PETpla.net Insider 11 / 2010

MATERIAL / RECYCLING 22 PET planet insider Vol. 11 No. 11/10 www.petpla.net Melt-To-Resin (MTR) technology - Elimination of the solid-state post-condensation (SSP) process Cost-efficiency in PET resin production (USA) in September 2009, with the second line coming on-line in June 2010. MTR technology eliminates the need for solid-stating: High-molecular PET material with almost the required intrinsic viscosity is obtained directly during melt polycondensation by means of a special high-viscosity fin- ishing reactor - the so-called Discage MV Reactor. The chief advantage of the MTR technology is that the cost-intensive SSP stage is no longer required. Major savings relate to a reduction in electrical and heating energy due to the following: there is no heating of the PET precur-  sor chips as solid-stating is eliminated the nitrogen circuit with its booster  blowers and nitrogen purification unit is also eliminated for the same reason the 2-reactor melt-phase process  replaces multi-stage reactor cascades the so-called Espree reactor does  not require agitators process steam is used to generate  a vacuum by means of steam jets. It is said that this proprietary tech- nology from Uhde Inventa-Fischer improves the energy efficiency of PET production by about 40% compared to the conventional route with an SSP stage. In addition, preform manufac- turers and bottle producers appreci- ate the high quality of MTR resin, and many well-known brand owners have approved MTR resin for their bottle production. Recent experience also indicates that converters may ben- efit from the fact that less energy is required for melting MTR resin due to its significantly lower degree of crys- tallinity compared to SSP material. Flake-To-Resin (FTR) tech- nology - Uniform virgin-like bottle resin from recycled PET flakes Flake-To-Resin (FTR) technology is Uhde Inventa-Fischer’s proprietary recycling technology for food-grade PET packaging. FTR has been cleared by the US Food and Drug Administra- tion (FDA) for food contact applica- PET production plant using MTR technology PET is produced by polymerising the feedstocks purified terephthalic acid (PTA), isophthalic acid (PIA) and ethylene glycol (EG) using a melt polycondensation process. Conven- tional routes have commonly required a subsequent solid-state post-conden- sation (SSP) step to further increase the molecular weight of the polymer. During this so-called solid-stating, PET precursor chips are typically sub- jected to a temperature above 210°C, and a counterflow of purified nitrogen is used to avoid polymer degradation. However, the SSP stage is energy- consuming and as it is an extra step, it also has the disadvantage of requiring additional plant equipment and oper- ating personnel. MTR - technology In 2007 Uhde Inventa-Fischer’s MTR technology was introduced to the PET industry. Three world-scale MTR plants with a total production capacity of more than 800,000t/a have already come on-stream. The world’s biggest MTR plant was com- missioned for Indorama in Alabama Energy costs have become a crucial cost factor for produc- ers of PET. Annual energy costs can amount to up to 8 mil- lion euros for an output of 200,000t/a and in general, energy prices are expected to increase even further. Low energy consumption during the production of PET bottle resins therefore creates a competitive advantage for PET produc- ers. New technologies from Uhde Inventa-Fischer, such as the Melt-To-Resin (MTR) technology and the Flake-To-Resin (FTR) technology, help PET producers to improve energy efficiency.