In many industries, odors and volatile organic compounds (VOCs) pose a barrier to increasing the share of recycled plastics—particularly for use in higher-value products. However, this can be overcome: Zeppelin Systems’ Fresh-TEC® deodorization systems, which operate either continuously or intermittently, remove VOCs from tempered recyclate by means of air flushing. Special attention is paid to both process and energy efficiency.

The Fresh-TEC® deodorization systems remove volatile organic compounds from tempered recyclate by air flushing. By integrating heat recovery and harnessing process waste heat, they deliver substantial energy savings. Flow-simulation–optimized process control ensures maximally effective decontamination. The system is organized into three stages: heating, degassing, and cooling.

Preheating Prevents Deposit

The Fresh-TEC® process reliably removes even long-chain compounds. In continuous systems, the bulk material is preheated—using Zeppelin Systems’ patented cross-flow heat exchanger—before entering the silo. This prevents VOCs from condensing in the silo as oily deposits.

The system also accounts for the energy content of the preheated granulate (coming directly from the extruder). Thanks to the compact, highly efficient cross-flow heat exchanger, higher air velocities can be achieved over the granulate—compared to a fixed-bed silo—resulting in faster and more effective heat transfer during both heating and cooling.

Odor-Neutral Plastics Through Decontamination

Volatile organic compounds are removed from recycled plastics by a thermo-physical cleaning process. Discontinuous systems—ideal for small batch sizes or frequent color changes—provide a convenient entry point for producing odor-neutral plastics. However, continuously operating deodorization systems are significantly more energy-efficient.

Energy-Saving Cooling

Thermal insulation on all system components and heat recovery via recuperators (air-to-air heat exchangers) drastically reduce heat and energy losses. Waste heat—for example, from the degassing silo or the cooler—is routed back to the heaters. The result: energy and operating cost reductions of more than 30 %.

Homogeneous Mixing Without Additional Energy Input

In plastic production and recycling, process or feedstock variations can make it challenging to achieve consistently high product quality. Gravity mixers markedly improve end-product quality by processing large volumes with minimal recirculation into an extremely homogeneous blend—without any additional energy input. This not only saves time and energy but also reduces dust generation.