Australian scientists say they've made a "eureka moment" breakthrough in gas separation and storage that could radically reduce energy use in the petrochemical industry, while making hydrogen much easier and safer to store and transport in a powder.
Nanotechnology researchers, based at Deakin University's Institute for Frontier Materials, claim to have found a super-efficient way to mechanochemically trap and hold gases in powders, with potentially enormous and wide-ranging industrial implications.
Mechanochemistry is a relatively recently coined term, referring to chemical reactions that are triggered by mechanical forces as opposed to heat, light, or electric potential differences. In this case, the mechanical force is supplied by ball milling – a low-energy grinding process in which a cylinder containing steel balls is rotated such that the balls roll up the side, then drop back down again, crushing and rolling over the material inside.
The team has demonstrated that grinding certain amounts of certain powders with precise pressure levels of certain gases can trigger a mechanochemical reaction that absorbs the gas into the powder and stores it there, giving you what's essentially a solid-state storage medium that can hold the gases safely at room temperature until they're needed. The gases can be released as required, by heating the powder up to a certain point.
The process is repeatable, and Professor Ian Chen, co-author on the new study published in the journal Materials Today, tells us via phone that the boron nitride powder used in the first experiments only loses "about a couple of percent" of its absorption capability each storage and release cycle. "Boron nitride is very stable," he tells us, "and graphene too. We're looking at a restoration treatment that can clean the powders and restore their absorption levels, but we need to prove that it'll work."
The results are absolutely remarkable from a numbers standpoint. This process, for example, could separate hydrocarbon gases out from crude oil using less than 10% of the energy that's needed today. "Currently, the petrol industry uses a cryogenic process," says Chen. "Several gases come up together, so to purify and separate them, they cool everything down to a liquid state at very low temperature, and then heat it all together. Different gases evaporate at different temperatures, and that's how they separate them out."
Cryogenics, of course, is a highly energy-intensive process, and the Deakin team found that its ball milling process could be tuned to separate out gases just as effectively using far less energy. Different gases, they found, are absorbed at different milling intensities, gas pressures and time periods. Once the first gas is absorbed into the powder, it can be removed, and the process can be re-run with a different set of parameters to trap and store the next gas. Likewise, some gases are released from the powders at higher temperatures than others, offering a second way to separate gases if they're stored together.
In the team's experiments, they managed to separate out a combination of alkyne, olefin and paraffin gases using boron nitride powder. The process takes a while – some gases were fully absorbed after two hours, others were still only partially soaked up after 20 hours. But Chen says this should just be a matter of fine-tuning: "We're continuing to work on different gases, using different materials. We hope to have another paper published soon, and we also expect to work with industry on some real practical applications."
[...] The gas separation use case would be a pretty huge advance all by itself, but by storing gas securely in powders, the team believes it's also unlocked a compelling way to store and transport hydrogen, which could play a key role in the coming clean energy transition.
[...] With hydrogen safely stored in the powder, it can be moved around and warehoused extremely easily and safely – this could be a very compelling way to move bulk quantities of hydrogen for export or distribution, since it's both cheaper and easier to handle than gas or liquid, and the equipment needed to release the gas for use at the other end will be pretty simple.
[...] Boron nitride is easily available in industrial quantities, and relatively cheap, but Chen says the technique should work with other materials as well. "We're not limited to boron nitride," he says, "we're just using it as an example. You could also use graphene, to take another example, and we're continuing to investigate other materials."
Clearly, this advance has some potentially enormous implications, which could contribute greatly to energy use reduction, emissions reduction, the green energy transition and even reducing fuel and chemical prices. The team has submitted provisional patent applications, and we look forward to learning what's possible as the method is refined and tailored to useful applications.
Also see: Tech breakthrough could make oil refineries greener, hydrogen safer
Journal Reference: https://doi.org/10.1016/j.mattod.2022.06.004
(Score: 2) by JoeMerchant on Sunday February 22, @03:38AM (16 children)
I was a bit surprised to find that O2 concentrators work based on zeolite (crystalline aluminosilicates - naturally occurring minerals, but we have engineered and manufactured higher performing variations) adsorption beds which suck the Nitrogen out of air, leaving more of everything else by proportion, mostly oxygen.
Makes some sense that there's an H2 variant.
