Entwicklung eines automatisierten Qualitätssteuerungskonzepts zur Rohmehlproduktion in mischbettlosen Zementwerken unter Einsatz variabler Ersatzrohstoffraten

The cement industry faces the challenge of becoming climate-neutral by 2050. A central approach to reducing the CO₂ emission factor of clinker is the increased use of CO₂-reduced alternative raw materials (ARM). This dissertation developed an automated quality control concept for raw meal production in cement plants without targeted large-scale homogenization options. The overarching goal was to design a proactive process control system that ensures specification-compliant raw meal quality with high uniformity and minimal material and CO₂ emissions costs, even with increased ARM usage. The development was carried out at the Wietersdorf cement plant of Alpacem Zement Austria GmbH.
The concept was developed in two phases: First, an Excel-based simulation was conceptually developed, then implemented as a web-based software with automated interfaces, allowing full automation and continuous integration into the production process. The required process analysis data mainly comes from inline analyzers. The developed process control system integrates, in addition to silo modeling and recipe optimization as core components, a mass balance for trace elements all the way to the final cement product, ensuring compliance with both process-critical quality parameters and regulatory requirements for increased ARM usage.
The evaluation of the control concept was carried out in three stages. In the Factory Acceptance Test (FAT), the Excel-based simulation was tested under industrial conditions during the first “On TrACK” trial, where the stability of the lime standard in the raw meal, a central quality parameter, was successfully demonstrated even with an ARM rate of 45%. The "On TrACK" trial series at Alpacem Zement Austria GmbH aimed to expand the existing industry standards for ARM use in clinker production. In the Site Acceptance Test (SAT), the functionality of the web-based software was validated during a one-month test production under real operational conditions with an industry-standard ARM rate of 10–15%. The results showed a significant improvement in quality consistency compared to manual recipe control. In a final performance evaluation of the process control over a multi-month observation period, the functionality was demonstrated by the system's high efficiency and stability both under standard conditions and with maximum ERS utilization in the second "On TrACK" trial.
The scientific contribution of this dissertation lies in the functional and structural design of the control method in combination with the design of the process analytics, providing an innovative solution to the specific challenges of sustainable raw meal production. The developed approaches not only lay the foundation for the increased use of ARMs but also make a significant contribution to the sustainable reduction of CO₂ emissions in the cement industry. The developed process control system is transferable to other cement plants with similar plant topologies and process analytics configurations, enabling broad applicability across the industry.