Hydrogen, storage and production: evolution and H2 technologies

[Obamot]

All the yield data are missing, but we know very exactly the mass of hydrogen stored in 1 kg of formic acid and the maximum energy that can be produced using this hydrogen.

Starting from formic acid, we therefore recover to the maximum 1,4 KWh / Kilo.

If EPFL can do better, it is not on the catalyzed dissociation of formic acid that they must write an article, but on their new method of using hydrogen.

Ouch ... dumped!

But here are still the thermochemical and physical properties of HCOOH:

it's basic thermochemistry.

Still, I don't know where the coef comes from. 14!?!

For me it is, at worst, on the mass, a coef. under 9 ...

PCI by mass: 6.4 / 1.22 = 5.2 MJ per kg of acid = 1.4 kWh
PCI mass kerosen = 12 kWh or 8.6 times better than acid ...

[Christophe]

These are not the numbers we are talking about.

There is no PCI indicated because it is not the purpose of formic acid, it is not a fuel ...

What we calculate is a "virtual PCI on the use of H2" contained in the acid ... starting from the mass of extractable H2, no more and no less ...

On the other hand, it is obviously assumed that the extraction of the H2 from the acid does not cost a joule !!

Then it can be an exothermic reaction ... for that you need the details as you say. When in doubt, this extraction is assumed to be null.

[Christophe]

If EPFL can do better, it is not on the catalyzed dissociation of formic acid that they must write an article, but on their new method of using hydrogen.

You just touch up what I just answered Obamot: what is the energy cost of this catalyzed dissociation (which I call extraction)? Endo or exothermic?

The new method of using H2 will not change the problem of the mass of formic acid: we are talking about PCI, not useful energy ...

[Obamot]

... yes I saw, dslé I was editing.

OK I understand. Hence the reasoning to say that it will not be for transport, but for an in-situ installation.

[Christophe]

You did well to edit because finally formic acid is not so "little dangerous" as that!

69 ° C flash point is not far from that of fuel oil (55-60 ° C)
14% to 34% vol of flammability is huge as a range of flammability.

To compare with fuel oil:
http://fr.wikipedia.org/wiki/Gazole

lower: 0,6% vol
upper: 6,5% vol

The advantage of the acid is that its low limit (LEL) is very high (which leaves time to protect ...):

http://fr.wikipedia.org/wiki/Limite_d%2 ... ivit%C3%A9

Compare to natural gas

Natural gas 5% 15%

But here are still the thermochemical and physical properties of HCOOH:

ps: you should put the link to the wiki page

[Christophe]

OK I understand. Hence the reasoning to say that it will not be for transport, but for an in-situ installation.

That's all we wanted to tell you ... in this sense the journalist who speaks of "acid car" got a little carried away ... I think ...

[Obamot]

No, no, it is themselves (EPFL) who speak ...

On the trail of exothermic reactions of HCOOH:

Chemical-physical properties

The OO bond is unstable due to the degree of oxidation of oxygen equal to -1. The functional group is thus very reactive and can react as an oxidant (most common case) or reducing (for some compounds such as hydrogen peroxide) in order to reach more stable degrees of oxidation. Another property of this group is its ability to form radicals by homolytic cleavage of the OO bond. This cleavage can be initiated thermally, by catalysis or by UV.

Indeed, this is the case in polymerization reactions, the zone having undergone the reaction suddenly becomes boiling: impossible to touch it ...

Maybe there is something? The possibilities are varied in this family ...

Source of carboxylic acid:
http://fr.wikipedia.org/wiki/Acide_carboxylique

@ ++

[dedeleco]

Christophe is right to ask the question:

Still, I don't know where the coef comes from. 14!?!

because when I read it again it is clear that, disturbed for something else, afterwards, believing that I had done the calculation, I quickly copied a figure on my calculator which was wrong on my post:
https://www.econologie.com/forums/post204835.html#204835
and I corrected all my posts of this error:
the correct number is 9,7 !!
I invite you to correct the other posts that quote me !!
It is good that everything is checked, discussed, analyzed to arrive at reality.
Also I put my calculation which is the one with the enthalpy energy balance with the tables, which corresponds to the best possible, without losses, but in reality it is less with yields far from 100%.
I invite Obamot to read the wiki courses in Thermodynamics and Chemistry on the enthalpies for good orientation, but it is the same as for the gravitational energy at the concept level.

