Because food manufacturing facilities use a lot of compressed air (particularly for conveyance and packaging lines), often run three shifts and have a need for boilers, they are often a perfect fit for compressed air heat recovery applications.
Atlas Copco recently explored the heat recovery possibilities for a food manufacturer who produces products for the retail trade and restaurant industries. This was the solution.
First, it was imperative for the facility’s compressed air to be generated by oil-free compressors in order to rule out any possibility of contamination with oil. Because ZR compressors from Atlas Copco are all ISO 8573-1, Class 0 certified, they were a perfect fit.
Second, based on an exact measurement of the facility’s required 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 percent of the input electric power. The recovered energy reduces the food company’s natural gas consumption and at the same time promotes climate protection, as less carbon dioxide enters the atmosphere. The new compressors were housed close to the boiler house – meaning one heat exchanger was sufficient.
Third, we looked at how we can increase efficiency even further. And, the answers were simple. To increase the efficiency of the compressed air generation, we installed the Atlas Copco ES energy-saving control and monitoring system.
We also installed adsorption dryers from the MD series to ensure that a pressure dew point of -30°C is always achieved. Because some lines ran outside and in refrigerated areas, it was even more critical to maintain a stable pressure dew point to ensure that water does not condense in the compressed air system and put the valves and cylinders at risk. The rotary drum dryers also use the hot compressed air to regenerate the desiccant, and therefore do not need any extra energy.
Would you like to learn if your facility is a good candidate for a compressed air heat recovery application? Please contact us for an evaluation.
