A High Performance Dry Gas Seal for High Temperature and Pressure Supercritical CO2 Power Cycles

As new commercial applications arise for supercritical carbon dioxide (sCO2) power generation, and higher efficiencies are achieved through higher turbine inlet pressures and temperatures, the need to advance technologies on the component level becomes essential. Power cycles using sCO2 as the working fluid are gaining increasing interest as reductions in CO2 emissions from power plants are sought and alternate energy sources are investigated. To increase efficiency, and ultimately to make them economically viable, these systems require very high turbine inlet temperatures and pressures, posing an interesting challenge to rotor system sealing. This grant application seeks to develop a high-performance dry gas seal to meet the sCO2 environment outlined in this solicitation. The proposed concept combines the best features of current dry gas seal technology with specific design enhancements and material combinations that will provide effective sealing and long service life under these extreme conditions. To achieve the project objective, MSI will combine best-in-class technologies in non-contacting, upstream-pumping seals, non-contacting bushing-type seals, and the latest in high temperature materials and coatings to produce a high performance dry gas seal design suitable for low maintenance long-term operation in advanced sCO2 power cycles.In Phase I, MSI will design its unique innovative seal and use its extensive library of computer codes, and seal system experience to create a comprehensive, realistic, multi-physics model of the seal design and its environment. The seal component parts will be individually evaluated to optimize the designs and materials, and then combined together in a high- fidelity computer model that will predict the performance of the entire assembly as a system. Interfacial materials and coatings will be selected for optimum service and start-stop wear resistance. Commercial Application and Other Benefits: MSI’s proposed effort supports both commercial and federal interests. High performance (high temperature, high pressure, high surface speed) seals can be an enabling technology in that they allow effective operation of machines that otherwise would leak internally or externally too much to be practical in sCO2 applications. MSI anticipates applications in both sCO2 and other high pressure and temperature critical shaft sealing situations ranging from turbines and process gas compressors and generator hydrogen (H2) seals in electric power generators. Advancing sCO2 power cycle machinery will allow them to become more efficient and ultimately more economical, thereby increasing their potential to penetrate the marketplace.