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Agitator retrofit boosts dairy energy efficiency

Milchwerke Oberfranken West eG is one of the leading international producers of fine cheese specialties. Located in Germany’s Coburg District, the company produces approximately 37,500 tons of a broad assortment of quality soft, hard or processed cheese preserved solely with table salt. 

To increase production of its natural cheese products produced by using microbiological rennet for fermentation of raw milk, the dairy installed a new 360,000-liter tank. Intrigued by the prospect of cost savings offered by a more energy-efficient agitator, the dairy decided to test an Alfa Laval agitator for energy efficiency, hygiene and food safety. The dairy processor installed the Alfa Laval ALS Agitator that uses only 4 kW of installed power instead of installing a conventional tank agitator with 18 kW of installed power.

The dairy began testing the agitator with a volume of 100,000 liters of milk in its newly installed tank. The volume was steadily increased to 150,000 liters, and then to full tank capacity of 360,000 liters. Samples were taken every hour to check the quality of the milk.

“The milk ingredients, especially the fat content, were checked. We detected no changes in the production line for cheese and the manufacture of the product,” says Dieter Stuerzl, quality manager for equipment, Milchwerke Oberfranken West eG. “Furthermore, we let the standardized non-homogenized milk stay in the tank for a day to see whether there were differences in the processing of raw milk using the new agitator,” Stuerzl continues. “The test agitator worked smoothly during the entire process, thereby meeting our expectations.”

After the three-month trial period, Milchwerke Oberfranken West ordered 11 new energy-efficient agitators to replace the conventional tank agitators being used.

One of the most important reasons for a dairy to retrofit existing equipment is to achieve energy savings. “If there are existing agitators running in the production process, it is often hard to imagine a restructuring,” Stuerzl confides. “Given a 220,000-liter milk tank and an 11-15 kW agitator, retrofitting to a 2.2 kW agitator is an enormous undertaking. Naturally, we are also happy to see the associated energy savings.”

The Alfa Laval ALS agitators feature specially designed rotor blades that require less energy input than conventional agitators. Reductions of up to 80% in energy consumption can be realized.

Stuerzl says that the success of the agitator retrofit project has reinforced Milchwerke Oberfranken West’s decision to carry out further energy-saving projects in the dairy. “I believe that the flow behavior and the gentle handling of the milk by the Alfa Laval ALS Agitator has had a positive effect on the product,” he confides.