Circular Process for Disposal of Polyethylene Waste Plastic Films Through Pyrolysis
Abstract:
The sustainable disposal of waste plastic films from food packing is a problem that has long plagued the plastics industry. Many have tried to incorporate plastic film into recycling processes to support circular economies but have fallen short due to economic constraints or concerns over yield quality. A current solution is to convert this plastic into oils and fuels; however, this fails to create a fully circular economy for the continued use of plastic.
The proposed designed process addresses this challenge while also solving the need for economic viability and full circularity of existing plastics. With pyrolysis, waste polyethylene plastic film is broken down into light-hydrocarbons and converted into mono ethylene glycol of 99.9 mol% purity. Ethylene glycol is used to produce PET plastic, thus creating a fully circular economy.
The system consists of three main reactors – a fluidized bed pyrolysis reactor, fluidized bed ethylene oxide reactor, and CSTR ethylene glycol reactor – and various intermediate stages of distillation. The pyrolysis unit is maintained at 800˚C and atmospheric pressure to increase selectively towards the production of ethylene over lighter hydrocarbons.
The internal production of steam and fuel gases helps reduce overall operating costs and increase production's financial feasibility. Few waste streams are created due to the focus on reuse of material wherever possible, subsequently also decreasing the impacts on the surrounding environment. The designed plant is profitable in its first year of operation and has a payback period of less than five years, making this process a viable solution for plastic film recycling
Students:
Katherine O'Hare, Abby Maves, Samantha Goertz, Alida Teodorescu
