As project coordinator, TWI is leading a consortium of 10 partner companies working on the ISOPREP project, offering an innovative new approach to recycling of end-of-life, complex multilateral products, such as waste carpet. The process combines mechanical and chemical recycling, to obtain virgin like polypropylene, all in a cost effective manner.
A specially designed mechanical recycling unit isolates the PP fibres at high yields and purity. The fibres are then processed further, using a technique that has been newly developed within the consortium, successfully removing pigments, additives and colourants.
We spoke with TWI senior project leader, George Theodosopoulos to find out more about ISOPREP and how it can help manage waste materials and provide a route to recycling polypropylene.
Firstly, George, can you start by introducing yourself?
I joined TWI’s polymer and composite technology (PCT) group two years ago and, with a master’s degree in polymer science and applications and a PhD in macromolecular chemistry, was stationed in the novel polymer technology (NPT) section of the group.
Within NPT we research, provide consultation and drive innovation on polymer related themes. These include material selection, the lifecycle management of plastics, failure investigations, polymer ageing and polymer welding. Within our plastics lifecycle management portfolio we manage a number of projects focused on plastics recycling and the implementation of circular economic strategies, ISOPREP is one of them.
What are the goals of the ISOPREP Project and why is this work important?
ISOPREP is an EU funded project that is focused on eliminating the problem of polypropylene carpet waste accumulation. The goal is to recycle PP from waste carpet in an efficient and cost effective way. Our target is our pilot plant to recycle 1 tonne of carpet waste into virgin-like PP and, through the results of LCA, be able to scale up and prove the benefits of the technology.
The whole process is circular and all chemicals and mediums are recycled and reused, responsibly managing waste materials and by-products.
The reclaimed PP is of high quality and can be reused with great confidence in performance and reliability.
To guarantee product homogeneity and the safety of our employees, procedures are in place, guaranteeing employee safety against biohazardous materials, establishing material homogeneity and material ageing, and PP quality is assessed before processing.
The work has been focussed on the recycling of carpet waste stock, why was this chosen as a focus, and also, what other potential applications are there for this process?
Carpet is difficult to recycle, it is a multi-material product containing other polymers and textiles other than PP. This project sets the barrier and is the first step towards the recycling of multi-material and composite products.
Also, as a product, a known range of PP grades are used and, in its end of life, can be easily separated from the waste stream. This limits contamination from other polyolefin grades or materials. Furthermore, carpet, in its lifetime, does not see much environmental exposure, which causes material degradation, hence recycled material properties and performance can be guaranteed.
What have been the challenges with the project?
There have been many challenges, however this is expected from a project like this.
Many technologies and techniques are involved, requiring specially designed equipment while always bearing in mind processing cost, material quality, health and safety and environmental impacts. The first major challenge we had to face was the change in the previously selected ionic liquid due to the increase in precursor costs. The IL is of paramount importance since it is used in the chemical recycling step of the process and is responsible for the eclectic dissolution of the PP materials. Other challenges include required changes in the design to ensure handler safety, such as explosion proof equipment, and those targeted to minimise energy requirements, whilst meeting the desired processing speed and mass balance.
Also, strategic decisions needed to be made to ensure project delivery on-time and within budget. Fortunately we were able to prevail and overcome technical and other difficulties.
How have TWI helped to develop the project?
TWI has great experience in the management and delivery of innovative and research projects, with an extensive track record of successful projects. We have a team of experienced innovation managers as well as technical experts in the field. We have a good understanding of the requirement and, most importantly, in risk identification and risk management.
At TWI one can find technical experts in almost every field and enjoy the support of highly qualified employees.
What are the next steps for the project?
Next steps include system optimisation and improvement; at the moment we have built the mechanical recycling unit and are currently building our larger chemical recycling plant.
This technology has great potential and we believe that it can be applied to other waste streams and help to transition plastic products in a truly circular economic model.