Industrial Utility Efficiency    

System Assessment

One of the most satisfying parts of being a compressed air system auditor is resolving compressed air system reliability issues. This article exposes a seldom, if ever, mentioned problem that can occur when air dryers are dedicated to air compressors. It examines a real-world application and discusses the action taken to remedy the situation.

Compressor Controls

It was early summer, the air compressors were above the production floor on a mezzanine, and temperatures were heating up both outdoors and indoors. The compressed air system was comprised of three 500-horsepower centrifugal air compressors, and one 350-horsepower variable speed drive oil-free rotary screw air compressor.

Piping Storage

An air receiver tank (sometimes called an air compressor tank or compressed air storage tank) is a type of pressure vessel that receives air from the air compressor and holds it under pressure for future use. The tanks come in a range of sizes and in both vertical and horizontal configurations. An air receiver tank provides temporary storage for compressed air. It also helps your compressed air system run more efficiently.

End Uses

For Imerys S.A. there’s little question about the importance of managing dust collection systems it uses to control and reduce harmful particulates in its worldwide minerals processing facilities. And now there’s zero doubt about the tremendous energy savings it stands to save by reducing the amount of compressed air needed for these same dust collectors.

Pressure

Most industrial systems like compressed air have essentially random demand if you look at the long-term life cycle of the system. Hundreds, even thousands of independent small and large subsystems require constant or varying flow. These demands are typically not timed or synchronized with each other, so they aggregate to a fairly random flow profile, within a range. That range changes significantly when production processes change. Certainly a 2-week audit might show some patterns that appear predictable for demand A (“production”) and demand B (“non-production”) or day type, but they change over time as the plant adapts to new production systems and removes old ones. If demand was that profile forever, a lesser experienced auditor might be tempted to size one set of compressors that work perfectly for that profile but not for alternates.

Air Treatment/N2

Dew point is simply the temperature to which air must be cooled for the water vapor within to condense into dew or frost. At any temperature, there is a maximum amount of water vapor that the air can hold. This maximum amount is called the water vapor saturation pressure. If more water vapor is added beyond this point, it will result in condensation.

Leaks

Awareness and interest in leak detection only continues to grow thanks to a number of factors. What we have seen over the last 20 years is a more sustainable way of thinking, established international energy efficiency standards, reliable leak detection technology, and best practices to implement leak detection.

Pneumatics

In manufacturing and packaging facilities that rely on pneumatics, there’s a four-letter word worse than virtually any other: leak. Unidentified air leakage and unexpected maintenance in pneumatic systems are significant sources of revenue and productivity loss but identifying the cause of leakages and preventing unforeseen downtime is typically a challenge.

Vacuum Blowers

Every municipality and utility is facing the reality of rising energy costs. In 2010, the Town of Billerica, MA, which is located 22 miles northwest of Boston with a population of just under 40,000 residents, engaged Process Energy Services and Woodard & Curran to conduct an energy evaluation of the Town’s Wastewater Treatment Facility (WWTF) and pump station systems sponsored by National Grid. The objective of the evaluation was to provide an overview of each facility system to determine how electrical energy and natural gas were being used at the facility and to identify and develop potential costsaving projects.
In this series we covered some very common issues in the Compressed Air Generation or “Supply Side” with regard to misapplying some capacity controls and installing different types of air compressors with piping and/ or orientation. These can preclude any reduction in compressed air demand on the production side from effectively translating lower air usage into a commensurate level input energy.
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.
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 large mining complex in a remote northern region of the world invited a compressed air auditor in to assess the efficiency of a problematic system. Site personnel and their air compressor supplier were concerned a system in one of the buildings was not running optimally, and wanted to know what size of compressor to install in the facility. The auditor found significant savings in this target system, but even larger potential savings were found in other ancillary systems in the complex, as part of an extra investigation conducted while at the site. Overall, the potential energy savings total more than half of a million dollars, if all recommendations are implemented.