电石炉尾气制氢预热器封头泄漏失效分析

Analysis of leakage failure of preheater head for hydrogen production from calcium carbide furnace tail gas

电石在生产过程中产生的炉气中富含较多氢气,提取电石炉尾气中的氢气可以提高尾气再利用率、增加效益。在800Nm^(3)/h电石炉尾气制氢装置运行过程中,预热器装置的封头泄漏。该封头材质为奥氏体S30408不锈钢,预热器内的尾气介质含有硫化氢,蒸汽冷凝水中含有较多氯离子,制氢装置在停车置换时,内外温差过大,装置内部有水雾产生。由此可以得出封头泄漏失效原因:304不锈钢在带液态水的硫化氢和氯离子环境下会产生应力腐蚀开裂。该失效分析可为预热器封头装置的优化设计提供理论指导,以提高预热器装置的使用寿命,降低运行成本。

The furnace gas generated during the production process of calcium carbide is rich in hydrogen gas.Extracting hydrogen gas from the tail gas of the calcium carbide furnace can improve the utilization rate of tail gas and increase efficiency.During the operation of the 800Nm^(3)/h calcium carbide furnace tail gas hydrogen production unit,the head of the preheater device leaked.The material of the head is austenitic S30408 stainless steel.The exhaust gas medium inside the preheater contains hydrogen sulfide,and the steam condensate contains a lot of chloride ions.During the shutdown and replacement of the hydrogen production unit,the temperature difference between the inside and outside is too large,and water mist is generated inside the unit.From this,it can be concluded that the cause of head leakage failure is that 304 stainless steel will undergo stress corrosion cracking in an environment with hydrogen sulfide and chloride ions in liquid water.This failure analysis can provide theoretical guidance for the optimization design of the preheater head device,in order to improve the service life of the preheater device and reduce operating costs.