A Spectroscopy-Based, Real-Time, Fluid Composition Monitoring System for sCO2-Based Power Cycles

Power cycles based on a supercritical carbon dioxide (sCO2) working fluid have the potential for higher thermal efficiencies and a lower capital cost when compared to state- of-the-art, steam-based power cycles. Direct-fired, sCO2-based power cycles/systems will require fine- tuned control of the combustion process. Upsets to the operating point, which may be caused by fluctuations in the fuel composition and recycled exhaust components, could result in reduced efficiency, high pollutant emissions, or even system damage. Real-time knowledge of exhaust stream composition, notably water and carbon monoxide mass fractions, will be key to overall system operation. In the near term, sCO2-based power cycles/systems technology development would benefit greatly from the capability for real-time fuel mix and exhaust composition monitoring. What is needed is development of real-time, low-cost, rugged, fuel mix and exhaust chemical composition sensing system (for both major and minor species) for sCO2-based power cycles/systems to enable technology development and combustion process control. Sporian Microsystems has previously developed compact gas/fluid monitoring systems for the U.S. Navy and DOE based on Raman spectroscopy using cavity- based enhancement strategies that are capable of simultaneous, real-time detection of principle components (including fuel gasses) and low-level contamination. While capable of meeting many of the performance requirements in sCO2 fuel mix and exhaust composition monitoring, efforts are needed to translate/package the technology into an application-specific, industry-suitable format. Thus, the long- term objective of the proposed effort is to leverage Sporian’s prior work to realize an inexpensive, reliable, real-time composition monitoring system for sCO2-based power cycles/systems development and operation. Sporian will team with Southwest Research Institute (SwRI) for the propose effort. The Phase I effort will focus on: 1) working with technical partners and industry stakeholders to define system requirements; 2) evaluating and defining revised hardware/electronics architectures and designs; and 3) proof-of-principle testing/demonstration using benchtop-scale prototypes of enhanced-Raman-based hardware. The proposed monitoring suite will provide real-time composition information, enabling supercritical carbon dioxide technologies to provide cleaner, less expensive energy while reducing water and land usage. Better techniques for real-time composition monitoring will provide consumers with more sustainable energy sources, conserve resources, and facilitate safer and more affordable power to the consumers. Similar benefits will be seen in industries such as concentrating solar power, oil & gas, engine testing/development, power turbines, and fuel cells, among many others.