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It looks like wikipedia was already updated with this information [1]. I personally find their summary to be more informative. “Ammonia can be manufactured fro
by credit_guy 8y ago
It looks like wikipedia was already updated with this information [1]. I personally find their summary to be more informative.
“Ammonia can be manufactured from solar energy, air and water. This is an efficient way to package hydrogen into a chemical that is much cheaper to store and transport than pure hydrogen be it as gas or as liquid. In fact, per volume ammonia holds more hydrogen than does liquid hydrogen. Ammonia may be the key to overcome not only the daily but also the seasonal fluctuations of renewable energy sources.
This approach will solve many of the problems foreseen for the proposed Hydrogen economy, that instead could be replaced by an Ammonia economy, essentially still a hydrogen economy.
In early August 2018, scientists from Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) announced the success of developing a process to release hydrogen from ammonia and harvest that at ultra-high purity as a fuel for cars. This uses a special membrane. Two demonstration fuel cell vehicles have the technology, a Hyundai Nexo and Toyota Mirai”
[1] https://en.m.wikipedia.org/wiki/Ammonia#Energy_carrier https://en.m.wikipedia.org/wiki/Ammonia#Energy_carrier
- amelius 8y agoWhat is the typical energy density of the ammonia using this process? Also what does the chemical reaction look like when harvesting hydrogen from ammonia?
- fsloth 8y ago"what does the chemical reaction look like when harvesting hydrogen from ammonia?" Reverse Haber process maybe? 2NH3 -> N2 + 3H2
- gonvaled 8y agoHow would this work in an ammonia-powered battery?
- gvb 8y agoIt doesn't. The membrane "cracks" the ammonia into N2 and H2. The N2 is released to the atmosphere. The H2 is used in a hydrogen fuel cell to power an electrical drivetrain or in an internal combustion engine with a mechanical drivetrain.
- gonvaled 8y agohow do you regulate the membrane? does it degrade?
- CompelTechnic 8y agoI wonder, does converting ammonia to hydrogen absorb energy or release it? (Ie is it endothermic or exothermic?)
- refurb 8y agoExothermic as the reverse is endothermic.
- marcosdumay 8y agoIt's highly endothermic. Replacing the hydrogen with oxygen is exothermic. So one can create some ammonia-air fuel cell. But reducing it first to push the hydrogen into a fuel cell will almost surely net a negative amount of energy because of the losses.
- darcyparker 8y ago"The raw energy density of liquid ammonia is 11.5 MJ/L,[64] which is about a third that of diesel." https://en.wikipedia.org/wiki/Ammonia#As_a_fuel https://en.wikipedia.org/wiki/Ammonia#As_a_fuel (Note this is energy density by volume, which is the metric most care about. Energy density by weight of H2 gas is great, but the volume is enormous in comparison.) https://en.wikipedia.org/wiki/Hydrogen_storage https://en.wikipedia.org/wiki/Hydrogen_storage Ammonia has been long recognized as a great medium for energy storage and you can generate at the site of electric generation. But the challenge has been extracting the hydrogen from the ammonia. My understanding is that hydrogen crackers exist, but have only been successful commercially at large scale. A portable cracker that you can put on a car that extracts hydrogen on demand from an ammonia storage tank is the innovation we need to see. Apparently there is work in Denmark that looks promising... (And now there is this new membrane technology from Australia.) https://www.mvsengg.com/products/hydrogen/ammonia-cracker/ https://www.mvsengg.com/products/hydrogen/ammonia-cracker/ http://www.ammoniaenergy.org/ammonia-cracking-to-high-purity-hydrogen-for-pem-fuel-cells-in-denmark/ http://www.ammoniaenergy.org/ammonia-cracking-to-high-purity... Personally, I am cheering for ammonia as a storage means. I am not a fan of batteries found in today's electric vehicles because there are too many conflict minerals in them. Maybe Tesla will succeed mining colbat in Colbat Ontario Canada... But until then, it is probably coming from the Congo or Bolivia. https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/ https://www.washingtonpost.com/graphics/business/batteries/c... https://www.bloomberg.com/news/features/2017-10-31/the-canadian-ghost-town-that-tesla-is-bringing-back-to-life https://www.bloomberg.com/news/features/2017-10-31/the-canad...
- amelius 8y ago> "The raw energy density of liquid ammonia is 11.5 MJ/L, which is about a third that of diesel." Yes, but that's assuming you'd burn it, I suppose (not a chemist). In this case, you're extracting H atoms using a different process, and I imagine that this wouldn't utilize the full raw energy density of ammonia.
- pjc50 8y agoLooking at the process as a whole, it is burning - or at least oxidation. Starts with NH3 and ends up with H2O and N2 (preferably not NO2). The energy liberated from the bonds is the same. The amount of energy available at the wheels depends on a lot of fine details of how it's used.
- growlist 8y ago> per volume ammonia holds more hydrogen than does liquid hydrogen How is this possible? Suspect the answer would be way over my head!
- tempestn 8y agoI would expect this is due to the fact that each ammonia molecule contains three hydrogen atoms, whereas a hydrogen molecule contains only two. So liquid ammonia would be expected to contain more hydrogen per volume than liquid hydrogen.
- bayesian_horse 8y agoThat would be true of their gases.
- tempestn 8y agoWouldn't it be true of both liquid and gas?
- maga 8y agoAmmonia is 10x more dense than hydrogen gas at the same temperature/pressure, so you can pack more of it into the same volume.
- Shoh3pif 8y agoArmchair chemistry ahead: Molecular hydrogen is unpolarized while ammonia molecules can establish hydrogen bonds, thus packing them more densely under the same conditions. For really dense hydrogen we would need its metallic form but that requires pressures you might find in the core of jupiter. The electromagnetic force is more convenient than gravity.