Watching South Park In Windows Media Player

Petretec Process (Technology Polyester Regeneration)

Dupont has a long history in the recycling of plastics. Primeors were mechanically reprocessed PET in beginning in 1988. Dupont's story is the story of the production, use and recycling of polyesters. Focused on the problem of recycling of PET, Dupont developed four objectives, according to Mike Harnagel, vice president and general manager of DuPont Films. These objectives were:

• Avoid dumping of polyester waste materials.
• increase knowledge of the green aspect of Polestar materials to the public.
• Reduce consumption general petroleum.
• Keep the chemical value of the polyester.

To achieve these objectives Dupont desrrolló a completely new recycling technology. This process is known as green Polyester Regeneration Technology (Petretec). The company invested $ 12 million to transform an existing facility to operate with the new recovery technology. The process can treat Petretec polyester films, fibers and plastics with much higher levels of pollutants that mechanical recycling accepted as recyclable material. The process uses chemical reactions Petretec essentially based on "decondensed" polyester molecules.

Petretec The process begins with the determination of levels of contaminants in the waste PET. Any PET containing metals, dyes or other materials that would interfere in the recycling are separated and used for the mechanical recycling, landfill or incineration. The remaining PET is dissolved in DMT at temperatures above 220 C, forming a solution of DMT PET waste. In a transesterification reaction depolymerizing the PET reacts with methanol to produce the original monomers of the polymer as shown below. The reaction is carried out on an industrial scale methanolysis reactor at 260-300 C and a pressure of 340-650 kPa.

methanolysis reactor, the DMT and ethylene glycol (EG), mixed with an excess of methanol was passed through a column of elimination of methanol. Methanol removed in this way is recycled in the process. The DMT and EG form an azeotrope that prevents their separation by distillation. To achieve this, the Dupont chemical added methyl p-toluate (MPT) at this point Petretec process. This forms an azeotrope MPT and EG, which allows the separation of the two other DMT components. The distillate MPT / EG forms a two-layer solution. The top is enriched with MPT and can be recycled in the process. The DMT is a fractional distillation to increase its purity.