[HN Gopher] Nitrogen electroreduction with almost 100% current-t...
___________________________________________________________________
Nitrogen electroreduction with almost 100% current-to-ammonia
efficiency (2022)
Author : gorpovitch
Score : 250 points
Date : 2023-10-28 21:34 UTC (1 days ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| londons_explore wrote:
| Big if true...
|
| This could enable fertilizer production with no CO2 emissions.
| The numbers in the paper suggest that it might prove cheaper than
| natural gas based production which is common today. Fertilizer
| production is 2.1% of all CO2 emissions right now.
| RetroTechie wrote:
| Not just fertilizer:
|
| _" In addition to its use in the fertilizer and chemical
| industries, ammonia is currently seen as a potential
| replacement for carbon-based fuels and as a carrier for
| worldwide transportation of renewable energy."_
|
| Long-term grid storage?
|
| Publication: 22 July 2022
|
| Anyone know if maybe some pilot / small scale production
| facility has been set up in the mean time?
|
| I've read about a farm that produced its own fertilizer, but
| dunno whether that uses this or some older / unrelated process.
|
| Would be a _huge_ breakthrough in any case.
| fbdab103 wrote:
| Are there power plants today that burn ammonia directly? If
| not, is it a simple/cheap enough conversion?
| praveen9920 wrote:
| It is actually cheaper because of existing infrastructure
| that exists for fertilisers manufacturing.
|
| But the main concern is that ammonia burns slowly. It might
| work in power plants but not in EVs
| thfuran wrote:
| Why would you want to burn ammonia in an electric
| vehicle?
| dexwiz wrote:
| Not sure if they are today, but Toyota is putting a lot of
| effort into ammonia turbines. Also ammonia can be fired
| with coal or natural gas in existing setups. The main issue
| is neutralization of NOx exhaust.
| toomuchtodo wrote:
| While not in mass production, there is strong interest from
| the marine shipping industry. It can be produced near
| ports, and meets the storage and combustion engine
| constraints (similar to diesel) of the use case.
|
| https://spectrum.ieee.org/why-the-shipping-industry-is-
| betti...
|
| https://www.wartsila.com/media/news/30-06-2020-world-s-
| first...
|
| https://www.lr.org/en/about-us/press-listing/press-
| release/i...
|
| https://www.ammoniaenergy.org/articles/maritime-fuel-mix-
| cou...
| Terr_ wrote:
| A sibling comment mentions scrubbing NOx emissions as a
| significant issue, and it strikes me that the
| shipping/cruise industry is already a major polluter in
| that area. (Unlike cars, which must have catalytic
| converters because of local landlubber laws.)
| toomuchtodo wrote:
| High efficiency scrubbing appears to be feasible.
|
| https://pubs.acs.org/doi/10.1021/acs.energyfuels.3c01419
| Terr_ wrote:
| I guess my point is that cleaner technology is already
| being avoided by those companies, because they can save a
| buck by polluting in international waters.
| adrian_b wrote:
| There has been a lot of research in fuel cells that
| generate electricity from ammonia, with much simpler
| storage problems than for hydrogen.
| Projectiboga wrote:
| Yes, fuel cells need more usage as we move away from oil
| & unnatural gas.
| galangalalgol wrote:
| Direct propane fuel cells have some thermal issues, but
| recently there was a breakthrough in propane synthesis
| that would make it efficient to produce. Are ammonia
| fuelcells efficient?
| aifooh7Keew6xoo wrote:
| I'm not sure I'd leap to "much simpler storage problems
| than for hydrogen" for a highly corrosive gas.
|
| The lower explosive limit of hydrogen is ~4%. By
| comparison the 300 ppm immediate danger to life and
| health threshold of ammonia is .03%.
|
| It is intrinsically dangerous, i.e. without a source of
| ignition, at concentrations 2 orders of magnitude lower
| than the LEL of hydrogen.
|
| Not every hydrogen leak is a concern, but just about
| every ammonia leak is.
|
| The established OSHA 15 minute exposure limit for ammonia
| is 35 ppm, 8 hours is 25 ppm.
| thfuran wrote:
| But hydrogen likes to make invisible fires and leak
| through solid steel, and it needs to be ludicrously cold
| to liquify.
| aifooh7Keew6xoo wrote:
| Generally speaking modern hydrogen pressure vessels are
| not metal for this reason, they are composite and not
| affected by embrittlement.
|
| The Toyota Mirai, a production hydrogen car, uses a type
| IV carbon fiber pressure vessel rated for 70 MPa / 10,000
| psi.
|
| Type V are rated for 15,000 psi.
|
| It is not necessary to liquefy hydrogen for adequate
| range in ground transport applications: The Mirai yields
| a 402 mile EPA rated range on gaseous hydrogen.
|
| The tanks weigh 93kg filled with 5.65kg hydrogen,
| yielding an approximately 190 kWh of stored energy.
|
| All without corroding flesh in trace concentrations.
|
| By comparison the Tesla Roadster's 450kg battery pack
| yields a 200 kWh capacity.
|
| Ammonia is and would likely continue to be stored in
| metal pressure vessels as an obvious cost optimization
| and thus would compare unfavorably to hydrogen pressure
| vessels' effective energy density where that area of the
| performance versus cost optimization space is not
| available due to embrittlement.
| ZeroGravitas wrote:
| In Japan they're looking at adding Ammonia co-firing to
| coal plants:
|
| https://about.bnef.com/blog/japans-ammonia-coal-co-firing-
| st...
| pfdietz wrote:
| I think many (most?) combined cycle plants use ammonia to
| destroy NOx in the exhaust (selective catalytic reduction).
| Some diesel cars use this technology as well (using urea
| instead of ammonia).
| jtbayly wrote:
| Farms have been producing their own fertilizer for centuries.
| ;-)
| multiplegeorges wrote:
| Millenia, even.
| RetroTechie wrote:
| Yeah I know. Wasn't talking about that.
