甲醛回收塔加碱降酸防腐蚀工艺技术改造

Transformation of Etching Process in Formaldehyde Recovery Tower

针对三聚甲醛装置中甲醛回收塔由于高温氧化产生甲酸导致设备及管道腐蚀泄漏,装置无法长周期稳定运行的问题,分析了甲酸产生机理及加碱降酸的理论依据,采取了加碱降酸工艺技术改造措施,对加碱后可能出现的问题进行了分析总结并提出了解决方案。改造结果表明,有效解决了甲醛回收塔顶底采出物料中甲酸含量偏高的问题,解决了甲醛回收塔附属设备及管道的腐蚀问题,提高了甲醛回收塔的运行周期,节约了维修成本,使整个三聚甲醛装置运行效率明显提高,效果显著。

Due to the generation of formic acid during the high-temperature oxidation process, the equipment and pipes in the Formaldehyde recovery tower are easily corroded and thus leaked, so that the whole system cannot operate stably for a long time. This paper analyzes the principle of formic acid generation as well as the theoretical basis of adding alkali to reduce acid and suggests a transformation plan on such basis. The possible problems after adding alkali has been analyzed and related solutions are discussed. The transformation result indicates that, the adding of alkali effectively reduces the formic acid content and the problem of accessory equipment/pipeline corrosion is solved. The formaldehyde recovery tower can thus enjoy a longer operation cycle and the maintenance cost is largely saved.