New generation PET recycling plants anlagen developed

Lower energy consumption for high quality recycled materials

We’re all familiar with the wining sound that deposit return machines make when empty PET bottles are sent to the collection bin after they have been scanned.  The empty bottle has gone, and the receipt entitles the customer to his deposit. But what happens to the bottles?

Recycling polyethylene terephthalate, commonly shortened to PET, is nothing new.
PET bottles offer many benefits in comparison with glass bottles from their break resistance and significantly lower weight through to their ecological efficiency.  As a result, most beverage bottles are made of PET nowadays, and the proportion is increasing.  And since their introduction, industry has been engaged in recycling used PET bottles.

Sikoplast GmbH is a pioneer in developing and constructing PET recycling equipment. For around 50 years, experts in Siegburg have been constructing high quality recycling equipment for use across the world, and Sikoplast has been manufacturing high performance and innovative PET recycling equipment for over 30 years.

Now, the company has set the first machine from a completely new generation running. The new equipment heralds two groundbreaking developments.  Firstly, the previously unavoidable deterioration in viscosity during the PET recycling process is avoided, and in one case viscosity even increased and the material was better preserved; secondly, drying and crystallisation need less energy than with earlier techniques.

This energy-saving and therefore environmentally friendly technology is the result of an ingenious move made by the experts at Sikoplast. Until now, PET for recycling was first crystallised and then dried.  Now, it is possible to carry out both processes at the same time.

In addition, the process produces a high quality PET granulate which can be re-used in the production of PET bottles; so true recycling and not downcycling.

Unique technology

First of all, the PET to be recycled is stored in an interim silo to guarantee even feed into the subsequent dryer unit.  During the first stage, the material is warmed in a contact dryer, crystallised and dried.  Once prepared in this way, the material passes to a second drying stage to reach an extremely low level of residual moisture before it progresses to the extruder.

The extruder catchment area is equipped with vacuums, which eliminate the molecularly bound water in the PET before the material can start to degrade to any extent. 

A second vacuum is needed on the extruder to maintain or decrease viscosity.  The extruder therefore has a decontamination area which is also under a vacuum to extract loose components, particularly water from the melt.  Only when the water is extracted can viscosity be increased.

The melt is filtered in a screen changer to remove any solid impurities.  To this is connected an under water granulator. This unit consists of a diverter valve, a granulate dryer and a water vat with an integrated heat exchanger.
This means the SIKOPLAST under water granulator guarantees even granulate geometry.

The particular construction of the under water granulator is another attraction because reusing the residual heat from the granulate means energy-saving inline crystallisation can be achieved.

The new PET recycling equipment, which is already in production with one customer, is designed to process 500 kilograms per hour. Sikoplast supplies various series of equipment with throughput of up to 1,000 kilograms per hour.
The equipment is compact and therefore space saving. The latest drive systems mean the equipment can be operated by one person.