DYNAMIC MODEL OF A 10 MW SUPERCRITICAL CO2 RECOMPRESSION BRAYTON CYCLE

In this work, the National Energy Technology Laboratory (NETL) in collaboration with the Theiniochemical Power Group (TPG) of the University of Genoa have developed a dynamic model of a 10 MW closed-loop supercritical CO2 (sCO(2)) recompression Brayton cycle plant in the MATLAB-Simulink environment. The sCO(2) cycle modeled here is a closed cycle with an external thermal source used to heat the sCO(2) working fluid before it is expanded in a turbine. The turbine exhaust heat is recuperated using high- and low-temperature recuperators, with mixing of two compressor outlets between the recuperators (on the cold-side). About two thirds of the low-pressure sCO(2) is compressed by a main compressor, after passing through a cooler, while the remaining working fluid flows directly through a bypass compressor. The reference fluid properties (REFPROP) method by the National Institute of Standards and Technology is used to provide the thermodynamic and transport properties for sCO(2) over the cycle temperature and pressure range because the sCO(2) behavior is highly non-ideal, especially at the inlet of the two compressors. Dynamic simulations have been carried out to assess the behavior of the plant during a typical process disturbance.