GTI (Gas Technology Institute) is leading several sCO2 power cycle technology development projects. Three distinct projects are highlighted in this paper: (1) The 10 MWe Supercritical Transformational Electric Power (STEP) Pilot; (2) An indirectly heated coal/biomass-based Oxy-fired Pressurized Fluidized Bed Combustor (Oxy-PFBC); and (3) A novel high pressure oxy-combustor for direct-fired sCO2 power cycles. All three projects have significant systems engineering, optimization, operations analysis, controls, and partnership/ collaboration requirements.

In the STEP Pilot Project, a team led by GTI, Southwest Research Institute (SwRI), and General Electric Global Research, along with the University of Wisconsin and Natural Resources Canada, is executing a project to design, construct, commission, and operate an integrated and reconfigurable 10 MWe sCO2 Pilot Plant Test Facility located at SwRI’s San Antonio, Texas campus. This project is a significant step toward commercialization of sCO2 cycle based power generation and will inform the performance, operability, and scale-up to commercial power plants. The pilot plant design, procurement, fabrication, and construction are ongoing. By the end of this six-year project, the operability of the sCO2 power cycle will be demonstrated and documented starting with facility commissioning as a simple recuperated cycle configuration initially operating at a 500oC turbine inlet temperature and progressing to a recompression closed Brayton cycle technology (RCBC) configuration operating at 715oC.

In the indirectly-heated Oxy-PFBC system, sCO2 is heated via a set of hermetically-sealed heat exchangers embedded in a footerbubbling bed of solid fuel (coal and/or biomass) particles that are combusted in a mixture of oxygen and recycled CO2 at about 8 bar. The resulting compact combustor lowers the capital cost, enables higher plant efficiencies and reduces CO2 capture costs.

In the sCO2 oxy-combustor project, GTI is designing a novel high-pressure oxy-combustor for direct-fired sCO2 cycles. The design concept, which is derived from rocket engine injectors, has potential to offer performance improvements over more traditional gas turbine-derived combustors.