Integrating the Reverse Boudouard Reaction for a More Efficient Green Methanol Synthesis from CO$_2$ and Renewable Energy


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Date

2025-05-19

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Green methanol is an important renewable platform chemical that could be used to produce a wide range of sustainable products and fuels. However, it is currently economically unappealing. This high cost is mainly driven by the CO$_2$ hydrogenation process, which requires 50% more H$_2$ consumption than the classic fossil-based CO-rich syngas to methanol. To overcome this limitation, here we evaluate the economic and environmental implications of producing green methanol from electrolytic H$_2$ and captured CO$_2$ integrated with the reverse Boudouard (RB) reaction. We designed an integrated process based on a standard green methanol plant, adding an RB reactor to reduce CO$_2$ to CO using biochar prior to the methanol synthesis loop. Combining process simulation with life cycle assessment, we find that integrating both technologies leads to an economic and environmental win-win scenario compared with the base green methanol case. More specifically, production costs are decreased by 5% in an expanded system that assumes the simultaneous production of methanol, biogenic hydrogen, and industrial high-temperature heating under both scenarios. Furthermore, this alternative synthesis shows a reduced carbon footprint of 5% and a 4 to 10% improvement in human health, ecosystems quality, and resource scarcity, revealing no significant probability of associated burden shifting when expanding the system. Finally, when compared with fossil-based methanol, the RB integration makes green methanol competitive when H$_2$ is available at 3.5-2.0 dollar/kg, compared to the 2.3−1.3 dollar/kg required for the standard green methanol configuration. Our results highlight a potentially better alternative to direct CO$_2$ hydrogenation for green methanol synthesis and, in a broader context, demonstrate the benefits of integrating processes to exploit their synergies.

Publication status

published

Editor

Book title

Volume

13 (19)

Pages / Article No.

7088 - 7097

Publisher

American Chemical Society

Event

Edition / version

Methods

Software

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Date collected

Date created

Subject

CO$_2$ hydrogenation; reverse Boudouard reaction(RB); biochar; life cycle assessment (LCA); climate change; process simulation; win-win scenario; process integration

Organisational unit

09655 - Guillén Gosálbez, Gonzalo / Guillén Gosálbez, Gonzalo check_circle

Notes

Funding

180544 - NCCR Catalysis (phase I) (SNF)
225147 - NCCR Catalysis (51NF40_225147): Flexibility Grant (SNF)

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