One of the most common statements I hear after posting a diary mentioning the use of ammonia as a fuel is that it’s far too hazardous for such duties. It’s important to remember that the Dutch ran their school buses on ammonia during World War II as an alternative to the unobtainable petroleum products and that with a little consideration ammonia can be used for all sorts of fueling operations, including home heating.
A few thoughts on the matter are below the fold.
Ammonia, chemical formula NH3, has, surprisingly enough, three hydrogen bonds. The natural gas we usually heat, formula CH4, with has four and there’s an added boost because the carbon atom forms a bond with two oxygen atoms as opposed to the ammonia’s nitrogen which just doubles up with another nitrogen atom. Ammonia bears about 40% of the energy of a comparable amount of fossil fuel.
The combustion products of a properly tuned ammonia flame are water and nitrogen. Make a mistake and you can get a bit of ammonia passing through and maybe some nitrogen/oxygen compounds. All but nitrous oxide are easily handled with a standard catalytic converter. There should be a study of this combustion but I’m confident the trace greenhouse gases, even though more potent, are a better choice than the flood of CO2 from fossil fuels.
Ammonia is an inhalation hazard. How in the world would we safely heat a home when a leak could be deadly? Easily done ... with a gadget like these.
Those are a line of seven Central Boiler outdoor boilers. Most are meant to take wood, a few of those are dual fuel with an option for oil to get the wood going, and I think the two at the far end might be corn/wood pellet units. The insurance companies love ‘em ... cause it gets the combustion outside the house. No house fires, no carbon monoxide poisoning, and if you’re running ammonia no inhalation hazard.
These are strange looking beasties to those who live in areas currently heated with natural gas. Go to New England and it is common to find a boiler driving heat exchangers rather than the forced air systems common to the rest of the country. If you needed to make one of these work with an existing furnace you’d run feed lines into the house, put a heat exchanger in line with your existing system, and there’d be some control work. Making them run right is an art, but it’s an art any HVAC man can learn in a season or two.
I think this will start in farm country first. Homes currently running on propane because they’re off the natural gas grid could end up with one of these ammonia nurse tanks parked next to a boiler as its fuel source instead.
I need some boilerplate of another sort when posting this, and it would be regarding methamphetamine. This dangerous, addictive drug is to rural areas what crack cocaine is to big cities, and anhydrous ammonia is one of the ingredients. This isn’t the 5% ammonia cleaning solution you get at the store, it’s the pure stuff, stored at 33 degrees below zero. We solve for this in a couple of ways: a little calcium nitrate in the ammonia which wrecks the reaction, there are marker dyes included that allow law enforcement to track down a person who has been handling the stuff in non-farm applications, and rural states long ago put ephedrine based decongestants behind the counter and started requiring signatures. Cutting off the most key precursor has dramatically reduced the number of meth labs found in rural areas.
This is what finding a meth lab looks like, in case you were curious. I was photographing the ghost train outside Superior, Iowa when I noticed a propane tank, tubing, and a hygrometer locked inside the abandoned caboose. I knew what it was right away and the Dickinson County sheriff’s department arrived promptly to begin investigating.
While on the subject it should be noted that in addition to heating one can also drive a backup generator using ammonia as a fuel. Here is the intake system for a Ford 300-6 rigged to run an ammonia/propane mix. The propane is needed because ammonia is darned hard to start on its own. When we do this on a large scale instead of a separate starter fuel the systems will just crack a bit of the ammonia, making hydrogen, which is a fine combustion accelerant.
OK, that’s the only world saving idea I came up with today. I’ll see if I can better it a bit tomorrow ...