The Tar Processing Tower Corrosion Failure Analysis And Research

China is a country that is rich in coal, less gas, lack of oil. Oil resources becomeshortages with the increase of people’s needs. Coal tar hydrogenation can producegasoline and diesel. Therefore, processing and utilization of coal tar has importantpractical significance and strategic significance. With the development of coalchemical industry, coal tar corrosion is increasingly becoming the common problemsof troubled enterprises. Study the issue became a major mission of the researchinstitute.This project is from a tar chemical plant. Coal tar processing device is corrosionfailure in the production process. The main corrosion failure device is a distillationtower and top condenser. In this article, by the way of scene view, materials analysisand experimental simulation concluded the following. Top condenser tubes corrosioncracking is due to stress corrosion cracking. The Cl－is leaked from the heat transfertube into the heat transfer tube shell. The Cl－is accompanied by the flow of theliquid phase into the distillation. In the distillation The Cl－leads to pitting corrosionand destroys passivation film on the stainless steel surface. The tar and creosote of thedistillation contain sulfur ions and sulfide. Sulfur corrosion increased the process ofpitting corrosion. Cl－corrosion, sulfur corrosion, erosion and electrochemicalcorrosion work jointly. Pitting corrosion is connected into the surface, resulting in alarge area of the tower corrosion.In the distillation the liquid-liquid contact area is serious corrosion. Old towerneeds to cut off, then welds new tower. There are six possible welding programs. Bythe experimental methods, conduct research and comparison. By testing six kinds ofwelding materials and taking into consideration all factors, finally, select the optimumwelding program.