Sam Haig, an IChemE member and Senior Engineer at Axion Consulting spoke at the 12th European Gasification Conference about new technologies in place to permit simpler recycling of plastic films and flexibles into fuels and other products.
Traditionally plastic bags and other low-grade plastic film products are not widely recycled, due to difficulties with handling and sorting — instead, many international policies have involved bans or charges for consumers.
Axion Consulting, a UK recycling specialist says that recovery of plastic films is still in the early stages of development, especially in comparison to recycling processes for dense rigid plastics such as polyethylene terephthalate (PET) used widely in the drinks industry. However, the group believes that new processing technologies may accelerate progress in the field.
Mr Haig said: “Plastic films are lightweight and 2D in shape and can easily get mixed into other recycling streams, such as paper, causing contamination.
“They also have a tendency to get trapped in recycling machinery requiring regular maintenance. As a result, plastic films have been excluded from most public household waste collection schemes around the world.
“However, a new generation of machinery uses a flow of air to help detect and remove around 95% of films from co-mingled kerbside waste collections. The process is likely to be more economical and efficient than current machine-based and hand-picking operations.
Importantly, the recycled films can be used for products including refuse sacks and signage for retailers.”
Haig continued: “Our analysis also suggests that it is now economically viable to convert low grade plastics into fuel. We studied five chemical engineering processes and concluded that three: fast pyrolysis; depolymerisation; and gasification with biological treatment provided significant financial returns over a ten year period.
“The more efficient sorting of films at recycling facilities and the conversion to fuels are clearly better solutions than disposal in landfills or by incineration. However, avoiding irresponsible disposal in the first place and increasing our efforts to re-use plastic films and bags should be the priority for everyone.”
Sam Haig was speaking at the 12th European Gasification Conference in Rotterdam, The Netherlands, 10–13 March 2014.