Environment & Recycling
Looking for New ways of EPS recycling
Synbra Technology is always looking for novel ways of recycling and has participated in the 2003-2005 green loop recycling and is now investigating the 2014-2015 the polysolve process. For a summary refer to the section: From Creasolv to Polysolve
From Creasolv to Polysolve
In 2003 -2004 Fraunhofer Institute in Freising (BRD) carried out a “chemical” recycling project of EPS waste. Partners were: FIW, Joma, IsoBouw, Neue Herbold, DKR, Interseroh, E&E, MAKSC and Synbra. The German Government (Innonet) funded this recycling headed by the Fraunhofer Institute in Freising Germany.
The summary can be found here.: Green Loop EPS
A more detailed description on the on the Creasolv process Pilot plant for the Creasolv® Process
In cooperation with the Fraunhofer Institute IVV, CreaCycle GmbH developed the Creasolv® Process. This "selective extraction" is based on standard process technology (patented by Fraunhofer Institute).
Proprietary Creasolv® Formulations dissolve selectively the target polymer and the desired polymer precipitates when a special Creasolv® Precipitation Formulation is added after the cleaning from impurities.
Source from http://www.polysolve.eu/
For this undertaking a consortium was founded by five enterprises with a project budget of approximately € 1.000.000 in order to realize this ambitious goal and wherein all members brought in valuable key competencies:
Fraunhofer IVV & CreaCycle GmbH – Creasolv® Process
sat. Recyclingtechnik GmbH & Tulicon GmbH – Processing of waste plastics and separation of contaminated fractions
LÖMI GmbH – Recycling of solvents and polymer upgrading
After the process was optimized in phase 1 and in phase 2 the equipment capacity was provided for the pilot plant, actually in phase 3 (summer 2012) the sample production started with subsequent evaluation of the results.
In the course of the project international producers of electro and electronic equipment have been integrated and analyse the quality of the recycled plastics and assess their potential use in new equipment.
The completion of the project was planned for the beginning of 2013. To our current information it has not yet been created.
In 2005 Synbra considered building a Creasolv based pilot plant, but it was considered to be uneconomic at the time for the following reasons.
You can find the results of the evaluation in this Dutch document.
In summary it was concluded:
• Required was 3000 t/a of EPS, but most EPS is exported to China so: no guaranteed quantities.
• Transport with tankers with solvent, prohibitive high logistical cost
• Residual solvent, PS polymer had too high MFI
• Insufficient removal of HBCD, as tested in 2004 on Flame retarded EPS with HBCD.
• High investment in handling emissions.
However due to the now renamed Polysolve project developments undertaken by Fraunhofer current conditions may enable a commercial process in 2016/2017
• Transport Use single trip “pre cleaned” compacted EPS, It is envisaged that waste processor national collection points can be used.
• Residual solvent, The Process was improved to < 0, 02% solvent
• Sufficient removal of HBCD due to selective precipitation, Selectivity improved to < 1000 ppm, in the lab lower figures were realised.
• Recyclate Polystyrene: Quality PS Recyclate is now suitable for re use in PS application like XPS.
• High investment in handling emissions a Bromine recovery plant can deal with this, using existing infrastructure
In the Netherlands there is a possibility to use an existing a Bromine Recover Unit, which can handle bromine containing waste in its permit, and this plant has stringent solvent capture and adequate recycle systems.
In March 2015 Synbra Technology bv is in discussion with industry partners and stakeholders and is considering to support the start of a demo plant of 1000-3000 t/a, by using Fraunhofer Polysolve Technology.
However this can only be done if a legal framework is created under the BASEL Convention by embedding the technology in the relevant Technical Guidelines for POP's. Without such a legal framework the investment in recycling cannot be guaranteed.
What is Solvolyse
Process description: Solvolyse has the potential to recover base plastic and capture the non-desirable waste material. It is a thermo-chemical process leading to depolymerisation, using water under high temperature and pressure to transform composite waste. It dissolves polystyrene or plastics and the plastic additives remain as a solid which can be filtered and removed. This option has been investigated for plastics containing brominated flame retardants and different projects are at various stages of development.
