A Study On Top Cooling System Of High Acid Crude Oil Direct Catalytic Cracking Tower

Application of complete set of technology for direct catalytic cracking of high acid crude oil in industry has solved the problem of corrosion of high sour crude oil for conventional processing.But in the practical application process,the corrosion behavior of catalytic cracking tower cooling system is more serious.The corrosion of the top cooling system mainly includes pitting corrosion,corrosion,crevice corrosion and erosion corrosion,etc.,in which the pitting perforation is the main type of the failure of the catalytic cracking tower cooling system.The causes of equipment material pitting perforation were analyzed,and the main factors affecting the corrosion of the catalytic cracking tower top cooling system were p H value,chloride ion,sulfur ion,temperature and oxygen content.The corrosion resistance of316 L stainless steel was selected,and the influence of corrosion environment on the corrosion behavior was studied in the simulated solution.This provides a reference for the corrosion protection of the system.Orthogonal test was carried out on the main influencing factors of temperature,p H value,Cl-concentration and S2-concentration.Polarization curves and AC impedance spectra are obtained.Polarization curves are analyzed,the corrosion potential and corrosion rate of the curve were obtained by fitting,and the parameters such as the current density and the pitting potential are obtained by analyzing the data.The results were analyzed by range and variance,and the factors influencing the magnitude and significance of corrosion behavior were judged.By means of AC impedance spectroscopy,the range and variance of Rs,R1 and Y0 were analyzed.Determine the magnitude and significance of each factor for corrosion behavior.Experimental study on the influence of various factors on the corrosion of the tower top system,the influence of various factors on corrosion potential and corrosion rate of the materials was determined by comparing the results of polarization curves,judging corrosion resistance and corrosion mechanism of metallic materials in various environments.Recommendation to strengthen the S2-concentration,Cl-concentration of on-line monitoring,appropriate to adjust the p H value slipped out of solution and reduce the water content and other measures to reduce the high acid crude oil directly overhead cooling systemcorrosion cracking behavior.