(601e) Dynamic Process Modeling for a 10 MWe Supercritical CO2 Recompression Brayton Pilot Plant Design

Supercritical carbon dioxide (sCO2) Brayton power cycles offer significant benefits over conventional steam Rankine cycle power plants. Closed, indirect Brayton power cycles use an external thermal source (e.g., solar, nuclear or fossil) to heat compressed working fluid which is expanded in a turbine, generating electricity and exhaust heat for recuperation. Using sCO2 as the working fluid provides the potential for thermal efficiencies over 50 percent, more compact designs, lower costs, and reduced greenhouse gas emissions. In view of these promising advantages, the U.S. Department of Energy under its Supercritical Transformational Electric Power Program is working with industry and research partners to design, build, and operate a 10 MWe (megawatts electrical) sCO2 pilot plant test facility. The new facility will support the future commercialization of sCO2 Brayton cycle energy conversion systems by testing and demonstrating the potential energy efficiency and cost benefits of this technology.

In this work, a dynamic pressure-driven process model of a closed, indirect 10 MWe recuperated sCO2 recompression Brayton cycle integrated with natural gas-fired burner has been developed in Aspen Plus Dynamics. The dynamic model can predict off-design and part-load performance and provide time-dependent profiles of key outputs such as power generated and thermal efficiency as a function of compressor inlet temperature and pressure, turbine inlet temperature, bypass recompression fraction, and other key process variables. The dynamic model, assumptions, and specifications will be described for the key components and overall cycle. The presentation will also highlight transient responses and operational strategies for maximizing sCO2 cycle efficiency and net power during typical pilot plant disturbances and off-design testing.