Bottles made of polyethylene terephthalate (PET, sometimes PETE) can "make lower-level products, such as carpets, to make food grade plastics, bottles need to be hydrolyzed into monomers, refined and then re-polymerized to create new PET Di many countries, PET plastic coded with resin identification code number "1" inside the universal recycling symbol, usually located at the bottom of the container.
Video PET bottle recycling
PET Usage
PET is used as raw material to make packaging materials such as bottles and containers to pack a variety of food products and other consumer goods. Examples include soft drinks, alcoholic beverages, detergents, cosmetics, pharmaceutical products, and vegetable oils. PET is one of the most commonly used consumer plastics. Polyethylene terephthalate can also be used as a key ingredient in waterproof paper making.
Maps PET bottle recycling
Process
Post-consumer waste
The empty PET packaging is discarded by the consumer, once it is used and becomes PET waste. In the recycling industry, this is referred to as "post-consumer PET." Many local governments and garbage collection agencies begin collecting PET post-consumer separately from other household wastes. In addition there are container storage laws in some countries which also apply to PET bottles.
It remains to be debated whether exports of circulating resources that damage the domestic recycling industry are acceptable or not. In Japan, foreign market pressures lead to significant cost reductions in the domestic market. Plastic costs other than PET bottles remain high.
Sorting
When the PET bottle is returned to the official redemption center, or to the original seller in some jurisdictions, a partial or full deposit is returned to the redeemer. In both cases, the collected post-consumer PET is taken to a recycling center known as a material restoration facility (MRF) where it is sequenced and separated from other materials such as metals, other rigid plastic objects such as PVC, HDPE, polypropylene, flexible plastics such as those used for bags (generally low density polyethylene), carton beverages, glasses, and anything else that is not made of PET.
Post-consumer PETs are often sorted into different color fractions: transparent PET, blue and green PET, and the rest being a mixed color fraction. The emergence of new colors (such as amber for plastic beer bottles) further complicates the sorting process for the recycling industry.
Processing for sale
Post-consumer waste sorted waste is destroyed, pressed into bales and offered for sale to recycling companies. PET post-consumer colorless/bright blue attracts higher sales prices than the darker blue and green fractions. The mixed color fraction is the least valuable.
Further treatment
Further treatment processes include crushing, washing, separating and drying. The recycling companies further treat PET post-consumer by shredding the material into small pieces. These fragments still contain residues of original content, torn paper labels and plastic caps. It is removed by a different process, producing pure PET fragments, or "PET flakes". PET flakes are used as raw materials for various products that should be made of polyester. Examples include polyester fibers (basic materials for clothing production, cushions, carpets, etc.), polyester sheets, binders, or back to PET bottles.
Filtration fused
Melt filtration is commonly used to remove contaminants from melt polymers during the extrusion process. There is a mechanical separation of contaminants in a machine called a 'screen changer'. Typical systems will consist of steel houses with filtration media contained in removable pistons or sliding plates that allow the processor to remove the screen from the extruder flow without stopping production. Contaminants are usually collected on a wire mesh screen supported on a stainless steel plate called a 'breaker plate' - a strong circular steel piece that is drilled with a large hole to allow the flow of the polymer to melt. For polyester recycling it is typical to integrate a screen modifier into an extrusion line. These can be pelletizing, sheet extrusion or strapping tape extrusion line.
Drying Polyester
PET polymers are highly sensitive to hydrolytic degradation, resulting in heavy molecular weight reduction, thus affecting further melting processes. Therefore, it is very important to dry the PET flakes or granules to a very low humidity level before melting the extrusion.
PET should be dried up to 100 per million (ppm) of water vapor and maintained at this moisture level to minimize hydrolysis during the melting process.
Dehumidifying Drying - This type of dryer distributes hot, de-humid dry air into the resin, sucks air back, dries it and then pumps again in closed-loop operation. This process reduces the moisture level in PET up to 50ppm or lower. The efficiency of moisture removal depends on the dew point of the air. If the dew point is not good, then some moisture remains in the chips and causes loss of IV during processing.
Infrared Drying polyester pellets and flakes - New types of dryers have been introduced in recent years, using Infrared drying (IRD). Due to the high rate of energy transfer by IR heating in combination with the particular wavelength used, the energy costs involved with this system can be greatly reduced, along with its size. The polyester can be dried and amorphous flakes crystallize and dried in just about 15 minutes to the surrounding moisture level. 300ppm in one step, and down to & lt; 50 ppm using a hopper buffer to complete drying in usually less than 1 hour
Global stats
Worldwide, approximately 7.5 million tons of PET were collected in 2011. This provided 5.9 million tons of flake. In 2009 3.4 million tons were used to produce fiber, 500,000 tons to produce bottles, 500,000 tons to produce APET sheets for thermoforming, 200,000 tons to produce strapping bands and 100,000 tons for other applications.
Petcore, the European trade association that cultivates PET collection and recycling, reports that in Europe alone, 1.6 million tonnes of PET bottles were collected in 2011 - more than 51% of all bottles. Once exported bales are taken into account, 1.12 million tons of PET flakes are produced. 440,000 tons were used to produce fiber, 283,000 tons to produce more bottles, 278,000 tons to produce APET sheets, 102,000 tons for solid tapes and 18,000 tons for other applications. (Source: PCI for Petcore and EuPR)
In 2008 the number of post-consumer PET bottles collected for recycling and sale in the United States was approximately. 1.45 billion pounds.
In 2012, 81% of PET bottles sold in Switzerland are recycled.
Increased energy prices can increase the volume of recycled PET bottles. In Europe, the EU Waste Framework Directive mandates that by 2020 there must be 50% recycling or reuse of plastic from household streams.
In the United States, the recycling rate for PET packaging is 31.2% by 2013, according to a report from The National Association for Pet Container Resources (NAPCOR) and The Association of Postconsumer Plastic Recyclers (APR). A total of 1.798 million pounds were collected and 475 million pounds of recycled PET was used out of a total of 5,764 million pounds of PET bottles.
PET bottle recycles globally
Reusing PET bottle
PET bottles are also recycled as they are (reused) for various purposes, including for use in school projects, and for use in solar water disinfection in developing countries, where empty PET bottles are filled with water and left in the sun allowing disinfection by ultraviolet radiation. PET is useful for this purpose because many other materials (including glass windows) that are transparent to light look blurry against ultraviolet radiation.
The new usage is as a building material in third world countries. According to online sources, the bottles, in the labor-intensive process, are filled with sand, then stacked and stacked or cemented to form walls. Some bottles can be filled not by air or water, to put light into the structure.
See also
- Health and environmental issues with plastic bottles.
- Plastic recycling
- Plastiki
References
External links
- (in French) EcoARK
Source of the article : Wikipedia
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