压力容器器壁中的氢浓度分布的计算

氢进入金属材料中会引起金属材料的内部损伤。氢进入大型锻件中引发发裂（Shatter Cracks）；氢进入钛金属材料中使钛材氢化，可能引起火灾；在加工含硫原油的工艺过程中，湿硫化氢腐蚀过程中产生的氢原子进入钢材中，会引发硫化物应力腐蚀开裂（SSCC），氢致开裂（HIC）和硫化物诱导氢致开裂（SOHIC）等内部损伤；在高温和高压临氢环境中，氢分子裂解为氢原子进入钢材中会引发氢侵蚀（HA）等多种类型的内部损伤。氢损伤主要是金属材料硬化、脆化和内部损伤，是氢进入金属材料中降低了金属的流变性。压力容器安全的关注点是氢如何进入金属材料中且其分布状态如何。根据菲克第一定律，建立了求取关键参数的方程（6）。借助试差法求得不同器壁厚度情况下的真实值，计算出所需的氢浓度及器壁中的氢浓度分布状态。最后简单地评价了膏屡拍作用．

Hydrogen Concentration Calculation in Pressure Vessel Wall

Hydrogen will result in internal damage （hydrogen damage） when it enters steel materials. For example：It will result in shatter cracks when it enters large forgings and lead to hydriding in Titanium or even fire when it enters Ti steels. In processing sulfur crude oil, the wet hydrogen sulfide corrosion environment will cause SSCC, HIC, SOHIC. In high - temperature and high - pressure hydrogen services, hydrogen molecules split into hydrogen atoms and enter steels, causing internal damages like hydrogen brittling, etc. Hydrogen damages mainly are steel hardening brittling and internal damage because the hydrogen in the steel material has reduced the metal rheology. Therefore, safety of pressure vessels shall focus on how the hydrogen enters the steel material and what is its distribution. The pi equation （6） is established based upon Fiek＇s First Law to work out critical parameter pi which is the hydrogen pressure between overlay layer and base metal. By trial and error method, the actual pi value is determined and the required hydrogen concentration and concentration distribution in shell wall are calculated. The effect of overlay layer is finally evaluated.