28 Nov The Best Tyre Recycling Process: Does it Exist?
Much has been blogged about what the best tyre recycling method is. Many of my consultant friends and many technology providers have worked on the topic. I think there is not one “shoe-size” for everybody. The business objectives and the economic and ecologic environment are different for each venture looking at tyre recycling.
You might wonder first, what technologies are out there to take it up with post-consumer waste tyres which are designed to be indestructible. Well, apart from creative uses as fenders and gardening elements, I see three processes capable of dealing with the large volumes of tyres: Tyre pyrolysis, devulcanisation and micro-granulation.
What criteria might you look for when choosing a tyre recycling process? This will depend on where you are, what your tyre feedstock price is, what your local energy politics and pricing are and what your local customers could be for your products. I was recently asked by a consulting client to compare these processes and I showed them this table:
| Pyrolisis | Devulcanisation | Micro-granulation | |
|---|---|---|---|
| Material valorisation | Approximately 44% (carbon & steel) | Approximately 93% | Approximately 100% |
| Added value | Functional carbon products when post-treated; low PAH value | Simple “reclaim” not functional High quality material can have 70% retention of polymer properties | Non-functional economic filler, can slow tear propagation in tires |
| Commercially used in tires? | In OTR and PCR (Asia) | Reclaim used as oil replacement in OTR | In PCR, OTR and non-tire |
| Energy requirements | Low, pyrolysis is a net positive energy process | High, micro granulation needed for some processes before devulcanisation | High |
| Process technologies | Very high process complexity (pyrolysis, distillation of oils, upgrading of carbon products) | Chemical “reclaim (China, India), mechanical, biological… | Water jet, cryogenic milling |
And my summary was that while I think that there are great applications for micro-granulates and high quality devulcanised polymers, the tyre pyrolysis is the best process looking at the criteria in the above table. Yes, it is a very complex series (!) of processes. It likely will be a high investment project of 10-100m €. But it provides you the opportunity of running a net positive energy process which derives the energy from its tyre feedstock and on top produces more energy which you can feed into the grid. It also offers the opportunity to develop value adding products which already have found some inroads into the tyre industry. The tyre maker Bridgestone already has invested in tyre pyrolysis and many other top tyre companies are exploring the space.
(First published on Linkedin Pulse. Have a look at the comments!)