Analysis Of Corrosion Characteristics And Influencing Factors Erosion Of Furnace Tube In Steam Boiler

The steam injection boiler is the main steam injection equipment of the oil field,and the high temperature and high pressure high dry steam is produced.The heavy oil is heated by injecting the gas into the reservoir to reduce the viscosity of the heavy oil to increase the fluidity of the heavy oil,to improve the recovery factor of heavy oil.The high temperature steam in the boiler tube and the falling corrosive products and the solid particles in the water supply form a vapor-solid two phase flow,which constantly erosion and corrosion the corrugated elbow wall,resulting in the failure of the elbow wall thickness loss and is not conducive to the safe production operation of the steam boiler.In this paper,for the phenomenon of erosion and thinning of the furnace elbow,based on the theory of vapor-solid two phase flow,using FLUENT of computational fluid dynamics software CFD to numerical simulation.The calculated results are compared with the damage location of the elbow,and the effectiveness of the calculation model is verified.The influence factors of erosion corrosion are analyzed,and revealed the influence of steam speed,particle phase and elbow structure on the erosion change of elbow.The results show that with the change of particle size and steam flow velocity,the position of the maximum erosion point of the elbow is changed,mainly distributed between the angle of the elbow 130~180o,near the center of the outer ring of the elbow.Steam speed is the main influence factor of erosion,and the erosion rate of the elbow will increase with the increase of steam speed.The erosion rate of elbow increases with the increase of particle size.When the velocity is less than 36.8m /s,the particle size has little effect on the erosion rate.The increase of particle content increases the probability of particle collision wall surface,and the erosion rate will increase.Analyze the change of elbow erosion degree and predict the elapsed time of elbow erosion.The increase of bend diameter ratio will change the direction of fluid flow in the elbow,and the erosion rate will be reduced.In this paper,four measures are proposed for the elbow erosion corrosion: elbow erosion resistant material selection,selection of elbow with large radius of curvature,wall thickness detection and corrosion inhibitor protection measures.This research can provide theoretical support for the research of the corrosion resistance of the furnace tube elbow and the failure prediction of the equipment parts in the field.