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Thoughts on Waste Plastics: A Valuable Fuel that Needs to be Utilized

Posted: December 4, 2014

Dr. Bill Lamont shares his thoughts on the potential for extracting energy from waste agricultural plastics.

Tell me what is wrong with this picture: Plastics are derived from natural gas or petroleum, are then processed into a usable and socially acceptable product that runs the gamut from the plastic drip irrigation tape or silage bags used by growers to the plastic wrapper from your Thomas’ English Muffins pack and the little plastic tab to millions of small plastic pill bottles. Each product still has most of the BTU’s of virgin petroleum or natural gas locked inside and may or may not be recycled and in many cases is buried in a landfill. Does this make any sense? Would you throw gasoline or fuel oil down into a landfill? That is what we are doing when we waste this valuable fuel (not trash) that is right here above ground waiting to be tapped.

Here at Penn State we have been dedicated to solving this problem which is indeed one of the world’s major environmental problems – what to do with the increasing volumes of plastic waste generated by the world population. Some of this is being recycled but much is still wasted in a landfill, or scattered over the landscape, or floating around the oceans of the world. You also must have noticed all the media attention about alternative fuels and energy sources, such as ethanol, biomass energy such as switch grass, wind and solar energy just to name a few that will help us pull ourselves out of the energy crisis that we have dug ourselves into. I am not speaking for or against these initiatives but why hasn’t the press or anyone else noticed the all low hanging fuel fruit lying around the environment worldwide just waiting to be harvested? The large consumer plastic waste stream is a potentially untapped fuel source and one that I am sure a company like Waste Management could build a pretty good positive public relations campaign around.

I want you each to think about all the plastic waste generated in your own households or farmsteads. What about the butter dish with the wider mouth than base or the plastic security package that the new tool you bought at Lowes came in. I had a friend in New Jersey who saved most of his non-recycled plastic waste and it was a real eye opener for him how much plastic he was wasting. I did some extrapolation to the state of New Jersey based on the number of households and the number of pounds wasted was considerable. Go back to your Thomas’ English Muffin pack and think how many of those are used in Pennsylvania and then the United State each day.

While there is strong demand for recycling PET plastics like soda bottles, what about garden garbage generated when you buy plants for the garden? This includes the plastic pot or plastic six-pack, and if you buy enough, it also includes a plastic tray or flat to hold the six-packs. You can reuse the pots yourself, of course, and sometimes garden clubs or conservatories need them for plant sales, but most recycling programs do not accept them.

The answer we believe whose time has come is recovering valuable energy from waste plastic by first densifying or shredding and chipping it thus making it easier to transport and then burning it at the high temperature of 2000 degrees F to capture the fuel value trapped inside.

Plastofuel™

A simple process was invented at Penn State in 1995 to densify waste plastics into a fuel nugget, called Plastofuel™. The process, developed in the Department of Agricultural and Biological Engineering, aims to reduce waste plastic buildup on farms around the world. It can also be used to recover the energy in non-recyclable plastics. It works by forcing film plastic items, rigid plastic items, or both, through heated dies, thus melting a thin jacket that encapsulates the pieces of plastic and dirt within the extruded material exiting the die. Sharp knives cut the extrudate into dense fuel nuggets that can be easily conveyed, stored and shipped. Plastofuel™ can be made either on the farm or in small industrial settings, thereby consuming the energy close to the source. The benefit of the system is that it converts an annoying waste into a valuable fuel, with a minimum of energy expended in the process. Non-recycled consumer plastic food and beverage containers can also be used in the process. Many of the plastics not currently recycled can be used a raw material for the Plastofuel™. The unit can be set up at county or regional recycling centers where waste, non-recyclable plastics can be turned into fuel.

A former Ph.D. graduate student Dr. Matt Lawrence who worked on the Plastofuel project with Jim Garthe is currently continuing to work on the project at Alfred State University, Alfred, NY. Matt is located in the Mechanical and Electrical Engineering Technology Office. His office phone number is 607-587-4652 and his e-mail is LawrenMJ@alfredstate.edu. He has a great team of students and colleagues collaborating on this project and I look forward to great results in the future. If his team can develop a machine that can burn the plastics and create electricity then the opportunities are unlimited for cleaning up the environment while harnessing the energy trapped inside the collected plastics.

With the spotlight on global warming and energy self-sufficiency, it makes sense to capture the energy contained in waste plastics that are made from natural gas or petroleum that has already been brought to the surface and made into useful products and can now be used again, reducing our dependence on outside sources of energy while cleaning up the environment.

The time has come. Please contact Matt if you are interested in leaning more about this exciting project or supporting his program or being a part of the program.