Single and multi-objective optimization of sweeping gas membrane distillation with double-stage bubble column dehumidifier

This paper investigates the integration of the Sweeping Gas Membrane Distillation (SGMD) module with two stages of the Bubble Column Dehumidifier (BCD). The initial stage of the BCD incorporates environmental water at ambient temperature for dehumidification purposes, whereas the subsequent stage employs chilled water. A comparative analysis is conducted between the proposed system and a conventional setup, incorporating an SGMD unit integrated with only one BCD stage cooled with chilled water. The evaluation includes productivity, Gained Output Ratio (GOR), and Specific Energy Consumption (SEC). A single-objective optimization approach using the Differential Evolution (DE) algorithm is utilized to determine the optimal operational and design parameters for the proposed system. Additionally, the multi-objective Nondominated Sorting Genetic Algorithm (NSGA∥) optimization technique is employed to ascertain the optimal SEC and flux for each system. Furthermore, a cost analysis is carried out and compared not only between the two systems but also with other Membrane Distillation (MD) techniques. The findings reveal that the proposed system achieves a 12.08 % higher productivity compared to the conventional system. Moreover, for a productivity level of 100 kg/m².hr from both systems, the present system exhibits a 51.228 % lower SEC than the conventional system. Finally, the cost analysis, using the multi-objective optimization technique, demonstrates that the Unit Production Cost (UPC) of the distilled water in the proposed system is 35.26 % lower than the conventional system documented in the literature.