Monster Machines: The Fuel Cell That Runs On Corn Husks And Old Bullets

The Iowa Army Ammunition Plant (IAAAP) in Middletown, Iowa, has an overabundance of two things: corn waste and excess energetics -- leftover explosives, propellants, pyrotechnics and such. But using a new ethanol-based fuel cell developed by nanoMaterials Discovery Corp (nMDC) will transform these waste materials into clean, cheap, electricity. Two birds, one catalytic reaction.

Commissioned by the Armament Research, Development and Engineering centre at Picatinny Arsenal in New Jersey, the prototype fuel cell is designed to produce 10kW of power (and 2MW within five years) using ethanol as an energy source and nitramine-based ordinance. Corn ethanol is a renewable biofuel that is derived from corn stock -- either the kernels themselves or the cellulosic components like the husks and cobs -- and produced just like consumable alcohol is: use enzymes to break down the long carbohydrate chains into short sugars, ferment the sugars into alcohol, and distill. And with Iowa being one of the top corn-producing regions on Earth, there's plenty of waste available for precursor processing. The nitramine catalyst comes from waste energetics left over from the factory's production of medium and large ordnance, ie tank and artillery shells. Normally this is hazardous waste and expensive to dispose of properly but, as a catalyst, provides the shot needed to begin the energy production process.

"During the ammunition manufacturing process there is always an energetic waste stream that is generated, and that has to be taken care of somehow," explains Brian Meierdiercks, a Program Management Engineer with the Program Executive Office for Ammunition's Project Director Joint Services. "A lot of times its run through filters and the energetics are removed from the water. The fuel cell technology is actually able to take that energetic waste stream, run it through the fuel cell, and break down the energetic to provide additional power alongside the ethanol. Currently we have to pay either to have a system onsite, or pay someone off site to remove the energetic from the waste stream. So that's one cost we could avoid."

The fuel cell, known as the NDCPower fuel cell works as such, according to nMDC website:

The NDCPower fuel cell process technology relies on a new class of alkaline fuel cells that utilise primary alcohols as anode fuels. NDCPower alkaline fuel cells operate at over 50% faradaic efficiency and produce carboxylic acids in quantitative yield. Ethanol, Methanol, or syngas-derived mixed alcohol blends provide optimal precursor feedstocks. Formic and acetic acids are the main constituents of the corresponding product stream, and will be sold as industrial commodity chemicals. EOS fuel cells do not cleave carbon-carbon bonds and do not produce CO2.

More impressively, the catalytic process can be performed at room temperature, so there is very little risk of the nitramine explosives going boom. What's more, the process yields inert gases that can be used to make a variety of industrial chemicals that can then be sold to further recoup operating costs.

"Depending on how you operate the fuel cell, you can produce different byproducts, such as potassium acetate, which is used for de-icing aeroplanes and runways," said Meierdiercks. "The fuel cell technology would allow us to power ourselves separate from the electrical grid, which could be subject to storm damage or something like that, so we can continue to operate off of local power," he continued. So between the below-market-rate power generated by the cell, the disposal cost savings of the nitramine, ande the sale of useful chems, the Iowa facility stands to save about $US1 million per year. Not a bad return on a bunch of stuff that would otherwise end up in landfills and hazmat sites. [Cleantechnica, US Army, NDC Power]

Pictures: Iamnao/Shutterstock, US Army