CFD modeling of rotary cement kilns

Abstract

Rotary cement kilns are widely used to convert calcineous raw meal into cement clinker, and are key components in the cement industry. In this article, we report a comprehensive computational fluid dynamics (CFD)‐based model to capture key transport processes in rotary cement kilns. Separate but coupled computational models were developed for the bed and the freeboard regions of the rotary kiln. The complex swirling airflow produced by kiln burners, coal combustion, gas‐phase combustion of volatile matter and radiative heat transfer in the freeboard region were modeled. The clinkerization reactions in the bed region were modeled assuming solids as pseudo fluids. Coating formation in cement kilns (for both bed and freeboard regions) was considered. Appropriate source and sink terms were developed to model transfer of CO2 from the bed to the freeboard region due to calcination reaction in the bed region. The developed bed and freeboard models were coupled by mass and energy communication through common interface. These coupled computational models were able to quite satisfactorily predict the available data from industrial kilns and previously published results. The computational models were also able to capture the intricacies of the burning zones of rotary cement kilns for changing burner‐operational parameters like axial to swirl ratio and oxygen enrichment. The developed approach, computational models and simulation results will not only help in developing better understanding of cement kilns but also provide quantitative information about influence of burner design and other design parameters on kiln performance. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

“…In the past decades, modeling and numerical simulation have been used to provide a detailed insight and quantitative guidelines for reactor design and optimization. However, existing work for rotary kilns focuses on the flow field [7][8][9], mixing/segregation [10][11][12][13], and heat transfer performance [6,14,15]; simulation of chemical processes in a rotary kiln is still in its infancy due to the complexity of coupling of dense gas-solid flow, heat transfer, and reactions [16]. There are only few modeling researches concerning the reacting flow for rotary kilns, which can be categorized two types.…”

“…Babler et al [18] developed a modular numerical model for biomass pyrolysis in a rotary kiln, which considered the solid bed region and gas phase domain at steady state. Mujumdar and Ranade [16] developed separate but coupled computational models for bed and freeboard regions for rotary cement kiln. The reactions in the bed region were modeled through single-phase pseudo fluid, and combustion of coal particles in the freeboard region was modeled by Eulerian-Lagrangian approach.…”

Intensifying Multiphase Reactions and Reactors: Strategies and Examples

“…For example, Ranade and Gupta [116] have demonstrated use of CFD models to enhance performance of pulverized coal fired boilers. Mujumdar and Ranade [117] have shown how reaction engineering and CFD models can be coupled to enhance performance of cement kilns. Similar models were also used to intensify kilns used for manufacturing hydrofluoric acid (HF).…”

CFD Modeling of Meat and Bone Meal Combustion in a Rotary Cement Kiln

“…Bed and gas temperature, clinker composition and factors affecting the overall energy consumption have been analyzed and the model has been used to simulate performance of three industrial kilns. Since a 1D model cannot catch the influence of burner design and key operating parameters such as axial:swirl ratio, oxygen enrichment, coal particle size and ash content on flame characteristics, FLUENT has been used to couple models for the bed and freeboard regions [22]. Also, an integrated reaction engineering based mathematical model and a software (RoCKS) has been developed for the whole kiln system by same authors [23].…”