🌻🌻🌻🌻 [google.com]
(Score: 5, Informative) by PhilSalkie on Sunday February 22, @04:09AM (14 children)
Thing is, the zeolite bed doesn't store more than a few seconds' worth of flow - and it's large and heavy in comparison to the flowed gas (think many orders of magnitude heavier.) For this powder storage method to be viable as a transport method, it would have to store a significant fraction of its own weight in H2 - which really seems unlikely. Improving the thermal efficiency of industrial separation technologies, now that's huge in itself, and well worth pursuing. They'll really have to get away from the couple percent storage loss per cycle if it's going to have any significance in other than a static industrial process (where replacing an adsorption bed's filling is a regular sort of thing) - imagine if your car's gasoline tank lost 1% of its volume on each fill-up.
This doesn't get away from all the inconvenient physical realities that make hydrogen an absolutely horrid fuel for transport uses - low amount of chemical energy stored per unit of mass, embrittlement of almost any metal it comes into contact with, penetrates welds and seams, passes past gaskets, burns with an invisible flame, explodes readily.
Cryogenics are a funny realm in the chemical industry - a lot of cryo processes that you'd expect to be expensive aren't, because they use liquid nitrogen - and liquid nitrogen is a byproduct of the manufacture of liquid oxygen and liquid argon, and it's a byproduct that can't be stored for very long. That means that the gas separation firms have to line up a bunch of users who will take all the LN2 they generate, because if it's not sold to customers, it'll just boil off back into the atmosphere. So, the more you agree to take, the cheaper it gets - to the point that it can be much cheaper than paying to run electric refrigeration in industries like food freezing. It can also be an economical method of condensing highly reactive gases which would otherwise require extremely expensive pumps made from specialty materials like tungsten carbide. I've seen non-cryogenic processes which made lots of economic sense suddenly become much less financially attractive once the engineers found out exactly how cheaply LN2 can be obtained in bulk.
(Score: 4, Interesting) by JoeMerchant on Sunday February 22, @04:28AM (12 children)
>hydrogen an absolutely horrid fuel for transport uses
Oh, yeah, all the chemical adsorption "tanks" proposed in the past sounded like really low efficiency batteries to me (why store H2 when you can store more energy in electrons for less weight!)
Then, isn't H2 another "greenhouse gas" - albeit a short lived one, but it leaks like crazy from everything that tries to transport it.
And, do we have to keep re-inventing the Hindenberg, just because H2 is there and "easy" to make?
>exactly how cheaply LN2 can be obtained in bulk.
I wonder, if you let LN2 "boil off" and drive a turbine with the expanding gas, is the stored energy cost-competitive with alternative fuels?
🌻🌻🌻🌻 [google.com]
(Score: 3, Interesting) by pTamok on Sunday February 22, @02:14PM (11 children)
In a word: no.
The problem you have is that when you liquefy a gas by compression, you have to get rid of a lot of heat. This normally is send off to warm up the general environment. When the gas 'boils off', it does so by using heat from the environment. Facilities that re-gasify Liquid Natural Gas [wikipedia.org] shipped in liquid form need access to vast amount of heat to accomplish this. Often, this is extracted from sea-water. Sometimes it can be done by burning some of the natural gas to provide the heat for regasification. This cycle of literally throwing away heat, only to need it back again later makes any energy storage by gas compression/liquefaction very thermodynamically inefficient.
This is not to say that there are not situations where it could be useful: like shipping Liquid Natural Gas, as it is substantially cheaper to ship as a liquid than a gas.
At the other side of the thermodynamic equilibrium, there are such things as fireless locomotives [wikipedia.org] that run on compressed air or steam.
There's a discussion on round-trip efficiency in the Wikipedia article on Compressed-air energy storage [wikipedia.org].
(Score: 3, Interesting) by JoeMerchant on Sunday February 22, @04:22PM (10 children)
> need access to vast amount of heat to accomplish this.
So, like a solar power amplifier?
> any energy storage by gas compression/liquefaction very thermodynamically inefficient.
So, like specialized raw fibers or fabrics may produced in the U.S., shipped to Southeast Asia (e.g., Vietnam or Thailand) for weaving and garment assembly, and then shipped back to North American retail markets... lots of profit in inefficient businesses. (/s but true.)
