Publication: Comparative study of hydrogen production from sonohydrogen and sono-electrolysis
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Date
2024-07-31
Authors
Liew, Sheng Yuh
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Abstract
Hydrogen (H2) is expected to be the new generation of fuel, surpassing conventional fossil fuels and coal in reducing carbon emissions. However, green H2 production constitutes only a minor part of the H2 production sector. Water electrolysis is a method for green H2 production but suffers from low Faraday efficiency. Ultrasound is seen as a method for green H2 production through either direct or auxiliary methods. Direct H2 production through ultrasound, known as sonohydrogen, uses the acoustic cavitation chemical effect, while auxiliary ultrasound to water electrolysis is called sono-electrolysis. This project aims to study the mechanism of the sonohydrogen process, evaluate different parameters affecting hydrogen production in electrolysis and sono-electrolysis, and calculate the energy efficiency and optimum conditions for both processes. Theoretical studies of sonohydrogen for acoustic bubble prediction, bubble dynamics, and bubble chemistry are evaluated to calculate H2 production. In the experiment involving electrolysis and sono-electrolysis, parameters such as temperature, solution concentration, voltage, and ultrasound power are varied. Results indicate that sonohydrogen produces H2 at 3.45x10-12 mol/s and 1.658x10-10 mol/s with energy efficiency 3.45x10-7 mol/kWh and 1.658x10-5 mol/kWh using dissolved gases O2 and CO2, respectively. The H2 production for electrolysis reaches an optimum condition at 129.5 cm3/h with an energy efficiency of 13.15%, while sono-electrolysis produces H2 at 265 cm3/h with an energy efficiency of 7.71% at the optimum condition. Ultrasound increases hydrogen production in electrolysis but reduces energy efficiency. A more detailed exploration of electrolysis and sono-electrolysis is still needed to achieve high H2 production with high energy efficiency.