Sustainability Assessment of Thermocatalytic Conversion of CO2 to Transportation Fuels, Methanol, and 1-Propanol


Using captured CO2 as a chemical feedstock is widely considered toward establishing low carbon technologies to mitigate climate change. Process systems engineering analyses can help increase the chances of success by identifying attractive targets at early stages. Here, a comparative techno-economic and environmental analysis of three thermocatalytic CO2-based plants individually producing liquid hydrocarbon transportation fuels (LHTF), methanol, and 1-propanol is introduced. While the 1-propanol plant generates a remarkable profit, the LHTF and methanol plants are not economically viable, mainly due to the CO2 and H2 input cost. Sensitivity analysis shows that the feedstock prices need to drop by 80% for these two plants to break even. A tax structure is not a sensible option since it would be more than 4 times the highest carbon tax currently implemented in the country. In terms of the environmental performance, the CO2 utilization efficiencies are 45.5, 60.1, and −33.8% for LHTF, methanol, and 1-propanol syntheses, respectively. The negative utilization efficiency in the 1-propanol plant highlights the need of a greener production of its raw material ethylene. When the entire life cycles of the products are considered, these emerging plants emit 85.9, 77.4, and 35.9% less CO2 than their conventional counterparts for the same output. Our study provides the first evaluation of CO2-based 1-propanol synthesis, highlighting its potential, underscores gaps in the CO2-based LHTF, methanol, and 1-propanol by comparing them on a uniform common basis, and sets future research directions.
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