The equivalent combined cycle of an irreversible chemical potential transformer and its optimal performance

A chemical potential transformer operating among three reservoirs at different chemical potentials is analogous to a heat transformer operating among three heat reservoirs. When the influence of finite-rate mass transfer between the working fluid and the reservoirs is taken into account, a chemical potential transformer may be conceived as a combined system having a chemical pump driven by a chemical engine. The fundamental optimal relations of the chemical engine and pump operating between two reservoirs are used to derive the fundamental optimal relation of the chemical potential transformer. Consequently, it is proved that such a combined cycle system is equivalent to the chemical potential transformer operating among three reservoirs at different chemical potentials. Moreover, the main optimal performances of the chemical potential transformer are discussed. The results obtained here may reveal some inherent connections between the chemical potential transformer and the chemical engine and provide a theoretical base for the development of chemical potential transformers.