Experimental Evaluation of Synthetic n-Propanol in a Dual-Fuel Engine and Modeling of Its Renewable Electrochemical Production from CO2

The use of synthetic fuels produced from CO2 requires efficient production technologies and evaluation of their application in energy systems. This study combines experimental tests of a dual-fuel engine powered by n-propanol and diesel fuel with modeling of electrochemical n-propanol synthesis from CO2. The aim was to determine the optimal n-propanol share and investigate the performance of a tandem electrochemical reactor. Increasing the energy share of n-propanol reduced CO and CO2 emissions. The highest engine efficiency of 33.94% was achieved at a 50% energy share of n-propanol, representing an increase of 1.5% compared with diesel-only operation. At this operating point, CO and CO2 emissions were reduced by 87.7% and 18.5%, respectively, compared with diesel-only operations. This point was selected for further analysis. A mathematical model of a tandem electrochemical reactor was developed. The system included CO2-to-CO conversion followed by n-propanol synthesis. The energy efficiencies of the CO generation and n-propanol synthesis reactors were 47.77% and 23.07%, respectively. Faradaic efficiency and cell voltage were the main factors affecting reactor performance. The overall tandem reactor efficiency ranged from 12% to 22%. The results confirm the potential of n-propanol as a dual-fuel engine fuel and identify key directions for improving electrochemical CO2 conversion.