Ammonia as Internal Combustion Engine Fuel

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To save hijacking JCGs EV1 thread any further I'm continuing here:
This is an interesting article:
http://www.opednews.com/articles/American-Energy-Policy-Par-by-Paul-from-Potomac-100716-21.html
particularly this:
"Q) Has ammonia ever been used in a public setting on a large, municipal scale?

A)The St. Charles Avenue Line began operation in 1833 running street cars through the heart of New Orleans. It starts uptown, at South Carrollton Avenue and South Claiborne Avenue. It runs on South Carrollton Avenue through the Carrollton neighborhood towards the Mississippi River, then near the river levee turns on to Saint Charles Avenue. It proceeds past entrances to Audubon Park, Tulane University and Loyola University New Orleans, continues through Uptown New Orleans including the Garden District, and ends at Canal Street in the New Orleans Central Business District at the edge of the French Quarter, a distance of about seven and a half miles.

The reason I bring this up is to blow smoke in the face of our fossilized friends. It was powered entirely with anhydrous ammonia for 60 years until it was electrified in 1893. It had no carbon emissions whatsoever. In the late 19th century, public transit throughout Europe used ammonia -powered street cars.
"
 
Ammonia: The Fuel for the Hydrogen Economy
http://www.voxsolaris.com/ammonia.html
The Ammonia economy

Ammonia suffers from none of the storage and transportation problems posed by hydrogen. Insted of needing tanks capable of withstanding enormous pressure, ammonia is a liquid at ordinary temperatures when pressurized to a mere 8 atmospheres and there is no tendancy for ammonia to pervade the walls of the tank. This is comparable to LPG and means we can use cheap, reliable tanks that last and do not require regular intensive inspection.

Converting hydrogen to ammonia does involve an energy cost that is higher than the cost of compression but only a fraction of that of liquifaction. This matters but if you have a carbon free source of hydrogen that is economic, this energy cost is acceptable if it results in a fuel that is cheap to transport and store. Another drawback is that compared to gasoline, an ammonia tank would occupy nearly 3 times the volume and be twice the weight. A headache for car designers yes but a blazing migraine no. A serious challenge for aircraft designers certainly, but a plauability rather than an inplausibility. The hydrogen economy was never going to come for free but the drawbacks of ammonia are in our view an acceptable price to pay for carbon neutrality. And compared to compressed hydrogen or the even worse liquid hydrogen, ammonia is a dream.
 
And it's all quantified here:
http://www.google.co.uk/url?sa=t&source=web&cd=4&ved=0CCcQFjAD&url=http%3A%2F%2Fphp.teamem.com%2Ffreedomfertilizer.com%2Ffiles%2Ffinal-wind-to-ammonia_031208.2.pdf&rct=j&q=wind%20to%20ammonia%20how%20much%20could%20be%20made&ei=M_dWTJ3tJ8qL4QbQ3bWnBQ&usg=AFQjCNFd0c91ABtNEJKLZzAThG2YvANoWw
 
Interesting, Paul. Just a note, most of the ammonia made in the US uses methane (called natural gas here) as the feedstock to produce ammonia. Though, clearly, there are several ways to make ammonia.
 
Fascinating. I didn't know that about ammonia.

However,

"It is actually more meaningful to compare ammonia not to gasoline but to LPG as both are ligufied gasses under pressure. Tank rupture is clearly seen as being a very small risk by authorities charged with ensuring safty. If this were not the case there would not be LPG cars. In the event of a rupture, LPG is not going to poison anyone as ammonia could, but on the other hand, ammonia is much less likely to turn people into kebabs. With an ignition temperature in the region of 700°C, ammonia outside an engine, is essentially inflamable. "

I think he might mean "not flamable".
 
If you dont mind huge scale acid rain, ammonia is an ok fuel. The NOx emmisions are sky high with it (meaning, add water vapor, one of its combustion products, and you've got yourself Nitric Acid.) NOx cats/scrubbers are kinda a joke, and generally just involve trying to neutralize the acids with some base like ammonia to begin with.

From an energy and polution perspective, ethanol and methanol both make a lot more sense, and both have minimal NOx emmisions.
 