> steam
So, instead of burning coal to boil water - run the LN2 through the roof of the vehicle, keep the pax cool (desert applications?) and make motive power by releasing more nitrogen into the already 70%+ nitrogen environment. Bonus: you can have "accidents" where compartments containing target undesirables experience sudden de-oxygenation of their breathing air ;-)
Yeah, I don't see it happening any sooner than beaming solar power down from space...
🌻🌻🌻🌻 [google.com]
(Score: 2, Interesting) by pTamok on Sunday February 22, @05:41PM (9 children)
You have to do a lot of work to compress a gas. If you squeeze it, it gets hotter.
You then have two extreme options:
1) Store it in an insulated container, keeping its temperature as high a possible.
2) Remove heat, and store it at its boiling point - there is little point in going below the boiling point, as the density is not going to increase appreciably, and it takes more work.
In the case of (1), when the gas is released, it cools down, usually to ambient temperature when the pressure is ambient.
In the case of (2) , when the liquid is allowed to boil, it extracts energy from the environment so that it heats up to ambient (eventually).
With (1), with a 'large enough' volume - e.g. a salt cavern, you can get a round-trip efficiency of between 60% - 80%. If you are going to use this as an energy storage option, you need a strategy where energy is cheap at the time when you compress and expensive when you release the stored energy, with a price difference being enough to cover the cost of compression/decompression. This is very difficult to do on small-scale installations.
The round-trip efficiency of (2) is even worse. If peak-energy demand prices are high enough, it might be viable, but your lunch might well be eaten by re-purposed old lithium-ion batteries.
There are some fascinating developments in solid-state sodium-ion batteries that could render all this debate moot. I've seen some stuff that, if true, will mean that solid-state sodium-ion batteries will be a game-changing technology in the next couple of years. They have made it out of the lab into real-world applications, to the extent that I'm looking for which company to invest in (I'm probably too late, given that I am extremely conservative financially).
Storing hydrogen in powders could well be very useful in some niche applications: a round-trip efficiency of 95% is not bad. Given how flour and grain are transported in large tankers, a tanker of hydrogen-laden graphene granules could well be a useful way of transporting energy around for certain applications. Less poisonous than methanol, and probably more efficient than making long-chain hydrogenated carbon compounds. I think it would be an unlikely candidate for fuelling combustion-engined vehicles, though.
(Score: 3, Informative) by JoeMerchant on Sunday February 22, @06:27PM (8 children)
Once upon a time, I designed a mechanical system that swung counter-rotating weights around an axis to push things (mostly: a person on a bed) back and forth with a sinusoidal motion. It was hella-efficient, could sling a 150kg person on a 25kg platform back and forth at +/- 1.0gz using a 1/4hp motor (when the gear tolerances were properly set, when it was setup by shop apes it needed 1/2hp - we settled on 3/8hp + shop ape training for the final design.)
We consulted with a "mechanical wunderkind" about alternate ways to implement the design. On our initial visit, I was inspired by his work with engines to design a piston in a sleeve that pushed back and forth - using compressed / decompressed gas as it moved as energy storage springs. On our next meeting when I presented the idea, he immediately dismissed it as impractical - too much energy lost to heat / cold in the compressed / decompressed gas. I wonder, to this day, what insulation of the cylinder sleeves might have achieved, but never got funding to try. He, being mechanical in background, enthusiastically designed a system using electric motors with regenerative braking to sling a mass on a linear bearing end to end under the bed - said mass being significantly smaller than the current rotating masses which are only allowed to swing the width of the bed in circular motions... (same efficiency of counter-mass applies to the air spring...) Anyway, I, being electrical in background and backed up by a room full of his own electrical engineers, dismissed the regenerative braking as hopelessly ineficient - napkin sketch came up with 5hp minimum peak power for the motor to achieve the required oomph moving the bed-passenger mass, and even with good capacitors to hold all that juice, the regen system would easily be burning 1/4-1/2 hp by itself, not to mention overcoming the mechanical frictions involved. Being both a wunderkind and the boss, nobody had the heart to tell him his brainwave was naive to his face - but the message got through eventually - his people sent our people a F-U business proposition that effectively ended the interactions.