|
| https://phys.org/news/2021-02-plasma-technology-world.html
| https://portal.nifa.usda.gov/web/crisprojectpages/1025777-l
| o... https://pubs.acs.org/doi/10.1021/acssuschemeng.2c06357
| (paywalled)
|
| "plasma" and "NOx" seem to be the keywords here (so other
| process than discussed here).
|
| Not at scale (yet), cost unclear. But the technology
| exists, and being improved upon.
| eternauta3k wrote:
| Yes, and yields were crap back then. Guano and then
| synthetic fertilizer changed everything.
| bequanna wrote:
| Well, we don't necessarily need as much storage if we can
| just shift a good amount of demand.
|
| Fertilizer production via this method might be a good fit for
| times when rates are low or even negative due to wind energy
| overproduction during off peak.
| aifooh7Keew6xoo wrote:
| Where are all the people that complain about the dangers and
| impracticality of hydrogen when the topic of using a
| corrosive gas that poses an immediate danger to life and
| health at concentrations as low as 300 ppm as a fuel comes
| up?
|
| They're trying to avoid using the stuff in industrial
| refrigeration it's so nasty, and yet here we are gleefully
| considering rolling down the highway with it in the cheapest
| vessel industry can lobby for strapped to our bum.
|
| I guess the notion has passed so quickly we haven't had time
| for the media to program us with corporate agendas...
| PumpkinSpice wrote:
| I don't think it's realistic as a fuel for cars, but
| "worldwide transportation" means more than that. I suspect
| they're talking about container ships, tankers, and such.
|
| Ammonia is easier to liquify than hydrogen, and is in many
| respects easier to handle. However, it's definitely not
| something you want to have a spill of at a gas station or
| in your garage, and for that reason, it probably won't have
| "consumer" uses.
|
| As far as industrial gasses go, it's certainly nowhere near
| the worst, and there's plenty of ammonia tankers on the
| roads today, but large spills do kill people every now and
| then.
| aifooh7Keew6xoo wrote:
| It is certainly easier to liquefy, I can't argue that
| point.
| justinclift wrote:
| Hmmm, "gas station filled with petrol that explodes" vs
| "gas station filled with hydrogen that explodes".
|
| Being near either one as it explodes would be bad, but I
| wonder which one looks more impressive movie-effects-
| wise? :)
| sfink wrote:
| In my limited understanding, neither one really explodes.
| The petrol one would look like a huge impressive fireball
| that launches a big black mushroom cloud and then just
| burns like crazy. The hydrogen one, if the hydrogen is
| fairly pure, would be like a big faint blue wispy
| fireball, not all that impressive.
|
| If there were an oxidizer in the mix somehow, it would be
| rather more explosive.
| justinclift wrote:
| Cool, thanks. :)
| anon_cow1111 wrote:
| The issue with hydrogen is that it has a fairly wide
| combustion range (meaning the ratio of fuel/air that can
| burn), I can't remember the numbers but it's several
| times greater than other common fuels. The _other_ issue
| with hydrogen is that the combustion happens VERY fast...
| if you ignite gasoline vapor /air in an open 5-gallon
| jug, you have a nice rocket that'll fly 50 feet or so. If
| you ignite hydrogen/air in the same jug, you have
| permanent hearing damage and shards of plastic embedded
| in you.
| amluto wrote:
| If the hydrogen is fairly pure and the amount is question
| is small, then sure: combustion will happen at the
| hydrogen-air interface. If it mixes with air before
| ignition, then it can burn all a once, and Wikipedia
| informs me that "the limits of detonability of hydrogen
| in air are 18.3% to 59% by volume.". Yes, it will
| literally detonate with supersonic flame velocity.
|
| I once got to watch some moderately crazy students fill
| an ordinary party balloon with a stoichiometric mix of
| hydrogen and oxygen at ambient temperature and pressure.
| When it was ignited, the result was extremely impressive.
| No one was injured (because we were all warned to protect
| our ears and open our mouths and balloons don't produce
| significant shrapnel), but the shock wave was not at all
| subtle.
|
| https://en.m.wikipedia.org/wiki/Hydrogen_safety
| ben_w wrote:
| Why is having open mouths important?
| adrianN wrote:
| Less pressure on your eardrums if the shock wave reaches
| them from both sides.
| ben_w wrote:
| Ah. So holding my eustachian tubes open (half way through
| a yawn) would also be a good idea?
| colechristensen wrote:
| Hydrogen is way worse than gasoline or any hydrocarbon.
| It has to be stored at very high pressures and there's no
| practical situation in which it doesn't explode.
| TheSpiceIsLife wrote:
| Toyota have produced a prototype ammonia engine they
| claim is the end of the EV market.
| aaronbrethorst wrote:
| Neat. I look forward to them rolling out a production
| model in 2043.
| jacquesm wrote:
| I look forward to them rolling it out _downwind_.
| _aavaa_ wrote:
| They can keep making claims to cover up their complete
| bungling of their market position.
|
| As for the idea itself. Ammonia as fuel fails the first
| principle of safe design. It's a poisonous _gas_. Using
| it as a fuel is a willingness to trade the safety of
| people for a cheaper fuel.
| jodrellblank wrote:
| The move from cars to SUVs in America was so car
| manufacturers could skip emissions and safety
| requirements of cars on the technicality that SUVs are
| "light truck" chassis[1]. Dan Luu shows that those safety
| regulations are often a box ticking exercise for
| manufacturers except Volvo[2]. American stroad design is
| a particularly bad mix of street and road which is more
| dangerous for drivers and pedestrians than other designs.
| And the diesel emissions scandal so many car
| manufacturers were caught defrauding.
|
| " _willingness to trade the safety of people for a
| cheaper X_ " is exactly what we should expect car
| companies (and companies in general) to do, because
| that's what they've done so often though history.
