Development of Super Environment-Resistant Steels for High-Temperature and High-Efficiency Waste-to Power Plant Schemed for the Minimized Environmental Risks

今天，废物处理技术正处于转折点，既要实现更合理的社会资源循环体系，又要通过提高废物发电效率等方式实现更复杂的能源利用和/或回收。为了促进低成本、高耐蚀的钢基过热器管材的商业化引进，高温锅炉过热器采用高耐蚀合金材料作为高温锅炉过热器的材料是非常必要的，因为这种环境具有很强的侵蚀性，对过热器管子表面的熔盐沉积和含有高浓度腐蚀性氯化物的废气都会造成非常严重的高温腐蚀破坏。本研究在腐蚀失效分析和合金设计的基础上，利用最新研制的高温腐蚀试验装置--“变温高温腐蚀试验装置”，可以精确地控制周围气体气氛与钢材之间的温度梯度和/或温度差。在此基础上，主要通过多元回归分析，阐明了主要合金元素对耐蚀性的影响，并从有效开发氧化物保护层的角度，提出了改善腐蚀性能的合金设计思想。并指出了近期需要解决的技术问题。

Waste treatment technology is crossing today at the turning point for attaining both much more reasonable society system of resource cycling and more sophisticated energy utilization and/or recovery through such as improving an efficiency of waste-to-power generation. It is strongly required for such a waste power plant system innovation to introduce commercially the highly corrosion-resistant alloy materials as a superheater for high-temperature boiler, since such an environment is highly aggressive to cause very sever high-temperature corrosive damage associated with both the molten salt deposited onto the superheater tube surface and flue gas containing high concentration of also aggressive chloride compounds.In the present research work has been made in order to promote the commercial introduction the low cost and highly corrosion-resistant superheater tube materials based on the steel, on the bases of the corrosive failure analysis and alloy design, by using the newly developed high-temperature corrosion testing apparatus termed as "temperature variable high-temperature corrosion testing apparatus" which enable to control intensively the temperature gradient and/or difference between surround gas atmosphere and steel metal.On the basis of the results obtained, the effect of principal alloying element on the corrosion resistance was clarified mainly by means of he multiple regression analysis, and an alloy design concept was established for improving the corrosion performance particularly from the viewpoint of developing effectively the protective oxide scale layers. Furthermore, the technological subjects to be solved in near future were also pointed out.