Thermodynamic analysis of ethanol synthesis by CO₂ hydrogenation using Aspen Plus: effects of tail gas recycling and CO co-feeding

Synthesis of ethanol by CO2 hydrogenation presents an efficient way to convert CO2 into value-added fuels and chemicals. For practical applications, recycling unreacted tail gas as well as CO co-feeding plays a key role to enhance CO2 conversion to ethanol. Thus, it is of great significance to study the effects of recycling unreacted tail gas and CO co-feeding on the chemical equilibrium. Herein, we perform a thermodynamic study to analyze the hydrogenation of CO2 to ethanol using Aspen Plus. The effects of recycling tail gas and CO co-feeding on CO2 conversion and ethanol selectivity at different temperatures and pressures are investigated. Both the optimal recycle ratio and CO/(CO + CO2) ratio in the feed are found to enhance ethanol synthesis from CO2 hydrogenation.