Efficient steam generation at NÖM dairy
Due to production extension at the Baden location in Austria, the NÖM dairy has a higher steam demand. Every day they process about a million litres GMO-free milk into fruit yoghurts, fruit drinks and many other dairy products. The amount of energy needed for pasteurising, ultra-high temperature heating, cleaning and sterilisation is high and a reliable process heat supply is crucial for these processing steps. Achieving the best possible energy efficiency was the aim when extending the steam supply, not only because of energy costs, but also for the protection of the environment.
The energy plant at NÖM comprised two boilers. One of it had to be removed in order to make room for a larger steam boiler. It came from the Bosch factory in Gunzenhausen (Germany) and can provide up to 14,500 kilograms of steam per hour. Already for the last steam generator in 2010 the same boiler type was selected, at that time still branded Loos (today Bosch). This steam generator is now mainly used for supply reliability and assures uninterrupted production during service and maintenance work on the new steam boiler. Thanks to excellent coordination of the responsible plant engineering company Edtmayer Systemtechnik, the implementation of the identical boiler type in the existing steam network went very smoothly. A special challenge was however the positioning due to restricted space in the buildings at the Baden location. The boiler, which measured 7.5 metres long and 3.2 metres wide, was inched between two concrete pillars and then gradually turned into the boiler house.
In order to provide the steam for the dairy in an efficient way, the Bosch boiler is equipped with two flue gas heat exchangers. The first integrated economizer uses the hot flue gases from the boiler to preheat the feed water very effectively. Consequently, the fuel consumption for steam generation is reduced and the flue gas temperature decreases to 115 °C. In addition, the downstream condensation heat exchanger uses the condensation heat of the flue gas for heating the cold fresh water from 12 to 85 °C. Up to 6,100 litres of water per hour can be heated in this way. Air contaminants, such as carbon dioxide and nitric oxide, are reduced to a minimum at all operating points. Furthermore, the modern natural gas burner operates with very low emissions and covers even partial load ranges efficiently. Comprehensive support provides the fully automated control for 72 hour operation without constant supervision. It reduces the operation effort and protects against possible operating errors. In addition, the control evaluates important boiler system data – for a preventively and efficient plant operation.
In summary, the new steam boiler system enables economical and sustainable milk processing. The efficiency-increasing components help to reduce fuel consumption and protect the environment by considerably minimsed CO2 emissions. Gerhard Bartak, the project manager responsible at NÖM dairy, is very satisfied with the installation: