Dynamic Optimization of Multieffect Seawater Distillation to Gain Insights into Various Feeding Patterns: Productivity, Thermodynamic, Economic, and Environmental Perspectives

Abstract

Seawater desalination is consistently gaining research interest, as water scarcity looms globally. Multieffect distillation with thermal vapor compression (MED-TVC) has emerged as a promising solution to the freshwater scarcity problem. In this contribution, we put forward a way to gain physical insights into various feeding patterns of MED-TVC and identify a suitable pattern to treat saline water effectively. For this, a dynamic model for a MED-TVC with parallel cross feed (PCF) is first formulated and then validated it with data sets of two different plants showing excellent matching. This validated model is further extended for dynamic multiobjective genetic algorithm-based optimization by framing four conflicting objectives in the aspects of performance ratio (PR), second law efficiency (η II ), freshwater production cost (FWPC), and CO 2 emission. With this, we formulate the technique for order of preference by similarity to ideal solution (TOPSIS) embedded nondominated sorting genetic algorithm-II (NSGA-II). A systematic comparison is presented between the optimal performance of the three feeding patterns, namely, forward, parallel, and parallel cross feed MED-TVC operating under optimal configurations. The relative merits and demerits of each feeding pattern are discussed, and among them, the PCF comes out as the front-runner with minimum cost (FWPC) and emission level and maximum performance ratio and thermodynamic efficiency. This study provides a clear and optimal picture based on the stated objectives and properly guides to choose a suitable feeding methodology for seawater desalination in MED-TVC.

Solar-Driven Thermal and Mechanical Vapor Compressor Integrated Desalination System: Zero Emission, High Yield, and Cost Reduction

“…As shown in Table , a very close resemblance to the plant data is obtained for the MED-TVC with a REP value of 2.3% in terms of the gain output ratio (GOR), whereas it is 2.55% for the reported model. It should be noted that this model is validated elsewhere with an additional set of plant data, whereas here we compare the MED formulation with an existing model along with a plant data set.…”

“…Further, MED is designed with different feeding patterns, namely forward feed (FF), backward feed (BF), parallel feed (PF), and parallel cross feed (PCF). Among them, PCF has shown better performance − even under optimal operating conditions . Hence, the PCF feeding arrangement is adopted here for further advancement.…”

“…This innovative desalination scheme is integrated with two vapor compression cycles, namely TVC and MVC, to acquire both of their benefits along with unlocking the thermodynamic limitation. To meet these objectives, at first we validate the developed MED-TVC model with plant data . The MVC is proposed to integrate with MED-TVC, and the resulting hybrid MED-TVC-MVC scheme is subsequently evaluated over the MED-TVC in terms of productivity and freshwater production cost (FWPC).…”

A Carbon-Neutral Highly Productive Solar-Powered Desalination Process: Improving Economic Performance with Carbon Pricing

“…Unlike BF, the PCF does not require a pump between each pair of effects starting from the last effect along with a thick-liquor pump. According to a recent study, under optimal conditions, PCF has shown the best performance compared to the two dominant feeding patterns in seawater desalination (FF and PF). With this background report, this study has focused on the further advancement of MED-MVC having a PCF configuration.…”