Warm gas carbon dioxide capture from the anode off-gas in solid oxide fuel cell-gas turbine hybrid power generation systems: A technoeconomic investigation considering economies-of-scale

• Warm-gas CO 2 capture with cost-of-capture of $74.87 (with TS&M) or $46.18 (without TS&M) per metric tonne of CO 2 • Economies-of-scale of carbon capture in SOFC-GT hybrid systems • Economies-of-scale of SOFC-GT hybrid systems • Labor costs and capital expenditure are the main driving factors for economies-of-scale The thermodynamic and economic performance of a warm gas pressure swing adsorption (PSA) technology for CO2 capture directly from the anode off-gas in a solid oxide fuel cell (SOFC)-gas turbine (GT) hybrid power generation system is investigated. Warm gas CO 2 capture provides advantages over ambient temperature CO 2 capture by retaining water vapor in the anode off-gas, simplifying heat integration and preserving higher mass flows through the turbine, maximizing energy efficiency and downstream power generation. Four cases of a natural gas (NG)-powered SOFC-GT hybrid plants are compared: 10 MW and 50 MW systems without carbon capture, and 50 MW and 100 MW systems with carbon capture. At the 50 MW scale, the efficiency of the system without carbon capture achieves 75.32%-LHV and the system with carbon capture achieves 68.22%-LHV. This decrease in efficiency is governed by the loss of mass that moves through the turbine and the energy penalty associated with the heat needed for regeneration. The cost-of-capture of the warm gas PSA system is $74.87 (with TS&M) or $46.18 (without TS&M) per metric tonne of CO2. Efficiency improvements due to scaleup are marginal, nevertheless, the larger-scale hybrids are shown to be substantially more cost-effective. Comparing the 50 MW hybrid with carbon capture to the 100 MW hybrid, the specific plant cost decreases by 4.7% and the cost of electricity decreases by 5.4%. The analysis establishes warm gas PSA as a promising approach for integrating efficient and economic carbon capture into SOFC-GT hybrid power generation systems.