PITA FY2014 Projects

Understanding High Temperature Corrosion and Metal Compatibility of Molten Salt Heat Transfer Fluids for Concentrated Solar Power Applications

PI:Martin Harmer, Materials Science and Engineering

University:Lehigh University

Co-PI(s):Animesh Kundu, Materials Science and Engineering

Industry Affiliate(s):Dynalene

Summary:In this exploratory effort, we will perform a systematic investigation of the compatibility of various formulations of chloride salts (both binary and ternary eutectic mixtures producing the low freeze points) with various stainless steel and nickel alloys in collaboration with Dynalene Inc., an industry leader in the field of heat transfer fluids. These salts are promising candidates as high temperature heat transfer fluids in concentrating solar power plants (CSP). The efficiency of the CSP can be increased by the utilization of these salts because of their higher operating temperatures. Furthermore, the salts will provide an estimated 300 percent cost benefit as compared to current generation heat transfer fluids because of lower cost of production. The corrosive nature of these salts towards the metal pipes that contain it in applications has proven to be one of the principal impediments for the commercialization. The primary objectives of this project are twofold. Firstly we would identify suitable candidates for compatible salt formulation and alloy combinations by performing screening experiments. The second objective is to gain insight into the corrosion mechanism in these alloys by systematic evaluation of the effect corrosive salts on the microstructure and interfaces of various alloys at elevated temperatures with the aid of advanced analytical electron microscopy characterization tools. We envision that this scientific insight will not only provide guidelines for tuning chloride salt formulations to minimize corrosion of the alloys but will also lead to strategies for enhancing the corrosion resistance of the alloys by engineering the interfaces in those materials.