Study On Liquid-solid Flow Wear Characteristics Of Non-spherical Catalyst Particles In Tube Based On CFD-DEM

A petroleum refinery’s fluidized bed residue hydrogenation unit is a vital piece of equipment.However,due to the corrosion failure of the catalyst particles during transportation in the tube,this unit has resulted in significant losses.The majority of research on liquid-solid flow wear by domestic and international scholars is focused on the assumption of spherical particles.The columnar morphology of catalyst particles can change their trajectory and affect flow and wear characteristics as compared to spherical particles.As a result,understanding and mastering the flow and wear characteristics of non-spherical particle liquid-solid two-phase flow in the pipeline would assist in reducing the corrosion risk of the addition and discharge pipeline,as well as ensuring the safe and stable operation of the fluidized bed hydrogenation unit.The hydrogenation catalyst addition and discharge device of a refinery is the research object of this paper,which analyzes the liquid-solid two-phase flow and wear characteristics of the non-spherical catalyst particles in the tube using experimental and numerical simulation methods.The following are the key research findings:(1)The multi-ball cluster approach is used to build the geometric model of the columnar particles based on experimentally determined data.A CFD-DEM mathematical model and prediction system suitable for liquid-solid two-phase flow wear in the columnar form catalyst particle tube was built using the required particle collision wear model and drag force model.(2)The liquid-solid two-phase circulation experiment platform was designed to show the flow and wear characteristics of columnar particles in the liquid-solid two-phase flow tube: increasing particle flow rate would increase the wear rate of the outer wall;the most serious erosion wear rate is located to the outlet,followed by the outlet section close to the center of the elbow.The main abrasion of particles on the elbow is composed of micro-cutting wear and deformation wear,of which micro-cutting scratches are mainly distributed on the wall surface at a low angle of15°～45°,deformation and wear;the main abrasion of particles on the elbow is composed of micro-cutting.It’s mostly found in pitting pits created by the impact on the wall at a higher angle of 65°～90°.Experiments have also shown that mathematical model calculations are applicable to this study.(3)By Analyzing the catalyst transport pipeline at the residual oil hydrogenation unit’s inlet for structure and process flow,the elbow is found to be the most worn pipe in the numerical prediction of two-phase flow wear characteristics in the inlet pipe,and the wear region is concentrated on its outside wall.The maximum erosion rate is used to determine the danger degree of each elbow.The law of pipeline erosion and wear under various influencing factors is also discussed in the study.Using the gray correlation process,the degree of correlation between influencing factors and erosion and wear is sorted,and the original pipeline system is optimized and compared.The findings show that the maximum wear rate is decreased by approximately 24.7 %at the highest level,and at least 10.5 % at the lowest level,suggesting that the optimization effect is more evident.The following are the paper’s special features:(1)A geometric model of columnar particles was built based on experimental results,the shape factor of the drag force model was updated,and a mathematical model suitable for the analysis of the flow and wear characteristics of catalyst particles in the tube was constructed.As well as forecasting techniques.(2)The correlation model between multiple erosion and wear influencing factors and the maximum erosion rate of the pipeline is built using the gray correlation analysis process,and the erosion resistance structure of the inlet pipeline is optimized.