In well documented experiments, Garthe co-fired these nuggets in boilers along with coal, at very high temperatures to generate heat for farmers' horticultural greenhouses.
He writes: "Combustion tests were conducted in 2002 at Penn State's Energy Institute. Discarded, soiled watermelon mulch film and drip irrigation tape from farms in California, Florida and Pennsylvania were made into fuel nuggets, then co-fired with coal in five and 10 percent quantities based on heat value. All testing conformed to US Environmental Protection Agency [EPA] standards.
"Regarding emissions, most of the tests conducted revealed that plastics indeed burn well with coal. Research on plastic-coal mixes has been done elsewhere in years past with good results. The presence of coal in the mix helps maintain the temperature of combustion around 1800-2200 degF, minimizing most emissions of concern. However, in the stoker simulator some of the samples were quite soiled, Florida in particular with sand, thus test results for dioxin emissions passed, but were disappointing. It is believed that the high ash content may have restricted air movement through the burn. The combustion team plans to continue testing in a full-scale unit soon to assure that emissions are in conformance with strict guidelines established by the US EPA."
Since then, interest in Plastofuel has grown. A South Korean firm has fabricated a burner that will combust Plastofuel directly, without any need to be mixed with coal. Patents have been filed for the process and research continues. Garthe says, nuggets maybe made in backyards or the production can be scaled up to industrial strength plants.
Markets for Plastofuel:
Sizable markets are emerging for Plastofuel and other plastic derived fuels [PDF]. Cement and steel majors are conducting trials using plastic waste as fuel adjunct, with a view to reduce energy costs. Cement giant LaFarge North America, Pa has begun trial burning waste plastic as a fuel supplement. These trials are being conducted with a close eye on emissions. The company is keeping local people informed and involved.