|
| [1] https://youtube.com/watch?v=jN7mSXMruEo "These stupid
| trucks are literally killing us" -NotJustBikes
|
| [2] https://danluu.com/car-safety/
| keep_reading wrote:
| https://www.enginelabs.com/engine-tech/engine/corrosion-
| of-c...
| alwayslikethis wrote:
| It is important to note that hydrogen, due to the small
| size of the molecule, is really hard to contain as a gas.
| Moreover, leaked hydrogen gas is an indirect but potent
| greenhouse gas via interfering with the degradation of
| existing methane in the atmosphere. If we leak enough
| hydrogen, we might not be helping the climate very much.
|
| I was once in a presentation which claimed formic acid to
| be a better alternative, but I'm not an expert in that
| field, so I can't comment on its merits.
| amluto wrote:
| There were some recent articles suggesting that there may
| be enough natural hydrogen seeping out of the ground to
| supply all of humanity's energy needs. It seems a bit
| unlikely that leakage of hydrogen from fuel systems would
| matter much in comparison.
| nick222226 wrote:
| How about radon, is that fissible?
| nukeman wrote:
| No, it gives off alpha particles and gamma rays.
| Hypothetically, you could build a device to harvest that
| energy (along the lines of an RTG), but the energy
| density and conversion efficiency would be laughable,
| given the 3.8 day half-life and gaseous state.
| ForgedEngine wrote:
| Use compressed air or NOx as oxidizers for delayed
| combustion in engines. Not only would it provide a means
| of storing energy for ICEs, but it would also eliminate
| pumping losses on the intake stroke.
| idontwantthis wrote:
| I wonder if this process would be easy enough that
| "ammonia battery" plants would just synthesize on site
| when solar power is high. Like charging up a battery with
| no need to move anything.
|
| Or maybe a regional factory with short pipelines.
| Retric wrote:
| At atmospheric pressure Ammonia liquifies at -28 degF
| (-33.3 degC), Hydrogen -423.17 degF (-252.87 degC). That
| alone is a vast improvement. You can build a
| car/boat/aircraft that keeps its Ammonia fuel tank cool
| with minimal effort however it's wildly impractical with
| hydrogen.
|
| Add the issues with hydrogen embrittlement and Ammonia
| starts to look trivial by comparison. People deal with
| industrial quantities of Ammonia on a regular basis without
| significant issues. Hell even gasoline and diesel are toxic
| and can be quite dangerous
| aifooh7Keew6xoo wrote:
| https://www.nbcchicago.com/news/local/attempt-to-pass-a-
| tank...
|
| No, they have significant issues on a regular basis
| still.
| Retric wrote:
| Anything dangerous at scale has issues. That doesn't mean
| people are unwilling to fill up at a gas station or use
| other hydrocarbon fuels despite plenty of far worse
| examples.
| https://www.npr.org/2021/11/06/1053162519/sierra-leone-
| oil-t...
|
| And plenty of more recent examples:
| https://www.fox29.com/news/tanker-truck-fire-closes-
| stretch-...
|
| Ammonia is one of the most common chemicals manufactured
| and transported around the world and has plenty of
| accidents but hydrocarbon accidents get into the hundreds
| of deaths: 150 dead
| https://en.wikipedia.org/wiki/Tacoa_disaster 500-600 dead
| 5000-7000 suffering severe burns
| https://en.wikipedia.org/wiki/San_Juanico_disaster 167
| dead https://en.wikipedia.org/wiki/Piper_Alpha
|
| People even hook up to natural gas lines after events big
| and small like: 300 dead
| https://en.wikipedia.org/wiki/New_London_School_explosion
| or here's a recent event which destroyed 60-100 homes htt
| ps://en.wikipedia.org/wiki/Merrimack_Valley_gas_explosion
| ...
| aifooh7Keew6xoo wrote:
| My primary point here is that if you see an ammonia spill
| you're going to die whether or not it explodes.
|
| I suppose it's worth noting in your second link, the
| fatalities were from the kinetics of the impact, which is
| a hazard that belongs to "things with velocity" rather
| than "things containing fuels".
|
| We can assume that uncontained fire and explosion are
| categorical hazards with fuels.
|
| Ammonia has significant risks that few other proposed
| fuels present and I believe it's worth considering
| whether this is something we want moving outside of
| hazmat routes between industrial zones.
| Retric wrote:
| Except the risk of fire / explosion is lower. NFPA 704
| for gasoline is 1 Health, 3 fire, 0 Instability where
| Ammonia is 3 Health, 1 fire, 0 Instability
|
| Major spills of either are dangerous but rare compared to
| how much is being created and transported. We're only ~5x
| as much gasoline vs Ammonia today. Considering most cars
| would be EV's I suspect the total amount of Ammonia
| produced even with widespread adoption isn't going to
| change by that much. Say Long haul trucks, heavy
| equipment, aircraft etc.
|
| PS: Which isn't to say Ammonia is actually a good fuel,
| the only thing I can think that actually used the stuff
| was the X-15. So it would need significant economic
| advantages to end up adopted.
| ianburrell wrote:
| You don't have to keep it cool. Ammonia has similar
| profile to propane. It is liquid at 7-14 bar. We build
| pressure tanks like that all the time for propane.
|
| Ammonia is probably too unsafe for cars and boats. But
| anything filled by professionals like trains or ships
| would work. But might work to have tank exchange system
| like with propane.
| LorenPechtel wrote:
| I was thinking about that but it's only a liquid at those
| pressures if you can keep it from getting too hot--say, a
| tank sitting there under the desert sun. And if your
| pressure relief triggers on ammonia it's a lot more of an
| issue than if it happens with propane.
| rossjudson wrote:
| Pretty sure they're talking about moving energy, not energy
| for moving.
| ClumsyPilot wrote:
| > danger to life and health at concentrations as low as 300
| ppm
|
| Well its not like you can put any petrochemical fuels in
| you coffee
| Gare wrote:
| This is for ammonia inhalation.
