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

这个小型企业创新研究第一阶段项目的更广泛的影响/商业潜力是通过为集中式太阳能发电厂开发具有成本效益的高温熔盐热传递液，这将使太阳能成为一种经济和可行的可再生能源，供大众消费。随着世界范围内对能源的需求日益增长，替代能源在过去几十年里一直是研究的主要重点。用于聚光太阳能发电厂的熔盐换热流体就是此类研究的一个子领域。熔盐在高温(650摄氏度)下具有极好的稳定性，可以开采并以合理的成本轻松地制造成太阳能热传递液。此外，开发的熔盐导热流体将提高太阳能发电厂的发电效率，并通过利用普遍存在的经济金属(如不锈钢)提供潜在的成本节约。这种传热液可能会使公用事业规模的无补贴安装系统价格达到每千瓦时5-6美分的竞争性价格。该第一阶段研究项目的技术目标是(I)对316L不锈钢在熔融氯盐组成中的界面腐蚀有基本的了解，(Ii)通过使用适当的添加剂来抑制这种腐蚀。众所周知，氯盐可能会提高太阳能发电厂的运行温度(至900摄氏度)，从而提高太阳能发电厂的能源效率。然而，熔融的氯化物对太阳能发电厂使用的不锈钢管道具有极强的腐蚀性，阻碍了它们的实际应用。通过这个研究项目获得的基本腐蚀洞察力，戴纳林公司打算开发专有的缓蚀剂组合物，这些组合物可以在太阳能发电厂运行期间就地添加到氯盐中。这些添加剂在工作温度下在不锈钢表面形成连续的惰性陶瓷层，同时强化晶界，从而最大限度地减少腐蚀。Dyalene在不锈钢表面生长了几微米厚的惰性连续陶瓷层，取得了一些初步的成功。在这个项目中，Dyalene将开发一种腐蚀组件，该组件将减少钢中的脱铬，并将316L不锈钢的腐蚀速度限制在10微米/年

The broader impact/commercial potential of this Small Business Innovation Research Phase I project is through the development of cost effective, high temperature molten salt heat transfer fluids for concentrated solar power plants that would make solar power an economical and viable source of renewable energy for mass consumption. With the worldwide growing need for energy, alternative sources of energy have been the primary focus of research over the past few decades. Molten salt heat transfer fluid used in concentrated solar power plants are one sub-area of such research. Molten salts have excellent stability at high temperature (650C) and can be mined and easily manufactured into solar heat transfer fluids at a reasonable cost. Additionally, the developed molten salt heat transfer fluid would increase the efficiency of energy generation in solar power plants and provide potential cost savings by utilizing ubiquitous economical metals such as stainless steel. The heat transfer fluid could potentially bring the subsidy-free installed system price at the utility scale to a competitive price of 5-6 cents per kilowatt-hour.The technical objectives in this Phase I research project are to (i) develop a fundamental understanding of interfacial corrosion of 316L stainless steel in molten chloride salt compositions and (ii) inhibit this corrosion by utilizing suitable additives. It is known that chloride salts could potentially increase the operating temperatures (to 900 Celcius) and hence enhance the energy efficiency of solar power plants. However, the extreme corrosive behavior of molten chlorides towards the stainless steel pipes utilized in solar plants has prevented their usage for practical applications. With the fundamental corrosion insight gained through this research project, Dynalene intends to develop proprietary inhibitor compositions that can be added to the chloride salt in-situ during the operation of a solar power plant. These additives would minimize corrosion by forming a continuous and inert ceramic layer at the operating temperature on the stainless steel surface, and simultaneo usly strengthen the grain boundaries. Dynalene had some initial success in growing a few micron-thick inert, continuous ceramic layer on a stainless steel surface. In this project, Dynalene will develop a corrosion package that would reduce dechromatization in steel and restrict the corrosion rate of 316L stainless steel to 10 micro-meters/year