Industrial Utility Efficiency    

Plastics

When compressed air is essential to the production of up to one million plastic containers per day there’s little room for error. That’s why Schoeneck Containers, Inc. (SCI) leaves no stone unturned to ensure its compressed air systems run smoothly at all times and without fail at its bustling facilities in Wisconsin.
In February 2021, Compressed Air Best Practices® Magazine interviewed members of the Intertape Polymer Group Inc. (IPG) Sustainability Pillars team to gain an understanding of the work being done to improve energy efficiency. The team members interviewed were Michael Jones (Director of Corporate Energy), Michael Deitering (Senior Project Engineer), Jarrod Knapp (Maintenance Manager) and Mark Secord (Engineering Group Leader).  
By making changes primarily focused on compressed air uses, Winpak, an international plastics products manufacturer based in Winnipeg, Manitoba, Canada, increased compressed air production capacity and reduced annual energy consumption by 33%. These benefits have been accomplished while the company was making the switch to lubricant-free compressed air to support product quality goals. This article discusses some of these changes and addresses measures that could be implemented in any compressed air system.
For more than 20 years, Hungarian-based Doroti Pack Ltd. has specialized in the production and servicing of state-of-the-art packaging machines. Their focus is on developing, manufacturing, producing and selling premium-quality packaging equipment, including their line of DorPack thermoforming machines which are often used for food products such as fresh meat, fish, dairy products, bakery ware, confectionery and ready-cooked foods. Dorati Pack chose to incorporate Aventics pneumatic components in latest thermoforming machine for optimal productivity and machine longevity.
On a recent project, at a polyethylene terephthalate (PET) blow-mold and filling operation, a very effective measurement plan resulted in a full synchronization of the supply side air to blow molds with significant reduction in total air use and increases in productivity and quality.  
The plant produces both molded and blow molded plastic parts on a 5 day per week, three shift schedule. Production and maintenance sometimes occurs on weekends, occasionally requiring the air compressors to run on a 24 x 7 basis so the practice was to leave the compressed air system always pressurized. The system consisted of three modulating lubricated screw compressors one sized at 150 hp and the others 125 hp (3 units), each controlled with their local compressor controllers.
The Pepsi bottling plant in Winnipeg, Manitoba has upgraded both their main 100 psi compressed air system and their 600 psi PET bottling system in two separate projects. The system improvements have saved the company both maintenance and electrical operating costs, and even reduced some winter heating demand.
A plastic product manufacturer spends an estimated $245,000 annually on electricity to operate the air compressors in a compressed air system at its plant located in a midwestern U.S. state.  The main manufacturing process is plastic extruding. The current average electric rate, at this plant, is 7 cents per kWh. The compressed air system operates 8,760 hours per year and the load profile of this system is relatively stable during all shifts.
At a Midwest window manufacturing plant, the cooling process for the plastic frame pieces, after leaving the extruder, was critical to process productivity and quality. Too much cooling air (or not enough cooling air) would generate scrap and rejected product. The plants’ 17 extruders and 55 separate blow-offs in these lines had similar cooling stations at the cooling boxes. They consisted of about three hoses at each exit frame angled down to the extruded piece moving past it. The compressed air flow was controlled by a manual control valve set by an operator. The operator used his experience to control the flow delivered and thereby control the product quality.
Technological trends in plastics manufacturing are driving the costs of production down. In industrial PET blow molding specifically, two innovative techniques have had major impacts over the last 15 years: “light weighting” the plastic bottles, and recirculating high-pressure compressed air. Both have helped to improve the energy efficiency of PET blow molding by reducing compressed air requirements dramatically.
PET Power Containers, a Canadian manufacturer of PET plastic containers, had plans for expanding its operations with the addition of more blow-molding equipment. Before the expansion could happen, however, the company needed to assess its compressed air system. Based in Vaughan, Ontario, PET Power provides a dizzying array of differently shaped and sized plastic bottles. Their operations run 24/7, and compressed air plays a key role in their primary manufacturing applications, including PET blow molding, PET preforming, and labeling bottles.