The CHISA conference I visited this August contained many lectures and posters contributing to Sustainable Development Goals. Here are my two highlights concerning waste polymer recycling:
Here I am at CHISA at the DEGruyter bookstand, holding my book, the second edition of product and process design
Waste polyolefins, polyethylene, and polypropylene, used in textiles, can be reused by extracting pigments using a solvent. Klimosek, et.al., of University Prague showed the technical and economical feasibility of this option by a process design, backed-up by laboratory scale experiments.
Boon and de Groot of University Twente presented a process design for converting waste PolyLactic Acid (PLA) into the monomer, followed by filtering off the non-PLA plastics using a centrifuge. The resulting clean monomer can then be polymerized again. The economics of the process show a pay-back time of one year. Lab scale experiments backed up this process design.
I highlight these two lectures because they are about complete process concept designs with recycle of solvents and also containing favourable economics. The approaches followed are more economically promising than polymer recycles based on pyrolysis followed by steam cracking and hydrogenation to monomers. The PLA recycle design by a simple hydrolysis to the monomer shows that this polymer can play a bigger role in a circular economy, than in the present linear economy.