Thermo-economic and data-driven optimization of an integrated biomass gasification system for green hydrogen, ammonia, and methanol synthesis via dual hydrogen production routes

The global shift toward sustainable energy infrastructures has heightened interest in green material and fuel production pathways, particularly those that enable long-term energy storage. Biomass gasification coupled with downstream synthesis and chemical energy storage technologies has emerged as a promising approach for the co-generation of high-value chemicals and low-carbon fuels. This study presents a rigorous thermodynamic and techno-economic assessment of an integrated biomass-driven system configured for the simultaneous production and storage of energy in the form of methanol and ammonia. The proposed configuration incorporates a biomass gasifier supplying syngas to both synthesis loops, supported by heat-recovery strategies and organic Rankine cycles. A unique feature of this system is its dual hydrogen production strategy, utilizing both a Vanadium Chloride (VCl) thermochemical cycle and a Proton Exchange Membrane Electrolyzer (PEME). The integration of these dual hydrogen routes enhances the system’s operational flexibility and improves overall energy utilization and storage efficiency. A comprehensive parametric analysis was carried out by varying key operating variables, including water flow rate, air preheating temperature, and syngas combustion temperature, to examine their impacts on product formation rates, exergy efficiency, and total production cost of the stored chemical energy carriers. Additionally, system optimization was performed under two distinct operational scenarios aimed at minimizing production cost or maximizing thermodynamic performance. Under the cost-oriented scenario, the system produced 0.015 kg/s of methanol and 0.052 kg/s of ammonia at a total product cost of 40.34 $/GJ. In contrast, the efficiency-driven scenario yielded a higher methanol production rate of 0.016 kg/s and an exergy efficiency of 33.40%, accompanied by a modest cost increase to 42.49 $/GJ. Overall, the findings demonstrate the operational flexibility of the integrated system and underscore its potential to serve as a competitive, low-carbon energy storage and conversion route for producing green fuels and chemicals through targeted optimization.