Paying close attention to compressed air use is paramount for identifying potential energy-saving projects. The engineering team at Ball Corporation has been well aware of this fact for years. An active member in the Environmental Protection Agency’s ENERGY STAR® program, Ball Corporation scrutinizes manufacturing processes to maximize the energy efficiency of compressed air systems in each of its plants.
Ball Corporation is an active participant in the Environmental Protection Agency’s ENERGY STAR program.
Ball’s facility in Saratoga Springs, New York, services beverage companies throughout the northeastern United States. The plant manufactures multiple aluminum can sizes on four production lines, producing millions of aluminum cans per day.
Compressed air accounts for a significant percentage of the total power consumption at the Saratoga Springs facility. They operate both low-pressure and high-pressure compressed air systems.
To learn more about Ball Corporation’s Saratoga Springs facility and how their plant engineers optimize for compressed air efficiency, the team at Compressed Air Best Practices® Magazine spoke with Bob Nelson, the facility’s Engineering Manager. During our conversation, Nelson told us about demand-side projects they have implemented to reduce compressed air demand. He also described modifications performed on the supply side to better accommodate the lower demand.
Compressed Air System Setup at the Saratoga Springs Facility
It takes a long-winding chain of manufacturing processes to turn raw aluminum coils into small aluminum cans. Consequently, there is a large range of applications at the Saratoga Springs facility, each requiring different compressed air pressure. To prevent regulating high-pressure compressed air down for low-pressure applications — like conveying cans — the Saratoga Springs facility has two compressed air systems in place. The high-pressure system runs at about 90 psi, servicing equipment in need of compressed air at greater than 80 psi. The low-pressure system provides compressed air at 50 psi — some of which is regulated down.
Partnering with a knowledgeable compressed air system supplier has been beneficial for Ball Corporation. The company’s national partner, Blackhawk Equipment, has provided both compressed air and process expertise.
“Blackhawk Equipment has been in many Ball plants around the world providing equipment and expertise, and they are very familiar with the applications,” Nelson said. “Chris Gordon at Blackhawk is a great resource. He’s done a ton for us.”
Production Team Guides Equipment Vendors to Use Less Compressed Air
The production equipment at Ball Corporation has a “superintendent team” with knowledge specific to each process. According to Nelson, they really understand the equipment and all of the manufacturing processes throughout the plant. However, when it comes to support equipment (i.e. air compressors, vacuum pumps, etc.), there were times when they did not realize how a change would impact the system. Nelson has been at the plant in Saratoga Springs for 16 years, and has been a major driver in educating the production team about their resources.
“I try to teach everyone a little bit about the support equipment and compressed air demand,” Nelson explained. “When I first came on board, they were having some problems in production. And so they would just say ‘we need more compressed air’ — and then somebody would start up another air compressor. I’d go back there and find all three compressors blowing off.”
Once the production team understood pressure and flow, they starting taking ownership of how much compressed air the machines used. To reduce demand, the team talked to OEMs, and some vendors were able to make design adjustments to push the pressure requirements down.
“They [the production team] talked to the OEMs and came up with the latest designs,” Nelson told us. “We were able to upgrade all the equipment to this new design that uses less compressed air. We were able to turn our pressures down, and the leaking issues also went away. It’s all part of their culture now, to take a look at compressed air use.”
Monitoring Compressed Air for Preventative Maintenance
Paying attention to compressed air use has yielded another benefit for the production team. On certain pieces of equipment, compressed air is measured and charted. It is also displayed on several tools available at Ball, providing easy access to information, such as pressure and volume trends. With that information easily accessible, production can use it as a preventative maintenance tool.
Over Nelson’s tenure at the plant, the overall demand-reduction effort has resulted in substantive drops in compressed air use.
“When I first got here, we were running about 11,000 cfm total, and a big portion of that was on the high-pressure side,” Nelson said. “Over time, we’ve reduced the number significantly.”
“Right Sizing” the High-Pressure Compressed Air System
Demand-reduction projects fed into supply-side opportunities, where Ball could reevaluate required capacities and drive big savings in energy. The effort started on the high-pressure system, where consistent throttling occurred due to oversized capacity.
“A big part of our reduction was getting the right air compressors in place,” Nelson told us. “We had three 900-hp air compressors. And if we had three of them running, one of them was blowing off. We’ve gone through a series of projects to ‘right size’ the high-pressure air compressors, and that is where all these projects started.”
Originally, the high-pressure compressed air system had three centrifugal air compressors in place. As demand decreased, Nelson said they “went from running three machines, to two machines, to one,” getting to the point where one would still blow off air. Ball worked with its vendor to redesign the air end and put a 600-hp motor on the machine, reducing its capacity to efficiently provide 2200 scfm at 100 psi. While this worked for several years, demand was eventually reduced too far below the machine’s optimal performance curve, and it used 23.3 kWh per 100 cfm.
“After a while, we got down to around the 1550 cfm, and we were blowing off 99 percent of the time,” Nelson said. “The valve would be open 20 or 30 percent, so we started putting together a program to replace the compressor. We went to a flooded screw 400-hp machine with a variable speed drive — two stage. And that machine uses 262 kilowatt-hours for the same output, so that’s 16.9 kWh per 100 cfm.”
Ball also worked to change some of the process equipment over to the low-pressure compressed air system, since a lot of the high-pressure air was being regulated down to 45 or 60 psi. While it required plumbing work, the project saved energy by eliminating over-pressurized air. According to Nelson, the team at Ball found as much process air as possible on the high-pressure system and transferred it to the low-pressure system, enabling them to right size the high-pressure compressors and prevent blow off.
Retrofitting the Low-Pressure Compressed Air System
On the low-pressure side, the original air compressor was a rotary screw machine. According to Nelson, it “was more of a constant volume, variable pressure type of compressor.” Consequently, a blow-off system was put in place to maintain a consistent pressure, because the varying pressure impacted the quality of the necking process.
“In order to hold a constant 40 psi, the discharge of that compressor was connected to a blow-off valve set at 40 psi,” Nelson said. “It basically made a false load on the compressor, keeping it running at a constant discharge pressure after that blow off.”
To retrofit the system, Ball replaced the older low-pressure machine with a two-stage, 1250 hp centrifugal compressor. The newer compressor enabled Nelson to modulate the intake instead of blowing off excess pressurized air.
“We went with a two stage 1250 horsepower centrifugal air compressor,” Nelson said. “That enabled us to modulate the intake and not blow off. That saved us probably, all in all, at least 1000 or more cfm. Our average flow is 4850 cfm at 50 psi. Right now, we’re averaging 15.2 kWh per 100 cfm of air.”
Energy rebates have made all of these projects more compelling. Nelson said all of the “projects have been funded between 33 and 50 percent by rebates.” Ball goes through pre-measurement and post-measurement stages to prove energy savings and receive payback. According to Nelson, that has “really helped getting capital funds approved through the corporate system.” Doug Barndt, the Manager of Demand Side Energy – Sustainability at Ball Packaging Americas, has also been a major proponent of compressed air system improvements throughout the organization.
Driving Energy Costs Down
Ball Corporation’s dedication to energy management has yielded tangible results. Being an active member in the Environmental Protection Agency’s ENERGY STAR® program has helped. To date, the Saratoga Springs facility has seen a significant reduction in electrical energy (kW) use — resulting from compressed air system refinement and other process changes. As Nelson said, “We’re always looking to improve efficiency here in New York.”
To read more about Sustainability at Ball Corporation, visit www.ball.com/sustainability.
To read more about Industrial Energy Management, visit www.airbestpractices.com/energy-manager.