Techno-Economic Analysis of Co-Producing Green Methanol and Green Formic Acid via Synergistic Integration of Biomass Gasification with CO2 Electro-Reduction

The transformation of the global energy landscape and the shortage of traditional fuels are driving the utilization of biomass. This study proposes a novel system for the co-production of green methanol and green formic acid by synergistically integrating biomass gasification with CO2 electro-reduction. The system model, developed using Aspen Plus with key units like the entrained-flow gasifier and a CO2 electro-reduction cell model, was evaluated from thermodynamic and economic perspectives. Results demonstrate that with 25% of the captured CO2 directed to electro-reduction, the system processing 14 150 t of biomass annually achieves remarkable energy and exergy efficiencies of 45.5% and 46.8%, respectively. It produces 6220 t of methanol and 1555 t of formic acid per year. The methanol production cost is 237.7 USD/t, with a payback period of 6.9 years. Equipment cost analysis shows the gasifier, air separation unit, and heat exchangers are the primary investments. Furthermore, a critical CO2 consumption ratio of 36.62% is identified, minimizing the payback period to 6.05 years, while energy efficiency monotonically decreases with a higher ratio due to increased purification duty. This work provides a valuable framework for efficient and flexible co-production of green fuels and chemicals, supporting the advancement of dual-carbon goals.