In particular it allows to know if a reaction is endothermic or exothermic, and the decompsosition of formic and endothermic acid slightly, as I note on my post with the enthalpic values ​​of HCOOH compared to its decomposition CO2 + H2 by summing the enthalpies:
the CO2 produced -393,5KJ / mole and H2 gas with + 0,9KJ / mole gives in enthalpy energy: -393,5 + 0,9 = -392.6KJ / mole to be compared to the lower formation energy recovered during the synthesis of formic acid of -425KJ / mole and therefore to decompose this acid it is necessary to supply 425-392,6 = 32,4KJ / mole in energy, for example the reaction on catalyst absorbs heat. (I invite you to check that I have copied the tables and not forgotten something).
The enthalpy tables similar to altitude tables, allow to calculate the energies of chemical reactions which are found in heat and sometimes in work or electricity.

43,15Mj / kg of Kerosene against -425KJ / mole for formic acid, i.e. by 46,02g and with for the CO2 produced -393,5KJ / mole and H2 gas with + 0,9KJ / mole indicates that the decomposition of l formic acid requires a little energy of 425-393,5 + 0,9 = 32,4KJ / mole not considered by Gaston, compared to 286 or 237KJ / mole, which reduces to 237-32,4 = 204,6 , 2KJ / mole of H53, i.e. 2g per liter of formic and 2g per mole of HXNUMX gives:
204,6/2x53=5421KJ/l soit 1,5KWh/litre

... one mole of H2 weighs 2g and therefore 53g contains 53/2 = 26,5moles of H2
In addition it is 53g / liter with density of 1,22Kg / liter which gives in H2 43,44g / Kg of formic acid.
therefore for an airplane by weight, that is 5421 / 1.22 = 4443KJ / kilo = 1,234KWh / Kilo of formic.

This is to be compared to Kerosene at 43,15KJ / Kg or 12KWh / Kilo and therefore with a factor a little more 12 / 1.234 = 9,7 times less energy per kilo of formic acid compared to the kilo of kerosene !!
For an airplane, the same energy requires 9,7 times more weight of formic acid than kerosene. !!
Even by improving the efficiency on an electric aircraft, compared to a kerosene reactor, we will remain far from the lightness of kerosene fuel.

read:
http://fr.wikipedia.org/wiki/Acide_m%C3 ... o%C3%AFque
and especially even in English:
http://fr.wikipedia.org/wiki/Enthalpie_ ... _formation
http://en.wikipedia.org/wiki/Standard_e ... _formation
http://fr.wikipedia.org/wiki/Dihydrog%C3%A8ne

Otherwise, as cited by Obamot, organic acids are reactive all the more as the enthalpy balance gives energy.

Finally the quote from Obamot:

Chemical-physical properties
OO link is unstable due to the degree of oxidation of oxygen equal to -1. The functional group is thus very reactive and can react as an oxidant (most common case) or reducing (for some compounds such as hydrogen peroxide) in order to reach more stable degrees of oxidation. Another property of this group is its ability to form radicals by homolytic cleavage of the OO bond. This cleavage can be initiated thermally, by catalysis or by UV.

is not found in organic carboxylic acid formic or methanoic acid:
http://fr.wikipedia.org/wiki/Acide_carboxylique
because there is no OO link !!
but in peroxides because two oxygen can have very different arrangements:
http://fr.wikipedia.org/wiki/Peroxyde
http://en.wikipedia.org/wiki/Peroxide
very very responsive, very different, formic acid, nothing like hydrogen peroxide is with ordinary water, fabric bleaches as effective as bleach, and sometimes explosive (too old ethers which have injured and killed chemists), very useful in chemistry given their reactivity, etc .....

Fortunately, because the EPFL car would be an explosive terrorist Kamikaze type!

Carefully read the wikipedia links !!!

[BobFuck]

Hop, I am going back to this subject because Obamot groans that nobody is interested in it.

Well, formic acid is bullshit of course.

http://www.carbonrecycling.is/

Icelanders dig: they find hot water, in hot water there is CO2 in quantity. It's hot Perrier, by and large.

Heat => Turbine => Electricity
Electricity + Water + Heat => H2
H2 + CO2 => Methanol

In other words, they make methanol (an excellent fuel, and an excellent chemical base, unlike non-transportable hydrogen) with hot water.

Couillu. The factory has been operating for 1 year, apparently it works.

