High Temperature, Raman Spectroscopy Based, Inline, Molten Salt Composition Monitoring System for Concentrating Solar Power Systems

One of the key recommended research activities in a recent DOE development roadmap for next generation CSP plants (CSP Gen3) was to develop an in-situ molten salt composition/chemistry monitoring system. In-situ, real time, online monitoring is the first step in carefully controlling the salts’ composition which is key to achieving thermal performance and reducing corrosion kinetics and grain boundary attack. Salt chemistry stability is a key technology enabler, as system and component design is tied to accurate and reliable thermal properties. It also impacts salt-handling protocols, and operation of critical subsystems. Ideally such a system would need to be: capable of measuring a range of molten salt compositions at target operational temperatures (as high as 800oC); capable of detecting contaminants at relevant concentrations; and rugged/reliable enough for use in industrial settings. How this problem is being addressed: Sporian Microsystems has previously developed inline, real time, gas and liquid composition monitoring systems for the DOD based on Raman Spectroscopy, and has developed a range of high temperature (1000-1800oC) sensor technologies for the energy industry, and specifically for CSP HTF/TES fluid monitoring applications. The long term-objective of the proposed effort is to leverage Sporian’s prior work on Raman Spectroscopy and high temperature sensors to realize a Raman based, high temperature capable, molten salt/HTF composition/contaminant monitoring system. Done in Phase I: In Phase I Sporian: worked with DOE national labs and industry stakeholders to define key requirements and foster technology transition; developed detailed optical, hardware, electronics, and firmware architecture designs for the complete system including the spectroscopic and high temperature operable subsections; and successfully evaluated/demonstrated performance and technical feasibility using benchtop scale prototype hardware. Planned for the Phase II Project: The Phase II effort will focus on realizing multiple versions of a commercial oriented molten salt monitoring system, and include: several generations of system design and prototyping; rigorous lab scale testing; and working with academic, national lab, and commercial technical partners to evaluate the systems in the context of ongoing DOE salt research efforts, and to clarify application utility for commercialization.Commercial Applications and Other Benefits The proposed sensor has the potential to improve the efficiency, reliability, and economic viability of CSP systems. This, in turn, will help realize the full potential of CSP to provide clean, sustainable electric power and to enhance America’s energy independence. These harsh environment composition monitoring systems could have a variety of additional applications for nuclear power generation, fossil fuel power generation, concentrating solar fuels, materials processing, and transportation systems.