Hydrogen transport as ammonia

Some here might find this an interesting idea.

Clifford Heath.

Reply to
Clifford Heath
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The comment about having to move 34 kgm of ammonia to deliver 6kgm of hydrogen is germane.

And while we can and do shift lots of ammonia around, it is nasty stuff.

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Bill Sloman, Sydney
Reply to
bill.sloman

It makes more sense to link it to carbon. The resulting stuff is easy to handle, relatively non-toxic and packs a lot energy in a small volume. And the carbon actually adds to the energy density, contrary to the nitrogen in ammonia! Oh wait, we're already doing that...

Jeroen Belleman

Reply to
Jeroen Belleman

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** Hydrocarbons ( natural, underground ones) = stored sunlight.

..... Phil

Reply to
Phil Allison

1kg is bad enough, I'd hate to be anywhere near a 34kg release.

NT

Reply to
tabbypurr

ydrogen is germane.

.

There's this minor problem with generating even more greenhouse gas than we have already done. If we thermally cracked the hydrocarbons to carbon and hydrogen, we'd avoid this problem, but carbon is a solid (up to quite high temperatures) and would clog up those nice membranes.

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Bill Sloman, Sydney
Reply to
bill.sloman

lengthened chains of hydrocarbon-molecules

stored sunlight, tsk....

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Daniel Mandic
Reply to
Daniel Mandic

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** Warning:

Daniel is a trolling, mental defective.

Likely both autistic and schizoid.

Now he is net stalking.

Use you kill file.

You will not miss anything.

.... Phil

Reply to
Phil Allison

ydrogen is germane.

.

The molecular weight of ammonia is 17.031 g/mol, so 1kgm is 58.7 moles. One mole occupies 22.4 litres at standard temperature and pressure, so 58.7 mo les occupy 1,352 litres or 1.352 cubic metre.

Since your own volume is only about 100 litres, you could well be surrounde d by that much ammonia, which wouldn't be enjoyable. Don't inhale.

The flammable range of ammonia in air is 16?25% so don't strike any matches while getting away, though it's pretty hard to light.

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Bill Sloman, Sydney
Reply to
bill.sloman

Hydrogen is not easy stuff to transport. It is very hard to make hydrogen tight containers. I can only imagine the accidents we would have if hydrogen were to be shipped around the way we ship crude oil.

I'm not sure the weight of the nitrogen is really that important. The issue is not how much does ammonia weigh compared to hydrogen, but how much does it weigh compared to other fuels in terms of the energy content. Ammonia is about the same as Methanol which is about half the density of octane. So while it is not quite as good as transporting gasoline, it is in the ballpark. It's hard to compare to crude oil since crude oil has many fractions that are not as useful for heating and can't be used for automotive fuel.

What is really relevant is the total efficiency of the generation/transportation/recovery system which we won't know for some time to come. As the paper points out, this would be taking advantage of existing transportation methods which would obviously have to scale up for widespread use as a transportation fuel.

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Rick C
Reply to
rickman

:

hydrogen is germane.

ff.

ne mole occupies 22.4 litres at standard temperature and pressure, so 58.7 moles occupy 1,352 litres or 1.352 cubic metre.

ded by that much ammonia, which wouldn't be enjoyable. Don't inhale.

ny matches while getting away, though it's pretty hard to light.

Ammonia is fatal at concentrations far below 100%. Serious reservations hav e been expressed about the safety of 1kg ammonia minifridges in hotels on t he grounds that a release would likely cause several deaths. In practice su ch releases have not occurred so it continued to be permitted. What happens if they're still installed 50 years later & heavily rusted I don't know.

NT

Reply to
tabbypurr

Hydrogen does have that advantage that hydrogen spills clean themselves up without any environmental damage - assuming there are no sparks at awkward moments.

All good points.

Using ammonia has the benefit that the waste product - nitrogen - can be freely released into the atmosphere. This is an advantage compared to trapping hydrogen in other carriers. Of course, that assumes that the eggheads here have found a way to get /all/ the hydrogen out of the ammonia.

According to Wikipedia, the raw energy density of liquid ammonia is about a third that of diesel.

Reply to
David Brown

It's not like the processed ammonia products are released to the air like automotive exhaust. They would be recirculated back into the cracking process. The molecular filter would be a very effective way of purifying the hydrogen products.

Diesel is a fuel obtained *after* processing and is not typically transported from sources like crude oil. Of course ammonia is created by processing other sources of power, but that is functionally equivalent to drilling and pumping the oil. Crude oil is how petroleum is shipped around the world. Then the various production products are distributed over typically shorter distances.

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Rick C
Reply to
rickman

AFAIK ammonia in non-commercial refrigerators or air conditioning has not been allowed in the US for many-many-many years. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

That will work, if they have a way of separating the ammonia from the nitrogen (which can be released into the air). I suppose that should not be too hard - most of the nitrogen should bubble out of the mixture as gas.

A major issue is the final storage - the car's fuel tank. I am thinking mainly of that step - people would need three times bigger fuel tanks to get the same mileage from ammonia as from diesel.

Reply to
David Brown

The energy in hydrogen is there because it is in its molecular form, and not oxidized.

Ammonia is hydrogen that has been oxidized by nitrogen. So that "decomposed ammonia" in their chart didn't happen by magic -- energy had to have been put INTO the ammonia to decompose it.

I don't have the chemistry chops to tell you how much energy is necessary to decompose ammonia, but I suspect the process isn't efficient. It may well be an economically viable way to process ammonia into hydrogen -- but without an energy budget, all the pretty animated pictures in the world still sum up to a big pile of BS.

And while BS is a better fertilizer than just ammonia (more micro- nutrients, for one), it's still BS.

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Tim Wescott 
Wescott Design Services 
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Reply to
Tim Wescott

Hydrogen is easy to transport. Just attach it 4:1 to carbon. It even comes free just like that, and it's easy to separate.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Ammonia is nasty stuff, lethal at 500 PPM in air.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Ammonia has a significant energy content. To produce hydrogen molecules will require some energy addition, but not as much as releasing hydrogen from water. When burned with air hydrogen produces water.

I'm surprised you are commenting on this given that you acknowledge your chemistry limitation. First learn the distinction between oxidation and the energy levels of molecules. We think of oxidation as being an exothermic reaction, but the two things are not equivalent. The bottom line is that we currently have many steps in the process of creating fuel for our autos. They all consume energy. Using ammonia as a transportation medium for hydrogen is not an absurd idea with fundamental impossibilities. Certainly it is too early to know if it is a viable transport, but it may well be practical.

The real issue is what source of energy will be used to generate the ammonia? I vote for Thorium based nuclear or at least researching the idea to determine if it is practical or not.

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Rick C
Reply to
rickman

John Larkin wrote on 6/7/2017 11:20 AM:

Too bad we already have problems dealing with the carbon we have released into the air. While John seems to think ever higher levels of CO2 in the air is nothing we should worry about, the facts say otherwise. But that is mostly because the places he inhabits are well above sea level.

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Rick C
Reply to
rickman

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