August 14, 2020
Sustainability drives compressed air upgrades at major seafood facility
As Gorton’s moved forward with its plan to upgrade their compressed air system, the first step was to replace the existing compressors supplying air to pneumatic systems around the plant. “Gorton’s had three reciprocating compressors that were close to 40 years old,” according to Whelan. “Two were 150 hp units and the third was 100 hp. There were no integrated dryers, so each compressor had its own independent dryer as well. That quagmire of equipment was replaced by three Atlas Copco Z/MD systems, each housed in a compact, fully-integrated cabinet. The lead machine has energy efficient, variable speed drive control and will trim the load at all times, maximizing efficiency. A new Atlas Copco ES series sequencer controls the operation of all three machines. This equipment is vastly more energy efficient, much quieter in operation and far more reliable. It takes up less space and looks much better, too”
The next part of the project involved Gorton’s five ADF freezers. “Dry air is crucial in our freezers,” says Gazda. “A rise in dew point could freeze the coils and negatively impact product quality.” Each of Gorton’s ADF freezers had a separate, stand alone, heatless desiccant dryer to lower the compressed air dew point to -40F. This type of dryer requires frequent regeneration using compressed air purge to remove moisture adsorbed from the output airstream. While this setup is effective, it is not very efficient as a great deal of electricity is consumed to produce the large volumes of compressed air used for the purge. “With the new Atlas Copco compressors and MD dryers, we are running well below the -40°F dew point we are used to,” according to Gazda. “Still, there could be times, if it got really muggy, that we couldn’t be 100% assured of achieving the low dew point we must have.” Whelan designed a solution to ensure the low dew point air that Gorton’s requires for the freezer – even during periods of high ambient humidity – with minimal power consumption. “With an Atlas Copco MD dryer, air coming out of the compressor is already very dry,” Whelan explains. “To be absolutely certain that the dew point would always meet the specified level, I recommended an Atlas Copco AD300 heated trim dryer to polish the air before the freezers.” The AD application is perfect after an MD dryer since the unit can stay on line for weeks at a time before requiring full regeneration and the accompanying purge loss. “Probably 95% of the time we don’t need the additional drying,” according to Gazda. “But our freezers absolutely need -40°F air, so provisions are now in place with the polishing dryer.” Gorton’s went from five heatless desiccant dryers that consumed large volumes of compressed air for frequent regeneration, to one zero-purge MD dryer supported by one AD polishing dryer. The MD/AD combination reduces Gorton’s annual electrical consumption by 44,000 kWh or $8,000 per year. This project was also submitted to National Grid and qualified for an energy incentive.
Gorton’s further enhanced its sustainability efforts by incorporating Atlas Copco’s Energy Recovery Option into their new Z compressors. Compressing any gas, including air, produces heat. This heat is typically wasted to the atmosphere through a cooling fan for air cooled compressors or a cooling tower for water cooled compressors. Atlas Copco engineers devised an innovative system that captures the wasted heat of compression so it can be reused in the form of discharge hot water off the compressor package. The water temperatures are adjustable and can be set as high as 190F. “We ordered our Z compressors with the Energy Recovery Option built in with the intent to use the hot water down the road,” says Gazda. “Right now we are running the compressors with the standard cooling method. We calculated that there are about a half million BTUs available in these machines that we will be able to use for hot water, sanitation water, building heat or pre-heating an oil boiler. These opportunities currently exist in our plant and we plan to start feeding them as soon as we can apply the appropriate engineering resources to the task. Ordering the machines today with Energy Recovery means that we don’t have to design and purchase an entire recovery system down the road. We simply have to turn on the option in our compressors and then connect to our applications.” The net result of Energy Recovery implementation will be a reduction of natural gas consumption, yet another step on the sustainability path at Gorton’s. “National Grid is also our gas supplier and they have incentive programs for gas conservation projects as well,” says Gazda. “They have stated their willingness to participate financially in the project and we can’t wait to allow them to.” Gorton’s investment in oil-free air is already improving productivity, reducing operating expenses and supporting the company’s ongoing efforts in sustainability. “Now we have very efficient, very reliable compressors plus a maintenance package, so we’re pretty autonomous,” Gazda concludes. “I would totally recommend Ron Whelan and Atlas Copco. I already have.”
The Z/MD package provides Class Ø oil-free air, which is so important in food processing. You just don’t want the risk of lubricating oil contaminating food.
Gorton’s was founded in 1849 in Gloucester, Massachusetts, America’s oldest seaport. Today, Gorton’s is committed to protecting and enhancing the sustainability of seafood resources and is working actively to support this under its Trusted Catch program. Trusted Catch encompasses all of Gorton’s sustainability initiatives, from sustainable seafood sourcing to other green efforts including a more efficient plant and distribution network.
A leader in innovation, Gorton’s was the first to develop a frozen convenience food: Gorton’s Fried and Frozen Codfish Fillets.