Krones, acting as general contractor in the project for the new Polymer Center in Las Vegas, worked hand in hand with Stadler, which was responsible for mechanical sorting on the PET and PO lines. The new plant will produce more than 100 million pounds per year of recovered resin products that are returned to the circular economy.
The new Polymer Center processes presorted plastics collected by Republic Services across the Western United States to recover PET, which is converted into recycled PET (rPET) flakes ready to be turned into new bottles, and Polyolefins (PO) ready for use in the production of new bottles, jugs and containers.
This was an important project for Republic Services that required careful planning and research to select the best partners: “We started to think about the Polymer Center business model in 2019,” explains Pete Keller, Vice President, Recycling and Sustainability at Republic Services. “We chose Stadler and Krones because we think we’re going to produce the highest-quality and highest-value product in the marketplace. We had familiarity with Stadler’s equipment and people, and we knew we were going to get a solid design. We consistently heard that the Krones wash line produced the highest-quality rPET flake in the marketplace. These systems give us the ability to produce both food-grade and color-sorted materials in a way that hasn’t been available to the market in the past, enabling greater material circularity.”
The Polymer Center in Las Vegas sorts and processes the materials, which are delivered in bales, on two lines: one for PET and one for mixed plastics, each with a capacity of 5t/h. “This is the largest Dual Line plastics recycling plant in the USA,” comments Mat Everhart CEO, Stadler America LLC (a subsidiary of Stadler Anlagenbau GmbH). It is expected to put 100 million pounds of plastics a year back into the circular economy by producing high-quality, food-grade recycled material ready for use in packaging.
The materials fed into the PET line undergo mechanical separation and the singulated material is cleaned of ferrous particles. A Stadler STT2000 ballistic separator sorts the material into rolling (3D), flat (2D) and fines fractions.
The fractions go through sensor-based sorting with Near-Infrared (NIR) sorters. Caps, rings, and the 2D fraction go to compactors. The 3D fractions are directed to a Stadler Label Remover to remove the labels. The clear PET, caps and rings are directed to the Krones washing line, which granulates and cleans the material, while the color PET is compacted into bales.
On the Mixed Plastics treatment line, mechanical separation sorts the infeed into fines and sieve overflow – the latter further separated into light and heavy fractions. The heavy mixed plastics fraction is sorted into four Polyethylene (PE) products – Natural, White, Red/Orange/Yellow, Other/Color – and two Polypropylene (PP) products – Natural/White and Other/Color.
PET is sorted out of the remaining material and sent to the PET line. The products of the Mixed Plastics line are conveyed to storage bunkers where a semi-automatic feeding program allows for materials to be discharged by grade to be fed into the baler.
The company plans to build three more Polymer Centers to address the gap between supply and the fast-rising demand for recycled plastics driven by regulations and a shift in consumer preferences for sustainable packaging. A report by the Recycling Partnership estimates that the gap between the current US supply of rPET for use in bottles and the projected demand in 2025 is close to 500,000 tons.
Following the positive experience working with Stadler on the Las Vegas Polymer Center project, Republic Services has decided to extend this collaboration: “Our strong partnership with Stadler and Krones, the design and quality of equipment, and successful implementation in Las Vegas has given us the confidence to purchase systems 2 and 3 for our centers under development,” concludes Pete Keller.