Evaluation of an alternative process for the production of hydrocarbons from CO2: Techno-economic and environmental analysis

This study aims to evaluate and compare two integrated processes (Plant A and B) for hydrocarbon production from CO2. They involve proton exchange membrane water electrolysis for H2 production, reverse water-gas shift reaction for syngas production, pressure swing adsorption for syngas purification, Fischer-Tropsch synthesis for diesel-range hydrocarbons from CO2, and atmospheric distillation for product separation. Plant B additionally integrates a hydrocracking-based upgrading section. The simulations were performed using Aspen Plus (R) v10, Aspen Adsorption (R) v10, and Aspen Custom Modeler (R) v10. The evaluation covers technical, economic, environmental, and multi-criteria assessment (GREENSCOPE). The proposed processes demonstrate the potential to convert CO2 to hydrocarbons, with carbon conversion rates of 75% and 71% for Plants A and B, respectively. Process energy intensity is 155 and 170 MJ/kgLP for Plants A and B, respectively. Environmental assessment reveals CO2 reduction, resulting in negative global warming potentials of -2.20 and -0.84 kgCO2-eq/kgLP for Plants A and B, respectively. The sustainability degree indices for Plants A and B are 1.00 and 0.06, respectively, indicating Plant A as the more sustainable process alternative based on both quantitative and qualitative metrics. Economic analysis shows project unviability in the Brazilian context due to reliance on H2 production and prevailing pricing conditions. Economic viability requires a price increase of liquid products by 266% and 302% or CO2-eq abatement costs ranging from 2.05 to 3.43 US$/kgCO2-eq for Plants A and B, respectively. GREENSCOPE methodology indicates better performance for Plant A across all scores, highlighting a clear connection between the hydrocracking unit and performance indicators. The findings show that these processes align with sustainable development goals (SDGs) targets for climate action (SDG 13), clean energy (SDG 7), industry, innovation, and infrastructure (SDG 9), decent work and economic growth (SDG 8), and responsible consumption and production (SDG 12). Overall, the research moves forward SDGs by offering solutions to cut carbon emissions and promote sustainable industrial practices.