Closed circuit PRO series No 4: CC-PRO hydroelectric power generation prospects from the Red Sea brine and Dead Sea salinity gradient

Abstract

The Red Sea (RS) to Dead Sea (DS) water transfer project in Jordan under the sponsorship of the World Bank is intended to stop the sea-level decline of the DS as well as for the desalination of RS water and for hydroelectric power generation. Red Sea Brine (RSB ~7.13%) disposal to the DS (~34%) creates a salinity gradient of interest for PRO hydroelectric power generation and the prospects of such an application are explored in the present study with the most advanced existing tools including a new Closed Circuit PRO technology (CC-PRO) of near absolute energy efficiency without need of ERD and a recent PRO membrane (HTI-TFC) of the highest reported strength to withstand applied pressure up to 48.3 bar. Power generation prospects from RSB–DS using CC-PRO with HTI-TFC are assessed in the actual/ideal flux ratio (β) range 0.123–0.400 and High Salinity Feed (DS as draw solution) to permeation flow ratio (δ) range 1–25. The minimum β = 0.123 for said process is established from available PRO experimental data with HTI-TFC for 0.6–3.0M NaCl salinity gradients accounting for the presence of considerable concentrations of divalent cations such as Ca and Mg in DS water. The Net Electric Power (NEP) generation prospects from the RSB–DS Jordanian project using CC-PRO and HTI-TFC are assessed on the basis of 120 Mm3/year RSB availability for mixing with DS water. The results of this study accounting for the pressure limitation of HTI-TFC reveal NEP generation prospects of 7,753 kW under the conditions of δ = 1.0 and β = 0.123-0.200 from the RSB–DS gradient, or a supplement of 56.6% more power on top of the conventional hydroelectric power generation facility of the project (~13,698 kW). If the HTI-TFC membrane, or alike, could be made to operate at maximum PRO pressures of 60 and 86 bar, the CC-PRO NEP availability from RSB–DS is expected to rise to 9,767 kW (71.3%) and 13,219 kW (96.5%), respectively, with added power to the project indicated in parenthesis. In simple terms, the current state of the art revealed in this study suggest the immediate availability of the CC-PRO technology with HTI-TFC membranes for economical NEP generation from the RSB–DS gradient in the context of the Jordanian project with future improvements of membranes to withstand higher applied pressures expected to improve the economic feasibility.