Design of a Binary Cycle Plant for an Operating Flash Plant at Olkaria V Power Station in Kenya

The objective of this study is to design a heat recovery system to generate extra electricity from used brine leaving the flash tanks of a single flash Olkaria V geothermal power plant to convert the power plant from single to a combined flash-binary cycle plant with higher efficiency and power output. In this study, a binary cycle power plant is designed for an operating single flash plant at Olkaria in Kenya to extract waste heat from used brine leaving the flash tank. The design typically involved integrating an Organic Rankine Cycle (ORC) for recovery of waste heat from the residual high-temperature brine that would otherwise be reinjected. The options considered showed potential to increase the generation capacity of the plant by 13–28% and improve system efficiency. The study investigated the performance of geothermal flash and binary power plants and proposes an optimized hybrid system integrating a binary cycle into existing flash plants. The study showed that using the R245fa as the sevondary working fluid, the Organic Rankine cycle can produce 9.5 MW extra power.