As LiveForPhysics said,

The creation of nitric acid (HNO3) from combustion of ammonia:

Nitrogen and water produced from the burn.
  • 4 NH3 + 3 O2 → 2 N2 + 6 H2O
One possible way to nitrogen fixation is by lightning. (Birkeland-Eyde process)
  • N2 + O2 → 2 NO
Upon cooling we have nitrogen dioxide.
  • 2 NO + O2 → 2 NO2
And finally from dissolving in rain we get the nitric acid.
  • 3 NO2 + H2O → 2 HNO3 + NO

Bit harsh on metals. Then again the atmosphere is made up of 78% nitrogen. All in all a good read and something I hadn't investigated much until reading this post. I think it's definitely a viable alternative. But, better would be methanol! 8) Methanol can also be made from AIR and WATER via a similar approach to the Fischer–Tropsch process. Easy:

Calcium oxide in contact with air absorbs CO2 to become calcium carbonate.
  • CaO + CO2 → CaCO3
The calcium carbonate is heated by solar mirrors or hydrogen furnace to release the CO2.
  • CaCO3 → CaO + CO2; 848 °C
Electrolysis of water gives hydrogen and oxygen by solar panels or wind turbines.
  • 2 H2O → 2 H2 + O2; E0 = +1.229 V
The CO2 and H2 combine via catalytic hydrogenation to form methanol.
  • CO2 + 3H2 → CH3OH + H2O

Very similar process to the ammonia synthesis, just filtering CO2 instead of N2 and using a copper catalyst instead of iron. You could also use biomass, and not just food crops such as needed by the ethanol economy.

Biomass → Syngas (CO, CO2, H2) → CH3OH

Germans were producing about 25% of their auto fuel from a similar process back in the 30's. Not many infrastructure changes would be needed as we are accustomed to liquid fuels. I believe many types of auto racing rely on methanol as the main fuel as well as some RC cars and planes. Methanol fuel cell for electricity production = cool. And although methanol does release CO2 on combustion it IS carbon neutral when you capture the CO2 from the air or chimney and use renewable energy resources to synthesize it.

I currently have some of the apparatus complete for this process. I'll do a write up one of these days when I get around to finishing it.

Cheers,
JS
 
Yep, methanol is way way better. :) To meet the same power needs, the engine can be under half the physical size/weight of an ammonia engine as well. But, it does require way more frequent oil changes. Lol
 
Both ethanol and methanol are derived from fossil fuels and produce greenhouse gases (CO2) on burning. They are INFERIOR to ammonia which can be made from water electrolysed by windpower and nitrogen distilled from the air as described in the articles I posted. Have a nice day!
 
Both can be made 100% carbon neutral from wind or any energy source (but neither are.) The methanol just doesnt cause massive acid rain.

You may think normal car exhaust sinks to be stuck behind. Ammonia car exhaust could cause intense pain and blinding from a single exposure... Nitric acid is no joke.


paultrafalgar said:
Both ethanol and methanol are derived from fossil fuels and produce greenhouse gases (CO2) on burning. They are INFERIOR to ammonia which can be made from water electrolysed by windpower and nitrogen distilled from the air as described in the articles I posted. Have a nice day!
 
If you read this LFP you'll see that ammonia is being used to REDUCE emissions of NOx not increase it!
http://www.glgroup.com/News/Navistar-Hedges-its-Emissions-Bet-with-Amminex-45820.html
 
Production started on 7th June:
http://newenergyandfuel.com/http:/newenergyandfuel/com/2010/06/15/wind-to-fertilizer-construction-begins/
 
Re-read my first post in this thread. Lol


paultrafalgar said:
If you read this LFP you'll see that ammonia is being used to REDUCE emissions of NOx not increase it!
http://www.glgroup.com/News/Navistar-Hedges-its-Emissions-Bet-with-Amminex-45820.html
 
Well, i guess if they've got a boat load of available energy, and dont mind a process that is going to be lucky to be 5-10% efficient with the use of the energy (energy into making NH3 vs potential energy return through combustion in an ICE), then its a win. :)



paultrafalgar said:
Production started on 7th June:
http://newenergyandfuel.com/http:/newenergyandfuel/com/2010/06/15/wind-to-fertilizer-construction-begins/
 
Here's a strange coincidence: two interests of mine coalesce:
http://ubuntuforums.org/showthread.php?s=90cae5b7fbd68bccdf04902dd9f48c85&t=1533675
...edit:
this link was interesting:
http://investorshub.advfn.com/boards/read_msg.aspx?message_id=43995541
...edit:
and so is this:
http://nh3car.com/index.htm
 
johnrobholmes said:
I bet burning ammonia smells awesome!

