Dynamic behavior and optimal regulation of seawater desalination by membrane distillation considering the membrane fouling

Abstract

Membrane distillation (MD) for seawater desalination is a promising technology to solve the shortage of freshwater because of its advantage of low energy consumption. However, membrane fouling is a common challenge that occurs during practical operation, resulting in decreased desalination performance. Since fouling phenomenon is a time-dependent process, a dynamic model of MD desalination considering membrane fouling is developed and experimentally validated in this study. The effects of key parameters on dynamic behavior considering the membrane fouling are investigated by this proposed model. The results indicate that membrane fouling has a significant effect on thin membranes as particles gradually accumulate on the membrane surface. Additionally, the rectangular shaped membrane exhibits better antifouling properties compared to the commonly used square shaped membrane. Inorganic pollution aggregation on the membrane surface is significantly enhanced by high temperature difference between the feed and permeate stream (ΔT), particularly in the initial stage. Increasing the feed stream rate (L) can alleviate organic pollutants and microbes. The model proposes hybrid optimal adjustment of ΔT and L to improve membrane antifouling properties. During the initial 30 h, the proposed approach leads to a 8.87% increase in permeation flux, but with the side effect of a 62.79% increase in energy consumption. The proposed dynamic model provides guidelines for optimizing MD desalination with better antifouling properties.