炼油环境下高温腐蚀钝化膜的生长、结构与钝化机理研究

It is a challenging task for refinery to mitigate high temperature sulfidation corrosion (SC) and naphthenic acid corrosion (NAC) for crude refining equipment processing low-quality crude oil. This project focuses on the passive film formed by sulfidation corrosion. Surface analysis techniques, such as GIXRD, TEM, are used to characterize the phase structure and composition of the passive film. The passivity mechanism is investigated through the comparative analysis of compositions and corrosion resistance of the passive film. The growth mechanism of the passive film for carbon steel is investigated in a sulfur-containing medium. By examining the state of presence of the main metal elements, such as Si, Cr, Mo, Ni, Ti in the passive film, anti-corrosion property of corresponding metal sulfides and oxides is analyzed. Chemical composition of crude oil fractions is analyzed, as well as the passive film composition formed in these fractions. Therefore, the influence of crude oil fractions ingredients on the anti-corrosion property and composition of passive film can be deduced. A novel test protocol is developed to investigate the mechanism of passivity. Firstly, coupons are pre-treated in a high temperature sulfur-containing medium to form film through film-forming sulfidation corrosion. Then, coupons with passive films are challenged in an acidic medium through film-dissolving naphthenic acid corrosion. The passive films are then examined to understand the influence of alloy elements and medium compositions on the structure composition of the passive film.The research result of the project is expected to better understand the nature of passivity, to develop a new approach for passive film study, to help the development of new anti-corrosion methods, and to enhance intrinsical safety of equipment processing low-grade oil.

本项目以劣质原油加工过程中材料的高温硫腐蚀和环烷酸腐蚀为应用背景，以腐蚀钝化膜为核心研究对象，利用GIXRD、TEM等表面分析技术，测量钝化膜相结构和组成，对比分析钝化膜组成和耐蚀性，研究钝化膜耐蚀机制。研究碳钢在含硫介质中的高温硫腐蚀钝化膜的生长机制；通过考察Si、Cr、Mo、Ni、Ti等主要金属元素在钝化膜中的存在状态，研究金属硫化物、氧化物的耐蚀性能；结合对原油馏分化学成分分析和钝化膜组成分析，研究原油馏分成分对钝化膜结构、组成的影响机制，描述馏分成分对钝化膜的修饰作用，阐明馏分成分对钝化膜耐蚀性能的影响机理；采用预先硫腐蚀成膜，再环烷酸腐蚀的“挑战”（challenge）实验方法，探究合金元素、介质成分等对钝化膜结构和组成的影响，揭示钝化膜的耐蚀机理。项目预期研究成果对发展新的钝化膜研究思路、提升钝化现象的本质认识、开发新的材料防腐方法、提高装置本质安全有重要意义。

本项目以劣质原油加工过程中材料的高温硫腐蚀和环烷酸腐蚀为应用背景，以腐蚀钝化膜为核心研究对象，利用GIXRD、TEM等表面分析技术，测量钝化膜相结构和组成，对比分析钝化膜组成和耐蚀性，研究钝化膜耐蚀机制。研究碳钢在含硫介质中的高温硫腐蚀钝化膜的生长机制；通过考察Si、Cr、Mo、Ni、Ti等主要金属元素在钝化膜中的存在状态，研究金属硫化物、氧化物的耐蚀性能；结合对原油馏分化学成分分析和钝化膜组成分析，研究原油馏分成分对钝化膜结构、组成的影响机制，描述馏分成分对钝化膜的修饰作用，阐明馏分成分对钝化膜耐蚀性能的影响机理；采用预先硫腐蚀成膜，再环烷酸腐蚀的“挑战”（challenge）实验方法，探究合金元素、介质成分等对钝化膜结构和组成的影响，揭示钝化膜的耐蚀机理。项目预期研究成果对发展新的钝化膜研究思路、提升钝化现象的本质认识、开发新的材料防腐方法、提高装置本质安全有重要意义。