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
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just need to click on the little icon in the corner or on that icon there. As always thanks
very much for watching. Have a great week and remember to just have a think. See you next week