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, which could radically reduce energy use in the petrochemical industry, while making hydrogen much easier and safer to store and transport:
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.
[…]
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.”
[…]
“The energy consumed by a 20-hour milling process is US$0.32,” reads the paper. “The ball-milling gas adsorption process is estimated to consume 76.8 KJ/s to separate 1,000 liters (220 gal) of olefin/paraffin mixture, which is two orders less than that of the cryogenic distillation process.”
[…]
Chen tells us the powder can store a hydrogen weight percentage of around 6.5%. “Every one gram of material will store about 0.065 grams of hydrogen,” he says. “That’s already above the 5% target set by the US Department of Energy. And in terms of volume, for every one gram of powder, we wish to store around 50 liters (13.2 gal) of hydrogen in there.”
Indeed, should the team prove these numbers, they’d represent an instant doubling of the best current solid-state hydrogen storage mass fractions, which, according to Air Liquide, can only manage 2-3%.
When did they stop teaching thermodynamics to engineers and scientists?
This sounds like a well-known chemisorption process, the ball mill merely increasing the surface area for adsorption.
The spontaneous, thermodynamically favored reaction is the adsorption itself. The bounding energies have to be overcome by “heating to a certain temperature.” Aye, there’s the rub. We can guarantee that the energy required for desorption is substantial.
So, you have an energy input to promote adsorption and a substantially higher energy input to promote desorption.
The amount of hydrogen stored is trivial amount of hydrogen, 6.5% of the total mass. That is absurd. The energy required to move the whole mass is substantial, and most likely would to be done by truck/train tank car. It would much easier to simply transport natural gas and reform it at the point of use to hydrogen and carbon monoxide.
But even that idea is stupid, because the highly toxic CO must be oxidized to CO2.
None of these wackjob schemes is viable. They all, however, lend themselves to scams, like bitcoins, solar/wind, barn painting (viz. travelers), et al.
As John Michael Greer over at “Ecosophia” points out, there do not have to be easy, cheap, readily available substitutes for petroleum fuels just because we want them and feel like we need them. Personally, unlike Greer, I think that there are probably some substitutes out there, but finding something that is as energy dense, readily available, and relatively cheap as petroleum is not an easy task, and anyone who tells you that it is is probably scamming.
Hydrogen is a very reactive gas and atomically tiny. Hydrogen storage is complicated by these two factors. If it doesn’t react with is container, it creeps out because of its size. Storing it in pellets doesn’t solve those problems. From a humorous point of view this process makes hydrogen pop rocks like the kid’s candy.
Hindenburg anyone? I read a blog about some British engineers looking at replacing domestic gas with hydrogen. From experience they learned to build their experimental apparatus in a small shed in the middle of the countryside and retreat a good distance before pressing the Go button. The shed was usually demolished. Domestic gas used to come off the tail end of petroleum refining. Over more than a century there have been very few disasters. Hydrogen has very low energy density anyway. Adding a filler at a ratio of one active ingredient and twenty sawdust doesn’t improve this. What do we do with the heaps of expended dust afterwards? But as long as the boffins can earn nice grants from hydrogen research, it will go on. As any economist will tell you, incentives matter.
“powdered gases”
mfw