Ammonia-derived Hydrogen Fuel Vehicle

This might be the breakthrough for electric vehicles. I wonder if this and Elon's announcement to go private with Tesla motors have any correlation?

Interesting timing....there's sure to be a lot of speculation....The fuel cell Tesla?

found this tidbit....from last year

..."Gas company claims to have converted a Tesla to hydrogen fuel cells. ... They claim to have converted a Tesla Model S to a hydrogen fuel cell power train and they want to sell the conversion package. The Holthausen Group, better known as a gas supplier, is also dabbling with hydrogen stations and fuel cell vehicles."...

The Hesla?

https://electrek.co/2017/11/06/tesla-converted-model-s-hydrogen-fuel-cells/

Yeah why?

https://www.quora.com/Why-doesnt-Tesla-use-a-fuel-cell-in-its-cars

These folks make the argument for using NH₃ as a fuel in place of hydrogen. The energy per volume is a little over 1/3 that of gasoline but about 1 1/2 as much energy as liquid hydrogen, but it is much easier to handle than liquid hydrogen and has no carbon content. For energy per dollar, it is competitive with gasoline, according to the article.

https://nh3fuelassociation.org/comparisons/

I am really confused with these reports and the CSIRO site is not any clearer.

So I think that they are going for 'green' ammonia with renewable electrolysis of water for H2 and super high quality membranes for the N2. Then react with catlyst at high temp.

So far so groovy.

Then ship liquid ammonia at higher temp lower pressure higher density (and higher energy density) than liquid hydrogen via existing shipping networks. This makes so much sense ammonia is well known all the procedures for shipping and handling are available the vehicles, ships train tanks to ship it are available etc

Ditto on the groovy front

Then it gets a bit wishy washy

It is not possible toseparate hydrogen from ammonia using a membrane. The Haber-Bosch reaction has to be reversed. That would be an endothermic reaction. So it is possible to do this and overall the NH3 -> N2 + H2O is very exothermic.

But is it done at the fuelling station so that you still fuel vehicles with hydrogen? I thought reading this that the idea was that you would fuel the vehicles with ammonia and then in a 2 stage process generate hydrogen on board and then power int he fuel cell.

I am surprised membranes can produce the required purity in sufficient quantity but they are always imprvng them and there is a size diff between hydrogen molecules and anything else.

If the ammonia splitting occurs at the fuel station they will need power for that stage and then power to compress the hydrogen for filling the vehicle.

It just seems theres a few steps being glossed over.

Also ammonia isn't exactly benign - toxic, corrosive and flammable!

Before reading the details, I had the impression that NH3 would be transferred to the vehicle and an onboard catalytic reaction would separate the Hydrogen for the fuel cell. Separating at the filling station still leaves the logistic problem of how one stores Hydrogen on a moving vehicle.

This led me to another thought. Since NH3 is itself combustible, why not burn this in an ICE? Somebody is exploring this, too.

A 50 to 1 compression ratio would be an engineering challenge. Economically produce alloys that have long life expectancy in extreme environments. Standard ICE engines would get a bit heavier.

That's why the researcher searched and found a way to reduce the compression to 35:1. This still exceeds today's diesel engine compression but only by a factor of less than two. It also will produce NOx production complications at this ratio.

If it was easy to do, it would already be done.

Your tank will have to be about 3 times as large for the same range. The energy content of NH₃ is 41,700 BTU/gal versus 114,100 BTU/gal for gasoline and 129,500 BTU/gal for diesel fuel.

https://nh3fuelassociation.org/comparisons/

And then there,s that....

With NH3 a third of the enegry density of gasoline, it still is an order of magnitude greater energy density than lithium batteries.

There is no single holy grail answer without any drawbacks out there. We should explore all options, first.

It seems to me a fuel cell application would be much more efficient than an ICE using any fuel....because of the electric motor efficiency advantage, so less btu requirement per mile....

https://batteryuniversity.com/index.php/learn/article/bu_1005_fuel_cell_vehicle

Seems to me the Ammonia could be shipped to distribution plants, and converted on-site...Ideally then pipeline distribution to different key geographic locations....

https://en.wikipedia.org/wiki/Hydrogen_production

http://www.ammoniaenergy.org/progress-toward-ammonia-to-hydrogen-conversion-at-h2-fueling-stations/

I am always a bit reticent when it comes to extremely explosive gasses anyway. Especially out on Americas bumper car tracks. If the roads don't get you the drivers will.

Liquid ammonia, pressure (in bars) vs temperature Centigrade. For example, 30 deg C = 86 deg F, pressure = 11.5 bar = 169 psi

Not only will your fuel tank need to be 3 times as large, but considerably stronger to withstand internal pressure when the car is parked in a hot parking lot, and strong enough to survive a road accident.

the beauty of hydrogen is that it is so light that as soon as the tank ruptures, it is far above the vehicle. and i would imagine the tank would be stored on the roof of the vehicles. unlike gasoline which spills on the ground and then vapors erupt in flames. Frankly, it amazes me that there are not many more fatalities caused by gasoline fires at the scene of an accident.

Not sure these folks would agree with you. Yes the fire went up.

AFAIK what you're seeing is the fire from the aluminum dope of the airship skin burning. Hydrogen burns with a faint blue flame that becomes hard to see in direct sunlight let alone such a conflagration. This nearly invisible flame is one of the significant risks of hydrogen fuel.

Too true, My 67 Mustang has a two piece clamshell welded gas tank.

This tank is mounted between the rear subframes aft of the rear axle.

It's filler was up off the top of the tank connected with a rubber hose and two tractor clamps to the receiver which was through the center of the taillight panel just above the rear bumper, which if you remember was solid chrome plated steel bolted directly to the same subframe that also held the gas tank, which as a money saving feature, also comprised the floor of the trunk. Fairlanes, Falcons, Mustangs, Pintos, Cougars all had this set up and yet only the Pinto became famous for it.

makes no sense to put the cracker at the filling station. Hydrogen is way too hard to keep from leaking out of every orifice and thru lightweight carbon wound pressure tanks.