A clever arrangement of thermal process within the evaporation and in connection with other plants reduces consumption of primary energy drastically
The new plant design for the dealcoholisation of beer with Wiegand technology using a mechanical vapour recompressor saves more than 50 % of energy compared to conventional process designs.
Challenge in terms of sustainability:
Non-alcoholic wheat beer and other alcohol-reduced beverages are the trend. In the production usually thermal separation processes such as for example evaporation and distillation are used. Usually, the evaporators are directly heated by live steam, and therefore are energy-intensive processes. The consumption of primary energy can be drastically reduced by a clever arrangement of the thermal process within the evaporation and in connection with other plants.
Under steady-state operating conditions of the directly heated evaporation plant, 1 kg/h of live steam will be required for 1kg/h of water evaporation. In multi-effect plants, the ratio is reduced accordingly. A 2-effect plant now requires only half of the live steam for the same amount of water evaporation since the evaporated vapour of the first effect is used to heat the second effect. Today, evaporation plants for the dealcoholisation of beer are designed as multi-effects plants depending on the capacity, but in all cases the evaporated vapour flow will subsequently condense and its energy contents will thus be lost to a large extent.
Mechanical vapour recompression allows to return this energy flow into the process compressing the vapour to a higher pressure and thus to a higher energy contents. The vapours are returned into the heating chamber of the evaporator where they condense on the evaporator tubes. The energy released during this process indirectly heats the product. Such a plant does not require any live steam during operation any more, but only a considerably small amount of electrical energy for the compressor. In addition, single-stage centrifugal fans are used as vapour recompressors to further minimize energy consumption. The specific energy requirement of a falling film evaporation plant with mechanical vapour recompression amounts to 8 to 30 kWh per 1000 kg of evaporated water, depending on the specific application - which at any rate is at least 50 % less than the energy requirement of conventionally heated plants. This plant design has long been state-of-the-art for evaporation plants for liquid food products. The special challenge of the use of this technology for dealcoholisation is the high volatility of alcohol as well as the presence of inert gases (e. g. carbon dioxide) that impede the complete condensation of the vapours in the heating chamber. For this reason, the use of mechanical vapour compression, in particular with fans, was difficult and uneconomic in this case. With the new technological design by Wiegand it is possible to recover heat from the evaporator vapours in an energy-efficient manner so that they can be reused to heat the evaporator. GEA Wiegand filed the patent application for the new design.
The new plant design with mechanical vapour recompressions saves more than 50 % of energy compared to conventional processes. Energy consumption, and thus the environmental impact are reduced thanks to the use of mechanical vapour recompression.
Moreover, the dealcoholisation process in evaporation plants with temperature-sensitive treatment ensures an alcohol-free beverage product which is perfect in terms of taste and flavour. In its magazine, edition 06/2010, the German consumer association Stiftung Warentest recognized and nominated a non-alcoholic wheat beer produced with Wiegand technology as the test winner.
Brief profile of the company:
Name: GEA Wiegand GmbH
Head office: Ettlingen
Year of foundation: 1948
Number of employees: 210
Solutions: GEA Wiegand is one of the prominent manufacturers of plants of thermal-mechanical process engineering with core competences in evaporation, distillation, membrane filtration, gas scrubbing and steam jet pumps and vacuum systems.
The range of delivery and services includes consultation, planning, calculation, design, manufacture, delivery, quality control, commissioning and after sales service, plant extension and energy optimization.
GEA Wiegand has its own research and development centre with numerous laboratories and pilot plants.
Internationality: The company, incorporated in the GEA Group AG, sells its products world-wide via a well-organized network of own societies, sales offices and agencies.