| lazide wrote:
| I don't think either is a good fit really, if that helps.
| doctorwho42 wrote:
| Replace highway infrastructure with train infrastructure
| that is powered by overhead lines. Build out the power grid
| to support that, and blanket the country with new rail
| lines that are nationalized and run as a public utility.
|
| Result, reduces carbon footprint of travel - land shipping
| - ability to build out modern towns - etc
|
| Toss in a bill to require all train lines to also install
| national fiber. You now have enabled the revitalization of
| large swaths of the county.
| andrepd wrote:
| Especially frustrating when considering that decarbonising
| a large part of transportation is easy, but boring: it's
| trains, light rail, it's cycling infrastructure. Not as
| sexy as futuristic energy sources, but it's what will save
| us in this sector: _viable alternatives to the horrendously
| inefficient automobile_
|
| This is not to mention everything else. The immense death
| toll directly (crashes) and indirectly (pollution,
| particulates, etc). The waste of space in cities. The waste
| of time in traffic that is unfixable if everyone is driving
| in an individual car. Etc etc. I wish people would stop
| trying to save the auto industry and start looking at the
| root of the problem.
| greggsy wrote:
| Bulk transport, not consumer vehicles
| cornholio wrote:
| The Haber Bosch reaction does not produce any CO2:
| N2 + 3H2 -> 2NH3
|
| The challenge is getting the zero emission Hydrogen. The
| process presented here is somewhat better than using
| electricity for the electrolysis split water, but still
| substantially more expensive than the gray Hydrogen obtain by
| cracking Methane gas and releasing the CO2.
| pfdietz wrote:
| Where did you conclude it was somewhat better than using
| electricity for electrolysis?
| PaulHoule wrote:
| The strangest thing is that Japan is thinking about burning
| ammonia together with coal
|
| https://about.bnef.com/blog/japans-ammonia-coal-co-firing-
| st...
|
| which I just can't imagine being clean when I consider that
| nitrogen oxides are also a concern with combustion fuels, not
| to mention it being an inefficient "battery" if you're making
| ammonia from green hydrogen and then burning it and spinning
| a turbine.
| conradev wrote:
| It's big enough and true enough for entrepreneurs - Nitricity
| is building shipping container-sized fertilizer factories
| aaron695 wrote:
| > Big if true...
|
| Could you explain exactly why you would say this?
|
| Working past their fake news headlines like 100%. Hydrogen is
| almost 100% and that's not big if true.
|
| We are decades away for renewable electricity only for our
| electric needs.
|
| Then you have oil and many other things electric can replace
| which are worse than gas.
|
| What about this is big? In a dream world of unlimited
| electricity everything is easy, like synth fuel and fertilizer
| and climate control. Today, burning coal to make fertilizer
| doesn't seem good, if this is true.
| colechristensen wrote:
| California produces about half of its electricity from
| renewables, mostly solar.
|
| We're decades away from 100%, but how long away are we
| nationally from 50%, 65%, 90%, 99%?
|
| As solar production ramps up to higher percentages there is
| going to be more and more peak power in excess of demand.
| Industrial scale electrochemistry is going to be one of the
| alternatives to batteries that's going to be developed.
|
| Already nitrogen fixation requires a huge amount of energy,
| this process at scale could very well require less energy
| than the modern haber process.
| applied_heat wrote:
| What factory that produces X is so cheap to build in
| relation to the cost of energy on a daily basis that it is
| worth producing less X at different times of day due to the
| price of energy? The cost of the energy is usually such a
| small component of total costs it is not worth altering
| behavior for daily small energy price fluctuations, and
| nobody is advocating for energy prices to change by 10x
| throughout the day.
| gofhwgwidi wrote:
| Aluminum
| colechristensen wrote:
| Before markets figured out how to take advantage, there
| have been several situations where electricity prices
| were regularly negative... they would pay for you to
| consume energy.
|
| When solar hits a certain ratio of production there will
| be a daily peak where electricity will be very cheap
| because there's too much of it, regardless of what people
| "advocate".
|
| Electrochemistry things are where it's at, metal refining
| specifically.
|
| Aluminum production from ore has one step where you
| literally just make what is effectively an enormous
| battery out of aluminum ore and "charge" it, when it's
| fully charged you've turned aluminum oxide into pure
| aluminum. It can even be run backwards to produce
| electricity because it's literally a battery (a really
| shitty one). So there's not a huge capital investment or
| complex process and electric input is actually a
| significant portion of the cost.
|
| Other simple electrochemistry things that do have a major
| portion of the cost in electricity can do the same when
| costs get low enough. There's a lot of recycling that
| becomes possible with cheap clean energy that you would
| never do with fossil fuel electricity.
| ianburrell wrote:
| We are decades away from needing this. But we need to
| generate ammonia without fossil fuels for fertilizer and feed
| stock.
|
| Also, we need a fuel for long distance transport like ships
| when batteries won't work. Ammonia will always be cheaper
| than synthetic fuel because no carbon doesn't have to come
| from air, and it stores better than hydrogen.
|
| There may be lots of surplus electricity in the future but
| there will also be a lot of demands for carbon capture,
| hydrogen, long term storage, and chemical processes.
| japanuspus wrote:
| At current costs, a price-optimal solar/wind/battery mix for
| handling existing electricity needs would have on the order
| of 400% overcapacity. All that extra electricity is what will
| power the hydrogen-generation.
|
| The main challenge is building cheap electrolysers without so
| much regard to efficiency, in order to use all the power when
| available. Most commercially available electrolysers today
| are expensive and cannot ramp up and down quickly.
| colechristensen wrote:
| CO2 production with current processes isn't necessary. They
| could use renewable electricity to hydrolyze water and power
| the plant, it's just cheaper to use the grid and methane as a
| source of hydrogen.
|
| Switching to carbon free ammonia would be no great task, just a
| price hike and some minor retrofitting.
