PETrecycling CZ is non-commercial, independent, free & unsponsored Czech web portal for funs, communities, administrative, law-makers, politicians, PET plastic industry etc. in the Czech Republic.

My closing statement read: "There is only one real effective and incentive method to encourage environmentally sound collecting of beverage one-way containers and it is deposit in combination with High-Tech R&D resulted Reverse Vending Machines!

Performance up, investment down

New, patented recycling technology increases plant capacity and reduces labour costs, investment costs and operating costs

February 6, 2004
EREMA, Ansfelden/Linz; Austria

With the recent and successful launch of its new "T-DD" technology the innovative Ansfelden-based company – world market leader for plastic recycling plants – has achieved a significant development in its internationally acclaimed plastic recycling process.

With the new technology (also called "Erema 4th Generation System") the dream of feeding very big portions discontinuously has – in the case of many plastic waste materials – come true.
But that´s not all: with this new technology the icing on the user´s cake is an increase in performance of up to 15% with no change in plant size (may even permit you to down one plant size with reduced investment), plus savings in specific energy consumption (energy consumption per kg of repellets produced) of up to 20%.

T-DD: Separation of material pre-treatment and extruder feeding

These results have been made possible by separating the working steps "material processing" (shredding, drying, agglomerating, preheating) from the step "extruder feeding" by means of technical modifications to Erema´s cutter/compactor. As is generally known, in the past the two working steps were integrated in one single process.

By uncoupling material pre-treatment from extruder feeding Erema has succeeded in shielding the extruder and its sensitive feeding/intake zone from throughput and quality-reducing feeding influences caused by - for example - moisture and moisture fluctuations, differing density ratios in the feedstock, very big feed portions, temperature inhomogenities in the feed material etc.
The result is an extremely uniformly fed and evenly operated recycling extruder which constantly performs at its best, regardless of virtually any detrimental factors as mentioned previously.

The T-DD System can also be retrofitted (within limits) to existing plants. This may make sense for applications where plant throughput has in the past been restricted by one or more of the above feeding factors.
According to the experience of customers so far, the accumulated production throughput (repellets produced over days and weeks) of classic Erema recycling systems featuring the T-DD upgrade is increased by up to 15%. This shows how worthwhile the modification is.

And there is a pleasant side effect: the average melt temperature inside the extruder falls when this new technology is used - despite capacity increasing. This is achieved through the extruder being fed with evenly preheated material; as a rule this allows deeper cut extruder screws with lower localised thermal peak load and friction. The result: reduced loss of the processed polymer and higher quality recycled material.

T-DD: Fascinating individual processing benefits

In some specific applications such as the processing of BOPET film waste, the new system delivers extraordinary benefits:

Here the new technology means that thanks to the defined time and reliable and therefore improved predrying of the feed material upstream of extruder feeding, there is no need for (what used to be indispensable) extruder degassing any more.
This is the exact equivalent of improved pellet quality; it is well-known that small amounts of PET melt dwell for lengthy periods (and without control) especially in the degassing domes of a conventional PET recycling extruder, only to return at some point in the extruder. It has been proved that such "contaminants" which are changed thermally, chemically and physically (IV) as a result of long dwell time at high temperature in vacuum are the cause of the undesired and previously inexplicable formation of "fish eyes" and inhomogenities (danger of tearing!) in BOPET film when high quantities of repellets are used for the production of the film.
First customer applications show that when using the new T-DD technology (without vents on the extruder) the share of repellets – depending on the application – can increase up to double that of what was previously possible, without any significant increase in fish eyes and film tearing at the main plant!

Additionally vacuum pumps are no longer required; this means lower operating and maintenance costs. The waste water problem with vacuum pumps is likewise no longer an issue.

Thanks to the extruder being considerably shorter (L/D ratio reduced by almost half) the user has a specific saving in energy in the region of 20 to 30% compared with the old degassing extruder PET processing technology; a much smaller main extruder drive can now be chosen whereas extruder output remains the same. With a medium plant size (700 kg/h, 5000 tonnes per year) and current average Central European (or Asian) energy costs per kilowatt hour, for example, the operator´s electricity bill can as a result be reduced by up to an impressive 40,000 euros per year!
All in all the T-DD technology used in BOPET recycling represents a considerable increase in the overall cost efficiency of the recycling plant for the operator.

But what happens to PET oligomers and monomers which were previously extracted by the extruder degassing? This is a question frequently asked by customers who are interested in the new technology. Here it can be said that as a rule merely a minor percentage of these "disturbing factors" can be removed by degassing, only for them to reform immediately in the downstream extruder section on the classic degassing extruder if only very minor traces of water are present. And minor traces of water are practically inevitable whenever hygroscopic PET is processed.
The fact is, in the PET repellets produced on the new Erema T-DD plant technology the amount of monomers and oligomers is not higher than in repellets produced on classic degassing extruders. However, repellets coming from Erema T-DD plants contain significantly less gel, and this is precisely what has always spoiled things for main-line operators in the past.


Contact:

Dort Christina
Marketing Assistent
EREMA Engineering Recycling Maschinen und Anlagen GesmbH
Tel.: +43 732 3190-105
Fax: +43 732 3190-6305
ch.dort@erema.at
http://www.erema.at