Industrial Utility Efficiency    

Plastics

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.
As in most industrial categories, compressed air is critical to the operations of a plastics plant whether it is blow molding, injection molding, or other processes. The opportunities to improve supply side (compressor room) efficiency are similar to all industrial compressed air systems, but are even more prevalent in some plastics facilities, especially blow molding.
Most P.E.T. bottle-blowing machines require anywhere from 550 psig (38 barg) to 580 psig (40 barg) and an air flow of 247 cfm FAD (420 m3/hr) to 3700 cfm FAD (6290 m3/hr). The air compressor technology used most prevalently for this application is the double-acting, oil-free, water-cooled, reciprocating air compressor. With the higher pressures and air flows that are required, the P.E.T. bottle blowing market is a strong niche market for the double-acting oil-free reciprocating (piston) compressors.  
The NPE2009 international plastics showcase was held June 22-26 in Chicago’s McCormick Place. While attendance was down from NPE2006, the preliminary total of visitor registrations numbered 44,000. Sustainability and energy efficiency was a prominent topic in the booths of exhibitors. Manufacturers of compressed air and injection molding equipment had many developments with Sustainability to show the visitors to NPE2009.
Resin drying is a critical step in the manufacturing process of injection molding, extrusion molding and stretch blow molding.  Compressed air resin dryers are one of the most commonly used dryers in the plastics molding industry. Recent advancements in compressed air membrane-type resin dryers, have reduced the associated energy costs significantly.
Over the last several decades, Air Power USA has reviewed many various types of plastic injection molding operations throughout the U.S.
Compressed Air Best Practices interviewed Paul Lukitsch.  Mr. Lukitsch is the Regional Facilities & Energy Manager for Millipore Corporation.
The facility is a plastics injection blowmolder and is a division of a large corporation. The following information was produced from a compressed air system assessment done over seven days.