| Paul-Craft wrote:
| Not until you can generate electricity at grid scale without
| CO2 emissions. That includes building the infrastructure to do
| so. Even nuclear doesn't get you there.
| scythe wrote:
| Oh it's true. But as the paper states, they produced 3.9
| millimoles -- 0.068 grams -- of ammonia in 96 hours.
|
| So I'm not exactly holding my breath. It's a big improvement
| over previous methods, but there's still a long way to go.
| hinkley wrote:
| Definitely hold your breath around people trying to produce
| ammonia.
| jojobas wrote:
| That's for a 1cm^2 electrode, as far as I remember not
| precious-metal rich either.
| thfuran wrote:
| So you only need an electrode about the size of Monaco to
| get 1 kg per second. Hopefully you can use some kind of
| foam or something.
| jojobas wrote:
| They sometimes use weird techniques to produce electrodes
| with specific area on the orders of thousands of square
| meters per gram. Even if it has to be flat, there's
| little holding you back from stacking 10k layers as long
| as you can manage the heat.
| HPsquared wrote:
| What does the term "current-to-ammonia efficiency" mean here? I
| imagine it would refer to the specificity of the reaction, i.e.
| that 99% of the electrons passing through the system are used in
| the main reaction, and <1% on side reactions.
|
| The abstract doesn't go into detail on energy efficiency and a
| comparison to the old method using gas. For instance, would this
| method result in less CO2 emissions using regular grid
| electricity, or would it need to be 100% low-carbon electricity?
| If, say, the electricity came from a CCGT plant, how would that
| compare? Etc etc
| tgsovlerkhgsel wrote:
| My naive interpretation would be "almost 100% of the energy put
| into the process gets chemically stored in the ammonia".
| adrian_b wrote:
| Not 100% of the energy, because even if no current is wasted,
| the voltage applied to the electrolysis cell is higher than
| the minimum value that corresponds to 100% energy efficiency.
|
| To know the energy efficiency, besides the current
| efficiency, which is close to 100%, we need to know how big
| is the overvoltage needed for electrolysis.
| cranky908canuck wrote:
| >> ... would this method result in less CO2 emissions using
| regular grid >> electricity, or would it need to be 100% low-
| carbon electricity? ...
|
| Who cares? This is about electricity to ammonia.
|
| Given: a very efficient way to make ammonia (as an energy
| store) using electricity, this becomes a storage mechanism. So
| then, make ammonia and money whenever the grid is in a 'pay to
| take power' state, and (up to a point) even if you have to pay.
| End source is irrelevant.
|
| Alternate process: run a solar farm, produce ammonia whenever
| that's cheaper than paying someone to take the power (or
| curtail), then sell the stored power when prices are high. Or,
| sell the ammonia directly.
| snewman wrote:
| Bear in mind that grid electricity is getting cleaner over
| time. We need to skate to where the puck is going, which is
| 100% clean electricity. Now is an excellent time to be
| developing and preparing to scale technologies that work well
| with clean electricity.
| HPsquared wrote:
| Yes - in theory, it's probably pretty efficient. Just would
| be interesting to see how it compares. We know it has good
| Coulombic efficiency, but that's only half the picture - at
| least for energy storage / synfuel applications.
| lambdatronics wrote:
| Probably refers to "Coulombic efficiency." Ie, it takes 4
| electron transfers to turn 2 H2 + N -> NH4, so that gives you a
| conversion factor between Coulombs of electrons (1 Amp of
| current is 1 Coulomb per second) and number of NH4 molecules
| produced.
|
| Yeah, someone would have to get access to the paper to see if
| they state the energy efficiency. I assume that b/c they don't
| mention it, it is abysmal. There's pressure to put good results
| into the abstract.
| hn_throwaway_99 wrote:
| This would be a _gigantic_ breakthrough if true and scalable,
| correct? Most ammonia production for fertilizer currently uses
| natural gas, and of clean sources of electricity with such a high
| yield of ammonia production would have a huge worldwide impact.
| So is there something I 'm missing?
| credit_guy wrote:
| The scalable part is going to be difficult though.
|
| This is not all that different from the production of hydrogen.
| Hydrogen is most economically produced from natural gas
| nowadays. You can produce it from water, with (just like here)
| an almost 100% current-to-hydrogen efficiency. But it's still
| twice as expensive, if not more.
| Superfluidity wrote:
| Electrolysis of water is 70-80% efficient (a 20-30%
| conversion loss) while steam reforming of natural gas has a
| thermal efficiency between 70 and 85%. https://en.m.wikipedia
| .org/wiki/Hydrogen_production#:~:text=....
| ororroro wrote:
| Current/Faraday efficiency is an entirely different thing.
| 100% current efficiency means you won't get a buildup of
| side products or erosion of your electrodes due to stray
| electrons. In isolation it is not a measure of power
| efficiency.
| hiddencost wrote:
| If you can start/stop the process easily, it could be a great
| sink for excess solar capacity.
| pfdietz wrote:
| Not if the energy efficiency were poor, compared to
| electrolytic hydrogen into a conventional Haber-Bosch process.
| And remember hydrogen is very storable, so that process could
| buffer renewable intermittency and keep the H-B plant running
| continuously. Electrolyzers are getting cheap.
| jillesvangurp wrote:
| Actually storing and transporting hydrogen are technical
| challenges. It takes up a lot of space and hydrogen molecules
| are so small they leak through a lot of materials. Not
| impossible but you need a lot of expensive infrastructure to
| handle it.
|
| Most hydrogen produced today is consumed very close to where
| it is produced. Also energy storage and fuel type use cases
| rank very low on Michael Liebreich's hydrogen ladder. That's
| a nice tool that ranks different uses of hydrogen by their
| economic feasibility and overhead. Chemically binding it to
| something else to store it works of course. Ammonia (NH3) is
| common for this; and in fact the biggest use case for
| hydrogen. People have speculated about using that as a fuel.
