Experimental study on water transport in membrane humidifiers for polymer electrolyte membrane fuel cells. (30th June 2022)

• Record Type: Journal Article
• Authors: Wolfenstetter, Florian; Kreitmeir, Michael; Schoenfeld, Ladislaus; Klein, Harald; Becker, Marc; Rehfeldt, Sebastian
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 55(2022)
• Page Start: 23381
• Page End: 23392
• Publication Date: 2022-06-30
• Subjects: PEM Fuel Cells -- Humidification -- Membranes -- Experimental -- Automotive Membrane Humidifier; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.05.114
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: This paper presents an experimental setup for the measurement of water transfer in membrane humidifiers for automotive polymer electrolyte membrane (PEM) fuel cells at different process conditions. This setup was used to determine steady-state water permeation through perfluorinated sulfonic acid (PFSA)-based polymer membranes. The process conditions were varied within a relative humidity in the feed stream of RH = 30–90 %, absolute pressures of p = 1.25–2.5 bar, and temperatures of T = 320–360 K. The examined membranes are Nafion® membranes of different thicknesses (Nafion® 211, 212 and 115) and an experimental composite membrane manufactured by W. L. Gore & Associates. It was found that the overall water permeance is affected by both the mass transfer resistance of the membrane and the resistances in the boundary layers of the adjacent gas streams. The overall permeance is a strong function of water activity, with high levels of relative humidity showing the highest overall permeance. The absolute pressure only affects the overall permeance by affecting the diffusion in the boundary layers. Lower pressures are preferable for high overall water permeances. Increasing temperatures favor diffusion in the membrane and the boundary layers but lead to lower sorption into the membrane. The thicker Nafion® membranes show lower overall permeance at higher temperatures, while the overall permeance of the composite membrane shows no dependency on the temperature. Investigation of membrane humidifiers in counter-, co-, and cross-flow shows that the flow configuration in our setup has very little impact on the water flux in the humidifier. Highlights: Improved experimental setup for measurement of water transport through membranes for membrane humidifiers in PEM fuel cells. Steady-state measurement data for Nafion® 211, 212, 115, and a composite membrane over a wide range of process conditions. Influence of membrane thickness and relative humidity, temperature, and pressure on the water transfer. Flow configuration of counter-, co-, and cross-flow have little effect on the water transfer in membrane humidifiers.