The optimal carbon and hydrogen balance for methanol production from coke oven gas and Linz-Donawitz gas: Process development and techno-economic analysis

This study addresses the simulation and techno-economic analysis of novel methanol production processes by the combined feeding of hydrogen-rich coke oven gas (COG) and carbon-rich Linz-Donawitz gas (LDG). The optimal operating scheme and conditions to ensure the most favorable carbon and hydrogen balance of the proposed processes, maximized methanol production and polygeneration of methanol, power, and heat, were determined through a rigorous process simulation with a sequential quadratic programming optimization. A techno-economic analysis revealed that two combined-feeding processes show an improved technical and economic performance compared to the conventional methanol production process involving separated feeding of COG and LDG. The primary energy efficiency and minimum methanol selling price of the proposed processes were 51% and 60%, and 265 and 370 USD/ton, respectively, which were greatly improved compared to the base process. In addition, the CO₂ emissions of the two processes (0.41 and 1.03 kg of CO₂ per kW) imply that adjusting the optimal carbon and hydrogen balance is an important strategy to produce economically viable and environmentally clean methanol from residue gases of the steel industry.