奥氏体钢在超临界CO_(2)发电系统中的腐蚀行为研究

CORROSION BEHAVIOR OF AUSTENITIC STEELS IN SUPERCRITICAL CO_(2) POWER GENERATION SYSTEM

以超临界二氧化碳(SCO_(2))作为工质的发电系统在太阳能热发电领域具有良好的发展前景。为探究SCO_(2)发电系统中典型材料的腐蚀行为,开展奥氏体钢316L和321样片在550℃、25 MPa SCO_(2)环境下的2000 h腐蚀实验研究。结果表明:两种奥氏体钢均发生了氧化腐蚀,且321耐腐蚀性能比316L更优异。腐蚀动力学近似符合抛物线规律。两种材料均形成双层氧化物,内侧为富铬垢和锰铬尖晶石,外侧形成富铁氧化物结节。此外,碳主要沉积于腐蚀产物表面,材料内部未发现渗碳现象。最后,建立了两种奥氏体钢的腐蚀机理模型。

The power generation system with supercritical carbon dioxide(SCO_(2))as the working medium is a prospect technology in the field of concentration solar power.To investigate the corrosion behavior of typical materials in supercritical carbon dioxide power genera-tion system,the corrosion experiment of austenitic steel samples of 316L and 321 exposed in SCO_(2) atmosphere at the temperature of 550℃and the pressure of 25 MPa for 2000 h was conducted.The experimental results show that oxidation corrosion occurred in austen-itic steel samples and 321 exhibits better corrosion resistance than 316L.The corrosion kinetics approximately follows a parabolic law.Both 321 and 316L forms a double oxide layer with chrome-rich scale and manganese chrome-spinel on the inside and iron-rich oxide nodules on the outside.In addition,carbon is mainly deposited on the surface of corrosion products while no carburizing phenomenon is found inside the material.Meanwhile,the corrosion mechanism model of austenitic steels is fabricated.