Three-dimensional simulation of fluidized bed coal gasification

A comprehensive three-dimensional numerical model was developed to simulate the coal gasification in a fluidized bed gasifier. Both gas-solid flow and chemical reactions were considered. The gas phase was modeled with k − ɛ turbulent model and the particle phase was modeled with kinetic theory of granular flow. Coal pyrolysis, homogeneous reactions and heterogeneous reactions were considered. The reaction rates of homogeneous reaction and heterogeneous reaction were determined by Arrhenius-Eddy dissipation reaction rate and Arrhenius-diffusion reaction rate, respectively. Simulations were carried out in a fluidized bed coal gasifier with a height of 2.0 m and a diameter of 0.22 m. Flow patterns, gas velocities, particle velocities, composition profiles of gas product and distributions of reaction rates were obtained. Some calculated values were compared with experimental data. The results showed that the predicted exit gas compositions were in a good agreement with the experiments. This indicates that the current three-dimensional models and simulations are successful, which provide a promising way to simulate the coal gasification in fluidized beds.