A Discrete-Continuous Method for Predicting Thermochemical Phenomena in a Cement Kiln and Supporting Indirect Monitoring

Thermochemical phenomena involved in cement kilns are still not well
understood because of their complexity, besides technical difficulties in achieving direct
measurements of critical process variables. This article addresses the problem of their
comprehensive numerical prediction. The presented numerical model exploits
Computational Fluid Dynamics and Finite Difference Method approaches for solving the
gas domain and the rotating wall, respectively. The description of the thermochemical
conversion and movement of the powder particles is addressed with a Lagrangian approach.
Coupling between gas, particles and the rotating wall includes momentum, heat and mass
transfer. Three-dimensional numerical predictions for a full-size cement kiln are presented
and they show agreement with experimental data and benchmark literature. The quality and
detail of the results are believed to provide a new insight into the functioning of a cement
kiln. Attention is paid to the computational burden of the model and a methodology is
presented for reducing the time-to-solution and paving the way for its exploitation in quasireal-time,
indirect monitoring.