NH3

has anybody any experience with NH3 as a fuel. pro and con discussion http://www.nh3car.com/index.htm

Is this what you are talking about https://www.sciencem...-without-carbon

So as far as cars go, you split the ammonia into nitrogen and hydrogen, and then use the hydrogen in a conventional fuel cell.

If it works out on a commercial scale then it makes BEVs look a bit sad, in some cases. But all 3 processes are a bit underbaked at the moment - the ammonia production is inefficient (I don't care about that) and uses weird chemicals. How does a NH3->H2 reformulator work? how efficient is that (I do care about that). And finally fuel cells seem very do-able, but due to lack of fuel or purpose they are still fiendishly expensive. So I'd randomly guess 10-15 years from production if there are no major blockers.

CSIRO are working on pV to H2, ie electrolysis, but the problems there are known, and hard.

However if you mean burning it directly in engines then the big problem will be NOX. https://cen.acs.org/...s-planes/98/i31

You can also burn NH3 directly in an engine without splitting it first to its constituents. There's some research in using it in farm machinery, since ammonia is widely available and used for fertilizer production. There's also discussion about burning it in jet engines for aircraft and in ships (with modifications to the engines, of course) as carbon-neutral, sulphur-free alternatives to jet fuel and fuel oil, respectively.

As likely already covered in the above articles, the main headline attraction is carbon neutrality. However, most industrial ammonia is produced by the Haber–Bosch process, an endothermic process whose thermal energy resource typically comes from natural gas. The lifecycle is therefore decidedly not carbon neutral.

As a fuel in combustion engines, it has appreciably lower volumetric and gravimetric energy content compared to hydrocarbon fuels. Ammonia is said to have a high effective octane rating, but it burns with a very slow laminar flame speed. Ammonia slip through the exhaust (unreacted ammonia analogous to HC emissions) is extremely toxic in sufficient concentrations. It burns with a relatively cool flame, which is a positive for NOx emissions according to the Zeldovich Mechanism, but countering this effect is the much higher reactant concentration of nitrogen species, which shifts the reaction kinetics towards the product side (favouring NOx formation).

https://www.scienced...540748918306345

Is NOx a problem anywhere but cities (Sorry I'm feeling lazy)? If NOx is a city problem, and NH3 via a clean process is practical, then EVs for cities and cars, NH3 burners for long distance haulage and ag and edge cases where EVs don't cut it. (Quiet grin - the internal combustion engine lives on!). However that is a whole stack of ifs and unknowns.

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I for one follow Greg's optimism that ICEs will live on quite a while in the future - but maybe not in passenger cars or light-duty transport. I am writing papers for conferences (SAE and ASME) this year that will introduce ICE concepts that emit absolutely ZERO carbon, NOx, PM, HC and CO emissions. In one concept, the exhaust (water from burning hydrogen) is right around ambient pressure and temperature at the boiling point rather than several hundred degrees higher, which can be directly exploitable for CHP. Yet, the peak temperature of the cycle is over 3000 K. And it does this without any particular mechanical wizardry.

Sounds absurd? Stay tuned. 

Edited by TDIMeister, 04 February 2021 - 04:08.

Is NOx a problem anywhere but cities (Sorry I'm feeling lazy)? If NOx is a city problem, and NH3 via a clean process is practical, then EVs for cities and cars, NH3 burners for long distance haulage and ag and edge cases where EVs don't cut it. (Quiet grin - the internal combustion engine lives on!). However that is a whole stack of ifs and unknowns.

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NOX has a natural cycle from the effect of lightning 

https://www.scienced...on metric tons.

so if NH3 is a slow burner then prolonged constant volume and high swirl or both would be advantageous during combustion

Edited by malbear, 04 February 2021 - 04:10.

so if NH3 is a slow burner then prolonged constant volume and high swirl or both would be advantageous during combustion

I'm sure @manolis has concepts to address both.

