Techno-economic assessment of a novel integrated multigeneration system to synthesize e-methanol and green hydrogen in a carbon-neutral context

A novel and efficient multigeneration system aiming to achieve near-zero CO₂ emissions is proposed. The system employs a methanol production process utilizing captured CO₂ from the flue gas of a biomass-gasification plant. The proposed system successfully generates green H₂ through water electrolysis, supported by thermal power, with a portion of the hydrogen reacting with CO₂ to produce e-methanol. Additionally, the system produces other valuable products, including power, cooling, O₂, and CO₂, in a coherent manner, benefiting from a low-emission framework and exhibiting high thermodynamic performance. The proposed multigeneration system consists of a biomass-gasification-based power plant, a water electrolyzer, a methanol generation unit, a carbon capture unit, and a steam jet ejector-based refrigeration cycle. The integrated multigeneration system is analyzed from the energy, exergy, and economic aspects. The results demonstrate the system's ability to achieve production rates of 430.25 kg/h of e-methanol and 190 kg/h of green H₂. Furthermore, the energy and exergy efficiencies of the system are found to be 78.13% and 71.63%, respectively. The CO₂ emissions analysis reveals that the proposed system significantly reduced total CO₂ emission to 78.5% (0.61 kg_CO2/kg). The total cost of production is estimated to be 0.087 $/kg.