نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Nowadays, reverse osmosis technology accounts for over 70% of global water desalination capacity. However, no well-defined criterion currently exists for selecting the number of membrane elements within pressure vessels in RO configuration design. Since this design variable directly affects system performance and associated costs, determining the optimal PV length remains a challenging task. This study investigated the effect of PV length on the techno-economic performance of brackish water reverse osmosis systems used for the reuse of pretreated wastewater with a total dissolved solids concentration equivalent to 2000 mg/L NaCl. Accordingly, two design scenarios with permeate capacities of 18 and 155 m³/h were evaluated, considering configurations containing 4 to 8 membrane elements per PV. The hydraulic and mass-transfer performance of the systems was simulated using DuPont WAVE software. The systems were assessed using seven key indicators, including hydraulic behavior, maximum recovery, permeate quality, specific energy consumption, capital expenditure, operating expenditure, and levelized cost of water. Increasing PV length enhanced the maximum achievable system recovery. In both scenarios, salt rejection exceeded 98%, while recovery was the primary factor determining permeate quality. Feed pressure and SEC exhibited nonlinear relationships with recovery and PV length. At high recovery levels, hydraulic balance and permeate backpressure had a greater influence on energy consumption than pressure drop. Accordingly, the 8-element configuration at the small scale and the 6-element configuration at the large scale provided the best compromise among feed pressure, pressure drop, and energy consumption. From an economic perspective, increasing the PV length increased CAPEX by 7% and 3.5% in the small and large-scale scenarios, respectively. Nevertheless, increasing the PV length and recovery reduced OPEX. The minimum LCOW values were 0.1309 $/m3 for the 8-element configuration at 80% recovery in the small-scale scenario and 0.1100 $/m3 for the 6-element configuration at 75% recovery in the large-scale scenario. These results indicate that in large-scale projects, selecting more balanced PV lengths, such as the 6-element configuration, provides a superior techno-economic trade-off compared to longer alternatives, whereas in small-scale systems, the 8-element configuration serves as a justifiable option to achieve the minimum water production cost.
کلیدواژهها English
