Enterprise Europe Network

Removal of odours in recycled plastics

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Partner keyword: 
Plant Design and Maintenance
Plastic bags
Plastics, Polymers
Recycling, Recovery
Other industrial machinery for textile, paper & other industries
Chemical and solid material recycling
Other pollution and recycling related
Other research and experimental development on natural sciences and engineering
Tertiary education


A Spanish university has developed a procedure for the elimination of odours in recycled plastics by steam stripping. This process, which comprises several stages, can be applied to plastics of different nature, improving the quality of the recycled plastics and increasing their reuse as raw material for products for later use. Companies interested in the commercial exploitation of this technology through licence agreements and/or technical cooperation are sought.



The organic compounds that cause the bad smell of recycled plastics are found both inside the polymer matrix and on the surface of the plastic. In order to increase the quality of recycled plastics, a Spanish research group has developed a procedure and a system to eliminate these odours by extracting VOCs with water vapour.

This solution is based on the fact that extraction with steam favours the internal diffusion of volatile compounds due to the working temperature, as well as decreases the boiling point of volatile organic compounds immiscible with water, increasing their evaporation from the polymer surface to the gas phase and consequent removal.

The procedure for the elimination of odours in recycled plastics comprises the following stages and equipment (Figure 1):

a) Separation of recycled plastic material (P-VOCs) in an identification separation plant;
(b) Shredding of the plastic and reduction of the size of the plastic particles;
(c) Chemical washing of shredded plastic with surfactant in a stirring tank;
(d) Rinsing of the plastic material to remove dirt and chemicals used in stage (c);
(e) Drying of the rinsed material in a mechanical dryer;
(f) Deodorising the dry plastic material in a deodorising module where:
- the plastic material is introduced at the top of a distillation column;
- the steam from a boiler enters through the lower side of the distillation column;
- the plastic material falls by gravity along the distillation column, the plastic material comes into contact with the steam and the organic components are extracted from the plastic material by steam stripping;
- there is an outlet of organic product, comprising water vapour and VOCs, at the top side of the distillation column; and
- the VOC-free plastic exits at the bottom of the distillation column.

Apart from obtaining a clean product that is a plastic free of VOCs and odours (PL) that is reusable for other uses, it ends up generating an organic product (PO) that is also reusable, where there is water (FO-2) that can be used externally for other uses, and can also be reused to be recirculated to the boiler; and where there are organic (FO-1) remains composed essentially of essential oils that can be commercialized or reused as fuel for producing steam.

This process can be applied to plastics of varied nature (polyethylene, polypropylene, polyester, etc.) from plastic waste of both industrial or domestic origin. Therefore, this procedure could be useful in the plastic recycling sector or manufacturers of plastic containers as an initial stage to ensure the quality of the raw material.

The research group is mainly looking for companies interested in acquiring this technology for its commercial exploitation through license agreement. The company should be responsible for the development of the industrial prototype, the validation of the technology, its installation and its introduction into the market. The university will be ready to provide technical assistance in each step, if required.

However, the research group would be also interested in establishing technical cooperation agreements to further develop the laboratory-scale prototype, to find new applications or to adapt it to the company’s needs. The goal of this type of collaboration would be increasing the technology readiness level for a future commercial exploitation of the patent. The university would offer its support based on their know-how; while, the partner sought would provide its expertise to help improve this invention. The university would offer this partner a preferential option to acquire this technology in exclusivity.

Advantages & innovations

Cooperation plus value: 
The main innovative aspect of this invention is the removal of odours in recycled plastic by steam stripping. By means of this process that removes the odours in plastics originating from domestic and industrial sources, it is possible to solve the issues of conventional washing and increase the application of these plastics as raw materials in the polymers industry. This technology has the following advantages: - The result is a clean product that is a plastic free of VOCs and odours with an increased quality in comparison with the recycled plastics obtained by conventional recycling. - By increasing the quality of recycled plastic, new opportunities can appear in the market for this type of plastic (e.g., packaging in the cosmetics and hygiene sector). - Fully efficient and environment-friendly procedure. - It boosts the reduction of plastics in landfills. - It reduces the production costs in the industries of the sector compared to other technologies such as supercritical CO2 extraction. - The deodorization module is a hermetically closed circuit that allows heat recovery. - The deodorisation stage can be carried out before or after extrusion. - The deodorization module can act as an independent module of the recycling process. In this case, pellets recycled by other companies are fed into the system for removing malodours and improving the quality of the material. - The organic phase obtained consists of essential oils (e.g., limonene or pinene) that can be marketed or reused as fuel for steam generation.

Stage of development

Cooperation stage dev stage: 
Under development/lab tested

Partner sought

Cooperation area: 
- Type of partner sought: Industry. - Specific area of activity of the partner: Recycling of plastic waste; Manufacturers of plastic containers; Producers of virgin raw material. - Task to be performed: * In the license agreement: to buy a license for the technology, to further develop it to the industrial scale and to introduce it into the market. * In the technical cooperation agreement: to provide their expertise in order to collaborate with the scientists on further development and improvements of the technology. The company should identify technical requirements and/or market and client’s needs in order to carry out further technical development so that the market readiness will be increased and the technology could be commercially exploited.

Type and size

Cooperation task: 
SME 11-50,>500 MNE,251-500,SME 51-250,>500