Research of Heat Exchanger Tube Bundle Failure Analysis Methods and Application
|School||Northeast University of Petroleum|
|Keywords||heat exchanger tube bundle failure corrosion|
Heat exchangers are largely used in petrochemical industry, salt chemical, coal chemical,thermal power plants and other industrial systems. Because the heat exchanger tubes contactcomplex media whose traits are high pressure(2500MPa), high temperature(nearly1000℃),strong corrosion and high speed in the production process, corrosion leakage and scourleakage always occur. A variety of corrosion and leaks have direct or indirect relationship.Tube bundles are the most easily damaged parts of the heat exchangers. the main formsof tube bundle failure are tube cracking leakage, the decline of heat transfer capability powerincreasing in fluid transport, noise and so on. Analysis of the reasons, there are threeinduction factors: corrosion, shake and scaling. Based on the failure reasons of heat exchangertubes, failure modes, the basic theory of the corrosion mechanism, combining with the basictheory of the failure analysis, analytical thinking, and analytical procedures, ideas andprocedures of heat exchanger tube failure analysis are designed. The stainless steel tubebundle heat exchanger and carbon steel tube bundle heat exchanger failure instances areanalyzed in accordance with this idea.Failure analysis of stainless steel tube bundle heat exchanger, applies the disintegrationand inspection analysis, microstructure analysis,and the ingredient spectrum analysis. Theanalysis shows that the E-106stainless steel tube bundle heat exchanger tube leak corrosionfactors are derived from the medium outside the tube. detect micro-cracks from tube outerwalls confirmed that the main reason of the corrosion cracking mechanism of heat exchangertubes are the stress corrosion caused by Cl-media out of tubes in the the high stress areas neartube sheet. And recommendations on measures for the cause of failure are made.The failure analysis of carbon steel tube bundle heat exchanger is in accordance with thesediment of tube body outer wall detection analysis, the tube body outer wall corrosiondetection analysis, the tube material microstructure detection analysis and the pipe inner wallstate detection analysis. The analysis shows that there are three types of the E1117A andE1117B carbon steel tube bundle heat exchanger corrosion, one is the uniform corrosion ofthe tube outer wall; two kinds are pitting and scaling corrosion of tube inner wall. Pittingcorrosion of tube inner wall causes the leakage of the tube. Heat exchanger leakage mainlydue to the tube inner wall coating quality problems causing the pitting corrosion perforationof tube inner wall. And recommendations on measures for the cause of failure are made.There is a certain engineering value in guiding heat exchanger tubes failure analysis and preventing the accident caused by corrosion in the actual production.