Energy Efficient Desalination Using Membrane Distillation
Membrane distillation (MD) is a low-cost thermal desalination process that uses the temperature difference across a hydrophobic membrane as the driving force. This temperature difference between the hot feed side (seawater) and cold permeate stream (pure water) creates a vapor pressure gradient which governs the pure water flux. Additionally, membrane hydrophobicity serves as a barrier for liquid entry, separating non-volatile impurtities and allowing only water vapor to pass through.
Our MD team in the Warsinger Water Lab at Purdue, researches on novel modifications to reduce the specific energy costs by improving the energy efficiency and permeate production of MD systems. Leading the computational efforts to model these enhancements, I am currently authoring (including both first author and co-author titles) a total of 7 journal publications.
Nanofluids in Membrane Distillation
- In this work, we suspend carbon nanotubes and copper oxide nanoparticles in the feed to modify the nanoscale thermal transport and achieve superior heat transfer enhancements. Few studies in the past have immobilized nanoparticles to absorb solar radiation as a thermal input for desalination but significant heat transfer enhancements can be obtained when they are suspended in the feed solutions as nanofluids.
- This work marks the first comprehensive study on nanofluids in membrane distillation (MD), modelling the micro-mixing, interactions of nanoparticles and characterizing their stable solutions and effects on membrane performance.
- For more details, please refer to the complete manuscript submitted to Nano Energy in January 2021.
Novel Condensation Regimes in Air Gap Membrane Distillation
- Gap based membrane distillation systems, enable internal heat recovery from vapor condensation and as a result effective regimes can significantly improve efficiency and pure water flux in MD. Our team investigates novel condensation regimes on nano-tailored surfaces and their effects on the performance of MD.
- We recently completed our studies on using slippery liquid infused porous condenser surfaces (SLIPS) and super-hydrophobic condensation surfaces for high efficiency air gap membrane distillation, capable of operating at a maximum first law efficiency of 95%.
- Currently, we are looking at porous copper condensors to mitigate flooding in membrane distillation with added performance benefits.
Rapid Vapor Flow in Vacuum Gap Membrane Distillation
- In this work, we are extensively modelling the mass transport in vacuum gap MD systems to develop a generic numerical algorithm capable of predicting the permeate flux at varying gap pressures.
- Utilizing this algorithm, we intend to comprehensively introduce an improved vacuum-air gap MD configuration capable of sustained performance with minimal added complexities.