Waste, after being subjected to preliminary shredding, is transported to reactors where it is dissolved in a specifically selected solvent and at a specific temperature. The Polystyrene solution in solvent of specific concentration is pumped, using a special pump for liquids of higher viscosity, through a system of filters with precision at approx. 250μm and 25μm. Mechanical impurities and modifying additives that cannot be dissolved in the applied solvent are separated by the filters. The used solvent is vaporized, and after being liquefied in a condenser it is again re-used in the dissolution process while the Polystyrene is extruded and cut into pellets. The HBCD, once separated, can be sent for bromine recovery with a yield of > 99%, encouraging the reuse of this valuable raw material.
Due to the molecular-level nature of this solvent-based recycling process it is possible to recycle the same sample of polystyrene hundreds of times over without causing significant deterioration in purity or quality.
Efficiency: In the example of HBCD containing Polystyrene foam, this method allows the recovery of approximately >99% of used flame-retardant additive.
Waste types: The solvolyse process can treat polystyrene and polycarbonate waste that contains HBCD and POP BDEs. It is expected to be a viable process for other POP containing wastes.
Pre-treatment: Before the polystyrene or polycarbonate material can be recycled, it must first undergo a pre-treatment process. This pre-treatment includes reducing the volume of PS foams (ref: PolySolve).
PolySolve: Solvent selection and synthesis
Our aim is to develop a reliable and robust process to accurately select and synthesise selective solvents for recovery of virgin grade polystyrene and polycarbonate from waste material. The solubility of polystyrene is known to be high in a range of relatively in volatile, non-flammable, biodegradable, sustainable and non-toxic solvents such as bio-derived aromatic esters. Polycarbonate may be solubilised by a number of environmentally friendly protic ionic liquids. Computer-aided molecular design will be harnessed to incorporate these properties along with selectivity for polystyrene (or polycarbonate) in the presence of co-formulated polymers, additives and other contaminants. The outcome will be a range of highly selective green solvents that can be adapted to recover polystyrene or polycarbonate from a wide range of products.
State of commercialization: This method is available on a pilot scale. Different projects are at various stages of development. Creasolv is based on a patent from Berlin and is designed for plastics containing brominated flame retardants. It is also suitable for other streams with a high removal efficiency of >99%-lab scale. PolySolve, developed in the UK mainly for engineering plastics recovery, is designed to deliver a modular, scalable process, centred on an environmentally friendly solvent-based system, to recycle (E)PS and separately Polycarbonate (PC) waste, at the molecular level, into a high purity product comparable to virgin material. The PolySolve project is supported by funding under the Seventh Framework Programme of the European Union (http://www.polysolve.eu/). Powergreen is a practical plastics recycling process which is already in place. Powergreen sp.. (LLC) has now also received funding from the European Commission to build a plant for 35000 mtons of PS foams in Poland, starting to build in 2014.
Caption : RESULTS on HBCD depletion in EPS
Rapid elimination of HBCD, by using a fresh SOLVENT in every step.
Extractive cleaning of EPS/XPS solution by precipitation.
Input ca. 10.000 ppm, target < 100 ppm → cleaning efficiency > 99,0% results so far varied between 50 and 100 ppm HBCD in the recovered PS.
Relatively large amount of SOLVENT usage → costs! Changing the process into counter flow will result in low solvent loss.
HBCD removal Results
X-ray fluorescence analysis (HBCD calculated via Br).
Conclusion is that HBCD can be very efficiently removed, due to solvent recycling. The range of residual HBCD was 50-837 ppm . In all case much less than 1000 ppm Br , which is confirming the results of another study where 773 ppm was detected (ref. paper_Littner PEP.pdf).
A road map as envisaged by Industry for the introduction of the Solvolyse process in a demo plant in the Netherlands is indicated in the Gantt chart.
- Recycling Magazin 20 /201, Oct 2010; Seiten 18-19; Siebenfache Effizienz - link
- Fraunhofer IVV 2011: Poly-Resource – High-quality injection plastic mouldings from shredder residues – link
- German Federal Ministry of Education and Research (BMBF) - "KMU innovative" Project Flyers, Status April 2012: Shredder-Residues as Source for Hidg-Quality Plastics (Poly-Resource) -link