SUPERCRITICAL CO2 CYCLES FOR GAS TURBINE COMBINED CYCLE POWER PLANTS

摘要

Supercritical carbon dioxide (sCO2) used as the working fluid in closed loop power conversion cycles offers significant advantages over steam and organic fluid based Rankine cycles. Echogen Power Systems LLC has developed several variants of sCO2 cycles that are optimized for bottoming and heat recovery applications. In contrast to cycles used in previous nuclear and CSP studies, these cycles are highly effective in extracting heat from a sensible thermal source such as gas turbine exhaust or industrial process waste heat, and then converting it to power. In this study, conceptual designs of sCO2 heat recovery systems are developed for gas turbine combined cycle (GTCC) power generation over a broad range of system sizes, ranging from distributed generation (~5MW) to utility scale (> 500MW). Advanced cycle simulation tools employing non-linear multivariate constrained optimization processes are combined with system and plant cost models to generate families of designs with different cycle topologies. The recently introduced EPS100 [1], the first commercial-scale sCO2 heat recovery engine, is used to validate the results of the cost and performance models. The results of the simulation process are shown as system installed cost as a function of power, which allows objective comparisons between different cycle architectures, and to other power generation technologies. Comparable system cost and performance studies for conventional steam-based GTCC are presented on the basis of GT-Pro? simulations [2]. Over the full range of systems studied, the sCO2 cycles generated higher power output at a lower cost than the comparable steam systems. Projected operation and maintenance (O&M) costs are used to calculate projected levelized cost of electricity (LCOE) for the competing cycles, demonstrating that sCO2 systems can provide a significant LCOE advantage across the full range of sizes studied.