PET bottle production encompasses a series of processes starting from the delivery of raw resin to the production plant through storage, conveying, distribution, blending, drying, injection moulding and cooling. A further process may be preform storage or bottle stretch-blow. The evolution of preform production methodologies and technologies has pushed processing performance to the limit, to the point that these processes have reached maximum physical efficiency. Process control has evolved at the same high pace, allowing the high output and quality that are achievable today.
The latest developmental trends that increasingly characterise the industry aim to further enhance constancy of productivity, efficiency of operation and product quality. Piovan launched a new technology-development programme in late 2012, which was concluded in the first half of 2015. The resulting new innovations in PET processing technology focus on the auto-adaptability feature for the processes of drying and cooling, which Piovan first introduced to the industry in 2009. Piovan holds a patent for a high-efficiency system for dehumidifying and/or drying plastic materials, obtained in 2013, in recognition of its extensive research and results in process consistency and optimisation.
Images: Piovan.
The next generation in PET-drying technology
Drying of PET is an increasingly integral part of the process of transformation, to the point of becoming a necessary and crucial step. New applications and new types of PET, environmentally sustainable PET, modified PET for extrusion
blow-moulding processes and increased PET supply capacities require accurate and dependable drying performance.
PET is a highly hygroscopic resin, very susceptible to environmental conditions and storage means. If not properly dried and adequately thermally conditioned, it will experience a rapid drop-off in IV or an increase in acetaldehyde, which can be detrimental to the blow-moulding process or limit the use of PET containers respectively.
A typical resin drying process also consumes a large quantity of energy, requiring the resin to be exposed to hot, dry air for as long as seven hours. Given the high cost of energy today, a tremendous effort is focused on improving this process to be more energy efficient.
 |
Introducing Genesys
Piovan introduces Genesys, an innovative new resin-drying system designed to deliver the highest output and the highest level of constancy of physical characteristics of performs, at the lowest energy utilisation. Through the implementation of state-of-the-art technology such as loss in weight control, airflow management and stabilisation, flat, stable dew-point control, an intelligent full-heat-recovery regeneration process, and advanced industrial PC-based control, Genesys is the next generation of PET resin drying, and the only AUTO-ADAPTIVE system available today.
Airflow management and stabilisation are key to controlling energy transfer to the polymer. Piovan has developed and integrated into Genesys a proprietary automatic airflow control and adjustment to optimise energy utilisation and reduce consumption to 55% below today’s conventional resin-drying systems. Another exclusive and innovative feature of Genesys is the capability to stabilise the airflow in the drying hopper, to achieve stable thermal conditioning for a further drastic optimisation of energy utilisation.
Quantifiable energy savings
Because regeneration of the desiccant material requires tremendous amounts of energy, Genesys recovers almost the entire energy utilised in this step of the drying process. By doing this, Genesys is able to provide savings of 80% compared with traditional or current regeneration technologies. Genesys features the lowest energy use compared with other drying technology available today. For a system producing PET preforms running resin at a rate of 1,000kg/h, Genesys would produce savings of over 220,000kWh a year.
With the objective of providing customers additional guarantee of the energy savings that can be achieved with Genesys drying systems, Piovan appointed independent certification body TÜV to test a system installed at the premises of a European beverage manufacturer. Energy utilisation was measured at 69.2Wh/kg, (TÜV test report number 204325) after seven months of operation. This is the lowest value measured to date, showing how energy costs can be reduced by 50% with respect to traditional PET-drying systems.
TÜV specialists performed the test on a Genesys GP55 dryer, coupled with a 4,500L hopper and operating with a process air temperature of 175°C. The type of material processed is a PET resin with high intrinsic viscosity (IV 0.8dl/g), which is commonly used for the production of beverage bottles.
Piovan has focused its resources increasingly on developing a range of products that offer significant improvements on production output and constancy, along with a financially quantifiable level of energy savings. This TÜV result constitutes concrete and transparent proof of the flair for innovation in a company that has an excellent understanding of PET processing.
