Ammonia

From Energy-Experts

See article in Wikipedia based on this, which will be more up to date: http://en.wikipedia.org/wiki/Ammonia#Fuel

Since coming across the fact that the 60 MW hydro station at Vermork, Norway provided most of Europe's ammonia fertilizer,from 1911 onwards and during the '30s, by electrolysis of water, to hydrogen, and then synthesis from hydrogen plus air to ammonia, I have been following up the ammonia as a vehicle fuel, which I had previously ignored - several people have previously mentioned it. The potential attractions are large: Upside

• It can apparently be burnt in modern high speed car engines with little modification, other than the addition of 5% pilot fuel - which could be hydrocarbon or hydrogen, of which the latter could be stored on board. I am still looking for a good scientific reference for this though.
• It is compressible / liquefiable / dense enough to fit into existing cars.
• You would get all the Jeremy Clarkson benefits of manly, noisy piston engines compared to the pathetic non manly whine of a motor.
• you wouldn't encounter the opposition from the motor trade who want to carry on flogging expensive to maintain IC engines.
• At the moment the ammonia price is about the same or less per unit energy than petrol
• No greenhouse emissions
• Less toxic and flammable etc.
• Huge manufacturing infrastructure exists based on natural gas, but only the front end needs to change.
• Huge distribution infrastructure already existing
• Could be produced using electricity from renewable and fluctuating wind power.
• Could be produced in the middle of say the Gobi desert / Sahara wind / CSP farm and shipped ot eg Europe
• Can readily be used in modern engines unlike methanol and will not damage seals and pumps
• batter powered cars will require some form of stored fuel to heat the occupants whereas as ammonia means we could carry on using the existing CHP method.

Downside:

• As Mark Barrett points out, the efficiency will be less than a battery at 70%. It seems that ammonia can be burnt at around 40
• It can be electrolysed at say 70% efficiency and burnt in a car at around 40% (I await a reference) given 28% overall, which is half that of a battery.

However, if the 30% waste heat can be used in say district heating this ups the effective efficiency. Also as I understand it / assume / recall from school days, , the electrolysis of water not only gives hydrogen, but also oxygen - this is normally produced at huge energy cost from the air using electricity - so presumably there are offset energy efficiencies there. Does anyone know the energy balance for producing ammonia from electricity, and the offset oxygen production cost, and at what temperature the waste heat is available at? Any one got any other comments / references. Apparently it was used to run busses in Belgium in WW2 but I can find no references for that. David Andrews

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From: Dave EU Andrews [1] Sent: 08 June 2008 09:38 To: 'info@NH3car.com' Subject: Ammonia may be not such a daft idea after all. http://www.memagazine.org/contents/current/webonly/webex710.html The present disadvantage is that pure ammonia is not suitable for use in high-speed engines. Its flame speed is too low.

However, ammonia can be doped by environmentally friendly chemical additives, and thus be compatible in high-speed engines.

http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/28890yy.pdf - this appears to show that the efficiency is around 50%...... but that is probably LCV so may be nearer 40%.... Still not bad. Also says: Ammonia is comparable to gasoline as a fuel for combustion engines. Three gallons of ammonia is equivalent to one gallon of gasoline in energy content. In other terms, 2.35 pounds of ammonia is equivalent to one pound of gasoline in energy content. Cost wise in 1998, bulk ammonia was $1.13 per gallon gasoline equivalent. http://www.allbusiness.com/services/business-services/3913748-1.htmlTed Hollinger's presentation was one of the highlights of the conference. If the Hydrogen Engine Center ammonia fueled commercial internal combustion engines are as high in efficiency (50%) as Ted Hollinger indicates, it will be difficult for fuel cells to compete," commented Norm Olsen, P.E., Manager of Iowa State University's BECON (Biomass Energy Conversion) Facility in Nevada, IA. http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=553368Ammonia fuel: the key to hydrogen-based transportation MacKenzie, J.J. Avery, W.H. World Resources Inst., Washington, DC;

Abstract Ammonia (NH3) is a high octane fuel (110) that can replace CO2 producing fuels in automobile transportation. It shares with hydrogen the virtue of yielding only water and nitrogen as combustion products when burned in internal combustion engines but avoids the packaging, safety and logistic problems of using hydrogen fuels in motor vehicles. Ammonia can be stored under moderate pressure at ambient temperatures. (Its physical properties are closely similar to those of liquid propane.) It can be packaged in a volume compatible with present automobiles. It is used as a fertilizer in quantities of over 100 million tons per year so that facilities for its storage, safe handling, transportation and distribution are available worldwide. It could be an economical replacement for gasoline if the foreseen costs of air pollution and global warming caused by fossil fuels are included in the economic evaluation http://www.memagazine.org/contents/current/webonly/webex710.html

Abstract : Ammonia can be used successfully as a spark ignition engine fuel and at presently existing compression ratios, if introduced as a vapor and if first partly dissociated to hydrogen and nitrogen. Under such circumstances little engine modification is necessary other than a means for flow control of the ammonia and adjustment of the spark timing. Maximum experimental power output for ammonia was 72 per cent of that for iso-octane. This result compares favorably with a theoretically predicted output, when adjusted for 5 per cent hydrogen dissociation, of 75 per cent. Specific fuel consumption using ammonia is increased by a factor of 2 over that of hydrocarbon when compared at peak power and 2-1/2 times when compared at maximum economy. Hydrogen concentration in the fuel feed is a critical factor for successful operation on ammonia as fuel. Minimum concentrations appear to be 4 to 5 per cent by weight at intermediate engine speeds of 1800 rpm. Engine performance rapidly falls if less than minimum concentrations of hydrogen are used. This seems to relate to the self-generating character of the ammonia decomposition during the compression and combustion processes. Performance factors such as are influenced by engine speed, spark timing and manifold pressure are not far different with ammonia than with hydrocarbons as long as minimum amounts of hydrogen are inducted as a part of the fuel flow. (Author) Descriptors : *AMMONIA, FUELS, INTERNAL COMBUSTION ENGINES, PERFORMANCE(ENGINEERING), SPARK IGNITION, EXPERIMENTAL DATA, POWER,

FUEL CONSUMPTION, GRAPHICS

This is a very good Summary and covers many of the obvous questins, costs toxicity etc - from http://www.energy.iastate.edu/Renewable/ammonia/ammonia/2007/Olson2_NH3.pdf