Scalable hydrogen production from a mono-circular filter press Divergent Electrode-Flow-Through alkaline electrolysis stack

Abstract

By incorporating all positive design criteria developed to date, to improve on performance and gas purities, a scalable and simplistic Mono-Circular Filter Press (MCFP) reactor has been developed and tested for the Divergent Electrode-Flow-Through (DEFT™) membraneless alkaline electrolysis technology. An improved gas/liquid separation methodology was utilised, which allows for hydrogen and oxygen gas purities of 99.81 and 99.50 vol% respectively, at the optimal flow velocity of 0.075 m s−1 and an electrode gap of 2.5 mm. Circular 30 mm mesh electrodes were utilised, with each electrode pair having its own independant pressurised chamber, with a unique indirect injection mechanism for the electrolyte. By incorporating a gas purge ensures that gas purity is maintained for long operational periods. By utilising a Ni/Ni catalyst combination, a current density of 1.14 A cm−2 at 2.5 VDC was obtained at a flow velocity of 0.075 m s−1, 60 °C, and an electrode gap of 2.5 mm. In utilising a double layer of mesh, with the same specification, and experimental conditions, a current density of 1.91 A cm−2 at 2.5 VDC was realised, providing evidence for the effectiveness of multi-layered porous electrodes for the DEFT™ principle. Future improvements will focus on reducing the footprint and electrolytic flow velocity for the technology