| It's much easier to store and transport. And of course these
| chemical transformations also have an energy cost.
| pfdietz wrote:
| Actually, storage and transportation are positives for
| hydrogen. It's easier to transport and store hydrogen than
| it is to transport and store electricity. Hydrogen can be
| stored underground in caverns very cheaply (this is a
| demonstrated technology already in use for buffering
| hydrogen produced from fossil fuels), compared to the cost
| of equipment for storing electrical energy. Hydrogen is a
| viable for seasonal storage of renewable energy, unlike
| batteries.
|
| The negative for hydrogen is poor round trip efficiency of
| electricity -> hydrogen -> electricity. But for
| sufficiently long storage times the lower cost of storage
| capacity vs. batteries overwhelms that, and hydrogen
| becomes cheaper for grid storage.
| lambdatronics wrote:
| Probably not just yet. I calculated downthread that the
| productivity is something like 16x less per unit area than a
| hydrogen electrolyzer, so that would need to be improved to
| make it cost-effective probably. Also they don't mention the
| energy efficiency, only the "current efficiency" so I would
| assume the energy efficiency is also poor. Sounds like there's
| much to be done still.
| DarkmSparks wrote:
| Nice. Think it was Toyota recently got themselves an ammonia
| combustion engine prototype running as well.
| tgsovlerkhgsel wrote:
| One downside of ammonia is its toxicity (with an IDLH threshold
| of 300 ppm). I doubt we'll ever see cars running on it, and
| storing large amounts as energy storage sounds risky.
|
| Do we know if this process is burstable (i.e. the devices for
| running it are likely cheap enough compared to the energy
| requirement that they don't need to run 24/7, and could use
| excess renewable energy when available)?
| ilyt wrote:
| Well, petrol or diesel isn't that nice either
| lazide wrote:
| Anhydrous ammonia is much worse, creating rolling clouds of
| ground level deadly gas for long distances. And being very
| flammable. And explosive.
|
| Gas doing 2 of those 3, and diesel only 1.
| fbdab103 wrote:
| If it is cheap, that will beat out a lot of other concerns.
| Not sufficient for consumer use, but power plants are
| already hazardous places that can engineer significant
| safety controls.
| TheSpiceIsLife wrote:
| Diesel is none of those things.
|
| I have extinguished a fire with diesel.
| lazide wrote:
| Diesel is definitely flammable. I works great as an
| accelerant.
|
| It isn't as easily flammable as gas, and doesn't have
| easily autoignitable vapor like gas.
|
| I'm guessing you dumped a lot of it on something without
| a lot of thermal mass?
|
| If you did the same on a bonfire, you'd have a different
| story.
| im3w1l wrote:
| Could we use this process as a building block in the
| synthesis of some "nicer" fuel? What can ammonia be semi-
| efficiently converted to?
|
| Edit: Maybe methanol?
| jacoblambda wrote:
| Well... there's hydrazine (N2H4) which is the stuff they
| use as monopropellant rocket fuel. It burns even without
| the presence of oxygen and it's even more toxic and
| explosive than ammonia. It's the reason the capture crews
| for returning spacecrafts wear hazmat suits.
|
| However hydrazine is liquid at room temperature and it
| can be converted to hydrazone (also being considered for
| fuel cells) which is solid at room temperature and non-
| reactive... until it comes into contact with water at
| which point it all turns back into hydrazine.
|
| But yeah no there's really not a "nicer" fuel. Generally,
| if it has nitrogen in it and it isn't literally just
| nitrogen with itself, it's dangerous. And the more
| nitrogens it has the more dangerous it is.
| lazide wrote:
| If there is anything that would make ammonia seem warm
| and cuddly, it is indeed hydrazine!
|
| Urea maybe? It's almost non toxic and is 2x ammonia + a
| carbon monoxide molecule.
|
| though not sure how efficient it would be to extract
| energy from.
|
| Speaking of 'extra nitrogen's are generally bad', a
| callout to the azides!
|
| https://en.m.wikipedia.org/wiki/Azide
|
| https://en.m.wikipedia.org/wiki/Lead(II)_azide
| gimmeThaBeet wrote:
| I agree, it's kind of a different class of threat for
| everyday people.
|
| Not assuming it would be the same, but picturing a spill at
| a gas station. Spilling gas is a problem, but at least it's
| just sort of _there_. If you get an ammonia leak and it
| forms a vapor cloud, I don 't think most people would know
| how to deal with that. I'll bet your spilled gas likely
| won't migrate into the intersection.
|
| But on the plus side, we already see what
| handling/transportation of large amounts looks like for
| agriculture, even if rail carriers etc. dislike dealing
| with it.
| lazide wrote:
| For sure - definitely doable, and certainly not the worst
| industrial chemical used at large scale. But not super
| consumer friendly.
| alwayslikethis wrote:
| Correction: Ammonia is not flammable since the flash point
| is significantly above room temperature. It would only be
| explosive if you consider the pressure vessel exploding,
| but we also have natural gas powered cars which also have
| pressurized cylinders. The main real issue is the toxicity.
| bluGill wrote:
| Who cares of it explodes, just breathing the stuff is
| deadly.
| lazide wrote:
| Nope. Anhydrous ammonia between 18-25% is literally
| 'explodes like gas vapor' type explosive/flammable.
|
| [https://www.worksafebc.com/en/resources/health-
| safety/risk-a....] [https://www.osha.gov/laws-
| regs/standardinterpretations/1994-....]
|
| It does have a higher ignition point than gas. But one a
| spark can definitely reach. It's been a common problem in
| industry where ammonia gets used a lot (refrigeration in
| particular).
|
| BLEVE's are also a problem too of course. And the toxic
| nature of breathing it in! Haha.
| totetsu wrote:
| Wasn't that what happened on the docks in Beirut? Or were
| their fireworks stored next to it that time
| lazide wrote:
| Different (but related) chemical. That was ammonium
| nitrate (fertilizer + blasting agent). Which ammonia is
| used to make at large scale.
