Effect of coal ash on the performance of alloys in simulated oxy-fuel environments
Effect of coal ash on the performance of alloys in simulated oxy-fuel environments
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DOI：
10.1016/j.fuel.2013.09.021
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发表时间：
2014-01
期刊：
影响因子：
7.4
通讯作者：
Z. Zeng;K. Natesan;Z. Cai;D. Rink
中科院分区：
文献类型：
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作者：
Z. Zeng;K. Natesan;Z. Cai;D. Rink
富氧燃烧可以提高效率，减少燃煤电厂的污染。为了研究氧燃料环境中的材料性能，将铁基和镍基合金在750 °C下长期暴露于模拟氧燃料环境中长达6300 h。研究了灰和气体成分（SO2、CO2、H2O和O2）对合金性能的影响。这些测试的结果用于说明CO2、蒸汽和灰分在合金长期腐蚀性能中的作用。详细的结果上的重量变化，鳞片厚度，内部渗透，腐蚀产物的微观结构特征，和开裂的鳞片合金。利用同步辐射纳米束X射线衍射仪对氧化膜进行了研究，观察到灰蚀的孕育期和扩展期。在孵育时间之前，合金增加重量。在孵化时间之后，局部腐蚀破坏保护膜，合金失去重量并且腐蚀速率显著增加。由于孕育时间可以超过4000小时，长期的测试结果是更有帮助的评估在含灰的氧燃料燃烧环境中的合金性能比短期测试的结果。并对灰蚀机理进行了探讨。
Oxy-fuel combustion can increase efficiency and reduce pollution from coal power plants. To study material performance in an oxy-fuel environment, both Fe- and Ni-based alloys were exposed to simulated oxy-fuel environments at 750 °C for long terms up to 6300 h. The effects of ash and gas compositions (SO2, CO2, H2O and O2) on the performance of alloys were studied. Results from these tests are used to address the role of CO2, steam, and ash in the long-term corrosion performance of alloys. Detailed results are presented on weight change, scale thickness, internal penetration, microstructural characteristics of corrosion products, and cracking of scales for the alloys. Oxide scales were studied by synchrotron nano-beam X-ray diffraction.An incubation period and a propagation period were observed for ash corrosion. Before incubation time, alloys gain weight. After incubation time, localized corrosion damages the protective scales, alloys lose weight and corrosion rates dramatically increase. Since the incubation time can be over 4000 h, long-term test results are more helpful in evaluating the alloy performance in an oxy-fuel combustion environment with ash than the results from a short-term test. The mechanism of ash corrosion is also discussed.