Plastics Recycling

Deodorization in Plastics Recycling: An End to Unpleasant Odors

Improving the Odor of Post-Consumer Plastic Recyclates

The demand for plastic recyclates from post-consumer waste is growing. However, unpleasant odors are often a challenge. Removing them is a prerequisite if plastic recyclates from post-consumer waste are to be used for the manufacture of new products.

The recyclate must meet high standards not only mechanically, but also in terms of sensory properties. However, plastic recyclate from post-consumer waste frequently exhibits unpleasant odors.

Coperion and Herbold Meckesheim offer a variety of solutions all along the recycling process to remove unpleasant odors from plastic. These technologies excel due to their especially reliable and energy-efficient operation.

Deodorization technologies all along the recycling process

Coperion and Herbold Meckesheim Technologies for Deodorization in Plastics Recycling
  • Mechanical Pretreatment I Silo Degassing
    Herbold Meckesheim Washing Line

    In a first step, odors are eliminated as the waste plastic undergoes mechanical pretreatment during shredding, washing and drying. Further odors can be removed from the shredded plastic in a silo using fresh air circulation.

  • Devolatilization in the ZSK Recycling Extruder
    Coperion ZSK Recycling Extruder

    The next, intensive devolatilization step, which markedly improves the recompound’s sensory quality, takes place during compounding in a ZSK twin screw extruder.


    Following melting and intensive homogenization of the waste plastic in the ZSK extruder’s process section, volatile particles are degassed from the plastic melt in a highly energy efficient process. Using various technologies such vacuum devolatilizations, these dissolved gases are reliably removed from the product. This effect can be significantly intensified with the addition of liquid stripping agents.


    Use of a ZS-EG side devolatilization unit provides a particularly effective and stable degassing process in the ZSK twin screw extruder, maximizing its deodorizing capabilities when high quantities of gas are present. 

  • Degassing recycled plastic compounds
    Coperion Mobil Deodorization Unit Front

    Coperion also offers post extrusion and pelletizing deodorization systems that play a further key role in improving waste plastic to the qualitative level of new plastic. They reliably remove any residual unpleasant odors from recycled plastic compounds. Hot air flows through the pellets in silos, diffusing even particularly stubborn, long-chain molecules from the compounds. For this step, Coperion has developed two different process solutions, depending upon the desired end product quality, the temperature it requires, residence time and quantity of air. 


    One method uses two silos – one to warm and deodorize the granulate and another to cool the granulate with cold air. In this process, comparatively little energy is needed to warm the product to the desired devolatilization temperature. Moreover, the cooler’s process heat can be used to pre-warm the pellets, increasing energy efficiency. 


    Alternatively, warming, degassing and cooling can take place in one silo by using two Bulk-X-Change heat exchangers. This solution is much more compact, requiring only one silo.

Coperion and Herbold Meckesheim

Coperion and Herbold Meckesheim


Our experts help you to identify the optimal degassing methods for your recycling process.

The focus is always on product quality, investment and subsequent operational costs. A variety of technologies are at your disposal in Coperion and Herbold Meckesheim Test Centers worldwide to test potential deodorization methods in advance.

Advantages at A Glance

Versatile scope of application for recyclate and highest product quality
Highly efficient Coperion and Herbold Meckesheim solutions with maximum throughputs and reliability
Optimal solution for your application, taking investment and operating costs into account
Low maintenance and operating costs
Test Centers for recycling applications and mobile deodorization unit for tests at your location

Comprehensive product range

Coperion Plastics Recycling - ZSK Extruder

ZSK Recycling Extruders and Side Degassing Unit ZS-EG

Coperion’s ZSK Recycling Extruders are suitable for intensive devolatilization of the melt. Volatile substances in small or large quantities can be reliably removed.

In some cases the devolatilization performance capability with conventional top vent extruder barrels can be limited. In this case the ZS-EG twin screw side devolatilization unit provides the solution.

Coperion Plastics Recycling - Odor Reduction

Silo Degassing

Coperion offers different solutions for deodorization along the plastics recycling process. Odors can be removed from shredded plastic in a silo using fresh air circulation.

In addition Coperion offers post extrusion and pelletizing deodorization systems that play a further key role in improving waste plastic to the qualitative level of new plastic. 

Coperion Consulting

Global Service

Our service structure consists of over 350 service engineers and technicians around the globe who not only look after your machines and systems but also after your business. They see themselves as partners who secure your future.


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