In this paper, numerical calculation and optimization research are carried out in view of the composite settlement characteristics of oil field wellhead casing during catalytic cracking reaction. By establishing a multi-dimensional, multi-phase and heterogeneous numerical model, the key processes such as mass transfer, heat transfer and chemical reaction are comprehensively considered, and the composite sedimentation model is introduced to accurately describe the sedimentation behavior of particles in the fluid. Genetic algorithm (GA) is adopted as the optimization algorithm, and the objective function is designed to maximize the yield of light oil while minimizing the energy consumption and coke yield. The calculation results show that the temperature and concentration distribution in the reactor show a significant gradient change, and the composite sedimentation characteristics have a dual impact on the catalytic cracking reaction, which may not only lead to the decrease of the reaction rate and the increase of coke selectivity due to the local accumulation of catalyst particles, but also improve the heat transfer efficiency by forming a dense bed. The optimization results show that the yield of light oil is increased from the initial 38% to 45%, and the yield of coke is reduced from 12% to 8%, which significantly improves the economy of product distribution. The experimental data show that the model can accurately predict the key parameters in the reaction process. Although there are some errors, the prediction accuracy can be further improved by improving the model assumptions, improving the experimental accuracy and optimizing the weight coefficient adjustment method. This study provides guidance for wellhead casing design in many aspects, including optimizing reactor structure, dynamically adjusting operating parameters and prolonging catalyst life, which is expected to increase economic benefits by 12-15%.