I'm sure @manolis has concepts to address both.

so do I 

Is NOx a problem anywhere but cities (Sorry I'm feeling lazy)? If NOx is a city problem, and NH3 via a clean process is practical, then EVs for cities and cars, NH3 burners for long distance haulage and ag and edge cases where EVs don't cut it. (Quiet grin - the internal combustion engine lives on!). However that is a whole stack of ifs and unknowns.

You're right, Greg, NOx is arguably more of an urban problem because of the concentration of emitters, and also in certain geographic locations than others (e.g. the southern California airshed).

For NOx emissions, the proponents point out that ammonia-as-fuel already provides the required reactant for selective catalytic reduction (SCR) systems - the urea in AdBlue/DEF breaks down to NH3 at elevated temperature and it's the latter that is the active ingredient for SCR to reduce NOx.

NH3 slip can be (and is already) addressed in modern Diesel engines and powerplants with selective catalytic reduction systems equipped with a dedicated ammonia-slip catalyst, not much unlike the familiar oxidizing catalyst.

https://ac.umicore.c...-slip-catalyst/

so do I 

Do tell!

https://www.modernpo...-fuels-8912157/

Wartsila has launched a major test programme to advance the adoption of hydrogen and ammonia as viable engine fuels for power and marine applications through advanced testing on its fuel-flexible combustion engines.

Full-scale engine tests recently carried out in Wärtsilä's engine laboratory in Vaasa, Finland, to assess the optimum engine parameters for running on these fuels produced ‘very encouraging’ results, with one test engine performing very well when running on a fuel with 70% ammonia content at a typical marine load range. Tests were also completed successfully on another engine in pure hydrogen operation. 

Testing will continue throughout the coming years with the aim of defining the most feasible internal combustion engine-based solutions for both applications, helping to promote the transition to a decarbonised future with green fuels. 

For the energy market, Wärtsilä expects to have an engine and plant concept for pure hydrogen operation ready by 2025. For the marine market, it expects to have an engine running on an ammonia blend during this year, and having an engine concept with pure ammonia fuel in 2023. In the energy sector, it is anticipated that green hydrogen will deliver 7 % of the global energy demand by 2050.

Wärtsilä is also developing ammonia storage and supply systems as part of the?EU’s ShipFC project. It will begin testing ammonia in a marine four-stroke combustion engine together with customers Knutsen OAS, Repsol Norway and Equinor at the Sustainable Energy Catapult Centre in Stord, Norway, as part of the Demo2000 project.

Wärtsilä’s fuel agnostic approach enables the company to support the energy and marine sectors on how to shape sustainable, and efficient, future fuel strategies in several cost-optimal steps. For example, hydrogen can be used as a fuel in its existing state or as a raw material for producing a wide range of future fuels, including ammonia and synthetic methane, each of which has different benefits for industrial and mobility applications.  

The company’s engines can currently run on natural gas, biogas, synthetic methane or hydrogen blends of up to 25% hydrogen. An important property of future engines will be the ability to transition to future fuels, including pure hydrogen and ammonia, future-proofing customer assets.

The International Maritime Organisation (IMO) has set a target to reduce total greenhouse gas emissions from shipping by 50 % by 2050 compared to 2008 levels. In addition, a target has been set to reduce the carbon intensity of shipping by 40 % by 2030, thus emphasising the need for the rapid introduction of existing and new smart technologies. 

Edited by malbear, 22 July 2021 - 22:48.

You might like to delete half your post Mal?????

sorry mate . must be the ultimers or breathing the wood fire fumes 

I like the pretty graph, does the H2 production cost include the amazing energy input required to liquefy it?

OK I've just had a funny thought. If tying hydrogen to a carrier atom is such a good idea why don't we use the tried and trusted atom that can take 4 hydrogen atoms?

Edited by Greg Locock, 22 July 2021 - 23:34.

I like the pretty graph, does the H2 production cost include the amazing energy input required to liquefy it?

 

OK I've just had a funny thought. If tying hydrogen to a carrier atom is such a good idea why don't we use the tried and trusted atom that can take 4 hydrogen atoms?

CH4 production naturally how about we put plastic sheets on the tundra and collect it ?