How ammonia could help clean up global shipping

Just the merest trifle. If you've ever sniffed real ammonia, you'd know the stuff is very nasty indeed. At least it's not subtle, so it won't intoxicate you unnoticed. It kicks, really.

Jeroen Belleman

Ammonia production is endothermic, yes, and we need lots of it, though not as a fuel.

Jeroen Belleman

Nobody suggested using ammonia as combustion fuel.

That's because the hydrogen for the Haber-Bosch process comes from natural gas (methane). Under these circumstances ammonia makes no sense as a hydrogen carrier -- you might indeed just burn the methane right away. The process becomes interesting when the hydrogen is created from wather with renewables, with ammonia being used as a high-density transport / storage medium for hydrogen.

The ammonia idea only makes sense if the hydrogen comes from renewable sources.

see above.

Cool. Solar panels, electrolysis to make hydrogen, then solar powered ammonia synthesis. No worries about efficiency since solar power is free.

but they are ..

How would a ship use ammonia for propulsion?

Pistons in cylinders, ammonia/air/catalyst mixture, ignition source, crankshaft... not lots of RPMs, those cylinders are BIG and there's plenty of time for complete combustion.

It isn't. It is cheaper than any other way of making electricity, and a bunch of Australian venture capitalists are raising money to build huge solar farms on the north coast of Australia to make hydrogen by electrolysis, to be liquified and shipped off in tankers to South Korea and Japan.'

Somewhat more sensible people are planning on building more solar farms up there and shipping the electricity they produce to Singapore over a rather long high voltage undersea cable. They will need grid scale batteries - probably vanadium flow cells - to keep the current flowing over night and during overcast days.

That means a somewhat oversized solar farm, but they can probably sell the excess current (when they've got it ) to a hydrogen generating farm down the coast.

John Larkin can't see much. He never seems to have been exposed to thermodynamics.

At least Wärtsilä working on ammonia engines. They've already got diesel, methanol, LNG and dual fuel motors.

Of course, basically a modified giant direct-drive reversing diesel. I was responding to the statement

I used to design control systems for big-ship steam turbines. The first closed-loop controller I ever designed (I was an EE undergrad) was 32K horsepower. I used the newish uA709 opamps. Steam turbines were efficient and the fuel was "dirt" cheap but the plants were so complex that it got hard to find crews to keep them going. Big-jug diesels are much simpler.

Up until sorta recently, I had a blueline copier that used an ammonia developer. If you unscrewed the cap from a gallon jug of the ammonia solution, the vapor would sting your fingers.

I still have a drawing table and design with a pencil on D-size paper, but I photograph the schematics with my phone.

I think there was once a piston engine that sprayed powdered coal into the cylinder.

How about wood chips?

What about the ashes?

Jeroen Belleman

Probably the ashes from ammonia burning are N2 gas and H2O vapor, so go out the 'smokestack' looking like... steam. And from a wood chips burner, also out the 'smokestack' smelling like a forest fire and looking like soot.

I'd expect ashes to play havoc with lubrication. That doesn't look good for a piston engine.

Anecdote: Nicéphore Niépce, one of the early inventors of IC engines, ran his invention on lycopodium.

Jeroen Belleman

If you were really interested you'd just read the cited "chemistryworld" article which gives a pretty good overview of the potential benefits of the method as well as its shortcomings and risks. It answers or at least addresses every question you've come up with so far.

Using ammonia as a fuel is madness, I repeat. It's a nasty toxic substance. It's nowhere found in useful quantities in nature. It has to be made, which is inherently wasteful. You can't simply burn it, because that would produce nitrogen oxides. It not a viable alternative to petroleum. It's worse. Much worse. Don't believe the green hype. They're wrong.

Jeroen Belleman