Improving the sustainability of cement production by using numerical simulation of limestone thermal degradation and pulverized coal combustion in a cement calciner

The cement industry sector is one of the largest carbon emitting industrial sectors, and due to the effect of global warming sustainable cement production is increasingly gaining on importance. Controlling the combustion of coal and the thermal degradation of limestone, the two main thermo-chemical processes that occur inside a cement calciner, is of significant importance, since these processes have a direct influence on the cement quality, pollutant formation and overall energy efficiency of the cement manufacturing process. One of the possibilities for the improvement and control of these thermo-chemical processes are Computational Fluid Dynamics – CFD simulations. The results gained from these simulations are being increasingly used to enhance the efficiency of cement production, since they improve the understanding of the flow characteristics and transport phenomena taking place inside the cement calciner. The purpose of this paper is to present that a more energy efficient and sustainable cement production can be achieved by deploying CFD simulations in the process of cement production. The numerical models of limestone thermal degradation, also known as the calcination process, and pulverized coal combustion were developed and implemented within the commercial computational fluid dynamics code FIRE, which was then used for the analysis. The developed models are based on the solution of Navier–Stokes equations for the gas phase, and on the Lagrangian dynamics for the discrete particles. A three dimensional complex geometry of a real industrial cement calciner was used for the CFD simulation. The information obtained from this numerical simulation, such as the distribution of particles, distribution of temperatures and the concentrations can be used for better understanding of particle kinetics and pollutant emissions from the given cement calciner and also for its further investigation and optimization.