CO 2 Conversion Enhancement in a Periodically Operated Sabatier Reactor: Nonlinear Frequency Response Analysis and Simulation‐based Study

Conversion of CO 2 into synthetic CH 4 via thermocatalytic hydrogenation (the Sabatier reaction), has recently gained increasing interest as a possible route for CO 2 utilization and energy storage pathway. Herein, we analyze the possibility of increasing the CO 2 conversion through periodic operation of the reactor. The analysis is performed by using the Nonlinear Frequency Response (NFR) method, a recently developed analytical technique, suitable for fast evaluation of periodic reactor operations. The NFR analysis predicts a significant conversion gain (up to 50 %) for certain frequencies of the feed flow rate modulation. This prediction is validated by numerical simulations with a reaction rate expression obtained by CO 2 conversion experiments using a Ni/Al 2 O 3 catalysts. Both the NFR analysis and numerical simulations predict that it is possible to obtain 70 % CO 2 conversion at 500 K, 5 bar, and average space velocity of 7600 h −1 by a periodic modulation of the feed flow rate, as compared to the corresponding steady state CO 2 conversion of 43 %.