Techno-Economic Analysis Of CO2 To Methane Conversion

Human civilization has long depended on fossil fuels as the primary energy source, leading to significant carbon dioxide emissions. One method to reduce these emissions involves converting carbon dioxide into methane. This study developed a simulation model using ASPEN Plus™ software for a commercial-scale plant designed for this purpose, incorporating the Boudouard reaction, the Water-Gas Shift (WGS) reaction, and Fischer-Tropsch (FT) synthesis. A sodium-based catalyst in a fluidized bed reactor facilitated the Boudouard reaction at 900°C and 0.1 MPa, achieving 88% carbon conversion. The WGS reaction, conducted in a packed bed reactor at 400°C and 1.0 MPa with a copper-based catalyst, achieved 95% carbon monoxide conversion. The FT synthesis, also in a packed bed reactor at 240°C and 1.5 MPa with a cobalt-based catalyst, achieved 93% carbon monoxide conversion. The plant model produced 11.53 kg/h of methane from 100 kg/h of carbon dioxide and was validated against literature data. Feasibility studies, focusing on CAPEX, OPEX, ROI, and PBP, examined various carbon dioxide feed flow rates (100–500 kg/h) and feed compositions (0.2–1.0 mass fractions). While CAPEX, OPEX, and ROI values increased with both parameters, OPEX remained unaffected. The breakeven point for the model was determined to be at a carbon dioxide feed rate of 300 kg/h, highlighting the model’s potential scalability and economic viability for larger operations.