Wernsing Feinkost needs process heat around-the-clock. The company covers part of the amount needed, 350 kW, by using compression heat from the compressed air station. How? With Atlas Copco ZR oil-free screw compressors with an energy recovery system
Wernsing Feinkost GmbH, in Addrup-Essen, produces food for the retail trade and restaurant industries. Many manufacturing plants, particularly conveyance and packaging lines, operate using compressed air, and they do this around-the-clock, since they typically run three shifts.
For Hartwig Sibbel, responsible for Environmental and Energy Management, these were ideal conditions for considering heat recovery.
“Heat is generated when the air is compressed, and compressors have to be cooled constantly. We wanted to use this heat in our boiler house to preheat soft water for steam generation, because there we can use it as process heat all year long.”
Based on an exact measurement of the compressed air consumption, Atlas Copco proposed a compressed air station with two water-cooled, oil-free model ZR 250 VSD and ZR 160 screw compressors, with a total of 410 kW installed power.
Water cooling and heat recovery go together perfectly as the cooling water, with a temperature of up to 90°C, can very easily transfer the compression energy via a heat exchanger to the heating circuit in the boiler house.
As the two compressors are used nearly to capacity, a heat power of up to 350 kW is available - this corresponds to 80 to 85% of the input electric power. The recovered energy reduces the food company’s natural gas consumption. At the same time it promotes climate protection, as less carbon dioxide enters the atmosphere.
“The cost of heat recovery was not high,” Hartwig Sibbel is happy to report. The new compressors were housed close to the boiler house, meaning one heat exchanger was basically sufficient.
To increase the efficiency of compressed air generation, even more, Wernsing also installed the ES energy-saving control and monitoring system.
Wernsing chose a product from Atlas Copco for its peripherals. Adsorption dryers from the MD series ensure that a pressure dew point of -20°C is always achieved.
“Some lines run outside and in refrigerated areas,” the Environment and Energy Manager explained. “This makes the pressure dew point even more important, so the water does not condense in the compressed air system and puts the valves and cylinders at risk.” The rotary drum dryers use the hot compressed air to regenerate the desiccant, and therefore do not need any extra energy.
For Wernsing, it was also imperative for the compressed air it required to be generated by oil-free compressors only: “We produce food and want to rule out any possibility of contamination with oil.” He can be sure of this, since the ZR compressors from Atlas Copco are all ISO 8573-1, Class 0 certified.