Materials go full circle with plastofuels

ROCK SPRINGS, Pa. – Plasticulture’s uses don’t stop in the high tunnel at Penn State University.
Researchers here are looking at ways to complete plastic’s lifecycle and are experimenting with plastic-fueled power.
“We want to use the plastic one more time, to close the loop and capture energy one more time,” said Bill Lamont, assistant director at the Center for Plasticulture at Penn State.
Great need. For all industries, more than 100 billion pounds of plastics are manufactured every year, Lamont said. Agricultural uses scoop up almost 83 million tons of that.
“Agriculture is just a small segment. Plastics are used from the beginning all the way to the outgoing products,” Lamont said, pointing out plastic trays used to hold nursery flowers, plastic crates used to gather produce, and packaging in grocery stores holding berries and other fruits.
But not all of that can be recycled into things like plastic lumber because it’s dirty or doesn’t fit into a processor’s system.
The other option is high-temperature combustion, and a prototype burner from Korea is used at Penn State.
How it works. In high-temperature combustion, leftover plastics on the farm – filthy mulch and row covers and spent high tunnel covers – are melted into tiny nuggets, called plastofuels, according to Jim Garthe, a Penn State ag engineer.
First, kerosene or fuel oil preheats a combustion chamber, then the plastofuels take over. The nuggets are burned with coal in boilers at 2,000 degrees.
Those plastofuels have three to four times the heat value of household trash, and fall just short of the BTUs produced by diesel fuel, he said.
The boiler heats water that can then be used to heat the ground and interior of high tunnels to mimic spring or fall temperatures year-round.
Burning clean. The pellets go from solid to molten to gas and into a flame inside the burner, and are a clean-burning fuel, Garthe said.
The Penn State researchers are looking for funding for federal emissions tests, and believe the burner will pass the Environmental Protection Agency’s standards.
“You generally can’t think of plastic as a fuel. This is really a fascinating system,” Garthe said.
“We need to keep consumer plastics out of landfills and inside the consumer stream.
“We can use one person’s waste to heat another’s high tunnel. Then we can recycle that high tunnel into the next generation,” Garthe said.
(Reporter Andrea Myers welcomes reader feedback by phone at 1-800-837-3419, ext. 22, or by e-mail at amyers@farmanddairy.com.)