碳钢经表面处理代替不锈钢制造甲醛氧化反应器

不锈钢制甲醛氧化反应器(废热锅炉)使用寿命短的主要原因是由于晶间腐蚀、点腐蚀和磨损腐蚀及其综合作用对管壁的腐蚀破坏所致。用经表面处理的碳钢代替不锈钢制造甲醛氧化反应器,可改善和避免上述腐蚀破坏的产生,延长氧化反应器的使用寿命.湘潭合成化工厂,用经由我们以Mo、p元素进行表面钝化处理的20g碳钢代替1Cr18Ni9Ti不锈钢制造甲醛氧化反应锅炉,现已运行19个月,使用寿命已超过该厂原不锈钢制造的氧化反应锅炉的平均寿命;甲醛质量稳定,达到GB9009-88中的优级品标准;不仅大幅度降低了设备费用,延长了使用寿命,而且因减少泄漏等事故,使该厂去年甲醛增创产值180万元.研究表明,采用表面合金化处理的碳钢管来制造甲醛氧化反应锅炉,效果更佳,是解决甲醛氧化反应废器热锅炉腐蚀问题,延长使用寿命的有效途径和最佳选择。

A NEW SUBSTITUTION OF THE CARBON STEEL AFTER SURFACE TREATMEMT FOR STAINLESS STEEL USED IN FORMALDEHYDE OXIDATION REACTORS

The main reason leading to short service life of the formaldehyde (CH_2O)oxidation reactor ( i.e waste heat boiler) made of stainless steel is the intergranular corrgsion Pitt-ing corrosion and wear corrosion.The effects by those types of corrosion and their combi-nation cause the tube walls to be destroyed.Howevev substitution of carbon steel after sur-face treatment for the stainless steel can avoid these types of corrosion and thus increasethe service life of the reactor.20g carbon steel after passivation surface treatment by us us-ing Mo and P eet hasbecn used as the tube materials tto substitute for 1Cr18Ni9Ti stainlesssteel in the oxidation reactor in Xiangtan Synthetic and Chemical Plant, and the rebuiltreactor has been run for 19 months which is over the average service life of the previousone.The quality of formaldehyde produced from the rebuilt reactor remains stable and meets therequirements of the first-grade according to the national standard GB9009-88.This substitutionhas not only greatly decreased the costs of equipment, but also led to an increment of outputvalue of formaldehyde by 1800, 000 Yuan in 1991 due to less leakage of formaldehyde fromthe reactor caused by corrosion.The Present work also has shown that the carbon steel afteralloying surface treatment exhibits corrosion resistance, and thus predicated that its appli-cation in the oxidation reactor will increase the service life further.This can be considerdas the best alternative to solve the corrosion problem in the oxidation reactor in formal-dehyde industry.