INNOVATION | ODOUR REDUCTION
distillation. Andrea Cabanes, working in the university’s Research Group in Waste Management, Energy, the Environment and Nanotechnology (REMAN), and Andrés Fullana, Professor in Chemi- cal Engineering, dedicated a year and a half to development of the technology which has been patented and was unveiled last year. Cabanes says: “This technology aims at achiev- ing a high quality of recyclate regarding contami- nants and odour, so that plastics from post-con- sumer sources can be used in high-grade applications, for example, for detergent bottles.” The process involves several stages: firstly, the
Above: The Department of Sensory Analytics at Fraunhofer IVV in Germany deals with the characterisa- tion and optimisation of plastics recyclates
Right: The University of Alicante in Spain has developed a technology for odour reduc- tion in recycled polyolefins based on steam distillation
pathways into the packaging waste and via the recycling process into the recyclate were identified. Depending on which process step cannot remove an odorant or even results in a new odorant, targeted measures can be taken to reduce odor- ants or avoid the formation of new odorants.” The Fraunhofer IVV scientists use a series of sensory analytical procedure to identify the odours. In the LDPE study, evaluation of the sample materi- als was first undertaken by a trained panel. The researchers then used chemo-analytical methods such as gas chromatography-olfactometry and two-dimensional coupling with mass spectrometry. They were able to determine the chemical structures and also possible formation pathways and sources of the odorants. “These key findings can now be used to develop customised solutions for optimisa- tion of the odour of plastic recyclates, starting at the waste collection stage,” says Fraunhofer IVV. The researchers also focused on the influence of the collection strategy on the sensory impairment of the waste. They found that the way the packaging waste is collected has a large bearing on the odour quality of plastic shopping bags. Fraunhofer IVV says: “There are significant benefits by separate collection in the yellow bag [as in Germany’s collection system]. Waste collected in this way had a significantly lower overall odour. In contrast, the waste fraction collected in the general household waste had more intense cheesy-like, sulphur-like, and faeces-like odours.” Household waste has a higher organic fraction than separate collection and this favours the formation of microbial degradation products. The study also demonstrated that washing post-con- sumer LDPE shopping bags from the separate collection at 60˚C led to fewer odours and a reduced overall odour than the unwashed bags. The University of Alicante in Spain, a partner in
the study, has developed a technology for odour reduction in recycled polyolefins based on steam
28 PLASTICS RECYCLING WORLD | May/June 2020
www.plasticsrecyclingworld.com
separation and conditioning of the plastic waste, followed by shredding and washing using a sur- factant and then rinsing. The material must then be mechanically dried before the deodorisation stage, which is carried out in a steam distillation column. In the recycling line configuration, the steam distillation equipment would normally operate before the melt filtration and extrusion stages, although operation after extrusion is an option, says Cabanes. She adds that installation before extrusion is advantageous because then the deodorisation eliminates perfumes that may be released from the plastics during the melting and which may cause irritation in a worker’s respiratory system. The team is currently working with partners to develop the technology further. Cabanes says: “At this moment we are working at a lab-scale with a capacity of 100 g/h approximately, and we are running some tests for companies interested in our technology. We see that before going to industrial scale, we need a transition in between and for that we will need to build a pilot plant of 10-20 kg/h to validate the technology on a larger scale. That is why now we are looking for private and public funding to do it.”
�
IMAGE: FRAUNHOFER IVV
IMAGE: UNIVERSITY OF ALICANTE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48
