Evaluating the environmental impacts of formic acid production from CO2: catalytic hydrogenation vs. electrocatalytic reduction†

Abstract

Carbon capture and utilization (CCU) technology provides a promising approach for minimizing greenhouse gas (GHG) emissions and fossil resource depletion. Formic acid (FA) is a valuable chemical that can be produced using various CCU technologies; so it is necessary to explore the environmental impacts of potential FA production technologies. This study quantified the two major environmental impacts (climate change and fossil depletion) for two CCU strategies (catalytic and electrocatalytic CO₂-based FA production) and compared them with the conventional strategy. Life cycle assessments were conducted for the integrated conversion and separation processes carried out in the Yeosu Industrial Complex in the Republic of Korea based on the literature data and simulation study. The results showed that the CCU strategies could reduce GHG emissions by 97%–132% (1.43–1.95 kg of CO₂ eq. per kg of pure FA) and save 69%–94% (0.56–0.78 kg oil eq. per kg of pure FA) of fossil resources compared with the conventional strategy. The major environmental drivers were identified for all strategies, and it was clear that the utility input was a major contributor to the environmental burden in all strategies. Scenarios in which the utility source and raw material supply were varied were analyzed to determine how to effectively reduce the environmental impact of CO₂-based FA production. Finally, several implications were proposed for the development of an environmentally feasible electrocatalytic CO₂-based FA production strategy: (1) improving the energy efficiency in reaction and separation and (2) introducing renewable electricity sources.