As I was digging out some large tree stumps with my backhoe, my thoughts migrated to what the early pioneers must have experienced in clearing land for farming. I reflected on the past – windmills or hand pumps used to move water, wood for fuel, candles or oil lamps for light, and horses and wagons to transport people and produce to market. Nowadays you’ll see wind turbines, solar panels, natural gas and nuclear generating electricity. Technology in the field of energy will continue to evolve and provide for our needs in our cities and on our farms.
I thought about the agricultural plastics that revolutionized the entire horticulture industry (particularly the vegetable industry) since the 1950s. Plastics are derived from petroleum or natural gas (the original “green energy”) – how might we use them as an energy source? Today, plastics certainly seem to be under attack, but it’s people that pollute that are the problem. What a waste of an energy-rich resource that has almost the same energy value as the petroleum or natural gas from which it originated. But recyclers tell me they can only get one to two cents per pound for agricultural film, and it costs them six to seven cents per pound to pick it up. What if we think about using it as a fuel to generate electricity on the farm?
When I arrived at Penn State in 1997, I was already interacting with a team headed by James Garthe, P.E., ag engineer and instructor the Department of Agricultural and Biological Engineering. He was researching the concept of using plastics waste as a fuel. Although efforts were focused on agricultural plastics (ag mulch film, drip tape, row covers, silage bags, trench covers, hay wraps, plastic twine, plastic trays, containers, etc.), we also recognized the large consumer plastic waste stream as a potential fuel source.
The team was contacted by GR Technologies Company Ltd., a South Korean company that had heard of the team’s research and said they had developed a high temperature combustion unit that was a hot water boiler heating system that burns pea-sized pellets made from waste mulch film plastic. The system preheats a series of combustion chambers to 1,650º – 2000º F for 10 to 15 minutes using fuel oil or kerosene, then automatically switches to the plastic pellets. We obtained a 396,850 Btu/hour unit for testing and burned plastics at the Horticulture Research Farm at Penn State. We demonstrated it to various interested groups at various venues. Of all the people that viewed, read about or attended presentations on the unit, we never had anyone say that what we were attempting to do made no sense but that it was indeed sorely needed.
A major question we wanted answered was what the air emissions from this unit was. We accomplished this by doing stack testing conforming to U.S. EPA standards conducted by an independent U.S. testing company in May 2005. The tests compared LDPE (#4) Korean pellets with granulated HDPE (#2) barrels, which had been discarded by a local firm. Three main groups of pollutants were analyzed: gases (sulfur dioxide, oxides of nitrogen, carbon monoxide and carbon dioxide), particulate matter and dioxins/furans. The test results proved that this is an extremely clean burning system in all three groups. The Pennsylvania Department of Environmental Protection reviewed the results, noting that combustion units with a heat input rating of 2.5 million Btu/hour or less are exempt from plan approval and operating permit requirements.
So where does that leave this alternative energy project? As team members retired, the project ended but the concept of using waste plastics as an energy source is still a viable idea. Recycling companies like R. Davis Enterprises Inc., Ag Plastics Solutions LLC and others believe that the unit could provide a way to deal with the ag plastics waste issue not only in the U.S. but overseas in countries with plastics disposal and energy problems.
I believe the South Korean unit was certainly a big step in the right direction, although it needs further engineering to refine the feed mechanism. Then there will be tests of the quality of and incorporation of new materials or components and attaching it to a boiler that will generate steam to run a turbine that can generate electricity. I favor electricity generation in which the unit burns 24/7/365 at approximately 2,000º so as not to have temperature fluctuation (as it is currently programmed into the burner to cycle on and off, needing more fuel to start up again). At roughly 30 pounds per hour of plastic needed to fuel the unit, that would be 720 pounds/day or 262,800 pounds/year for this size burner. The plastic fuels for the burner could be supplied by the recyclers and not be made into plastic pellets that the unit currently uses. Rigid plastics could be ground up and the film plastics shredded to be fed into the machine.
This is a potential alternative energy source that would go a long way to keeping plastic waste out of landfills and reduce open burning of plastics. Open burning at low temperatures is inviting dangerous pollution of the environment. I believe what is needed to move this technology onto the farm is an entrepreneur/visionary that can provide an infusion of capital, provide or hire engineering expertise to make additional modifications to the combustion unit and to couple it to a boiler that will generate electricity. We could potentially manufacture a new unit and work with recyclers to obtain a fuel of designated plastics that can be used in the burner. I firmly believe that if we can send folks into space, we should be able to make this happen and provide an alternative energy source for the farms in the future and at the same time reduce the waste of this valuable resource.
You can contact me with feedback on my columns or ideas for future columns at firstname.lastname@example.org.
Leave A Comment