| zeristor wrote:
| Looking at the paper, in similar papers reference is made to this
| paper published 13th September 2023:
|
| "Laser-induced nitrogen fixation"
| https://www.nature.com/articles/s41467-023-41441-0
|
| This is Open Access, and mentions how that is also a leap forward
| in Nitrogen fixation
|
| "Abstract: For decarbonization of ammonia production in industry,
| alternative methods by exploiting renewable energy sources have
| recently been explored. Nonetheless, they still lack yield and
| efficiency to be industrially relevant. Here, we demonstrate an
| advanced approach of nitrogen fixation to synthesize ammonia at
| ambient conditions via laser-induced multiphoton dissociation of
| lithium oxide. Lithium oxide is dissociated under non-equilibrium
| multiphoton absorption and high temperatures under focused
| infrared light, and the generated zero-valent metal spontaneously
| fixes nitrogen and forms a lithium nitride, which upon subsequent
| hydrolysis generates ammonia. The highest ammonia yield rate of
| 30.9 micromoles per second per square centimeter is achieved at
| 25 degC and 1.0 bar nitrogen. This is two orders of magnitude
| higher than state-of-the-art ammonia synthesis at ambient
| conditions. The focused infrared light here is produced by a
| commercial simple CO2 laser, serving as a demonstration of
| potentially solar pumped lasers for nitrogen fixation and other
| high excitation chemistry. We anticipate such laser-involved
| technology will bring unprecedented opportunities to realize not
| only local ammonia production but also other new chemistries."
| wolfi1 wrote:
| "The corresponding lowest energy consumption of ammonia
| synthesis based on the light power can be calculated to be
| approximately 322 kWh kg-1 NH3 (Fig. 3b). This value is
| significantly higher than that (10 to 13 kWh kg-1 NH3) of the
| H-B process at an industrial scale" still way to go. found
| nothing about the "subsequent hydrolysis" step, skimming the
| article
| nullc wrote:
| > (10 to 13 kWh kg-1 NH3) of the H-B process at an industrial
| scale"
|
| It isn't clear to me how they're pricing the H-B process
| there, industrial HB uses hydrogen from hydrocarbons. An
| apples to apples comparison would at least add the energy you
| could get from burning the hydrogen instead, but arguably
| should compare with H-B where the hydrogen comes from
| electrolysis of water.
|
| > "subsequent hydrolysis"
|
| As far as I can tell, you just add water. zap rinse repeat.
| I'm a little skeptical that their yield figures were for Li2O
| though the repeated process has you cycling through LiOH
| after the first pass.
| pfdietz wrote:
| Yeah, that's grossly too inefficient. This is nothing more
| than a lab curiosity.
| NotYourLawyer wrote:
| If it uses a laser, it wastes a lot of energy.
| shrubble wrote:
| Interesting paper from 2019 if you are thinking about burning
| ammonia for e.g. power plants etc.
| https://www.sciencedirect.com/science/article/pii/S154074891...
| rational_indian wrote:
| >150 +- 20 nmol s-1 cm-2
|
| Isn't this miniscule? Is this commercially viable?
|
| Edit: The molecular mass of nitrogen is 28, so 1 mol is 28 grams,
| so 150 nmol is 28 x150 nano grams = 4.2 micro grams. How much gas
| is this?
| oldbbsnickname wrote:
| Incorrect in multiple respects. The molar mass of N is
| 14.006747 g/mol, while ammonia is 17.03052 g/mol. Gas expands
| to fill the container, so it's only worth discussing in mass
| terms.
|
| It's rate of production over the area of the catalyst. Put
| another way, that's 1.5 +- 0.2 mmol/m2s or 25.5 +- 3.4 mg/m2s.
|
| 24 hours of production over a catalyst with an area of 1000 m2
| would create 25 +- 3.4 t. That's about the product weight of a
| typical full cold / cool towed trailer tank sent to large-scale
| customers. A commercial ammonia refinery would need many
| multiples of this area to be economically viable.
|
| https://alliancetruckandtank.com/products/transport-trailers...
| gpm wrote:
| Any idea how tightly can these cells likely be packed in 3d?
| Is 1000 m2 likely to be 1 m3 or 1000 m3?
| lambdatronics wrote:
| For hydrogen electrolysis they typically quote around 1 A/cm^2
| current. One Coulomb is ~6e18 charges, whereas one mole is 6e23
| molecules, so that makes about 1e-5 H atoms per cm per second.
| Of course making one molecule of ammonia needs 4 H atoms, so it
| works out to something like 16x lower productivity. I assume
| it's not competitive as is.
| keep_reading wrote:
| Toyota has an engine that runs on ammonia
|
| https://www.enginelabs.com/engine-tech/engine/corrosion-of-c...
| anon_cow1111 wrote:
| I need to ask this question for any chemical engineers currently
| reading this. I'm seeing people in the comments talking about how
| this could be applied to consumer vehicles, not just industry
| like cargo ships and agriculture.
|
| If I, the consumer, had unlimited access to cheap, unregulated
| liquid ammonia (as common as gasoline), how many precursor-steps
| am I away from having access to like... a LOT of high explosives?
|
| -asking for your friendly neighborhood crazy person with a
| vendetta against... whoever.
|
| As far as I can see, it's a very similar problem to hydrogen. It
| doesn't matter how safe you can make it, it matters how dangerous
| a random nutjob can make it.
| sidewndr46 wrote:
| What would it matter? I can go buy as much materials to make
| explosives as I want today.
|
| Or I could just purchase actual explosives at the sporting good
| store, like tannerite.
| anon_cow1111 wrote:
| Yes, the difference is tannerite (by yield) is many times
| more expensive, and much easier to trace when someone buys
| hundreds of pounds of it from a sporting goods store.
