WEST LAFAYETTE, Ind. - A group of scientists have created a portable refinery that efficiently converts food, paper and plastic trash into electricity. The machine, designed for the U.S. military, would allow soldiers in the field to convert waste into power and could have widespread civilian applications in the future.
"This is a very promising technology," said Michael Ladisch, the professor of agricultural and biological engineering at Purdue University who leads the project. "In a very short time it should be ready for use in the military, and I think it could be used outside the military shortly thereafter."
The "tactical biorefinery" processes several kinds of waste at once, which it converts into fuel via two parallel processes. The system then burns the different fuels in a diesel engine to power a generator. Ladisch said the machine's ability to burn multiple fuels at once, along with its mobility, make it unique.
Roughly the size a small moving van, the biorefinery could alleviate the expense and potential danger associated with transporting waste and fuel. Also, by eliminating garbage remnants - known in the military as a unit's "signature" - it could protect the unit's security by destroying clues that such refuse could provide to enemies.
It has a favorable ratio of energy inputs to energy outputs. But that does not tell us what fraction of the energy in the waste material gets converted into electric energy.
Researchers tested the first tactical biorefinery prototype in November and found that it produced approximately 90 percent more energy than it consumed, said Jerry Warner, founder of Defense Life Sciences LLC, a private company working with Purdue researchers on the project. He said the results were better than expected.
The U.S. Army subsequently commissioned the biorefinery upon completion of a functional prototype, and the machine is being considered for future Army development.
It reduces waste volume by a ratio of 30 to 1. But the article provides no indication of production costs. It starts up running on diesel fuel until its processing apparatus starts producing burnable fuel. At that point the fuel it produces powers continued processing to make more fuel. But most of the fuel produced is usable for other purposes.
If the refinery can be made cheaply enough it could provide supplementary power for a number of uses.
The refinery also could provide supplementary power for factories, restaurants or stores, Ladisch said.
"At any place with a fair amount of food and scrap waste the biorefinery could help reduce electricity costs, and you might even be able to produce some surplus energy to put back on the electrical grid," he said.
Much of the fuel the system combusts is carbon-neutral, said Nathan Mosier, a Purdue professor of agricultural and biological engineering involved in the project.
So what would this unit cost to mass produce and operate? If the waste was free from trash collection then what would the cost be per kilowatt-hour? A much larger unit would probably have lower labor costs per kwh. Also, the portability could be sacrificed for lower operating costs.
|Share |||Randall Parker, 2007 February 03 02:29 PM Energy Biomass|