UnPET process

The UnPET process for the depolymerisation of PETP has been developed by United Resouree Reeovery Corp. The proeess is elaimed to effieiently remove impurities present in post eonsumer PETP serap, even those present at a concentration of 40% or more. Key stages of the process whieh is proteeted by patent, are deseribed, and also details of the eompany s plans to invest over 5 million US dollars in a new faeility based on UnPET teehnology. UNITED RESOURCE RECOVERY CORP. 

The UnPET-process of the United Resource Recovery Cooperation [21] uses a concentrated alkaline solution for the saponification of finely grounded PET. In this process a preceding cleaning treatment is not necessary. The alkaline/PET mixture is heated to 230-290°C in a rotary kiln. After vaporizing the water the PET is saponified. Also EG is vaporized and collected. Impurities such as paper and polyethylene are oxidized by air. 

Base-catalyzed hydrolysis always leads to the TPA salt of the cation used. Releasing the salt by neutralization leads to large amounts of waste salts such as NaCl or Na2S04 or a complicated treatment of the sodium terephthalate. Figure 25.7 shows the neutralization scheme for sodium terephthalate with CO2 for the UnPET process. All components run in cycles. Just TPA, EG, CO2 and water are released. This product treatment needs five... 

Figure 25.7 UnPET process and neutralization of Na2Tp (sodium terephthalate) with CO2 avoiding the production of salts...

UnPET [United Resource Recovery PolyEthylene Terephthalate] A process for recycling waste PET (polyethylene terephthalate). The PET is first hydrolyzed by hot aqueous alkali, and the product then undergoes five complex processes. The only products leaving the process are terephthalic acid, ethylene glycol, carbon dioxide, and water. Developed from 1996 by the United Resource Recovery Corporation, Spartanburg, SC, and operated on a large scale in Switzerland, Germany, and the United States. 

United Resource Recovery Corporation This outfit were the originators of the UnPET and ElybridUnPET processes. The former appears to be a saponification process. The latter is less clear, but appears to at least include an additional grinding stage to increase the efficiency of the overall process. The company is currently mainly involved in licensing out these processes to other recyclers. The website is www.urrc.net. 

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