Anyway, nothing ever really touched the swinging masses on tapered roller bearings for efficiency or smoothness. I acknowledge the thermal problems with gas springs, but I feel like "perfect" insulation might get you up over 95% efficiency in that particular arrangement - drive the mass with electromagnetic pull as it approaches the center, have dump valve solenoids in the ends for emergency stop. It would be fun to play with, but it would also require much more exotic machine shop equipment than we had access to.
>your lunch might well be eaten by re-purposed old lithium-ion batteries.
Yep.
There are some fascinating developments in solid-state sodium-ion batteries that could be rendered moot by the discovery of low cost of extraction lithium sources, too...
> a tanker of hydrogen-laden graphene granules could well be a useful way of transporting energy around for certain applications.
Everything has its good niches, the problem is when the niches are too small and the economy of scale just doesn't happen: tech that has been scaled to highly efficient (or highly government subsidized) levels just can't be beaten.
🌻🌻🌻🌻 [google.com]
(Score: 1) by pTamok on Monday February 23, @08:59AM (7 children)
Gas springs are well known: the nitrogen-filled hemispheres in certain older models of Citroën cars [wikipedia.org] are very effective, as was the 'hydragas' suspension [wikipedia.org] of Rover Metro.
I guess if the gas being compressed by the piston were in a Dewar flask/Thermos, you could get quite high levels of thermodynamic efficiency. I don't know what the friction losses from the piston would amount to.
If you want to move a 150 kg mass back-and-forth at 1 Hz, why not suspend it on a physical pendulum [harvard.edu], or possibly several (one at each corner, adjusted to be in synchrony (I guess they would self-synchronize))? Not quite sinusoidal, but near enough for government purposes. However, if I were lying on a bed that did that, I would probably get motion sickness. You would need a very small impulse input every so often to keep the magnitude of oscillations up to the level required - power requirement would be minimal - you might even get away with clockwork. Has been implemented as cradle rockers:
https://hackaday.com/2015/11/25/a-clockwork-cradle-is-babys-first-escapement/ [hackaday.com]
https://www.reddit.com/r/clocks/comments/1b0zdg2/antique_clockwork_self_rocking_cradle_advice/ [reddit.com]
(Score: 3, Informative) by JoeMerchant on Monday February 23, @02:20PM (6 children)
The trick on the Gz oscillation is that it needs to impart about 0.25 G of acceleration peak at 2Hz, the pendulum length for 2Hz is 6.2cm and the required range of motion is a total arc length of 3.14 cm, or +/- 14.5 degrees. One issue is: centripetal acceleration. At the bottom of the swing, the rider will experience a different "g-force" (centripetal acceleration) pushing them into their seat, which is approximately 0.13g in this specific configuration - that's a component the linear motion didn't have, and it is pretty significant, might indeed lead to motion sickness. It would be interesting to try to package the "rocking cradle" in such a way that the mattress sits above it all looking like a normal bed.
We expected the motion sickness aspect, but after 30+ elderly riders, only one complained of it, and she complained most loudly before getting on - still convinced it bothered her while she was riding, but rode for 20 minutes without any obvious ill effects. We did have more than one who simply refused to ride, basically by saying "no thanks" before ever getting close to enrolling in the trial. It's conceivable that a "rocking cradle" could work for what we ended up doing, but when the moving bed was in design, we thought we wanted to get up to +/- 1.0 G at a minimum, and getting the pendulum over +/- 0.5 G gets into amusement park ride territory +/- 45 degrees swing angle, definitely not a fun ride like that. We did "shake" a few people up around +/- 1.0 g, think of it like jumping up and down, but on your back... anyway - that never had the desired (passive ventilation) effects, but at 0.2-0.25 G, just about where the bed starts to "move under" the patient while the patient tends to stay stationary above the mattress - we ended up binding people's feet to a footboard - at those levels there's just enough additional "pulsatile flow" of blood in the major blood vessels to release nitric oxide, similar to what happens when you walk or jog. This dilates blood vessels throughout the body, increasing circulation in the major organs (all verified through chemical assay, animal studies confirming increased perfusion of the organs, etc.)
🌻🌻🌻🌻 [google.com]
(Score: 1) by pTamok on Monday February 23, @09:35PM (5 children)
Interesting.
