(390ah) Simulation and Techno-Economic Analysis of Direct Methanol Synthesis Via Chemical Looping

Methanol is a versatile chemical feedstock and promising alternative fuel that plays a critical role in sustainable chemical processes and renewable energy storage. Conventional industrial-scale methanol production primarily utilizes steam methane reforming (SMR), an energy-intensive process characterized by significant CO₂ emissions. Chemical Looping (CL) technology offers an innovative alternative capable of simultaneously generating high-purity CO₂ and a hydrogen-rich gas stream, addressing both environmental and efficiency concerns associated with conventional methanol synthesis methods. However, comprehensive techno-economic evaluations of integrated CL-based methanol production pathways remain insufficient, creating a critical knowledge gap regarding process feasibility and economic viability.

This study aims to: (1) develop a detailed Aspen Plus simulation model for an integrated chemical looping process designed specifically for simultaneous production of CO₂ and hydrogen-rich gas streams, followed by direct methanol synthesis; and (2) perform a techno-economic analysis to assess the competitiveness and scalability of the proposed process compared to traditional SMR methods. The chemical looping system consists of three interconnected reactors, Fuel Reactor (FR): Natural gas is introduced to react with oxidized CaFe₂O₄, producing primarily CO₂ and H₂O while reducing the oxygen carrier. This reactor operates at elevated temperatures, facilitating efficient methane conversion. Air Reactor (AR): Reduced CaFe₂O₄ from the FR is regenerated by reaction with air, replenishing the oxygen carrier and releasing heat utilized within the process. Steam Reactor (SR): The re-oxidized CaFe₂O₄ interacts with steam to yield a hydrogen-rich gas stream, primarily consisting of H₂ and residual H₂O. The resulting streams of hydrogen-rich gas and high-purity CO₂ are directly converted into methanol via catalytic synthesis under optimized industrial conditions, significantly simplifying traditional downstream processes. Subsequently, a distillation-based separation section ensures the methanol meets commercial purity standards (>99.5 wt%).

Simulation results indicate the CL-integrated methanol production system achieves an efficient conversion process, highlighting substantial environmental and process efficiency advantages over conventional SMR pathways. The techno-economic analysis, including capital expenditures (CAPEX), operating expenditures (OPEX), and the levelized cost of methanol (LCOM), demonstrates competitive economic performance for the proposed CL-based approach. Sensitivity analyses highlight the importance of operational parameters such as natural gas prices, electric price, and plant scale, identifying conditions under which the economic advantages of the CL-integrated methanol production process significantly improve. This work demonstrates the feasibility and promising economic potential of employing chemical looping as a sustainable and competitive alternative for direct methanol synthesis, aligning closely with global decarbonization and sustainability goals.