Well here I am again coming at you with yet
another video about hydrogen, which if you've watched some of my previous offerings on the
subject you'll know is an element with great potential but also a whole raft of issues and
challenges on a practical level. Hydrogen is the most plentiful element in the universe, which
is nice. But here on earth it doesn't tend to float around on its own. It has to be forced away
from the other elements it's reacted with, which currently either means hitting fossil methane gas
with high pressure steam to break apart the carbon and hydrogen atoms, which is a process that
generates more greenhouse gases than burning diesel, or it has to be separated from oxygen
atoms in water via the process of electrolysis, which is much less efficient and currently more
than twice as expensive at about five dollars a kilogram compared to one or two dollars a kilogram
for hydrogen from steam reforming methane. Once you've got your hydrogen you have to store it
somewhere for transport and all that sort of stuff. As an energy carrier hydrogen contains
120 megajoules in every kilogram compared to only 44 megajoules in a kilogram of gasoline.
That's why it's such an attractive prize. But at normal temperature and pressure gasoline is
an easily manageable liquid whereas hydrogen is a gas with a very low volumetric energy
density. That means hydrogen either has to be compressed to about 700 times atmospheric pressure
to get it into manageable sized containers or it has to be cryogenically chilled down to
minus 253 degrees Celsius so that it condenses into a liquid. That's only 20 degrees above
absolute zero. Both those processes need a lot of energy and expensive infrastructure, so I suppose
it's not surprising that clever science boffins in laboratories all over the world have been trying
to develop alternative methods for liberating and storing this potentially transformative
element. And now a couple of research teams reckon they've worked out how to store hydrogen
safely and more or less indefinitely as a powder. Hello and welcome to Just Have a Think.
If you're a regular viewer of the channel you'll know that over the years we've looked
at all sorts of ways of storing and converting energy from electrochemical reactions in various
battery technologies to thermochemical reactions in energy storage media. Now we've got a new
term to add to the lexicon - Mechanochemistry. It's a phrase that came to prominence only a
few years ago when this paper described how the rather unfortunately titled process of dry
ball milling could be used to strip graphite down into graphene. Now a group of research
scientists from Deakin University in Australia has embraced this technology and
combined it with good old Nanotechnology to achieve separation of gases without the
need for heat or light or an electrochemical reaction. Their initial focus was to find
a way of simplifying the separation of hydrocarbon gases like alkene or olefin and
paraffin from petroleum which the fossil fuel industry currently achieves in distilleries
by cryogenically cooling everything down into a liquid and then reheating the mixture and
siphoning off each gas as it evaporates at its own specific boiling point. That's quite smart science
but it's also very expensive and energy intensive. The process that the Deakin team have
developed essentially involves a cylinder containing Nano sheets of boron nitride powder and
a bunch of steel balls. The breakthrough discovery that the team have identified is that when defects
are present at the edges and within the main body of boron nitride nanosheets they act like a
catalyst to accelerate the absorption of gas. By rotating the cylinder and allowing the steel
balls to tumble onto the powder the researchers have been able to greatly increase the number
of these catalytic defects in the material. When a mixture of olefin and paraffin gas
is introduced at room temperature and normal atmospheric pressure the nanoparticles of boron
nitride selectively absorb much greater quantity of olefin gas over paraffin gas. That means at the
end of the process pure paraffin gas can simply be siphoned off and the olefin can be recovered from
the boron nitride powder via a low temperature heating process. It's really very simple indeed
and according to the research team this scalable mechanochemical process offers substantial
energy savings over the existing technology. It's not a particularly quick process. It can
take more than 20 hours for olefins to be fully absorbed. But the team found that rotating their
cylinder for that length of time only used about 32 cents worth of energy. According to the
paper the full scale process is estimated to consume 76.8 kilojoules per second to separate a
thousand litres of an olefin / paraffin mixture, which is two orders less than the cryogenic
distillation process. Now you know me, I'm not one to arbitrarily promote anything that
might be perceived as being advantageous to the fossil fuel industry, but if this method could be
scaled up and used in the petrochemical industry then it displaces a process that, according to
a report by the Oak Ridge National Laboratory, accounts for as much as 15 percent of all
energy consumption in the United States, and presumably a similar high tariff
at distilleries elsewhere in the world. Technology writer Loz Blain spoke to the paper's
co-author professor Ian Chen for a recent article that you can find at Newatlas.com and I'll leave
a link to that article in the description section below. Chen told Blain that although their
research paper focuses on paraffin and olefin they realised that the process could also be used
to absorb and store relatively high quantities of hydrogen gas... "it doesn't require a lot
of energy" Chen explained "and it's safe under normal conditions. It's quite stable and the
hydrogen won't be released unless it's heated to a couple of hundred degrees" Even with that heating
requirement at the end to liberate the hydrogen from the boron nitride powder, Chen says their
initial small-scale experiments with hydrogen suggest that their process would use only about a
quarter of the energy needed to compress the gas to 700 bar. That can most likely be improved as
the system scales up and the operating parameters are optimized, plus in relative terms the more gas
you store the less energy you need to release it. Tests indicate that each gram of boron
nitride powder stores about as much hydrogen as 11 centilitres or just under four fluid
ounces of compressed hydrogen gas, which the team claimed to be about double the capacity
of other solid-state hydrogen storage methods. The boron nitride powder isn't an infinitely
reusable material though of course. It is pretty stable but the process of pummelling it with steel
balls does mean it loses about one to two percent of its storage capacity on every cycle. The Deakin
team are now looking at ways of treating the spent powder to restore its absorption levels.
