Experimental study on coalescer efficiency for liquid-liquid separation

The global community acknowledges water demand and accessibility as major challenges impacting human well-being. Forward Osmosis (FO) desalination coupled with concentrate solar power might represent a promising solution to combine water production with renewable sources. This work assesses the performance of a liquid-liquid separator (coalescer), an important component of the FO process, when using a polymeric thermo-responsive draw agent (PAGB2000). Experimental characterization of the coalescer is carried out for different regeneration temperatures (from 50 to 80 °C), residence time, draw concentration (from 0.30 to 0.60) and metal meshes. The separation efficiency of the coalescer can be as high as 95% for high residence time and regeneration temperatures (> 70 °C). Eventually, an analytical expression of the coalescer efficiency as function of the main operating parameters is proposed both to support desalination plant design and to enable understanding its applicability beyond its original context.