:) You dont wana go sniffing it much bro! End up blind with internally bleeding acid lungs. Lol.
 
Methanol is much better, it only causes blindness. 8)
 
Thanks for helping me find your thread here Paul. I wasn't too sure that any discussion of alternative combustion fuels belonged in an electric vehicle forum on its own, so I always tried not to elaborate on the topic when I mentioned it in other places. But, it looks like there are a few people who took some general chemistry in college (at least). I think I can provide some information that will help, because there are some common misconceptions here.

liveforphysics said:
If you dont mind huge scale acid rain, ammonia is an ok fuel. The NOx emmisions are sky high with it (meaning, add water vapor, one of its combustion products, and you've got yourself Nitric Acid.)

Acid rain? Ridiculous. Absolutely not the case. It is actually very difficult to partially oxidize ammonia into the various nitrogen oxides when burning it with a flame or within a spark-ignited cylinder. At typical flame temperatures, the preferred route by far is the first reaction listed by jsplifer:

4 NH3 + 3 O2 → 2 N2 + 6 H2O = Nitrogen and water produced from the burn.

It is desirable to produce NOx, for example, when you are making nitric acid (or later, fertilizers). The precursor is still ammonia, however the partial oxidation is carried out heterogeneously; over a supported catalyst like platinum. These combustion reactions are cooler, and will produce more NO than a flame ever could, due to the limited number of surface reaction steps that occur (and different metals will produce different ratios of product gases). Pt is one of the best for NO.
(Further reading, see under "preparation")

liveforphysics said:
NOx cats/scrubbers are kinda a joke, and generally just involve trying to neutralize the acids with some base like ammonia to begin with.

I don't think that the two of you are talking about the same thing. Paul is correct when he states that ammonia is used commercially (e.g. in power plants) for NOx abatement. It also is able to convert sulfur oxides (the real source of acid rain) into solid sulfates. The general process is termed "selective catalytic reduction," and uses a supported metal catalyst (usually vanadium-based in this case) much like the catalytic burning by Pt I mentioned above. Ammonia is one of the best reducing agents available for gas treatment. It will convert a partially oxidized nitrogen atom and reduce it to harmless nitrogen gas (N2), with water as the other end product. And I mean both common NOx gases, either separately or if present together:

4NO + 4NH3 + 3O2 → 4N2 + 6H2O
2NO2 + 4NH3 + 3O2 → 3N2 + 6H2O
NO + NO2 + 2NH3 → 2N2 + 3H2O

What this means is that by simple tuning of the air/fuel ratio of the combustion engine (or alternatively fuel bypass), you can provide sufficient excess ammonia to neutralize, in the same manner as an automotive catalytic converter, any residual NOx.

No joke.

johnrobholmes said:
I bet burning ammonia smells awesome!

Ammonia flames are odorless. I've stood right above them, no detectable ammonia. Just water, nitrogen, and any existing NOx well below the nose's detection limit (probably in the ppb range, though). We have even cooked food over an open ammonia flame. See slides 5-7 and 25.


liveforphysics said:
From an energy and polution perspective, ethanol and methanol both make a lot more sense, and both have minimal NOx emmisions.

Ignoring the pollution comment, I would agree that methanol is a good alternative fuel choice. It's liquid, ready to be used (albeit at relatively poor efficiency) in a fuel cell, and is possible to produce from renewables. It's also only somewhat toxic which is good. Ethanol is very hotly debated in terms of its net energy return (depending mostly on its bio-based source). Ethanol is somewhat unstable in metallic tank storage and very tough to transport due to its tendency to degrade into acetaldehyde. Piplining ethanol would be a real materials challenge. Methanol not as much. But once again, that tricky carbon atom is going to be part of the cycle and needs to be taken care of. Collecting stack gas may work for a power plant (although that also has problems for implementing), but you will never be able to gather the CO2 straight from your car's tailpipe. It'll get into the atmosphere where you can recover it later, but you spend a lot more energy recovering it from a diluted source like the atmosphere. One of the beauties of an ammonia economy is the potential complete lack of carbon in the cycle. Of course, it's also a liquid, produced in very high volume, routinely handled, usable directly in a fuel cell, has a pipeline system in use today, etc. Specific energy of methanol is 19.7 MJ/kg, ammonia is 18.6 MJ/kg. Very comparable, and it's preferable to do without the carbon.

liveforphysics said:
Both can be made 100% carbon neutral from wind or any energy source (but neither are.)

