Corrosion Causes of Distillation and Crystallization System in Nitrochlorobenzene Plant and Countermeasures

Corrosion problems often lead to unplanned shutdown of nitrochlorobenzene plants, especially in distillation and crystallization systems, which seriously affect the safe and stable operation of the plant for a long period. Based on the analysis of process materials in field, the sources of corrosive media in distillation and crystallization system were identified by hydrolysis and pyrolysis tests. The corrosion rules of process side and circulating water side of crystallizer and the corrosion rules of liquid ring vacuum pump were studied through corrosion simulation tests in laboratory and corrosion coupon tests in field. At the same time, the corresponding anti-corrosion measures were proposed to solve the long-term corrosion problem of nitrochlorobenzene plant.