SHMTO工艺中蒸汽-甲醇过热器失效原因探究

ON THEFAILURE CAUSES OF STEAM-METHANOL SUPERHEATER IN SHMTO PROCESS

甲醇制烯烃(MTO)工艺是连接煤制烯烃上下游流程的瓶颈,而甲醇过热器则是MTO工艺中非常关键的换热设备。文章针对SHMTO工艺中U形管式甲醇过热器的异响及泄漏问题,从振动频谱入手对异响原因进行分析,同时从管束腐蚀的情况入手对泄漏原因进行剖析,得出如下结论:振动导致异响的原因在于换热器结构设计不合理;而泄漏的原因在于粗甲醇中杂质对碳钢的腐蚀,尤其是在温度较高的情况下。针对上述原因对该换热器进行了改造,并更换了高温换热介质。改造后的甲醇过热器已连续满负荷运行超过12个月,运行状态良好,无振动异响及泄漏。

Methanol to olefins(MTO)process is the bottleneck connecting the upstream and downstream processes of coal to olefins,and methanol superheater is a very critical heat exchange device in MTO process.Aiming at the abnormal noise and leakage of the U-shaped tube bundle methanol superheater in the SHMTO process,this paper analyzes the causes of abnormal noise from the vibration spectrum,and analyzes the causes of leakage from the corrosion of the tube bundle.It is concluded that the reasonfor theabnormal noise caused by vibration is the unreasonable design of the heat exchanger structure,and the reason for the leakage is the corrosion of carbon steel caused by impurities in the crude methanol,especially at higher temperatures.Aiming at the above reasons,the heat exchanger was revamped and the high-temperature heat exchange medium was replaced.The revamped methanol superheater has been running continuously at full load for more than 12 months,and it is operating in good condition without any abnormal noise caused by vibration or leakage.