Morality: CO2 will probably become a recoverable waste (and therefore profitable, and therefore recycled) long before the warmists have managed to prove anything.

In truth, I tell you, we face a great danger: when stateless capitalism has extracted the last mole of CO2 from the atmosphere to sell it transformed into fuel or plastics, it will be the great glaciation! Quickly, you have to tax all that, set up a stock exchange for morally fair trade, etc.

[Obamot]

And no, it is not! we already talked about it on page 2, read again:

https://www.econologie.com/forums/post204712.html#204712

We are waiting for Bob to say: how much does it cost to do it, such as what is the catalyst used ... and that he gives performance values, paskeu otherwise it is he who tells us c .... ries . Ah, that's smart.

Not my quote by the way, DD quoted it, but it was wiki.

So no, I'm not complaining, I'm not taking a stand, I'm asking our chemist

And if he says ksébien there, I will not say the opposite ...

Bob makes it difficult with his Co2, and how does he store his methanol safely, and what if he doesn't have hot water:

Store energy from the Sun with water and rust

EPFL researchers produce hydrogen with sun, water and ... rust! They pave the way for an economical and ecological solution for storing renewable energies.

How to store solar energy, make it available at any time of the day and, of course, at night? EPFL researchers are developing a technology that transforms light into a clean fuel with a carbon neutral balance: hydrogen. The basic ingredients of the recipe are water and metal oxides - for example iron oxide, or more prosaically rust. It was on purpose that Kevin Sivula and his colleagues limited themselves to extremely inexpensive materials and manufacturing techniques. Scientists plan to pave the way for economically viable solar hydrogen. This device, still experimental, is the subject of a publication in Nature Photonics.

The idea of ​​converting solar energy to hydrogen is not new. Researchers have been working on it for more than four decades. It was during the 90s that EPFL launched this niche, with the work of Michael Grätzel. In collaboration with a colleague from the University of Geneva, he invented a kind of solar cell known as the “photoelectrochemical cell” (PEC) capable of producing hydrogen directly from water. The prototype takes advantage of the principles of the dye solar cell - invented by the same Michael Grätzel - combined with an oxide-based semiconductor.

The device is fully integrated. The electrons produced are used directly to release oxygen and hydrogen from the water. In the same bath, two separate layers are responsible for generating electrons when stimulated by light: a semiconductor, capable of releasing oxygen, and a dye cell, which is responsible for releasing hydrogen.

The most expensive material: the glass plate!
For his latest prototype, Kevin Sivula's team set out to solve the main problem of PEC technology, namely cost. "An American team managed to achieve an impressive 12,4% return," says Kevin Sivula. The system is very interesting on a theoretical level, but with their method, 10 square centimeters of surface cost around 10'000 dollars to produce. ”

From the outset, the researchers imposed themselves on using only affordable materials and techniques. A size constraint. “The most expensive material in our device is the glass plate!” Explains Kevin Sivula. The yield is still low - between 1,4 and 3,6%, depending on the various prototypes tested. But the potential of the technology is considerable. “With our cheapest concept, based on iron oxide, we can hope to reach a yield of 10% in a few years, at a cost not exceeding 80 dollars per square meter. At this price, we will be competitive with traditional methods of extracting hydrogen. ”

The semiconductor, responsible for releasing oxygen, is none other than iron oxide. “It is an abundant and stable material. No chance it will rust any more. But it's also one of the worst semiconductors there is! ” jokes Kevin Sivula.

Nano-rust doped with silicon
This is why the iron oxide used by the researchers is a little more elaborate than the rust of an old nail. Nanostructured, doped with silicon oxide, covered with a nanometric layer of aluminum oxide and cobalt… So many treatments which optimize the electrochemical properties of the material, but which remain simple to apply. "We needed an easy method, where we could just dip the material or paint it."

The second part of the device consists of a dye and titanium dioxide - the basic ingredients of the dye solar cell. This second layer allows the electrons transferred by the iron oxide to gain enough energy to extract the hydrogen from the water.

Promising potential - up to 16%
By 10% in a few years, Kevin Sivula estimates that he will be able to achieve a return of 16% in the end, while keeping the low-cost logic that makes the whole point of the approach. By allowing solar energy to be stored at a lower cost, the system developed at EPFL could considerably increase the potential of this sector.

http://actu.epfl.ch/news/stocker-l-ener ... -et-de-la/