The pendulum length (and length of arc of swing) is tunable when you use a physical pendulum (think solid rod with masses above and below the fulcrum) - it's 6.3 cm only for a simple pendulum (mass on a string).
You can tune the physical pendulum by placing a mass above the fulcrum - by moving it further from the fulcrum, you increase the moment of inertia, and by adding or removing mass, you move the centre of mass, so with a carefully chosen mass placed at the correct distance above the fulcrum, you can get the whatever period you require.
If the bed platform + mattress + bedclothes + patient + suspension rods masses 200 kg, and the length of each suspension rod from its fulcrum is 30cm, with a suspension rod at each corner, extend the rods up from the fulcrum by 50 cm and put a 7 kg mass at the top. Assume each rod is carrying 50 kg of the bed platform. The calculations then give a period for the bed platform of about 1 second. For a 5 degree arc, that gives an arc length of 1/72 of a circle radius 30 cm which is about 2.5 cm. 10 degree arc length is obviously roughly 5cm. Maximum acceleration will be acceleration due to gravity sine (half-arc angle) which will be sin(5 degrees) * g, which is a little under 1/10 g. If you want 0.25 g acceleration, then the half angle needs to be (as you say) sin-1 (0.25) = 14.5 degrees, which is an arc length of about 15 cm. Range of vertical motion would be roughly 1 cm (radius - (cos(half-angle) x radius)).
A (possibly electromechanical) escapement mechanism that gave an impulse at the foot of the bed platform, much like boosting a child's swing, could be all that were needed.
It might be possible to design such a rocking/reciprocating platform that a standard hospital bed could be wheeled onto and fixed in place, but it would likely be unwieldy and heavy.
Another approach would be to put a toothed track on the underside of the bed platform, and rest the bed platform on toothed wheels where the axle is attached to a mechanism that raises and lowers masses. Friction would be greater, but the platform would not rise and fall. The overall construction could well be too heavy. Your design of a small motor would probably be better.
(Score: 3, Informative) by JoeMerchant on Monday February 23, @10:02PM (4 children)
When it was working with a $100 motor and controller from the Grainger catalog, we stopped trying to be more clever...
I was directed to "look into" the use of gyroscopes to try to reduce the mass of our swinging weights (we had two pair of counterrotating weights, each weight was a chunk of steel something like 3" x 4" x 6" swinging on a 1"x4" aluminum arm such that it all fit under the mattress. Counterrotating two weights cancels their reaction side to side. Synchronizing two pair of counterrotating weights and adjusting their phase (by pulling a synchronizing to have different lengths on either side of the pulley pairs to change the phase) allowed pretty precise and reasonably rapid control of the overall Gz amplitude (frequency is, of course, how fast you run the motor spinning the weights)... So... back to the gyroscopes, I told them "everything I learned in physics says: no." but I was encouraged to try things just to see anyway... yeah, no - the gyro effect is pretty nifty at resisting rotation, but it's worthless to generate a translation, and putting the gyro on the rotating arm (a rotation to be resisted?) always ended up cancelling out to do nothing in the end. Maybe something could have been worked out but it would have been hellishly complex as compared with a chunk of steel.
🌻🌻🌻🌻 [google.com]
(Score: 1) by pTamok on Tuesday February 24, @12:04AM (3 children)
USD 100 motor + controller definitely a good option. I just think that if the kinetic energy of the moving bed platform could be scavenged, it could be possible to have a more 'elegant' solution. Perhaps something could be done electromagnetically - capture the energy as the bed-platform is decelerated to a standstill, then use it to re-accelerate in the opposite direction. A motor + controller would, no doubt, be more cost effective.
(Score: 3, Informative) by JoeMerchant on Tuesday February 24, @12:46AM (2 children)
> if the kinetic energy of the moving bed platform could be scavenged
I'm pretty sure the spinning masses were scavenging the kinetic energy, there's no way 1/4hp would have generated those peak accelerations on its own. As a matter of practicality, the rollers it ran on were in a "dish track" that kept it near center even when the ground was a bit off from level, but they only ramped up about 2-3mm in the ranges where the bed normally ran, I think they "peaked" around 6mm just before they hit their end stops.
