糠醛装置加热炉炉管腐蚀失效分析及措施

介绍了中国石油化工股份有限公司荆门分公司轻、重两套糠醛精制装置炉管的腐蚀失效问题。、通过抽出液加热炉炉管的运行状况、工艺条件、腐蚀形貌及腐蚀产物的分析发现：辐射室炉管及弯头的腐蚀泄漏主要是以糠酸腐蚀为主，由糠酸和环烷酸共同作用引起；由于炉管内介质流速和流态的影响，炉管弯头部位的腐蚀比炉管直管段严重。认为降低循环糠醛中的糠酸含量是防护加热炉炉管腐蚀的关键，并采取了一系列防腐措施：将炉管及弯头材质升级为304不锈钢；控制加热炉出口温度在（210±5）℃；新增一套溶剂回收系统；对储罐实施氮气密封保护等实施以上措施后糠醛精制装置又运行了2a。轻、重两套抽出液加热炉炉管没有发生一次腐蚀泄露情况，取得了良好的防腐效果。

Analysis of Corrosion Failure of Furnace Tubes in Furfural Unit and Countermeasures

The causes of corrosion failure of furnace tubes in two light and heavy furfural refining units were studied. The analysis of operation, process conditions, corrosion forms and corrosion products of the extract liquid furnace tubes found that the failure was caused by the combination effect of furoie acid corrosion and naphthenic acid corrosion, and the corrosion in the tulles and elbows in radiant chamber was mainly fllroic acid corrosion. Under tile impact of fluid velocity and flow state, the corrnsion in elbow of tube was more serious than that in the straigbt pipe. The reduction of furoic acid in recycle furfural is ve~ critical for the prevention of corrosion of fnrnace tubes. A number of corrosion protection measures have been adopted such as upgrading material of furnace tubes and elbows to stainless steel, eontrolling the outlet temperature of furnace at 210±5℃, adding a solvent recovery system and nitrogen blanketing of the tank, etc. After taking above measures, the furfural refining unit has been operating for two years without corrosion leaking of extract liquid furnace tubes, and good corrosion protection results have been achieved.