Hydrogen production by alkaline water electrolysis and mathematical analysis

In this study, design, experimental studies and mathematical modeling of alkaline water electrolysis systems for hydrogen production were carried out. Parameters affecting voltage-current density performance were examined. Potassium hydroxide (KOH) as the electrolyte solution stainless steel as electrode material and Zirfon as membrane were used. For Electrolysis System-1 parametric studies were carried out by measuring current density and cell voltage according to applied voltage for the electrolyte concentration (0.30 M, 0.50 M and 0.75 M) and the distance between anode and cathode (18 mm, 22 mm). Cell performance boosted as the concentration was increased and distance was decreased. Experimental data was validated, and parameters were determined as a result of the modelling of Electrolysis System-1. For Electrolysis System 2 and 3 the effects of concentration (10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%), distance between electrodes (7 mm, 10 mm and 13 mm) and magnetic field (0 mT, 60 mT, 110 mT) on cell performance (V-i), hydrogen production rate and system efficiency were investigated. The highest value of cell performance was achieved under 30% concentration, 7 mm anode-cathode distance and 110 mT magnetic field operating conditions. Accordingly, system efficiency (HHV) was determined as 79% (30% KOH, 7 mm, 110 mT), 78% (30% KOH, 7 mm, 60 mT) ve 70% (30% KOH, 7 mm, 0 mT) in the range of 240-1100 A/m2 of current density. Modelling study for Electrolysis System-2 yielded validation in accordance with experimental data with the use of 20%-30% KOH and 7 mm anode-cathode distance.