SEMI-EMPIRICAL MODEL FOR PREDICTING THE SPECIFIC ENERGY CONSUMPTION IN REVERSE OSMOSIS DESALINATION

The first goal of this study is to examine the performance of a semi-empirical model used for calculating specific energy consumption (SEC) in reverse osmosis desalination. We have introduced a simulation tool (SECSM) to compare this semi-empirical model (SECSEM) and the SECSM. It's worth noting that the simulation model is open source and can be easily integrated easily with other software tools. For this comparison, we explored a temperature range T (10°C - 22°C - 35°C), recovery rate R from 30% to 65%, and a pump efficiency range of γ_HPP ~78% to 98%. An increase in these parameters leads to a decrease in SEC (both SECSEM and SECSM) for systems without energy recovery devices (ERD). However, the introduction of an ERD results in a variable change in SECSEM. Under specific conditions of 35°C, a pump efficiency of 98%, and an R of 65%, the SECSEM reaches its minimum values. In the case of the two-stage unit (TS), the SECSEM and SECSM models converge to the same value of 0.28 KWh/m³. Meanwhile, for the single-stage unit (SS), the values are 0.4 KWh/m³ and 0.39 KWh/m³, respectively. Regarding the unit equipped with the BW 400 34 and SW HF 085 31 membranes, in both SS and TS configurations, the energy consumption for both models converge towards the values 0.71 KWh/m³, 0.70 KWh/m³, and 0.95 KWh/m³, 0.94 KWh/m³ respectively. In the second part of this paper, a comparative study to validate this semi-empirical model without ERD against experimental data was conducted. The SECSEM showed values very close to the experimental results. The findings are discussed below.