Recycling and crystallization of PET
The use of PET is growing in all the markets around the world, particularly in the production of bottles.
The enormous quantity of material derived from wasted bottles, was reused, especially in Asian countries, for many industrial applications as the production of textile fibres.
These countries have large recycling plants suitable to work for several tonnes per hours. These kind of plants are very expensive as initial investment, and either as operating cost.
The lack of small shredding and washing plants, more economical and profitable, has always slowed the recycling by the end users, which was forced to buy virgin materials or, where possible, acquiring material regenerated in granules.
Some local manufacturers of washing plants, started the production of plants for medium and small capacity ranging from 200 to 1,000 kg/h. In this way, with a reasonable investment, it is possible for end users, grind and wash their own material at low cost, which after CRYSTALLIZATION can be extruded to produce, thermoforming sheets, tubes, profiles, monofilament for brooms and brushes, or injected to produce household items, technical articles, garden furniture and everything else we can achieve with PET.
Starting from the fact that PET requires a process of crystallization before being reused, in the last years the request for crystallization plants increased significantly.
In the past were mainly manufacturers of extrusion or washing plants to require this type of machinery, which today represent a primary need for the end-user as well.
The crystallization process allow the transforming of PET from an amorphous to a crystalline state. In this way PET re-acquires its basic feature before being subjected to a new transformation process.
Grinded or flaked PET, after washing, is subject to a new drying stage, and then through a series of steps process which lasts around half an hour, it is heated from ambient temperature to a temperature not less than 140°C. As nearer it comes to the material plasticizing temperature, more efficient is considered the process.
The material thereby obtained may be either sent directly to the extruder in the case of production of the granule, while it needs to be further de-humidified in case of production of finished manufactured goods (sheets, monofilaments or any other extruded product).
The CRISTALLIZZAZIONE of grinded PET coming from thermoforming sheet but mostly from bottles, is a complex process.
The granulate is not uniform and flakes have a very small thickness. This does not allow an effective flow of hot air, and then there is the risk that bringing this product to the maximum tolerable temperature will trigger off an agglomeration process or even start to melt.
To prevent such a risk, it is essential to keep moving the mass without mixing it, and then evenly invested with the hot processing air.
Our CRYISTALLIZATOR differs from that of any of our competitors precisely for the diffusion system of the hot air in the material, which is not propelled by fixed diffuser, but spread through hollow reels which ensure a uniform temperature, even in the case of dusty materials or finely grinded, avoiding any clogging of the diffuser mesh and greatly simplifying the cleaning process in colours changing.
The advantage is that there is no need that the product, which have to be crystallized, has to has special features or that need to be mixed with virgin pellets material to prevent any agglomeration phenomenon.
While the scrap material from thermoforming process needs only to be grinded and do not require any preliminary washing, it is however particularly dusty. This dust, as well as triggering the agglomeration process at lower temperature, is also liable to colour change, tending to yellow, with negative consequences for the aesthetic of manufactured obtained with the reclaimed material.
In order to prevent these problems, a de-dusting system has also been included in the same crystallization plant. Air is blown by means of an organ pipe system at the top of the crystallizator where the material is still relatively cold. The dust is conveyed upward, where it is sucked into a filter and then collected. Due to the fact that greater speed of air blowing gives greater dust reduction and higher sieve grading, it is thus possible to establish the de-dusting degree required.
When a product does not require any special aesthetic characteristics, such as in the case of certain types of sheet used in building field, it is not necessary an intensive de-dusting.
Since 1996 Dega started the production of Crystallization machine but it is in recent years, due to the increasing in the consumption of PET, that the interest in this machine is growing continuously in the domestic market and international markets as well.
Dega has also become specialized in electronic systems and has succeeded in optimizing the starting point of crystallization process, being aware that any lack of precision in this phase cannot be offset in the subsequent processing stages.
There is a special microprocessor control which helps to reach the first crystallization process starting point. Afterwards, the process continues automatically with heating proceeding at constant temperature, which varies according to each specific type of material.
The processed material falls onto a valve and, after passing through a screw feeder, stored in a big bag, or moved to a dehumidifier or directly to the extruder.
Substantial energy savings are possible by undertaking the Crystallization, De-humidification and extrusion processes in sequence. In fact, as the product is already at the temperature of 160°C, due to the Crystallization, it requires a small amount of energy to reach the dehumidifier temperature of 180°C, and subsequent plasticizing into the extruder, which means that the Crystallization process does not add any further costs to the process of recycling.
In order to meet specific request from the market, in addition to crystallization plants, Dega is able to guarantee its customer a fully comprehensive supply, including washing system built by other companies as well, thereby acting as a main contractor.
Our standard range includes machines with an output from 200 up to 1,000 kg/h but we also realized a unit that reaches up to 3,000 kg/h.
Our main customers are manufacturers of sheets and monofilament, but we have also many customers involved in injection or in blow-moulding as well.
