Experimental and analytical investigation of a new integrated reactor for hydrogen and methanol production with ocean carbon dioxide

This study introduces and evaluates a novel integrated three-compartment electrolytic cation exchange membrane (E-CEM) reactor designed for the simultaneous extraction of carbon dioxide (CO₂) from ocean water and the generation of hydrogen (H₂), with the goal of green methanol synthesis. The E-CEM reactor operates through electrochemical acidification and cation exchange processes to convert oceanic bicarbonates and carbonates into gaseous CO₂, while concurrently producing hydrogen via ocean water electrolysis. A maximum CO₂ extraction rate of 1514.60 mg/min is achieved under optimized conditions, 13–14.80 V, 1.80–2.0 M electrolyte concentration, and pH 2.2–3.0. Hydrogen generation increases to 2.07 mg/min at 12.80 V with 1.70 mol/L concentration. Further optimization of raising the concentration to 1.85 mol/L and reducing the pH to 2.0 increases H₂ production to 2.20 mg/min. In terms of sustainability, the E-CEM reactor demonstrates a 20% higher exergetic sustainability index compared to the peristaltic pump under ambient pressures ranging from 100 to 1000 kPa. In methane production tests using an H-cell setup, 1.5 M electrolyte yields the highest output, reaching 900 ppm during early stages. H-cell methanol synthesis, confirms via the acetylacetone spectrophotometric method, shows improved yields with increasing electrolyte concentration: 5.50 mg/L at 0.5 M, 7.20 mg/L at 1.5 M and 8.70 mg/L at 2.0 M. In the integrated H-cell and E-CEM configuration, methanol production reaches 4.20 mg/L at 7 V. Overall, the integrated E-CEM system demonstrates an energy efficiency of 7% and an exergy efficiency of 9%. While these values demonstrate promising performance, they also indicate room for further optimization. The E-CEM reactor is therefore placed as a promising and scalable green solution for sustainable CO₂ utilization and hydrogen-based energy systems.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Ontario Institute of Technology

Year dc:date.issued

2025

Author dc:creator

• Akci Turgut, Hilal Sayhan

Advisor dc:contributor.advisor

• Dincer, Ibrahim

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10155/2107

OAI identifier oai:identifier

oai:ontariotechu.scholaris.ca:10155/2107