Reconstruction of Pore Structures in Petroleum Coke Packed Beds Utilizing CT Scanning and CFD Simulation of Resistance Characteristics

During the calcination of petroleum coke in a vertical shaft calciner, the particle packing structure exerts a decisive influence on the bed resistance characteristics and further significantly affects the devolatilization efficiency. This study employs three-dimensional computed tomography (CT) scanning technology to digitally reconstruct the pore structure of a packed bed of petroleum coke particles. Moreover, a computational fluid dynamics (CFD) simulation model is developed to simulate gas flow at the pore scale within the packed bed. A systematic analysis is conducted on the influence mechanisms of various factors, including particle size, gas velocity, gas composition, temperature, and bed length, on the gas flow resistance characteristics within the bed. The research findings indicate that the porosity of the packed beds of petroleum coke particles with different sizes ranges from 38.7% to 52%. The pore size within the bed exhibits a positive correlation with particle size, and gas migration predominantly occurs through slit flow. Under identical inlet gas velocity conditions, smaller particle sizes result in higher maximum gas velocities and greater unit pressure drops within the bed. At low gas velocities (e.g., 0.01–0.06 m/s in this work), both the maximum gas velocity and maximum pore pressure demonstrate a significant linear increase. The various factors exhibit different degrees of influence on the unit pressure drop, with particle size having the most significant impact, followed by gas velocity, then temperature, and finally gas composition. Consequently, the relevant research findings provide crucial theoretical support for optimizing the calcination process in vertical shaft calciners, expanding the range of raw material adaptability, and reducing production energy consumption.