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

nature.com

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

#161

Post by ForgedEngine »

lazide wrote: post #78
alwayslikethis wrote: post #66

Earlier quoted context omitted.

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.

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 partic…

The flash point is well above any ambient temperature it would be stored at.

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

#162

Post by lazide »

ForgedEngine wrote: post #161
lazide wrote: post #78

Earlier quoted context omitted.

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 partic…

The flash point is well above any ambient temperature it would be stored at.

Your point is?

Gasoline fumes don’t typically auto-ignite either. And that is all flash point is about.

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

#163

Post by applied_heat »

gofhwgwidi wrote: post #117
applied_heat wrote: post #92

Earlier quoted context omitted.

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.

Aluminum

Do aluminum factories shut down daily due to fluctuating prices or are they located in areas with cheap and plentiful reliable electricity supply?

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

#164

Post by cornholio »

pfdietz wrote: post #142
cornholio wrote: post #129

Earlier quoted context omitted.

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.

Where did you conclude it was somewhat better than using electricity for electrolysis?

I took the author's claim of 100% electrolytic efficiency at face value and contrasted with typical water electrolysis efficiencies, followed by a Haber-Bosch step.

This method of direct electroreduction should not confused with the Laser-induced method discussed elsewhere in the thread, which has abysmal numbers.

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

#165

Post by NotYourLawyer »

notsure2 wrote: post #158
NotYourLawyer wrote: post #138

Earlier quoted context omitted.

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

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

There’s that, but I meant just turning electrical energy into photons. Diode lasers are pretty decent at 50ish percent efficient. Everything else is way, way worse.

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

#166

Post by sfink »

amluto wrote: post #89
sfink wrote: post #53

Earlier quoted context omitted.

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.

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 student…

My dad did this once. He drained the acid from a car battery and put it in a container with a narrow opening, then dropped in a bunch of zinc galvanized nails. Sulfuric acid + zinc = hydrogen gas. He then stretched balloons over the mouth of the container to inflate them, tied them up, and attached a strip of newspaper to the bottom. Finally, he lit the bottom of the newspaper on fire and let it go. Balloon floats up, makes pretty fireball.

We ran into two problems. First, a number of the flames blew out on their way up. No fireball.

Second, we ran out of balloons pretty fast. So he cast around for ideas, and decided to fall back on a box of condoms. They held a lot more hydrogen than the balloons.

They were also equally likely to go out before blowing up. I always imagined them coming down on someone's lawn, causing no end of confusion.

[DO NOT TRY THIS AT HOME! And if you're tempted, there's one thing I left out that's necessary for it to work properly, and the only thing I'll say about it is this warning: https://sciencenotes.org/add-acid-to-water-or-water-to-acid/ ]

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

#167

Post by amluto »

sfink wrote: post #166
amluto wrote: post #89

Earlier quoted context omitted.

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 student…

My dad did this once. He drained the acid from a car battery and put it in a container with a narrow opening, then dropped in a bunch of zinc galvanized nails. Sulfuric acid + zinc = hydrogen gas. He then stretched balloons over the mouth of the container to inflate them, tied them up, and attached a strip of newspaper to the bottom. Finally, he lit the bottom of the newspaper on fire and let it go. Balloon floats up…

That’s not the same thing, though — your dad forgot the oxygen! A balloon full of approximately pure hydrogen makes a nice fireball but doesn’t really explode — the same group that made the exploding balloon I watched also did one of those.

The stoichiometric premixed balloon is only 2/3 H2 by volume, so it releases 1/3 less energy, but it’s a whole different experience when the energy is released essentially all at once. Interestingly, there was no noticeable fireball from the premixed balloon.

A premixed H2+air balloon probably makes a fine explosion, too :)

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

#168

Post by amluto »

nick222226 wrote: post #98
amluto wrote: post #82

Earlier quoted context omitted.

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.

How about radon, is that fissible?

To be clear, I’m saying enough hydrogen to power humanity chemically, not by fusion.

Enough hydrogen to power humanity by fusion is readily available anywhere :)

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

#169

Post by sfink »

amluto wrote: post #167
sfink wrote: post #166

Earlier quoted context omitted.

My dad did this once. He drained the acid from a car battery and put it in a container with a narrow opening, then dropped in a bunch of zinc galvanized nails. Sulfuric acid + zinc = hydrogen gas. He then stretched balloons over the mouth of the container to inflate them, tied them up, and attached a strip of newspaper to the bottom. Finally, he lit the bottom of the newspaper on fire and let it go. Balloon floats up…

That’s not the same thing, though — your dad forgot the oxygen! A balloon full of approximately pure hydrogen makes a nice fireball but doesn’t really explode — the same group that made the exploding balloon I watched also did one of those. The stoichiometric premixed balloon is only 2/3 H2 by volume, so it releases 1/3 less energy, but it’s a whole different experience when the energy is released essentially all at…

> That’s not the same thing, though — your dad forgot the oxygen!

Oh, I'm quite aware. The other fun game we played was with his acetylene welding torch and balloons. It has separately controlled tanks of acetylene and oxygen. Acetylene only = nice big fireball. Acetylene + oxygen = no fireball at all, instead a very loud boom + a bit of a shockwave.

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

#170

Post by ForgedEngine »

lazide wrote: post #162
ForgedEngine wrote: post #161

Earlier quoted context omitted.

The flash point is well above any ambient temperature it would be stored at.

Your point is? Gasoline fumes don’t typically auto-ignite either. And that is all flash point is about.

No, autoignition and flash point are two completely different things.
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