That's by no means a done deal just yet though and there's still quite a bit of work
required to prove out an effective process. so we're definitely not at the stage where we all
need to be getting giddy with excitement just yet. As is so often the case there will most likely be
several years of further research and development before we see this process at industrial scale in
the real world. And that probably holds true for another completely different powdered hydrogen
storage technology that was announced in the very same week as the Deakin paper was published.
This one comes from a company called Epro Advanced Technology or EAT, based in Hong Kong, and it
involves storing hydrogen in a powder by not storing hydrogen in a powder at all! Yeah, I know.
Now I'm going to share the very brief explanation that the company provides for how the technology
works but I reserve the right to retain a healthy level of journalistic scepticism about this one
until it's been road tested and peer reviewed in the real world because it sounds a little bit
too good to be true in my view. And as you good folks are constantly reminding me, if something
sounds too good to be true then it probably is. Anyway, see what you think, and I'll be interested
in your comments and feedback at the end. The company are pitching their
technology as the 'easiest safest and most economical way to generate and
deliver hydrogen that the world has ever seen.' So you know, there's no shortage of confidence
that's for sure! What they've developed is a material they're calling Si + which is apparently
a very porous version of silicon powder that, when exposed to water, reacts to form silicon
dioxide or silica and hydrogen according to this balanced equation that your chemistry teacher at
school would have happily been able to show you, so nothing new there. They don't exactly say what
they do to the silicon to make it super porous but their promo video suggests it involves the
input of electrical energy somewhere along the line. The video shows the processed powder being
poured into a flask of water and hydrogen bubbling out at the other end to charge up a one kilowatt
fuel cell. They plan to produce a small system for domestic homes that could charge a five kilowatt
fuel cell which would be enough to run domestic appliances. They're also hoping to break into the
global market as an ultra safe cost competitive storage and transport medium for hydrogen.
It'll be safe because, as I mentioned earlier, the powder doesn't actually store anything at
all! Just add water at the end and, hey presto, instant hydrogen! They're not clear what the
end user is supposed to do with all the silicon dioxide they'll be left with. That may not be a
problem for anyone living next to a beach because it's essentially no more than a component of sand.
But not everyone has that luxury do they? So there would need to be some sort of collection facility
which could get pretty cumbersome and expensive. Nevertheless the company plans to deliver
domestic generators into the European market and commercial generators in
Hong Kong at some point in 2023 and they're apparently talking to the Hong Kong
airport authority about replacing backup diesel generators and providing a hydrogen refuelling
station at Hong Kong International Airport. I'm not going to hold my breath on this particular
technology, but there's no doubt that along with the high cost of production in the first place,
the safe, economical storage and transport of green hydrogen is a major obstacle holding back
its mass adoption. So I guess it's got to be encouraging to see the development of alternative
hydrogen storage solutions like these and others like this solid-state metal hydride technology
from a company called GKN Hydrogen in Germany, which is something we may look at
in more detail in a future video. That's it for this week though. I'm sure many of
you have lots to say on this subject so as always, if you do, feel free to leave your thoughts in the
comments section below. In the meantime, a massive thank you as always to our fantastic Patreon
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remember to just have a think. See you next week
