A unique study on the effect of dissolved gases and bubble temperatures on the ultrasonic hydrogen (sonohydrogen) production. (21st August 2020)

• Record Type: Journal Article
• Authors: Rashwan, Sherif S.; Dincer, Ibrahim; Mohany, Atef
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 41(2020)
• Page Start: 20808
• Page End: 20819
• Publication Date: 2020-08-21
• Subjects: CO2 -- Hydrogen -- Energy -- Efficiency -- Ultrasonic hydrogen production -- Sonohydrogen; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.05.022
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Producing hydrogen via sound waves offers a tremendous opportunity for generating an energy carrier in an environmentally-friendly manner. The open literature lacks research studies concerning the effect of the dissolved gases on the ultrasonic hydrogen production process (sonohydrogen) . Therefore, in this work, the effect of diluting different dissolved gases on the performance of the sonohydrogen process is studied. The present reaction kinetics mechanism consists of 19 reversible chemical reactions taking place inside the acoustic cavitation micro-bubble and is solved computationally. The results reveal that the dissolved gases have a significant effect on the chemical mechanism of the water vapor dissociation. The present study shows that using carbon dioxide as a dissolved gas within the sonohydrogen process enhances the hydrogen production rate. Two different bubble compositions are investigated; H2 O/O2 and H2 O/CO2 bubbles. In the case of the H2 O/O2 bubble, the energy efficiency is calculated, and its value ranges between 1.05 and 1.63 μmol/kWh, depending on the bubble's temperature. However, in the case of the H2 O/CO2 bubble, the hydrogen production shows a considerable improvement with energy efficiency in the range 22.26–34.98 μmol/kWh. This is due to the lower thermal conductivity, higher heat capacity, and lower thermal diffusivity of the composition of water vapor and carbon dioxide. Graphical abstract: Image 1 Highlights: Establishing a link between the acoustic bubble and chemical effects. Revealing a possible chemical reaction mechanism for Sonohydrogen process. Studying the effects of the dissolved gases on the hydrogen production rate. Proposing CO2 as a dissolved gas to enhance the hydrogen production rate.