Before Haber-Bosch came into its own, most of Europe's ammonia was made using electrolysis and air separation at the hydro plant in Vemork in Norway. Read that again... most of Europe's ammonia, made from renewable energy before Haber in 1909. Cheap natural gas as a hydrogen source turned the tide soon thereafter. Coal also has been found to be a reliable hydrogen carrier. The good news is that hydro and even wind are making a comeback.

liveforphysics said:
Well, i guess if they've got a boat load of available energy, and dont mind a process that is going to be lucky to be 5-10% efficient with the use of the energy (energy into making NH3 vs potential energy return through combustion in an ICE), then its a win.

People that invest millions of dollars in projects like these aren't doing it because they have spare time and some random clean energy sources nearby that are going unused. They're doing it to make even more money... and natural gas' price volatility (along with any future carbon taxes or renewable incentives) makes renewable ammonia an interesting option, even if you just sell it for fertilizer. Have you done the efficiency calculations for the ammonia generation? What efficiency are we comparing to? The 5-10% seems pulled out of... somewhere.

Paul, I have plenty of references from conferences and some refereed articles if they would help. Let me know.
 
The road runner will be a dual fuel soon! I was thinking pure hydrogen because its simple and easy to make your self and can make up to 30% more power then gasoline with direct injection. I am interested in the Ammonia thing but have a lot to lern. There is more KW/h in 1 litre of ammonia then ! litre of pure liquid hydrogen!
 
NOx emmisions are never a good thing... unless you're trying to make a part car, part Nitric acid on wheels factory.

NOx is why our power plants have to use massive ammonia and urea scrubbers to neutralize the acids that form. The EPA doesnt even test the sulfur content.

You've got a lot to learn about how an engine works. Inherent to all engines is crevice volume area. Its the area local to the partially encloser surfaces of the combustion chamber that are imposssible to have complete combustion. In a hydrocarbon fueled engine, this is the reason for much of the various partially combusted hydrocarbon emmisions (one of the reasons we have to have cats etc). With ammonia, it means getting nitric acid (and other nastys) produced rather than partially burned HCs. Looking at the flash point and AF range, it naturally looks like a super PITA to get complete combustion with to begin with. I can understand why people bleed H2 in with it, or propane (or other hydrocarbons) to try to get acceptable/complete combustion properties. Just in this case, the partially burned parts make an engine eating nasty acid rather than HCs. To take advantage of the high anti-knock index, and try to make up for the low-ish eneegy content, the use of high compression ratios seems like a natural choice (much the same as methanol). In this case though, you cant bleed exhaust back through EGR to lower the N2 percentage (by increasing the amount of non-reactive CO2 in the chamber) and mitigate NOx production, because its exhaust is an increased source of Nitrogen. This pretty much leaves you with either running rich, and paying two taxes on fuel efficiency (latent heat of vaporization for fuel you cant completely oxidize, and hence additional NOx products, as well as the added fuel use), or urea/ammonia scrubbers and the added complexity and BS that goes along with them.

Can you tell me what Im seeing incorrectly?
 
If you dont like my 5-10% energy in vs energy out efficiency estimation, work your own numbers.

Energy as electricity used for splitting water into H2 (83%). Now throw away a 92KJ/mol as waste heat when you convert the higher energy H2 into NH3, and associated conversion pressures needed etc. Then logistics of getting it to the vehicle tank. Then burning it to convert from chemical potential to driving the wheels (or add more loss by going to electricity storage/controller/motor).

Do you think 10% is unreasonable? Show me your numbers.
 
liveforphysics said:
Can you tell me what Im seeing incorrectly?

In a word, "chemistry." Please reread my previous post. I'll repeat the key items here.

NOx emissions, should any exist after ammonia combustion, are neutralized by residual ammonia already in the exhaust stream (the best way to do it), or by ammonia leaked into the exhaust stream after the fact (harder to do correctly).

Let me repeat, a properly tuned ammonia engine will not exhaust more NOx than a gasoline engine. In fact, the ammonia provides a way to make even lower NOx emissions than a gasoline engine would itself provide. This is not a scrubbing operation. This is catalytic conversion of a mixed gas stream.

