Scale-up of membrane distillation systems using bench-scale data

• Published in: Desalination 2022-05, Vol.530, p.115654, Article 115654
• Main Authors: Hardikar, Mukta, Marquez, Itzel, Phakdon, Tenzin, Sáez, A. Eduardo, Achilli, Andrea
• Format: Article
• Language: English
• Subjects: Energy efficiency; High salinity; Membrane distillation coefficient; Membrane element design; Scale-up modeling
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2022.115654

A procedure to design full-scale air gap membrane distillation (AGMD) processes is presented. A mathematical model was then developed for both direct contact membrane distillation (DCMD) and AGMD. The model is centered on solving local mass and energy balances using a finite difference approach. The full-scale model was calibrated by utilizing the membrane distillation coefficient (MDC) determined by DCMD bench-scale experiments, as the sole adjustable parameter. The MDC was then used to model the water production and energy efficiency of a spiral-wound AGMD full-scale element. The model yields accurate representation of full-scale AGMD elements using polytetrafluoroethylene (PTFE) and polyethylene (PE) membranes. Full-scale experimental results obtained over a wide range of feed flow rates (2 to 4.5 L/min), temperatures (40 to 80 °C), and salinities (0 to 200 g/L NaCl) confirmed that the developed procedure can be applied to model and design large-scale AGMD elements. Furthermore, the model guides the selection of specific temperature and flow conditions at a given salinity and element geometry to maximize water production and energy efficiency. This methodology is suitable for rapid evaluation of novel MD membranes performance in field AGMD applications. [Display omitted] •Bench-scale direct contact membrane distillation data were used to scale-up air gap systems.•A model based on first principles was validated using two full-scale membrane elements.•The model forecasts production and efficiency for various feed salinities and element geometries.•This methodology is suitable for rapid evaluation of novel membranes in field application.•The model is suitable for determining operating conditions in field application.