Hydrogen transport as ammonia

You might find this of interest:

It seems there is a way to remove the carbon without clogging.

I guess we'll know when it's commercially viable when Warren Buffett starts buying up the world's tin stocks.

--

Jeff

I remember seeing an old black-and-white television show back in the

1960s (soon after my family got its first TV) which involved an industrial accident with one of the big ammonia-charged refrigeration systems in use then.

One character said something to the effect of "A man can survive breathing ammonia-poisoned air for about an hour. And, it'll be the most horrible hour of his life."

For an interesting look at the use of ammonia (and other exotic materials) as fuels, dig around and find a copy of "Ignition!" by John D. Clark (there's a PDF of it on-line somewhere). Rocket engineers have long been on a quest for high-energy, high-impulse fuels for rockets... and a lot of the molecules they've played around with make liquid ammonia seem like a breath of fresh spring-time air in the mountains.

(e.g. some semi-lunatics tried using mixed mercaptans as rocket fuel... there was lots of it available from petroleum refiners and it looked halfway-decent, energetically. Didn't work out all that well, and the stench discouraged further research.)

On Wednesday, June 7, 2017 at 7:45:38 AM UTC-7, Jim Thompson wrote: ...

...

It's not used for fridges or A/C with a compressor but the absorption cycle

is still used where heat is available but adequate electricity isn't (e.g. RVs).

The ammonia is cyclicly dissolved in water then boiled off by the heat source.

kevin

I worked on a project MANY years ago. They had a few good ideas. One was, if you put water under enough pressure so it remained liquid at some insane temperature, the energy required to split it by electrolysis was minute. Since the cell was already at high pressure and temperature, you had a stream of hot hydrogen gas, so you could use that to make ammonia with no additional energy input. The solar energy could directly heat the cell. So, all the energy you needed to supply the system was a high pressure pump, like a feedwater pump on a boiler. The design they were working from was totally glod-plated NASA type stuff, with platinum electrodes, sapphire insulators and all sorts of insanely expensive materials. Our Prof. said that most of that could be replaced with reasonable alternatives like ceramics, but that platinum PLATED electrodes might still be needed. We got an 18 foot radar dish and mounted it on a surplus searchlight mount. We polished the dish, and it would melt steel placed at the focus. Then, the prof jumped to another university.

Ammonia is actually really NASTY stuff! It is corrosive, poisonous, and explosively flammable. Large refrigeration systems used to use it, but the amount of protective design they need make them pretty non-cost effective today. I can't imagine the issues with having "ammonia stations" to fill up your car's fuel tank.

On the other hand, farmers use liquid ammonia to fertilize their fields, which was part of the plan of that project I worked on.

Jon

If you want to move something in a pipeline, hydrogen makes more sense without all the additives. It can go straight into a fuel cell, and takes less pump pressure and pipe girth than the alternatives.

It's also safer than heavier molecules, because it doesn't fill valleys or enclosed spaces, but rises and disperses.

Hydrogen can be adsorbed on/into certain metals. We had a high-tech hydrogen tank for use in aircraft to supply an instrument that used a hydrogen flame. it stored hydrogen in crushed titanium metal, I believe. Lithium and Magnesium can also be used. An aluminum tank filled with the powdered metal held the same amount of gas as a steel tank the same size. But, the adsorption tank weighed something like HALF the steel tank, even though it was filled with a light metal. It stored the same gas at less than 300 PSI as the steel tank did at about 1500 PSI. (Due to hydrogen embrittlement, you can't put 2500 - 3500 PSI of hydrogen in a steel tank, as you can with most other gases.)

This type of tank has been proposed for hydrogen-fueled vehicles, and a few have been tested. The adsorption tanks work fine for driving the vehicle, as the gas is used slowly. The problem is they can't be filled quickly, as the powdered metal has to adsorb the gas, and that is an exothermic reaction. You have to actively cool the tank while it is filling, and it takes at least a couple hours.

Jon

The inverse is true, also; a leaky tank won't empty quickly, because the desorption is endothermic, it freezes the storage medium and chokes the effluent gas flow. This is a 'feature' rather than a 'problem'.

For quick fueling, you'd want to swap cartridges. The filling stations would then reinspect the tanks (no point in refilling a bad 'un).

