Process Design and Techno-Economic-Environmental Assessment of the Solar High-Temperature Pyrolysis for Producing Ethylene Glycol from H₂O and CO₂

The supply contradiction of ethylene glycol (EG) in China is rising, and new technology should be explored to reduce CO2 emissions, energy consumption, and production costs in EG production to meet China’s carbon peak and carbon neutrality policy. This study proposes three solar high temperature pyrolysis of H2O/CO2 to EG technologies, including CO2 to EG technology (SCtEG), H2O to EG technology (SHtEG), and CO2–H2O to EG technology (SC–HtEG). Through industrial data and literature data and Aspen simulation, the validity of the technology model was established, the relevant parameters were studied and optimized, and their techno-economic-environmental performances were compared with those of coal to EG technology (CtEG). The process simulation results in Aspen software showed that the exergy efficiency of SCtEG and SC–HtEG increased from 30.68% to 47.21% and 40.43% and that of SHtEG was close to that of the CtEG process, at 25.68%. The new technologies can effectively reduce the total production cost by 34.07%, 29.47%, and 32.9%, respectively, and improve the internal rate of return by 10.09%, 1.42%, and 8.82%. The new technologies can achieve zero carbon emissions and use CO2 as crude material to produce EG, reducing the total greenhouse gas emissions to −6.01 t/t, −5.62 t/t and −6.02 t/t. This study may provide a theoretical basis and a feasible and sustainable pathway for the EG industry with high carbon emissions.