Industrial Utility Efficiency
Given that compressed air leak management programs are meant to save energy, reduce CO2 emissions, and generate ROI, DENSO’s Maryville, Tennessee, manufacturing facility can definitively say it has scored a trifecta when it comes to results – and reaped benefits beyond hard numbers alone.
A pharmaceutical plant, has had a compressed air assessment performed on two plant systems. The studies uncovered poor compressed air production efficiency, high air dryer loss, and problems with high flow compressed air uses negatively affecting plant pressure. The plant implemented energy efficiency measures, on the two compressed air systems, saving 46 and 64 percent in energy costs respectively.
In an ideal world, we would all have plenty of space, time and money to create the perfect compressed air system. In practice, we have to balance our ideals versus what we can actually accomplish. Compressed air systems take considerable forethought and planning to achieve a perfect install; however, we can use some key takeaways from this article even if we are ever faced a less than ideal installation. Remember to keep the compressors cool, minimize piping pressure drop and to allow sufficient room around the equipment for service.
One of the most common problems in plants is low air pressure. One of the most common solutions is to purchase new air compressors. Often this advice leads to a poor return on investment with the company’s hard-earned money. Often the issues are related to demand, distribution, or both. Solving the wrong problem can be expensive from a capital and operating cost perspective. Determining root cause analysis may cost more up front, but will save tens if not hundreds of thousands of dollars long term.
This article is going to identify two air compressor control situations that will preclude translating air use reduction in the production area into lower input energy into the air compressor.
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.
Compressed air contains contaminants such as dirt, water and oil which must be removed before use. ISO8573.1 specifies air quality classes for these contaminants. Humidity is expressed in terms of Pressure Dew Point (PDP). PDP is the temperature at which air is fully saturated with moisture, when the air temperature falls below this point further condensation will occur.
Many are familiar with the advances with improved technology in the compressed air supply. Such advancements as, proactive central air compressor controls to maintain optimum operation of multiple compressors to support ever changing air demands; improved drive systems such as VSD’s; magnetic bearing drives (centrifugals); and more efficient and reliable equipment taking advantage of modern manufacturing capability. These new technologies are very important in generating relative high energy cost savings, and are well promoted by the OEM equipment manufacturers.
Their job is to brake the cars by gripping the wheels. They are operated either pneumatically or hydraulically, with Alton & Southern Railway’s system using the former. Considering much of Alton & Southern Railway’s compressed air piping system dated back to its 1960’s installation date, there were leaks. As of 2012, it was determined one and a half compressors were running at 100% capacity just to maintain leaks. This equated to about 1,500 cfm at a cost of roughly \$180,000 in electricity annually.
A Canadian poultry plant has upgraded their aging compressed air system for their new expansion, making it significantly more energy efficient and also solving ongoing pressure problems. The project has given the facility a much better system overall and increased system capacity enough to cover additional compressed air load. This article describes what was done to improve their compressed air system.
A zinc producer spends an estimated \$516,000 annually on electricity to operate the air compressors in a compressed air system at its north American plant. The current average electric rate, at this plant, is 5 cents per kWh, and the compressed air system operates 8,760 hours per year. This system assessment recommended a group of projects able to reduce these energy costs by fifty-one percent (51%) to an annualized \$270,000. The simple payback of the project was 15 months – without taking into account potential incentive dollars from the local utility.