DEGA – Your partner in plastic processing
The enormous quantity of material derived from wasted bottles, was reused, especially in Asian countries, for many industrial applications as the production of textile fibres.
These countries have large recycling plants suitable to work for several tonnes per hours. These kind of plants are very expensive as initial investment, and either as operating cost.
The lack of small shredding and washing plants, more economical and profitable, has always slowed the recycling by the end users, which was forced to buy virgin materials or, where possible, acquiring material regenerated in granules.
Some local manufacturers of washing plants, started the production of plants for medium and small capacity ranging from 200 to 1,000 kg/h. In this way, with a reasonable investment, it is possible for end users, grind and wash their own material at low cost, which after CRYSTALLIZATION can be extruded to produce, thermoforming sheets, tubes, profiles, monofilament for brooms and brushes, or injected to produce household items, technical articles, garden furniture and everything else we can achieve with PET.
Starting from the fact that PET requires a process of crystallization before being reused, in the last years the request for crystallization plants increased significantly.
In the past were mainly manufacturers of extrusion or washing plants to require this type of machinery, which today represent a primary need for the end-user as well.
The crystallization process allow the transforming of PET from an amorphous to a crystalline state. In this way PET re-acquires its basic feature before being subjected to a new transformation process.
Grinded or flaked PET, after washing, is subject to a new drying stage, and then through a series of steps process which lasts around half an hour, it is heated from ambient temperature to a temperature not less than 140°C. As nearer it comes to the material plasticizing temperature, more efficient is considered the process.
The material thereby obtained may be either sent directly to the extruder in the case of production of the granule, while it needs to be further de-humidified in case of production of finished manufactured goods (sheets, monofilaments or any other extruded product).
The CRISTALLIZZAZIONE of grinded PET coming from thermoforming sheet but mostly from bottles, is a complex process.
The granulate is not uniform and flakes have a very small thickness. This does not allow an effective flow of hot air, and then there is the risk that bringing this product to the maximum tolerable temperature will trigger off an agglomeration process or even start to melt.
To prevent such a risk, it is essential to keep moving the mass without mixing it, and then evenly invested with the hot processing air.
Our CRYISTALLIZATOR differs from that of any of our competitors precisely for the diffusion system of the hot air in the material, which is not propelled by fixed diffuser, but spread through hollow reels which ensure a uniform temperature, even in the case of dusty materials or finely grinded, avoiding any clogging of the diffuser mesh and greatly simplifying the cleaning process in colours changing.
The advantage is that there is no need that the product, which have to be crystallized, has to has special features or that need to be mixed with virgin pellets material to prevent any agglomeration phenomenon.
While the scrap material from thermoforming process needs only to be grinded and do not require any preliminary washing, it is however particularly dusty. This dust, as well as triggering the agglomeration process at lower temperature, is also liable to colour change, tending to yellow, with negative consequences for the aesthetic of manufactured obtained with the reclaimed material.
In order to prevent these problems, a de-dusting system has also been included in the same crystallization plant. Air is blown by means of an organ pipe system at the top of the crystallizator where the material is still relatively cold. The dust is conveyed upward, where it is sucked into a filter and then collected. Due to the fact that greater speed of air blowing gives greater dust reduction and higher sieve grading, it is thus possible to establish the de-dusting degree required.
When a product does not require any special aesthetic characteristics, such as in the case of certain types of sheet used in building field, it is not necessary an intensive de-dusting.
Since 1996 Dega started the production of Crystallization machine but it is in recent years, due to the increasing in the consumption of PET, that the interest in this machine is growing continuously in the domestic market and international markets as well.
Dega has also become specialized in electronic systems and has succeeded in optimizing the starting point of crystallization process, being aware that any lack of precision in this phase cannot be offset in the subsequent processing stages.
There is a special microprocessor control which helps to reach the first crystallization process starting point. Afterwards, the process continues automatically with heating proceeding at constant temperature, which varies according to each specific type of material.
The processed material falls onto a valve and, after passing through a screw feeder, stored in a big bag, or moved to a dehumidifier or directly to the extruder.
Substantial energy savings are possible by undertaking the Crystallization, De-humidification and extrusion processes in sequence. In fact, as the product is already at the temperature of 160°C, due to the Crystallization, it requires a small amount of energy to reach the dehumidifier temperature of 180°C, and subsequent plasticizing into the extruder, which means that the Crystallization process does not add any further costs to the process of recycling.
In order to meet specific request from the market, in addition to crystallization plants, Dega is able to guarantee its customer a fully comprehensive supply, including washing system built by other companies as well, thereby acting as a main contractor.
Our standard range includes machines with an output from 200 up to 1,000 kg/h but we also realized a unit that reaches up to 3,000 kg/h.
Our main customers are manufacturers of sheets and monofilament, but we have also many customers involved in injection or in blow-moulding as well.
DEGA – Your partner in plastic processing