| Similarly, a random individual buying a half ton of AN would
| probably trip some kind of alarm bells somewhere.
| sidewndr46 wrote:
| half ton? If I was headed to a friend's house who owns a
| farm and they asked me to pick up half a ton of farm
| supplies I would think nothing of it. Even my truck with
| its tiny payload can carry that around
| mcpackieh wrote:
| If somebody asks you to buy half a ton of fertilizer on
| their behalf, I suggest you think twice about it. Why do
| they want you to buy it for them? Even if he's a farmer,
| with a rational use for that much fertilizer, why is he
| making such an unusual arrangement to receive fertilizer
| through his friend instead of buying it himself normally?
|
| Who knows man, maybe feds caught him with some pot plants
| and now he's setting you up in some sort of bullshit
| anti-terror sting to cut a deal. Regardless of what kind
| of truck you have, casually buying half a ton of
| fertilizer for somebody else is an odd request that
| warrants some explaining.
| seventytwo wrote:
| It only needs to be as safe as fossil fuels, or even slightly
| less safe, if the benefits are higher.
|
| This always bothers me. People freak out about LiIon battery
| failures, or hydrogen, or ammonia, or nuclear power. But here
| we are with an entire economy riding on an explosive, firey,
| dirty fuel that is already causing global climate problems.
|
| Safety concerns should be kept on-par with what we have today.
| Let's not throw out a good solution because it can be dangerous
| in some cases. Any high-energy-dense thing we switch to after
| fossil fuels is going to release that energy if handled
| improperly. That concern should be quite low on the list.
| lazide wrote:
| Fueling up with ammonia is roughly as dangerous as fueling up
| with concentrated pesticide, on the health risk scale. It's
| _much_ more toxic than gasoline.
|
| And also flammable/explosive.
| vGPU wrote:
| You can buy ammonium nitrate in bulk. Much easier to turn into
| an explosive if that's the point you're making. Just say you're
| opening a farm and off you go.
| anon_cow1111 wrote:
| Well of course, but that only works _once_ before you get
| traced and caught, might still be acceptable for the
| aforementioned crazy guy but I assume most others would
| rather blend in with the 50 million people buying gas on any
| given day.
| lazide wrote:
| Anhydrous ammonia is even more illegal in most places to
| get - apparently it's a precursor to meth production or
| something?
| anon_cow1111 wrote:
| I heard something about this too, though I omitted it for
| the sake of brevity. Don't know the specifics, but yes I
| think it's also a drug precursor. I remember some CCTV
| footage of people stealing ammonia from large tanks on a
| farm, not sure what other reason they would have other
| than drug production.
| Horffupolde wrote:
| Not a reasonable path.
| jandrewrogers wrote:
| Synthesizing high explosives from anhydrous ammonia is not
| trivial and no random person would ever bother. There are
| easier precursors to work with and much easier ways to acquire
| high explosives than trying to bootstrap from ammonia.
|
| And if someone really was bent on mayhem, well, anhydrous
| ammonia is nasty toxic stuff as is. You don't need to do
| anything chemically to it to kill or injure a lot of people. On
| the other hand, it isn't a chemical that sneaks up on you. If
| you are being exposed to dangerous levels, you'll know it.
| fodkodrasz wrote:
| It is already very dangerous, no need to turn it into an
| explosive. It won't be given out for handling to untrained
| people.
| eternauta3k wrote:
| From https://en.wikipedia.org/wiki/Haber_process#Process:
|
| > ammonia production is energy-intensive, accounting for 1% to 2%
| of global energy consumption, 3% of global carbon emissions,[23]
| and 3% to 5% of natural gas consumption
|
| Big if we can improve this.
|
| For more on the Haber process and its impact on the world, I
| highly recommend this book: "The Alchemy of Air: A Jewish Genius,
| a Doomed Tycoon, and the Scientific Discovery That Fed the World
| but Fueled the Rise of Hitler" by Thomas Hager.
| danans wrote:
| This could be a game changer for seasonal energy storage if it
| allows round trip efficiencies of even say 60%. Ammonia has been
| demonstrated as a fuel in existing natural gas turbines [1] at
| combustion efficiencies up to 99%.
|
| 1. https://nh3fuelassociation.org/2018/12/07/performance-of-
| amm....
| hinkley wrote:
| Highly caustic to delicate tissues however, such as lung
| tissue.
| danans wrote:
| Undoubtedly, at the scales needed for seasonal energy
| storage, containment systems with multiple fail-safes would
| be needed. But if we can do that for nuclear reactors, it's
| got to be strictly simpler for ammonia.
| hinkley wrote:
| Some early fridges ran on ammonia as the refrigerant.
| Didn't survive scaling up to mass production. Neither has
| nuclear.
| lambdatronics wrote:
| First you want to displace natural gas for fertilizer
| production. But yes, if the energy efficiency is good enough
| and the electrolyzer costs are very low, it would make more
| sense than electrolyzing hydrogen and then running that through
| Haber-Bosch. Remains to be seen if either of those criteria can
| be met.
| lambdatronics wrote:
| The paper says that this is only _half_ of a solution: "Our
| investigation here has focussed [sic] on the fundamental Li-NRR
| performance at the cathode. Further developments towards a
| complete ammonia electrosynthesis system will require
| investigations of appropriate anode reactions while eliminating
| sacrificial solvent oxidation. A feasible initial strategy is to
| couple the Li-NRR with the H2 oxidation reaction, which has
| already been demonstrated but requires improvements in stability
| and activity. A more-desirable anode process is H2O oxidation,
| which presents larger challenges because of the potential
| interference of water with the Li-mediated process and vice
| versa."
|
| This system involves ethanol as a sacrificial hydrogen donor:
| "The amount of ammonia produced in the 96 h experiments (3.9 +-
| 0.1 mmol) was around four times higher than the amount of ethanol
| present (1 mmol), indicating that it is not a completely
| sacrificial reactant but can also operate as a proton carrier."
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