I'm not certain that would be any safer if that is the goal. Lithium is

*definitely* serious fire hazard that can't be put out without difficulty. magnesium may not be as easy to ignite, but it is still very dangerous once lit. I recall using a series of powered metals to weld bond wires to rails to couple electricity across the joints. We used a sparker to ignite the magnesium which then ignited the aluminum which melted the third ingredient which I don't recall for sure, but may have been steel. But you see the point. Powered lithium and magnesium are not something you want to have in the trunk of your car in an accident! It would make the Ford Pinto look like the safest car in the world in comparison.

--

Rick C

Den onsdag den 7. juni 2017 kl. 22.17.31 UTC+2 skrev rickman:

aluminium powder and iron oxide, aka. thermite

Even with a spark, it would still clean itself up, but would give the immediate surroundings a thorough cleaning too :)

Any idea what percentage of the total stored capacity is wasted by the cooling process? I'm assuming that you don't need to heat it to get adequate output volume for normal earth surface temperatures??? Maybe it's the air conditioning system.

How would those numbers compare to the charge/discharge losses in a Tesla Lithium Ion power pack?

Would also be interesting to know the efficiency of converting hydrogen to motion compared to something like Tesla technology.

Any time you put a lot of energy into a small space, you've got a bomb. We routinely drive gasoline bombs around. But we're afraid of other technologies of similar energy density. The endothermic hydrogen release process sounds like a very good thing.

*IF* you could get a similar energy density. *IF* the costs are comparable. *IF* it doesn't scare a lefty.

flammable fuel/air ratio by volume: gasoline: 1.4% to 7.6% hydrogen: 4% to 75%

Gasoline vapor is heavier than air so tends to collect at ground level. Hydrogen is a lot lighter than air (duh!) so dissipates rapidly. The Hindenberg gave hydrogen an undeserved bad name. Hydrogen wasn't the problem, even.

A good point! I don't know, as we were more concerned with weight and safety than efficiency. It is not a huge amount of energy, so I'm guessing it might be less than loss in some battery's charge/discharge loss. I'm guessing you could look this up, there's been a fair amount of research on hydrogen storage. The nuclear weapons guys prefer lithium, but then that is part of the nuclear reaction (neutrons + Li => Tritium) so maybe no need to use lithium.

Well, some of the fuel cells are supposed to be pretty efficient. But, they might need super expensive catalysts to work that way. Crooks steal catalytic converters to get a fraction of an ounce of Pt. Imagine the problems with carrying around a Pound of Pt in your car!

One of the problems with hydrogen is it is odorless. Maybe they could put an odorant into it so it would be detectable - like natural gas.

Jon

Lasse Langwadt Christensen wrote on 6/7/2017 5:09 PM:

Thanks for the link. That was welding the rails together which is a much bigger job than what we did. I worked with the signal gang and we were just welding a bond wire across a bolted joint, a much smaller rig. I recall the metal powders were in a plastic case about the size of a 35 mm film roll and you could see the layers of metal. I thought there were three layers, but maybe I was mistaken and it was just two, the magnesium and the thermite. It wasn't as flashy as the video you showed, but still impressive with fire shooting out of the mold.

I guess they don't use bond wires so much now. They just weld the rail. But they have to leave some joints to allow expansion of the rails. That's why the rails are not hard connected to the ties. I see they are using concrete ties now. The railroad had not changed much in the 100 years before I worked there. I guess they finally have started to make a few changes.

--

Rick C

Den torsdag den 8. juni 2017 kl. 01.02.36 UTC+2 skrev rickman:

this is quite the contraption,

Lasse Langwadt Christensen wrote on 6/7/2017 7:24 PM:

Wow! It's hard to imagine a railroad executive approving the delivery of ties by tractor trailer! But that's what they were doing.

--

Rick C

There was some comment about that in the discussion. Apparently the issue is that if you try to bring the ties in by rail, you end up having to stop the train to remove the empty cars to go back to the depot and then hook up the new (full) ones. If you use trucks, they can be unloaded from the trucks and moved onto the empty cars on the train "on the roll" without stopping anything.

I suppose you could bring 'em into the area by rail, and then just use tractor-trailers as shuttles. Might or might not be cost-effective, depending on how fast you can "turn around" each new supply train (which would block the line while it was being unloaded).