Experimental investigation of a novel sonic hydrogen generator

Abstract

This thesis presents an investigation of hydrogen generation using ultrasound technology. The experimental setup uses a newly developed integrated system employing ultrasound technology. The system operates at 40 kHz with a power output of 100 W. Various parameters such as temperature and isopropyl alcohol concentration are used to evaluate the hydrogen production process. Presented results indicate a variability in hydrogen production rates under different experimental conditions. For instance, distilled water at 25°C yields a hydrogen production rate of 0.059 μmol/min, which increases to 0.109 μmol/min at 70°C, demonstrating the positive impact of temperature on hydrogen yield. Other water resources such as tap water, lake water and wastewater also show improved hydrogen production rates at higher temperatures. The experimental datasets indicate that distilled water consistently produces the highest hydrogen yield compared to other water types. In terms of alcohol concentration, a 5% concentration produces the highest hydrogen production rate of 0.356 μmol/min. Additionally, CO₂ injection into the reactor enhances hydrogen production by up to 30%, whereas air injection leads to a hydrogen concentration of 83 ppm after 60 minutes. Compared to conventional electrolysis, ultrasound-assisted electrolysis increases hydrogen production from 0.0486 μmol/min to 0.092 μmol/min. The conceptual part of the research demonstrates the integration of this hydrogen production technique into renewable energy-based multigeneration systems, denoted as System 1,2 and 3. System 1 produces 12,839.5 kW of electrical power and 32.92 kg/h of hydrogen, with an energy efficiency increase from 37.68% to 55.32% by varying the solar tower's output temperature from 800 K to 1300 K. System 2 results show an energy efficiency of 83.28% and an exergy efficiency of 58.71%. Finally, system 3 demonstrates power generation using heliostats for solar concentration with energy and exergy efficiencies of 58.28% and 76.75%, respectively.