Plastofuel™ is a densification process for converting dirty plastics into a clean burning fuel. The process accepts both rigid and film plastics and forces them through a heated die, melting the outer layer of plastic which locks in dirt, debris and small pieces of plastic. By only melting the outer one to two millimeters of plastic, energy is conserved, especially when compared with the standard pelleting process which requires the entire mass of plastic to be melted. The extruded material, called extrudate, is then cut to any length desired with a hot knife, sealing the ends to make the nugget durable. The fuel nuggets can be blended with coal in coal-fired boilers, or someday burned in the GR Technologies burner described later.
The First Prototype
Shown in the next two photos is the first prototype machine operated by hydraulics. Notice dirty mulch film and drip irrigation tubing are hand fed into the hopper, where the red-colored hydraulic cylinder forces the material through the die (a pipe) that is heated with silver-colored electric band heaters. Note the extrudate peeking out of the die.
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The Second Prototype
A second, more sophisticated Plastofuel™ machine was designed as 
part of Matt Lawrence’s Ph.D. degree requirement, shown here. It uses an IQAN programmable logic controller to regulate the hydraulics which pre-compact items as large as nursery trays. Once densified to a specified limit, the hydraulics automatically force the plastic over a linear grid (sharp knives) and through a four-channel heated die. Hydraulically actuated hot knives cut the extrudate to any predetermined length. This is shown in the first photo below. In the second photo, without the cutoff knives in place the extrudate forms some shepherd’s crooks for the research team to use during Halloween dress-up, or maybe elsewhere, who knows.
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The Mobile Processing Unit
The latest Plastofuel™ machine is housed within a tandem axle, plastic-derived fuel mobile processing unit, shown below. An engine-generator provides electrical power for the hydraulic unit and the Plastofuel™ machine (not shown). The trailer and associated equipment were funded by an $87,000 Pennsylvania Department of Agriculture grant, which allows the unit to be demonstrated to the public or used at various research sites.
Burning Plastofuel™ with Coal
Making the fuel is one thing, burning it cleanly is another. In 2002, combustion tests were conducted in the combustion laboratory of Penn State’s Energy Institute. Plastic was blended 5 and 10 percent by calorific content with coal. Dirty mulch film and drip irrigation tape from three States was made into Plastofuel™. It was then sliced into small pieces (first photo), then burned with the coal in a stoker simulator (second photo). Air emissions and burn quality were closely monitored. Test results were encouraging. See the “Further Information” drop down menu (the last one) to view the test reports.
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