Brayton or Brayton-Rankine Combined Cycle With Hot-Gas Recirculation and Inverse Mixing Ejector

Abstract

An open/closed gas-turbine simple Brayton cycle or Brayton-Rankine gas- and steam-turbine combined-cycle power-producing system is proposed, with the gas turbine recirculating a large portion of partly expanded high-temperature gas into an inverse mixing ejector. The inverse mixing ejector uses injected-gas velocity that is necessarily greater than jet-gas velocity to increase the hot-gas pressure up to the compressor-discharge level. This is a necessary condition for achieving very high cycle thermal efficiency. Maximum combined-cycle thermal efficiency can be expected to reach up to about 80%, up to an appropriate temperature-level Carnot-cycle efficiency. The inverse mixing ejector can operate in either subsonic or supersonic (necessary for higher cycle thermal efficiencies) regions of gas velocity. The gas turbine cycle can operate in either simple-cycle, single-intercooled-cycle or multi-intercooled-cycle mode.

A gas ejector for CO2 supercritical cycles

“…Consequently, two ejector designs were proposed to fulfil the ejector requirements defined in the paper of Padilla et al [12]. The mentioned authors adopted idea of introducing the ejector into the system from the study presented in [30]. They also suggested that the investigated ejector equipped cycle can be integrated with Concentrated Solar Thermal system.…”