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Wikipedia:Reference desk/Archives/Science/2021 December 8

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December 8

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CiteSeerX and DOI

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CiteSeerX and DOI:

what the heck ?
.... 0mtwb9gd5wx (talk) 01:44, 8 December 2021 (UTC)[reply]
That's not a properly formatted DOI. DOIs should take the form of "10.1000/xyz123," but there is no forward slash in the DOI you've given. --OuroborosCobra (talk) 02:08, 8 December 2021 (UTC)[reply]

Can ammonia be used instead of natural gas in gas stoves and home heating systems?

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Ammonia can be produced from hydrogen, it's easier to transport and store than hydrogen itself. However, can ammonia then be directly combusted in the systems that are designed to combust natural gas? Count Iblis (talk) 07:39, 8 December 2021 (UTC)[reply]

First, natural gas isn't just hydrogen. People don't burn hydrogen gas in gas stoves. Also, natural gas doesn't have to be produced, just extracted. Clarityfiend (talk) 09:21, 8 December 2021 (UTC)[reply]
As implied below, natural gas is not even mostly hydrogen, but rather methane, see for instance that source. Article improvement suggestion: put typical compositions somewhere in the article natural gas. TigraanClick here for my talk page ("private" contact) 16:00, 8 December 2021 (UTC)[reply]
AFAICT there's nothing in the OP's question suggesting natural gas contains significant amounts of hydrogen. Instead the OP seems to be asking whether ammonia produced from hydrogen, probably blue, turquoise or green hydrogen, can be used as a direct substitute for natural gas perhaps aware that hydrogen can not be or maybe they consider it unimportant since the main issue is whether hydrogen converted to ammonia for reasons of transport, storage etc can be used as a direct natural gas substitute (since if it can then whether hydrogen can be might be irrelevant if ammonia is overall a better option). The ultimately goal we can assume is likely to come up with a more climate friendly substitute for natural gas hence why the hydrogen being considered here would likely be blue, turquoise or green. Nil Einne (talk) 02:49, 9 December 2021 (UTC)[reply]
I agree. Must be old age creeping up on me. Clarityfiend (talk) 05:00, 9 December 2021 (UTC)[reply]
Per our article on the Haber process, a significant fraction of the world's energy (article says 1% to 2%) goes into reacting hydrogen with nitrogen to make ammonia. It would be pretty odd, I think, to do that just to burn the ammonia, especially from a "green" point of view (not sure what "blue" and "turquoise" refer to here). --Trovatore (talk) 03:30, 9 December 2021 (UTC)[reply]
See [1] for discussion of the various "colors" of hydrogen. DMacks (talk) 06:07, 9 December 2021 (UTC)[reply]

Odd perhaps but seems to be under active consideration. Well not in the form the OP suggests but Japan in particular (and to a much lesser extent South Korea) seems to have a lot of interest in using ammonia to supplement and eventually replace coal in their power stations [2] [3] [4] [5] [6]. (The last link also has discussion about the colours BTW.)

Besides using ammonia directly in power stations, there is also a suggestion it could be used for transportation, either directly with ammonia fuel cells [7], but more likely indirectly i.e. being used to make hydrogen. [8]

If using hydrogen to make ammonia to use as a fuel sounds silly, using hydrogen to make ammonia to make hydrogen seems even sillier. But as the Science news article says the problem is that transporting and storing hydrogen in bulk effectively is still something we don't have good solutions for. But transporting and storing ammonia in bulk is something we have a lot of experience with and a lot of existing facilities for. The Science article claims currently (well in 2018 I guess), the energy loss from the roundtrip conversion is similar to liquifying hydrogen. So it seems some have decided ammonia as an intermediary is the best solution.

Beyond Japan apparently deciding to go big on hydrogen and ammonia although this isn't directly stated in any source I've read so is OR, I suspect another reason why this is recently such a big thing is precisely because of what we're already doing. I suspect those investing in it in from Japan etc figure that even if it completely fails as a fuel, low carbon ammonia is of interest due to the need to fill the world's existing demand for ammonia mostly for fertiliser. So if they can "crack" (pun not really intended) the market for low carbon ammonia, they'll still be successful even if it never becomes a fuel. And likewise there's also interest, investment, research etc from those who think the idea of using is as a fuel is odd but are looking for a solution for our existing demand. Interesting enough although only relevant in a very limited way, there's recently been a lot of noise about a shortage of urea [9] [10]

Nil Einne (talk) 10:27, 10 December 2021 (UTC)[reply]

To be clear, I'm not saying Japan's plans make sense. As the BBC article says it sort of seems like they're stuck in a sunk cost situation. Fukushima meant they made a lot of new coal power stations at a time when most of the developed world was starting to turn off them. But this happened just around the time renewables were starting to be cost effective. Now they're trying to find a way to keep them going since they don't want to decommission power plants they just built. Nil Einne (talk) 10:44, 10 December 2021 (UTC)[reply]
At the very least you have to adjust the device to change the fuel to air ratio. Ammonia reacts with oxygen in a 4:3 ratio, methane in a 1:2 ratio (and hydrogen in a 2:1 ratio). You even have to adjust a British gas stove when moving it to the Netherlands, as the composition of the natural gas is different. But a bigger problem is that ammonia is rather toxic. 300 ppm is the limit of what's considered immediate danger. For methane, the main danger is getting an explosive mixture with air at about 50000 ppm, so an ammonia leak is far more dangerous than a methane leak. PiusImpavidus (talk) 09:28, 8 December 2021 (UTC)[reply]
You can read this article. Ruslik_Zero 20:15, 8 December 2021 (UTC)[reply]
When ammonia is burnt it is much more likely to produce nitrogen oxides, which is not generally a good idea for pollution or climate reasons. If using blue hydrogen, you may as well have just burnt the methane. Or for fuel transform the methane into bigger hydrocarbons. Graeme Bartlett (talk) 21:58, 9 December 2021 (UTC)[reply]
Yes you can, but ammonia is pretty nasty stuff. If given the choice, for most uses, I'd reformulate the H2 from pV electrolysis into methane, a fuel we are used to handling and that is somewhat less obnoxious. The obvious use for ammonia is fertiliser. Greglocock (talk) 23:48, 9 December 2021 (UTC)[reply]
To echo others, ammonia is poisonous. It may be technically feasible, but probably not a very wise idea. Ammonia is in wide use industrially as a refrigerant, and places that use it need leak detection systems, evacuation procedures, hazardous materials training for people on-site, you get the picture. Natural gas is not toxic, merely flammable and a possible asphyxiant in confined spaces—as is any gas not oxygen. All the work that would be required to do such a thing might as well be invested in replacing natural gas appliances with electric ones. --47.155.96.47 (talk) 08:07, 10 December 2021 (UTC)[reply]
"Places that use it need leak detection..." On the other hand, many, if not most, RV refrigerators are ammonia systems, and have no special leak detection or other such things. --jpgordon𝄢𝄆𝄐𝄇 15:27, 11 December 2021 (UTC)[reply]
Correct. These are absorption refrigerators (explicit link for readers). But the amount of ammonia is limited to what's contained in the fridge's refrigerant loop. Converting a natural gas distribution system to distribute ammonia would produce the possibility of large, dangerous ammonia leaks. --47.155.96.47 (talk) 11:16, 12 December 2021 (UTC)[reply]

Bug species

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Could someone identify this bug or beetle species, please? Length is slightly less than half of the index finger, sitting calmly in a living room in Poland. 212.180.235.46 (talk) 12:54, 8 December 2021 (UTC)[reply]

It's a shield bug, but not sure which one. Mikenorton (talk) 13:22, 8 December 2021 (UTC)[reply]
It could be a Brown marmorated stink bug, which has been reported from Poland. Mikenorton (talk) 13:28, 8 December 2021 (UTC)[reply]
Thanks all. 212.180.235.46 (talk) 18:07, 8 December 2021 (UTC)[reply]
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