Comparative energetic assessment of methanol production from CO2: Chemical versus electrochemical process.

Emerging emission-to-liquid (eTL) technologies that produce liquid fuels from CO 2 are a possible solution for both the global issues of greenhouse gas emissions and fossil fuel depletion. Among those technologies, CO 2 hydrogenation and high-temperature CO 2 electrolysis are two promising options suitable for large-scale applications. In this study, two CO 2 -to-methanol conversion processes, i.e., production of methanol by CO 2 hydrogenation and production of methanol based on high-temperature CO 2 electrolysis, are simulated using Aspen HYSYS. With Aspen Energy Analyzer, heat exchanger networks are optimized and minimal energy requirements are determined for the two different processes. The two processes are compared in terms of energy requirement and climate impact. It is found that the methanol production based on CO 2 electrolysis has an energy efficiency of 41%, almost double that of the CO 2 hydrogenation process provided that the required hydrogen is sourced from water electrolysis. The hydrogenation process produces more CO 2 when fossil fuel energy sources are used, but can result in more negative CO 2 emissions with renewable energies. The study reveals that both of the eTL processes can outperform the conventional fossil-fuel-based methanol production process in climate impacts as long as the renewable energy sources are implemented. [ABSTRACT FROM AUTHOR]