Productivity and Thermal Performance Enhancements of Hollow Fiber Water Gap Membrane Distillation Modules Using...

Area of Science:

• Membrane Science and Engineering
• Desalination Technologies
• Computational Fluid Dynamics (CFD)

Background:

• Hollow fiber water gap membrane distillation (HF-WGMD) offers advantages but needs improved distillate flux and productivity.
• Current HF-WGMD designs require optimization for enhanced desalination performance.

Purpose of the Study:

• To introduce and evaluate a novel HF-WGMD configuration incorporating helical turns within the water gap channel.
• To investigate the impact of helical membrane designs on mass transfer and energy conservation.

Main Methods:

• Development and validation of a fully coupled 3D Computational Fluid Dynamics (CFD) model.
• Simulation of transport phenomena, energy conservation, and diffusion mechanisms in helical HF-WGMD modules.
• Comparison of single and double helical designs against straight membrane modules under various operational conditions.

Main Results:

• A 11.4% enhancement in distillate flux was observed with 20 helical turns at 70 °C feed temperature.
• Specific productivity increased by a maximum of 46.2% using 50 helical turns.
• Energy savings of up to 35% in specific thermal energy consumption were achieved in a one-stage module.
• A 117.6% increase in gain output ratio was noted for a three-stage single helical module.

Conclusions:

• The proposed helical turn configuration significantly advances HF-WGMD module performance.
• This novel design offers substantial improvements in distillate flux, specific productivity, and energy efficiency.
• Helical HF-WGMD modules present a promising approach for more effective desalination.