Transforming CO₂ Valorization: Tri-Reforming for Methanol Synthesis and Sustainable Emission Reduction in Power Plants Flue gas

The CO₂ consumption of flue gas for methanol production is investigated as an alternative for conventional, energy-intensive CO₂ capture methods in this study. Aspen HYSYS v12.1 was used to model the tri-reforming process, which aims to lower the carbon impact of traditional methods by converting CO₂ into methanol. With a stoichiometric number (Sn) of 2.216, the ideal H₂:CO ratio was determined to be 2.293. To obtain high CO₂ conversion rates at high temperatures, guarantee the required ratios, and reduce carbon formation on the catalyst, a nickel-based catalyst was employed in the tri-reforming process. With a methanol purity of 99.1%, methanol synthesis used a Cu/ZnO/Al₂O₃ commercial catalyst for CO hydrogenation, which significantly reduced carbon emissions to 0.032 kg CO₂ per kg of methanol.

This study discovered that Ni-based catalysts could accomplish 80–95% CH₄ conversion and good syngas selectivity at temperatures between 800 and 900°C and atmospheric conditions to moderate pressures while maintaining an ideal H₂/CO ratio of about 2.0–2.5. But because carbon deposition happened at rates of about 2–10 mgC/g-cat/h, more steam was needed for steam reforming in order to increase CO₂ conversion and decrease coke development. The highest H₂/CO ratio and the highest CH₄ and CO₂ conversion rates were obtained when operating at 850°C and 1 atm. Under conditions similar to those of natural gas-based power plants, simulation results demonstrated effective CO₂-to-methanol conversion with flue gas flow rates of 1000 kmol/h and 10 mol% CO₂. In order to optimize the reforming reactions and perhaps reduce reactor volume and mitigate high operating pressures, further reactor parameter optimization is advised, including introducing O₂ and H₂O. This study underlines the need for more research into process economics and scalability for large-scale implementation, while also highlighting the potential of tri-reforming for sustainable methanol synthesis from power plant emissions.