Validation of a one-dimensional kiln heat transfer model against a pilot kiln

The thermal energy required for cement manufacture is primarily utilised within the rotary kiln where clinkerization occurs. To optimise this key stage in cement production, accurate kiln process models are required. In this work, a simple yet powerful one-dimensional kiln model is presented. The thermal aspects of the presented kiln model have previously been partially validated [1,2]; however, new data from trials in a 7-meter pilot kiln are used to validate the thermal model at scale in the development of a novel C$A cement formulation. This process is challenging as it requires careful atmospheric and temperature control. A thermodynamic database is used to calculate the thermal properties of the gas and solid. Gibbs free energy minimisation is used to predict the stable phases at each stage within the process. The developed model is fully predictive and only the kiln configuration, fuel, excess air, and solid inlet composition are required as inputs. Even without an accurate flame model, the model presented accurately tracks the external and produced solids temperatures. The model is then used to successfully diagnose production issues and demonstrates its value in redeveloping the cement process.