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Recently the South Koreans invented a car that runs on an 70% ammonia 30% gasoline fuel mix. (link) In America we already have instituted policies that require refueling stations to mix Ethanol produced from corn stills with gasoline to extend our fuel supply.

My question is, if you added a ammonia to an ethanol/gasoline fuel mix, would it cause a reaction? If not, would it still burn and be able to be used as fuel?

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  • $\begingroup$ It wouldn't react, and I guess it could be used, but don't see much sense in adding ammonia. $\endgroup$ – Mithoron Mar 9 '17 at 0:28
  • $\begingroup$ Also, the US rule is that in the winter gasoline must contain 2.7 wt/wt% oxygenated fuels as ethanol, where several different oxygenates are allowed. Technically, a fuel pump that says something like "Contains 15% ethanol" may actually have little to no ethanol and use ethers like ETBE instead (MTBE has mostly been banned, but used to compose 95% of California's oxygenates, which were frequently reported as ethanol). $\endgroup$ – airhuff Mar 9 '17 at 0:38
  • $\begingroup$ Would be concerned at the increased risk of generating nitrogen oxides which are already a problem in atmospheric pollution in cities $\endgroup$ – Waylander Mar 9 '17 at 10:49
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A fuel that is mostly ammonia is an altogether different fuel formulation that would not reap the benefits of the oxygenated fuels program in the US for gasoline. In other words, there would be no reason to mix in ethanol or any of the other approved oxygenated species used in gasoline (the specification requires 1.5% - 3.5% oxygen by weight during the winter (state dependent) and is reported as ethanol, regardless of the oxygenated species actually used).

According to this US Environmental Protection Agency document:

Oxygenates are fuel additives that contain oxygen, usually in the form of alcohol or ether. Oxygenates can enhance fuel combustion and thereby reduce exhaust emissions. Some oxygenates also boost gasoline octane. The Clean Air Act requires use of oxygenated gasoline in areas where winter time carbon monoxide levels exceed federal air quality standards. Without oxygenated gasoline, carbon monoxide emissions from gasoline-fueled vehicles tend to increase in cold weather. Winter oxygenated gasoline programs are implemented by the states.

The octane levels of ammonia fuels are already very high at around 120. There would seem to be little benefit in the form of carbon monoxide emission reductions by adding oxygenated hydrocarbons to a fuel that is 70% ammonia.

So, the bottom line is that there is no reason to expect ethanol and ammonia to be in the same fuel formulation. Furthermore, if there were ethanol in the ammonia based fuel, there is no reason to expect the two to react in any significant way.

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I'm glad to know people are still reading my old article about the South Korean AmVeh car!

No, ammonia wouldn't react with gasoline or ethanol, as far as I'm aware. Yes, it would burn as a fuel. Ammonia is hard to combust, so to reap the benefits of its high 120 octane rating, you'd need to make certain engine adjustments. Also, you'd need to make sure no copper/zinc/brass alloys were in use anywhere the ammonia is - it'll corrode those very quickly and that would not be good.

Using ammonia as a drop-in fuel is a totally different idea to using ethanol as a drop-in fuel. Different motivations, different results. The idea with ammonia is that, if/when produced from renewable feedstock, it is a carbon-free, energy-dense liquid fuel. If you don't think carbon is a problem, you won't think ammonia fuel is a good idea.

For actual engine performance using a gasoline-ethanol-ammonia blend, see this presentation: https://nh3fuel.files.wordpress.com/2014/10/nh3fa-2014-shehan-haputhanthri_1.pdf. See pages 13 and on: dynamometer tests demonstrating horsepower/RPM for various % ethanol blends; note the ethanol is used here as an emulsifier as well as a fuel, to stabilize the gasoline-ammonia blend. The same team of researchers at Texas Tech have published other work on the subject but I don't have my hands on their most recent publications, although I know they've continued to develop the work.

Regarding NOx emissions, ammonia is the reagent used in most SCR clean-up systems, so it's an onboard solution to its own problem, just takes a bit of engineering design to address.

For those interested, the actual application of ammonia as a fuel is more likely to begin in stationary generation (and certainly not in the US). Here's an article I wrote earlier this week regarding two utility-scale demonstrations of low(er)-carbon power generation in Japan: both employ ammonia in a dual-fuel combustion process, one in a coal plant the other in a natural gas plant: http://www.ammoniaenergy.org/industrial-demonstrations-of-ammonia-fuel-in-japan/

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