A very early prototype (not human sized) bolted a dive weight to the outside of a wheel and put a dremel motor shaft up against the tire, then springs were arranged off to the sides of the slider tracks so that they got more and more stretched as it got off center - that one also ran pretty well in the center without really "using" the springs to store energy, they just made sure it stayed in the middle. Nobody believed in the eccentric spinning weight idea until I cobbled that together and put it on the table running.
🌻🌻🌻🌻 [google.com]
(Score: 1) by pTamok on Tuesday February 24, @08:07AM (1 child)
Aaah - a 'dish track' - simple, but effective. Raising 200 Kg a couple of millimetres gives a lot of energy to work with. If the wheels it ran on were truncated cones, it would self-centre on the track too - just like railway wagon/locomotive wheels, and trams. It's always interesting watching people work out how axles with wheels fixed on (no axle-to-wheel bearing) at each end go round curves on tracks1.
1The problem is that when a track follows a curve, by necessity, the inner track has a shorter distance to the centre of curvature than the outer track. This means the outer track is longer than the inner (or the inner shorter than the outer), but if the wheels are fixed to the axle, the inner wheel has to rotate fewer times than the outer wheel to go round the curve: so one of the wheels must slip on the track. In fact, none slip, and the axle doesn't get 'wound-up'2. There is a really neat solution to this apparently impossible problem.
2 The Alvis Stalwart [wikipedia.org] 6-wheel drive amphibious truck suffered from 'wind-up'.
(Score: 3, Informative) by JoeMerchant on Tuesday February 24, @12:23PM
Yeah, we started with 8 skateboard wheels, 4 in the dishes and 4 running near the flat bars supporting the dishes on vertical axes for centering. Ended up "reinventing the wheel" because 8mm axles were too bendy for cantilever duty and packaging requirements wouldn't provide enough bed width to support both ends of the dish wheel axles. Went 12mm with machined Delrin wheels instead.
🌻🌻🌻🌻 [google.com]
(Score: 3, Interesting) by JoeMerchant on Sunday February 22, @04:37AM
And there was a tangential thought about "activated" charcoal - which really does work to absorb all kinds of things, within limits of course. Harry Potter's magical Bezoar definitely needed some magic to have any significant capacity to soak up a potent magical poison.
🌻🌻🌻🌻 [google.com]
(Score: 2) by Freeman on Monday February 23, @05:29PM
Today I learned that the weird sounding mineral in "Planet Crafter" is an actual real thing. I just assumed they made it up, because I hadn't heard of it before.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 3, Informative) by krishnoid on Sunday February 22, @04:06AM (2 children)
I bet France [theguardian.com] would be interested in that.
(Score: 2) by ls671 on Sunday February 22, @02:50PM (1 child)
I wonder if those underground deposit of natural hydrogen might eventually prove Toyota was right. Of course, there would need to be enough of them eventually discovered. I wonder if people have actually ever looked for them. Storing hydrogen is problematic but who knows? I remember seeing buses running on hydrogen stored in solid salts, we'll see I guess.
Everything I write is lies, including this sentence.
(Score: 2) by krishnoid on Monday February 23, @06:00PM
Great idea! I say we set up the mole people near there with a couple chemical labs and some test buses, then let them figure it out and report back to us.
(Score: 3, Interesting) by hopp on Sunday February 22, @05:39AM (1 child)
There was a guy who claimed his corvette could run on "solid state" hydrogen (under room temperature low pressure storage) for some impossibly long distance. He would heat the storage tank to evolve the gas to run the car. Can't seem to find any mention of it now.
(Score: 1) by pTamok on Tuesday February 24, @04:28PM
Under sufficient pressure (between 400-500 gigapascals, around 4 million atmospheres) hydrogen is metallic [wikipedia.org]. It is also metastable, but not down to normal ambient pressure. It's also probably a high-temperature superconductor, with a critical temperature above zero degrees centigrade.
(Score: 3, Touché) by fraxinus-tree on Sunday February 22, @09:41AM
Mechanochemistry is something I read abouth in my childhood - and it was about a reaction well known at least for decades. And, anyone remember NiMH batteries? The letters MH are about the powdered hydrogen. This is how the almost useless NiH chemistry became practical. And, the ball crunchers are at least 2000 years old. What they are not is energy-efficient. Well, they may still be better than the other options when trying to react solids with gases. Good luck cleaning the gas from the powder afterwards...