Development and Evaluation of an Alkaline Electrolyzer for Production of Hydrogen and Electrical Energy in a Fuel Cell

In this study, a single-cell, zero-gap, unipolar alkaline water electrolyzer which operates on a 30 wt.% KOH electrolyte solution was developed for production of hydrogen. Suitable material properties such as density, toughness, electrical conductivity, and corrosion resistivity were evaluated in Ansys Granta 2019 with the aid of material property charts; and thermal and stress simulations of the modelled components performed using Autodesk Inventor Nastran 2019. A DC power source supplied voltages below 3.0 V across the nickel electrodes, maintaining an operating temperature of 50 °C, and operating pressure at 0.1 MPa. The electrolytic process produced hydrogen and oxygen gases at the electrodes, and the membrane performed the gas separation. Polytetrafluoroethylene plastic was experimentally found to be a superior and more suitable material for the electrolyzer endplates and spacers to polypropylene plastic. Polypropylene nonwoven geotextile fabric was also found to be a low-cost and efficient membrane material, against Zirfon Perl UTP 500 membrane which is an efficient but expensive industrial membrane; polyester geotextile fabric got corroded after about 24 hours of good service. The optimal performance of the electrolyzer cell was obtained at a cell voltage of 2.2 V and a current of 1.30 A, while producing 14 ml of hydrogen gas per minute. This performance gave an electrolysis efficiency of 55.6%, an energy efficiency of 67.3%, and a hydrogen production efficiency of 75.4%. The produced hydrogen and oxygen gases generated electrical energy in a reversible PEM fuel cell device which powered a 0.2 W DC electric motor for a minute.