Application of microreactors and microprocess technology to power-to-X processes: Opportunities and challenges

Power-to-X (P-t-X) technologies enable the conversion of renewable electricity into storable fuels and chemicals, facilitating sector coupling. However, these technologies face limitations due to intermittency, scalability, and heat management. This study evaluates P-t-X routes for producing hydrogen, methanol, methane, Fischer-Tropsch fuels, and dimethyl ether at the microreactor scale and compares them with meso- and macroscales. A systematic evaluation of microreactor systems in P-t-X applications was conducted based on key performance indicators, including reaction conversion and selectivity, energy efficiency, scalability, modular integration, and operational flexibility. This study highlights the scale-dependent advantages and limitations of microreactor systems across different P-t-X pathways. A case study of CO 2 methanation with intermittent hydrogen production was conducted to evaluate the effects of reactor scale and modularity on annual methane production, hydrogen storage requirements, and operational flexibility under time-varying hydrogen supply conditions. The results show that all reactor scales achieve high annual methane production levels, close to the stoichiometric maximum of the Sabatier reaction. The required hydrogen storage varies substantially between configurations. The microreactor system achieves maximum methane production with an almost negligible hydrogen storage requirement, followed by the mesoscale configuration. The macroscale configurations, however, require a substantially larger storage capacity. These results demonstrate that increased reactor modularity significantly reduces storage dependence and enables a closer match between reactor throughput and hydrogen availability, thereby improving system operability without decreasing overall methane production potential.