FOCUS. Sophisticated system technology for freeze-drying. Reference for food industry EFFICIENT REFRIGERATION TECHNOLOGY IN ACTION

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1 FOCUS Reference for food industry Sophisticated system technology for freeze-drying EFFICIENT REFRIGERATION TECHNOLOGY IN ACTION

2 Sophisticated system technology for freeze-drying Freeze-drying: a four-stage cascade coupled by use of control technology from -70 to +85 C NaProFood Freeze-drying is an especially gentle process which is used with milk, for example. The loose milk granules contain all the valuable ingredients of untreated milk. In Bruckberg (near Munich), there is a refrigeration system which is probably unique. At the factory of NaProFood GmbH & Co. KG, which specialises in (freeze-)drying high-quality foods and pharmaceutical ingredients, this system not only generates the desired low temperatures with high precision, but also heat for the engineering processes. Overall, four refrigerant circuits with four different refrigerants are cascade-connected here generating temperatures from -70 to +85 C. NaProFood GmbH & Co. KG is undoubtedly a specialist in food processing. Its systems and drying processes come into use when only unsatisfactory results are obtained with conventional drying methods. Dr. Claudia Holley, Managing Director and co-owner of the company, has been working on this subject for many years: Among other methods, we use the freeze-drying process, which allows an especially gentle drying of food and related products. 2 FOCUS

3 NaProFood The freeze-drying systems form the heart of the new NaProFood location. Gentle drying an interesting process This is an interesting process. First, trays are filled with the material to be dried and it is then frozen. The free water components then exist as ice crystals. Under vacuum conditions, the frozen water goes directly into the gaseous state if the product is slightly heated, but still remaining in the cryogenic range. Thus the liquid state is skipped. The bound water fractions are removed in subsequent drying by further slightly increasing the temperature of the product while decreasing the vacuum. It is thus a temperature-controlled process which takes a relatively long time. The user is rewarded by the fact that the desired ingredients, such as aroma, flavours, hormones and immunobiologicals are retained although the water contained in the raw material is removed as steam. The result of the process is a dry product with a long shelf life and only a fraction of its original weight. New factory, new technology Among the products which NaProFood dries in this way are various types of special milk, such as mare s milk, which is used for cosmetic products, and so-called beestings, or colostrum. This is the milk from the first milking after calving. It has a high proportion of antibodies and is used by the pharmaceutical industry. NaProFood also dries fruits and various vegetables at the behest of their customers. Dr. Claudia Holley: The need continues to grow. For this reason, the company moved to new premises on a greenfield site a few months ago and put two new freeze-drying systems into operation. 3

4 Sophisticated system technology for freeze-drying Freeze-drying: a four-stage cascade coupled by use of control technology from -70 to +85 C NaProFood Freeze-dryer in action: a look inside Sophisticated system technology with sustainable energy use Such systems cannot be bought off the shelf; they are individually planned. In this case, a collaborative effort was involved, with NaProFood (where the system and process parameters were defined), SPX Flow Technology Warendorf GmbH (the main contractor and a specialist in process engineering) and L&R Kältetechnik GmbH & Co.KG. Under the brand name e&e series, SPX Flow Technology develops systems for extraction, evaporation, vacuum- and freeze-drying, which are used in the food, pharmaceutical, cosmetics and beverage industries. In the field of refrigeration, the company has been working for years with L&R Kältetechnik GmbH & Co. KG, which was also commissioned with the planning and installation of refrigeration systems in this project. Cold and heat in various temperature ranges Overall, NaProFood systems need heat or cold in very different temperature ranges. But first, here is a description of the two refrigeration circuits: The two cryogenic refrigeration systems, with the refrigerants R 507 and R 23, provide process cooling for both the cooling coils in the ice condenser in which the water removed from the process condenses and for the simultaneously activated plate heat exchanger in the product chamber circuit. 4 FOCUS

5 NaProFood Ready for drying: milk ice granules on a tray Granulation of frozen blocks of milk NaProFood The material to be dried is placed in trays on a rack which can be both cooled and heated. This allows for precise temperature control during the drying process. In the product chamber circuit, a thermal oil circulates through plate-like cooling/heating elements which are arranged directly under the trays in which the material to be dried is located. Depending on whether heat is to be removed from the process or added to it during the drying process, Baysilone is cooled by the heat exchanger of the refrigeration system or heated by a second heat exchanger. Only in this way it can be ensured that the water in the product moves directly from the solid phase to the gaseous phase. The resulting steam is removed by the vacuum pump into the ice condenser, where it condenses to ice and is stored. Two power-controlled refrigeration systems combined with heat recovery A frequency-controlled compressor is installed in the cryogenics stage of the system because the cooling demand decreases continuously during drying. In the last third of the drying process, the refrigeration system can even be completely shut off at times to take advantage of the cold buffer capacity of the ice condenser. An algorithm being able to predict the condensation requirement is integrated into the PLC thus controlling the activation and deactivation of the refrigeration system. Thus, the system always provides exactly as much cold as is needed. This saves energy. Another feature of the NaProFood thermal process technology is that both refrigeration systems are connected to a heat recovery system. The heat entering the refrigerant is used for heat recovery. For this purpose, NaProFood has set up two large storage containers: the smaller one provides medium-temperature storage for 60 C warm water, while the larger one provides high-temperature storage at 85 C. 5

