Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - DEVULC (Novel Devulcanization Machine for Industrial and Tyre Rubber Recycling)

Teaser

The objective of the DEVULC project is to develop a new devulcanisation technology that leads to an efficient and environmental sustainable recycling of rubber goods. Rubber material are very complex compounds which consists of entanglements of long polymeric organic macro...

Summary

The objective of the DEVULC project is to develop a new devulcanisation technology that leads to an efficient and environmental sustainable recycling of rubber goods. Rubber material are very complex compounds which consists of entanglements of long polymeric organic macro molecules linked together by sulfur bridges. The chemical reaction between sulphur (or another “vulcanisation agent”) and the rubber molecules network is called “vulcanisation” and is known to be irreversible, which lead to rubber recycling issues.
DEVULC devulcanization consists in reactive extrusion assisted by super critical carbon dioxide. This technology selectively breaks sulfur bonds while retaining the majority of carbon-carbon bonds, which enables the reuse of devulcanised compounds as raw second-hand materials.
The DEVULC project aims at engineering, manufacturing and optimizing a prototype devulcanisation unit and then scale it up to an industrial unit. Particular attention will be paid on deeply characterize devulcanised products and on the opportunity to mix recycled rubber with thermoplastics (TPV) for the invention of new materials.

Work performed

The first months of the project were allocated to the careful choice of the different component of the first devulcanization unit. 27mm twin-screw extruder has been chosen to be the core of the prototype. The different parts of the prototype have been assembled and installed inside Phenix facilities and this first unit has been led to proper functioning over these months of work. This devulcanisation unit is now able to run different kind of rubber; going from natural rubber (polyisoprene) to EPDM or GTR (Ground Tyre Rubber). Physico-chemical behavior of the recycled rubber.

During the second part of the project, our work was particularly focused on the TPV line. We ordered it in mid-2016 and we received it at the beginning of the year 2017. The TPV extruder have been installed inside Phénix facilities and we had to make some arrangements inside our warehouse. First TPV trials were conducted in this new line and led us to good products according to the mechanical properties we obtained.

In parallel, we took advantage of the extruder to simulate the devulcanisation process in order to prevent from troubles we might encountered. Infact, the TPV study subcontracted by Inspiralia is having delays and we need this study to begin the TPV study at semi-industrial scale. The extruder was available, that is the reason we had the opportunity to proceed to the devulc process scaling-up. To prepare this study we made some modifications on the new extruder: we changed the screw configuration and we worked without the die and scCO2. This study led us to good results for the devulc products quality. Unfortunately, we had to face some issues concerning the security and the products packaging. However, this study was investigated in order to prevent a part of the troubles we could meet when we will work on the industrial pilot extruder, in view to save time when we will scale up at industrial dimension. We understood then that the devulcanisation at bigger scale needs to be more secured to protect from hazardous gas emission and smelling. Additionally, we had to solve a problem about the packaging at the end of the devulcanisation. We found a solution to be able to pack the rubber continuously after the devulcanisation process in order to save space on the packaging, leading us to save money on transports.

Final results

Our recycled product are suitable to use as good quality raw material, in brand-new rubber formulation or reincorporated into virgin rubber or thermoplastic compounds. Numerous rubber compounding companies are interested in using our recycled rubber or buy the devulcanization system, which would lead to more sustainable management of rubber waste (especially by addressing end-of-life tire issues).
A significant benefit of our product is that the devulcanised rubber is not dependent of the oil price, unlike the raw rubber. By purchasing our devulc materials, customers can be sure that the price stay steady over time.

Website & more info

More info: http://www.phenix-technologies.eu/.