engleski

Numerical modelling of pulverized coal combustion for a cleaner cement production

Combustion of pulverized coal is a very important mode of fuel utilization in cement industry. In addition to the influence on cement quality, pulverized coal combustion also affects the overall energy efficiency of the cement manufacturing process and the pollutant formation. One possibility for the control and investigation of the pulverized coal combustion process is CFD simulation. Early comprehensive information, parametric studies and initial conclusions that can be gained from CFD simulations are very important in handling modern cement technology requirements. Together with experiments and theory, CFD has become an integral component of cement pyroprocessing unit‘s research. It has been used in the development process for understanding the complex phenomena occurring within the pyroprocessing units. For instance, results gained from CFD simulations of the pulverized coal combustion in the calciner can be used for the optimization of a calciner operation and design, increasing the final cement quality, improving fuel consumption and reducing pollutant emissions. In order to study the role of pulverized coal combustion during the cement manufacturing process, appropriate pulverized coal combustion numerical model needs to be used. In this study a numerical model of the pulverized coal combustion was developed and a three dimensional geometry of an experimental furnace was simulated with a commercial finite volume based CFD code FIRE. This code was used to simulate turbulent flow field, temperature field, concentrations of the reactants and products as well as the interaction of particles with the gas phase, by solving the set of mathematical equations, which govern these processes. Time-averaged conservation equations were solved for the gaseous and particulate phase, the former being treated by the Eulerian formulation, and the latter by the Lagrangian formulation. To verify the accuracy of the modelling approach, the numerical predictions were compared with experimental data, yielding satisfying results and proper trends for the pulverized coal combustion as well as for the calcination. Thus main components for plant simulation and optimization are available. Based on this applicability of the coupled models in a realistic calciner plant has been demonstrated.

numerical modelling; pulverized coal; combustion; cement production

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