Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022) • Hacker News Board

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#151

Post by Terr_ » Sun, Oct 29, 2023, 7:41 PM UTC

toomuchtodo wrote: post #36

Terr_ wrote: post #32

Earlier quoted context omitted.

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.)

High efficiency scrubbing appears to be feasible. https://pubs.acs.org/doi/10.1021/acs.energyfuels.3c01419

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#152

Post by colechristensen » Sun, Oct 29, 2023, 8:19 PM UTC

applied_heat wrote: post #92

colechristensen wrote: post #54

Earlier quoted context omitted.

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 nitrog…

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.

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#153

Post by lambdatronics » Sun, Oct 29, 2023, 8:38 PM UTC

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."

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#154

Post by aifooh7Keew6xoo » Sun, Oct 29, 2023, 9:39 PM UTC

thfuran wrote: post #135

aifooh7Keew6xoo wrote: post #39

Earlier quoted context omitted.

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…

But hydrogen likes to make invisible fires and leak through solid steel, and it needs to be ludicrously cold to liquify.

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#155

Post by PaulHoule » Sun, Oct 29, 2023, 9:49 PM UTC

RetroTechie wrote: post #7

londons_explore wrote: post #2

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.

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 i…

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#156

Post by jojobas » Sun, Oct 29, 2023, 9:51 PM UTC

thfuran wrote: post #136

jojobas wrote: post #132

Earlier quoted context omitted.

That's for a 1cm^2 electrode, as far as I remember not precious-metal rich either.

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.

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#157

Post by LorenPechtel » Sun, Oct 29, 2023, 10:09 PM UTC

ianburrell wrote: post #72

Retric wrote: post #41

Earlier quoted context omitted.

At atmospheric pressure Ammonia liquifies at −28 °F (−33.3 °C), Hydrogen −423.17 °F (−252.87 °C). 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 r…

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.

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.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#158

Post by notsure2 » Mon, Oct 30, 2023, 12:31 AM UTC

NotYourLawyer wrote: post #138

zeristor wrote: post #27

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 e…

If it uses a laser, it wastes a lot of energy.

How so? photons that don't participate in the reaction?

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#159

Post by ForgedEngine » Mon, Oct 30, 2023, 1:03 AM UTC

Terr_ wrote: post #32

toomuchtodo wrote: post #19

Earlier quoted context omitted.

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.am…

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.)

NOxs are practically zero with HCCI at a stoichiometric ratio.

Re: Nitrogen electroreduction with almost 100% current-to-ammonia efficiency (2022)

#160

Post by ForgedEngine » Mon, Oct 30, 2023, 1:09 AM UTC

dexwiz wrote: post #15

fbdab103 wrote: post #8

Earlier quoted context omitted.

Are there power plants today that burn ammonia directly? If not, is it a simple/cheap enough conversion?

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.

Filter the exhaust through a caustic solution to neutralize NOxs.