It's high consumption of PET plastic beverage bottles in China at present. Recycling for wasted PET drinking bottles not only reduce pollution, but turn waste into wealth. However, only a small part being used, which lead to resource waste and environmental pollution. So its recycling technology has broad prospects.

There're two kind of method of recycling PET plastic beverage bottles, one is chemical recycling, another is physical recycling. Chemical recycling is one method that PET bottle is depolymerized     to form useful chemicals under certain reaction condition, such as low-grade petrol. Physical recycling is that PET bottle get through separation, crushing, washing and drying, then become into granulation. There're two kinds of Physical recycling, one is cutting PET bottle into flakes and separating  HDPE, aluminium, paper and binding agent from PET. Then, PET flakes get through washing, drying, granulation. The other is to separate bottle cap, bottom, label and ect from bottle firstly, then go through washing, crush, granulation.

The first technological process: Using artificial methods to remove the stones, wood and other plastic products as well as the colored PET bottles. Recycled PET cannot contain PVC impurities, because it is the key factor affecting PET colors. When little PVC is mixed, it can be separated artificially on conveyor belt. That is, different physical phenomenon appears at the forced part of  PVC and PET bottle, opaque mark will appear at PVC bottles, but PET won’t, then they can be separated. Also, some companies use the different melting point of PVC and PET, when the PET and PVC flakes go through the conveyor belt with controlled heater, PVC is melted and stick on the belt, then is separated with PET.

Separate the iron with ferromagnetic separator.

Some PET bottles only are crushed for one time, and some need to be subdivided for re-crushing after first crushing , finally become small flakes in 1.0-1.5cm. Sifter with 1.0-1.5cm hole is installed at the exit of crusher for controlling the size of flakes.

The technique of abstersion and separating impurities is the key to get the high-quality recycling PET. Normally plastic PE or paper label is used on drink bottles. Paper label can be sticked by   adhesives, or sticked during the blow moulding process. After PET bottles crushed, partial label is crushed into flakes, but some of them are still conglutinating on the PET flakes. After going through the separation facility composed by air-blower and turboseparator, 98% loosen label flakes can be removed. The exhausting tower separator is also available, the crushed flakes are added vertically fr the top of tower separator. The flakes and the updraft can form adverse current, because of the discrepancy of specific gravity between PET and label flakes, the label is taken out and PET come out fr the bottom of separator. During production, at least two separators are used for better efficiency of label separation.

The purpose of abstersion is to get rid of adhesives, dust, residue fr the bottles. The hot water in 80-100℃ is used for abstersion to soften or dissolve sticking label and EVA adhensive at bottom or other  kind adhensives. To avoid PET flakes being sticked by the fallen adhensive, some additive is added in the water, such as alkali, emulsifier or other special Chemical agents. The formula and content of clean agent is determined by fty based on the origin of waste bottle and the character of adhensive, the clean agent can be recycled through heating after filtering impurity. Abstersion can go along in the special jar with stirrer, normally the 2^nd – grade techonology of abstersion is used for better washed effect.

The separation of pedestal is based on the character of different density between HDPE and PET. It is within can washer, HDPE flakes overbrim fr the top of tank, and the falling PET flakes come out fr the bottom. Sometimes, water cyclone is used insead of flotation tank for better separating effect.

Usually dewatering centrifuge are used to lower the Water Content of PET flakers to 2%, then after go through belt-type or tubular dryer, the water content will be lowered to 0.5%.

PET can’t contain the aluminium impurity, even little aluminium impurity will affect the transparence of recycling PET, so the content of it must be lower than 50×10-6. The easiest way to separate aluminium is to remove aluminum cap, aluminum ring or use electrostatic separation to lower the aluminium content to 100×10-6, this can be produced on the conveyor belt. If  PET flakes go through the metal-inspection separator system, the aluminium content can be lower than 5×10-6.

Renewable PET extrusion granulation and original PET extrusion granulation have no great difference in addition to feeding. Extrusion granulation can use single-screw extruder or twin-screw extruder. But we must consider in design that the feeding pressure of traditional extruder is too high, so a screw of larger size can be used on the feeding part. If you have a higher require about the products, we propose to adopt the twin-screw extruder.

The latter process：This recycling method is separating non-PET component from PET bottle first, and then crushing and recycling. Firstly, it used artificial method to separate stones,wood,other plastic products and colored bottles. The separation of PVC bottle can use artificial selection methods or PVC separation equipment. Separation of metallic iron can use a magnet separator. Beverage bottles enter into the cleaning machine through conveyor, then bottles enter the processing production line vertically. Through tach remover and cover remover, we can remove the cover and tach, then through the weighing to ensure that the cap has been dismantled. If one bottle is detected more than the standard weight, it will be separated from the production line.

And then to inject 100ml boiling water into each waste PET bottle, dissolving the residual beverage of bottle. At the same time, the bottles are clamped and hanged. External part of bottle is rinsed by high-pressure water, and making the adhesive to soften with hot water. All of these steps can make the base get rid of bottle and remove the plastic or paper label. After washing,bottom of bottle will be resected and water of bottle will flow out. The device which fragmentation process needed is the same as the device of the first method. The continuous dryer dry the PET bottle flake to the water content less than 0.05%. Extrusion granulation method and the first recycling method is of the same.