A Study of the Optimized Conditions for a Closed-loop HHO Production System Using A/C Power Supply

Abstract

This study focused on finding appropriate conditions for HHO production by electrolysis using alkaline KOH electrolyte solution. The closed-loop HHO production unit designed consisted of a HHO generator, a liquid-gas separator and a cooling system. The experiments used electrolyte concentrations of 0.50, 0.75, 1.00, 1.25 and 1.50% w/w KOH (aq.), and 316L stainless steel 20x30 mm electrode plates. The gap between the plates was adjusted to 1, 3, 5, 7 and 9 mm, and experiments were conducted at the steady state temperatures 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 and 95°C for 10 minutes. It was found that as the electrolyte concentration increased from 0.50% to 1.50% w/w KOH, the HHO production rate increased by more than 50%, and also by more than 60% with increased operating temperature. Furthermore, at the high end of our operating temperatures, the small 1 and 3 mm cell gaps produced less HHO than the larger cell gaps. The optimized production conditions in this study had 7 mm cell gap and 1.50% w/w KOH at 90.0 + 1.0°C operating temperature. The appropriate operating pressure was also investigated for this closed-loop system to produce HHO by electrolysis of alkaline KOH electrolyte solution. The HHO production system still consisted of an HHO-generator, a liquid- gas separator and a cooling system. The operating pressure was set to 60.8, 70.9, 81.0, 91.2 or 101.3 kPa abs. The vacuum level was adjusted by varying the opening of the breathing valve at the suction line of the water-ring vacuum pump. It was found that the appropriate operating pressures matching an internal combustion engine (ICE) ranged from 81.0 to 91.2 kPa abs. The highest HHO production throughput occurred at 81.0 kPa abs, and was over twofold that at 101.3 kPa abs. However, at the lower pressures 70.9 and 60.8 kPa abs, the HHO throughput decreased by more than 50% and 80%, respectively. Furthermore, the 81.0 kPa abs operating pressure matches the intake manifold pressure of a running ICE, which generally ranges from 72.0 to 87.0 kPa abs.