STTR Phase II: Corrosion Inhibition of Stainless Steel Alloys in High Temperature Chloride Salts for Concentrated Solar Power Applications

这STTR第二阶段项目将集中在开发具有成本效益的，高温熔盐传热流体的第三代集中太阳能发电（CSP）厂的工作温度700？C.在本研究的第一阶段，开发了一种添加剂包，在700 ℃下在316/316L不锈钢上形成粘附性陶瓷氧化物涂层。当加入到特定的氯化物盐混合物中时，可抑制腐蚀。缓蚀剂包策略的使用将使CSP工厂能够使用经济的不锈钢合金，并将降低基础设施成本。这些解决方案将对可再生能源市场产生直接影响，这将有助于降低热太阳能的平准化能源成本（LCOE），从目前的12？/ kwh到目标3？/到2030年的千瓦时。在该项目中获得的科学和技术见解可能有利于许多其他应用，如熔融碳酸盐燃料电池，热能储存系统，核熔融氟化物/氯化物反应堆，以及其他易受侵蚀性腐蚀的高温系统。在CSP工厂中加入抑制性熔融氯化物盐还将提供可持续的绿色能源，减少用水量，创造更多就业机会，并为美国提供能源独立和安全。在社会层面上，影响将通过继续提供和发展教育活动的基础上，研究课题体现了这项工作。在这个拟议的计划的核心创新是化学混合物的发展，一个添加剂包，将尽量减少腐蚀的不锈钢引起的熔融氯化物盐在温度700？C.添加剂包反应的不锈钢和形成腐蚀抑制陶瓷氧化物涂层原位时，添加到熔融氯化物在操作温度700？C.氯化物盐被建议作为第三代CSP装置的传热流体。在真实的世界CSP工厂的抑制剂包策略的可行性将严格评估在这项拟议的研究。将设计和建造一个原型实验室规模的熔融试验回路，以模拟CSP工厂的流动条件。将研究在动态条件下长时间暴露于高温熔融盐对基体金属的机械性能的影响，并注意熔融盐引起的高温下强度和韧性的退化。还将研究具有抑制剂包的盐的降解行为。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This STTR Phase II project will focus on the development of cost effective, high temperature molten salt heat transfer fluids for third generation concentrated solar power (CSP) plants with operating temperatures 700?C. In the Phase I of this research, an additive package was developed that formed an adherent ceramic oxide coating on 316/316L stainless steel at the temperatures 700?C when added to specific chloride salt blends and inhibit corrosion. The utilization of the inhibitor package strategy will enable the utilization of economical stainless-steel alloys in the CSP plants and would reduce the infra-structure cost. Such solutions will have a direct impact on the renewable energy market which would help to lower the Levelized Cost of Energy (LCOE) for thermal solar from the current cost of 12?/kwh to the target 3?/kwh by 2030. The scientific and technological insight gained in this project could be beneficial to many other applications, such as molten carbonate fuel cells, thermal energy storage systems, nuclear molten fluoride/chloride reactors, and other high-temperature systems that are susceptible to aggressive corrosion. Incorporation of the inhibited molten chloride salt in the CSP plants will also provide sustainable green energy, reduce water usage, create more jobs and offer U.S. energy independence and security. On a societal level, impact will be achieved by the continued delivery and development of educational activities based on the research topics embodied by this work.The core innovation in this proposed program is the development of a chemical mixture, an additive package that would minimize the corrosion of stainless steel induced by molten chloride salts at temperatures 700?C. The additive package reacts with the stainless steel and forms a corrosion inhibiting ceramic oxide coating in-situ when added to the molten chlorides at operating temperatures700?C. The chloride salts are proposed to be the heat transfer fluids for third generation CSP plants. The feasibility of the inhibitor package strategy in a real world CSP plant will be critically assessed in this proposed research. A prototype bench scale molten test loop will be designed and built to mimic the flow conditions in a CSP plant. The effect of prolonged exposure to high temperature molten salts on the mechanical properties of the base metal under dynamic conditions will be studied with attention to the molten salt induced degradation of strength and toughness at elevated temperatures. The degradation behavior of the salt with the inhibitor package will be studied as well. Additional research will be performed to gain fundamental insight on the nucleation and growth of the ceramic oxide coating and its thermal and mechanical stability in dynamic flow conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.