PET chemical recycling

PET Recycling (chemical process)

In view of the ever increasing use of PET for softdrink bottles of various colors and other liquid flasques, the content of which requires a blocking layer (milk, beer), the chemical recycling will be of major importance in the future. Officine Costarelli commercializes a cost-effective chemical process (patent registered) which recuperates the basic ingredients of PET, Terephtalic Acid and Ethyleneglycole, in a pure chemical condition.

The process offers the following advantages to the clients:

Economically very competitive process. For a plant size of 10,000 t/year the chemical processing cost is estimated at 500 $/t, due to the low-cost additives and low energy consumption
No previous cleaning or selection of the material according to color is necessary
No removal of PE-taps or PE-labels required
Bottles with blocking layer can be treated without problems
The process can either produce the intermediate product PHT (Polyhydroxyethylterephtalate), which is used directly for new PET, or PTA (Terephtalic Acid) and EG (Ethyleneglycole) which can be sold directly to chemical industry or specialized producers
Existing conventional PET-recycling plant can be retrofitted for chemical recycling

Description of the Process:

The numbers follow the Flowchart

For viewing the flowchart you need the Plug-in WHIP!-Plug-in. You can download the Program free-of-charge from Autodesk under http://www.autodesk.com/whip . After download you must restart Windows.

1.Shredding and Washing	2.Separation of PE/PP and Drying of the Flakes

The material is transported to the washing plant ML1400, which simultaneously washes and shreds the material to flakes. Paper labels are removed in the process	PE/PP are eliminated in a Sink-float tank and the the flakes are dried and additionally cleaned in a centrifuge. The ML1400 and the Dynamic Centrifuge have their own water circuit

3. Heating by means of Extrusion and Addition of the Reaction Additive	4. Addition of extra Ethyleneglycole

The material is heated in a special Extruder VULCANO 270-100 and the reacting ingredient is added. The PET-molecular chain is broken up and a water soluble substance is produced	Because of the difference in binding value to the molecular-chain of PET extra Ethyleneglycole is added in a closed loop. The resulting product is dissolved in distilled water

5. Separation of the non reacting plastic material	6. Separation reaction of Terephtalic Acid

The non reacting plasic materials are separated from the fluid solution and can be treated in a different process	The reacting additive causes the chemical separation of the Terephtalic Acid from Ethylenglycole. The Terephtalic Acid binds itself with the reacting additive

7. Filtering and washing of the Acid Substances	8. Drying and 9. Storage of the Terephtalic Acid

By adding of a strong acid the Terephtalic Acid is set free, the reacting additive joins with the acid, both pof which are recuperated. This process is done in a centrifuge with special filters	The recuperation and drying/cristallization of the Terephtalic Acid is done n a microwave furnace. Subsequently it is stocked in silos for delivery

10. Recuperation of Ethyleneglycole and 12. Storage of Ethyleneglycole	Final products Terephtalic Acid and Ethyleneglycole

The solution of Ethyleneglycole with water is distilled and the recuperated liquid Ethyleneglycole is stored for delivery	The two basic ingredients of PET, Terephtalic Acid (70-73%) and Ethyleneglycole (27-30%) are thus recuperated in technical pure condition.

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