Demonstration plant calcining process magnesite
STYROMAG Steirische Magnesitindustrie GmbH, located in Tragöß-St Katharein, Styria, Austria, has been producing magnesium oxide (MgO) since 1870. In 1985, the first and still only fluidized bed furnace for the production of caustic burned magnesite was built.
19,000 tons are produced annually in the fluidized bed. The calcination process from magnesite to magnesium oxide takes place in the fluidized bed furnace, producing CO2 due to the production process (see Fig. 1 process diagram).
Figure 1: Process scheme
The fluidized bed process is characterized by the fact that impurities remain in the reactor as residues. In this way, a high degree of product purity can be achieved. This process takes place in the fluidized bed at around 790 ° C. The energy required for increasing the temperature and calcining is brought in by natural gas.
In 2018/2019 the idea arose to modernize this manufacturing process. In cooperation with VOIGT + WIPP Engineers, this modernization was also used for energetic optimization. Another project goal was to set a new, outstanding benchmark in terms of energy efficiency and CO2 emissions in the entire industry (see Figure 2) and to implement this as part of a demonstration project.
Figure 2: Specific CO2 emissions from process heat generation during Mg calcination
With optimization measures to more sustainability
In the existing process, heat recovery is partially implemented in a multi-stage process (raw stone preheater, exhaust gas cooler for preheating the combustion air).
The innovative energy integration optimized by VOIGT + WIPP Engineers now ensures maximum heat recovery over the entire process. Both the use of primary energy from natural gas and the consumption of own electricity can thus be reduced by approx. 20% each. Our specified advanced process control optimization measures for optimized process management should also significantly reduce CO2 emissions of 1165 tons per year.
As part of this project, in cooperation with the manufacturer, we are also developing a new type of heat exchanger that, thanks to innovative technology and robust design, can withstand the very high temperatures and extreme dust exposure. The demonstration project thus integrates solution approaches and innovations for numerous aspects of the MgCO3 calcination process.
A technology project by VOIGT + WIPP engineers
Located in the “Energy and Process Technology” division of VOIGT + WIPP Engineers, the technical concept was developed under the leadership of DI Dr.techn. Bernhard Kronberger and made ready for implementation. We were able to play a decisive role in the projects co-financing through subsidies and the project implementation through the design of the project team carries the signature of VOIGT + WIPP Engineers.
Currently (August 2020) the planning phase of the numerous conversions of the devices, units and automation is coming to an end. The next phase, the work on the construction site, is just starting and the entire conversion is being carried out in an extremely short time window of the 3-week production shutdown.
And then it gets exciting …
We will lead the commissioning of the renewed and process-technically optimized plant from the beginning of September. As VOIGT + WIPP Engineers, we not only ensure stable, safe and high-quality plant operation but also the clear goal of helping STYROMAG to play a pioneering role in MgO production in Europe.
Text: Excerpts from KPC’s 2019 annual report