Hydrocarbons are energy dense and convenient. I recall some noise about ammonia being energy dense and convenient also, but having the touted benefit of not emitting carbon dioxide or something similar.
What are the drawbacks to shifting to ammonia as a widespread fuel for IC engines?
I am not a smart man, so please answer in words suitable for a toddler, or even better, an art student with enthusiasm towards windmills.
Thanks in advance.
There isn't a simple answer because it depends on the detail, but in round numbers Ammonia only gives half the energy per kilo of fuel as hydrocarbons. That's because a lot of the weight is there in nitrogen, which doesn't really burn (and you don't want to be producing oxides of nitrogen anyway).
Ah, I see. Thank you very much.
NH3 Anhydrous ammonia fuel needs refrigeration and/or pressure to remain a liquid. Corrosive and poisonous are its two main drawbacks...
Burning it invariably produces some nitric oxides (no surprise there).
Widely used in industry at one time for large scale ice making plants. You could smell the leaks a mile off (and it usually did).
The only thing in its favour is it isn't as nasty as hydrazine N2H4.
I thought it was relatively non-energy dense?, I've heard of it possibly being suited for ships, instead of bunker fuel.
I posted this in another thread:
Interesting idea. Mostly the problem would be its likely to emit instead of nitrogen and water, a lot of nitrogen oxides...and it doesn't burn in just air easily.
Could be done though.
It is often touted as a way of converting green hydrogen into a fuel that is more easy to handle. There is a fair bit of interest in it for shipping applications where batteries won't hack it. It does not burn as cleanly, and the extra manufacturing steps add more inefficiencies to the process.
Great stuff!
Yeah, that's terrible.
Always an upside!
Thank you!
In a shocking revelation, I don't really know why nitrogen oxides are bad. I know that the wrong NOx number at MOT time will make you miserable though.
Am I right to assume that nitrogen oxides are what lead to acid rain? Or is that sulphurous compounds? Or both?
Thank you.
Jeeze no, nothing so nasty! I recall a demo in front of the class, and I think the teacher was able to put is hand into the flame. But I think my memory must be faulty as I can't find anything as simple as burning ammonia would be.
Interesting. From the first table, ammonia (stored at 10bar) is half the nominal price but a third of the energy density of gasoline. Apart from the toxicity issue we have very mature technology for turning petrol into mechanical energy.
Of course ammonia has been around for a very long time. If it was cost-effective to use it in the energy mix, someone would have done it by now.
Acid rain used to be attributed to sulphur in coal, when that was the dominant industrial energy source. There's still plenty of sulphur in bunker fuel but even ships now have to use desulphurised fuel within coastal limits. And petrol and diesel have been low sulphur for ages.
Nitrogen oxides are blamed more for poor air quality in cities, mostly I think derived from motor vehicles.
But of course if it was so obviously good, even in some niche market, someone would be using it by now.
When people mention the current ~70% conversion efficiency of green hydrogen, and suggest that "technology could improve that" they are forgetting that the lost 30% goes into the oxygen produced by electrolysis. Yes, you could capture that, but oxygen is not exactly in short supply and is currently a by-product of liquid nitrogen production.
Probably both, but NOx I think was responsible for photochemical smogs...along with unburnt hydrocarbons.
That was the first reason for getting excited about it.
The second is that at high levels near motorways and in urban situations it is a respiratory irritant. And can cause and exacerbate several lung conditions
As far as acid rain goes, its likely its far less an issue than sulphur dioxide. And nitrogen compounds make fertiliser so anything it reacted with would likely be beneficial to plants
You can't go drill a hole and pump it out of the ground - so it is a secondary fuel like Hydrogen - you need to use energy to make it, and will get back less when you burn it. Hence there is no attraction as a primary energy source.
However as a storage mechanism, it has a large energy density advantage over batteries.
I have wondered for a long time why huge container ships aren't nuclear powered, t would seem like an obvious thing to do.
However, I know nothing of the respective finances involved.
Cheers.
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