Techno-Economic Comparison of CO2 Valorization Through Chemical and Biotechnological Conversion

Carbon dioxide (CO₂) emissions have a significant impact on climate change and global warming, with concentrations exceeding the value established as a planetary limit (350 ppm CO₂). In Colombia, the manufacturing industries and the final consumption in households contribute to the highest emissions of CO₂ to the atmosphere. Sucre region, known for basing its economy on livestock and social services, is responsible for an annual emission of more than 3 Mton the CO₂ eq. Then, the state of novelty of this study is the applicability evaluation of methanol and ethanol production technologies based on CCU systems, in terms of techno-economic indicators, to be implemented in Sucre. Technical and economic assessment of the CO₂ valorization technologies towards methanol and ethanol production was carried out for a base case corresponding to a CO₂ inlet flow corresponding to 10% of the net CO₂ emissions in the region (i.e., 1750 kg_CO2/h). The results for methanol production through CO₂ hydrogenation presented a yield of 59.35% (kg_methanol/kg_CO2), a CO_2,out/CO_2,in ratio of 0.35, a profit margin of 51.07%, and a NPV of 33.42 M.USD. Moreover, the analysis of ethanol production by a biotechnological route to convert CO₂ using cyanobacteria (specifically S. elongatus sp. PCC 7942), presented a product yield of 17.61% (kg_ethanol/kg_CO2), a CO_2,out/CO_2,in ratio of 1.49 × 10^–4, a profit margin of 3.86%, and a NPV of − 71.28 M.USD. As conclusions, methanol production is the most viable option to be implemented in the Sucre region at all raw material scales considered. Furthermore, future studies should consider the impact of carbon credits within economic feasibility.

Graphical Abstract