the only time using energy to create hydrogen might practical would be if you needed a combustible gas and none was available, and you have vast resources for electricity . in the desert perhaps you could use a vast solar pv array to create the energy to create the hydrogen by electrolysis, but if doing that why not just use the energy from the sun. as for drinking water, create a solar concentrator and use that to create steam from the seawater, then use the steam to run turbines then condense it to potable water. Solar energy itself is free, so why not harness it. they use solar concentrators to run stirling engines, to create steam by using molten salts, so why not use the sun in those environments that have the availability, to create potable water?

John Kanzius used radio waves to produce hydrogen from saltwater. He was trying to find a cure for cancer using radio waves and he found that these can also separate hydrogen from water. The water actually burned while running the radio waves through the glass of saltwater. It works only with saltwater. If you're near the sea you have plenty of saltwater but you can just put salt in plain tap water and it still works. Unfortunately, John Kanzius died before he can find the cure for cancer.

Remeber that any gas that has been through a machine will be contaminated with something or other (probably lubricant) from the machine and not be potable without some form of decontamination. The water vapour that is condensed straight from burning hydrogen in air could be formed without this contamination.

Thank you Ptrend. That is interesting. I had had that concern.

About 20 years ago, I saw a winner of a high school science project making hydrogen directly from light.It was very simple,but there must have been some reason it was not made commercially.It consisted simply of a glass tube containing iron powder and water.When light struck it, hydrogen bubbled out.

I realize that the iron powder would eventually need to be replenished,but with modern advances in chemistry and nano tech it may prove to be viable, but as yet, I have seen nothing.

Anyone else hear of this?

I know that I've thought about the incorporation of iron myself (being that it's one of the most abundant elements on our planet).