Posted by Greener Tomorrow on November 12th, 2010
In a few years, farmers who have battled weeds and wildflowers that were choking out their crops may actually be cultivating some of those pests - and those pests may be the answer to America’s dependence on foreign oil. Researchers at South Carolina State University recently got a provisional patent for their process of making hydrogen fuel from a combination of finely ground switchgrass and cow manure.
They worked with many inedible plants that grew wild, but eventually found the greatest success with switchgrass, said Dr. Kenneth Lewis, head of the College of Science, Mathematics and Engineering.
Switchgrass is a kind of broom straw that is drought resistant and grows freely all over the country with very little fertilizer needed, he said.
Dr. Joe Emily, who headed up the project, said researchers settled on switchgrass because it’s not used for food and it’s inexpensive. But he noted that any biological material - waste paper, plant material and the waste left behind by loggers - can be used to make fuel because it all has carbon and hydrogen in it.
Cow manure is being used because of the way bacteria in cows’ stomachs digest cellulose in plants, Emily said.
Mammals, including cows, cannot digest cellulose, he said. “Cows eat grass and that digestion takes place through the action of bacteria in the cows’ … different stomachs. As the grass is digested, different gas byproducts are produced, with methane occurring at the last stage.”
The bacteria in the cows’ stomachs make hydrogen before they make methane, so the scientists have worked to stop at the stage where hydrogen is produced, Emily said. That hydrogen is then used to power a fuel cell.
The researchers began their simulation of the process by grinding the switchgrass in a blender and adding the manure.
“We started manipulating temperature, pressure and some of the environmental factors of that mixture,” Emily said. “We started changing things, temperature, pressure, etc. that would favor the bacteria that produced hydrogen and suppress the bacteria that produced methane … now we get mainly hydrogen.”
The researchers presented their results at the National Hydrogen Conference last year. The hydrogen went through a fuel cell where electricity was produced and operated a small fan attached to the end of the cell.
Researchers at the university have also been working on biodiesel fuel since 2008, when they created the Center for Energy Studies with a $252,000 grant from the U.S. Department of Defense. But they believe that hydrogen may be the best fuel for the future, Lewis said.
It can be used to power everything from cars to homes, he said.
It can be used in combustion engines, or it can be fed into a fuel cell to generate electricity.
“It will operate anything that runs on electricity,” he said.
Lewis said hydrogen has absolutely no harmful byproducts and does not lead to global warming by producing carbon dioxide.
“With hydrogen, we are basically producing energy from waste material - from basically nothing, with little overhead, we’re producing a very valuable energy source that is … totally non-polluting. You burn hydrogen, you get energy and water,” he said.
Ethanol and diesel fuel can also be produced with plants, but they produce carbon dioxide and diesel also gives off soot and smoke, he said.
While hydrogen is flammable, the university has done some studies on how to use it and store it safely, Lewis said.
Researchers looked at how hydrogen can be stored in metal alloys. The idea was that the alloys would absorb the hydrogen like a sponge absorbs water. When the fuel is needed, the alloy would be heated, and the hydrogen would be released, Lewis said. As long as the metal is cold, the hydrogen stays locked up in it.
“That way, you wouldn’t have to carry around a big tank of hydrogen.”
Researchers are already producing biodiesel fuel from the university’s used kitchen oil. Researchers are looking at plants that can be used to make diesel.
While hydrogen fuel is made from plants with cellulose, plants that have oily berries or leaves can be used to make biodiesel fuel, Lewis said.
“We know we can use corn, soybeans, but we don’t want to do that,” Emily said. “The world is hungry, so we want to use non-edible things.”
Lewis said that there are many non-edible fruits and berries growing in South Carolina that can be used to make fuel. Plants like kudzu that have been considered pests in the past might be used to make fuel, he said.
“We’re looking for things … that are a headache and a pain, but we can put to some good use,” he said.
There are also all kinds of fruits produced by plants that people don’t eat, like holly berries.
For example, magnolia trees may be a good source of oil for biodiesel, according to Lewis.
“They have those big old leaves and they’re shiny,” he said. “That ‘shininess’ means they’re producing some kind of oil. My thinking is we can harvest a sufficient amount of leaves without harming the tree. … Usually, if you pick it early enough, the leaves will grow back as well. … We may also be able to harvest the fruit of the tree.”
Lewis applied for a grant to move the research to the farm level. He believes that farm could become self-sustaining.
“The farm could actually be sustained by this — the whole thing - all the electrical needs, heating needs and everything else, because you can burn hydrogen,” he said. “If you burn hydrogen, you get water, that’s the byproduct, which is nice and clean, or you can use the hydrogen to feed into a fuel cell to generate electricity.”
Source and Image: TheTandD.com
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