柴油加氢装置铵盐结晶腐蚀及防护措施

Corrosion and Protective Measures of Ammonium Salt Crystallization in Diesel Hydrogenation Unit

柴油加氢装置操作工况苛刻,而且随着原料性质、加工负荷、设备运行等条件的变化,偏离设计的操作工况。高压系统反应产物-低分油换热器管程介质操作温度逐渐降低,反应产物中的氯化铵结晶点前移,易在换热器管束中沉积,使高压系统压力降持续增大,同时结晶铵盐的垢下腐蚀导致管束内漏,严重影响装置的安全运行。分析了铵盐结晶原因和计算了换热器氯化铵析出温度点,从生产运行的角度提出并实施防腐蚀措施,有效地遏制了高压系统压力降增大,延长了换热器管束使用寿命。

The heat exchanger for reaction product/LP separator oil in a diesel hydrogenation unit was operated under harsh conditions.With the changes of raw material properties,processing load and equipment operation efficiency,actual working condition of the heat exchanger deviated from the designed operating condition.As the operating temperature of the medium along the tube side decreased gradually,crystallization point of ammonium chloride declined.Salt precipitated and deposited in the tube bundle of heat exchanger,which made the pressure drop of high-pressure system continuously increased.Meanwhile,the under-deposit corrosion caused by ammonium salt crystallization led to the leakage of tube bundle,which seriously affected safe operation of the unit.By analyzing the reason as well as calculating the crystallization point of ammonium chloride in the heat exchanger,anti-corrosion measures were put forward and applied,which effectively restrained the increase of pressure drop in high-pressure system,and extended service life of the heat exchanger.