Germany’s largest and most state-of-the-art milk drying plant is located in Neumünster in Schleswig-Holstein. The production site is located between Hamburg and Kiel – in the heart of one of Germany’s largest milk production regions. Here, approximately 600 million kilograms of milk are processed into skimmed milk powder for the international food industry each year. To produce milk powder, water is removed from milk by evaporation. While liquid drinking milk consists of 87.5 percent water, milk powder contains only about three percent. A great deal of energy in the form of steam is required for the sophisticated process of producing 60000 tons of milk powder per year.
The engineering office of Herbert Hannemann, DIHH, partnered with plant manufacturer Georg Hagelschuer and Viessmann Industriesysteme GmbH to develop an energy concept for the entire plant, with the aim of achieving a high level of energy and resource efficiency. For example, part of the energy used to heat the milk is recovered. The use of fresh water is also significantly reduced through optimized processes and condensate recovery. The owners, Uelzena eG, Meierei Barmstedt eG, Meierei Wasbek eG, and Meierei-Genossenschaft Schmalfeld-Hasenmoor eG, invested a total of 64 million euros in the system.
The heart of the plant is the 50-meter high spray drying tower, one of the largest in Europe, in which the skimmed milk is dried using various steam-heated air heaters. Around six to seven liters of raw milk are needed to produce one kilogram of milk powder.
Boiler system from Viessmann for reliable steam supply
For the Neumünster milk drying plant, the main criterion in the choice of boiler and combustion technology was safe, economical, and environmentally friendly steam generation.
In the newly installed steam boiler system, two Vitomax 300-HS high-pressure steam generators create steam at a pressure of 16 bar with an output of twice 10 tons per hour. The two high-pressure steam generators with an integrated economizer meet all new legal requirements for particularly low-emission combustion. The boilers with an economizer boast an efficiency of 96 percent – even at full load.
Gas burners with digital combustion management as well as speed and oxygen control ensure efficient fuel utilization. State-of-the-art measurement, control, and feedback technology in conjunction with a PLC boiler control system provide reliable, efficient, and economical operation of the steam boiler system. The use of these modern technologies was also an important prerequisite for the ISO 50001 certification.
Over 90 percent of the condensate is returned
A large part of the energy used for heating and evaporating the milk is recovered in the form of condensate by means of steam heat exchangers. The rate of condensate return in this process is over 90 percent. This condensate is collected and fed back to the thermal full degassing system. The feed water is then fed to the steam boiler via highly efficient and speed-controlled feed water pumps. The integrated economizer increases the feed water temperature while the hot exhaust gas is cooled down to approx. 125°C. This raises the efficiency of the system and significantly reduces fuel costs.