Wikipedia states it another way (emphasis mine):
Combustion
The combustion of ammonia to nitrogen and water is exothermic:
4 NH3 + 3 O2 → 2 N2 + 6 H2O (g) (ΔHºr = –1267.20 kJ/mol)
The standard enthalpy change of combustion, ΔHºc, expressed per mole of ammonia and with condensation of the water formed, is –382.81 kJ/mol. Dinitrogen is the thermodynamic product of combustion: all nitrogen oxides are unstable with respect to nitrogen and oxygen, which is the principle behind the catalytic converter. However, nitrogen oxides can be formed as kinetic products in the presence of appropriate catalysts, a reaction of great industrial importance in the production of nitric acid: ...

You really do need that catalyst to make ammonia go to NO. There is an intrinsic reaction temperature and kinetic pathway difference between the homogeneous (flame) combustion and heterogeneous (surface/catalytic) combustion of ammonia. In short, I mean that the surface reaction is much more controlled (fewer intermediates and side reactions) and may be better controlled to yield one preferred product over another by choosing catalyst type and reactant ratios appropriately. If we could make significant NO by burning ammonia in a flame, we would! It's much cheaper to have a torch than a precious metal like Pt supported on a ceramic. Nitric acid factory on wheels? If only it were so easy to make commercially valuable NO.

You seem to have accurately grasped a couple of things that I like to stress about the nature of ammonia combustion. First, partially cracking the ammonia or adding a combustion promoter to it in small amounts is done in order to get flame speed up, not to tune exhaust composition. Second, ammonia is indeed a high octane fuel just as is methanol, and the higher allowed compression ratios will garner more efficiency at the wheel.

As far as exhaust or pollution, you are focusing on a problem that doesn't exist. You haven't been around an ammonia engine before, so it's understandable that you might want to guess at exactly how combustion proceeds in the chamber and to worry that huge amounts of excess NO, NO2, N2O4, or whatever else might be formed. What isn't understandable is your claim that a NO/NO2 issue exists in an ammonia engine when you have zero experience with them.

And you don't need to take my word for it. The Hydrogen Engine Center, who made up the presentation I referenced in my last post, installed and ran an ammonia fuel-based irrigation engine in California which ran for almost a full year in 2008, constantly, during a demonstration project for ammonia fuel as a replacement for petro diesel. It was part of an effort by the California Air Resources Board to trim the CO2 pollution from agricultural applications. Some intermediate results are prepared here. The engine was tested not just for providing sufficient pump power but also for emissions, as the Board was very interested in those aspects as well. Tests (results on file with HEC) showed negligible NOx emission. And this is the standard of a state that requires all kinds of special emission equipment on regular cars.

Ted disassembled the engine block at the end of the project (late 2008) and found no abnormal wear.

If you'd like, I can put you in touch with Ted and you can discuss crevice areas or whatever else comes to mind. He has far more experience making engines run on alternative fuels than you or I ever will.

Again, the bottom line... these engines are being built and they run. They don't kill everyone nearby with a massive cloud of brown nitrogen dioxide. We have annual conferences where several groups will present their results on ammonia operation in spark and compression ignition engines, and occasionally gas turbines. This isn't a matter of which of us has the best hunch about what might possibly happen. It's already out there. I'd no sooner claim to you that light can't travel through a vacuum.

liveforphysics said:
If you dont like my 5-10% energy in vs energy out efficiency estimation, work your own numbers.

Easy, now. I don't like it when people throw numbers out there for no good reason (and neither should you). All I'll say is that it's likely that the "well to wheel" efficiency for ammonia and gasoline is likely quite close (per liter, slightly less so per kilogram). You will note that Paul was talking about fertilizer manufacture, rather than fuel. In that case, it'll be a $/ton of ammonia that is important, and with dominating dependence on electricity cost (which is regional).

You're a smart guy Luke, you know that in the past that I've respected your advice on electromechanics a great deal. Public discussion forums are a great place to learn and talk about ideas that are new, or at least new to some, but there's no need to try and be an expert in everything. Nobody here (or anywhere!) is.
 
Seems like it shouldn't be difficult or expensive to get a small used engine of an appropriate configuration, and then for an enthusiast to convert it to using ammonia for a fuel using that fuels most effective adaptations.

Regardless of the results, I am curious to see some real-world data from flogging a bench-mule...
 
There is already an established distribution system for liquid ammonia. Most propane companies also distribute it.
This has been a very interesting thread on alternate fuels
 
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