Fluidized bed combustion offers key advantages such as high efficiency, environmental friendliness, fuel flexibility, and load adaptability, making it suitable for various applications such as power generation, biomass gasification, and petrochemical processing. This study presents a numerical investigation of the gasification processes in a pilot-scale fluidized bed gasifier using a 3D computational model. The model simulates the complex turbulent multiphase flow within the real gasifier geometry of the pilot plant and focuses on the interactions between air and sand, as well as the temperature distribution. Initial numerical results show good agreement of fluid flow structure with experimental data. Future work will include combustion modeling, with the numerical results to be validated by experiments in the pilot plant. After model validation, the model will be used for similarity analysis to optimize the process parameters.