Nikhil Patel is giddy with boyish enthusiasm as he describes the functioning of what is, essentially, a series of tubes at UND's Energy and Environmental Research Center.
In one end goes wood chips, garbage, tar-soaked railroad ties, lignite, grass, twigs, the meaty yuckiness that's left over from a poultry processing plant, and out the other end comes a substance not unlike natural gas.
The tricky thing is all that biomass varies in moisture, and moisture really messes up the even heating required in the gasification process, he said. The machine, which he helped design, would not only continually adjust the heat level to match the moisture level, but also make use of the moisture to create a cleaner burning gas, he said.
"This is not rocket science, this is more complex than rocket science," he quipped, adding he began his career in aerospace engineering and switched over to studying gasification. It's an odd connection, but, he noted, who understands combustion better than the people who design jet engines?
Military funding
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Funding for this project comes from the U.S. military, the nation's single biggest consumer of electricity, which has a great interest in ensuring the reliability of its power supply against threats such as blackouts, hurricanes, electrical grid congestion and, potentially, terrorists. But the EERC can also see applications in many industries with an organic waste problem - say the poultry industry or the potato-processing industry.
The machine was designed earlier for a big power project involving railroad ties and two 1-megawatt generators in Kamloops, B.C. The aim now is to make it feasible for smaller power plants, such as the 35- to 40-kilowatt internal combustion engine UND recently received from Cummins Power Generation in Minneapolis.
This is the key to distributed generation, the ability to generate electricity on-site rather than receiving it from a central power plant.
Side benefits
Biomass is a term that encompasses pretty much any kind of organic material, and water being essential to life, biomass often contains a lot of moisture. Moisture, however, absorbs heat, complicating the gasification process, which works through heating biomass at low temperatures in a low-oxygen environment. The point is to heat the material enough so it evaporates, but not so much that it burns and consumes itself, using up energy that otherwise could be released as gas.
For this reason, many gasification systems are limited to relatively dry biomass with no more than 10 percent to 15 percent moisture content, Patel said. EERC's system is able to, through a secret process, compensate for the moisture and convert much of it to hydrogen, a gas that can be used as fuel. The system can take biomass with as much as 50 percent moisture.
This has to do with not just how the machine is designed, he said, but also how it's operated, varying the speed at which biomass is fed into the gasifier, as well as the temperature and amount of oxygen.
The next step of the project is to convert an off-the-shelf engine to run on this hydrogen-enriched gas, which most internal combustion engines aren't designed to cope with, he said. The hydrogen burns too hot and fast, throwing off the timing of the strokes and causing engine knocking, he said.
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But modify the engine and you get another benefit: The hydrogen-enriched gas burns cleaner, eliminating many potential pollutants, such as nitrogen oxide and carbon monoxide. That means the engine wouldn't need a catalytic converter, saving money. In other words, water, a liability, has been turned into an asset.
The byproducts are useful, too. Clean water is one. Another is charred biomass, rich in potash, which could be mixed with soil to improve fertility. Potash, an ingredient in fertilizer, has gotten more expensive in recent years.
Patel said the project will take about a year to complete with the engines running a week or so at a time to gather data.
Reach Tran at (701) 780-1248; (800) 477-6572, ext. 248; or send e-mail to ttran@gfherald.com .