6 Sophisticated system technology for freeze-drying Freeze-drying: a four-stage cascade coupled by use of control technology from -70 to +85 C The speed-controlled refrigeration compressors and pumps allow cold generation to be adapted to current needs. The heat pumps which supply these two circuits are filled with the refrigerants R 134a and R 236fa. They provide so much heat that NaProFood can cover more than 80% of its thermal process energy requirements in normal operation. The freeze-dryer itself, the vacuum drying system, the central hot water system and the CIP system, as well as numerous smaller consumers, are supplied with the recovered heat. The heat pump compressors are also controlled by frequency inverters, so that the currently generated heat power is brought to the higher temperature level in a manner being optimal in terms of energy. An energetically closed circuit with four temperature levels The cooling or heating technology thus represents an energetically closed circuit providing cold and heat in the range between -70 and +85 C. This is ensured by four separate systems two chillers and two heat pumps which are connected using intelligent controllers. All the stages are equipped with speed-controlled drives to allow optimal adaptation to the current operating conditions, and thus low energy consumption. It is obvious that this system is extremely complex in terms of the controllers. The planners at L&R have brought their extensive know-how into the design of the processes to ensure that the four thermal processes really do mesh optimally. The controller-related competence of the company, which builds its own switch cabinets and has its own programmers, ultimately helped to ensure that the desired temperature can be reliably attained in any system status. The necessary transparency is also guaranteed, as the processes and the current operating status of the system are displayed on the man-machine interface. 6 FOCUS

7 L&R facts L&R KÄLTETECHNIK GmbH & Co. KG D Sundern-Hachen Hachener Straße 90 a T F info@lr-kaelte.de Core competencies / activities Since it was founded in 1991, the company has developed an outstanding expertise in refrigeration technology, with a focus on the environment- and energy-conscious use of powerful and high-quality refrigeration systems. In close cooperation with its clients, L&R Kältetechnik develops energy-efficient overall concepts whose long-term effects attain a hitherto unparalleled efficiency. L&R provides refrigeration and temperature control systems in various models and power classes, as well as system commissioning, system inspection and the optimisation of existing facilities. The temperatures involved range from -120 C to +350 C. L&R s expertise resulting from its own switch cabinet construction is also available as a service to mechanical and plant engineering companies. Industries Plastics and rubber industry Surface technology and electroplating Food industry Chemical and pharmaceutical industry Medical technology / metal processing Control technology is one of the core competencies of L&R Kältetechnik. The close cooperation with SPX and NaPro- Food in the planning phase also guaranteed that the best results from the refrigeration and energy points of view were obtained. Conclusion: a unique (refrigeration) system In summary, it can be said that a unique thermal process system supports a fascinating process here. Four refrigeration cycles with four different heat transfer agents have been integrated in a highly complex overall process which involves additional energy, such as waste heat from the compressor. The control technology developed and programmed by L&R Kältetechnik ensures very precise temperature control at all temperature levels. 7

8 Competencies MARKKOM.COM PLASTICS AND RUBBER INDUSTRY A plastic-parts manufacturer operating about 100 injection moulding machines recorded frequent machine failures that were caused by the aging refrigeration system. Renovating the system didn't just reduce the number of failures; the improved cooling allowed the injection-moulding machines to operate with shorter cycle times, enabling our customer to increase their output by 10-15%. SURFACE TECHNOLOGY AND ELECTROPLATING An advanced refrigerant, higher cooling capacity and significant energy savings were the objectives pursued by Koenigsdorf Oberflächentechnik GmbH & Co.KG in Wolfhagen when they decided on a new refrigerating system. FOOD PRODUCTION Refrigeration is one of the main energy consumers in chocolate production. Retrofit projects can achieve savings of up to 50% an investment that gives the user a clear amortisation period. L&R Kältetechnik cooperates with two companies that specialise in this sector. CHEMICAL AND PHARMACEUTICAL INDUSTRY We have the best references in the cryogenics sector, including for the storage of blood plasma. For these particularly challenging applications, we plan and design completely redundant refrigeration systems with correspondingly high safety features. SPECIAL UNDERGROUND MINING Ground-freezing systems are becoming increasingly common in mining projects when sinking shafts. A freezing system with a capacity of 3600 KW was developed and constructed for a Russian potassium mining project which cooled cold brine to a flow temperature of -38 C. L&R Kältetechnik GmbH & Co. KG Hachener Straße 90a, D Sundern-Hachen Tel.: , Fax: DW 50 info@lr-kaelte.de L&R Kältetechnik GmbH & Co. KG Büro Frankfurt a.m. Hasengasse 4, D Maintal Tel.: , Fax: DW 875 Mobil: f.woell@lr-kaelte.de Responsible for the content: L&R Kältetechnik GmbH & Co. KG Burkhard Rüßmann; design and realisation: MARK KOM Consulting / Lindau (D); Image copyrights: L&R Kältetechnik, NaProFood