Performance Analysis of Seawater Desalination Using Reverse Osmosis and Energy Recovery Devices in Nouadhibou

Arid zones, such as the MENA regions and the Sahara countries, are experiencing significant water stress. To address this global challenge, desalination technologies provide a crucial solution, particularly the reverse osmosis (RO) technique, which is widely used to treat Seawater or Brackish water. Mauritania is among the countries facing a scarcity of potable water resources and relies on desalination technologies to meet its water demand. In this work, a numerical and experimental study was carried out on the functional and productive parameters of the Nouadhibou desalination plant in Mauritania using MATLAB/Simulink (R2016a). The study considered two operating scenarios: with and without the energy recovery unit. The objective of this paper is to perform an analytical study of the operating procedures of the Nouadhibou RO desalination plant by varying several parameters, such as the pressure exchanger, and the feed water mixing ratio in the pressure exchanger unit, etc., in order to determine the system’s optimal operating point. This paper analyzes the system’s performance under different conditions, including recovery rate, feed water temperature, and PEX splitter ratio. In Case No. 1 (without a pressure recovery unit), and with a recovery rate of 20%, doubling the plant’s productivity from 400 to 800 m3/d requires 400 kW of power. In contrast, in Case No. 2 (with a pressure recovery unit), achieving the same productivity requires only 100 kW, with a 75% of energy saving. When the desalination plant operates at a productivity of 400 m3/d@40%, the SPC decreases from 6 kWh/m3 (Case No. 1) to 2.7 kWh/m3 (Case No. 2), resulting in a 55% specific power consumption saving. The results also indicate that power consumption increases with both feed water temperature and PEX splitter ratio, while variations in these parameters have a negligible effect on permeate salinity.